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.

Systemic investigation of the influence of the plain and functionalized carbon nanotube (CNT) contents on the ultradrawing properties of ultrahigh molecular weight polyethylene/carbon nanotubes (UHMWPE/CNTs, FC y ) and UHMWPE/functionalized CNTs (FC fx-y ) as-prepared fibers are reported. In a way similar to those found for the orientation factor values, the achievable draw ratios (D ra ) of the FC y and FC fx-y as-prepared fibers approached a maximum value as their CNT and/or functionalized CNT contents reached their corresponding optimum values. The maximum D ra values obtained for FC fx-0.001 as-prepared fiber specimens prepared at varying maleic anhydride grafted polyethylene (PE -g-MAH )/modified CNTs weight ratios were significantly higher that of the FC 0.0015 as-prepared fiber specimen prepared at the optimum plain CNT content. Tensile property analysis further suggested that excellent orientation and tensile properties of the drawn FC y and FC fx-y fibers can be obtained by ultradraw-ing the fibers prepared at their optimum plain CNT and/or functionalized CNT contents. To understand the interesting orientation, ultradrawing and tensile properties of FC y and FC fx-y fiber specimens, FTIR, specific surface area, and SEM morphology analysis of the plain and functionalized CNTs were performed in this study. POLYM. ENG. SCI., 51:687-696, 2011. ª FIG. 6. Tensile strength and modulus values of FC 0 , FC 0.0005 , FC 0.0001 , FC 0.0015 , FC 0.002 , FC f1-0.0005 , FC f1-0.001 , FC f1-0.0015 , FC f1-0.002 , FC f2-0.0005 , FC f2-0.001 , FC f2-0.0015 , FC f2-0.002 , FC f3-0.0005 , FC f3-0.001 , FC f3-0.0015 , FC f3-0.002 , FC f4-0.0005 , FC f4-0.001 , FC f4-0.0015 and FC f4-0.002 fiber specimens with varying draw ratios.

The influence of formation temperature on the ultradrawing properties of ultrahigh‐molecular‐weight polyethylene/carbon nanotube (UHMWPE/CNT) fiber specimens is investigated. Gel solutions of UHMWPE/CNT with various CNT contents were gel‐spun at the optimum concentration and temperature but were cooled at varying formation temperatures in order to improve the ultradrawing and tensile properties of the UHMWPE/CNT composite fibers. The achievable draw ratio (Dra) values of UHMWPE/CNT as‐prepared fibers reach a maximum when they are prepared with the optimum CNT content and formation temperature. The Dra value of UHMWPE/CNT as‐prepared fibers produced using the optimum CNT content and formation temperature is about 33% higher than that of UHMWPE as‐prepared fibers produced using the optimum concentration and formation temperature. The percentage crystallinity (Wc) and melting temperature (Tm) of UHMWPE/CNT as‐prepared fiber specimens increase significantly as the formation temperature increases. In contrast, Wc increases but Tm decreases significantly as the CNT content increases. Dynamic mechanical analysis of UHMWPE and UHMWPE/CNT fiber specimens exhibits particularly high α‐transition and low β‐transition, wherein the peak temperatures of α‐transition and β‐transition increase dramatically as the formation temperature increases and/or CNT content decreases. In order to understand these interesting drawing, thermal and dynamic mechanical properties of the UHMWPE and UHMWPE/CNT as‐prepared fiber specimens, birefringence, morphological and tensile studies of as‐prepared and drawn fibers were carried out. Possible mechanisms accounting for these interesting properties are proposed. Copyright © 2010 Society of Chemical Industry

The influences of the dispersion level of carbon nanotubes (CNTs) and functionalized CNTs on the transmittance properties of ultrahigh‐molecular weight polyethylene (UHMWPE) gel solutions and on ultradrawing properties of their as‐prepared fibers are reported. The transmittance properties suggest that the dispersion level of functionalized CNTs in UHMWPE/functionalized CNTs gel solution is significantly better than plain CNTs in UHMWPE/CNTs gel solutions. The orientation factors, achievable draw ratios, tensile strength (σf), and modulus (E) values of UHMWPE/CNTs (FxCy) and UHMWPE/functionalized CNTs (FxCf‐y) as‐prepared fiber specimens reached a maximum value as their CNT and functionalized CNT contents approached optimum contents at 0.00015 and 0.0001 wt%, respectively. The σf and E values of both FxC0.0012 and FxCf‐0.001 series fiber specimens prepared at their optimum CNT and functionalized CNT contents reached another maximum as their UHMWPE approached optimum UHMWPE concentration of 1.7 wt%. Possible reasons accounting for these interesting properties are proposed. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers

In this study, helium/oxygen/nitrogen (He/O2/N2)‐plasma was used to etch/modify the surface of ultra‐high‐molecular‐weight polyethylene (UHMWPE) fiber. After coated with polyurethane (PU), the plasma treated UHMWPE fabrics were laminated. It was found that the values of peeling strength between the laminated UHMWPE fabrics treated with He/O2/N2‐plasma were significantly higher (3–4 times) than that between pristine fabrics. The hydrophilic property and the value of the surface roughness of the UHMWPE fibers increased significantly after treated with He/O2/N2‐plasma. The mechanism of the oxidation/degradation of the polymers on the surface of the UHMWPE fiber during He/O2/N2‐plasma treatment was suggested. In addition, it was found that the higher content of functional groups (carbonyl, aldehyde, and carboxylic acid) on fiber surface and the higher value of surface roughness of the UHMWPE fiber treated with He/O2/N2‐plasma could significantly improve the adhesion‐strength of the laminated UHMWPE fabric. Especially, the micro‐aperture on the surface of UHMWPE fiber caused by the strenuous etching of He/O2/N2‐plasma treatment was also an important factor on improving the adhesion‐strength between the laminated UHMWPE fabrics. Copyright © 2010 John Wiley & Sons, Ltd.