多元聚合物的共混增容，不仅对于制备新型高性能聚合物材料具有重要科学意义和应用价值，而且在塑料回收再利用等环境材料领域亦有重要应用。本论文以聚丙烯（PP）、尼龙6（PA6）和聚苯乙烯（PS）组成的三元共混物为主要研究对象，深入研究了多单体接枝制备的PP接枝物对PA6/PP/PS共混物的增容机理，通过引入含不同含量的无规分布乙烯链段的聚丙烯共聚物(co-PP)制备出了具有较高韧性的共混物材料。同时深入研究了分散相组分比和投料方式对共混物相形态和力学性能的影响。本论文还将含多官能团的单体与助单体共同熔融接枝PP，制备出含长支链结构的支化PP，讨论了单体用量、官能度和单体结构等对接枝物的长支链含量、分子量和热稳定性等的影响。主要进展和成果如下：采用马来酸酐(MAH)-苯乙烯(St)多单体熔融接枝制备的接枝物PP-g-(MAH-co-St)或co-PP-g-(MAH-co-St)作为增容剂分别来增容PA6/PP和PA6/PS/PP共混物体系。以co-PP代替PP进行多单体接枝明显地提高了MAH的接枝率。随共混物中接枝物含量的增加及co-PP中乙烯含量的提高，共混物的相容性得到了显著的改善、制备出了高韧性的共混物合金材料，其拉伸强度接近纯PA6而冲击强度和断裂伸长率可达数倍以上。以PP/PS/PA6三元混合物为模型，系统研究了组分比及投料顺序对三元体系的相形态和力学性能的影响。结果表明，组分比和投料顺序对不相容体系影响不大，而增容体系的相形态和力学性能相差较大。PA6，PS和增容剂先共混的体系其拉伸强度和弯曲强度更好。此外，本文通过多单体熔融接枝的方法将多官能团单体接枝到PP主链，既提高了多官能团单体的接枝率，也促进了PP的β成核结晶，使PP的热稳定性提高了30oC以上。通过此方法改性PP，其分子量增加，分子量分布变宽，且具有一定的长支链含量。单体含量增加有利于提高接枝率和长支链含量。流变学和红外光谱等综合分析表明，制备长支链聚丙烯选用官能度大且空间位阻小的1,6-己二醇二丙烯酸酯（HDDA）为好。

The compatibilization of multiple component polymer blends could be used to solve the problems of recycling and reusing of thermoplastics and obtaining new polymeric materials. The purpose of this thesis is to study the free radical melt-grafting of functional monomer-styrene (St) multi-monomer system onto polypropylene (PP) and investigate the compatibilization of polyamide-6 (PA6)/ polypropylene (PP)/polystyrene (PS) ternary blend. Ethylene-propylene copolymer (co-PP) was introduced to the blend system to enhance the mechanical properties and prepare new polymeric alloys with high toughenss. The influnces of component ratio of minor phases and charge sequence on the morphology and mechanical properties were discussed in detail. Besides, free radical melt-grafting of the polyfunctional monomers (PFM) onto PP in the presence of St were used to prepare long chain branched (LCB) PP. The effect of monomer concentration, functionality and the chemical structure of the functional monomer on the thermal stability, LCB content, molecular weight and molecular weight distribution were also studied.The main achievements are as follows:It was found that the graft degree of Maleic anhydride (MAH) monomer was significantly enhanced when co-PP and Styrene (St) were added to prepare the grafted polymer, PP-g-(MAH-co-St) and co-PP-g-(MAH-co-St). The graft degree of MAH in PP(co-PP)-g-(MAH-co-St) was almost 3 times of that prepared by the radical grafting of single MAH onto PP. The degradation of PP was also depressed. PP (co-PP) with more ethylene content would be grafted with more monomers. The compatibility of both the binary PA6/PP blend and ternary PA6/PS/PP blend systems was remarkably improvedd when the grafted PP(co-PP) as the compatibilizer, was added into the immiscible blend systems. The influences of both ethylene content in co-PP and blend composition on the performance were investigated. More compatibilizer concentration and co-PP with more ethylene content could greatly improve the mechanical performance of the blend systems. Significant toughening that the elongation at break of the compatibilized blends increases by dozens of times of the uncompatibilized is achieved.Influences of both component ratio of minor phases and charge sequence on the morphology evolution and mechanical performance in PP/PS/PA6 ternary blends were investigated.For uncompatibilized blends, the phase morphology presented a core-shell morphology with PS as shell and PA6 as core in the PP matrix, in spite of the component ratio and charge sequence. The shell thickened and droplet size decreased with increasing the PS/PA6 component ratio. While for compatibilized blends, the addition of compatibilizers resulted in a significant reduction of the dispersed droplet size, and the encapsulation structure of the dispersed phases was greatly dependent on the charge sequence. When the addition of PA6, g-PP and PP are preceded, the encapsulation structure reversed into the structure of the PA6 encapsulated PS phase, which led to better tensile and flexural strength of the blends.It was also found that the free radical melt-grafting of the polyfunctional monomers (PFM) onto PP in the presence of St not only enhanced the graft degree of PFM onto PP backbones, but also well induce the β form PP crystals and improved the thermal stability of grafted PP even by 70oC. Grafted PP prepared by multi-monomer grafting can also increase the molecular weight and molecular weight distribution. Investigations on the rheological properties of grafted PP indicated the existence of LCB structure. With increasing the St concentration, the graft degree of HDDA increased, melt flow rate (MFR) of the grafted PP decreased and more LCB generated during melt grafting. PFM with more functional groups and low steric hindrance, such as hexanediol diacrylate (HDDA), are more effectively to prepare grafted PP with more LCB contents and longer branches.