Butadiene-isoprene diblock copolymers and process for the preparation thereof

Abstract

Butadiene-isoprene diblock copolymer formed by a block of crystalline polybutadiene (hard block) and by a block of amorphous polyisoprene (soft block). Said butadiene-isoprene diblock copolymer can be advantageously used both in the footwear industry (for example, in the production of shoe soles), and in the production of tires for motor vehicles and/or trucks.

Claims

1. Butadiene-isoprene diblock copolymer formed by a block of crystalline polybutadiene having a syndiotactic 1,2 unit content ≥60% and by a block of amorphous polyisoprene having a 3,4 atactic unit content ≥60%.

2. Butadiene-isoprene diblock copolymer according to claim 1, which is formed by: said block of crystalline polybutadiene having said syndiotactic 1,2 unit content ranging from 64% to 80%, and by said block of amorphous polyisoprene having said 3,4 atactic unit content ranging from 65% to 75%.

3. Butadiene-isoprene diblock copolymer according to claim 1, wherein in said butadiene-isoprene diblock copolymer: upon infra-red analysis referred to as FT-IR typical bands of cis-1,4 and 1,2 syndiotactic butadiene units centered at 737 cm.sup.−1 and 911 cm.sup.−1, respectively, and of isoprene cis-1,4 and 3,4 atactic units centered at 840 cm.sup.−1 and 890 cm.sup.−1, respectively.

4. Butadiene-isoprene diblock copolymer according to claim 1, wherein in said butadiene-isoprene diblock copolymer: said block of crystalline polybutadiene has a melting point referred to as T.sub.m that is greater than or equal to 65° C., and a crystallization temperature referred to as T.sub.c that is greater than or equal to 50° C.; said block of amorphous polyisoprene has a glass transition temperature referred to as T.sub.g that is lower than or equal to −35° C.

5. Butadiene-isoprene diblock copolymer formed by a block of crystalline polybutadiene and by a block of amorphous polyisoprene, wherein said butadiene-isoprene diblock copolymer has a polydispersion index, referred to as PDI, corresponding to the M.sub.w/M.sub.n ratio, in which M.sub.w=weight average molecular weight, M.sub.n=number average molecular weight, ranging from 2.0 to 2.6.

6. Butadiene-isoprene diblock copolymer according to claim 1, wherein said butadiene-isoprene diblock copolymer has a weight average molecular weight referred to as M.sub.w ranging from 600000 g/mol to 1300000 g/mol.

7. Process for the preparation of a butadiene-isoprene diblock copolymer according to claim 1 comprising the following steps: (i) subjecting 1,3-butadiene to living polymerization in the presence of a catalytic system comprising at least one iron complex having general formula (I) or (II): ##STR00006## wherein: R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7 and R.sub.8, identical or different, represent a hydrogen atom; or they are selected from a linear or branched, optionally halogenated, C.sub.1-C.sub.20 alkyl group, or an optionally substituted cycloalkyl group; or R.sub.4 and R.sub.5, may be optionally linked together to form, together with the other atoms to which they are linked, a saturated, unsaturated or aromatic cycle containing 4 to 6 carbon atoms, optionally substituted with a linear or branched, C.sub.1-C.sub.20 alkyl group; said cycle optionally containing a heteroatom; or R.sub.1 and R.sub.2 or R.sub.3 and R.sub.2, and/or R.sub.3 and R.sub.4, and/or R.sub.5 and R.sub.6, and/or R.sub.6 and R.sub.7 and/or R.sub.7 and R.sub.8, may be optionally linked together to form together with other atoms to which they are linked, a saturated, unsaturated or aromatic cycle containing 4 to 6 carbon atoms, optionally substituted with a linear or branched, C.sub.1-C.sub.20 alkyl group; said cycle optionally containing a heteroatom; X.sub.1 and X.sub.2, identical or different, represent a halogen atom; or are selected from a linear or branched C.sub.1-C.sub.20 alkyl group, an —OCOR.sub.9 group or an —OR.sub.9 group wherein R.sub.9 is selected from a linear or branched C.sub.1-C.sub.20 alkyl group; and continuing said living polymerization until substantially complete conversion of 1,3-butadiene; (ii) adding isoprene to the polymerization mixture obtained in step (i) and continuing said living polymerization until substantially complete isoprene conversion.

8. Process for the preparation of a butadiene-isoprene diblock copolymer according to claim 7, wherein in said iron complex having general formula (I) or (II): R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7 and R.sub.8, identical, represent a hydrogen atom; or R.sub.1, R.sub.2, R.sub.3, R.sub.6, R.sub.7 and R.sub.8, identical, represent a hydrogen atom and R.sub.4 and R.sub.5 are linked to form together with the other atoms to which they are linked a saturated, unsaturated, or aromatic cycle containing 4 to 6 carbon atoms; X.sub.1 and X.sub.2, identical or different, represent a halogen atom.

9. Process for the preparation of a butadiene-isoprene diblock copolymer according to claim 7, wherein said catalytic system comprises (b) at least one co-catalyst selected from: (b.sub.1) an aluminum alkyl having general formula (III):
Al(X′).sub.n(R.sub.10).sub.3-n  (III) wherein X′ represents a halogen atom; R.sub.10, identical or different, represents a hydrogen atom, or is selected from a linear or branched C.sub.1-C.sub.20 alkyl group, a cycloalkyl group, or an aryl group; said groups being optionally substituted with at least one silicon or germanium atom; and n is an integer ranging from 0 to 2; or (b.sub.2) an aluminoxane having general formula (IV):
(R.sub.11).sub.2—Al—O—[—Al(R.sub.12)—O-].sub.p-Al(R.sub.13).sub.2  (IV) wherein R.sub.11, R.sub.12 and R.sub.13, identical or different, represent a hydrogen atom, a halogen atom, or are selected from linear or branched C.sub.1-C.sub.20 alkyl groups, cycloalkyl groups, or aryl groups, said groups being optionally substituted with one or more silicon or germanium atoms; and p is an integer ranging from 0 to 1000.

10. Process for the preparation of a butadiene-isoprene diblock copolymer according to claim 7, wherein: said process is performed in the presence of an inert organic solvent comprising at least one solvent selected from: a saturated aliphatic hydrocarbon including at least one of butane, pentane, hexane, heptane, or mixtures thereof; a saturated cycloaliphatic hydrocarbon including at least one of cyclopentane, cyclohexane, or mixtures thereof; a mono-olefin including at least one of 1-butene, 2-butene, or mixtures thereof; an aromatic hydrocarbon including at least one of benzene, toluene, xylene, or mixtures thereof; or a halogenated hydrocarbon including at least one of methylene chloride, chloroform, carbon tetrachloride, trichlorethylene, perchlorethylene, 1,2-dichloroethane, chlorobenzene, bromobenzene, chlorotoluene, or mixtures thereof; and/or in step (i) of said process, the concentration of said 1,3-butadiene in said inert organic solvent ranges from 5% by weight to 50% by weight, relative to the total weight of said 1,3-butadiene and said inert organic solvent; and/or in step (ii) of said process, the isoprene concentration ranges from 5% by weight to 50% by weight, relative to the total weight of the polymerization mixture obtained in said step (i); and/or said process is performed at a temperature ranging from −70° C. to +100° C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS:

(1) FIG. 1 shows an example of the .sup.1H-NMR spectrum of a butadiene-isoprene diblock copolymer object of the present invention;

(2) FIG. 1A shows an example of the .sup.13C-NMR spectrum of a butadiene-isoprene diblock copolymer object of the present invention (specifically showing only the olefinic zone relative to the C4 carbon of a 1,2 structure butadiene unit).

(3) FIG. 2 shows the FT-IR spectrum of polybutadiene obtained in Example 5.

(4) FIG. 3 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of polybutadiene obtained in Example 5.

(5) FIG. 4 shows the FT-IR spectrum of polybutadiene obtained in Example 6.

(6) FIG. 5 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of polybutadiene obtained in Example 6.

(7) FIG. 6 shows the FT-IR spectrum of polybutadiene obtained in Example 7.

(8) FIG. 7 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of polybutadiene obtained in Example 7.

(9) FIG. 8 shows the FT-IR spectrum of polybutadiene obtained in Example 8.

(10) FIG. 9 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of polybutadiene obtained in Example 8.

(11) FIG. 10 shows the FT-IR spectrum of polyisoprene obtained in Example 9.

(12) FIG. 11 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of polyisoprene obtained in Example 9.

(13) FIG. 12 shows the FT-IR spectrum of butadiene-isoprene diblock copolymer obtained in Example 10.

(14) FIG. 13 shows the phase images obtained through AFM-Atomic Force Microscopy—of butadiene-isoprene diblock copolymer obtained in Example 10.

(15) FIG. 14 shows the FT-IR spectrum of butadiene-isoprene diblock copolymer obtained in Example 11.

(16) FIG. 15 shows the FT-IR spectrum of butadiene-isoprene diblock copolymer obtained in Example 12.

(17) FIG. 16 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of butadiene-isoprene diblock copolymer obtained in Example 12.

(18) FIG. 17 shows the FT-IR spectrum of butadiene-isoprene diblock copolymer obtained in Example 13.

(19) FIG. 18 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of butadiene-isoprene diblock copolymer obtained in Example 13.

(20) FIG. 19 shows the FT-IR spectrum of butadiene-isoprene diblock copolymer obtained in Example 14.

(21) FIG. 20 shows the FT-IR spectrum of butadiene-isoprene diblock copolymer obtained in Example 15.

(22) FIG. 21 shows the FT-IR spectrum of butadiene-isoprene diblock copolymer obtained in Example 16.

(23) FIG. 22 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of butadiene-isoprene diblock copolymer obtained in Example 16.

(24) FIG. 23 shows phase images obtained through AFM-Atomic Force Microscopy—of butadiene-isoprene diblock copolymer obtained in Example 16.

(25) FIG. 24 shows the FT-IR spectrum of butadiene-isoprene diblock copolymer obtained in Example 17.

(26) FIG. 25 shows the FT-IR spectrum of butadiene-isoprene diblock copolymer obtained in Example 18.

(27) FIG. 26 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of butadiene-isoprene diblock copolymer obtained in Example 18.

(28) FIG. 27 shows phase images obtained through AFM-Atomic Force —of a mechanical mixture of crystalline 1,2 syndiotactic polybutadiene and amorphous 3,4 atactic polyisoprene obtained in Example 19.

(29) For the purpose of understanding the present invention better and to put it into practice, below are some illustrative and non-limiting examples thereof.

EXAMPLES

(30) Reagents and Materials

(31) The list below reports the reagents and materials used in the following examples of the invention, any pre-treatments thereof and their manufacturer: anhydrous iron(II) chloride (FeCl.sub.2) (Aldrich): purity 97%, used as such; iron(II) chloride tetrahydrate (FeCl.sub.2.4H.sub.2O) (Aldrich): purity 99.99%, used as such; 2,2′-bipyridine (Aldrich): purity a ≥98%, used as such; 1,10-phenanthroline (Aldrich): purity ≥99%, used as such; phosphoric anhydride (P.sub.2O.sub.5) (Aldrich): purity ≥99%, used as such; methylaluminoxane (MAO) (toluene solution 10% in weight) (Aldrich): used as such; tri-iso-butyl-aluminum (TIBA) (Aldrich): purity ≥99%, used as such; pentane (Fluke): purity 99%, refluxed over a sodium/potassium (Na/K) alloy in a nitrogen atmosphere for about 8 hours and subsequently distilled and maintained in said atmosphere, at 4° C., on molecular sieves; heptane (Fluka): purity 99%, refluxed over a sodium/potassium (Na/K) alloy in a nitrogen atmosphere for about 8 hours and subsequently distilled and maintained in said atmosphere, at 4° C., on molecular sieves; toluene (Fluke); purity ≥99.5%, refluxed over sodium (Na) in a nitrogen atmosphere for about 8 hours and subsequently distilled and maintained in said atmosphere, at 4° C., on molecular sieves; diethylether (Aldrich): purity ≥99.8%, refluxed over a sodium/potassium (Na/K) alloy in a nitrogen atmosphere for about 8 hours and subsequently distilled and maintained in said atmosphere, at 4° C., on molecular sieves; 1,2-dichlorobenzene (Aldrich): purity ≥99%, refluxed over calcium hydride (CaH.sub.2) in a nitrogen atmosphere for about 8 hours and subsequently distilled and maintained in said atmosphere, at 4° C., on molecular sieves; 1,3-butadiene (Air Liquide): purity ≥99.5%, evaporated from the container before each production, dried by passing it through a molecular sieve packed column and condensed inside the reactor that was pre-cooled to −20° C.; isoprene (Aldrich): purity ≥99%, refluxed over calcium hydride (CaH.sub.2) for 2 hours, then distilled “trap-to-trap” and stored in a nitrogen atmosphere at 4° C.; ethanol (Carlo Erba, RPE): anhydrified through distillation on magnesium (Mg) and subsequently degassed; methanol (Carlo Erba, RPE): used as such; hydrochloric acid in 37% aqueous solution (Aldrich): used as such; dichloromethane (CH.sub.2Cl.sub.2) (Acros): pure, ≥99.9%, used as such; hydrofluoric acid (HF) (40% aqueous solution) (Aldrich): used as such; sulfuric acid (H.sub.2SO.sub.4) (96% aqueous solution) (Aldrich): used as such; nitric acid (HNO.sub.3) (70% aqueous solution) (Aldrich): used as such; sodium carbonate (Na.sub.2CO.sub.3) (Aldrich): used as such; silver nitrate (AgNO.sub.3) (Aldrich): used as such; deuterated tetrachloroethylene (C.sub.2D.sub.2Cl.sub.4) (Acros): used as such; hexamethyldisilazane (HMDS) (Acros): used as such; deuterated chloroform (CDCl.sub.3) (Aldrich): used as such; tetramethylsilane (TMS) (Acros): used as such; chloroform (CH.sub.2Cl.sub.3) (Aldrich): used as such.

(32) Analysis and Characterization Methods

(33) The analysis and characterization methods reported below were used.

(34) Elementary Analysis

(35) a) Determination of Fe

(36) For the determination of the quantity by weight of iron (Fe) in the iron complexes used in the present invention, an exactly weighed aliquot, operating in dry-box under nitrogen flow, of about 30 mg-50 mg of sample, was placed in a 30 ml platinum crucible, together with a 1 ml mixture of 40% hydrofluoric acid (HF), 0.25 ml of 96% sulfuric acid (H.sub.2SO.sub.4) and 1 ml of 70% nitric acid (HNO.sub.3). The crucible was then heated on a hot plate increasing the temperature until white sulfur fumes appeared (about 200° C.). The mixture thus obtained was cooled to ambient temperature and 1 ml of 70% nitric acid (HNO.sub.3) was added, then it was left again until fumes appeared. After repeating the sequence another two times, a clear, almost colorless, solution was obtained. 1 ml of nitric acid (HNO.sub.3) and about 15 ml of water were then added cold, then heated to 80° C. for about 30 minutes. The sample thus prepared was diluted with MilliQ pure water until it weighed about 50 g, precisely weighed, to obtain a solution on which the instrumental analytical determination was performed using a Thermo Optek IRIS Advantage Duo ICP-OES (plasma optical emission) spectrometer, for comparison with solutions of known concentration. For this purpose, for every analyte, a calibration curve was prepared in the range 0 ppm-10 ppm, measuring calibration solutions by dilution by weight of certified solutions.

(37) The solution of sample prepared as above was then diluted again by weight in order to obtain concentrations close to the reference ones, before performing spectrophotometric measurement. All the samples were prepared in double quantities. The results were considered acceptable if the individual repeated test data did not have a relative deviation of more than 2% relative to their mean value.

(38) b) Determination of Chlorine

(39) For said purpose, samples of the iron complexes used in the present invention, about 30 mg-50 mg, were precisely weighed in 100 ml glass beakers in dry-box under nitrogen flow. 2 g of sodium carbonate (Na.sub.2CO.sub.3) were added and, outside the dry-box, 50 ml of MilliQ water. It was brought to the boil on the hot plate, under magnetic stirring, for about 30 minutes. It was left to cool, then 1/5 diluted sulfuric acid (H.sub.2SO.sub.4) was added, until acid reaction and was then titrated with 0.1 N silver nitrate (AgNO.sub.3) with a potentiometric titrator.

(40) c) Determination of Carbon, Hydrogen and Nitrogen

(41) The determination of carbon, hydrogen and nitrogen, in the iron complexes used in the present invention, as well as in the ligands used for the purpose of the present invention, was performed through a Carlo Erba automatic analyzer Mod. 1106.

(42) .sup.13C-NMR and .sup.1H-NMR Spectra

(43) The .sup.13C-NMR and .sup.1H-NMR spectra were recorded using a nuclear magnetic resonance spectrometer mod. Bruker Avance 400, using deuterated tetrachloroethylene (C.sub.2D.sub.2Cl.sub.4) at 103° C., and hexamethyldisilazane (HDMS) as internal standard, or using deuterated chloroform (CDCl.sub.3), at 25° C., and tetramethylsilane (TMS) as internal standard. For this purpose, copolymeric solutions were used with concentrations equal to 10% by weight relative to the total weight of the copolymeric solution.

(44) The microstructure of the butadiene-isoprene diblock copolymers according to the present invention [i.e. cis-1,4(%) and 1,2 syndiotactic (%) unit content for polybutadiene and cis-1,4(%), 3,4 atactic (%) unit content for polyisoprene] was determined through the analysis of the aforementioned spectra based on the contents reported in literature by Mochel, V. D., in “Journal of Polymer Science Part A-1: Polymer Chemistry” (1972), Vol. 10, Issue 4, pg. 1009-1018 for polybutadiene, and by Sato H. et al. in “Journal of Polymer Science: Polymer Chemistry Edition” (1979), Vol. 17, Issue 11, pg. 3551-3558, for polyisoprene. For that purpose:

(45) FIG. 1 shows, by way of example, the .sup.1H-NMR spectrum of a butadiene-isoprene diblock copolymer object of the present invention from which, as reported below, it is possible to determine the composition and the microstructure of said copolymer; FIG. 1/A, shows, by way of example, the .sup.13C-NMR spectrum of a butadiene-isoprene diblock copolymer object of the present invention (specifically showing only the olefinic zone relative to the C4 carbon of a 1,2 structure butadiene unit) from which, as reported below, it is possible to determine the percentage of syndiotactic triad [(rr) %] in the block of polybutadiene having a 1,2 structure of said copolymer.

(46) In particular, in FIG. 1: A=area of the peaks ranging from 5.15 ppm to 5.65 ppm, corresponding to the two olefinic protons of a butadiene unit having a cis-1,4 structure and to one of the three olefinic protons of a butadiene unit having a 1,2 structure; B=area of the peak ranging from 5.0 ppm to 5.15 ppm, relative to the olefinic proton of a cis-1,4 isoprene unit; C=area of the peaks ranging from 4.75 ppm to 5.0 ppm, corresponding to two of the three olefinic protons of a butadiene unit having a 1,2 structure; D=area of the peaks ranging from 4.45 ppm to 4.75 ppm, corresponding to two of the three olefinic protons of a butadiene unit having a 3,4 structure.

(47) The composition and the microstructure of the butadiene-isoprene dibiock copolymers object of the present invention is therefore obtained from the following equations:
total % content of isoprene units (cis-1,4+3,4): {(D+2B)/[(D+2B]+(A+C/2)]}×100;
total % content of butadiene units (cis-1,4+1,2): {(A+C/2)/[(D+2B]+(A+C/2)}×100;
percentage of 1,2 units in the butadiene block: [C/(A+C/2)]×100;
percentage of 3,4 units in the isoprene block: [D/(D+2B)]×100.

(48) In particular, in FIG. 1/A, the .sup.13C-NMR spectrum shown therein (as specified above, only the olefinic zone relative to the C4 carbon of a 1,2 structure butadiene unit is shown), the percentage of syndiotactic triads [(rr) %] in the block of polybutadiene having 1,2 structure has been obtained from the areas of the peaks related to the C4 olefinic carbon of a 1,2 unit, through the following equations:
content of syndiotactic triads [(rr) %]: [(rr)%]={[rr]/[rr+mr+mm]}×100

(49) wherein:

(50) [rr]: area of the peaks related to the syndiotactic triad;

(51) [mr]: area of the peaks related to the atactic triad;

(52) [mm]: area of the peaks related to the isotactic triad.

(53) I.R. Spectra

(54) The I.R. spectra (FT-IR) were recorded through Thermo Nicolet Nexus 670 and Bruker IFS 48 spectrophotometers.

(55) The I.R. spectra (FT-IR) of the of the butadiene-isoprene diblock copolymers object of the present invention, were obtained from polymeric films on potassium bromide (KBr) tablets, said films being obtained through the deposition of a solution in hot 1,2-dichlorobenzene of the butadiene-isoprene diblock copolymer to be analyzed. The concentration of the copolymeric solutions analyzed was equal to 10% by weight relative to the total weight of the copolymeric solution.

(56) Thermal Analysis (DSC)

(57) The DSC—Differential Scanning calorimetry—thermal analysis, for the purpose of determining the melting point (T.sub.m) and the crystallization temperature (T.sub.c) of the butadiene-isoprene diblock copolymers object of the present invention, was performed using a Perkin Elmer Pyris differential scanning calorimeter. For this purpose, 5 mg of the butadiene-isoprene diblock copolymer obtained were analyzed, with a scanning speed ranging from 1° C./min to 20° C./min, in an inert nitrogen atmosphere.

(58) The DSC—Differential Scanning calorimetry—thermal analysis, for the purpose of determining the glass transition temperature (T.sub.g) of the butadiene-isoprene diblock copolymers obtained, was performed by means of the aforementioned calorimeter, using the following thermal program: isotherm for 3 min at +70° C.; cooling from +70° C. to −90° C. at a speed of 10° C./min; isotherm for 3 min at −90° C.; heating from −90° C. to +70° C. at a speed of 10° C./min.

(59) Determination of the Molecular Weight

(60) The determination of the molecular weight (MW) of the butadiene-isoprene diblock copolymers object of the present invention was performed through GPC (Gel Permeation Chromatography), using the Waters® Alliance® GPCN 2000 System by Waters Corporation which uses two detection lines: “Refractive Index”—RI and “Viscometer” operating under the following conditions: two PLgel Mixed-B columns; solvent/eluent: 1,2-dichlorobenzene (Aldrich); flow rate: 0.8 ml/min; temperature: 145° C.; molecular mass calculation: Universal Calibration method.

(61) The weight-average molecular weight (M.sub.w) and the polydispersion index (PDI) are reported, corresponding to the ratio M.sub.w/M.sub.n (M.sub.n=number average molecular weight).

(62) AFM—Atomic Force Microscopy

(63) For the purpose, a thin film of the butadiene-isoprene diblock copolymer object of the present invention to be analyzed was prepared, by depositing a solution in chloroform or in toluene, of said copolymer, through spin-coating on a silicon substrate.

(64) The analysis was performed in the absence of dynamic contact (not contact mode or tapping mode), using an NTEGRA Spectra Atomic Force Microscope made by N-MDT. During the scanning of the surface of said thin film, the amplitude variations of the oscillations of the tip provide topographic information related to the surface thereof (HEIGHT image). Furthermore, the phase variations of the oscillations of the tip may be used to discriminate between different types of materials present on the surface of said film (different material phases). By way of example, FIGS. 13 and 23 below show the images obtained from the analysis performed on the butadiene-isoprene diblock copolymers formed by the crystalline polybutadiene (hard block)-amorphous polyisoprene (soft block) of Example 10 and Example 16, respectively, which can be compared with the images of FIG. 27 obtained from the analysis performed on the mechanical mixture of two homopolymers (Example 19).

Example 1

Synthesis of Fe(bipy)Cl.SUB.2

(65) ##STR00002##

(66) 0.585 g (4.61 mmoles) of anhydrous iron dichloride (FeCl.sub.2) and 60 ml of ethanol (anhydrous and degassed) were loaded into a 250 ml flask, in an inert atmosphere: the whole was left, under stirring, at 60° C., until the dissolution of the anhydrous iron dichloride (FeCl.sub.2). Subsequently, 0.504 g (3.23 mmoles) of 2,2′-bipyridine (bipy) dissolved in 30 ml of ethanol (anhydrous and degassed) were added slowly: the whole was left under stirring, in an inert atmosphere, at 60° C., for 5 minutes. The suspension obtained was cooled to room temperature, and the solid obtained was recovered by filtration, washed with ethanol (anhydrous and degassed) (2×5 ml) and vacuum dried, at room temperature, obtaining 0.730 g of a solid product corresponding to the complex Fe(bipy)Cl.sub.2, equal to an 80% conversion relative to the 2,2′-bipyridine (bipy) loaded.

(67) Molecular weight (MW): 282.93.

(68) Elementary analysis [found (calculated for C.sub.10H.sub.8Cl.sub.2FeN.sub.2)]: C: 42.55% (42.45%), H: 2.96% (2.85%), N: 9.80% (9.90%), Cl: 25.30% (25.06%), Fe: 19.82% (19.74%).

Example 2

Synthesis of Fe(phen)Cl.SUB.2

(69) ##STR00003##

(70) 0/24 g (5.71 mmoles) of anhydrous iron dichloride (FeCl.sub.2) and 65 ml of ethanol (anhydrous and degassed) were loaded into a 250 ml flask, in an inert atmosphere: the whole was left, under stirring, in an inert atmosphere, at 60° C., until the dissolution of the anhydrous iron dichloride (FeCl.sub.2). Subsequently, 0.721 g (4 mmoles) of 1,10-phenanthroline (phen) dissolved in 40 ml of ethanol (anhydrous and degassed) were added slowly: the whole was left under stirring, in an inert atmosphere, at 60° C., for 5 minutes. The solution obtained was cooled to room temperature, and the precipitate obtained was recovered by filtration, washed with ethanol (anhydrous and degassed) (2×5 ml) and vacuum dried, at room temperature, obtaining 0.983 g of a solid product corresponding to the complex Fe(phen)Cl.sub.2, equal to an 80% conversion relative to the 1,10-phenanthroline (phen) loaded.

(71) Molecular weight (MW): 306.96.

(72) Elementary analysis [found (calculated for C.sub.12H.sub.8Cl.sub.2FeN.sub.2)]: C: 46.87% (46.95%), H: 2.66% (2.63%), N: 9.20% (9.13%), Cl: 23.35% (23.10%), Fe: 18.22% (18.19%).

Example 3

Synthesis of Fe(bipy).SUB.2.Cl.SUB.2

(73) ##STR00004##

(74) 1.29 g (6.5 mmoles) of iron dichloride tetrahydrate (FeCl.sub.2.4H.sub.2O), 30 ml of water and 3.05 g (19.5 mmoles) of 2,2′-bipyridine (bipy) were loaded, in an inert atmosphere, into a 100 ml flask: the whole was left, under stirring, at room temperature, for 1 hour. The reaction mixture obtained was vacuum dried, at 50° C., obtaining a solid that was vacuum heated at 100° C., for 12 hours, in the presence of phosphoric anhydride (P.sub.2O.sub.5) obtaining 2.4 g of a solid product corresponding to the complex Fe(bipy).sub.2Cl.sub.2, equal to an 85% conversion relative to the iron dichloride tetrahydrate (FeCl.sub.2′4H.sub.2O) loaded.

(75) Molecular weight (MW): 439.12.

(76) Elementary analysis [found (calculated for C.sub.20H.sub.16Cl.sub.2FeN.sub.4)]: C: 54.75% (54.70%), H: 3.82% (3.67%), N: 12.67% (12.76%), Cl: 15.97% (16.15%), Fe: 12.60% (12.72%).

Example 4

Synthesis of Fe(phen).SUB.2.Cl.SUB.2

(77) ##STR00005##

(78) 1.29 g (6.5 mmoles) of iron dichloride tetrahydrate (FeCl.sub.2.4H.sub.2O), 30 ml of water and 3.62 g (19.5 mmoles) of 1,10-phenanthroline (phen) were loaded, in an inert atmosphere, into a 100 ml flask: the whole was left, under stirring, at room temperature, for 1 hour. The reaction mixture obtained was vacuum dried, at 50° C., obtaining a solid that was vacuum heated at 160° C., for 12 hours, in the presence of phosphoric anhydride (P.sub.2O.sub.5) obtaining 2.7 g of a solid product corresponding to the complex Fe(phen).sub.2Cl.sub.2, equal to an 85% conversion relative to the iron dichloride tetrahydrate (FeCl.sub.2.4H.sub.2O) loaded.

(79) Molecular weight (MW): 487.16.

(80) Elementary analysis [found (calculated for C.sub.24H.sub.16Cl.sub.2FeN.sub.4)]: C: 59.23% (59.17%), H: 3.56% (3.31%), N: 11.58% (11.50%), Cl: 14.62% (14.55%), Fe: 11.66% (11.46%).

Example 5

Synthesis of Crystalline Polybutadiene Having a 64.6% Content of 1,2 Syndiotactic Units (Reference Homopolymer)

(81) 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.), in a 25 ml test tube. Subsequently, 14.59 ml of toluene were added and the temperature of the solution thus obtained was brought to +40° C. Then, methylaluminoxane (MAO) in toluene solution (0.315 ml; 5×10.sup.−4 moles, equal to about 0.029 g) was added, and, subsequently, the Fe(bipy).sub.2Cl.sub.2 (1.1 ml of toluene solution at a concentration of 2 mg/ml; 5×10.sup.−6 moles, equal to about 2.2 mg) obtained as described in Example 3. The whole was kept, under magnetic stirring, at +40° C., for 5 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 1,4 g of polybutadiene having a 1,2-cis syndiotactic unit content of 64.6%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

(82) FIG. 2 shows the FT-IR spectrum of the polybutadiene obtained.

(83) FIG. 3 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of the polybutadiene obtained.

Example 6

Synthesis of Crystalline Polybutadiene 68.3% Content of 1,2 Syndiotactic Units (Reference Homopolymer)

(84) 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.), in a 25 ml test tube. Subsequently, 14.59 ml of toluene were added and the temperature of the solution thus obtained was brought to +22° C. Then, methylaluminoxane (MAO) in toluene solution (0,315 ml; 5×10.sup.−4 moles, equal to about 0.029 g) was added, and, subsequently, the Fe(bipy).sub.2Cl.sub.2 (1.1 ml of toluene solution at a concentration of 2 mg/ml; 5×10.sup.−6 moles, equal to about 2.2 mg) obtained as described in Example 3. The whole was kept, under magnetic stirring, at +22° C., for 5 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 1.4 g of polybutadiene having a 1,2-cis syndiotactic unit content of 68.3%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

(85) FIG. 4 shows the FT-IR spectrum of the polybutadiene obtained.

(86) FIG. 5 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of the polybutadiene obtained.

Example 7

Synthesis of Crystalline Polybutadiene Having a 77.4% Content of 1,2 Syndiotactic Units (Reference Homopolymer)

(87) 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.), in a 25 ml test tube. Subsequently, 14.59 ml of toluene were added and the temperature of the solution thus obtained was brought to 0° C. Then, methylaluminoxane (MAO) in toluene solution (0.315 ml; 5×10.sup.−4 moles, equal to about 0.029 g) was added, and, subsequently, the Fe(bipy).sub.2Cl.sub.2 (1.1 ml of toluene solution at a concentration of 2 mg/ml; 5×10.sup.−6 moles, equal to about 2.2 mg) obtained as described in Example 3. The whole was kept, under magnetic stirring, at 0° C., for 15 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 1.4 g of polybutadiene having a 1,2-cis syndiotactic unit content of 77.4%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

(88) FIG. 6 shows the FT-IR spectrum of the polybutadiene obtained.

(89) FIG. 7 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of the polybutadiene obtained.

Example 8

Synthesis of Crystalline Polybutadiene Having a 83.2% Content of 1,2 Syndiotactic Units (Reference Homopolymer)

(90) 2 ml of 1,3-butadiene equal to about 1.4 g were condensed, cold (−20° C.), in a 25 ml test tube. Subsequently, 14.59 ml of toluene were added and the temperature of the solution thus obtained was brought to −20° C. Then, methylaluminoxane (MAO) in toluene solution (0.315 ml; 5×10.sup.−4 moles, equal to about 0.029 g) was added, and, subsequently, the Fe(bipy).sub.2Cl.sub.2 (1.1 ml of toluene solution at a concentration of 2 mg/ml; 5×10.sup.−6 moles, equal to about 2.2 mg) obtained as described in Example 3. The whole was kept, under magnetic stirring, at −20° C., for 30 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 1.4 g of polybutadiene having a 1,2-cis syndiotactic unit content of 83.2%: further characteristics of the procedure and of the polybutadiene obtained are reported in Table 1.

(91) FIG. 8 shows the FT-IR spectrum of the polybutadiene obtained.

(92) FIG. 9 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of the polybutadiene obtained.

Example 9

Synthesis of Amorphous Polyisoprene Having a 67.0% Content of 3,4 Atactic Units (Reference Homopolymer)

(93) 2 ml of isoprene equal to about 1.36 g were loaded into a 25 ml test tube. Subsequently, 14.59 ml of toluene were added and the temperature of the solution thus obtained was brought to +20° C. Then, methylaluminoxane (MAO) in toluene solution (0.315 ml; 5×10.sup.−4 moles, equal to about 0.029 g) was added, and, subsequently, the Fe(bipy).sub.2Cl.sub.2 (1.1 ml of toluene solution at a concentration of 2 mg/ml; 5×10.sup.−6 moles, equal to about 2.2 mg) obtained as described in Example 3. The whole was kept, under magnetic stirring, at +20° C., for 5 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 1.36 g of polyisoprene having a 3,4-cis atactic unit content of 67.0%: further characteristics of the procedure and of the polyisoprene obtained are reported in Table 1.

(94) FIG. 10 shows the FT-IR spectrum of the polyisoprene obtained.

(95) FIG. 11 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of the polyisoprene obtained.

Example 10

Synthesis of Butadiene-Isoprene Diblock Copolymer Formed Crystalline Polybutadiene (Hard Block)-Amorphous Polyisoprene (Soft Block) (Invention)

(96) 2 ml of 1,3-butadiene equal to 1.4 g in toluene solution (56.6 ml) and methylaluminoxane (MAO) in toluene solution (0.315 ml; 5×10.sup.−4 moles, equal to about 0.029 g) were loaded into a 100 ml test tube cooled to −20° C.: the solution obtained was brought to +40° C. and, subsequently, the Fe(bipy).sub.2Cl.sub.2 complex (1.1 ml of toluene solution at a concentration of 2 mg/ml; 5×10.sup.−6 moles, equal to about 2.2 mg) obtained as described in Example 3, was added. The whole was kept, under magnetic stirring, at +40° C., for 30 minutes and, subsequently, 2 ml of isoprene equal to about 1.36 g in toluene solution (8 ml) were added. The polymerization was left to proceed, under magnetic stirring, at +40° C., for a further 30 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 2.76 g of butadiene-isoprene diblock copolymer formed by a block of crystalline polybutadiene (hard block) having a 1,2 syndiotactic unit content of 65.0% and by a block of amorphous polyisoprene (soft block) having a 3,4 atactic unit content of 69.2%: further characteristics of the procedure and of the butadiene-isoprene diblock copolymer obtained are reported in Table 1.

(97) FIG. 12 shows the FT-IR spectrum of the butadiene-isoprene diblock copolymer obtained.

(98) FIG. 13 shows the phase images obtained through AFM—Atomic Force Microscopy—of the butadiene-isoprene diblock copolymer obtained.

Example 11

Synthesis of Butadiene-Isoprene Diblock Copolymer Formed by Crystalline Polybutadiene (Hard Block)-Amorphous Polyisoprene (Soft Block) (Invention)

(99) 3 ml of 1,3-butadiene equal to 2.1 g in toluene solution (56.6 ml) and methylaluminoxane (MAO) in toluene solution (0.315 ml; 5×10.sup.−4 moles, equal to about 0.029 g) were loaded into a 100 ml test tube cooled to −20° C.: the solution obtained was brought to +40° C. and, subsequently, the Fe(bipy).sub.2Cl.sub.2 complex (1.1 ml of toluene solution at a concentration of 2 mg/ml; 5×10.sup.−6 moles, equal to about 2.2 mg) obtained as described in Example 3, was added. The whole was kept, under magnetic stirring, at +40° C., for 30 minutes and, subsequently, 1 ml of isoprene equal to about 0.68 g in toluene solution (8 ml) was added: the polymerization was left to proceed, under magnetic stirring, at +40° C., for a further 45 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 2.78 g of butadiene-isoprene diblock copolymer formed by a block of crystalline polybutadiene (hard block) having a 1,2 syndiotactic unit content of 65.3% and by a block of amorphous polyisoprene (soft block) having a 3,4 atactic unit content of 69.5%: further characteristics of the procedure and of the butadiene-isoprene diblock copolymer obtained are reported in Table 1.

(100) FIG. 14 shows the FT-IR spectrum of the butadiene-isoprene diblock copolymer obtained.

Example 12

Synthesis of Butadiene-Isoprene Diblock Copolymer Formed by Crystalline Polybutadiene (Hard Block)-Amorphous Polyisoprene (Soft Block) (Invention)

(101) 1 ml of 1,3-butadiene equal to 0.7 g in toluene solution (56.6 ml) and methylaluminoxane (MAO) in toluene solution (0.315 ml; 5×10.sup.−4 moles, equal to about 0.029 g) were loaded into a 100 ml test tube cooled to −20° C.: the solution obtained was brought to +40° C. and, subsequently, the Fe(bipy).sub.2Cl.sub.2 complex (1.1 ml of toluene solution at a concentration of 2 mg/ml; 5×10.sup.−6 moles, equal to about 2.2 mg) obtained as described in Example 3, was added. The whole was kept, under magnetic stirring, at +40° C., for 45 minutes and, subsequently, 3 ml of isoprene equal to about 2.04 g in toluene solution (8 ml) were added: the polymerization was left to proceed, under magnetic stirring, at +40° C., for a further 60 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 2.76 g of butadiene-isoprene diblock copolymer formed by a block of crystalline polybutadiene (hard block) having a 1,2 syndiotactic unit content of 66.6% and by a block of amorphous polyisoprene (soft block) having a 3,4 atactic unit content of 73%: further characteristics of the procedure and of the butadiene-isoprene diblock copolymer obtained are reported in Table 1.

(102) FIG. 15 shows the FT-IR spectrum of the butadiene-isoprene diblock copolymer obtained.

(103) FIG. 16 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of the butadiene-isoprene diblock copolymer obtained.

Example 13

Synthesis of Butadiene-Isoprene Diblock Copolymer Formed by Crystalline Polybutadiene (Hard Block)-Amorphous Polyisoprene (Soft Block) (Invention)

(104) 2 ml of 1,3-butadiene equal to 1.4 g in toluene solution (57 ml) and methylaluminoxane (MAO) in toluene solution (0.315 ml; 5×10.sup.−4 moles. equal to about 0.029 g) were loaded into a 100 ml test tube cooled to −20° C.: the solution obtained was brought to +22° C. and, subsequently, the Fe(bipy)Cl.sub.2 complex (0.7 ml of toluene solution at a concentration of 2 mg/ml; 5×10.sup.−6 moles, equal to about 1.4 mg) obtained as described in Example 1, was added. The whole was kept, under magnetic stirring, at +22° C., for 75 minutes and, subsequently, 2 ml of isoprene equal to about 1.36 g in toluene solution (8 ml) were added: the polymerization was left to proceed, under magnetic stirring, at +22° C., for a further 60 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 2.76 g of butadiene-isoprene diblock copolymer formed by a block of crystalline polybutadiene (hard block) having a 1,2 syndiotactic unit content of 66.9% and by a block of amorphous polyisoprene (soft block) having a 3,4 atactic unit content of 68%: further characteristics of the procedure and of the butadiene-isoprene diblock copolymer obtained are reported in Table 1.

(105) FIG. 17 shows the FT-IR spectrum of the butadiene-isoprene diblock copolymer obtained.

(106) FIG. 18 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of the butadiene-isoprene diblock copolymer obtained.

Example 14

Synthesis of Butadiene-Isoprene Diblock Copolymer Formed by Crystalline Polybutadiene (Hard Block)-Amorphous Polyisoprene (Soft Block) (Invention)

(107) 1 ml of 1,3-butadiene equal to 0.7 g in toluene solution (57 ml) and methylaluminoxane (MAO) in toluene solution (0.315 ml; 5/10.sup.−4 moles, equal to about 0.029 g) was loaded into a 100 ml test tube cooled to −20° C.: the solution obtained was brought to +22° C. and, subsequently, the Fe(bipy)Cl.sub.2 complex (0.7 ml of toluene solution at a concentration of 2 mg/ml; 5×10 moles, equal to about 1.4 mg) obtained as described in Example 1, was added. The whole was kept, under magnetic stirring, at +22° C., for 60 minutes and, subsequently, 3 ml of isoprene equal to about 2.04 g in toluene solution (8 ml) were added: the polymerization was left to proceed, under magnetic stirring, at +22° C., for a further 75 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 2.74 g of butadiene-isoprene diblock copolymer formed by a block of crystalline polybutadiene (hard block) having a 1,2 syndiotactic unit content of 68.0% and by a block of amorphous polyisoprene (soft block) having a 3,4 atactic unit content of 68.7%: further characteristics of the procedure and of the butadiene-isoprene diblock copolymer obtained are reported in Table 1.

(108) FIG. 19 shows the FT-IR spectrum of the butadiene-isoprene diblock copolymer obtained.

Example 15

Synthesis of Butadiene-Isoprene Diblock Copolymer Formed by Crystalline Polybutadiene (Hard Block)-Amorphous Polyisoprene (Soft Block) (Invention)

(109) 2 ml of 1,3-butadiene equal to 1.4 g in toluene solution (56.5 ml) and methylaluminoxane (MAO) in toluene solution (0.315 ml; 5×10.sup.−4 moles, equal to about 0.029 g) were loaded into a 100 ml test tube cooled to −20° C.: the solution obtained was brought to 0° C. and, subsequently, the Fe(phen).sub.2Cl.sub.2 complex (1.2 ml of toluene solution at a concentration of 2 mg/ml; 5×10.sup.−6 moles, equal to about 2.4 mg) obtained as described in Example 4, was added. The whole was kept, under magnetic stirring, at 0° C., for 75 minutes and, subsequently, the temperature was brought to +22° C. and 2 ml of isoprene equal to about 1.36 g in toluene solution (8 ml) were added: the polymerization was left to proceed, under magnetic stirring, at +22° C., for a further 90 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 2.74 g of butadiene-isoprene diblock copolymer formed by a block of crystalline polybutadiene (hard block) having a 1,2 syndiotactic unit content of 71.8% and by a block of amorphous polyisoprene (soft block) having a 3,4 atactic unit content of 69.1%: further characteristics of the procedure and of the butadiene-isoprene diblock copolymer obtained are reported in Table 1.

(110) FIG. 20 shows the FT-IR spectrum of the butadiene-isoprene diblock copolymer obtained.

Example 16

Synthesis of Butadiene-Isoprene Diblock Copolymer Formed by Crystalline Polybutadiene (Hard Block)-Amorphous Polyisoprene (Soft Block) (Invention)

(111) 3 ml of 1,3-butadiene equal to 1.4 g in toluene solution (56.5 ml) and methylaluminoxane (MAO) in toluene solution (0.315 ml; 5×10.sup.−4 moles, equal to about 0.029 g) were loaded into a 100 ml test tube cooled to −20° C.: the solution obtained was brought to 0° C. and, subsequently, the Fe(phen).sub.2Cl.sub.2 complex (1.2 ml of toluene solution at a concentration of 2 mg/ml; 5×10.sup.−6 moles, equal to about 2.4 mg) obtained as described in Example 4, was added. The whole was kept, under magnetic stirring, at 0° C., for 75 minutes and, subsequently, the temperature was brought to +22° C. and 1 ml of isoprene equal to about 0.68 g in toluene solution (8 ml) was added: the polymerization was left to proceed, under magnetic stirring, at +22° C., for a further 90 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 2.08 g of butadiene-isoprene diblock copolymer formed by a block of crystalline polybutadiene (hard block) having a 1,2 syndiotactic unit content of 72.9% and by a block of amorphous polyisoprene (soft block) having a 3,4 atactic unit content of 68.9%: further characteristics of the procedure and of the butadiene-isoprene diblock copolymer obtained are reported in Table 1.

(112) FIG. 21 shows the FT-IR spectrum of the butadiene-isoprene diblock copolymer obtained.

(113) FIG. 22 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of the butadiene-isoprene diblock copolymer obtained.

(114) FIG. 23 shows the phase images obtained through AFM—Atomic Force Microscopy—of the butadiene-isoprene diblock copolymer obtained.

Example 17

Synthesis of Butadiene Isoprene Diblock Copolymer Formed by Crystalline Polybutadiene (Hard Block)-Amorphous Polyisoprene (Soft Block) (Invention)

(115) 2 ml of 1,3-butadiene equal to 1.4 g in toluene solution (56.9 ml) and methylaluminoxane (MAO) in toluene solution (0.315 ml; 5×10.sup.−4 moles, equal to about 0.029 g) were loaded into a 100 ml test tube cooled to −20° C.: the solution obtained was brought to −20° C. and, subsequently, the Fe(bipy)Cl.sub.2 complex (0.75 ml of toluene solution at a concentration of 2 mg/ml; 5×10.sup.6 moles, equal to about 1.5 mg) obtained as described in Example 2, was added. The whole was kept, under magnetic stirring, at −20° C., for 90 minutes and, subsequently, the temperature was brought to +22° C. and 2 ml of isoprene equal to about 1.36 g in toluene solution (8 ml) were added. The polymerization was left to proceed, under magnetic stirring, at +22° C., for a further 120 minutes: the polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 2/6 g of butadiene-isoprene diblock copolymer formed by a block of crystalline polybutadiene (hard block) having a 1,2 syndiotactic unit content of 79.0% and by a block of amorphous polyisoprene (soft block) having a 3,4 atactic unit content of 69.9%: further characteristics of the procedure and of the butadiene-isoprene diblock copolymer obtained are reported in Table 1.

(116) FIG. 24 shows the FT-IR spectrum of the butadiene-isoprene diblock copolymer obtained.

Example 18

Synthesis of Butadiene-Isoprene Diblock Copolymer Formed by Crystalline Polybutadiene (Hard Block)-Amorphous Polyisoprene (Soft Block) (Invention)

(117) ml of 1,3-butadiene equal to 0.7 g in toluene solution (56.9 ml) and methylaluminoxane (MAO) in toluene solution (0.315 ml; 5×10.sup.−4 moles, equal to about 0.029 g) was loaded into a 100 ml test tube cooled to −20° C.: the solution obtained was brought to −20° C. and, subsequently, the Fe(bipy)Cl.sub.2 complex (0.75 ml of toluene solution at a concentration of 2 mg/ml; 5×10.sup.−6 moles, equal to about 1.5 mg) obtained as described in Example 2, was added. The whole was kept, under magnetic stirring, at −20° C., for 120 minutes and, subsequently, the temperature was brought to +22° C. and 3 ml of isoprene equal to about 2.04 g in toluene solution (8 ml) were added: the polymerization was left to proceed, under magnetic stirring, at +22° C., for a further 180 minutes. The polymerization was then stopped by adding 2 ml of methanol containing some drops of hydrochloric acid. The polymer obtained was then coagulated by adding 40 ml of a methanol solution containing 4% of Irganox® 1076 antioxidant (Ciba) obtaining 2.74 g of butadiene-isoprene diblock copolymer formed by a block of crystalline polybutadiene (hard block) having a 1,2 syndiotactic unit content of 77.6% and by a block of amorphous polyisoprene (soft block) having a 3,4 atactic unit content of 71.2%: further characteristics of the procedure and of the butadiene-isoprene diblock copolymer obtained are reported in Table 1.

(118) FIG. 25 shows the FT-IR spectrum of the butadiene-isoprene diblock copolymer obtained.

(119) FIG. 26 shows the .sup.1H-NMR (bottom) and .sup.13C-NMR (top) spectra of the butadiene-isoprene diblock copolymer obtained.

Example 19

Preparation of a Mechanical Mixture of Crystalline 1,2 Syndiotactic Polybutadiene and Amorphous 3,4 Atactic Polyisoprene (Comparative)

(120) 1.54 g of crystalline polybutadiene having a 1,2 syndiotactic unit content of 77.4% obtained as described in Example 7, 0.45 g of amorphous polyisoprene having a 3,4 atactic unit content of 67.0% obtained as described in Example 9 and 50 ml of toluene were placed in a 100 ml test tube: the whole was maintained, under magnetic stirring, for 120 minutes, until complete solubilization of the two polymers, i.e. until a perfectly homogeneous solution was obtained. To the solution thus obtained, methanol in great excess (200 ml) was added, obtaining the precipitation of a solid product that was recovered through filtration and vacuum dried, at room temperature, for one night.

(121) FIG. 27 shows the phase images obtained through AFM—Atomic Force Microscopy—of the mechanical mixture of crystalline 1,2 syndiotactic polybutadiene and amorphous 3,4 atactic polyisoprene obtained.

Example 20

Extraction in Diethylether of Butadiene-Isoprene Diblock Copolymer Formed by Crystalline Polybutadiene (Hard Block)-Amorphous Polyisoprene (Soft Block)

(122) 2 grams of butadiene isoprene diblock copolymer formed by crystalline polybutadiene (hard block)-amorphous polyisoprene (soft block) obtained as described in Example 10, were continuously extracted for about 3 hours, with boiling diethylether (100 ml). At the end of the extraction the ether solution containing one part of the butadiene-isoprene diblock copolymer (soluble fraction in diethylether) was reduced in volume (to about 20 ml), then excess methanol was added (about 100 ml) so as to obtain the coagulation and precipitation of the dissolved copolymer: the whole was filtered and the residue on the filter was vacuum dried, at room temperature for one night, obtaining 0.770 g (yield 38.5% relative to the copolymer loaded) of copolymer.

(123) The residue not extracted was in turn recovered, and then vacuum dried, at room temperature for one night, obtaining 1.230 g (yield 61.5% relative to the copolymer loaded) of copolymer.

(124) The two fractions were examined through infra-red spectroscopy (FT-IR), highlighting a very similar structure, confirming the fact that the polymer material obtained is effectively a copolymer, and not a mixture of homopolymers.

(125) TABLE-US-00001 TABLE 1 Copolymerization of 1,3-butadiene and isoprene with catalytic systems comprising iron complexes PB.sup.(3) block PI.sup.(4) block (Co)polymer microstructure microstructure Conversion composition cis-1,4 1,2 [rr].sup.(8) cis-14 3,4 T.sub.m.sup.(5) T.sub.c.sup.(6) T.sub.g.sup.(7) M.sub.w Example (%) B.sup.(1) I.sup.(2) (%) (%) (%) (%) (%) (° C.) (° C.) (° C.) (g/mol) M.sub.w/M.sub.n 5 100 100 — 35.4 64.6 71.5 — — 73.9 49.9 — 423700 2.1 6 100 100 — 31.7 68.3 73.0 — — 93.0 72.1 — 556100 2.5 7 100 100 — 22.6 77.4 77.8 — — 100 89.8 — 629100 2.1 8 100 100 — 16.8 83.2 82.0 — — 115 101.9 — 856300 2.6 9 100 — 100 — — — 33.0 67.0 — — −49.8 211910 1.6 10 100 56.5 43.5 35.0 65.0 65.9 30.8 69.2 70.9 57.2 −42.5 681400 2.4 11 100 79.6 20.4 34.7 65.3 66.7 30.5 69.5 76.6 70.7 −55.3 693000 2.0 12 100 30.2 69.8 33.4 66.6 67.0 27.0 73.0 72.4 60.1 −51.6 654000 2.1 13 100 56.5 43.5 33.1 66.9 69.8 32.0 68.0 86.3 68.2 −48.2 829100 2.3 14 100 30.2 69.8 32.0 68.0 70.1 31.3 68.7 85.9 69.7 −41.5 801500 2.6 15 100 30.2 69.8 28.2 71.8 75.9 30.9 69.1 118.7 105.1 45.7 857600 2.1 16 100 79.6 20.4 27.1 72.9 76.2 31.1 68.9 118.7 107.2 −44.5 894500 2.2 17 100 56.5 43.5 21.0 79.0 79.7 30.1 69.9 121.8 111.3 −46.1 1216800 2.4 18 100 30.2 69.8 22.4 77.6 80.3 28.8 71.2 120.2 109.7 −45.0 954760 2.3 .sup.(1)B = 1,3-butadiene; .sup.(2)I = isoprene; .sup.(3)PB = polybutadiene; .sup.(4)PI = polyisoprene; .sup.(5)T.sub.m = melting point; .sup.(6)T.sub.c = crystallization temperature; .sup.(7)T.sub.g = glass transition temperature; .sup.(8)[rr] = content of syndiotactic triads in the block of polybutadiene with a 1,2 syndiotactic structure determined through .sup.13C-NMR analysis;

(126) In Table 1: the melting point (T.sub.m) in Examples 5-8 refers to homopolymer polybutadiene; the melting point (T.sub.m) in Examples 10-18 refers to the block of crystalline polybutadiene (hard block); the crystallization temperature (T.sub.c) in Examples 5-8 refers to homopolymer polybutadiene; the crystallization temperature (T.sub.c) in Examples 10-18 refers to the block of crystalline polybutadiene (hard block); the glass transition temperature (T.sub.g) in Examples 9 refers to homopolymer polyisoprene;

(127) the glass transition temperature (T.sub.g) in Examples 10-18 refers to the block of amorphous polyisoprene (soft block).