催化剂对L-乳酸和乙醇酸共聚物结构性能的影响

以L-乳酸(LA)和乙醇酸(GA)(LA:GA摩尔比为20:80)为原料,在170℃、压力小于70 Pa下反应10 h,直接熔融聚合合成乳酸-乙醇酸共聚物(PLGA),研究了催化剂种类、催化剂用量以及复配催化剂比例对PLGA特性粘数的影响。结果表明,使用复合催化剂氯化亚锡(SnC l2)与对甲基苯磺酸(TSA),摩尔比为1:1,其中SnC l2相对LA与GA的总质量的质量分数为0.4%时,所得PLGA产物的特性粘数较高,为0.352 dL/g。红外光谱和核磁共振氢谱表明,PLGA为LA与GA共聚物,共聚产物中GA比例大于投料值,由差示扫描量热分析和X射线衍射分析表明,PLGA为非结晶高聚物。

Effect of catalyst on structure and property of poly(lactic acid-glycolic acid)

Poly(lactic acid-glycolic acid)(PLGA) was synthesized from L-lactic acid(LA) and glycolic acid(GA) at the mole ratio of 2080 via direct melt polycondensation for 10 h at 170℃ and system pressure below 70 Pa.The effects of catalyst variety and amount and the compound proportion of compound catalyst on the intrinsic viscosity of PLGA were studied.The results showed that the obtained PLGA had a relatively high intrinsic viscosity of 0.352 dL/g when the compound catalyst of stannous chloride(SnCl2) and p-toluene sulfonic acid(TSA) was used at the mole ratio of 11 and the mass fraction of SnCl2 was 0.4% to the total mass of LA and GA.The IR and NMR spectra showed that PLGA was the copolymer product of LA and GA with the GA proportion higher than the feeding ratio.The DSC and X-ray diffraction spectra showed that PLGA was an amorphous polymer.