Study On Thermodynamic Properties Of UHMWPE Staple Yarn Reinforced Epoxy Resin Composite Panel

In this paper,the composite material with thickness of 4mm was prepared by hand paste method.The staple fiber webs with different structures were used as reinforcement layer,and 6307 epoxy resin was used as matrix.The paper discussed the process of making the composite material by hand paste method and the enhancement effect of UHMWPE spun yarns with different braided structure on the mechanical properties of composite materials.It was mainly studied the effect of different temperature on the properties of UHMWPE fiber materials and UHMWPE spun yarn reinforced epoxy composites.Then with the method of variance analysis,the paper researched that the influence of different structure yarns on the moldability of composites and the effect of different temperature and structure yarn network on the mechanical properties of the composites.The relationship between the fiber material and the temperature was studied by means of dry heat treatment at 60 ?,80 ?,100 ?,120 ? and 140 ? for 5h,6h,8h,10 h and 12 h.Test items included the longitudinal morphology of the material,the heat shrinkage of the yarn,the thermal analysis of the material,the infrared spectrum,the X-ray diffraction experiment,the breaking strength and the elongation at break.The results showed that the melting point of UHMWPE fiber is about 147.7 ?.And when the temperature was higher than 120 ? for more than 10 h,the performance of UHMWPE fiber would change obviously.Such as the longitudinal crack,the heat shrinkage of the yarn and the vibration of the macromolecule group increased.The fiber crystal structure changed,the fiber breaking strength decreased and the elongation at break increased.The composites were fabricated by hand-paste method.UHMWPE spun yarns were designed into high and low density unidirectional yarn arrangement,no interlaced yarn arrangement,plain structure,scattered fiber,a density of leno structure and cross structure.There were contrast and 10 different structures,different density of composite materials.The reinforcement layer was placed inside the collective material by the quantitative method,and the multi-layer brushing was beneficial to reduce the bubble generation.It was cured by natural curing under normal pressure and oven drying at 40 ?.The study of composite material formation mainly included the thickness of the composite sheet and the positional deviation of the reinforcement layer in the matrix.The results showed that the average thickness of the high density enhancement layer was larger than that of the low density enhancement layer.And the difference of the yarn type structure was not significant.The difference of the fiber strength was the most obvious.If the reinforcement layer had the same structure,the average migration rate of the high density tissue was higher than that of the low density tissue.If the reinforcement layer had the same weaving density,the average deviation rate of the plain weave was the largest.The variance analysis showed that the composite material thickness and the enhancement layer migration rate of the different enhancement layer were significantly different.Study on the enhancement effect of UHMWPE staple yarn showed that the warp of tensile strength,flexural strength,fracture toughness and impact strength of the composites were higher than that of the weft.The enhancement layer had the same structure,and the influence of density on tensile strength was not obvious.The growth rates of tensile strength,flexural strength and impact strength of the composite materials with the lowest density were the most.The tensile strength of the high density plain reinforcement layer was the most,and growth rates of the weft tensile strength,flexural strength and fracture toughness of the leno-reinforced layer were more.The mechanical properties of composites were measured by 100 ?,120 ?,140 ? and 12 h respectively.The results showed that the tensile strength,flexural strength and fracture toughness increased first and then decreased with the temperature increasing,and the maximum reached at 120 ?.While the impact strength showed a downward with the temperature rising.SPSS treatment found that different types of composite materials and temperature had different effects on the mechanical properties,and the difference was significant.But there was no significant difference in the tensile strength,latitude and longitude bending strength and fracture toughness between the three temperatures.