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.

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.

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.

等离子体改性超高分子量聚乙烯增强环氧树脂自润滑性能研究

通过等离子体处理在超高分子量聚乙烯(UPE)表面接枝极性基团,增强其与环氧树脂(EP)基体的界面粘附力,改性UPE的加入增强了环氧树脂EP的自润滑性能。结果表明:添加质量分数4%的改性UPE,使EP复合材料的摩擦系数和比磨损率降低至0.016和0.98×10^(-5)mm^(3)/(N·m),相比于纯EP,分别降低了96.3%和91.1%。

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。

影响UHMWPE原料溶胀性能因素的初步探讨

通过单因素条件对超高分子质量聚乙烯树脂与白油混合液溶胀行为进行了研究,探讨了不同溶胀时间、溶胀温度、质量分数,以及超声波处理时间等对其溶胀性能的影响。并通过其混合液黏度、溶胀度的测试,得出国内外四种不同供应厂家、分子质量在400万左右的超高分子质量聚乙烯原料在不同溶胀工艺条件下的影响结果,为车间溶胀工艺提供一定的理论参考。

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.

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.

超高相对分子质量聚乙烯纤维表面改性及聚氨酯树脂涂覆性能研究

先采用化学试剂处理法对超高相对分子质量聚乙烯(UHMWPE)纤维进行表面改性处理,再利用合成的聚氨酯树脂涂覆UHMWPE纤维以形成纤维保护层。研究发现:经60℃、2 min的K_(2)Cr_(2)O_(7)/H_(2)O/H_(2)SO_(4)混合液改性处理后,纤维表面产生了大量的极性官能团,这有利于提高树脂-纤维界面结合力,且单丝最大拉伸载荷达47.96 N;利用最优质量配比制得的聚氨酯树脂涂覆表面改性的UHMWPE纤维,聚氨酯树脂与纤维黏结良好,且聚氨酯树脂涂层能显著提升UHMWPE纤维的耐磨性能。

超高分子量聚乙烯纤维复合材料的研究进展

概述超高分子量聚乙烯(UHMWPE)纤维增强复合材料的研究进展,详细介绍了UHMWPE纤维的各种优良特性和UHMWPE纤维增强复合材料用基体树脂,以及UHMWPE纤维增强复合材料的制备方法与工艺,对UHMWPE增强复合材料的应用及其应用领域进行了汇总。

聚乙烯管材专用树脂的性能

以专用Z-CAT和通用T-CAT为催化剂,采用淤浆法聚乙烯CX工艺制备了专用树脂Z-4902T和通用树脂T-4902T,利用GC,^(13)C NMR,GPC,DSC等方法分析了催化剂聚合过程中气相组分的含量、树脂产品的共聚单体含量、树脂分子量及其分布,考察了两种树脂的力学性能和流变性能。实验结果表明,催化剂Z-CAT可明显减少乙烯乙烷化反应的发生,第一聚合反应釜乙烷含量从11.65%(φ)降到4.10%(φ),第二聚合反应釜乙烷含量从1.85%(φ)降到0.79%(φ)。在相同负荷、相同共聚单体加入量下,Z-4902T树脂共聚单体含量较高,密度下降明显,具有更好的熔体强度和加工性能,在低温(-20℃)下Z-4902T树脂简支梁缺口冲击强度性能更优,为14.7 kJ/m^(2),具有更好的韧性。

双峰PE树脂的结构与性能

研究了国产催化剂和进口催化剂分别生产的同一牌号双峰聚乙烯树脂的结晶性能和流变行为.表征了其相对分子质量及其分布。2种树脂的力学性能差异可归结为其相对分子质量及其分布和结晶性能的不同;国产催化剂生产的树脂要达到同进口催化剂生产的树脂一样的流变行为,模头温度必须达到200℃以上。

TQ硅树脂包覆红磷的制备及其在UHMWPE中的应用

为了克服红磷阻燃剂自身的缺点,采用溶胶-凝胶法制备了TQ硅树脂包覆红磷。测试了样品的吸湿性、抗氧化性及热稳定性,并研究了其对超高分子量聚乙烯(UHMWPE)阻燃性能和力学性能的影响。结果表明:红磷经过包覆后,吸湿性、抗氧化性和热稳定性得到了很大的改善,将所制包覆红磷应用于UHMWPE中,阻燃和力学性能都比使用未包覆红磷阻燃剂有所提高。

UHMWPE树脂及其纤维应用现状和发展前景

综述了超高相对分子质量聚乙烯(UHMWPE)树脂及其纤维的应用现状和发展前景。表明UHMWPE主要以树脂和纤维两种形式应用于耐磨自润滑材料、过滤材料、耐低温和化学腐蚀材料、极低介电常数电子通讯材料、高性能弹道材料、防爆材料、体育竞赛器材、高性能绳索等广泛用途。指出加强改性研究和加快建立行业标准对我国UHMWPE关联产业和市场的发展具有重要意义。

毛竹尺寸稳定性处理的研究

采用聚乙二醇处理、低分子量酚醛树脂处理、乙酰化三种处理方法对毛竹尺寸稳定性进行改进处理,研究结果表明,三种处理方法中乙酰化后竹材在密度、含水率、抗缩率上均具有良好表现,其尺寸稳定性的效果最为明显,所引起的密度增加最小。

复合材料用高性能纤维及热塑性树脂发展现状

介绍了芳纶、碳纤维和超高相对分子质量聚乙烯等3种纤维的基本性能、国内外生产及应用情况,还介绍了聚酰胺、聚醚醚酮、聚苯硫醚及聚酰亚胺等4种热塑性树脂的性能及在研发和生产方面与国外的差距,由此提出了加强研究机构与企业充分合作、国产材料应用及原材料质量控制的建议,并对今后热塑性复合材料的发展进行了展望。

UHMWPE／Epoxy冻胶体系的流变行为研究

研究了环氧树脂(Epoxy)加入后对超高分子质量聚乙烯(UHMWPE)稳态表观粘度、粘流活化能以及复数模量和粘度的影响。结果表明,环氧树脂添加量低于1ω,UHMWPE／Epoxy冻胶体系的表观粘度和粘流活化能都低于空白 UHMWPE冻胶体系;当环氧树脂添加量增加至3 ω以后,冻胶体系的表观粘度和粘流活化能均比空白UHMWPE冻胶体系高。