Compositions comprising polyacrylate-polysilane block copolymers

Abstract

The present invention provide a composition comprising: a polyacrylate-polysilane block copolymer of structure (I) and an organic polymer which is different from the block copolymer of formula (I) wherein m and n independent of one another, are integers ranging from 2 to 4000; p is an integer ranging from 0 to 5; q is an integer ranging from 1 to 5; R.sub.1 represents hydrogen, straight-chain or branched alkyl group having 1 to 4 carbon atoms; R.sub.2 represents hydrogen, straight-chain or branched alkyl group having 1 to 18 carbon atoms; R.sub.3 represents hydrogen, hydroxyl group, straight-chain or branched alkyl group having 1 to 4 carbon atoms, or an C.sub.6-C.sub.14-aryl group; L is a single bond or a bivalent group NH, C(O)NH, NHC(O)NH, OC(O)NH or CH.sub.2; R.sup.4, R.sup.5 and R.sup.6 independent of one another, represent hydrogen, straight-chain or branched alkyl group having 1 to 8 carbon atoms or a polydimethylsiloxane residue; and R.sup.7 represents hydrogen or methyl group. ##STR00001##

Claims

1. A composition comprising: a polyacrylate-polysilane block copolymer of structure (I) and an organic polymer which is different from the block copolymer of formula (I): ##STR00004## wherein m and n independent of one another, are integers ranging from 2 to 4000; p is an integer ranging from 0 to 5; q is an integer ranging from 1 to 5; R.sup.1 represents hydrogen, straight-chain or branched alkyl group having 1 to 4 carbon atoms; R.sup.2 represents hydrogen, straight-chain or branched alkyl group having 1 to 18 carbon atoms; R.sup.3 represents hydrogen, hydroxyl group, straight-chain or branched alkyl group having 1 to 4 carbon atoms, or an C.sub.6-C.sub.14-aryl group; L is a single bond or a bivalent group NH, C(O)NH, NHC(O)NH, OC(O)NH or CH.sub.2; R.sup.4, R.sup.5 and R.sup.6 independent of one another, represent hydrogen, straight-chain or branched alkyl group having 1 to 8 carbon atoms or a polydimethylsiloxane residue; and R.sup.7 represents hydrogen or methyl group.

2. The composition of claim 1, wherein at least one of R.sup.4, R.sup.5 and R.sup.6 represents a polydimethylsiloxane group.

3. The composition of claim 1, wherein R.sup.3 represents hydrogen, R.sup.7 represents methyl group and wherein at least one of R.sup.4, R.sup.5 and R.sup.6 represents a polydimethylsiloxane group.

4. The composition of claim 1, wherein L represents methylene (CH.sub.2) group and wherein at least one of R.sup.4, R.sup.5 and R.sup.6 represents a polydimethylsiloxane group.

5. The composition of claim 1, wherein L represents amine (NH) group, amide (C(O)NH) group, urea (NHC(O)NH) group, or urethane (OC(O)NH) group and wherein at least one of R.sup.4, R.sup.5 and R.sup.6 represents a polydimethylsiloxane group.

6. The composition as claimed in claim 1, wherein m is an integer ranging from 100 to 1000; n is an integer ranging from 100 to 1000, p is an integer ranging from 0 to 3 and q is an integer ranging from 1 to 3.

7. The composition as claimed in claim 1, wherein the weight ratio of the polyacrylate block (A) to the polysilane block (B) is in the range of about 1:1.810.sup.7 to 6204:1.

8. The composition as claimed in claim 1, wherein the number average molecular weight of the polydimethylsiloxane group is in the range of about 500 g/mole to about 300,000 g/mole.

9. The composition as claimed in claim 1, wherein the organic polymer comprises at least one of polyolefins, polyoxides, polyesters, polystyrene, polylactic acid, cellulose, acrylonitrile-butadiene- styrene (ABS), polyamide, polycarbonate, alkyd resins, amino resins, phenol resins, polyurethane resins, epoxy resins, melamine-urethane-formaldehyde resins, urethane-formaldehyde resins, melamine resins and acrylate resins.

10. The composition of claim 9, wherein the organic polymer is a polypropylene.

11. The composition as claimed in claim 1, wherein the polyacrylate-polysilane block copolymer is present in the composition in an amount of from about 0.5 to about 90% by weight of the total weight of the composition.

12. The composition of claim 11, wherein the polyacrylate-polysilane block copolymer is present in the composition in an amount of from about 5% to about 90%.

13. An article prepared from the composition as claimed in claim 1, wherein the article is a molded article or an extruded article.

14. The article of claim 13, wherein the article is an automotive part.

Description

EXAMPLES

Example 1

(1) a) Synthesis of Silane Polymer:

(2) A three-necked round bottom (RB) flask was attached with a condenser and a Schlenk line for purging with nitrogen. The RB flask was placed over a stirrer and a hot plate with heat on block. Nitrogen gas was flushed through preheated and dried RB flask to remove any moisture content prior to polymerization.

(3) About 10 grams of methacryloxypropyltrimethoxysilane was taken in the RB flask and temperature was raised to 63 C. Azobisisobutyronitrile (AIBN) (0.04 g) was added dropwise into the RB flask. The onset of the reaction is marked with increase in viscosity of the reaction mixture. The heating and stirring was continued for another 2 hours. The reaction mixture was cooled down.

(4) b) Synthesis of Acrylate Polymer

(5) About 40 grams methyl methacrylate (MMA) along with 100 millilitres (mL) of tetrahydrofuran (THF) was taken in a three-necked RB flask which has been purged with nitrogen. The temperature of the reaction mixture was raised to 60 C. Nitrogen atmosphere was maintained through the Schlenk line. After the temperature was attained, 0.16 g of azobisisobutyronitrile (AIBN) was added to the reaction mixture. The onset of the reaction is marked by solids formation. The reaction was continued for 1 hour. A sample was withdrawn from the reaction mixture after 1 hour for further characterization. The acrylate polymer obtained from this Example was characterized using NMR. The NMR data 1H NMR (400 MHz, CDCl3) 3.7-3.5 [COOCH3], 2.0 1.5 [C(CH3)CH2], 1.5-0.5 [C(CH3)CH2] confirms the formation of the polymer. The molecular weight analysis was performed in chloroform solvent using GPC with polystyrene standards and is listed in Table 1. The acrylate polymer has a weight average molecular weight (Mw) of 209,000, a number average molecular weight (Mn) of 73,000 g/mole and a polydispersity of 2.8.

(6) c) Synthesis of Block Copolymer:

(7) About 1.6 g of reaction mixture containing silane polymer of Example 1a was taken under inert atmosphere and added to the flask of Example 1 b. The reaction was continued for further 1 hour and then about 10 g of polydimethylsiloxane (PDMS Mn 500 g/mole) was added to the RB flask along with 0.2 g of dibutyltin dilaurate (DBTDL). The reaction was continued for further 2 hours and precipitated out in excess methanol. The resulting product was then filtered and dried in vacuum oven at 40 C. for 24 hours to remove traces of methanol from the product. The block copolymer product thus obtained was then weighed to get a yield of 89% and used for further characterisation. The block copolymer formation is confirmed by NMR from the appearance of peak at 0.3-0.0 corresponding to [SiCH.sub.3]. The molecular weight analysis of block copolymer was performed in chloroform solvent using GPC with polystyrene standards and is listed in Table 1. The block copolymer has a weight average molecular weight (Mw) of 240,000, a number average molecular weight (Mn) of 105,000 and a polydispersity of 2.3 as shown in Table 1.

(8) TABLE-US-00001 TABLE 1 GPC data of acrylate and block copolymers Mw Mn Example (g/mole) (g/mole) Polydispersity 1b 209,000 73,000 2.8 1c 240,000 105,000 2.3

(9) Tg of the polymer was recorded using DSC (Perkin Elmer DSC 6000) at a heating rate of 10 C/min. The block copolymer exhibits two Tg, the first Tg corresponding to PDMS appear at around 50 C. to 70 C. and the second Tg corresponding to acrylate appear between 140 C. and 150 C.

(10) The TGA (Thermogravimetric Analysis) of the block copolymer was measured using Perkin Elmer TGA 4000 to know the degradation temperature. A sample of the block copolymer was heated under nitrogen atmosphere and the heating was continued to a temperature of up to 700 C. at the rate of 20 C. per minute. The TGA of the block copolymer shows onset of degradation at a temperature of 250 C. which indicates the suitability of these block polymers in conventional polymer processing methods.

Example 2

(11) Preparation of polypropylene compositions: The polyacrylate-polysilane block copolymer (PPBC) of Example 1c was blended with polypropylenes (PP) to form compositions 2a-2d as shown in Table 2. The polypropylenes, polypropylene copolymer (Repol MI3530) and polypropylene homopolymer were procured from Reliance Industries Limited (RIL). The compositions were twin screw extruded using a twin screw extruder (Swastik, India) to form granules. The granules were injection moulded using an injection moulding machine (Arburg, Germany) to form sample moulded sheets (2a-2d) with dimensions of 4.58.50.2 centimeter (cm) having textured surface on one side. Similarly, blank moulded sheets were also prepared without adding polyacrylate-polysilane block copolymer to polypropylene for comparison.

Example 3

(12) Preparation of polystyrene compositions: The polyacrylate-polysilane block copolymer (PPBC) of Example 1c with varying weight percent was mixed with polystyrene (PS) granules (GPPS SC 206, RIL) to form compositions 3a-3c as shown in Table 3. The compositions were injection moulded using an injection moulding machine (Arburg) to form sample moulded sheets (3a-3c) with dimensions of 4.58.50.2 cm having textured surface on one side. Similarly, a blank moulded sheet was also prepared without adding polyacrylate-polysilane block copolymer to PS for comparison.

Example 4

(13) Preparation of Polyethylene terephthalate (PET) compositions: The polyacrylate-polysilane block copolymer (PPBC) of Example 1c with varying weight percent was mixed with PET granules (Relpet, RIL) to form compositions 4a-4b as shown in Table 4. The compositions were injection moulded using an injection moulding machine (Arburg) to form sample moulded sheets (4a-4b) with dimensions of 4.58.50.2 cm having textured surface on one side. Similarly, a blank moulded sheet was also prepared without adding polyacrylate-polysilane block copolymer to PET for comparison.

Example 5

(14) Scratch resistance test (ASTM D3363-00): The moulded sheets of Examples 2 to 4 were evaluated for scratch resistance using pencils of hardness 3H and 4H, respectively. The blank sheets as well as sample sheets were scratched and the resulting scratches on the surfaces were evaluated visually as well as by using an Optical microscope (Olympus BX-51). The width and impression of the scratches on the surfaces were compared and accordingly rated as having passed (P) or failed (F) the tests and for which the data was not available is marked as N.A. The results of the tests are given along with the compositions in Tables 2, 3 and 4. The minimum industry requirement for scratch resistance is to have passed a 3H pencil scratch resistance test. The scratch resistance tests confirm the utility of the polyacrylate-polysilane block copolymer as scratch resistance additive for polymers.

(15) TABLE-US-00002 TABLE 2 Polypropylene compositions PPBC PP copolymer PP homopolymer Sample no. (weight percent) (weight percent) (weight percent) 3H 4H 2a 1 96 3 P P 2b 2 95 3 P P 2c 1 99 0 P F 2d 2 98 0 P P

(16) TABLE-US-00003 TABLE 3 Polystyrene compositions PPBC PS Sample no. (weight percent) (weight percent) 3H 4H 3a 0.5 99.5 P F 3b 1 99 P P 3c 2 98 P P

(17) TABLE-US-00004 TABLE 4 PET compositions PPBC PET Sample no. (weight percent) (weight percent) 3H 4H 4a 1 99 N.A P 4b 2 98 P P