Preparation And Characterization Of High-Concentration Gel Spinning Of UHMWPE Fiber

Ultrahigh molecular weight polyethylene (UHMWPE) fiber has plenty of excellent properties and has been used widely in the fields of military protection, aerospace engineering, ocean engineering and other special areas. One of the main methods to prepare UHMWPE fiber is gel spinning. However, it needs large amount of extractant in the extraction process because the content of the solvent in the gel fiber is too high, and consequently lead to a high cost, low production efficiency and high energy consumption, it's not conducive to the development of low-carbon economy.In this study, the concentrations of 18wt%,26wt%,34wt% UHMWPE gel were prepared and different preparation techniques were compared. Moreover, the influences of extraction conditions on gel fiber with different concentrations were investigated during the extraction processes respectively. Differential Scanning Calorimeter (DSC), WAXD and tensile test were used to characterize the crystallization behavior and mechanical property of the fibers. The conclusions were as follows.1 High-concentration UHMWPE gel belonged to Bingham fluid and all non-Newtonian index of different concentration gel showed a trend of first increase and then decrease with increasing gel temperature. The structural viscosity index increased with decreasing UHMWPE gel concentration and increasing gel temperature.2 The influences of extraction conditions on gel fiber with different concentrations were investigated during the extraction processes respectively, The results indicated that the optimum extraction temperature and ultrasonic extraction time are 60℃and 15 minutes respectively for the different concentrations UHMWPE gel, and the best extraction ratio for 34wt% concentration gel fiber was 20:1, and high concentration of gel fiber could greatly reduce the amount of extractant in the extraction process.3 DSC and WAXD results indicated that the crystallization rate was increased by the UHMWPE fiber prepared by gel spinning with high concentration.4 The results derived from mechanical tests on UHMWPE fibers indicated that the creep-resistance and heat-resistance behavior were improved significantly with the increase of UHMWPE gel solids content, decomposition temperature Td was also increased. Mechanical test showed that the fiber from the solid content of 26% of the UHMWPE filament fiber and stretch 30 times, the tensile strength was 22.1 cN/dtex, Young's modulus of 560.2 cN/dtex, the fiber from the solid content of 34 of the UHMWPE filament fiber and stretch 30 times, the tensile strength was 20.2 cN/dtex, Young's modulus of 530.5 cN/dtex. It was found that UHMWPE fiber of high concentration obtained high strength and high modulus.