聚丙烯光氧老化研究(Ⅱ)——聚丙烯材料环境适应性行为规律

The Behaviour Rule of Environmental Adaptability on Polypropylene Material

研究了通过稳定剂改性后的聚丙烯材料的熔体状态与在热或光照环境条件下的老化行为规律。研究结果表明,当聚丙烯熔体中仅掺入抗氧剂时,熔体稳定性只说明材料的可加工性,并不能完全代表它的长期耐热效果;当熔体中掺入了光稳定剂和抗氧剂的协同组合体系,不仅熔体状态稳定,且长期耐光老化效果优良,所以聚丙烯从树脂——加工——材料——老化行为是一个整体过程,不仅取决于配合体系的协同效应,还取决于材料加工时的熔体状态。 在聚丙烯光氧老化过程中碳基含量随老化时间增长而增加,所以选取羰基指数来表征聚丙烯材料光氧老化程度准确又可靠。本研究系统跟踪了4组试样在进行人工光(氙灯)加速试验过程中羰基指数变化与试样所接受的紫外辐射累积能量值之间的关联性,得到线性回归方程式:Y=a+bX(Y——羰基指数;X——紫外辐射累积能量值,MI/m^2;a和b为实验常数,随试样类别而异),这4条回归线的相关系数r都在0.9以上,结果令人满意。

Study polypropylene modified with stabilizers on melt state and aging performance under heat-resistance test (140℃) or irradiating test (Xenon Lamp) . The results indicate that melt stability shows materials be capable of processing only while antioxidants are added in alone, does not show absolutely it keeps heat resistance long run test, materials not only show melt stability but also show good irradiation resistance efiiect for long run as UV stabilizers and antioxidants in synergism. As a matter of fact the resin - processing - materails - aging behavior collect as a whole process, depend on both of synergistic formula system and melt state in processing. Carbonyls are increased in company with aging time increased in photooxidation on polypropylene, so it is accurate and reliable to select carbonyl index demonstrating photooxidation level on polypropylene. Based on successive investigation in the reactivity between change of carbonyl index and accumulated UV irradiation energy, selected four group samples proceeding with acceleration test (Xenon Lamp). This paper publish a regression equation Y = a + bX (Y-carbonyl index; X-accumulated UV irradiation energy MJ/m2; a and b are experimental constants, change with different species). The relation coefficient r of four regression lines pass beyond 0.9, be satisfactory.