Structure And Properties Control Of Uhmwpe Microporous Materials Prepared By High Pressure "Jet Flow" Method

Ultra high molecular weight polyethylene(UHMWPE)molecular chain is linear,its wear-resisting property,low temperature resistance,better chemical stability and other mechanical properties are more than other kinds of plastics.The microporous material made of UHMWPE has good hygiene,good air permeability,good mechanical properties and excellent self-lubricating and non water absorbing properties.It can be used for filtration and separation of liquid and gas.There are many kinds of conventional methods for forming UHMWPE microporous materials,such as long cycle,non environmental protection and so on.In this paper,we propose a high-pressure "Jet Flow" injection compression method to prepare UHMWPE microporous materials.This way has the feature of short cycle,low energy consumption and more hygienic.In this project,through the cross-linking reaction of UHMWPE,the "Jet Flow"particles are more uniform and smaller.And,the properties of microporous materials were adjusted from the aspects of injection direction and molding parameters,so as to obtain a new theory of UHMWPE microporous filter materials prepared by high-pressure "Jet Flow" method.The main study and conclusions includes:(1)The effects of crosslinking on "Jet Flow" state,filling motion and pore formation of UHMWPE were studied.The structure and properties of microporous materials prepared by cross-linking injection molding were compared with those prepared by commercial sintering,experimental sintering and uncrosslinked injection molding.It was concluded that cross-linking could improve the structure and properties of microporous materials.Combined with rheological test,DSC test and XRD test,'the effects of rheological properties and condensed structure changes on the formation of "Jet Flow" particles were studied,and the dynamic pore formation mechanism of microporous materials prepared by high pressure "Jet Flow" method under cross-linking effect was revealed,which was different from that by powder sintering method.(2)The effect of the content of crosslinking agent on the structure and properties of UHMWPE microporous materials was studied,and the optimum amount of crosslinking agent was obtained.(3)The results show that the micro structure of the micro pore sample formed by injection compression molding in the vertical direction is better than that in the axial direction and the radial direction.(4)The effects of injection speed,injection pressure and other process parameters on the pore structure and physical and mechanical properties(compressive strength,water flux)of microporous materials were studied.The comprehensive properties of UHMWPE microporous materials prepared by the optimum parameters are better than those of commercial sintered microporous materials.