Melt Grafting Modification Of POE By Multi-monomer Technology And The Study Of Its Application In Toughening And Reinforcing Modification Of PA6

Grafting Styrene(St) and Glycidyl methacrylate(GMA) or 2-Hydroxyethyl methacrylate(HEMA) onto ethylene-1-butylene copolymer(POE) were respectively prepared by multi-monomer melt grafting technology in the Haake mixer, and the effect of a series of factors such as monomer content, Dicumyl peroxide(DCP) content, reaction temperature, reaction time and rotor speed on the Grafting Ratio(GR) and Melt Flow Rate(MFR) of the grafted copolymers were studied by FTIR and MFR instruments. In the POE-g-GMA system, the results with the highest GR 0.49% showed that the optimal formula was that when the proportion of POE/GMA/DCP was 50/2.5/0.1 as well as the optimum process parameters were those reaction temperature was 160℃, reaction time was 8 min and rotor speed was 30 r/min. Adding a second monomer St based on the above recipe and processing condition, the GR increased to 0.90% and the MFR was 0.46 g/10min when the mole ratio of St and GMA was 1:1. While in the POE-g-HEMA system, the results that possessed the highest GR 0.40% indicated that the optimal formula of POE/HEMA/DCP was 50/3/0.3 and the optimum process parameters were those reaction temperature was 150℃, reaction time was 10min and rotor speed was 60 r/min. Based on the above recipe and processing condition, the GR increased to 0.73% and the MFR was 0.35 g/10min when a second monomer St was added and the mole ratio of St and GMA was 1:1.Polyamide 6(PA6)/grafted copolymers(with different species and GD) blends were prepared in the twin-screw extruder and the mechanical properties, morphology of notched impact fracture surface, distribution of elastomer and its diameter were investigated. The results revealed that elastomer blends consisting of POE and its grafted copolymers got the best toughening effect while maintained a better tensile strength and flexural strength. When the proportion of PA6/POE-g-(GMA-co-St)/POE was 80/14/6 and PA6/POE-g-(HEMA-co-St)/POE was 80/12/8, the blends got the maximal notched impact strength 23.0 kJ/cm2 and 20.2 kJ/cm2 respectively, which were much higher than that of the blends toughened only with POE or its grafted copolymers. Besides, its notched impact fracture surface was rougher and hiberarchy-obvious; interface of two phases was more illegible; POE distributed more uniformly while its diameter diminished to about 1μm and formed partial networks with PA6 matrix, which predicted a typical toughness rupture.The melting and crystallization behavior of toughened PA6 blends were analyzed by DSC, and it was discovered that elastomer was advantageous to PA6's nucleation but hindered its crystal growth. Comparing the Crystallization degree of different blends,we knew that PA6> PA6/grafted POE blends> PA6/POE> PA6/elatomer blends/POE blends.PA6/elastomer blends/short glass fiber(SGF) composites were prepared in the twin-screw extruder on the basis of toughened PA6, and the effect of different grafted copolymer and SGF content on the mechanical properties, heat resistance(Vicat Softening Temperature), rheological behavior and microstructure of the composites were researched. It revealed that when the SGF content was 40 phr of the polymers, composites with POE-g-(GMA-co-St) maintained the best integrated properties and notched impact strength in normal temperature was 18.9kJ/cm2, tensile strength was 99.2MPa , flexural strength was 128.1MPa and the Vicat softening temperature was 217℃; and the fluidity of the composite in 245℃was the best and it was much senstive to the shear rate; and the notched impact fracture surface was obviously knaggy; and SGFs were highly oriented as well as distributed uniformly in the PA6 matrix and had a reaction with grafted POE which yielded many sediment in the SGF surface; and all of these characters indicated that the composite was toughness-fractured.