Nucleation Effect of Thermotropic Liquid Crystalline Polymer on the Crystallization of Polycaprolactone. Polymers & Polymer Composites, 2010, 18(1), to appear.
writer：Defeng Wu, Yisheng Zhang, Minge Gao, Ming Zhang.
keywords：polycaprolactone; thermotropic liquid crystalline polymer; blend; nucleation; crystallization.
source：期刊
specific source：Polymers & Polymer Composites
Issue time：2010年
Polymers & Polymer Composites, 2010, 18(2), 91-101.
ABSTRACT:
Polycaprolactone (PCL) has attracted much attention in recent years due to its good biodegradability and biocompatibility. As a semicrystalline polymer, the final properties of PCL materials highly depend on the bulk crystallization level. However, PCL shows lower crystallization temperature and rate than other aliphatic polyesters, which restricts its further applications. To improve the crystallization is hence the key problem to control the performance of PCL materials. In this work, a thermotropic liquid crystalline polymer (TLCP) was used as the nucleating agent to improve the crystallization of PCL. The PCL/TLCP blend with the maximum TLCP content of 10 wt% was prepared by melt mixing. The nonisothermal crystallization behaviour of the PCL matrix was studied using differential scanning calorimetry (DSC) and polarized optical microscope (POM), and the crystallization kinetics was then further analyzed by several methods such as Avrami, Ozawa, Mo, Ziabicki, Lauritzen-Hoffman and Kissinger models. The results show that the presence of the solid TLCP particles could enhance crystallization temperature of the PCL matrix evidently at very small content levels (1 wt%). Although the mobility of PCL chain segments decreases with increasing TLCP content, the heterogeneous nucleation effect of TLCP particles is always the dominant role on the overall crystallization. Therefore, the blend systems present higher crystallization rate and ability than those of the neat PCL. The kinetics analysis and the data obtained in this work could be useful to optimize the processing conditions and to improve the crystallization of the PCL materials.
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