半胱氨酸改性聚丙烯膜的热稳定性与力学性能

 通过热力学分析、热重分析、力学分析研究半胱氨酸改性聚丙烯膜的力学性能及热稳定性,考察半胱氨酸改性聚丙烯膜的实用性。研究表明:紫外光在N2气氛中对聚丙烯中空纤维膜力学性能无明显影响,但空气中紫外光照可造成PP膜断裂强力的下降;经过半胱氨酸改性后,改性膜的断裂伸长率随接枝率的增加而降低,且玻璃化转变温度也随之降低,即大分子柔性增加;改性膜表面的半胱氨酸接枝侧链热稳定性较差,在N2、O2中的最高使用温度分别是212.4、191.5℃。

Thermal stability and mechanical property of hollow fiber polypropylene membrane modified by cysteine

To evaluate the practicability of hollow fiber polypropylene membrane modified by cysteine(PP-g-Cys),its thermal stability and mechanical properties were analyzed by dynamic mechanical thermal analysis,thermogravimetry and tensile test.The results show ultraviolet irradiation has little effect on the mechanical property of polypropylene hollow fiber membrane in N2,whereas it decreases the break strength of the membrane in atmosphere.The elongation at break of PP-g-Cys descends with the increase of grafting degree.And the glass transition temperature(Tg) of PP-g-Cys drops,that is,the macromolecule becomes softer.The cysteine grafted side chain on PP-g-Cys membrane is thermally unstable,the its highest application temperature of the modified membrane is 212.4℃and 191.5℃in N2and O2respectively.