Synthesis, Characterization And Application Of Polyolefin Grafted Glycidyl Methacrylate (PO-g-GMA)

Polyolefins have excellent processability, good chemical stability, and low production cost. They are the most widely used commercial polymers in the world. The lack of polar functional groups in the polymer is associated with a low surface energy and limits its use with polar materials. Polyolefin grafted Glycidyl methacrylate (PO-g-GMA) has been studied as a compatilizer. GMA as a grafted monomer increases the molecular polarity of polyethylene. It also provides functional epoxy groups which meet the requirements for mineral-reinforced systems, polymer blends, and co-extruded products. The epoxy groups of GMA can react with amine end groups, carboxyl end groups, and hydroxyl end groups in reactive compatilization. In current, there are few studies about the reaction of PO grafted GMA in melt grafting, even the application of PO-g-GMA is limited to polymer alloy blending, so the study of grafting reaction and the expansion application of PO-g-GMA are mainingful and meritorious. In this work, the melt grafting method are used for the synthesis of various PO-g-GMAs, the quantitative characterization of the degree of grafting of GMA is studied and discussed, the GMA reaction mechanism in melt grafting was analyzed, the PO-g-GMAs were used to compatibilization the PE/MGH high filled composite as the compatibilizer, and the main results are as follows:1. LDPE-g-GMA and (LDPE/LLDPE)-g-GMA, with different degrees of grafting were obtained using melt free-radical grafting of GMA ontoLDPE and LDPE blending LLDPE (LDPE/LLDPE). Non-aqueous titration after purification (D.G.(wt.-%)), infrared spectroscopy after purification (D.G.(IR)) and infrared spectroscopy after heat treatment ([GMA]IR) were used to determine the degree of grafting. D.G.(IR) had a high correlation with [GMA]IR with both LDPE-g-GMA and LLDPE-g-GMA. Unreacted GMA monomer was effectively removed by heat treatment.[GMA]IR could replace D.G.(IR) in characterizing the grafting degree of LDPE-g-GMA and (LDPE/LLDPE)-g-GMA.[GMA]IR was a simple and convenient method of analysis.2. Three different molecular structure POs were grafted GMA general, and these grafting reaction mechanism were analysised also:in melt grafting reaction process, the amount of reacted GMA will be improved once GMA or initiator concentration increase, but the side reactions that crosslink in PE grafting and degradation in PP follow up to serious; with proper concentration of co-monomer styrene (St.) addition, these detrimental side reacteion are inhibited while the amount of reacted GMA is improved.3. The factors in GMA melt grafting reaction, GMA concentration, initiator concentration, co-monomer St.concentration and multi-initiator ratio, were systematic analysised. Co-monomer St. could effectively improve the amount of reacted GMA, increasing the concentration of initiator could improve the amount of grafting GMA also, but there would be decreased when the initiator concentration is to overcorrect.The curve of [GMA]IR and D.G.(IR) were changed in the same direction and dimension ratio with the increasing of concentration of GMA, which was meaning that GMA graft reaction rate and the polymerization reaction rate were linear positive correlation.4. Functional polymers such as polyethylene grafted glycidyl methacrylate (PE-g-GMA) and ethylene-methyl acrylate-glycidyl methacrylate terpolymer (E-MA-GMA) were used as a compatibilizer in the preparation of highly filled composites of polyethylene/magnesium hydroxide (PE/MGH). Comparative studies were performed of the effect of magnesium hydroxide and stearic acid on the interface between a polymer and magnesium hydroxide composite. The effect of polymeric compatibilizers on the properties of the composites was studied using tensile and impact tests, torque rheological analysis, differential scanning calorimetry and environmental scanning electron microscopy (ESEM). The microstructure of highly filled PE/MH composites changed after the addition of functional polymers. The mechanical properties of the composite material increased after compatibilization. The compatibilization processes in PE-g-GMA and E-MA-GMA were different. The grafted polymer was more compatible in polyethylene, which led to polarization of the polymer phase. In contrast, the tercopolymer tended to adhere to the surface of MH particles.