Impact of particle morphology on structure, crystallization kinetics, and properties of PCL composites with TiO2-based particles
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- 作者：Taťana Vacková ; Jaroslav Kratochvíl ; Aleksandra Ostafinska…
- 刊名：Polymer Bulletin
- 出版年：2017
- 出版时间：February 2017
- 年：2017
- 卷：74
- 期：2
- 页码：445-464
- 全文大小：
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Polymer Sciences; Soft and Granular Matter, Complex Fluids and Microfluidics; Characterization and Evaluation of Materials; Physical Chemistry;
- 出版者：Springer Berlin Heidelberg
- ISSN：1436-2449
- 卷排序：74
文摘
Crystallization kinetics of polycaprolactone (PCL) filled with TiO2-based particles (TiX) was shown to depend on the TiX particle type and concentration, which were associated with a slight polymer matrix degradation. The partially degraded, shorter, and more mobile polymer chains increased the overall crystallization rate at the initial stage of crystallization, while at the later stages, the non-nucleating TiX particles acted as a sterical hindrance, slowing down the crystallization process. The PCL/TiX composites were prepared by melt-mixing and contained 2.5 and 5 wt% of the filler. The investigated TiX particles included isometric anatase microparticles (mTiO2) and titanate nanotubes with high-aspect ratio (TiNT). Light and electron microscopy showed very homogeneous dispersion of the mTiO2 particles in the PCL matrix, while the TiNT formed large agglomerates. In situ polarized light microscopy displayed faster isothermal crystallization of all PCL/TiX composites, but the micrographs indicated that the TiX particles did not act as nucleation centres. Isothermal DSC experiments, evaluated in terms of Avrami theory, confirmed the PLM results and showed that the overall rate of isothermal crystallization increased in the following order: PCL <PCL/TiNT <PCL/mTiO2. Non-isothermal DSC and rheological measurements revealed the correlation between the crystallization rate and the polymer matrix degradation—the well-dispersed mTiO2 particles with high specific surface caused the highest PCL degradation and, consequently, the earliest start of non-isothermal crystallization as well as the fastest isothermal crystallization. Microindentation hardness measurements confirmed that the partial degradation of the polymer matrix did not have a significant impact on the mechanical performance of PCL/mTiO2 composites.