改性程度和质量比对QMS/PVA复合膜增韧作用的影响

Influences of modification level and mass ratio on toughening effect for QMS/PVA composite films

为提高淀粉/聚乙烯醇(PVA)复合膜在纺织上浆等以薄膜为基础的应用领域中的使用效果,通过两步法合成了季铵盐醚化-顺丁烯二酸酯化淀粉(QMS),以QMS/PVA复合膜的断裂强度、断裂伸长率和耐挠曲疲劳性为量化指标,探索了QMS的改性程度(季铵盐醚化和顺丁烯二酸酯化改性程度之和)对QMS/PVA复合膜的增韧规律,考察了PVA与QMS的质量比对这种复合膜韧性的影响。研究发现:QMS/PVA复合膜的断裂强度由改性前的21.6 MPa逐渐降低到QMS改性程度为0.061的14.8 MPa,断裂伸长率和耐挠曲次数分别由26.6%和4 348次逐渐提高到29.5%和5 388次;QMS/PVA复合膜的断裂伸长率和耐挠曲次数由PVA与QMS的质量比为0的3.35%和2 128次逐渐增加到质量比为100%的43.9%和7 889次,而断裂强度由27.1 MPa逐渐下降为12.1 MPa。由此表明PVA与QMS的质量比是QMS/PVA复合膜韧性的主要影响因素,综合各指标PVA与QMS的质量比约为66.7%时为宜。

In order to improve the usability of starch/polyvinyl alcohol（PVA）composite film in the application based on the films such as warp sizing in textile,the preparation of quaternized-maleated cornstarch（QMS）was performed by a method of two-step reaction.In terms of the tensile strength,the breaking elongation,the flex fatigue resistance,and the toughening law of modification level（the sum of quaternization level and maleation one）on QMS/PVA composite films was explored,and the effect of mass ratio of PVA to QMS on the toughness of QMS/PVA composite films was also investigated.It can be found that the tensile strength of QMS/PVA composite films reduces from 21.6 MPa to 14.8 MPa,and the breaking elongation and the number of bending of QMS/PVA composite film increase from 26.6%to 29.5% and from 4 348 cycles to 5 388 cycles when the modification level of QMS is 0.061.When the mass ratios of PVA to QMS changes from 0to 100%,the elongation of QMS/PVA composite films rises from 3.35%to 43.9%,the number of bending increases from 2 128 cycles to 7889 cycles,and the strength decreases from 27.1MPa to 12.1MPa.These results suggest that the mass ratio is the index of actors that influences the toughness of QMS/PVA composite films.The suitable mass ratio is about 66.7% based on the film properties.