| In this paper, grafting of maleic anhydride(MAH) onto high density polyethylene(HDPE) performed in melt state through the mechanical force initiation by increasing the screw rotation speed of co-rotating twin-screw extruder and through a compounded initiation by adding a certain initiator and increasing the screw rotation speed was investigated; the grafting of maleic anhydride(MAH) and γ -methacryloxypropyltrimethoxysilane(A174) onto high density polyethylene(HDPE) performed in melt state through the mechanical force initiation was also investigated. The results show that with increase of the screw rotation speed and with increase of the grafting temperature, the grafting degree and melt flow index of the grafted products are obviously increased. The crosslinking reaction can be prevented easily by increasing the screw rotation speed of twin-screw extruder; the grafting degree of the product(HDPE-g-MAH) amounts to 1.34%, its melt-flow index is between 0.3～ 0.6g/10min and its gel content is less than 0.9%. The presence of A174 is helpful to improve the percentage of MAH grafting, and the grafting degree of the product(HDPE-g-MAH-A174) is greater than 0.59%; its melt-flow index is between 0.3～0.53g/10min.The effects of the grafted products on the mechanical properties of the HDPE/PA66 and HDPE/GF blends were tested by means of mechanical testing. The results show that grafted product (HDPE-g-MAH) can obviously improve the impact strength of the HDPE/PA66 blend, which is 6.5 times than that of unimproved one. And the tensile strength, flexural strength and Izod notched impact strength of the HDPE/GF blend, which contains the mechanical force initiation grafted product (HDPE-g-MAH-A174), are 1.7, 1.3 and 2.6 times than of unimproved one respectively.The effects of the interfacial bonding strength and the cooling shrinkage stress of the specimen during molding process on the morphology of the fracture specimens...
|
PDF Full Text Request