Biodegradable poly(butylene succinate) and its copolyesters with minor amounts of propylene succinate/montmorillonite nanocomposites

• Main Authors: Chen-zhe Wu, 吳臣哲
• Other Authors: Ming Chen
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/fthz49

碩士 === 國立中山大學 === 材料與光電科學學系研究所 === 103 === In this study, biodegradable nanocomposites were prepared. In order to improve the compatibility between polymer and montmorillonite (MMT), the surface of MMT was organo-modified by disodium cocoamphdipropionate (K2). Then, poly(butylene succinate) (PBSu) and its copolyesters with minor amount of propylene succinate (PBPSu90/10, PBPSu80/20) were blended with 1, 3, or 5 wt% of MMT-K2, respectively, by the melt intercalation. The physical properties of these biodegradable nanocomposites were characterized before studying their crystallization and melting behaviors. The Fourier Transform Infrared spectrum and wide-angle X-ray diffraction (WAXD) pattern show that MMT was successfully modified with K2, and the interlayer distance of MMT was increased from 1.62 to 3.94 nm. The WAXD patterns of nanocomposites yield that the interlayer distance of MMT-K2 was higher than 5.94 nm. The micrographs of transmission electron microscope indicate that these nanocomposites were intercalated, not exfoliated. The results of thermogravimetric analysis revealed that the thermal stability of the resultant nanocomposites was reduced after the addition of MMT-K2. Dynamic mechanical properties of the fabricated 3wt% or 5 wt% nanocomposites of these aliphatic copolyesters showed significant enhancements in the storage modulus compared with the neat matrix, even higher than that of PBSu. The effect of MMT-K2 on the isothermal crystallization behavior of PBSu, PBPSu90/10, and PBPSu80/20 was investigated using a differential scanning calori- meter (DSC) and polarized light microscopy (PLM). The Avrami equation successfully describes the isothermal crystallization kinetics of these nanocomposites and the value of Avrami exponent was between 2.42 and 3.35. The crystallization rate of neat BP80 was faster than BP80/MMT nanocomposites. This may be ascribed to the incompatibility of BP80 with MMT. On the contrast, the crystallization rate of BP90 or B100 nanocomposites was enhanced as the amount of MMT-K2 increased. The molecular weight of neat polymer before and after the melt intercalation indicated that the reduced molecular weight resulted in the increase of the growth rate of spherulites. Besides, it was found that the incorporation of MMT-K2 has little effect on the crystalline structure as well as the melting behavior of B100, BP90, or BP80.