BLOCK COPOLYMER AND METHOD FOR PREPARATION THEREOF`

Abstract

Provided is a block copolymer of Formula 1:

##STR00001##

wherein in Formula 1: R.sub.1 and R.sub.2 are each independently hydrogen, N, O, S, or substituted or unsubstituted C.sub.1-20 alkyl: X.sub.1 and X.sub.2 are each independently a direct bond, COO, NRCO, (NR)(COO), RNCONR, or OCOO, wherein the R's are each independently hydrogen or C.sub.1-20 alkyl; L is a direct bond, substituted or unsubstituted C.sub.1-10 alkylene, substituted or unsubstituted C.sub.6-60 arylene, or substituted or unsubstituted C.sub.2-60 heteroarylene containing one or more heteroatoms selected from the group consisting of N, O, and S; and n and m are each independently an integer of 1 to 10,000. The block copolymer has excellent mechanical properties along with environmental friendliness and biodegradability.

Claims

1. A block copolymer of Formula 1: ##STR00005## wherein in Formula 1: R.sub.1 and R.sub.2 are each independently hydrogen, N, O, S, or substituted or unsubstituted C.sub.1-20 alkyl; X.sub.1 and X.sub.2 are each independently a direct bond, COO, NRCO, (NR)(COO), RNCONR, or OCOO, wherein the R's are each independently hydrogen or C.sub.1-20 alkyl; L is a direct bond, substituted or unsubstituted C.sub.1-10 alkylene, substituted or unsubstituted C.sub.6-60 arylene, or substituted or unsubstituted C.sub.2-60 heteroarylene containing one or more heteroatoms selected from the group consisting of N, O, and S; and n and m are each independently an integer of 1 to 10,000.

2. The block copolymer of claim 1, wherein X.sub.1, X.sub.2, and L are direct bonds.

3. The block copolymer of claim 1, wherein Formula 1 is the following Formula 1-1: ##STR00006## wherein in Formula 1-1, n and m are the same as defined in claim 1.

4. The block copolymer of claim 1, wherein n is 10 to 700, and m is 10 to 700.

5. The block copolymer of claim 1, wherein a weight average molecular weight of the block copolymer is 10,000 g/mol to 500,000 g/mol.

6. A method of preparing a block copolymer, the method comprising the steps of: preparing a poly(3-hydroxypropionate) (step 1); and preparing the block copolymer by performing a ring-opening polymerization of a glycolide monomer in the presence of a poly(3-hydroxypropionate) initiator (step 2).

7. The method of claim 6, wherein a weight average molecular weight of the poly(3-hydroxypropionate) of the step 1 is 1,000 g/mol to 500,000 g/mol.

8. The method of claim 6, wherein a weight ratio of the poly(3-hydroxypropionate) and the glycolide monomer in the step 2 is 1:99 to 99:1.

9. The method of claim 6, wherein the step 2 is performed in the presence of a catalyst of Formula 4:
MA.sup.1.sub.pA.sup.2.sub.2-p[Formula 4] wherein in Formula 4; M is Al, Mg, Zn, Ca, Sn, Fe, Y, Sm, Lu, Ti, or Zr; p is an integer of 0 to 2; and A.sup.1 and A.sup.2 are each independently an alkoxy or carboxyl group.

10. The method of claim 6, wherein the catalyst is tin(II) 2-ethylhexanoate.

11. A resin, comprising the block copolymer of claim 1.

12. A resin composition comprising the resin of claim 11.

13. The resin composition of claim 12, wherein the resin composition is molded into any one or more molded articles selected from the group consisting of an injection molded article, an extrusion molded article, an inflation molded article, a fiber, a nonwoven fabric, a foam, a film, and a sheet.

14. An article, comprising the block copolymer of claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0051] FIG. 1 shows a graph showing the result of analyzing a block copolymer of Example 1 by NMR.

[0052] FIG. 2 shows a graph showing the result of analyzing a poly(3-hydroxypropionate) of Comparative Example 1 by NMR.

[0053] FIG. 3 shows a graph showing the result of analyzing a polyglycolic acid of Comparative Example 2 by NMR.

[0054] FIG. 4 shows a graph showing the result of measuring the block copolymer of Example 1 by gel chromatography.

[0055] FIG. 5 shows a graph showing the result of measuring a block copolymer of Example 2 by gel chromatography.

[0056] FIG. 6 shows a graph showing the result of measuring biodegradability of the block copolymer of Example 1.

DETAILED DESCRIPTION

[0057] Hereinafter, exemplary embodiments of the present invention will be described in more detail in the following Examples. However, the following Examples are only for illustrating the exemplary embodiments of the present invention, and the content of the present invention is not limited by the following Examples.

Example 1

Preparation Example 1-1: Preparation of poly(3-hydroxypropionate)

[0058] 7 g (77.71 mmol) of 3-hydroxypropionate was dried, and then subjected to a polycondensation reaction in the presence of a p-toluene sulfonic acid (p-TSA) catalyst at 130 C. for 24 hours to prepare poly(3-hydroxypropionate).

[0059] A weight average molecular weight of the prepared poly(3-hydroxypropionate) was 2,430.

Preparation Example 1-2: Preparation of Block Copolymer

[0060] In a 500 mL Teflon-coated round flask, 25 g of glycolide, 5 g of poly(3-hydroxypropionate) prepared in Preparation Example 1-1, and 0.01 g of tin(II) 2-ethylhexanoate were placed. A sufficient vacuum was applied and vacuum drying was performed at room temperature for 4 hours.

[0061] Thereafter, the flask was placed in an oil bath pre-heated to 130 C., and the temperature was raised to 220 C., followed by a ring-opening polymerization reaction for 30 minutes. After the reaction was completed, a final block copolymer was obtained by removing the residual monomer through a devolatilization step of the product.

Example 2

[0062] A block copolymer was prepared in the same manner as in Example 1, except that 15 g of glycolide and 10 g of poly(3-hydroxypropionate) were used instead of 25 g of glycolide and 5 g of poly(3-hydroxypropionate) that was used in Preparation Example 1-2 of Example 1.

Comparative Example 1: Preparation of Poly(3-Hydroxypropionate)

[0063] 7 g (77.71 mmol) of 3-hydroxypropionate was dried, and then subjected to a polycondensation reaction in the presence of a p-toluene sulfonic acid (p-TSA) catalyst at 130 C. for 24 hours to prepare poly(3-hydroxypropionate).

Comparative Example 2: Preparation of Polyglycolic Acid

[0064] In a 500 mL Teflon-coated round flask, 25 g of glycolide, 20 mg of octanol, and 0.01 g of tin(II) 2-ethylhexanoate were placed. A sufficient vacuum was applied and vacuum drying was performed at room temperature for 4 hours.

[0065] Thereafter, the flask was placed in an oil bath pre-heated to 130 C., and the temperature was raised to 220 C., followed by a ring-opening polymerization reaction for 30 minutes. After the reaction was completed, a final homo-copolymer was obtained by removing the residual monomer through a devolatilization step of the product.

[0066] Evaluation

[0067] (1) Nuclear Magnetic Resonance (NMR) Analysis

[0068] NMR analysis was performed at room temperature using an NMR spectrometer including a Varian Unity Inova (500 MHz) spectrometer with a triple resonance 5 mm probe. The block copolymers or polymers of Examples and Comparative Examples were analyzed after being diluted in a solvent at a concentration of about 10 mg/ml, respectively, and chemical shift was expressed in ppm. The solvents used for NMR measurement of Examples and Comparative Examples are as follows.

Example 1: a mixed solvent of CDCl.SUB.3 .and HFIP (hexafluoroisopropanol) at 3:1

Comparative Example 1: CDCl.SUB.3

Comparative Example 2: a mixed solvent of CDCl.SUB.3 .and HFIP (hexafluoroisopropanol) at 3:1

[0069] FIG. 1 shows a graph showing the NMR analysis result of the block copolymer prepared in Example 1, FIG. 2 shows a graph showing the NMR analysis result of poly(3-hydroxypropionate) prepared in Comparative Example 1, and FIG. 3 shows the NMR analysis result of polyglycolic acid prepared in Comparative Example 2.

[0070] Referring to FIGS. 1 to 3, the NMR analysis graph of the block copolymer of Example 1 showed a peak of the 3HP-derived repeating unit and a peak of the glycolide-derived repeating unit.

[0071] (2) Gel Permeation Chromatography (GPC) Analysis

[0072] A weight average molecular weight (Mw) and a number average molecular weight (Mn) of the block copolymers prepared in Examples 1 and 2 were measured using gel permeation chromatography (GPC, Waters' E2640), and the results are shown in FIGS. 4 and 5.

[0073] In detail, the block copolymer prepared in Example 1 was dissolved in hexafluoro isopropanol (HFIP) at a concentration of 2 mg/ml, and 20 l thereof was injected into GPC. HFIP was used as a mobile phase of GPC, and introduced at a flow rate of 1.0 mL/min, and the analysis was performed at 40 C. Two Agilent Mixed-B columns were connected in series. As a detector, an RI detector was used. Mw values were derived using a calibration curve formed using polystyrene standard specimens. 9 kinds of polystyrene standard specimens, each having a weight average molecular weight of 2,000 g/mol, 10,000 g/mol, 30,000 g/mol, 70,000 g/mol, 200,000 g/mol, 700,000 g/mol, 2,000,000 g/mol, 4,000,000 g/mol, or 10,000,000 g/mol, were used.

[0074] (3) Evaluation of Physical Properties

[0075] Tensile strength, Young's Modulus, and tensile elongation of the polymers prepared in Example 1 and Comparative Example 2 were measured.

[0076] In detail, according to ASTM D638, ASTM D536 V type specimen was produced at 190 C. to 200 C. with a hot-press machine (Limotem QM900S), and then measurement was performed using a UTM machine (Universal Testing Machine) at 10 mm/s with a load of 60 kg/f.

TABLE-US-00001 TABLE 1 Tensile Young's Tensile strength modulus elongation (MPa) (MPa) (%) Comparative N/D N/D N/D Example 2 Example 1 32.6 1402 49.27

[0077] According to Table 1, degradation of the polyglycolic acid of Comparative Example 2 occurred during specimen preparation, and it was broken due to the high crystallinity and low elongation, and thus specimen preparation was impossible. Therefore, it was not easy to measure the physical properties through thermal processing.

[0078] In contrast, elongation of the block copolymer of Example 1 was secured, and thus it was possible to measure physical properties through thermoforming and processing, and its physical properties and processability were improved, as compared to the existing polyglycolic acid.

[0079] (4) Measurement of Biodegradability

[0080] The results of measuring biodegradability of a standard material cellulose and the block copolymer of Example 1 under the home composting conditions of EN17427 are shown in FIG. 6.

[0081] In detail, the measurement was performed under home composting conditions (28 C., under aerobic composting conditions, the water content in the compost was set to about 50%, the compost and the test polymer were mixed at a weight ratio of 10:1, and CO.sub.2 generated was measured), and degradation (%) means a value obtained by calculating the weight of the sample decomposed into water and CO.sub.2, based on the initial weight of the sample. In addition, for comparison, the result of measuring biodegradability of the standard material, cellulose (Sigma Aldrich, Cellulose, Cat. No. 310697) is also shown.

[0082] The result of measuring the biodegradability of the block copolymer of Example 1 showed that 40% thereof was decomposed within 40 days, and about 60% of cellulose was decomposed for the same time. It was confirmed that the biodegradability of Example 1 increased over time, as compared to the biodegradability of cellulose. These results confirmed that the block copolymer of Example 1 had the biodegradable property even under relatively mild home composting conditions.