超高分子量聚乙烯纤维的低温等离子处理

研究了超高分子量聚乙烯纤维的低温等离子表面处理。经低温等离子处理,超高分子量聚乙烯纤维对乙二醇的浸润性提高,接触角降低,纤维表面产生了活性自由基,纤维对亚甲基蓝的吸附性增强。等离子处理使纤维含氧量增加,表面产生沟槽,比表面积增大,纤维/环氧复合材料的层间剪切强度提高3倍以上。     

UHMWPE基水润滑轴承摩擦及润滑特性的试验研究

针对纤维填料改性UHMWPE水润滑轴承的摩擦磨损性能进行研究。在平面摩擦磨损试验机上对玻璃纤维及碳纤维填料对UHMWPE复合材料摩擦性能进行试验,并分析GF-CF-UHMWPE材料与Thordon SXL材料在干摩擦、水润滑工况下的摩擦因数及磨损量。最后,采用径向水润滑轴承试验台对比研究了GF-CF-UHMWPE轴承和Thordon SXL轴承在不同载荷下摩擦因数随转速的变化规律。结果表明:纤维填料能显著增强UHMWPE的减摩性和耐磨性,GF-CF-UHMWPE材料具有更好的耐温性能,线性热膨胀系数也显著减小;GF-CF-UHMWPE轴承具有相同载荷下启动转速低,启动摩擦因数小的特性。     

Numerical and experimental investigations into ballistic performance of hybrid fabric panels

Strong, low density fibres have been favoured materials for ballistic protection, but the choice of fibres is limited for making body armour that is both protective and lightweight. In addition to developments of improved fibres, alternative approaches are required for creating more protective and lighter body armour. This paper reports on a study on hybrid fabric panels for ballistic protection. The Finite Element (FE) method was used to predict the response of different layers of fabric in a twelve-layer fabric model upon impact. It was found that the front layers of fabric are more likely to be broken in shear, and the rear layers of fabric tend to fail in tension. This suggested that using shear resistant materials for the front layer and tensile resistant materials for the rear layer may improve the ballistic performance of fabric panels. Two types of structure, ultra-high-molecular-weight polyethylene (UHMWPE) woven and unidirectional (UD) materials, were analyzed for their failure mode and response upon ballistic impact by using both FE and experimental methods. It was found that woven structures exhibit better shear resistance and UD structures gives better tensile resistance and wider transverse deflection upon ballistic impact. Two types of hybrid ballistic panels were designed from the fabrics. The experimental results showed that placing woven fabrics close to the impact face and UD material as the rear layers led to better ballistic performance than the panel constructed in the reverse sequence. It has also been found that the optimum ratio of woven to UD materials in the hybrid ballistic panel was 1:3. The improvement in ballistic protection of the hybrid fabric panels allows less material to be used, leading to lighter weight body armour.     

UHMWPE纤维纬编针织复合材料的制备工艺研究

以超高分子量聚乙烯(UHMWPE)纤维为原料,实现其在电脑横机上的编织,将6层纬平针织物、6层罗纹织物以及6层畦编织物分别通过真空辅助树脂传递模塑成型技术(VARTM)复合成复合材料板。VARTM工艺的最大优点是模具简单、成本低、模具抽真空形成负压使纤维与树脂分布更均匀。综合考虑UHMWPE纤维特点及VARTM工艺的工艺条件,实验用树脂为粘度低、浸润性好的环氧树脂;为使制备的复合材料均衡对称,采用(0°,90°)3s铺层方式;成功制备出了比较理想的纬平针、罗纹和畦编UHMWPE纤维纬编针织增强复合材料,为后续UHMWPE纤维纬编针织复合材料力学性能的研究及其拓展领域的应用奠定了一定的理论和实验基础。     

超高分子量聚乙烯在人工髋关节中的摩擦磨损研究

超高分子量聚乙烯(Ultra-high molecular weight polyethylene,UHMWPE)的磨损是导致人工髋关节失效的重要原因之一。介绍了UHMWPE体外摩擦的磨损机理和改性方法,阐述了一些研究摩擦磨损的试验手段,如髋关节模拟机的研究、润滑体系、磨损的测定、磨屑的评价、有限元分析等,提出了UHMWPE在目前临床应用上亟待解决的问题。     

两类高岭土填充UHMWPE基复合材料及其摩擦磨损特性

分别用釜内聚合和机械熔融混合方法制备高岭土填充UHMWPE基复合材料,对其热性能,结晶性、聚集态结构和与45钢对摩的滑动摩擦磨损性能进行了实验研究,并分析了复合材料的摩擦磨损特性与其结构之间的联系。结果表明,釜内聚合法制备的复合材料具有比较好的性能,良好的性能源于高度分散的高岭土颗粒的增强作用和较高的界面结合强度,也与UHMWPE的结晶形态有关。     

玻璃微珠/UHMWPE复合料的制备及性能

用原位聚合法制备了玻璃微珠／超高摩尔质量聚乙烯(UHMWPE)复合料，并进行了性能测定。结果表明：该复合料不但基本保持了超高摩尔质量聚乙烯原有的优异性能，而且该复合料的硬度、热变形温度等都有不同程度的提高。     

钛合金基类金刚石梯度薄膜的生物摩擦学性能评价

通过与钛合金／超高分子量聚乙烯摩擦副的对比，研究了DLC／UHMWPE摩擦副分别在干摩擦、生理盐水^L和Hank's溶液润滑下的摩擦磨损特性。用二次离子质谱和声波反射划痕仪分别测定了DLC梯度薄膜的组分分布和附着强度，并用扫描电子显微镜观察试样表面形貌，探讨其磨损机理。结果表明：用PSII-IBED法制备的DLC薄膜的组分由内向外呈梯度变化，膜的附着强度较高。DLC梯度薄膜是一种减摩耐磨材料，其摩擦系数随载荷的增大而减小。     

Toughening high performance ultrahigh molecular weight polyethylene using multiwalled carbon nanotubes

We report experimental observations on the drastically enhanced toughness in the high-strength and high-modulus ultrahigh molecular weight polyethylene (UHMWPE) films due to the addition of 1 wt% multiwalled carbon nanotubes (MWCNTs). A combination of tensile and Raman spectroscopic measurements showed that the presence of MWCNTs in the composites can lead to a ∼150% increase in strain energy density in comparison with the pure UHMWPE film at similar draw ratios. This is accompanied with an increase of ∼140% in ductility and up to 25% in tensile strength. We attribute the above observations to the chain mobility enhancement in UHMWPE induced by the MWCNTs.     

高强有机合成纤维的结构形成

 对典型刚性结构的对位芳酰胺纤维和柔性结构的超高分子量聚乙烯纤维的结构特征及其形成过程进行分析,特别是纺丝及热处理工艺对纤维结构变化的影响,认为有机合成纤维高强化,应使纤维在结构上满足以下2个特征：高取向度和高结晶度;聚合物分子链能够充分伸展形成伸直链结晶。同时,介绍了PPTA纤维和UHMWPE纤维的目前进展情况。提出能够形成高取向、高结晶度且分子链充分伸直结构的聚合物,可以通过控制纺丝和热处理工艺制造出高强纤维。