Study On Properties Of UHMWPE Fiber And Its Monofilament Filter Cloth Prepared By Melt-Spinning

Due to the high molecular weight,high entanglement of the molecular chain,high degree of orientation and high crystallinity straight chain structure,the ultra-high molecular weight polyethylene(UHMWPE) fiber has excellent mechanical properties,chemical stability, wear-resisting performance and low surface energy.So it is the ideal material for high-performance filter cloth, which is unnmatched by other fibers.In this study, the medium molecular weight polyethylene (MP) and the small molecular weight polyethylene (LP)were used as modifiers into the ultra-high molecular weight polyethylene(UHMWPE)to prepare the UHMWPE fiber by melt spinning method, and weaved monofilament filter cloth which structure is 2/2 twill weave organization by using the UHMWPE fiber. This subject research the modification mechanism of the modifier to the UHMWPE raw materials. The effects of process parameters (tensile temperature, tensile magnification and residence time)on the properties of UHMWPE were investigated. The effects of heat setting process parameters (setting temperature, setting time and setting tension) on the mechanical properties, air permeability, dimensional stability and bubble diameter of UHMWPE monofilament filter were investigated. The relationship between the performance of the cloth and the heat-setting process were setup, and the optimum heat-setting process conditions were screened out.The MP and LP synergistically change the mobility and spinnability of UHMWPE raw materials, and the LP molecular chains cause the UHMWPE crystal grains to be unwound and MP is to reduce the entanglement between the macromolecules in the amorphous region density. But when the amount of addition up to 20, the performance of fiber will be decreased. Under the condition of suitable oil bath temperature, tensile magnification and residence time, the macromolecule chains will direct along the stress direction and the mechanical properties will be greatly improved.If it is in the high temperature for a long time.the macromolecules chains will get pyrolysis and result in invalid slip.If the tensile magnification is too high, the fiber structure of the defect will increase.The experiment find the best temperature of tension is about 90? and the best magnification is about 25 times.The crystallinity and crystallinity of the UHMWPE filter cloth are improved under the appropriate molding temperature, time and warp tension conditions. The structure of the filter cloth becomes more regular, compact and stable, and the pore size is more uniform. And the long time and the high temperature will make the filter cloth fiber molecular chain pyrolysis and recrystallization, accelerat the aging of the filter cloth, result the defects increased and the performance degradation in filter cloth. The optimum heat setting temperature of UHMWPE monofilament filter cloth is about 100?, the best setting time is about 90s and the suitable warp tension is about 100KN.The UHMWPE fiber prepared by Melt spinning method is fully able to meet the requirements of the production of monofilament filter cloth.