超高分子量聚乙烯的辐照效应

通过密度测定和ＤＳＣ热分析，观测了超高分子量聚乙烯的辐射效应。实验结果表明：在吸收剂量０—１．１３ＭＧｙ范围内，密度随吸收剂量的增加而增大，熔化热和熔点也有所增加，特别是在低剂量范围内增加十分明显。以上结果都说明，超高分子量聚乙烯在辐照过程中，结晶在完善或有新的结晶形成     

仿生矿化的研究Ⅰ．文石型碳酸钙的合成

在聚乙二醇（ＰＥＯ）存在下，ＣａＣｌ２和Ｎａ２ＣＯ３反应生成了类似红鲍鱼壳的含有ＰＥＯ的碳酸钙──高聚物复合材料。Ｘ－衍射和电镜照片显示，它有两种微观结构：外层为文石型和方解石型结构，内层为针状文石型结构。热重分析表明，该材料中含有３％左右ＰＥＯ。结果说明，聚合物对碳酸钙晶核的形成和晶体的生长有很大影响，并对其形成机理进行了初步探讨。     

PEG20000中试放大的工艺研究

在一定温度和催化剂作用下 ,分别利用本体聚合和溶剂聚合的方法 ,在 1L、10 0L不锈钢高压反应釜中合成了相对分子质量为 2 0 0 0 0的聚乙二醇 ,并讨论了聚合反应机理 ,研究了催化剂用量、反应温度、反应时间对聚合反应的影响。经过红外、核磁共振、凝胶色谱、化学分析等方法对产物进行了表征。     

Immobilization and activation of vanadium(III) and titanium(III) single‐site catalysts for ethylene polymerization using MgCl2‐based supports

Significant increases in the activity of vanadium(III) amidinate catalysts for ethylene polymerization have been obtained by immobilization on a MgCl₂‐based support prepared by reaction of AlEt₃ with a MgCl₂/ethanol adduct. Catalyst immobilization and activation on this type of support prevents the rapid decay in activity observed under homogeneous polymerization conditions with unsupported catalysts. Stable polymerization activity is also observed with analogous titanium(III) complexes. Polyethylene with narrow molecular weight distribution and spherical particle morphology is obtained without reactor fouling. Copyright © 2005 Society of Chemical Industry     

Low density polyethylene and grafted lignin polyblends using epoxy‐functionalized compatibilizer: mechanical and thermal properties

Lignin was graft copolymerized with methyl methacrylate using manganic pyrophosphate as initiator. This modified lignin was then blended (up to 50 wt%) with low density polyethylene (LDPE) using a small quantity of poly[ethylene‐co‐(glycidyl methacrylate)] (PEGMA) compatibilizer. The mechanical properties of the blend were substantially improved by using modified lignin in contrast to untreated lignin. Differential scanning calorimetry studies showed loss of crystallinity of the LDPE phase owing to the interaction between the blend components. Thermogravimetric analysis showed higher thermal stability of modified lignin in the domain of blend processing. This suggested that there is scope for useful utilization of lignin, which could also lead to the development of eco‐friendly products. Copyright © 2005 Society of Chemical Industry     

聚乙烯丙纶复合防水卷材的特点及其应用

介绍了聚乙烯丙纶复合防水卷材的产品结构特点和性能特点、防水系统结构特点和配套材料、应用拼接技术以及产品应用范围。     

茂金属催化剂气相法聚乙烯中试研究

我国自行开发的茂金属催化剂在气相法聚乙烯中试装置上进行了运行试验和性能试验。考察了茂金属催化剂ＡＰＥ－１的运行稳定性和适应性以及聚合反应条件与催化剂活性、产品熔融流动性能和产品密度的关联性。经过测定，试验所得产品的相对分子质量分布特性与国外同类产品相近。     

Liquid viscosities and densities of HFC-134a+glycol mixtures

Liquid viscosity and density of six binary mixtures of HFC-134a with glycols [ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol (400), and polypropylene glycol (2000)] have been measured in the temperature range from 273 to 333 K. The viscosity was measured by a rolling-ball viscometer calibrated with standard liquids of viscosities and densities (JS5, JS10, JS20, and JS50). The density was measured with a glass pycnometer. The uncertainties of the measurements were estimated to be less than 3.4 % for viscosity and 0.04 % for density, respectively. An equation is given to represent the obtained viscosity values as a function of weight fraction and temperature.     

高发泡聚乙烯阻燃初探

根据聚合物燃烧现象和一般阻燃机理寻求研究高发泡聚乙烯的阻燃方法和阻燃剂。研究结果表明:只有对添加型阻燃剂三元并用,方能不降低高发泡聚乙烯的物性,制得较为理想的高发泡聚乙烯自熄型制品。     

α-戊(己)基肉桂醛的合成

采用聚乙二醇 ( PEG 2 0 0 )作相转移催化剂 ,用氢氧化钾醇水溶液代替氢氧化钾醇溶液合成了 α 戊 (己 )基肉桂醛 ,收率提高到 85%以上。用此工艺合成的产品纯度高 ,香气好 ,具有较高的工业实用价值。