论文部分内容阅读
研究了树枝状嵌段聚合物聚(ε-b-己内酯)-b-聚苯乙烯(D-PCL-b-PS)的分子结构对PCL链段受限结晶行为的影响.首先,通过活性正离子开环聚合(ROP)合成了树枝状的嵌段聚合物D-PCL.在此基础上用原子转移自由基聚合(ATRP)的方法,合成了树枝状的嵌段聚合物D-PCL-b-PS,在结晶的PCL链段的两个末端引入了不对称的化学键连受限点,对PCL链段在这种条件下的结晶行为进行了研究.当D-PCL-b-PS从熔体中结晶时,在非等温结晶过程中,只有一部分受限程度较轻的PCL链段通过冷结晶的方式形成晶体.而D-PCL-b-PS在等温条件下充分结晶时,不同受限程度的PCL都生长为晶体.当结晶温度较低时(低于30℃时),PCL出现两个熔融峰,分别位于40℃和50℃附近,分别对应于受限程度不同的PCL链段所形成的完善程度不同的晶体;当结晶温度为40℃时,D-PCL-b-PS的两个熔融峰几乎重合.文中最后给出了不同受限程度的PCL链段所对应的构象模型.
The effect of the molecular structure of dendritic block copolymer poly (ε-b-caprolactone) -b-polystyrene (D-PCL-b-PS) on the limited crystallization behavior of PCL segments was studied. Firstly, The dendritic block copolymer D-PCL was synthesized by living cationic ring-opening polymerization (ROP) .At the same time, the dendritic block copolymer D-PCL was synthesized by atom transfer radical polymerization (ATRP) -b-PS, the asymmetric chemical bond limitation point was introduced into the both ends of the PCL segment of crystallization, and the crystallization behavior of PCL segment under this condition was studied.When D-PCL-b-PS When crystallized from melt, only a limited portion of the less-restricted PCL segments form crystals by cold crystallization during non-isothermal crystallization, whereas D-PCL-b-PS is substantially different when isothermally crystallized The PCL at a limited extent grows into crystals.When the crystallization temperature is low (below 30 ° C), PCL shows two melting peaks at around 40 ° C and 50 ° C, respectively, corresponding to PCL chains with different degrees of restriction D-PCL-b-PS, the two melting peaks of D-PCL-b-PS almost coincide with each other when the crystallization temperature is 40 ℃ .There are different degrees of PCL Conformational model corresponding to the segment.