聚丙烯改性研究

太原理工大学

硕士学位论文

聚丙烯改性研究

姓名：王文杰

申请学位级别：硕士专业：高分子化学与物理指导教师：吕志平

20100501

聚丙烯改性研究

摘要

本文利用对叔丁基苯甲酸、钛酸四异丙酯和正硅酸乙酯合成了钛类新型成核剂，考察了此类成核剂的性能；并探讨研究了N-甘氨酸基马来酰胺酸（GMA）、N-甘氨酸基马来酰胺酸钙（GMACa）和N-二乙酸基马来酰亚胺（DAMI）熔融接枝到聚丙烯上的可行性，考察了改性后聚丙烯的性能。

通过热重分析（TG）、X-射线衍射分析（XRD）、差示扫描量热分析（DSC）、偏光显微镜和力学性能测试等手段进行了表征，并测试了聚丙烯的维卡软化点和熔融指数。

TG测试结果表明：

钛类成核剂在温度为254.1℃时开始分解，这说明此类成核剂在聚丙烯加工温度（200-220℃）下是稳定的，可以作为聚丙烯的成核剂。

DSC、XRD、维卡软化点和偏光显微镜测试结果表明：

钛类成核剂为有效的聚丙烯α晶型成核剂，在聚丙烯中加入0.3%的成核剂TST后，其结晶温度和结晶速率都有了不同程度的提高，分别比纯PP提高了15.62℃和3%，结晶起始温度与结晶峰温度之差也由纯PP的4.4℃降低到了2.8℃；聚丙烯的维卡软化点比纯PP提高了7.7℃；聚丙烯的球晶尺寸明显减小，晶粒之间的界面模糊。

熔融接枝改性聚丙烯后，聚丙烯的结晶速率、结晶度和维卡软化点均有不同程度的提高，其中GMA在其质量分数为2%时，聚丙烯的结晶温度和

结晶度分别比交联基础数据提高了9.18℃和5.6%；聚丙烯的维卡软化点提高了18.1℃；聚丙烯的晶粒明显细化，球晶之间界限不明显。

力学性能测试结果表明：

利用钛类成核剂改性后，聚丙烯的力学性能都有了不同程度的提高。其中拉伸强度最大为40.54MPa，最大增幅为15.2%；抗弯曲强度最大为61.35MPa，最大增幅为26.3%；抗冲击强度最大为13.02kJ/m2，最大增幅为114.9%。

利用熔融接枝改性聚丙烯后，聚丙烯的拉伸强度、抗弯曲强度和抗冲击强度比交联基础数据也有了大幅度地提高，而且尤以接枝N-甘氨酸基马来酰胺酸后聚丙烯的力学性能最好，其拉伸强度、抗弯曲强度和抗冲击强度最大分别为41.18MPa、51.74MPa和17.35kJ/m2。

关键词：聚丙烯，成核剂，钛类成核剂，熔融接枝，性能

STUDY ON MODIFICATION OF POLYPROPYLENE

ABSTRACT

In this paper, a kind of new titanium nucleating agents were prepared by isopropyl titanate, p-tert-butyl-benzoic acid and tetraethyl orthosilioate, and their performance were investigated. The feasibility of melt-grafteded polypropylene(PP) by maleic anhydride(MAH), N-glycine amide maleic acid (GMA), N-glycine amide maleic calcium (GMACa) and N-diacetic acid maleimide (DAMI) were explored, and the performance of modified polypropylene were also studied.

The modified polypropylene with new nucleating agents were tested by the methods of thermogravimetric analysis (TG), X-ray diffraction analysis(XRD), differential scanning calorimetry(DSC), polarizing microscopy and biomechanical testing, and vicat softening point and melt index were also tested.

The results of TG show that titanium nucleating agent begin to decompose at the temperature of 254.1℃. They are stable in the polypropylene’s processing

℃, so they can be used as nucleating agent of temperature (200-220)

polypropylene.

The results of DSC, XRD, vicat softening point and polarizing microscopy show that the titanium nucleating agent are effective α crystalline nucleating agent of polypropylene, the crystallinity, crystallization temperature and crystallization rate of modified polypropylene have been increased in varying

degrees. Compared with pure PP, the crystallization temperature and crystallinity are increased 15.62℃ and 3%, the difference of crystallization onset temperature and crystallization peak temperature reduced from 4.4℃ of the pure PP to 2.8℃, vicat softening point of modified polypropylene increased 7.7℃. Polypropylene’s spherulite size are decreased significantly, and the boundaries between grains are weakened.

The crystallization rate and crystallinity of modified PP by melt grafting have been improved to some extent, Compared with the cross-linking blank in 2% of GMA’s mass fraction, polypropylene’s crystallization temperature and crystallinity are increased 9.18℃ and 5.6%; vicat softening point of modified polypropylene increased 18.1℃, the grains of modified polypropylene are refined significantly, and the boundaries between spherulites are not obvious.

The mechanical properties of PP modified with titanium nucleating agents are improved in varying degrees, the maximum of tensile strength is 40.54MPa, and the largest increase is 15.2%; the maximum of anti-bending is 61.35MPa, and the largest increase is 26.3%; the maximum of impact strength is 13.02kJ/m2, and the largest increase is 114.9%.

The melt grafted polypropylene’s tensile strength, flexural strength and impact strength have been significantly increased compared with cross-linked blank of PP. The mechanical properties of grafted polypropylene by N-glycine Maleic acid amide are the best, their largest tensile strength, flexural strength and impact strength are 41.18MPa, 51.74MPa and 17.35kJ/m2.