共聚聚醚酯酰胺的多重转变及其相态结构

The Morphological Structure and Multiphase Transitions of Segmented Polyesteramide

以自行合成的N ,N’ 双 (对甲酯基苯甲酰 )丁二胺 (T4T)为硬段 ,市售平均分子质量为 10 0 0的聚氧丁撑(PTMO10 0 0 )和 1,5 戊二醇 (PDO)的混合体系为软段 ,制备出了PTMO10 0 0 /PDO不同摩尔比的一系列共聚聚醚酯酰胺(T4T PTMO10 0 0 /PDO) .应用H1 NMR分析了单体T4T的化学组成及纯度 ,用差示扫描量热法 (DSC)、动态力学分析(DMA)研究了共聚物的熔融转变及玻璃化转变 ,发现当PDO含量超过 40 %摩尔分数时 ,共聚物显示出两个玻璃化转变和两个熔融转变 ,并且两个玻璃化转变温度均不随组成的改变而变化 ,而熔点则随PDO含量的增加而逐渐提高 .由此认为 ,共聚物中存在两个完全分离的无定形相区和两个具有不同结晶结构的结晶相区 .另外 ,推断有一些PDO链以邻近折叠 (adjacentre entry)

Segmented polyesteramides have been synthesized fr om N,N′-bis(p-carbomethoxybenzoy)butanediamine(T4T) as crystalline segments a nd mixture of poly(tetramethylene oxide) with the average molecular weight 1000 (PTMO 1000 ) and 1,5-pentanediol (PDO) as soft segments. The polymerizati on was carried out in the melt at 250℃ for 1～2 h while vacuum was applied. The chemical composition of the copolymer was measured by H 1-NMR.The melting beh avior of the copolymers was studied by the differential scanning calorimeter. Th e dynamic mechanical properties were investigated on injection moulded bars by m eans of dynamic mechanical analysis. It was found that the copolymers with more than 40% molar ratio PDO showed two glass transition temperatures and two meltin g temperatures. The glass transition temperatures are independent of composition , and thus two fully phase-separated amorphous phases are present. The melting temperatures change with PDO content. The amount of PDO has an effect on both T mA and T mB . T mA is attributed to the lamella consisting of extended T4T segments, while T mB results from the much thicker lam ella consisting of both extended T4T and PDO segments. It is also possible that some PDO is present in the interphase as adjacent re-entry groups. So the resul tant copolymer shows that a complex system, two crystalline phases, two amorphou s phases and an interphase are involved in the copolymer. The under-cooling for these copolymers is small, which means that these segmented copolymers crystall ize fast.