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.

Temperature Effect on the Conformation Transition of Ultra-high Molecular Weight Polyethylene/Polypropylene Blends Undergoing Continuous Volume Extensional Flow:A Mesoscopic Simulation

Due to the multiformity and complexity of chain conformation under external flow and the challenge of systematically investigating the transient conformation and dynamic evolution process of polymer chains at the molecular level by means of present experimental techniques,a universal description of both chain conformation and dynamics with respect to continuous volume extensional flow(CVEF)is still absent.Taking into account the temperature effect,we performed dissipative particle dynamics(DPD)simulations with the particles corresponding to the repeat units of polymers over a wide temperature range and analyzed the correlation with the conformational properties of ultra-high molecular weight polyethylene/polypropylene(UHMWPE/PP)blend in response to the CVEF.With time evolution,the polymer chains become highly oriented parallel to the flow direction instead of the initial random coiling and self-aggregation.It is found that a high temperature is necessary for more substantial compactness to take place than low temperature.The low-k plateau and low-k peak in structure factor S(k)curves suggest a low degree of conformational diversity and a high degree of chain stretching.It is also concluded that the intra-molecular C-C bond interaction is the main driving force for the dynamics process of the chain conformations undergoing CVEF,where the motion of the alkyl chains is seriously restricted owing to the increase in bond interaction potential,resulting in a reduction of the difference in diffusion rates among alkyl chains.

Hot-Drawing of Ultrahigh-Molecular-Weight Polyethylene Gel Films

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.

Cyclic Pulsating Pressure Enhanced Segregating Structuration of Ultra-High Molecular Weight Polyethylene/Graphene Composites as High-performance Light-Weight EMI Shields

Currently,the enhancement in electromagnetic interference(EMI)performance of polymeric composite generally relies on either improving electrical conductivity(σ)for stronger electromagnetic(EM)reflections or tailoring structure for higher EM resonances.Herein,we proposed a novel technique called cyclic pulsating pressure enhanced segregating structuration(CPP-SS),which can reinforce these two factors simultaneously.The structural information was supplied by optical microscopy(OM)and scanning electron microscopy(SEM),both of which confirmed the formation and evolution of segregate structured ultra-high molecular weight polyethylene(UHMWPE)/graphene composites.Then,the result showed that CPP-SS can significantly improve theσof samples.Ultimately,advanced specific EMI shielding efficiency of 31.1 d B/mm was achieved for UHMWPE/graphene composite at 1-mm thickness and a low graphene loading of 5 wt%.Meanwhile,it also confirmed that the intrinsic disadvantage of poor mechanical properties of conventional segregated structure composites can be surpassed.This work is believed to provide a fundamental understanding of the structural and performance evolutions of segregated structured composites prepared under CPPSS,and to bring us a simple and efficient approach for fabricating high-performance,strong and light-weight polymeric EMI shields.

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.

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.

茂金属聚乙烯薄膜料结构与性能

对3种茂金属聚乙烯薄膜料的基础性能、分子量及分布、熔融行为、力学性能和光学性能进行了分析测试,考察了不同工艺下制得的茂金属聚乙烯薄膜料的结构与性能的关系。结果表明:三种薄膜料的分子量分布均比较窄,呈单峰分布,且密度在0.921g/cm^(3)左右,其中具有更低分子量和更高支化度的3~#茂金属聚乙烯薄膜料具有更好的加工性能,并且其断裂标称应变较高、鱼眼少、雾度低。

不同老化方法对聚乙烯地膜结构和性能的影响

聚乙烯(PE)地膜经过不同方法老化后的结构和性能变化不同,本文按固定配方制备了一种PE地膜,研究了该地膜经过不同方法老化后的拉伸性能和结构变化。结果表明,PE地膜在经过4种方法老化40 d后,化学结构的变化相似,只有热氧老化后在1261 cm-1出现C—O特征吸收峰;老化后地膜的熔融温度都有不同程度的下降,且结晶度有明显提高,未老化时的结晶度仅有1.7%,自然老化后结晶度提升最高为13.9%;地膜经过不同方法老化后,拉伸性能都有不同程度的下降,其中热氧光老化速度最快,在20 d时丧失拉伸性能,且横向PE地膜变化比纵向更为敏感;地膜在经过自然暴晒、热氧光老化后数均分子量都有不同程度的上升,重均分子量都有所下降,且热氧光老化后分子量分布明显变窄。

捻度对渔用UHMWPE裂膜纤维线股拉伸性能与耐磨性能的影响研究

为促进超高分子量聚乙烯裂膜纤维(简称UHMWPE裂膜纤维)在渔用绳网中的应用,以膜裂法制备渔用UHMWPE裂膜纤维为原料,通过加捻制备渔用UHMWPE裂膜纤维线股,在此基础上,考察了加捻对UHMWPE裂膜线股的线密度、直径、拉伸性能和耐磨性能的影响。结果显示:UHMWPE裂膜纤维线股随捻度的增加表现出直径逐渐减小、实际线密度先增大后减小以及捻回角逐渐增加等特征;对于不同线密度规格的UHMWPE裂膜纤维线股,随着捻度的增加,其断裂强力均呈现降低的趋势,且纤维线密度越低,加捻对线股断裂强度的影响越小;1600 D的UHMWPE裂膜纤维线股的磨损次数随捻度的增加而降低,而3200和4800 D线股的磨损次数随捻度的增加呈现先降低后升高的变化趋势,且4800 D的不同捻度的线股之间的磨损次数无显著性差异(P<0.05),显示出纤维线密度越大,加捻对其耐磨性能的影响越小。1600、3200和4800 D的UHMWPE裂膜纤维线股的结节强力随捻度的增大呈现先升高后降低的变化趋势,当预加捻度为120 T·m^(-1)时,3种线密度线股的结节强力达到最大值,分别为204.15、373.5、562.41 N,较未加捻UHMWPE裂膜纤维分别提高了50.14%、37.13%和30.22%。在本实验捻度设置范围内,1600 D裂膜线股的结节强度随捻度的增加而增大,较未加捻裂膜纤维结节强度提高了32.49%。研究表明,无捻或低捻度、低线密度UHMWPE裂膜纤维线股可用于UHMWPE裂膜纤维无结网的制备;无捻或低捻度的高线密度UHMWPE裂膜纤维线股则具有较好的耐磨性能;中高捻度、低线密度UHMWPE裂膜纤维线股可用于UHMWPE裂膜纤维有结网的制备。研究结果可为渔用UHMWPE裂膜纤维绳网材料的加工、开发与应用提供参考。

Ballistic Penetration Damage of Hybrid Thermoplastic Composites Reinforced with Kevlar and UHMWPE Fabrics

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.

牵伸倍数对PE-UHMW膜材料性能的影响

高性能纤维增强树脂基复合材料的发展促进了防弹装备的发展,在面对高能杀伤武器威胁加剧和单兵携行负荷增加的情况下,防护装备高防护、轻量化的需求日益迫切,超高分子量聚乙烯(PE-UHMW)膜材料的出现,有助于满足轻质高防的需求。PE-UHMW条带作为PE-UHMW膜材料的最小组成,对膜材料性能的影响决定防弹装备的性能。为探究不同牵伸倍数对膜材料性能的影响,选取由不同牵伸倍数条带制备的膜材料开展理化特性、力学性能和防弹性能研究。测试分析发现,PE-UHMW膜材料在分子量、结晶度、取向度等理化特性的不同使层压得到的复合材料力学性能有所差异,进而在不同弹击条件下防弹性能呈现出差异化特点。由高倍牵伸条带制备的膜材料分子量达到5 658 000 g/mol,由其制备的复合材料具有更加优异的力学性能,弯曲强度为102.12 MPa,弯曲弹性模量为23.30GPa,剪切强度为8.60 MPa,经过层压制备的8 kg/m^(2)面密度靶板在常温条件下防1.1 g标准模拟破片V50值达到了804.50 m/s,51式7.62 mm手枪弹弹着点弹痕高度为13.20 mm。在树脂体系与加工工艺一致的情况下,由高牵伸倍数PE-UHMW条带制备的PE-UHMW膜材料在力学和防弹性能方面具有明显优势,具备在个体防护领域的应用潜力。

催化剂BCE-H 200在高密度聚乙烯装置上的应用

在中韩(武汉)石油化工有限公司Hostalen ACP高密度聚乙烯装置上,采用国产催化剂BCE-H 200分别替代进口催化剂Z 501和Z 509生产了高密度聚乙烯注塑料和薄膜料。分析对比了3种催化剂的活性及粉料粒径分布、堆积密度,并对生产的注塑料和薄膜料进行了表征分析。结果表明:BCE-H 200的活性较Z 501低13.8%,较Z 509高49.2%,其氢调敏感性较Z 501和Z 509低;BCE-H 200生产注塑料和薄膜料时,粉料的粒径分布比进口催化剂Z 501和Z 509更集中,细粉更少,但堆积密度低;采用催化剂BCE-H 200替代催化剂Z 501生产的注塑料刚性较高,韧性较低,相对分子质量分布更宽;采用催化剂BCE-H 200替代催化剂Z 509生产的薄膜料,力学性能变化不大,相对分子质量分布更宽。

Dissolving of Ultra‑high Molecular Weight Polyethylene Assisted Through Supercritical Carbon Dioxide to Enhance the Mechanical Properties of Fibers

The molecular weight of ultra-high molecular weight polyethylene(UHMWPE)fbers is severely decreased compared with raw materials due to high temperature and strong shearing in the dissolving process.In this study,we reported a novel method to assist the dissolving of UHMWPE in parafn oil without severe degradation in order to improve the tensile strength of resultant fbers.UHMWPE fbers with relatively high molecular weight and more excellent disentanglement efect were prepared by gel-spinning with UHMWPE suspension treated with supercritical carbon dioxide(SC-CO_(2)).The dynamic thermomechanical,mechanical and crystalline properties of UHMWPE extracted fbers and drawn fbers were researched comprehensively.UHMWPE extracted fbers obtained after SC-CO_(2) treatment display a higher molecular weight.More importantly,it is clear that the disentanglement of UHMWPE gel fbers gained by processing SC-CO_(2) has been signifcantly promoted compared with that without SC-CO_(2) treatment from dynamic thermomechanical and rheological results,which could also be demonstrated from the cross-sectional morphology of UHMWPE extracted fbers.Furthermore,the tensile strength of UHMWPE fbers prepared through SC-CO_(2) treating is able to attain 30.11 cN/dtex,increased by 10.3%in comparison to UHMWPE fbers gained without assistance of SC-CO_(2).Beyond that,the thermal behavior and crystallization performance of UHMWPE extracted fbers and drawn fbers acquired by way of SC-CO_(2) treatment have also been enhanced.

Effect of bombarding energy on ion beam assisted deposited DLC film on UHMWPE

Diamond-like carbon (DLC) films on ultra-high molecular weight polyethylene substrates were prepared at CHn+ ion bombarding energies of 200-1000eV at room temperature using ion beam assisted deposition technique. The wear tests exhibited a high wear resistance for all DLC films. X-ray photoelectron spectfoscopy and Raman spectroscopy analysis indicated that DLC film was amorphous with a characteristic high fracdion of sp3 bonds in the structure of mixed sp:2+ sp3 bonding at an optimal bombardingenergy of 600eV.

Micro-Macro Scale Relationship in Creep Deformation of Ultra High Molecular Weight Polyethylene

Macroscopic and microscale creep deformations of UHMWPE were investigated by using in situ SAXS.A methodology for the measurement of the local creep deformation of inter-lamellar amorphous phase has been proposed.The local strain of inter-lamellar amorphous phase(£a)and macroscopic strain(£macro)were evaluated and they were compared to study the relati on ship betwee n macroscopic and microscale creep deformation of UHMWPE.Both of them exhibit two deformation regions against creep time.The entanglements show a strong impact on both the macroscopic and local inter-lamellar amorphous phase creep behavior and they can be well correlated to the molecular weight between two entanglements estimated from strain-hardening modulus.Compared to the macroscopic creep deformation,local inter-lamellar amorphous layers have a smaller creep deformation.From the local creep measurement,the apparent modulus of inter-lamellar amorphous phase can also be estimated(200<Ma<500 MPa).These values are much higher than the Young's modulus of bulk amorphous PE,which can be well explained by the confinement of the lamellar stacks and the enhancement of the amorphous phase with the relatively high concentration of entanglements.This study provides a useful means and quantitative data for achieving the scale transition between the micro and the macro structural levels for the study of viscos-elastic deformation.

电子保护膜LDPE专用料流变性能研究

通过不同流变仪对国产电子保护膜低密度聚乙烯(LDPE)专用料的流变性能进行了研究,并与进口电子保护膜LDPE专用料进行了对比。结果表明:2种电子保护膜的流变曲线相近,均具有假塑性流动行为;国产电子保护膜加工时,对温度进行调节,效果比较明显;进口电子保护膜加工时,对剪切速率进行调整,效果比较明显;与进口电子保护膜料相比,国产电子保护膜料的相对分子质量分布略宽,表观黏度低。

超高分子量聚乙烯薄膜制备方法与应用

超高分子量聚乙烯(PE-UHMW)是指分子量在100万以上的聚乙烯材料,其分子结构与高密度聚乙烯(PEHD)类似,是一种综合性能较为优异的工程塑料。PE-UHMW薄膜是一种有机高分子膜,是以PE-UHMW为聚合物基体,进行填料或结构改性并加工至一定厚度的新型功能材料,主要分为无孔薄膜及微孔薄膜2种。因其综合性能优异,具有耐冲击、耐低温、耐腐蚀等性能,被广泛应用于纺织、包装、农业、食品、医疗、锂离子电池隔膜等领域。但由于其分子量较高,分子链间存在大量缠结且熔融状态下流动性不佳等特点,使其难以通过常规方法制备出性能优异的薄膜材料。如今,PE-UHMW的制备及加工工艺得到了较为迅速的发展,本文根据PE-UHMW的结构特点,介绍了近年来PE-UHMW薄膜的研究进展、性能优势、常用制备方法以及主要应用。

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。

VLDPE的结构表征及在拉伸套管膜中的应用研究

对中国石油化工股份有限公司天津分公司(简称天津石化)生产的三元共聚很低密度聚乙烯(VLDPE)和同类进口商品进行对比,通过万能力学测试仪、差热式扫描量热仪、凝胶色谱仪等表征仪器,测试了两种VLDPE的结晶度、热性能、相对分子质量及分布,并分析了拉伸套管膜力学性能。结果表明,天津石化生产的VLDPE结晶度为33.293%,熔融温度为122℃,相对分子质量超过1.4×10^(5),相对分子质量分布值为6.9。以VLDPE制成的薄膜拉伸强度(纵向/横向)为37.5/36.4 MPa,与同类进口商品相当;断裂标称应变(纵向/横向)为857%/931%,高于同类进口商品。

钛合金表面类金刚石碳梯度薄膜的摩擦磨损性能研究

与 Ti6 Al4V合金 /超高分子量聚乙烯摩擦副对比 ,考察了 Ti6 Al4V合金表面类金刚石碳梯度薄膜 /超高分子量聚乙烯摩擦副在干摩擦以及 Hank's溶液和生理盐水润滑下的摩擦磨损性能 .采用扫描电子显微镜观察试样磨损表面形貌 ,并进而分析磨损机理 .结果表明 ,类金刚石碳梯度薄膜具有良好的减摩抗磨性能 ,其体积磨损率约为相同条件下Ti6 Al4V合金体积磨损率的 5 0 % ,相应的超高分子量聚乙烯偶件的磨损率亦较低 .类金刚石碳梯度薄膜的磨损呈现轻微磨粒磨损特征 。