Lamellar crystalline structure of hard elastic HDPE films and its influence on microporous membrane formation

The development of hard elastic high-density polyethylene (HDPE) precursor films and its influence on the microporous membrane formation have been investigated. As a first step, the HDPE precursor films with ‘row-nucleated lamellar crystalline’ structure were prepared by applying elongation stress to the HDPE melt during T-die cast film extrusion and subsequently annealing the extruded films. This unusual crystalline structure was analyzed in terms of lamellar crystalline orientation, long-period lamellar spacing, crystallite size, and degree of crystallinity. The processing (melt extension and annealing temperature)-structure (lamellar crystalline structure)-property (hard elasticity) relationship of HDPE precursor films was also investigated. The uniaxial stretching of hard elastic HDPE precursor films induces the bending of crystalline lamellae, which leads to the formation of micropores between them. The observation of morphology and air permeability for the HDPE microporous membranes have revealed that the well-developed porous structures characterized by superior air permeability were established preferably from the precursor films prepared by the high stress levels and the high annealing temperatures. Finally, the relationship between the hard elasticity of HDPE precursor films and the air permeability of corresponding microporous membranes was discussed.     

相容剂对HDPE/PC共混合金性能的影响

采用熔融接技方法制备HDPE g MAH作为相容剂,研究了接枝单体、引发剂对接枝率和熔体流动速率的影响;并与相容剂EVA对HDPE/PC共混合金体系的增容效果进行了比较。结果表明:HDPE g MAH相容剂的增容效果较好,它的加入使HDPE PC共混合金的综合力学性能得到较大提高。     

硅烷接枝交联HDPE铝塑复合管专用料的研究

以双螺杆挤出机为反应器,考察了影响聚乙烯接枝交联的主要因素,如基础树脂的配比,引发 剂、交联剂的用量及种类,催化剂的用量。通过对这些因素的详细研究,得出了硅烷交联高密度聚乙烯 铝塑复合管专用料的最佳配方。接枝料(质量份数):5000S为55份,7006A为20份,载体树脂为25份, 复配交联剂Ⅰ为2份,抗氧剂2为0 1份,阻聚剂Ⅰ为0 12份,阻聚剂Ⅱ为0 04份。催化料(质量份 数):5000S为85份,载体树脂为15份,催化剂为1份,抗氧剂Ⅰ为0 3份,抗氧剂Ⅱ为0 3份。交联料 (质量份数):接枝料95份,催化料5份。     

Functionalization of high density polyethylene in melt state through ultrasonic initiation and its effect on mechanical properties of glass fiber reinforced composites

Summary Functionalization reaction of high density polyethylene (HDPE) with γ-methacryloxy-propyltrimethoxysilane (MAS) or with MAS and MAH performed in melt state through ultrasonic initiation by a laboratory-scale ultrasonic extruding reactor was studied in this paper. The effect of ultrasonic intensity on the percentage of grafting and melt flow rate of the functionalized products was investigated. The results show that by imposing ultrasonic vibration during melt-extruding process, the scission of HDPE chain bonds can be caused to form macroradicals, the functionalization reaction of HDPE with MAS or with MAS and MAH can be realized. The percentage of grafting and the melt flow rate of the functionalized products depend upon the ultrasonic intensity and reaction temperature. The fuctionalization reaction of HDPE with MAS can be promoted by adding a second grafting monomer MAH. The ultrasonic-induced products have a higher reactivity with the coupling agents coated on the surface of glass fibers, the mechanical properties of the composite improved by the ultrasonic induced product are higher than that of by peroxide initiated product and the mechanical properties of HDPE/GF composite modified by HDPE-g-MAH-MAS are higher than that of by HDPE-g-MAH. The SEM experimental results indicate that an oriented crystal layer exists between the interface of glass fiber and the HDPE matrix, the interfacial bonding strength is the determining factor of the formation of the oriented crystal layer.     

基于人工神经网络的HDPE流变性能预测与研究

针对影响高密度聚乙烯(HDPE)流变性能各因素之间的非线性关系建立了一个优化后的BP网络,然后通过实验取得样本数据,进而对网络进行训练,用训练合格后的人工神经网络对高密度聚乙烯在不同温度或不同剪切速率下的剪切应力进行预测,并绘制出预测的流动、流变曲线,最后对预测和实际测得的流动、流变曲线进行了比较分析。     

高密度聚乙烯5000S耐老化性能的研究

通过考察不同抗氧剂体系对牌号为5000S的HDPE熔体流动速率、力学性能、氧化诱导期的影响，研究加工工艺条件对HDPE5000S的白度等指标的影响，优化了助剂配方，确定了加工工艺条件，从而提高了HDPE5000S产品的外观质量和单丝制品的物性。     

Effect of CNT-coated carbon fibres in HDPE composites

The mechanical properties of thermoplastic HDPE composites filled with CF and CNT were studied. Coupling agent surface-treated CF-filled HDPE composites increased their tensile strength and impact strength, which is further increased with the addition of CNT. Coupling agent was proved to play an important role in the improvement of the interfacial adhesion of the CF/HDPE composite. SEM showed that CNT coating-treated CF/HDPE composites show better dispersion of the ?ller into the matrix.     

新型HDPE管在天津海河北安道工程中的应用

以新型高密度聚乙烯(HDPE)塑料管在天津市海河综合开发改造项目北安道工程中的实际应用,阐述了此种管道的施工方法、施工过程中的质量控制及推广应用此种管材的前景。     

宽扎河引水工程HDPE管道设计施工技术

结合工程实际,介绍了宽扎河引水工程HDPE管道设计及施工流程,实践证明该技术从设计到施工是切实可行的,并且指出,宽扎河引水工程的成功,为机场正式工程施工提供了先决条件,也为机场增建管道提供了可靠的技术数据。     

虹吸式雨水排放系统在某大型工业厂房的运用

在分析和比较传统屋面雨水重力排放方式和虹吸雨水排放方式的原理和特点的基础上,针对某大型工业厂房的建筑特点和功能要求,对其屋面的雨水排放系统进行了选择,并对虹吸式雨水排放系统的优缺点和在实际工程中的运用方法进行了总结。