Ultradrawing, Thermal and Dynamic Mechanical Properties of Ultra-high Molecular Weight Polyethylene/Carbon Nanotube Fibers Prepared at Varying Formation Temperatures

摘要

The achievable draw ratios (Dra) of ultrahigh molecular weight polyethylene (UHMWPE)/carbon nanotubes (CNTs) as-prepared fibers prepared near the optimum concentration improve consistently as their CNTs concentrations increase up to an optimum value. Moreover, the Dra values of the UHMWPE/CNTs fiber specimens prepared from the optimum composition of the UHMWPE/CNTs gel solutions improve significantly as their spinning formation temperatures reduce to an optimum temperature of 5 . In fact, the D ℃ra value of the UHMWPE/CNTs fiber specimen prepared using the optimum composition and formation temperature is more than 120 % higher than those of the UHMWPE as-prepared fiber specimen prepared at the optimum concentration and formation temperature. As evidenced by DSC analysis, the percentage crystallinity and melting temperature values of the as-prepared UHMWPE/CNTs fibers increase and reduce significantly as their CNTs contents increase, respectively. In contrast, the percentage crystallinity and melting temperature values of the as-prepared UHMWPE/CNTs fibers increase significantly as their formation temperatures increase. Dynamic mechanical analysis of the UHMWPE and UHMWPE/CNTs fiber specimens exhibited an extraordinary high ℃ transition peaked at temperatures near 95- 115 , which increase significantly as their ℃ formation temperatures and/or CNTs contents increase. In order to understand these interesting drawing, thermal and dynamic mechanical properties of the UHMWPE and UHMWPE/CNTs as-prepared fiber specimens, the birefringence, morphological and tensile properties of the as-prepared and drawn fibers were investigated. Possible mechanisms accounting for these interesting properties are proposed.