Enhanced crystallization kinetics of poly(lactide) with oxalamide compounds as nucleators: effect of spacer length between the oxalamide moieties
Enhanced crystallization kinetics of poly(lactide) with oxalamide compounds as nucleators: effect of spacer length between the oxalamide moieties
复制标题
DOI：
10.1039/c6ra04050k
复制
发表时间：
2016-05
期刊：
影响因子：
3.9
通讯作者：
Tianfeng Shen;Yunsheng Xu;Xiaoxia Cai;P. Ma;W. Dong;Mingqing Chen
中科院分区：
文献类型：
--
作者：
Tianfeng Shen;Yunsheng Xu;Xiaoxia Cai;P. Ma;W. Dong;Mingqing Chen
聚丙交酯（PLA）的结晶速率较低。为了加快结晶速度，合成了分子式为 C6H5NHCOCONH(CH2)nNHCOCONHC6H5 (n = 2, 4, 6, 8, 12) 的草酰胺化合物作为成核剂 (NA(n))。它们的热性能和成核效率可以通过调整脂肪族间隔基长度（即-(CH2)n-）来定制。 NA(n)的熔化温度和结晶温度随着n值的增加而单调降低，而热分解温度保持恒定。 NA(n)的脂肪族间隔基长度(n)对PLA的结晶动力学影响明显，导致成核效率依次为NA(2) > NA(4) > NA(12) ≈ NA(8) > NA(6)。偏光显微镜结果表明，NA(n)可以自组装成针状超结构，从而促进PLA大分子的结晶。上层结构几何形状和 NA(n) 成核活性的差异导致成核效率的变化。
Poly(lactide), PLA, suffers from low crystallization rate. To speed up the crystallization rate, oxalamide compounds with the formula of C6H5NHCOCONH(CH2)nNHCOCONHC6H5 (n = 2, 4, 6, 8, 12) are synthesized as nucleating agents (NA(n)). Their thermal properties and nucleation efficiency can be tailored by tuning the aliphatic spacer length, i.e., –(CH2)n–. The melting temperatures and crystallization temperatures of the NA(n) decrease monotonically with increasing n value while the thermal decomposition temperature remains constant. The aliphatic spacer length (n) of NA(n) influences obviously the crystallization kinetics of PLA, resulting in nucleation efficiency in the sequence of NA(2) > NA(4) > NA(12) ≈ NA(8) > NA(6). Polarized optical microscopy results show that NA(n) could self-assemble into needle-like superstructures which subsequently promote the crystallization of PLA macromolecules. The differences in superstructural geometry and the nucleation activity of NA(n) are responsible for the variation in the nucleation efficiency.