Cranston Emily, Kawada Jumpei, Raymond Stephane, Morin Frederick G, Marchessault Robert H
Department of Chemistry, McGill University, 3420 University Street, Montreal, Quebec H3A 2A7, Canada.
Biomacromolecules. 2003 Jul-Aug;4(4):995-9. doi: 10.1021/bm034089n.
Synthetic biodegradable poly(butylene adipate-co-butylene terephthalate), P(BA-co-BT), with 56 mol % butylene adipate, BA, was characterized by solid-state NMR spectroscopy, thermal analysis, X-ray diffraction, computer modeling, and polarization microscopy. The NMR study showed the presence of BA and butylene terephthalate, BT. T(1C) NMR measurements proved that some BA and BT units were in crystalline regions. Thermal analysis showed one glass-transition temperature and a single diffuse melting endotherm corresponding to a large melting-point depression of about 100 degrees C compared with poly(butylene terephthalate), PBT. These results suggest that there is only one crystalline phase. An X-ray fiber diagram of a stretched film could be indexed with the same unit cell as that for PBT. Computer modeling showed that the adipate unit fits into the crystal structure of PBT by adopting a TTGTG dihedral angle sequence in the crystalline conformation proposed for the cocrystallization model. The predicted fiber diagram from the proposed model qualitatively agrees with the experimental one. Polarization microscopy revealed that the spherulite growth rate of P(BA-co-BT) was similar to that for poly(butylene adipate), PBA.
合成的可生物降解聚（己二酸丁二醇酯 - 共 - 对苯二甲酸丁二醇酯），即P（BA - co - BT），其中己二酸丁二醇酯（BA）含量为56摩尔％，通过固态核磁共振光谱、热分析、X射线衍射、计算机建模和偏光显微镜进行了表征。核磁共振研究表明存在BA和对苯二甲酸丁二醇酯（BT）。T(1C)核磁共振测量证明一些BA和BT单元存在于结晶区域。热分析显示一个玻璃化转变温度和一个单一的漫散熔融吸热峰，与聚对苯二甲酸丁二醇酯（PBT）相比，熔点大幅降低约100℃。这些结果表明只有一个结晶相。拉伸薄膜的X射线纤维图可以用与PBT相同的晶胞进行索引。计算机建模表明，己二酸酯单元通过在共结晶模型提出的结晶构象中采用TTGTG二面角序列，适合于PBT的晶体结构。从提出的模型预测的纤维图在定性上与实验结果一致。偏光显微镜显示P（BA - co - BT）的球晶生长速率与聚己二酸丁二醇酯（PBA）相似。
