超高相对分子质量聚乙烯加工及应用进展

综述了超高相对分子质量聚乙烯(UHMWPE)在纤维、薄膜、管材/板材方面的发展现状，以及其加工方法、在不同领域中的改性方法和应用，并对我国今后UHMWPE加工技术与应用前景进行了展望。     

超高分子质量聚乙烯纤维及其复合材料的共混改性

超高分子质量聚乙烯(UHMWPE)纤维是一种重要的战略材料，目前已经广泛应用于防弹背心、安全纺织品、船用绳索和高强度复合材料等领域；但其也存在易蠕变、耐热性差以及再加工、复合困难等问题，亟需高效改性以进一步拓展应用。聚焦近年来UHMWPE的共混改性研究，综述了共混改性对UHMWPE纤维力学、耐热、加工等性能的影响，探讨了共混改性的作用机制，展望了共混改性UHMWPE纤维及其复合材料的应用领域及前景。     

超高分子量聚乙烯/聚丙烯共混改性研究进展

超高分子量聚乙烯(UHMWPE)的加工一直是一个世界性难题。采用聚丙烯(PP)改性UHMWPE可显著提高UHMWPE的加工性能并保持较好的力学性能,因而UHMWPE/PP共混体系的研究受到广泛关注。本文首先介绍了限制UHMWPE加工成型的主要原因,其次从相态结构、流动性能、力学性能及耐磨性能等方面综述了近年来UHMWPE/PP共混改性的研究进展,最后对其发展方向进行了展望。     

超高分子量聚乙烯改性研究进展

针对超高分子量聚乙烯（UHMWPE）熔体流动速率极低、熔点高、熔体粘度大,因而加工成型困难等缺点,综述了提高其加工性能和物理力学性能的物理改性、化学改性、聚合物填充改性及自增强改性等的研究进展,指出了UHMWPE今后的发展方向.     

UHMWPE减摩耐磨改性研究进展

介绍了超高相对分子质量聚乙烯(UHMWPE)的摩擦学理论,综述了近年来对该材料进行减摩耐磨改性的研究进展,重点从无机填料填充改性、表面改性、高分子合金共混改性以及交联改性等方面进行了阐述。最后,对减摩耐磨UHMWPE复合材料的发展趋势、应用前景进行了展望,指出改善UHMWPE复合材料的生物相容性、进一步提高其减摩耐磨性能,并应用于生物医学领域将是今后的研究重点。     

自增塑UHMWPE改性体系的加工性能与力学性能

采用旋转流变仪测定的复数黏度表征UHMWPE体系的加工性能,以改性UHMWPE体系的力学性能作为改性效果的判断依据。结果表明:UHMWPE/PP的加工性能与UHMWPE/B-UHMWPE的力学性能存在互补关系;UHMWPE/PP/B-UHMWPE三元体系能较好地兼顾UHMWPE改性体系的加工性能与力学性能。     

不同成型方式下UHMWPE耐热改性进展

介绍了近年来超高分子量聚乙烯(UHMWPE)在模压成型、挤出成型、注塑成型方面的耐热改性研究进展,分析了采用不同成型方法对UHMWPE耐热改性的方法及改性效果。关于UHMWPE模压与挤出成型的耐热改性方法主要包括物理改性(填充改性、共混改性、共混填充改性)、化学改性(过氧化物交联、偶联剂交联、辐射交联)、聚合填充复合改性,而UHMWPE的注塑成型耐热改性研究较少。对UHMWPE进行耐热改性,加入的改性材料后,能显著提高复合材料耐热性,但是,部分材料的加入却降低了UHMWPE耐磨性、抗冲击性等性能,需要对UHMWPE注塑成型的耐热改性及改性材料的选用进一步研究。最后,对UHMWPE的耐热改性的发展趋势进行了展望。     

超高分子量聚乙烯成型加工及改性

介绍了近些年超高分子量聚乙烯（UHMWPE）的成型加工方法，由于UHMWPE熔体粘度极高，成型加工困难，通常采用模压成型，限制了其应用领域；通过综述中低分子量聚乙烯，聚丙烯，液晶聚合物及无机填料等改性UHMWPE所取得的成绩，指出解开UHMWPE的链缠结是改性最核心的问题。     

超高分子量聚乙烯的应用及改性研究进展

介绍了超高分子量聚乙烯（UHMWPE）的性能和用途,综述了提高UHMWPE加工性能和物理性能的物理改性、化学改性、聚合物填充改性以及白增强改性方法的研究进展。指出了其今后的发展方向。     

超高相对分子质量聚乙烯改性研究进展

综述了近年来超高相对分子质量聚乙烯(UHMWPE)改性的研究进展。对超高相对分子质量聚乙烯的改性主要包括机械性能与加工性能两个方面。对其机械性能的改性方法包括化学改性和填充改性,加工性能的改性包括共混改性法和润滑剂改性法。     

超高分子量聚乙烯的成型工艺及改性研究进展

本文介绍了超高分子量聚乙烯材料的基本性能,并由其性能决定的成型工艺,由于超高分子量聚乙烯熔体粘度极高,加工比较困难,限制了其的应用;通过综述近年来的超高分子量聚乙烯的改性研究进展,认为只有进行有力的改性研究,才可以将超高分子量聚乙烯的优异性能得到更为广泛研究和应用。     

Exploring the entangled state and molecular weight of UHMWPE on the microstructure and mechanical properties of HDPE/UHMWPE blends

Three types of ultra-high molecular weight polyethylene (UHMWPE) with different entangled state and molecular weight were blended with high-density polyethylene (HDPE) matrix by melt blending. Rheology, 2D-SAXS, 2D-WAXD, DSC, and mechanical tests were used to study the evolution and difference of microstructure and mechanical properties of the blends. The addition of weakly entangled UHMWPE enhanced the chain diffusion and chain orientation ability under a specific flow field. Thus, the rheological properties and mechanical properties of the blends were improved with the mix of weakly entangled UHMWPE. The mechanical properties enhancement effect of HDPE/UHMWPE blends with weakly entangled UHMWPE was owing to the shish-kebab structure formed in the injection molding process. The molecular chains of UHMWPE with a low degree of entanglement and high molecular weight increased the lamella size and crystallinity of the blends during processing. This leads to the formation of more oriented shish structures and more kebab lamella. Besides, the molecular chains of weakly entangled UHMWPE were better interlocked and intertwined with other polyethylene chains in the amorphous region, acting as the tie molecules, significantly improving the impact resistance.     

超高相对分子质量聚乙烯的耐磨性改性研究进展

综述了近年来超高相对分子质量聚乙烯(PE-UHMW)耐磨性改性的研究进展,介绍了物理共混改性法(无机填料填充和聚合物共混)和化学改性法(交联和等离子体处理)在PE-UHMW耐磨性改性方面的应用,讨论了各种改性方法对其耐磨性改性的改性机理和改性效果,并对PE-UHMW耐磨性改性的发展趋势作了展望。     

Sliding wear behaviour of oriented ultrahigh molecular weight polyethylene

The impact of processing‐induced chain orientation on the sliding wear behaviour of ultrahigh molecular weight polyethylene (UHMWPE) was investigated. The orientation of the molecular network of UHMWPE was done by means of uniaxial tension up to different residual strains. We found that high residual strain levels (higher than 0.45) enabled the sliding dissipated energy of UHMWPE to be decreased in dry conditions. In particular, oriented UHMWPE with a residual strain of 0.85 exhibited, at 500 000 sliding cycles in dry conditions, a decrease in volumetric wear loss by a factor of 3.3 and 19.4 compared with the reference UHMWPE tested in directions parallel and perpendicular to the chain direction, respectively. It is argued that oriented UHMWPE exhibits less adhesion during interfacial wear than the reference material, and hence orientation of UHMWPE bulk may be an alternative treatment to crosslinking for dry sliding conditions. In the case of sliding testing conducted in Ringer's solution, the benefit of the initial chain orientation was quite weak due to a lubrication effect of the solution that markedly limited the effect of chain orientation on the sliding behaviour.     

UHMWPE/CNTs复合体系及其纤维的研究进展

综述了超高分子量聚乙烯(UHMWPE)、碳纳米管(CNTs)、UHMWPE/CNTs复合体系及其纤维的研究现状,以及CNTs的添加对UHMWPE/CNTs复合体系及其纤维性能的影响;添加CNTs可有效提高UHM-WPE的耐磨性、电学性能、力学性能以及UHMWPE纤维的抗蠕变性能和热稳定性能;指出CNTs对UHM-WPE改性过程中存在的主要问题是CNTs分散性差,CNTs的生产成本高,UHMWPE/CNTs的改性机理有待进一步深入,并进一步拓宽UHMWPE/CNTs复合体系及其纤维的应用领域。     

Effect of surface modification of Kevlar fibre on friction and wear properties of UHMWPE composites

Abstract

The effects of Kevlar fibre additions and, particularly, the surface modification of the Kevlar fibres, on the sliding wear behaviour of the ultra high molecular weight polyethylene (UHMWPE) composites were investigated. The results showed that the sliding friction coefficient of the UHMWPE composites increased with the fibre content increase. The wear resistance of the UHMWPE composite was highest when the Kevlar fibre content was ～10 vol.-% and decreased as the applied normal load was increased. It was found that the silane modification of the Kevlar fibres improved the wear resistance and tensile strength of the UHMWPE composites as well.     

Properties of compression molded ultra‐high molecular weight polyethylene products pretreated by eccentric rotor extrusion

Low processing efficiency and fusion defects limit the application of ultra‐high molecular weight polyethylene (UHMWPE) in artificial joint implants. These problems result from the high melt viscosity of UHMWPE. Here, we use an eccentric rotor extruder (ERE) based on elongational flow to pretreat UHMWPE. Compression molded UHMWPE is obtained without and with ERE pretreatment (EP‐UHMWPE). The processing efficiency of EP‐UHMWPE is improved compared with direct compression molded UHMWPE. This is because the preheating time can be omitted during the molding process, and the residence time of UHMWPE in the extruder is less than 90 s. The mechanical properties and friction resistance of EP‐UHMWPE are significantly improved compared with those of direct compression molded UHMWPE. The yield strength increases from 21 MPa to 23 MPa, the tensile strength increases from 36 MPa to 46 MPa, the elongation at break increases from 610% to 700%, and the abrasion loss decreases from 1.73 mg/1000 r to 0.93 mg/1000 r when UHMWPE is subjected to ERE pretreatment. We attribute these improvements to the elongational flow enhancing the orientation and disentanglement of UHMWPE molecular chains, which in turn improves particle fusion. The molecular weight is well maintained when subjected to ERE pretreatment. UHMWPE components pretreated by ERE have good prospects in artificial joint implants. © 2019 Society of Chemical Industry     

UHMWPE/PEG共混方式及配比对UHMWPE缠结行为及性能的影响

超高分子量聚乙烯（UHMWPE）是常用的高性能聚合物。由于高黏度的影响,极大地限制了其加工成型与应用。聚乙二醇（PEG）具有高流动性,被广泛用来改善UHMWPE的流变行为,但复合材料中添加相的分散效果对材料的性能有重要影响。采用干粉混合、溶液混合、熔融挤出共混等方式制备了不同配比UHMWPE/PEG复合材料。基于熔融拉伸实验研究了共混方式及配比对UHMWPE缠结行为及性能的影响。结果表明,PEG的加入降低了复合材料的链缠结密度。三种混合方式中,加入5%PEG时干粉混合与挤出混合解缠作用较明显,链缠结密度均降低26%左右。     

Surface modification of ultra‐high‐molecular‐weight polyethylene. II. Effect on the physicomechanical and tribological properties of ultra‐high‐molecular‐weight polyethylene/poly(ethylene terephthalate) composites

We performed surface modification of ultra‐high‐molecular‐weight polyethylene (UHMWPE) through chromic acid etching, with the aim of improving the performance of its composites with poly(ethylene terephthalate) (PET) fibers. In this article, we report on the morphology and physicomechanical and tribological properties of modified UHMWPE/PET composites. Composites containing chemically modified UHMWPE had higher impact properties than those based on unmodified UHMWPE because of improved interfacial bonding between the polymer matrix and the fibers and better dispersion of the fibers within the modified UHMWPE matrix. Chemical modification of UHMWPE before the introduction of PET fibers resulted in composites exhibiting improved wear resistance compared to the base material and compared to unmodified UHMWPE/PET composites. On the basis of the morphological studies of worn samples, microploughing and fatigue failure associated with microcracking were identified as the principle wear mechanisms. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006