初生态超高分子量聚乙烯凝聚态研究

研究了超高分子量聚乙烯（UHPE）的凝聚态,采用DSC研究UHPE熔体等温结晶后的熔融行为;利用傅立叶变换红外光谱（FTIR）研究初生态UHPE链构象,通过偏光显微镜（POM）研究UHPE熔体的光学性质,实验结果表明,初生态UHPE的大分子凝聚态是一种独特的无相互贯穿的多链凝聚态,熔融时,初生态UHPE的凝聚态转化为向列型结构,在熔体结晶时,向列型结构转化为伸直链晶体,再熔融时,熔点的降低是源于伸直链束中晶区链长度的降低。这种特殊凝聚态结构,赋予熔融后初生态结构可恢复的特性,当UHPE熔体在120－130℃下长时间等温结晶后,伸直链束中晶区逐渐增厚,并恢复至初生态的结构,此外,还利用红外差减谱法对链构象进行分析,实验结果支持该凝聚态结构模型。     

超高分子量聚乙烯凝胶结晶膜的结晶形态X射线衍射研究

对由准稀溶液速冷凝胶化结晶方法制备的超高分子量聚乙烯(UHMWPE)膜,应用广角及小角X射线衍射进行了研究,证明所形成的膜是片晶-分子链折叠的层积状结构。片晶折叠链的分子链方向(即C轴方向)垂直于膜面,在片晶间无规排列的分子链平行膜面,具有较强的“排列”取向,片晶-无规排列链形成的大点阵间距为109(?),片晶间的无规排列链沿垂直分子链方向的统计平均间距约为4.6(?),分子链数约为4～5。这一结果在超拉伸过程中,有利于从片晶-折叠分子链到完全伸直链的转变,从而可获得超高拉伸比(λ>200)。     

超高分子量聚乙烯挤塑技术

结合生产、工程实践详细介绍了超高分子量聚乙烯管材超强的性能、优越的性价比和广泛的使用前景;介绍了新型材料——超高分子量聚乙烯工业应用现状以及在管道生产技术和工艺方面的研究、探索和创新,为相关工程技术人员提供了一定的学习研究契机。     

基于粘弹性的超高分子量聚乙烯齿轮有限元分析

以超高分子量聚乙烯的非线性粘弹性性质为基础，将代表非线性、大变形的超弹性Arruda-Boyc。模型与粘弹性力学模型相结合，建立了超高分子量聚乙烯齿轮的力学模型和几何模型，并将其与ABAQUS非线性有限元分析软件相结合，对齿轮的应力分布、变形、承载能力进行分析。结果显示，齿根部位所受的弯曲应力最大，建立在粘弹性基础上的分析结果具有较高的可靠性。     

超高分子量聚乙烯隔板微观结构的研究

对聚乙烯（ＰＥ）隔板的微孔形态进行了研究,利用压汞法对隔板的微观结构参数进行测定,与进口样品的测试结果进行了比较。研究了不同的原料、工艺参数等对隔板加工性能及使用性能的影响,分析了不同原料、不同组分所形成的最终微观结构的差异,在此基础上确定了原料体系选择原则。     

超高分子量聚乙烯聚合材料的磨擦磨损性能

用MPV－200型磨擦磨损试验机和腐蚀磨损试验机,对MoS2、PTFE、石墨、玻璃纤维、碳纤维填充的超高分子量聚乙烯（UHMW－PE）塑料复合材料的磨擦磨损性能进行了较为系统的研究,结果表明：填充MoS2、PTFE、石墨可降低UHMW－PE的磨擦系数;而添加玻璃纤维则增大了UHMW－PE的磨擦系数;添加碳纤维对UHMW－PE的磨擦系数几乎无影响。同时,添加填料可使用UHMW－PE的耐磨性显著提高,其中石墨的减磨降磨效果最佳。重点研究了载荷、滑动速度对高分子量聚乙烯基体＋20％石墨复合材料的磨擦磨损性能的影响。     

基于粘弹性超高分子量聚乙烯齿轮有限元分析

以超高分子量聚乙烯的非线性粘弹性性质为基础,将代表非线性、大变形的超弹性 Arruda-Boyce 模型与粘弹性力学模型相结合,建立了超高分子量聚乙烯齿轮的力学模型和几何模型,并将其与 ABAQUS 非线性有限元分析软件相结合,对齿轮的应力分布、变形、承载能力进行分析。结果显示,齿根部位所受的弯曲应力最大,建立在粘弹性基础上的分析结果具有较高的可靠性。     

低密度聚乙烯结晶与熔化行为研究

作者用DSC法研究了LDPE的等温和非等温结晶动力学和熔化行为。LDPE的平衡熔点和晶片折迭表面自由能分别为111.7℃和1.33×10~(-11)J/m~2,有8％的长支链参与主链结晶。     

Isothermal Crystallization Kinetics of Microencapsulated Polyethylene Glycol Particles

The microenapsulated polyethylene glycol （PEG） with different molecular weight by a fluidized coating method has been prepared and the crystallization behaviors of PEG particles in three-dimensional confined vohume were investigated by using differential scanning calorimetry （DSC） measurement. The results showed that the width of the crystallization peak of PEG increases and its height gradually diminishes in case that the PEG particles are microencapsulated. Compared with the non-microencapsulated PEG particles, the proportion of the first crystallization peak of microencapsulated PEG particle increases, and that of the second one decreases. The reason for the difference maybe is that the crystallization process of microencapsulated PEG particles is uniform and the crystallization ends when the spherulites touch the wall, thus the opportunity of producing the second crystallization peak was relatively reduced.     

聚醚粘合剂体系的结晶特性

用热台偏光显微镜和电子显微镜研究了ＰＥＧ共聚物粘合体系在不同温度下的形态结构变化．比较网络结构表明，形态结构与ＰＥＧ相对分子质量有关，随ＰＥＧ相对分子质量增大，结晶倾向性增加．     

Study on the Characteristics of Macromolecular Chains of Cellulose in Dilute Solutions

The characteristics of macromolecular chains of cellulose in dilute solutions are discussed. Viscometry was used for the measurement of the intrinsic viscosity [η] of four cellulose samples, which were respectively dissolved in the solvent Tri-ethylenediamine cadmium hydroxide Cadoxen (Cadoxen), Cupriethylenediamine hydroxide(Cuen), iron sodium tartrate complex(EWNN) and N,N-dimethylacetamide(DMAc)with lithium chloride(LiCI, 9% w/w). The intrinsic viscosity of the four solutions decreased in the following manner:[η]DMAc/LiCl>[η]EWNN>[η]Cuen>[η]Cadoxen. The stability of cellulose (Sample α-cellulose) dissolved in solvents Cuen and EWNN was tested by plotting the intrinsic viscosity vs. time. The values of Huggins constant K_H for the cellulose samples dissolved in solvents Cadoxen,Cuen,EWNN and DMAc/LiCl (9% w/w ) were calculated.     

Manufacturing of Ultra - high Molecular Weight Polyethylene Fiber Rein-forced 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.     

稀溶液汽液平衡的气相色谱测定模型研究

通过较严格的数学处理,导得了气相色谱法测定稀溶液汽液平衡的基本方程,证明了现有两个模型只是本模型的特例,将最近提出的稀溶液活度系数模型引入基本方程中,得到了简单易用的工作方程,克服了原同类方程难以处理的困难;计算结果表明,浓度越高,本文模型的修正越重要。最后,还导得色谱柱内气相流速的较严格的计算公式。     

热处理对聚丙烯结晶形态的影响

用偏光显微镜研究了热处理对聚丙烯的结晶形态的影响。结果表明,缓冷等温结晶时PP球晶尺寸大,大小不均匀,但形态清晰,结晶度高,而在快冷非等温结晶条件下的PP球晶细化且较均匀,但形态模糊,结晶度降低,结晶不完善。     

Gradient Changing Morphology Research of Cross-linked Polyethylene Thick Insulation of 110 kV Power Cable

The thick insulation layer of 110 kV XLPE power cables will result in the gradient changing morphology with the radius due to crosslinking process and cooling of the XLPE insulation. In this paper, the morphology of cross-linked polyethylene （XLPE） insulation of 110 kV cable and the uniforming effect of the heating process on it are researched by the differential scanning calorimetry （DSC） and X-ray diffraction （WAXD）. The middle layer morphology structures of insulation produced by normal technology are of better uniform, while the crystallinity of the inner and outer layer of the insulation is lower than that of the middle one. The melting enthalpy AHm of materials displays the difference of the crystal morphologies sensitively. The difference of crystallizing morphology in different layers of the high-voltage power cable insulation can be improved by heating process. But the uniforming of morphology of the insulation by heating process requires sufficient ttanperature and time. The effect of the on-line stress-relaxation equipment used widely by cable works now should be doubted. The test results of WAXD reveal that thermal stress changes the interplanar distances in the crystal region. So the radical stress in the insulation is tensile mainly.