Manufacturing of Ultra-high Molecular Weight Polyethylene Fiber Reinforced Tape and the Loss of Strength

Due to the low density and excellent mechanical proper-ties,high performance fiber reinforced materials have aconsiderable application in the area of high technologyand dally usage.In this paper,the Ultra-high Molecu-lar Weight Polyethylene(UHMWPE)fiber reinforcedPE tape prepared with the method of powder impregnat-ion was studied.The effect of impregnate length and thetensile force of the yarn on the fiber content as well as on the strength and modulus of the tape were discussed.Calculation shows that the strength and the modulus ofthe ULMWPE fiber can keep about 85％ after it undergothe process.

PREPARATION OF MICROPOROUS ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENE (UHMWPE) BY THERMALLY INDUCED PHASE SEPARATION OF A UHMWPE/LIQUID PARAFFIN MIXTURE

Ultra-high molecular weight polyethylene (UHMWPE) with a microporous structure was prepared via thermally induced phase separation (TIPS).Liquid paraffin (LP) was used as a diluent in the preparation of microporous UHMWPE. Small angle laser light scattering (SALLS) and differential scanning calorimetry (DSC) were used to determine the phase separation temperatures,i.e.the cloud points and the dynamic crystallization temperatures,respectively.It was found that the cloudI points were coincident with the cryst...

Structure and Properties of Self-reinforced Material Made from Ultra-high Molecular Weight Polyethylene-montmorillonite Nanocomposite

High-strength and high-modulus ultra-high molecular weight polyethylene(UHMWPE), named self-reinforced material, was obtained by the elongation of UHMWPE-montmorillonite nanocomposite at melting temperature. According to the scanning electron microscope(SEM) analysis, a great deal of fibrillar texture formed in the direction of elongation, and the tensile fractured surface was similar to that of highly oriented fiber. The transmission electron microscope(TEM) and selective area electron diffraction(SAED) analyses reveal that the reinforced phase of the self-reinforced material is an extended chain crystal and its size is about 50_200 nm wide and several microns long, and the montmorillonite layers are broken up to pieces in the size from 100 to 10 nm. The broken layers which have a huge surface area interacting strongly with macromolecules reduces the entanglement density of UHMWPE and induces the chain orientation in flow field. It is supposed that the astriction of montmorillonite layers to polyethylene chains is not only end-tethered but also side-tethered. The differential scan calorimetry(DSC) analysis shows that there are two endothermal peaks for the self-reinforced material, of which the peak at a higher temperature(136.4 ℃) is ascribed to the melting of the reinforced phase.

Ultra-High Molecular Weight Polyethylene Tape Applied for Distal Humeral Condyle Fracture around Total Elbow Arthroplasty in Patients with Rheumatoid Arthritis: Report of Two Cases

Managing fractures of distal humerus in patients with rheumatoid arthritis (RA) is technically challenging. Total elbow arthroplasty (TEA) is one of the treatment options for these fractures. While elbow motion is largely regained by TEA, comminuted condyle fragments are often ignored. Although numerous approaches for repair of condylar fragments around TEA are described, any universal fixation strategy for these fractures has not been established. This report describes, for the first time, application of an ultra-high molecular weight polyethylene (UHMWPE) tape for the treatment of distal humerus fracture in 2 patients with rheumatic elbow arthropathy. The post-operative clinical courses were good. Radiographs showed bony union of the condylar fragments without loosening in two cases. Because of its flat configuration, softness, and flexibility, UHMWPE tape is a promising material for stabilizing fracture of the distal humerus associated with TEA.

PREPARATION AND CHARACTERIZATION OF ULTRA-HIGH MOLECULAR WEIGHT POLY(ETHYLENE TEREPHTHALATE)(PET)FIBER

This paper reports the spinning and drawing behavior of Ultra-high Molecular Weight polyethylene Terephthalate) (UHMW-PET) fibers. The as-spun fibers were produced by dry-jet wet spinning of a 15%-17% solution in 50:50(v:v) trifluroroacetic acid and dichloromethane. Both molecular weight and polymer solution concentration have marked effect on the drawability of the as-spun-fibers. The maximum extension drawing ratio (EDRmax) of as-spun fiber increases with increasing molecular weight, whereas optimal concentration to achieve the EDRmax of as-spun fibers decreases with increasing molecular weight. Drawing speed and temperature during the first step have remarkable effect on the drawability of these fiber during the second step. Relatively lower drawing temperature and drawing speed (19 ℃ , 60 mm/min) during the first drawing step was beneficial to mechanical properties of ultimate fibers. At the range of 210 ℃ to 230 ℃, the draw ratio (DR) during the second step increases with increasing temperature.

Optimum Combination of Femoral Head Size, Femoral Head Material, and Acetabular Cup Liner’s Highly-Cross-Linked Polyethylene Brand for Hip Implant

Clinical two-dimensional linear wear rate data for acetabular cup liners fabricated using approved brands of highly cross-linked ultra-high-molecular-weight polyethylene, as reported in 39 articles in the literature, were analyzed using a statistical technique called response surface methodology. The output was a series comprising16 acceptable combinations of femoral head diameter (HD), femoral head material (HM), and HXLPE brand (PB), each of which would yield the optimum wear rate (herein taken to be a wear rate of practically zero). An example of such a combination is 28- mm-diameter Oxinium? femoral head articulated against an acetabular cup liner fabricated from ReflectionTM HXLPE. The findings in this work may guide an orthopaedic surgeon’s selection of the combination of HD, HM, and PB to use in a primary total hip joint replacement.

Compression Molded Ultra High Molecular Weight Polyethylene-Hydroxyapatite-Aluminum Oxide-Carbon Nanotube Hybrid Composites for Hard Tissue Replacement

Ultra high molecular weight polyethylene （UHMWPE） is widely used for articulating surfaces in total hip and knee replacements. In the present work, UHMWPE based polymer composites were synthesized by synergistic reinforcing of bioactive hydroxyapatite （HA）, bioinert aluminum oxide （Al2O3）, and carbon nanotubes （CNTs） using compression molding. Phase and microstructural analysis suggests retention of UHMWPE and reinforcing phases in the compression molded composites. Microstructural analysis elicited variation in densification due to the size effect of the reinforcing particles. The hybrid composites exhibited hardness, elastic modulus and toughness comparable to that of UHMWPE. The interfacial effect of reinforcement phases has evinced the effectiveness of Al2O3 over HA and CNT reinforcements, depicting synergistic enhancement in hardness and elastic modulus. Weak interfacial bonding of polymer matrix with HA and CNT requires utilization of coupling agents to achieve enhanced mechanical properties without deteriorating cytocompatible properties.

Improving the Stab-Resistance Performance of Ultra High Molecular Weight Polyethylene Fabric Intercalated with Nano-Silica-Fluid

High performance fibers impregnated by shear thickening fluids(STFs) have been recognized as a kind of latent stab-resistant materials. In our work, the rheological properties of various nano-silica particles in diffierent carriers were first investigated, some of which showed the typical characteristic of shear thickening phenomena.And then, the effiects of add-on and surface hydrophilicity of silica particles, the type and concentration of the carriers were discussed in detail. It was found that the systems of hydrophilic silica in ethylene glycol, butylenes glycol and polyethylene glycol(PEG) demonstrated shear thickening; moreover, the reversibility of rheological behaviors of hydrophilic silica-PEG300 suspensions indicated energy dissipation existed within a circulation of shear stress. Furthermore, the detail mechanism of STF based nano-silica particles was explored and a process diagram was presented. Finally, the stab-resistance and morphology of cutting edge of ultra high molecular weight polyethylene(UHMWPE) fabric impregnated STF composites were investigated and the results were analyzed.The higher silica add-on was benefit to the improvement of the stab resistance of the composites.

Progressive Failure Analysis of Quasi-isotropic Self-reinforced Polyethylene Composites by Comparing Unsupervised and Supervised Classifications of Acoustic Emission Data

Unsupervised and supervised pattern recognition( PR)techniques are used to classify the acoustic emission( AE) data originating from the quasi-isotropic self-reinforced polyethylene composites,in order to identify the various mechanisms in the multiangle-ply thermoplastic composites. Ultra-high molecular weight polyethylene / low density polyethylene( UHMWPE / LDPE)composites were made and tested under quasi-static tensile load. The failure process was monitored by the AE technique. The collected AE signals were classified by unsupervised and supervised PR techniques, respectively. AE signals were clustered with unsupervised PR scheme automatically and mathematically. While in the supervised PR scheme,the labeled AE data from simple lay-up UHMWPE / LDPE laminates were utilized as the reference data.Comparison was drawn according to the analytical results. Fracture surfaces of the UHMWPE / LDPE specimens were observed by a scanning electron microscope( SEM) for some physical support. By combining both classification results with the observation results,correlations were established between the AE signal classes and their originating damage modes. The comparison between the two classifying schemes showed a good agreement in the main damage modes and their failure process. It indicates both PR techniques are powerful for the complicated thermoplastic composites. Supervised PR scheme can lead to a more precise classification in that a suitable reference data set is input.

硅酮粉改性超高分子量聚乙烯及其熔体纺丝加工性能

针对超高分子量聚乙烯(PE-UHMW)熔体加工性能差的问题,应用硅酮粉,采用熔融共混方法对PE-UHMW进行改性,以提高其熔体加工时的流动性。通过扫描电子显微镜与能量色散谱(EDS)表征了硅酮粉在PE-UHMW中的分布,并采用熔体速率测试、旋转流变测试,分析了硅酮粉含量对PE-UHMW熔体流动速率与流变性能的影响。对改性后的PE-UHMW采用熔体纺丝法制备了PE-UHMW单丝,并进行了拉伸强度测试。实验结果表明,随着硅酮粉的增加,其分散性逐渐变差,PE-UHMW熔体流动速率随硅酮粉含量先增加后降低,当硅酮粉质量分数达到4%,其熔体流动速率最高,复数黏度与储能模量最低,5%质量分数的硅酮粉在PE-UHMW基体中团聚较明显,改性后的PE-UHMW熔体流动性降低。熔体纺丝实验结果表明改性后的PE-UHMW可以通过普通单螺杆挤出机熔融挤出初生丝,经超倍热拉伸可以制备高强度单丝。当拉伸倍率为36时,质量分数3%的硅酮粉改性PE-UHMW单丝拉伸强度最高,可达1565MPa。因此综合考虑加工性能与单丝强度,采用质量分数3%的硅酮粉改性PE-UHMW较合适。

聚乙烯纤维在混凝土中的应用研究进展

综述了超高相对分子质量聚乙烯纤维及其他聚乙烯纤维对混凝土性能的影响,以及在混凝土开发中的应用研究进展。聚乙烯纤维的桥接作用可阻止混凝土裂纹的产生及扩展,提高混凝土的力学性能和耐腐蚀性能,一方面为聚乙烯纤维在建筑领域的应用提供了可能,另一方面也为超高性能混凝土的开发提供了机遇。应加强聚乙烯纤维增强混凝土的系列化、标准化研究,尽快实现工业化。

我国超高分子量聚乙烯纤维的发展现状与建议

超高分子量聚乙烯纤维因优异性能在航空航天、军事防护、海洋工程及纺织等领域具有广泛的应用前景,是世界各国竞相发展的战略性新材料。本文梳理了我国超高分子量聚乙烯纤维发展历程,总结了当前产业发展现状,分析了存在的问题,并对未来发展提出建议。

初生态低缠结超高分子量聚乙烯催化剂研究进展

超高分子量聚乙烯(UHMWPE)具有高耐磨性、高强度和刚度、轻质、耐腐蚀、低摩擦系数、生物相容性等特点,作为一种优异的工程塑料广泛应用于高端新材料等各领域,而调控高分子链的缠结程度对于更好地应用UHMWPE至关重要。从均相催化和非均相催化两方面综述了制备初生态低缠结UHMWPE的催化剂技术的研究进展,其中,单中心催化体系和修饰型Ziegler-Natta催化剂在制备初生态低缠结UHMWPE的工业应用中前景广阔。

双等离子体改性超高分子量聚乙烯复合材料的弹道响应

为揭示双等离子体改性对超高分子量聚乙烯(UHMWPE)复合材料冲击性能的影响,采用真空辅助树脂灌注成型技术(VARI)制成UHMWPE复合材料,借助原子力显微镜等手段对改性前后的纤维表面进行观测,探究复合材料在低速及高速冲击时的抗冲击性能以及防弹机制。低速冲击载荷作为响应值构筑响应曲面模型,高速摄影机捕捉子弹侵彻改性前后复合材料的过程,分析板材的吸能情况并对侵彻后的试样进行表面观测。结果表明:未改性板材通过各层振荡式波动以形成严重分层来耗散能量;改性后的材料能有效地包覆住子弹,背弹面表层纤维呈现原纤化,断口处出现树脂大量富集,阻抗作用增强,吸能值较未改性材料提高45.59%。

闪蒸纺UHMWPE/HDPE共混纤维的制备及性能研究

为提高闪蒸纺纤维束的力学强度,将力学性能更为优异的超高相对分子质量聚乙烯(UHMWPE)与高密度聚乙烯(HDPE)共混,通过闪蒸纺丝方法制备UHMWPE/HDPE共混纤维束,采用扫描电子显微镜、差示扫描量热仪、X射线衍射仪和万能试验机等探究UHMWPE的引入对共混纤维束形貌、熔融结晶行为、聚集态结构和力学性能的影响。结果表明:闪蒸纺丝制备HDPE/UHMWPE共混纤维束时,随着纺丝液中UHMWPE质量分数由1%增至5%,溶液黏度增大,共混纤维束单丝直径逐渐增大,当UHMWPE质量分数为7%时,纺丝液会因黏度过大而无法纺丝;随着UHMWPE含量的增加,HDPE/UHMWPE共混纤维束的结晶度和取向度降低,力学性能增大,当纺丝液中UHMWPE质量分数为5%时,共混纤维束结晶度和取向因子分别为74.2%和0.46,拉伸强度为118.9 MPa,较纯HDPE纤维束提高了84.9%。

活性炭/超高分子量聚乙烯耐热性研究

为了提高超高分子量聚乙烯(UHMWPE)的耐热性,采用超级电容活性炭(微米级)对UHMWPE进行填充改性,制备活性炭/UHMWPE复合材料。通过热重(TG/DTG)测试和维卡软化点温度测试分析了复合体系的热性能;同时研究了活性炭含量对UHMWPE的电学性能、冲击性能、表面及摩擦系数的影响。结果表明:活性炭填充可使UHMWPE材料失重5%时的分解温度提高17.44℃,维卡软化点提高了约18℃;且活性炭对UHMWPE复合体系的抗静电性、冲击性能、表面均有比较明显的改善。

混杂方式对CF/UHMWPEF混杂复合材料力学性能的影响

本文通过碳纤维 /超高分子量聚乙烯纤维混杂复合材料的力学性能试验及结果比较,分析了三种混杂方式对该类复合材料的力学性能的影响。结果表明,不同混杂方式的碳纤维 /超高分子量聚乙烯纤维复合材料具有各自的力学特点。

高温环境对防弹插板抗弹性能影响分析

采用M80弹(7.62 mm×51 mm NATO)分别对常温和高温(55℃)下的防弹插板进行实弹射击试验,以研究高温环境对防弹插板抗弹性能的影响。通过分析试验时防弹插板弹击瞬间凹陷值,同时结合聚氨酯树脂的剥离强度、超高分子量聚乙烯纤维层压板剥离强度和弯曲强度的测试结果对高温下抗弹性能变化原因进行了研究。结果表明:高温下防弹插板抗弹性能明显下降,相对于常温下每发弹的弹击瞬间凹陷值增加了2~5 mm。其主要原因是超高分子量聚乙烯纤维层压板在高温下抵抗变形的能力发生明显下降,从而导致防弹插板的弹击瞬间凹陷值增大。

电子束辐照超高分子量聚乙烯在加速老化过程中的自由基演变

经过辐照处理的医用超高分子量聚乙烯(UHMWPE)必须通过加速老化试验的验证才能达到植入人体使用的要求,但在加速老化过程中,UHMWPE材料的自由基演化机制尚不明确。本研究从自由基角度出发,对现有加速老化方法的效果进行了系统分析。利用电子顺磁共振波谱研究了电子束辐照交联UHMWPE在加速老化过程中的自由基浓度和组成的变化,分析了自由基在该过程中的演变机理,对比分析了自由基在室温空气和70℃氮气中的演变机理。结果表明:加速老化评估方法有很大的局限性,辐照交联UHMWPE表层和内部的自由基在室温空气环境中的演变与在加速老化环境中的演变有显著区别,氧诱导自由基(OIR)的生成率在室温空气环境中约为2%,在加速老化环境中约为0.3%。OIR自由基在室温空气中会稳定存在,而在加速老化环境中会被快速氧化。

超高分子量聚乙烯分子量与熔点的定量线性关系

人工关节是超高分子量聚乙烯(UHMWPE)重要的高附加值应用,其中Ⅰ型关节和Ⅱ型关节对UHMWPE的分子量要求约为4.5×10~6和7.5×10~6,准确测试这类UHMWPE的分子量重要但并不容易。分析了黏度法测分子量的理论,在可接受的假设下肯定了黏度法可准确测得UHMWPE的分子量。同时,从Ziegler-Natta催化剂的聚合原理出发,推导并验证了UHMWPE的分子量与熔点的定量线性关系。