聚烯烃作为重要的合成材料之一，直接影响国民消费水平的提高及国民经济发展。但聚烯烃材料在拥有十分广泛的应用的同时，其非极性使它的表面加工性能、粘结性能及与其它材料复合性能存在一些不足。利用极性单体对其进行熔融接枝改性是改善聚烯烃极性的重要方法。本文首先深入研究了甲基丙烯酸缩水甘油酯（GMA）对聚烯烃的接枝机理，提出在GMA接枝聚烯烃的过程中若温度超过某一临界温度（解聚温度，Tc）时已经接枝上的PGMA链会发生解聚现象，导致GMA接枝率的降低。向体系中加入苯乙烯（St）作为助单体可以有效抑制接枝PGMA的解聚现象，从而将GMA的接枝率维持在较高水平。在此机理的基础上，提出了两种有效的提高GMA接枝聚烯烃的接枝率的方法，分别为控制温度或控制St的加料时机。在对GMA接枝聚烯烃机理研究的基础上，系统研究了一系列丙烯酸酯类单体，包括甲基丙烯酸缩水甘油酯（GMA）、甲基丙烯酸羟丙酯（HPMA）、甲基丙烯酸羟乙酯（HEMA）、甲基丙烯酸乙酯（EMA）、甲基丙烯酸甲酯（MMA）及丙烯酸羟乙酯（HEA）等，对聚烯烃的熔融接枝机理。对比研究发现，丙烯酸酯类接枝聚烯烃的过程中普遍存在解聚现象，但解聚温度的高低不同。解聚温度的高低主要受侧基位阻和特殊相互作用基团的影响。对于不同丙烯酸酯类单体，添加苯乙烯（St）作为助单体所起到的作用也各不相同，可以用Q-e法则对其进行解释。基于塑料回收利用的目的，本文致力于利用多单体熔融接枝物增容PO/PS/PA6三元共混物。在对GMA接枝聚烯烃的机理深入研究的基础上，制备了PP-g-(GMA-co-St)，并将其作为相容剂增容PP/PS/PA6体系。利用铺展因子的概念对PP-g-(GMA-co-St)和PP-g-GMA、PP-g-St对体系的不同增容效果进行了解释。改变加工方法也可能给相形貌带来动力学的影响。同时共混物的流变性能也与相形貌进行了对比研究。制备了Versify-g-(GMA-co-St)，并以此增容Versify/PS/PA6共混物，其相形貌发展同样符合“铺展因子”的预测。讨论了其力学性能与相形貌的关系，通过添加Versify-g-(GMA-co-St)，可以得到拉伸强度较高的Versify/PS/PA6共混物。
Polyolefin is one of the most important categories of synthetic material, which plays a very important role in the national economic development. Although it has various applications, the lack of polarity limited its use. To improve the polarity of polyolefin, it is quite useful to graft polar monomers onto the polyolefin backbone. In this paper, the styrene (St) assisted melt grafting of glycidyl methacrylate (GMA) on polyolefin was carried out by Haake mixer, and the grafting mechanism was investigated and reconsidered. It was revealed that there is equilibrium of grafting of GMA and depolymerization of grafted PGMA chains in the GMA/polyolefin grafting process, which was affected by both of the temperature and GMA concentration. It was found that the depolymerization of PGMA grafted on polyolefin occurred at the temperature above ceiling temperature (Tc) of PGMA and dominated the grafting process before the addition of styrene monomer, which induced the decrease in grafting ratio of GMA. Adding styrene as co-monomer could promote the equilibrium moving forward to form the St-GMA chains so that the grafting ratio was greatly improved. It is proved that either controlling the reacting temperature below Tc or changing the feeding order of styrene and GMA is effective to attain high grafting ratio of GMA on polyolefin.On the basis of the investigation of mechanism of the GMA melt grafting, the melt grafting of other acrylate monomers, including HPMA, HEMA, EMA, MMA, and HEA, were also investigated. It is found that the depolymerization also exists for melt grafting of the other acrylate monomers, and the Tc of the particular monomer depends on the steric hindrance and the special interactions between monomers. The styrene was applied to assist the grafting of acrylate monomers, and the effectiveness can be predicted by the Q-e rule.The PP-g-(GMA-co-St), PP-g-GMA and PP-g-St graft copolymers were prepared by Haake mixer and added in PP/PS/PA6 ternary blends as a compatibilizer. Because the compatibility of PP-g-GMA, PP-g-St, and PP-g-(GMA-co-St) for PP/PA6 phases and PP/PS phases is different, the different phase morphologies, such as encapsulating, anti-encapsulating, partial-encapsulating and separating, could be conducted. The spreading coefficient was calculated by the interfacial tensions to predict the phase morphologies. Adding compatibilizer would change the interfacial tensions and the phase morphologies of the ternary blends, which could also been predicted. The two-step blending was also carried out and showed the influence of the dynamic factors on the phase morphologies. The rheological characterization of the blends with different morphologies was carried out and it is found that the compatibilizers increased the complex viscosity by changing the phase morphologies.Versify-g-(GMA-co-St) was also prepared to compatibilize PP/PS/PA6 ternary blends. The phase domain size decreased a lot and the tensile strength was improved. The Versify-g-(GMA-co-St) with different GMA/St content led to different phase morphologies and mechanical properties as the compatibilizer.
