Study On Preparation And Properties Of PA66/UHMMPE Blends

This paper is based on matrix of polyamide66(PA66), by using blend of ultra-high molecular weight polyethylene (UHMWPE) with high density polyethylene (HDPE) as modifier to improve the disadvstage of PA66in impact strength, high water absorption and so on and. Some properties of PA66/PE blends were tested, such as mechanical properties, melt flowability, water absorption, microstructure, and crystalline properties et al.By using melting grafting reaction method, the glycidyl methacrylate (GMA) grafted HDPE (HDPE-g-GMA) was prepared. The influences of different factors on percent grafting were investigated and optimized respectively, such as amount of monomer and initiating agent, reaction-temperature and reaction-time. After that by adding the selected HDPE-g-GMA with different percent grafting, the PA66/PE blends were prepared and their properties were tested. The results showed that the properties of PA66/PE blends achieved optimum at the condition, in which the amount of GMA was ranged at5-7phr, DCP at0.5phr and the reaction time was around15～20minutes and the reaction temperature was about180℃.There were different grades of HDPE blended with UHMWPE respectively. The effect of UHMWPE/HDPE mass ratio on the properties of PA66/PE blends was investigated. It was indicated that using selected HDPE1#. the PA66blends with UHMWPE/HDPE (mass ratio30/70) could achieve better comprehensive mechanical properties.The effect of PA66/PE? mass ratio on properties of PA66blends was investigated. The optimal integrative performance was obtained with composition PA66/PE? mass ratio from80/20to70/30. The results of crystallization properties of PA66/PE2were indicated that the melting behaviors were independent either of PA66or PE2. The molecular chain movement of PA66was restricted by PE2, and the nucleation rate of PA66was decreased, while the nucleation rate of PE2was increased.It was investigated that the effect of HDPE-g-GMA content on the performance of PA66/PE? blends. When the HDPE-g-GMA content around12phr, it could better improve the compatibility and interfacial adhesion strength of PA66/PE2, with balanced performance. The crystallization property of PA66was restricted by HDPE-g-GMA, the crystallization enthalpy of PA66was decreased with the HDPE-g-GMA content increasing.The effect of different types of compatibilizer on properties of PA66/PE? blends was investigated. There were experimental prepared HDPE-g-GMA and the other four different commercial compatibilizers respectively used in PA66/PE2blends. The comparative results showed that all compatibilizers played a certain roles in PA66/PE2, especially the maleic anhydride grafted ethylene copolymer was the best. The crystallization properties were analyzed via differential scanning calorimetry (DSC). The results showed that the melt viscosity was increased and the activity of macromolecular chains of PA66was decreased by adding of compatibilizer agent. The degree of crystallinity of PA66was decreased, and crystallization rate and crystallization temperature was decreased.The effect of SiO2on PA66/PE2blends was studied. The results showed that:(1) By adding small amount of SiO2, the strength and toughness of the PA66blends were enhanced obviously. By using the silane coupling agent treated SiO2, the interfacial adhesion strength of PA66and PF2was enhanced. With increasing content of SiO2, the properties of PA66blends were improved in mechanical properties and heat resistance.(2) The nucleation rate and crystallinity of PA66were increased by adding of SiO2, while, the crystallization temperature of PA66got a little change. The Crystallization temperature and crystal growth rate of polyethylene were increased by adding of SiO2.