中文摘要：

合成了系列聚右旋乳酸（PDLA）嵌段重量分率（fw=0～0.61）的窄分子量分布聚苯乙烯-b-聚右旋乳酸二嵌段共聚物（PS-b-PDLA）.运用温度调制示差扫描热分析仪（TMDSC）和热台偏振光显微镜（POM）等研究手段,对制备所得的结晶性二嵌段共聚物的热性能、结晶速率与结晶形貌等进行了研究.研究结果表明,与聚右旋乳酸均聚物相比,随着PS-b-PDLA中结晶性PDLA嵌段重量分率fw减少,无定形聚苯乙烯嵌段（PS）对PDLA嵌段链段的结晶抑制作用增强,PS-b-PDLA的热结晶性能与结晶形貌发生显著变化;相对于PDLA均聚物,PS-b-PDLA的冷结晶温度（Tcc）和结晶平衡熔点（Tm0）分别下降14℃和38℃,球晶生长速率明显降低.在无定形PS嵌段链段的玻璃化温度（Tg）附近,二嵌段PS-b-PDLA的结晶行为出现拐点,揭示PS嵌段由于相分离所形成纳米微相空间对PS-b-PDLA中PDLA链段的结晶产生影响,并且该影响作用程度与PDLA嵌段的重量分率fw和结晶温度（Tc）相关。

英文摘要：

A new series of diblock polystyrene-b-poly（D-lactide）（PS-b-PDLA） were successfully synthesized with narrow molecular weight distribution and a PDLA block weight fraction fw of 0 ～ 0.61.By means of temperature-modulated differential scanning calorimeter（TMDSC）,DSC and polarized optical microscopy,thermal and crystallization kinetics of these diblock copolymers have been studied along with the semicrystalline PDLA homopolymer.It was found that the increase in rigid amorphous polystyrene block led to remarked confinement effect on melting point,degree of crystallinity and crystallization kinetics for the semicrystalline PDLA blocks.The cold crystallization temperature and crystal equilibrium melting temperature for the PDLA block chains were revealed to be 14℃ and 38℃ lower than those of PDLA homopolymers,respectively.It was also noted that the crystallization behavior and apparent crystal growth rate were observed to vary at a temperature near the glass transition temperature of PS block chains.In addition,POM results indicated the diblock PS-b-PDLA organized spherulites,and apparent crystal growth rates not only depended on isothermal crystallization temperature,but the PDLA blocks weight fraction.Taking the effect of crystallization of PDLA blocks into consideration,these evidences may be helpful for controlled fabrication of 3D mesoscopic structures by self-assembling diblock PS-b-PDLA.