The effect of ion implantation, including Ar+ ion with influences (1 × 1013 - 1015 ions/cm2), on the electrical and optical properties of ultrahigh molecular weight polyethylene (UHMWPE) were investigated with pa...The effect of ion implantation, including Ar+ ion with influences (1 × 1013 - 1015 ions/cm2), on the electrical and optical properties of ultrahigh molecular weight polyethylene (UHMWPE) were investigated with particular emphasis placed on the sensor performance to be used in the field of radiation detection. The obtained results focusing on the effect of the different influences showed a significant change in the electrical conductivity, capacitance and loss tangent. The absorption spectra for UHMWPE samples were recorded and the values of the allowed direct and indirect optical energy gap (Eopt)d, (Eopt)in of UHMWPE and energies of the localized states for the virgin and implanted samples were calculated. We found that the optical energy gap values decreased as the radiation dose increased. The results can be explained on the basis of the ion beam radiation-induced damage in the linear chains of UHMWPE, with cross-linking generated after implantation. The observed changes in both the optical and the electrical properties suggest that the UHMWPE film may be considered as an effective material to achieve ion-radiation detection at room temperature.展开更多
The purpose of this multicenter study was to evaluate the clinical performance of an ultrahigh molecular weight polyethylene (UHMWPE) fiber cable for re-attachment of the osteotomized greater trochanter in hip surgery...The purpose of this multicenter study was to evaluate the clinical performance of an ultrahigh molecular weight polyethylene (UHMWPE) fiber cable for re-attachment of the osteotomized greater trochanter in hip surgery. Included in the study were 85 hips that had undergone surgery with greater trochanter osteotomy, including 50 hip arthroplasty procedures and 35 hip osteotomies. The osteotomized greater trochanter was reattached using one or more UHMWPE fiber cables. The bone union and displacement of the greater trochanter were assessed in radiographs for up to 12 months after surgery. Non-union of the osteotomy site occurred in 4.7% of the cases. In approximately 90% of the cases, displacement was less than 2 mm at up to 12 months after surgery. The UHMWPE fiber cable was a good biomaterial for reattaching the osteotomized greater trochanter and may also be an option for osteosynthesis procedures.展开更多
Although the size effects of a filler are closely related to the complex multi-level structures of their polymer composites;unfortunately,such relationships remain poorly understood.In this study,we investigated the e...Although the size effects of a filler are closely related to the complex multi-level structures of their polymer composites;unfortunately,such relationships remain poorly understood.In this study,we investigated the effects of various sizes(40-600 nm)of silicon carbide(SiC)fillers on the wear behavior of ultrahigh molecular weight polyethylene(UHMWPE)in the presence of the silane coupling agent KH-560.All of these SiC fillers improved the wear resistance of UHMWPE significantly,with a medium size(150 nm)being optimal.To examine the reasons for this behavior,we analyzed the multi-level structures of the samples in terms of their matrix structures(crystalline;amorphous;interphase),matrix-filler interactions(physical adsorption;chemical crosslinking;hybrid network)and the external effects of SiC fillers(bearing loads;transferring frictional heat).The high rigidity and thermal conductivity of SiC fillers and,more importantly,the intrinsic characteristics of the matrix structures(larger crystal grains;higher interphase;stronger amorphous entangled networks)were the key parameters affecting the enhancement in the wear-resistance of the UHMWPE.Herein,we also provide interpretations of the corresponding physical effects.Our results should improve our understanding of the structure-property relationships and,thus,should guide the formula design of UHMWPE composites.展开更多
The three stages in the hot-drawing process of ultrahigh-molecular-weight polyethylene gel films can be detected by x-ray diffraction, infrared spectroscopy, birefringence and scanning electron microscopy. In the firs...The three stages in the hot-drawing process of ultrahigh-molecular-weight polyethylene gel films can be detected by x-ray diffraction, infrared spectroscopy, birefringence and scanning electron microscopy. In the first stage of the drawing process, the lamellae in the gel films rotate and/or slip with the b-axis preferentially perpendicular to the drawing direction. With increased drawing, the c-axis of the lamellae become parallel to the stretching direction while unfolding of the chain begins, and the chains of the amorphous phase also orient along the drawing direction in the strain-chain domain. When the draw ratio is large enough, the lamellar structure is transformed into a fibrillar structure in a two-dimensional fashion.展开更多
Polymer matrix types of fiber hybrid composites are key factors to improve ballistic impact damage tolerances.Here we report ballistic penetration damages of Kevlar/ultra-high molecular weight polyethylene(UHMWPE)hybr...Polymer matrix types of fiber hybrid composites are key factors to improve ballistic impact damage tolerances.Here we report ballistic penetration damages of Kevlar/ultra-high molecular weight polyethylene(UHMWPE)hybrid composites with thermoplastic polyurethane(PU)matrix.The hybrid composites were penetrated by fragment-simulating projectiles(FSPs)using an air gun impact system.The effects of stacking sequences on the ballistic performance of hybrid composites were analyzed.Two types of specific energy absorption(the energy absorption per unit area density and the energy absorption per unit thickness)were investigated.It was found that the main damage modes of PU hybrid composites were fiber breakage,matrix damage,fiber pullout and interlayer delamination.The instantaneous deformation could not be used as a reference index for evaluating the ballistic performance of the target plate.The energy absorption process of the PU hybrid composites showed a nonlinear pattern.The hybrid structure affected the specific energy absorption of the materials.展开更多
采用相对分子质量比较了抗氧剂1010和Ciba Irganox B 225混合抗氧剂在超高相对分子质量聚乙烯(UHMWPE)溶解过程中的抗降解作用。结果表明:在UHMWPE溶解过程中,随着温度的升高,加热时间的增长,UHMWPE的相对分子质量有明显的下降;而抗氧...采用相对分子质量比较了抗氧剂1010和Ciba Irganox B 225混合抗氧剂在超高相对分子质量聚乙烯(UHMWPE)溶解过程中的抗降解作用。结果表明:在UHMWPE溶解过程中,随着温度的升高,加热时间的增长,UHMWPE的相对分子质量有明显的下降;而抗氧剂能有效抑制UHMWPE的降解,其用量增加,抑制 UHMWPE降解的作用也随之增大;当加热110 min,温度升至180℃时,加入质量分数为2％的混合抗氧剂, UHMWPE的相对分子质量下降33．9％,而未加混合抗氧剂时,UHMWPE的相对分子质量下降70．2％。相同用量时,混合抗氧剂效果比抗氧剂1010好。展开更多
文摘The effect of ion implantation, including Ar+ ion with influences (1 × 1013 - 1015 ions/cm2), on the electrical and optical properties of ultrahigh molecular weight polyethylene (UHMWPE) were investigated with particular emphasis placed on the sensor performance to be used in the field of radiation detection. The obtained results focusing on the effect of the different influences showed a significant change in the electrical conductivity, capacitance and loss tangent. The absorption spectra for UHMWPE samples were recorded and the values of the allowed direct and indirect optical energy gap (Eopt)d, (Eopt)in of UHMWPE and energies of the localized states for the virgin and implanted samples were calculated. We found that the optical energy gap values decreased as the radiation dose increased. The results can be explained on the basis of the ion beam radiation-induced damage in the linear chains of UHMWPE, with cross-linking generated after implantation. The observed changes in both the optical and the electrical properties suggest that the UHMWPE film may be considered as an effective material to achieve ion-radiation detection at room temperature.
文摘The purpose of this multicenter study was to evaluate the clinical performance of an ultrahigh molecular weight polyethylene (UHMWPE) fiber cable for re-attachment of the osteotomized greater trochanter in hip surgery. Included in the study were 85 hips that had undergone surgery with greater trochanter osteotomy, including 50 hip arthroplasty procedures and 35 hip osteotomies. The osteotomized greater trochanter was reattached using one or more UHMWPE fiber cables. The bone union and displacement of the greater trochanter were assessed in radiographs for up to 12 months after surgery. Non-union of the osteotomy site occurred in 4.7% of the cases. In approximately 90% of the cases, displacement was less than 2 mm at up to 12 months after surgery. The UHMWPE fiber cable was a good biomaterial for reattaching the osteotomized greater trochanter and may also be an option for osteosynthesis procedures.
基金financially supported by the National Natural Science Foundation of China(Grants 21878089 and 21476085)National Key R&D Program of China(2016YFB0302201)the Fundamental Research Funds for the Central Universities(222201717025)。
文摘Although the size effects of a filler are closely related to the complex multi-level structures of their polymer composites;unfortunately,such relationships remain poorly understood.In this study,we investigated the effects of various sizes(40-600 nm)of silicon carbide(SiC)fillers on the wear behavior of ultrahigh molecular weight polyethylene(UHMWPE)in the presence of the silane coupling agent KH-560.All of these SiC fillers improved the wear resistance of UHMWPE significantly,with a medium size(150 nm)being optimal.To examine the reasons for this behavior,we analyzed the multi-level structures of the samples in terms of their matrix structures(crystalline;amorphous;interphase),matrix-filler interactions(physical adsorption;chemical crosslinking;hybrid network)and the external effects of SiC fillers(bearing loads;transferring frictional heat).The high rigidity and thermal conductivity of SiC fillers and,more importantly,the intrinsic characteristics of the matrix structures(larger crystal grains;higher interphase;stronger amorphous entangled networks)were the key parameters affecting the enhancement in the wear-resistance of the UHMWPE.Herein,we also provide interpretations of the corresponding physical effects.Our results should improve our understanding of the structure-property relationships and,thus,should guide the formula design of UHMWPE composites.
文摘The three stages in the hot-drawing process of ultrahigh-molecular-weight polyethylene gel films can be detected by x-ray diffraction, infrared spectroscopy, birefringence and scanning electron microscopy. In the first stage of the drawing process, the lamellae in the gel films rotate and/or slip with the b-axis preferentially perpendicular to the drawing direction. With increased drawing, the c-axis of the lamellae become parallel to the stretching direction while unfolding of the chain begins, and the chains of the amorphous phase also orient along the drawing direction in the strain-chain domain. When the draw ratio is large enough, the lamellar structure is transformed into a fibrillar structure in a two-dimensional fashion.
基金National Natural Science Foundation of China(No.51875099)。
文摘Polymer matrix types of fiber hybrid composites are key factors to improve ballistic impact damage tolerances.Here we report ballistic penetration damages of Kevlar/ultra-high molecular weight polyethylene(UHMWPE)hybrid composites with thermoplastic polyurethane(PU)matrix.The hybrid composites were penetrated by fragment-simulating projectiles(FSPs)using an air gun impact system.The effects of stacking sequences on the ballistic performance of hybrid composites were analyzed.Two types of specific energy absorption(the energy absorption per unit area density and the energy absorption per unit thickness)were investigated.It was found that the main damage modes of PU hybrid composites were fiber breakage,matrix damage,fiber pullout and interlayer delamination.The instantaneous deformation could not be used as a reference index for evaluating the ballistic performance of the target plate.The energy absorption process of the PU hybrid composites showed a nonlinear pattern.The hybrid structure affected the specific energy absorption of the materials.
