Aliphatic polycarbonate with long-chain branches and aromatic copolyester thereof

Abstract

Provided is an aliphatic polycarbonate-co-aromatic polyester with long-chain branches. The copolymer includes repeating units represented by OAO and Z(O).sub.a, which are linked via carbonyl (C(O)) and C(O)YC(O) as linkers. Also provided is an aliphatic copolycarbonate including repeating units represented by OAO and Z(O).sub.a, which are linked via carbonyl (C(O)) linkers. The aliphatic copolycarbonate has a weight average molecular weight of 30,000 or more.

Claims

1. An aliphatic polycarbonate comprising repeating units represented by OAO and Z(O).sub.a linked via carbonyl (C(O)) linkers and having a weight average molecular weight of 30,000 or more wherein A is selected from substituted or unsubstituted C.sub.3-C.sub.60 alkylene groups and combinations thereof, a is an integer equal to or greater than 3, and Z is an a-valent substituted or unsubstituted C.sub.4-C.sub.60 radical, and wherein HOAOH as a raw material of the repeating units OAO is selected from the group consisting of the compounds of Formulae 1a to 1h: ##STR00004## and Z(OH).sub.a as a raw material of the repeating units Z(O).sub.a is selected from the group consisting of the compounds of Formulae 2a or 2c: ##STR00005##

2. The aliphatic polycarbonate according to claim 1, wherein HOAOH as a raw material of the repeating units OAO is the compound of Formula 1a: ##STR00006##

3. The aliphatic polycarbonate according to claim 2, wherein the amount of the Z(O).sub.a is from 0.1 to 0.4 mol %, based on the moles of the repeating units OAO.

4. The aliphatic polycarbonate according to claim 1, wherein the linkers further comprise C(O)YC(O) and Y is selected from substituted or unsubstituted C.sub.5-C.sub.20 arylenes, substituted or unsubstituted C.sub.5-C.sub.20 heteroarylenes, and combinations thereof.

5. The aliphatic polycarbonate according to claim 1, wherein the aliphatic polycarbonate is prepared in the presence of a base catalyst, and wherein the base catalyst consists of a lithium, sodium, or potassium cation and an alkoxy anion formed by deprotonation of the HOAOH.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows conventional strategies for the preparation of aliphatic polycarbonates.

MODE FOR CARRYING OUT THE INVENTION

(2) The effects of the present invention will be explained in detail with reference to the following examples, including comparative examples. However, these examples are provided for illustrative purposes only and are not intended to limit the scope of the invention.

Examples 1-11

Preparation of Aliphatic Polycarbonate-co-aromatic Polyesters Having Long-chain Branches (Condensation Reactions of the Compound of Formulae 1a and the Compounds of 2a to 2d with DMC and Dimethyl Terephthalate)

(3) Step 1: 1,4-butanediol (Formula 1a, 10.0 g, 110 mmol) and each of the compounds of Formulae 2a to 2d were placed in a three-neck flask and NaOH (0.222 mmol, 0.2 mol %) was added thereto. The compounds of Formulae 2a to 2d were used in amounts of 0.2-0.7 mol %, as shown in Table 1. After further addition of toluene (10 ml), a mechanical stirrer was connected to one neck of the flask, a manifold attached with a vacuum line and a nitrogen line was connected to another neck of the flask, and a Dean-Stark trap was connected to the remaining neck of the flask. After the reaction flask was immersed in a thermostatic bath, water was removed from the mixture by azeotropic distillation with the toluene under reflux. After 2 h, the mixture was allowed to cool to room temperature and remaining toluene was then removed under vacuum. The Dean-Stark trap was removed, and instead, a distillation unit was connected to the flask. 9.30 g (103 mmol) of dimethyl carbonate (DMC) and 8.62 g (44 mmol) of dimethyl terephthalate derived from terephthalic acid were added. After the reaction flask was immersed in a thermostatic bath at 120 C., the reaction was carried out for 1 h while distilling off formed methanol and a portion of the DMC at ambient pressure. After heating to 190 C., the reaction was continued while removing volatiles under a reduced pressure of 570 mmHg for 0.5 h, under a reduced pressure 380 mmHg for 1 h, and under a reduced pressure 190 mmHg for 2 h. Thereafter, the reaction was continued at 210 C. for additional 2 h while removing volatiles under a high vacuum of 0.3 mmHg, which was maintained using a vacuum pump. The experimental results are summarized in Table 1.

(4) TABLE-US-00001 TABLE 1 <Preparation of aliphatic polycarbonate-co-aromatic polyesters having long-chain branches> Z(OH).sub.a/amount Gel proportion.sup.d (mol %) based on BD Yield.sup.a (%) M.sub.w.sup.b M.sub.w/M.sub.n.sup.b T.sub.m.sup.c ( C.) (%) Example 1 Formula 2a/0.25 91 118000 2.34 38-140 (48, 112) Example 2 Formula 2a/0.40 91 201000 3.72 39-140 (49, 112) Example 3 Formula 2a/0.50 91 190000 4.30 39-137 (48, 111) Example 4 Formula 2a/0.60 92 209000 5.51 39-138 33 (53, 113) Example 5 Formula 2a/0.70 91 123000 3.61 35-141 54 (50, 114) Example 6 Formula 2b/0.20 90 140000 3.00 40-140 (48, 112) Example 7 Formula 2c/0.20 92 116000 2.44 38-140 (48, 114) Example 8 Formula 2d/0.20 90 174000 3.45 43-142 (53, 114) Example 9 Formula 2d/0.30 91 213000 5.03 47-138 23 (55, 110) Example 10 Formula 2d/0.40 93 216000 5.21 31-137 17 (41, 114) Example 11 Formula 2d/0.50 90 129000 3.89 41-139 62 (48, 112) .sup.aValue calculated from the mass of the obtained polymer relative to the mass of 1,4-butanediol added. .sup.bValue measured on the basis of polystyrene standard in THF at 40 C. by GPC. .sup.cMelting point measured by DSC, .sup.dProportion of the mass of gel in the mass of the obtained polymer.

Comparative Example 1

Preparation of Aliphatic Polycarbonate-co-aromatic Polyester without Using Z(OH)a

(5) The procedure of Examples 1-11 was repeated except that none of the Z(OH).sub.a compounds (Formulae 2a to 2d) were added. Yield=90%, M.sub.w=108000, M.sub.w/M.sub.n=1.69, T.sub.m=121 C.

Examples 12-20

Preparation of Aliphatic Polycarbonates Having Long-chain Branches (Condensation Reactions of the Compound of Formula 1a, the Compounds of Formulae 2a to 2d with DMC)

(6) Step 1: The procedure of Examples 1-11 was repeated until water was removed from the mixture. Thereafter, the addition of dimethyl terephthalate was omitted, and instead, the amount of DMC was increased to 15.7 g (174 mmol). After the reaction flask was immersed in a thermostatic bath at 120 C., the reaction was carried out for 1 h while distilling off formed methanol and a portion of the DMC at ambient pressure. After heating to 190 C., the reaction was continued while removing volatiles under a reduced pressure of 570 mmHg for 0.5 h, under a reduced pressure 380 mmHg for 1 h, and under a reduced pressure 190 mmHg for 2 h. Thereafter, the reaction was continued for additional 2 h while removing volatiles under a high vacuum of 0.3 mmHg, which was maintained using a vacuum pump. The experimental results are summarized in Table 2.

(7) TABLE-US-00002 TABLE 2 <Preparation of aliphatic polycarbonates having long-chain branches> Z(OH).sub.2/amount Gel proportion.sup.d (mol %) based on BD Yield.sup.a (%) M.sub.w.sup.b M.sub.w/M.sub.n.sup.b T.sub.m.sup.c ( C.) (%) Example 12 Formula 2a/0.20 85 243000 3.62 41-61 (54) Example 13 Formula 2a/0.30 90 203000 3.67 41-63 (57) Example 14 Formula 2a/0.40 90 263000 4.70 41-61 3.8 (55) Example 15 Formula 2a/0.50 92 246000 4.87 41-61 17 (55) Example 16 Formula 2a/0.60 89 235000 4.68 40-60 47 (55) Example 17 Formula 2d/0.20 91 218000 4.13 41-62 (56) Example 18 Formula 2d/0.30 88 249000 4.60 40-60 67 (55) Example 19 Formula 2d/0.40 88 183000 4.03 41-62 36 (57) Example 20 Formula 2d/0.50 86 161000 4.91 42-62 38 (57) .sup.aValue calculated from the mass of the obtained polymer relative to the mass of 1,4-butanediol added. .sup.bValue measured on the basis of polystyrene standard in THF at 40 C. by GPC. .sup.cMelting point measured by DSC, .sup.dProportion of the mass of gel in the mass of the obtained polymer.

Comparative Example 2

Preparation of Aliphatic Polycarbonate without Using Z(OH)a

(8) The procedure of Examples 12-20 was repeated except that none of the Z(OH).sub.a compounds (Formulae 2a to 2d) were added. Yield=90%, M.sub.w=146000, M.sub.w/M.sub.n=1.53.

(9) From the above results, the aliphatic polycarbonates and their aromatic copolyesters prepared by further condensation with the polyol compounds in Examples 1-20 had long-chain branches, high molecular weights, and broad molecular weight distributions compared to the polymers prepared in Comparative Examples 1 and 2.