UHMWPE纤维抗蠕变改性的研究进展

超高分子质量聚乙烯(UHMWPE)纤维为三大高性能纤维之一，因其轻质、高强高模等优异性能而得到了广泛应用。但是，UHMWPE纤维的蠕变严重，易造成使用失效，严重限制了其在绳缆等领域的应用。首先对UHMWPE纤维发展历程及其蠕变现象进行了简要介绍，随后对共混、交联、共聚等抗蠕变改性的研究进展进行了系统梳理、对比和总结，最后对抗蠕变UHMWPE纤维的产业化及应用前景进行了展望。     

基于均匀设计的UHMWPE纤维拉伸蠕变性能的测试方法

以1 555 dtex超高相对分子质量聚乙烯(UHMWPE)纤维为例,采用均匀设计探讨了UHMWPE纤维蠕变性能测试方法,通过DPS分析软件对其结果进行多项式回归分析。结果表明:拉伸蠕变性能测试结果的回归模型相关系数为0.996 8,由模型得到的测试参数优化值分别为蠕变载荷210 N(纤维断裂载荷的50%),拉伸速度为197.670 5 mm/min,蠕变时间为70.917 2 min,测试长度为200.481 9 mm,蠕变伸长率为7.301 5%;在蠕变载荷为纤维断裂截荷的50%,拉伸速度为200 mm/min,蠕变时间为70 min,纤维测试长度为200 mm的实测条件下,测得纤维的蠕变伸长率为7.012%,与模型预测值有较好的对应,回归模型有较好的拟合性和稳定性。     

超高分子量聚乙烯纤维蠕变性能研究进展

介绍了超高分子量聚乙烯(UHMWPE)纤维的蠕变机理及蠕变行为;综述了UHMWPE纤维抗蠕变改性方法,即物理改性方法(填充改性和多次拉伸法)和化学改性法(紫外线辐照交联法、硅烷偶联剂法、高能射线辐照法),讨论了各改性方法的工艺特点和处理效果,紫外线辐照交联法应用较为广泛;指出在UHM-WPE纤维抗蠕变性能的研究过程中,应注重改性的效率和成本,以尽快实现抗蠕变改性UHMWPE纤维工艺技术的工业化。     

UHMWPE纤维拉伸蠕变性能的测试方法

以线密度1 776 dtex超高相对分子质量聚乙烯(UHMWPE)纤维为例,采用电子式拉力机测试纤维的拉伸蠕变性能,探讨了操作条件对测试结果的影响。结果表明:UHMWPE纤维的预伸长率和蠕变伸长率随蠕变载荷、蠕变时间和拉伸速度的增大而增大,随纤维测试长度的增大而减小,其中,拉伸速度对纤维的蠕变性能测试有很大影响;建议对GB/T 19975—2005进行修改,对其中的拉伸速度、夹持长度进行限制。     

UHMWPE纤维蠕变性能及其数学模型拟合

测试分析了超高相对分子质量聚乙烯 (UHMWPE)纤维的蠕变性能 ,研究了蠕变与温度、外加应力之间的关系。随环境温度的升高 ,纤维的恒蠕变速率增大 ,抗蠕变断裂时间变小 ,蠕变断裂伸长变大 ;随施加应力的增大 ,纤维的恒蠕变速率增大 ,抗蠕变断裂时间变小 ,蠕变断裂伸长变小。通过计算机编程拟合的蠕变曲线与实测蠕变曲线十分吻合 ,拟合出的材料相关参数与实际测量值相近。     

超临界CO_2预处理对UHMWPE纤维电子束辐照效果的影响

采用正交试验,研究了超临界CO_2预处理工艺(压力、温度、时间)对辐敏剂三羟甲基丙烷三甲基丙烯酸酯(TMPTMA)渗入率及超高相对分子质量聚乙烯(UHMWPE)纤维凝胶含量和蠕变率的影响,并利用Minitab软件分析UHMWPE纤维凝胶含量和蠕变率与TMPTMA渗入率之间的关系,最后通过对UHMWPE纤维各项性能的测定,进一步优化超临界CO_2预处理工艺。研究结果表明:处理温度对TMPTMA的渗入率及UHMWPE纤维凝胶含量和蠕变率影响最大,其次为压力,时间的影响最小;确定了最佳工艺为处理压力30 MPa、温度80℃、时间50 min;TMPTMA渗入率是引起各个影响因素不同水平之间凝胶含量和蠕变率出现差别的重要因素;超临界CO_2预处理对UHMWPE纤维的辐照交联起到了重要的促进作用,使其抗蠕变性能得到很大程度的改善。     

紫外辐照交联改性UHMWPE纤维的研究

选取不同生产阶段的超高相对分子质量聚乙烯(UHMWPE)纤维进行紫外辐照交联改性,探讨了正庚烷浸泡时间、交联剂浓度、紫外辐照时间等因素对交联效果、纤维力学性能及蠕变性能的影响.结果表明:UHMWPE纤维在正庚烷中的最佳浸泡时间为48 h;紫外光最佳辐照改性时间为6 min;与初生纤维和成品纤维相比,相同改性条件下冻胶纤...     

紫外辐射交联改善UHMWPE纤维蠕变性能研究进展

超高分子量聚乙烯(UHMWPE)纤维较差的抗蠕变性能影响了其应用。该文介绍了纤维发生蠕变机理及蠕变行为,综述了采用紫外辐射方法改善UHMWPE纤维蠕变性能的技术进展,并讨论了工艺特点和处理效果。     

多级拉伸中超高相对分子质量聚乙烯纤维的结构与性能研究

采用凝胶纺丝-超拉伸技术纺制了超高相对分子质量聚乙烯(UHMWPE)纤维。采用双折射法、DSC热分析法对不同拉伸级数的纤维进行了结构分析并测试了其力学性能和抗蠕变性能。研究结果表明:随着拉伸倍数的增加,纤维的取向度、结晶度及热性能得到了提高,力学性能和抗蠕变性得到改善,可得到纤维强度大于30cN/dtex,模量超过1200cN/dtex的高性能纤维。     

基于UHMWPE纤维低度交联与表面改性制备高模量、高强度UHMWPE/EP复合材料

从工业化生产应用角度研究电晕处理直接作用于超高分子量聚乙烯(UHMWPE)纤维编织布织布表面，探究纤维表面交联和界面改性对复合材料力学性能的影响。利用X射线光电子能谱(XPS)、傅里叶变换红外光谱(ATR-FTIR)和扫描电镜(SEM)对UHMWPE纤维表面物理性质和化学组成进行表征。采用差示扫描量热仪(DSC)对电晕处理前后纤维结晶度和热稳定性进行表征。当电晕处理功率达到3.0 kW时，UHMWPE-C3.0kW/EP复合材料的冲击强度、弯曲强度和弯曲模量达到了167.4 kJ/m²、121.3 MPa和9.3 GPa,相较于未处理UHMWPE/EP复合材料分别增加了31.5%、64.8%和190.6%。结果表明，通过电晕处理强化了纤维表面与树脂界面黏接强度，有利于复合材料对外力的传递分散，并通过强界面破坏吸收能量及UHMWPE纤维的断裂和形变提高了复合材料的抗冲击和抗弯性能。     

超高分子量聚乙烯纤维性能及应用概述

超高分子量聚乙烯纤维有着高取向度,高结晶度,强力、模量高,抗冲击,耐腐蚀,耐光照,耐挠曲,耐磨损等优点。它的密度比水小,介电性能好。超高分子量聚乙烯纤维的缺点是使用温度不高,耐氧化性能差,抗蠕变性能差,表面加工困难。正是超高分子量聚乙烯纤维自身所具有的这些特点,它在抗冲击防护,低温,耐压,海洋工程,渔业等领域有着广泛地使用。     

UV irradiation and aging effects on nanoscale mechanical properties of ultra high molecular weight polyethylene for biomedical implants

Abstract

As a result of its relatively high strength, high chemical resistance, low creep and low wear rate, ultra high molecular weight polyethylene (UHMWPE) has been widely used as the 'soft' articulating surface for total hip and knee arthroplasty. However, for long term artificial joint replacements, accelerated wear as a result of aging of UHMWPE is one of the most important problems that can lead to joint failure. Therefore, the present work is focused on investigating the effects of thermal and serum aging and UV irradiation dose on the nanomechanical properties (elastic modulus, hardness and visco-elasticity) of UHMWPE (type GUR410) specimens under different deformation rates. The continuous stiffness measurement (CSM) nanoindentation technique is used in the present work to measure the nanomechanical properties. The results show a considerable increase in the nanomechanical properties with increasing deformation rate. It is also demonstrated that the nanomechanical properties of the thermally and serum aged UHMWPE specimens decrease compared to the virgin specimens, while their visco-elastic behaviour increases. For the UV irradiated specimens, the nanohardness and nano-elastic modulus show an increase with irradiation dose especially for small penetration depths. Moreover, a considerable decrease in visco-elastic behaviour was observed for the UV irradiated specimens as a result of the crosslinking effect of the radiation.     

Effects of sunshine UV irradiation on the tensile properties and structure of ultrahigh molecular weight polyethylene fiber

This study investigated sunlight‐simulated ultraviolet (UV) beam irradiation on the tensile properties and structure of ultrahigh molecular weight polyethylene (UHMWPE) fibers. The tensile results showed that after 300 h sunlight UV irradiation, the tensile properties of the UHMWPE fibers were obviously degraded. Investigation of morphology revealed that the crystallinity was slightly increased, whereas the overall orientation and molecular weight of the fibers were decreased. SEM observations indicated that the degradation process was nonuniform throughout the fiber and a change from a ductile to a brittle fracture mechanism was found after UV irradiation. DMA results showed two β‐relaxations and one α‐relaxation in the original single filament, and UV irradiation led to the increased intensity of the high‐temperature β‐relaxation and the lowered position of the low‐temperature β‐relaxation. This indicated that irradiation‐induced molecular scission and branching were located primarily in the amorphous and the interface areas of the fiber. Changes in the thermal behavior were also examined by DSC. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2757–2763, 2003     

Influence of different sterilization procedures on the morphological parameters and mechanical properties of ultra‐high‐molecular‐weight polyethylene

The objectives of this study were to examine the effects of the processing conditions, sterilization, and thermal treatment on the morphological and mechanical properties of ultra‐high‐molecular‐weight polyethylene (UHMWPE) in medical applications by means of thermal analysis, Fourier transform infrared spectroscopy, and nanoindentation. It is well known that manufacturing, irradiation, and thermal treatments significantly alter the microstructure of materials, which results in changes in their mechanical properties. UHMWPE was found to be barely sensitive to processing conditions but strongly influenced by sterilization treatments. Great emphasis was given to the characterization of the so‐called first generation of highly crosslinked UHMWPE because the thermal history of this material differed from that of γ‐irradiated materials. The physical and mechanical properties of UHMWPE were influenced as a result of γ and electron‐beam irradiation and the remelting procedure. Lower crystallinity, different lamellar thickness distributions, and lower hardness and modulus values were estimated. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Wear resistant UHMWPE with high toughness by high temperature melting and subsequent radiation cross-linking

The goal of this study was to create wear resistant ultra high molecular weight polyethylene (UHMWPE) with improved strength and toughness. It was previously demonstrated that high temperature melting (HTM) of UHMWPE at 280-320 °C improved its toughness without detrimentally affecting its wear resistance. We hypothesized that radiation cross-linking after high temperature melting could further improve the wear resistance of UHMWPE, and the loss in toughness by radiation cross-linking could be compensated by the improved toughness achieved by the high temperature melting prior to irradiation. In this work, we demonstrated that irradiation after HTM generated UHMWPE with improved toughness compared to the irradiated UHMWPEs without HTM, partly due to the low cross-link density of irradiated HTM UHMWPE. At a given cross-link density, irradiated HTM UHMWPEs showed higher wear resistance than irradiated UHMWPE. Therefore, successive HTM and radiation cross-linking strategy is promising to create UHMWPE materials with low wear and improved mechanical properties for total joint implants.     

紫外辐射接枝改性UHMWPE纤维表面的研究

采用紫外辐射接枝方法对超高相对分子质量聚乙烯(UHMWPE)纤维表面进行改性。探讨了单体种类及浓度、引发剂、抗氧剂、接枝方法等对UHMWPE纤维表面处理效果的影响,测试了以其作为增强材料的复合材料的层间剪切强度。结果表明:在有氧开放体系下,气相接枝效果好于液相接枝;丙烯酰胺单体的接枝效果优于其它单体;接枝率随接枝单体浓度和接枝时间的增加而增加。采用丙烯酰胺为接枝单体,在光强度为86μW/cm~2条件下,对UHMWPE纤维进行紫外辐射接枝改性,按照一定铺层方式制备的环氧基复合材料的层间剪切强度从未处理的14.59MPa提高到17.36MPa。     

Study on the influence of electron beam irradiation on the thermal,mechanical, and rheological properties of ethylene‐octene copolymer with high comonomer content

Ethylene‐octene copolymer (EOC) was irradiated using electron beam irradiation at different dosages (30, 60, 90, and 120 kGy). Effect of irradiation dosage on thermal and mechanical properties was studied. When compared to low density polyethylene, EOC exhibited higher degree of crosslinking reflected in increased gel content, higher elastic modulus (G′), and lower tan δ obtained by rheology measurement at 150°C. Crosslinking caused improvement in high‐temperature creep and room temperature and also elevated temperature elastic properties. Differential scanning calorimetry revealed that e‐beam irradiation has caused a gradual reduction in crystallinity and a presence of a fraction with higher melting temperature. In the case of EOC, as the extent of crosslinking increased, stress at break showed an increasing trend whereas irradiation dosage had an inverse effect on elongation at break. Radiation dosage has positive effect on thermal stability estimated by thermogravimetric analysis. After 30 min of thermal degradation at 220°C, slightly higher C?O peak for crosslinked sample was found by Fourier transform infrared spectroscopy while for room temperature samples no C?O peak was detected. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

超高相对分子质量聚乙烯长丝蠕变性能的研究

通过悬挂重物一定时间后测试纤维蠕变伸长和用蠕变仪直接测量的方法分别测试了超高相对分子质量聚乙烯长丝和高强涤纶工业丝这两种高强纤维的蠕变性能。从试验中得出超高相对分子质量聚乙烯长丝具有比高强涤纶工业丝更高的断裂强度和弹性模量。两种纤维随悬挂重物时间的延长及重物重量的增加,其断裂强力总体上呈下降趋势,但程度不同。悬挂重物相同时间下,超高相对分子质量聚乙烯长丝伸长较高强涤纶工业丝小,且其形变在外力撤除后难以恢复,产生较大塑性变形,大大影响其力学性能。