【作者】 孙晓东；

【导师】 苑会林；

【作者基本信息】 北京化工大学 ， 材料科学与工程， 2016， 硕士

【摘要】 聚烯烃通过熔融接枝,可有效提高与其他高分子材料的相容性,扩大其使用范围。本文采用熔融接枝法制备出聚烯烃类相容剂,将接枝产物引入极性/非极性合金体系,对其增容作用和机理进行了研究。并制备了复合基体型相容剂,研究了其性能。首先,以PP、PE等常用聚烯烃材料为基体,在引发剂DCP和接枝单体MAH或GMA的作用下,通过熔融接枝方法制备了一系列接枝产物。结合多种形态表征手段,研究接枝单体、共单体、引发剂、反应温度、螺杆类型、转速等对相容剂接枝率,熔体流动速率的影响。结果发现：在红外光谱中证实了GMA接枝反应的发生。苯乙烯作为第二单体,能够有效地改善接枝情况。接枝率随接枝单体、引发剂的增加先增大后减小。在MAH2.0份、GMA4.0份、DCP0.08份时,接枝率达到最大。此外,苯乙烯的加入能进一步的提高接枝率,抑制副反应的发生。当苯乙烯与接枝单体用量为1：1时,接枝效果最佳。HDPE接枝后,材料的熔点下降,结晶温度升高。PP接枝后,接枝支链促进异相成核,使晶粒细化。然后,将相容剂加入PP/PA6的非极性／极性合金体系中,考察接枝物对合金体系力学性能的影响,并观察共混物的微观形貌。研究发现：加入6.0份MAH接枝物或6.0份GMA接枝物,且固定PA6含量为20份时,合金的力学性能最佳。PP-g-MAH和PP-g-GMA都能作为PP/PA6合金的有效增容剂,改善界面粘结情况。且用PP-g-MAH和PP-g-GMA两种接枝物复合作为相容剂加入到共混物中比单独使用一种的效果好。最后,将PP和EVA同时与MAH和GMA接枝,制备复合基体型相容剂,研究不同比例的PP/EVA接枝物对接枝率,熔体流动速率等影响。发现PP/EVA的比例为50/50时,体系的性能最佳,但由于副反应增多,接枝率下降。而熔融指数是随着体系中EVA组分的增多而增大。接枝后体系的熔点和结晶温度都有上升。拉伸和弯曲强度也有提升。扫描电镜图片显示,接枝后PP和EVA相容性得到改善,大粒径颗粒明显变少。体系中加入GMA接枝的效果比MAH好,这与单一基体接枝情况相同。更多还原

【Abstract】 The compatibility of polyefins can be effectively enchanced with other polymer materials by melt grafting method, thus broadening the application of polyolefins.In this research, polyolefin-based compatilizers prepared by melt grafting to introduce into the polar/non-polar blend systems to validate the effectiveness of compatibilization and the mechanisms of compatibilization systematically investigated.Also, Compound matrix compatilizers were prepared and performances were researched.Firstly, a series of graft products were prepared by melt grafting method which had employed general polyolefins such as PP and PE were used as the matrix, DCP as the initiator and MAH or GMA as the monomers. The influences of graft monomer, co-monomer, initiator, reaction temperature and screw type on the grafting rate and the products’ melt flow rate were respectively investigated the occurrence of GMA grafting reaction and showed that styrene, could improve graft as the second monomer. With the rise of loading of the graft monomer and the initiator, grafting yield first increased and then decreased. When the laoding of MAH, GMA and DCP were respectively 2.0 phr,4.0 phr and 0.08 phr, grafting yield met a peak. It was also found that the addition of styrene could furtherly improve the grafting yield and inhibit the side reactions. The best grafting effect was achieved when the loading ratio of the graft monomer and styrene was 1:1. The grafted product of HDPE met a drop of the melting point but a rise of the crystallization temperature, where as the graft of PP favored the heterogeneous nucleation and grain refinement.Subsequently, the compatilizer was introduced into PP/PA6 non-polar/polar blend system to investigate its effect on the mechanical properties by analyzing the morphology of the blend. It was found that when the content of PA6 was 20 phr, both PP-g-MAH and PP-g-GMA provided the maximum improvement in mechanical properties when the loading amount was 6.0 phr, which inferred that either PP-g-MAH or PP-g-GMA could be used as effective compatilizer because it could improve the interface bonding of PP/PA6 blend. It was also found that when the two graft products were compoundly used, the compatibilizing effect on the blend was even better.Lastly, PP and EVA, were blended with different loading proportions and then grafted by MAH and GMA simultaneously to prepared a compound matrix compatilizer, The effects of PP/EVA proportions in the compatilizer on the grafting rate and its melt flow rate, etc. were investigated. It was found that when the PP/EVA ratio in the compatilizer was 50/50, the compatibilizing effect on the PP/EVA blend was the best, but the grafting yield was too low because of the increase of side reactions. The melt flow rate of the blend increased with the increase of the EVA content. After grafting, the melting point and the crystallization temperature of the blend increased, tensile and flexural strength improved significantly. The SEM pictures showed that the compatibility of grafted PP/EVA blend was improved, and the number of large particles was significantly reduced. The results also showed that particles were significantly reduced. The results also showed that GMA performed more efficiently in grafting-compatibilization than MAH, no matter in a single matrix or a compound matrix.更多还原