CAJ | 학술논문

合成了末端均为羟基的聚丁二酸丁二醇酯( PBS)预聚物,再以PBS的端羟基引发D-丙交酯( D-LA)开环聚合,得到聚右旋乳酸( PDLA)与PBS的三嵌段共聚物( PDLA-PBS-PDLA).通过凝胶渗透色谱和核磁共振氢谱进行了结构表征.随着m(D-LA)：m(PBS)由0.51：1逐渐增加至2.60：1, PDLA-PDS-PDLA中PDLA链段的长度逐渐增加.随着PDLA嵌段长度的增加, PDLA嵌段对PBS嵌段的限制作用增强,并导致PBS嵌段结晶温度下降,结晶焓降低.当m(D-LA)：m(PBS)=2.60：1时, PBS嵌段不再能形成结晶.而m(D-LA)：m( PBS)在0.51：1~3.04：1范围内, PDLA嵌段均可形成结晶, PDLA嵌段的熔点随其在嵌段共聚物中含量的增加而逐渐升高,但PDLA嵌段的熔融焓呈现先增加后降低的趋势.在部分嵌段共聚物中, PBS和PDLA嵌段可各自形成结晶,且PBS和PDLA的结晶结构不随组分的变化而发生改变,表明该嵌段共聚物中PDLA嵌段和PBS嵌段呈微相分离结构.
합성료말단균위간기적취정이산정이순지( PBS)예취물,재이PBS적단간기인발D-병교지( D-LA)개배취합,득도취우선유산( PDLA)여PBS적삼감단공취물( PDLA-PBS-PDLA).통과응효삼투색보화핵자공진경보진행료결구표정.수착m(D-LA)：m(PBS)유0.51：1축점증가지2.60：1, PDLA-PDS-PDLA중PDLA련단적장도축점증가.수착PDLA감단장도적증가, PDLA감단대PBS감단적한제작용증강,병도치PBS감단결정온도하강,결정함강저.당m(D-LA)：m(PBS)=2.60：1시, PBS감단불재능형성결정.이m(D-LA)：m( PBS)재0.51：1~3.04：1범위내, PDLA감단균가형성결정, PDLA감단적용점수기재감단공취물중함량적증가이축점승고,단PDLA감단적용융함정현선증가후강저적추세.재부분감단공취물중, PBS화PDLA감단가각자형성결정,차PBS화PDLA적결정결구불수조분적변화이발생개변,표명해감단공취물중PDLA감단화PBS감단정미상분리결구.
Poly(D-lactide)-poly(butylene succinate)-poly(D-Lactide)(PDLA-PBS-PDLA) was synthesized by the ring-opening polymerization of D-lactide( D-LA) in the presence of Sn( Oct) 2 and the pre-polymerized PBS as the macro-initiator. The PDLA-PBS-PDLA tir-block polymers were confirmed by gel permeation chromatography( GPC) and nuclear magnetic resonance( 1 H NMR) . Results of differential scanning calorime-ter(DSC) and X-ray diffraction(XRD) revealed that with the increase of Mn of PDLA blocks, the melting temperature and enthalpy of PBS blocks decreased, and the crystallites of PBS blocks could not be detected by DSC when m(D-LA):m(PBS) was set as 2. 60:1. For all the samples, PDLA segment could crystallize. With the increase of the amount of PDLA in the copolymers, the melting temperature of PDLA blocks increased gradually, but the melting enthalpy of PDLA blocks increased first and then decreased. Further-more, both PDLA and PBS blocks could crystallize separately, and the crystal structures PDLA and PBS blocks did not change with m( D-LA):m( PBS) , which revealed that the microphase separation formed in the copolymers.