TRIBLOCK COPOLYMER AND PROCESS FOR PREPARATION THEREOF

Abstract

Provided is a triblock copolymer comprising a poly(3-hydroxypropionate) block, and polylactide blocks bonded to both ends of the poly(3-hydroxypropionate) block. Also provided is a method for preparing a triblock copolymer by ring-opening polymerization of lactide monomers in the presence of a poly(3-hydroxypropionate) initiator having hydroxy groups at both ends.

Claims

1. A triblock copolymer comprising: a poly(3-hydroxypropionate) block of the following Chemical Formula 1; and a polylactide block bonded to both ends of the poly(3-hydroxypropionate) block, respectively, ##STR00011## wherein in Chemical Formula 1: D is a substituted or unsubstituted C.sub.1-10 alkylene; a substituted or unsubstituted C.sub.6-60 arylene; or a substituted or unsubstituted C.sub.2-60 heteroarylene containing at least one heteroatom selected from the group consisting of O, N, Si and S; R.sub.1 to R.sub.4 are each independently hydrogen, halogen, hydroxy, cyano, nitrile, nitro, amino, a substituted or unsubstituted C.sub.1-60 alkyl, a substituted or unsubstituted C.sub.1-60 haloalkyl, a substituted or unsubstituted C.sub.1-60 thioalkyl, a substituted or unsubstituted C.sub.1-60 alkoxy, a substituted or unsubstituted C.sub.1-60 hal oalkoxy, a substituted or unsubstituted C.sub.3-60 cycloalkyl, a substituted or unsubstituted C.sub.1-60 alkenyl, a substituted or unsubstituted C.sub.6-60 aryla substituted or unsubstituted C.sub.6-60 aryloxy, or a substituted or unsubstituted C.sub.2-60 heteroaryl containing at least one of O, N, Si and Stand S, and n and m are each independently an integer from 1 to 10000.

2. The triblock copolymer according to claim 1, wherein: the triblock copolymer comprises 0.01 to 100% by weight of the poly(3-hydroxypropionate) block of Chemical Formula 1.

3. The triblock copolymer according to claim 1, wherein: the triblock copolymer has a weight average molecular weight of 10,000 to 400,000.

4. A method for preparing a triblock copolymer, comprising subjecting a lactide monomer to a ring-opening polymerization in the presence of a poly(3-hydroxypropionate) initiator having hydroxy groups at both ends of the following Chemical Formula 2 to prepare a triblock copolymer: ##STR00012## wherein in the Chemical Formula 2:Formula 2, D is a substituted or unsubstituted C.sub.1-10 alkylene, a substituted or unsubstituted C.sub.6-60 arylene, or a substituted or unsubstituted C.sub.2-60 heteroarylene containing at least one heteroatom selected from the group consisting of O, N, Si and S, R.sub.1 to R.sub.4 are each independently hydrogen, halogen, hydroxyl, cyano, nitrile, nitro, amino, a substituted or unsubstituted C.sub.1-60 alkyl, a substituted or unsubstituted C.sub.1-60 haloalkyl, a substituted or unsubstituted C.sub.1-60 thioalkyl, a substituted or unsubstituted C.sub.1-60 alkoxy, a substituted or unsubstituted C.sub.1-60 haloalkoxy, a substituted or unsubstituted C.sub.3-60 cycloalkyl, a substituted or unsubstituted C.sub.1-60 alkenyl, a substituted or unsubstituted C.sub.6-60 aryl, a substituted or unsubstituted C.sub.6-60 aryloxy, or a substituted or unsubstituted C.sub.2-60 heteroaryl containing at least one of O, N, Si and S, and n and m are each independently an integer from 1 to 10000.

5. The method for preparing a triblock copolymer according to claim 4, wherein: the poly(3-hydroxypropionate) initiator having hydroxy groups at both ends has a weight average molecular weight of 5,000 to 50,000.

6. The method according to claim 4, wherein: the poly(3-hydroxypropionate) initiator having hydroxy groups at both ends is present in an amount of 0.01 to 100 parts by weight, based on 100 parts by weight of the lactide monomer.

7. The method according to claim 4, further comprising: subjecting 3-hydroxypropionate to condensation polymerization to prepare a poly(3-hydroxypropionate) oligomer; and reacting the poly(3-hydroxypropionate) oligomer with one or more compounds selected from the group consisting of bisoxazoline-based compounds and diol-based compounds to prepare the poly(3-hydroxypropionate) initiator having hydroxy groups at both ends.

8. The method according to claim 7, wherein: the bisoxazoline-based compound has the following Chemical Formula 3: ##STR00013## wherein in Chemical Formula 3: D is a substituted or unsubstituted C.sub.1-10 alkylene; a substituted or unsubstituted C.sub.6-60 arylene; or a substituted or unsubstituted C.sub.2-60 heteroarylene containing at least one heteroatom selected from the group consisting of O, N, Si and S; R.sub.1 to R.sub.4 are each independently hydrogen, halogen, hydroxyl, cyano, nitrile, nitro, amino, a substituted or unsubstituted C.sub.1-60 alkyl, a substituted or unsubstituted C.sub.1-60 haloalkyl, a substituted or unsubstituted C.sub.1-60 thioalkyl, a substituted or unsubstituted C.sub.1-60 alkoxy, a substituted or unsubstituted C.sub.1-60 haloalkoxy, a substituted or unsubstituted C.sub.3-60 cycloalkyl, a substituted or unsubstituted C.sub.1-60 alkenyl, a substituted or unsubstituted C.sub.6-60 aryl, a substituted or unsubstituted C.sub.6-60 aryloxy, or a substituted or unsubstituted C.sub.2-60 heteroaryl containing at least one of O, N, Si and S; and n and m are each independently an integer from 1 to 10000.

9. The method according to claim 4, wherein: the ring-opening polymerization is performed in the presence of one or more catalysts selected from the group consisting of an organometallic complex catalyst and an organic catalyst.

10. The method according to claim 9, wherein: the organometallic complex catalyst is a catalyst of the following Chemical Formula 4:
MA.sup.1.sub.pA.sup.2.sub.2−p   Chemical Formula 4 wherein in Chemical Formula 4: M is Al, Mg, Zn, Ca, Sn, Fe, Y, Sm, Lu, Ti or ZuZr, p is an integer from 0 to 2; and A.sup.1 and A.sup.2 are each independently an alkoxy or carboxyl group.

11. The method according to claim 10, wherein: the MA.sup.1.sub.pA.sup.2.sub.2−p is tin (II) 2-ethylhexanoate (Sn(Oct).sub.2).

12. The method for preparing a triblock copolymer according to claim 9, wherein: the one or more catalysts is present in an amount of 0.01 to 10 mol % based on 100 mol % of the lactide monomer.

13. The method for preparing a triblock copolymer according to claim 4, wherein: the ring-opening polymerization is performed at 150 to 200° C. for 5 to 10 hours.

14. The method according to claim 4, wherein: the ring-opening polymerization is performed by bulk polymerization.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0068] FIG. 1a is a graph showing the results of NMR analysis of the polymer prepared in Comparative Example 1, and FIG. 1b is a graph showing the results of NMR analysis of the triblock copolymer prepared in Example 3.

EXAMPLES

[0069] Hereinafter, the present disclosure will be described in more detail by way of examples. However, the following examples are for illustrative purposes only, and the contents of the present disclosure are not limited thereby.

Examples 1 to 4

[0070] (1) Preparation of Poly(3-hydroxypropionate) Initiator Having Hydroxy Groups at Both Ends

[0071] 7 g (77.71 mmol) of 3-hydroxypropionate was dried, and then subjected to condensation polymerization in the presence of p-toluene sulfonic acid (p-TSA) catalyst at a temperature of 130° C. for 24 hours to prepare a poly(3-hydroxypropionate) oligomer (weight average molecular weight of 4,150).

[0072] 4 g (1.65 mmol) of the prepared poly(3-hydroxypropionate) oligomer and 0.28 g (1.32 mmol) of 1,4-phenylenebisoxazoline (1,4-PBO) were added to a 250 mL round flask, and reacted at 110° C. for 30 minutes to prepare a poly(3-hydroxypropionate) initiator (weight average molecular weight of 10,100) having hydroxy groups at both ends of the following Chemical Formula 5:

##STR00010##

[0073] (2) Preparation of Triblock Copolymer

[0074] To a 500 mL round flask, L-lactide, poly(3-hydroxypropionate) initiator of Chemical Formula 5 having hydroxy groups at both ends, and tin(II) 2-ethylhexanoate were added in the amounts shown in Table 1 below, and vacuum-dried at room temperature for 4-5 hours by applying a vacuum sufficiently.

[0075] Subsequently, the flask was placed in an oil bath pre-heated to 130° C., the temperature of which was raised to 180° C., and then the ring-opening polymerization reaction was carried out for 20 minutes. After the reaction was completed, the reaction product was dissolved in chloroform and then extracted with methanol to recover the block copolymer.

TABLE-US-00001 TABLE 1 Tin(II) 2- Initiator of (unit: g) L-lactide ethylhexanoate Chemical Formula 5 Example 1 16.00 0.02 0.16 Example 2 16.00 0.02 0.80 Example 3 16.00 0.02 1.60 Example 4 16.00 0.02 0.48

Comparative Examples 1 and 2

[0076] To a 500 mL round flask, L-lactide, dodecanol, and tin(II) 2-ethylhexanoate were added in the amounts shown in Table 2 below, and vacuum-dried at room temperature for 4-5 hours by applying a vacuum sufficiently.

[0077] Subsequently, the flask was placed in an oil bath pre-heated to 130° C., the temperature of which was raised to 180° C., and then a ring-opening polymerization reaction was carried out for 20 minutes. After the reaction was completed, the reaction product was dissolved in chloroform and then extracted with methanol to recover the polymer.

TABLE-US-00002 TABLE 2 Tin(II) 2- (unit: g) L-lactide ethylhexanoate Dodecanol Comparative 16.00 0.02 0.01 Example 1 Comparative 16.00 0.02 0.02 Example 2

[0078] Evaluation

[0079] 1. NMR (Nuclear Magnetic Resonance) Analysis

[0080] NMR analysis was performed at room temperature using an NMR spectrometer including a Varian Unity Inova (500 MHz) spectrometer having a triple resonant 5 mm probe. The block copolymers and polymers prepared in Examples 1 to 4 and Comparative Example 1, respectively, were diluted to a concentration of about 10 mg/ml and used as an analysis target material in a solvent for NMR measurement (CDC13), and chemical shifts were expressed in ppm.

[0081] FIG. 1a is a graph showing the results of NMR analysis of the polymer prepared in Comparative Example 1, and FIG. 1b is a graph showing the results of NMR analysis of the triblock copolymer prepared in Example 3. On the other hand, according to FIG. 1a and FIG. lb, it was confirmed that the NMR analysis graph of the block copolymer of Example 3 shows a poly(3-hydroxypropionate) peak, unlike the NMR analysis graph of the polymer of Comparative Example 1.

[0082] In addition, the integration ratio of the poly(3-hydroxypropionate) peak was calculated from the graphs of the NMR analysis results of Examples 1 to 4, which is shown in the “content of poly(3-hydroxypropionate) analyzed by NMR” in Table 3 below.

TABLE-US-00003 TABLE 3 Example 1 Example 2 Example 3 Example 4 Content of initiator of 0.160 g 0.800 g 1.600 g 0.480 g Chemical Formula 5 actually used Content of poly(3- 0.224 g 1.120 g 1.760 g 0.752 g hydroxypropionate) analyzed by NMR

[0083] According to Table 3, Examples 1, 2 and 4 also showed a poly(3-hydroxypropionate) peak in NMR analysis, as in Example 3. In particular, it can be predicted that the initiator used in the method for preparing the block copolymer of Examples 1 to 4 was mostly used as the reactant.

[0084] 2. GPC (Gel Permeation Chromatography) Analysis

[0085] The weight average molecular weight (Mw) and number average molecular weight (Mn) of the block copolymers of Examples 1 to 4 and the polymers of Comparative Examples 1 and 2 were determined by gel permeation chromatography (GPC) (Waters: Waters707). The block copolymer/polymer to be measured was dissolved in chloroform to a concentration of 4000 ppm, and 100 μl was injected into GPC. Chloroform was used as the mobile phase of GPC, the flow rate was 1.0 mL/min, and the analysis was performed at 35° C. The column connected four Waters HR-05,1,2,4E in series. RI and PAD Detector was used as the detector, and the measurement was performed at 35° C.

TABLE-US-00004 TABLE 4 Number Weight average average Poly- molecular molecular dispersity weight weight Index Mn.sub.theoretical (Mn) (Mw) (PDI) Example 1 163,474 90,200 123,000 1.36 Example 2 33,991 59,100 82,300 1.39 Example 3 17,805 48,700 63,100 1.30 Example 4 55,763 86,300 131,000 1.52 Comparative 288,186 91,731 180,524 1.97 Example 1 Comparative 144,186 55,984 115,050 2.06 Example 2

[0086] According to Table 4, it was confirmed that dodecanol was used as an initiator in Comparative Examples 1 and 2, and that as the content of dodecanol increased, the number average molecular weight and the weight average molecular weight of the polymer decreased. Similarly, it was confirmed that in Examples 1 to 4, as the content of poly(3-hydroxypropionate) disclosed in Table 1 increased, the number average molecular weight and weight average molecular weight of the block copolymer decreased, so that poly (3-hydroxypropionate) acts as an initiator.

[0087] 3. Measurement of Tensile Elongation

[0088] The polymers obtained in Examples 2, 4 and Comparative Example 1 were used, and a Hot-press (Limotem QM900S) device was used to prepare a dogbone shaped test specimen corresponding to ASTM D638 Type V at 170° C.

[0089] The tensile elongation of the film was measured according to the measurement method of IPC-TM-650 using a tensile strength meter (manufacturer: Instron, model name: 3345 UTM) for the prepared test specimen.

TABLE-US-00005 TABLE 5 Comparative Example 2 Example 4 Example 1 Tensile 80 13.5 2.5 elongation (%)

[0090] According to Table 5, it was confirmed that the copolymers of Examples 2 and 4, in which L-lactide was subjected to a ring-opening polymerization in the presence of a poly(3-hydroxypropionate) initiator, exhibited a remarkably higher tensile elongation than Comparative Example 1, in which L-lactide was subjected to a ring opening polymerization in the presence of dodecanol.