材料科学
极限抗拉强度
热稳定性
结晶度
差示扫描量热法
傅里叶变换红外光谱
化学工程
高分子化学
聚合物
复合材料
物理
工程类
热力学
作者
Qiujin Li,Wei Qi,Rongxin Su,Zhimin He
标识
DOI:10.1163/156856209x412173
摘要
Enzyme-modified konjac glucomannan (KGM) and xanthan blend films have been prepared and characterized. Enzymatic hydrolysis of purified KGM by β-mannanase yielded samples of various weight-average molecular weight (M w) that were determined by size-exclusion chromatography coupled with multi-angle laser light scattering (SEC-MALLS) and calculated using the established Mark–Houwink–Sakurada equation [η] = 4.07 × 10−4 M w 0.733. KGM degradation products were blended with xanthan for preparation of films that were used in orthogonal-designed experiments. These films were characterized in terms of their structures, thermal stability, crystallinities and mechanical properties. The results of Fourier transform infrared spectroscopy indicated that, after blending, there was strong intermolecular interaction caused by hydrogen bonds between xanthan and KGM hydrolysates. This phenomenon was more marked at lower M w of KGM. The thermal stability of the blend films determined by differential scanning calorimetry was higher with increasing KGM molecular weight. The degrees of crystallinity characterized by X-ray diffraction (XRD) decreased with the increasing content of non-degraded KGM. Mechanical properties of the polymer blends including the tensile strength and elongation rate were also correlated to M w of KGM. The tensile strength achieved a maximum at 10.25 MPa with KGM of M w = 4.25 × 105 and the elongation rate reached a maximum value of 89.5% with KGM of M w = 8.95 × 105. These results were directly attributed to intermolecular interactions between xanthan and KGM, and this synergistic behavior led to good physicochemical and mechanical performance of the blended films.
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