Study On Toughening And Reinforcing Of PLA/PC Composites

With the development of science and technology, the plastic is widely used in the field oftraditional industries, such as agriculture, industry, energy and the field of new technologies,such as electronics, aerospace, information technology.However the vast majority of plasticproducts are difficult to degrade, it is seriously harmful to the environment. As a greenbiodegradable polymer, poly(lactic acid)(PLA) has attracted more and more attentionPolycarbonate (PC) as a superior performance of engineering plastics is widely used inelectrical appliances, office equipments, constructions, packaging and daily consumer goods.PLA/PC (polylactic acid/polycarbonate) is partially degraded as a modified composite and theburden of the environment can be reduced, at the same time the applications of PLA also canbe expanded.Firstly, a series of PLA/PC blends was prepared by melting extrusion. Effect of PLA/PCproportion on mechanical properties, heat deflection temperature and melt index of the blendswere studied. On this basis, PLA/PC of30/70proportion was selected to be toughened andreinforced. In this paper, E-MA-GMA, E-MA-MAH, E-BA and EVA-g-MAH were separatelyused to toughen PLA/PC (30/70) blends. Effect of toughening agents’ content on mechanicalproperties, heat deflection temperature and melt index of the blends were studied, glasstransition temperature,and micro morphology were analyzed by DSC and SEM. Study showedthat:(1) The effect of toughening blends, E-MA-GMA and E-BA were the most obvious, thephase domains was decreased and the glass transition temperature was closed, it proved thetwo-phasecapacitive was increased;(2) When content of E-MA-GMA was6wt%and E-BAwas4wt%, notched impact strength of the blends was reached778to884J/m, which was9to10times higher than that of pure PLA/PC(30/70) blends, while strength and modulus weredecreased to a certain extent. Two compatible agents whose toughening effect was better thanthe others was selected to be mixed (total amount of the two components was6wt%, PLA/PCaggregates with a100%gauge). Effect of ration of E-MA-GMA and E-BA on mechanicalproperties was researched. The effect that the ethylene and E-MA-GMA were used together was further investigated. It showed that: notched impact strength of the blends was reached to990J/m when the ratio of E-MA-GMA and E-BA was4:2. Heat deflection temperature couldbe reached103°C when the content of HDPE was3wt%.Secondly, glass fiber (GF) was used to reinforce PLA/PC/E-MA-GMA (30/70/6) blendsby melting extrusion. Effect of types of coupling agents (KH550, KH560, KH570and titanatecoupling agent), content of coupling agents and glass fiber on mechanical properties and meltindex of the composites were studied, micro morphology was analyzed by SEM. The resultshowed that: the interfacial adhesion of glass fiber and composite materials could besignificantly improved especially when the content of KH560was0.3wt%. It can be seen thatthe fiberglass’ surface was rough treated with KH560by scanning electron microscopy, thesurface of GF had more base resin materials. The lexural strength and flexural modulus of thecomposites were increased by52.6%and130%, tensile strength and tensile modulus wereincreased by91.6%and96%respectively when the content of GF was25wt%.