An investigation of the influence of the contents of original and modified attapulgite (ATP) on the ultradrawing properties of ultrahigh-molecular-weight polyethylene (UHMWPE)/ATP (FA x ) and UHMWPE/modified ATP (FA mx ) as-prepared fibers is reported. Similar to what is found for the orientation factor values, the achievable draw ratios (D ra ) of the FA x and FA mx as-prepared fibers approach a maximum value as the original ATP and/or modified ATP contents reach their corresponding optimum values. The maximum D ra value obtained for FA mx as-prepared fiber specimens is significantly higher than that for FA x as-prepared fiber specimens prepared at the optimum original ATP content. Similar to what is found for the orientation factors and achievable drawing properties, the tensile strength (σ f ) and initial modulus (E) of both drawn F 2 A x and F 2 A mx fiber series specimens with a fixed draw ratio reach maximum values as the original and/or modified ATP contents approach the optimum values, respectively. The σ f and E values of the F 2 A mx fiber specimens are always significantly higher than those of the corresponding F 2 A x fiber specimens prepared at the same draw ratios and ATP contents but without being modified. To understand the interesting ultradrawing, orientation and tensile properties of FA x and FA mx fiber specimens, Fourier transform infrared spectral, specific surface area, transmission electron microscopic and elemental analyses of the original and modified ATPs were performed.

Ultrahigh molecular weight polyethylene (UHMWPE)/nanosilica (F2Sy) and UHMWPE/modified nanosilica (F2Smx‐y) as‐prepared fibers were prepared by spinning of F2Sy and F2Smx‐y gel solutions, respectively. Modified nanosilica particles were prepared by grafting maleic anhydride grafted polyethylenes onto nanosilica particles. The achievable draw ratios (Dra) of F2Sy and F2Smx‐y as‐prepared fibers approached a maximal value as the original and modified nanosilica contents reached corresponding optimum values; the maximal Dra value obtained for F2Smx‐y as‐prepared fiber specimens was significantly higher than that of the F2Sy as‐prepared fiber specimens prepared at the optimum nanosilica content. The melting temperature and evaluated lamellar thickness values of F2Sy and F2Smx‐y as‐prepared fiber series specimens decrease, but crystallinity values increase significantly, as their original and modified nanosilica contents respectively increase. Similar to the achievable drawing properties of the as‐prepared fibers, the orientation factor, tensile strength (σf) and initial modulus (E) values of both drawn F2Sy and F2Smx‐y fiber series specimens with a fixed draw ratio reach a maximal value as the original and/or modified nanosilica contents approach the optimum values; the σf and E values of the drawn F2Smx‐y fiber specimens are significantly higher than those of the corresponding drawn F2Sy fiber specimens prepared at the same draw ratios and nanosilica contents but without being modified. To understand the interesting ultradrawing, thermal, orientation and tensile properties of F2Sy and F2Smx‐y fiber specimens, Fourier transform infrared, specific surface area and transmission electron microscopy analyses of the original and modified nanosilica were performed in this study. © 2012 Society of Chemical Industry

The Fourier transform infrared results suggest that the carboxylic acid groups of poly(lactic acid) (PLA) molecules react with the epoxy groups of molecules of Ethylene Glycidyl Methacrylate Copolymer (EGMC) during the reactive extrusion processes of PLA x EGMC y specimens. The tensile and tear strength values of PLA x-EGMC y blown-film specimens in machine and transverse directions improve significantly, and reach their maximal values as their EGMC contents approach an optimum value of 6 wt.%. The melt shear viscosity values of PLA x EGMC y resins, measured at varying shear rates, are significantly higher than those of the PLA resin, and increase consistently with their EGMC contents. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) of PLA and PLA x EGMC y specimens reveal that the percentage crystallinity, peak melting temperature, and onset recrystallization temperature values of PLA x EGMC y specimens reduce gradually as their EGMC contents increase. In contrast, the glass transition temperatures of PLA x-EGMC y specimens increase gradually in conjunction with their EGMC contents. Demarcated porous morphology with several connected fungi-decomposed cavities was found on the surfaces of the PLA x EGMC y specimens after being buried for specific amounts of time, in which the sizes of the fungi-decomposed cavities found on the surfaces of buried PLA x EGMC y specimens reduce significantly as their EGMC contents increase. Further DMA and morphological analysis of PLA x EGMC y specimens reveal that the EGMC molecules are compatible with PLA molecules at EGMC contents equal to or less than 2 wt.% because no phaseseparated EGMC droplets and tan δ transitions were found on fracture surfaces and tan δ curves of PLA x-EGMC y specimens, respectively. The possible reasons for these remarkable properties of the PLA/EGMC specimens are proposed in this study.

Tensile strength and modulus values of UHMWPE, UHMWPE/ANC, UHMWPE/ATANC and UHMWPE/FANCmx fibers with varying draw ratios.

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