Comparative Study On Modification Of Wood-flour PVC Composite By PA/ACR/CPE

With the gradual acceptance of polyvinyl chloride(PVC)wood plastic composites,the development of PVC wood plastic composite products is moving faster and faster.However,because of its poor impact strength,the application range of PVC wood plastic composites is greatly limited.In this paper,wood fiber was treated with different conditions to improve the processability of PVC wood plastic composites,so as to determine the good and stable processing conditions.Then,two kinds of impact modifiers,acrylic resin(ACR)and chlorinated polyethylene(CPE)were introduced to PVC wood plastic composites to modify the PVC wood plastic composites to improve the impact resistance of the material.Meanwhile,engineering plastics,low melting point polyamide(PA)with three kinds of compatibilizer were used to imporve the toughness of wood flourpolyvinyl chloride composites(WF-PVC).To have a better comparison of ACR and CPE in different performance in the system,the static mechanical properties,dynamic mechanical properties and torque rheological properties were investigated.the results showed that:(1)in the presence of ACR,the impact strength of WF-PVC increased by 15%;(2)two kinds of modifier decreased the glass transition temperature of WF-PVC;(3)after adding ACR and CPE to PVC wood plastic composites,the equilibrium torque decreased by 6N·m and 2.7N·m respectively,which enhanced the fluidity of melt system during processing.For low melting point polyamide-WF-PVC composites,three kinds of compatibilizers,maleic anhydride grafted ethylene vinyl acetate copolymer(EVA-g-MAH),maleic anhydride grafted polypropylene(PP-g-MAH)and maleic anhydride grafted polyolefin elastomer(POE-g-MAH)were introduced to the preparation process of the composites.The mechanical results showed that the addition of low melting point nylon and compatibilizer increased mechanical properties of WF-PVC composites,the impact strength of WF-PVC composite increased by 18.76% for the incorporation of low melting point nylon,as well as the flexural strength increased by 13.65%.Nylon-WF-PVC composites with EVA-g-MAH compatibilizer present much higher mechanical characteristic,the impact strength of the composite was increased by 39.02% and the flexural strength was increased by 16.37%.The dynamic mechanical analysis test showed that the addition of low melting point nylon and compatibilizer reduced the storage modulus of the composites,especially in the temperature range of 30°C to 90°C.The torque rheometer test results showed that the balance torque of WF-PVC composites was decreased due to the addition of low melting nylon.In contrast,the incorporation of EVA-g-MAH and POE-g-MAH increased the balance torque.The torque rheometer results indicated compatibilizers had some negative effects on the processing properties of WFPVC composites.SEM images showed EVA-g-MAH and POE-g-MAH were effective compatibilizers to nylon and WF-PVC blends and could decrease the particle size of nylon on continuous phase of WF-PVC,and thus enhance the mechanical properties of WF-PVC composites obviously.Water absorption test results showed that the water absorption of WF-PVC increased with the addition of low melting nylon.By using the compatibilizer,it is expected that the interfacial compatibility of components of the composites could be improved,and in turn the water absorption of the Nylon-WF-PVC was reduced and mechanical properties were increased.