Effect of Heptadecane on Sorption of 2,6-di-Tert-butyl-4-Methylphenol by Polyethylene

Abstract

The sorption of vapors of 2,6-di-tert-butyl-4-methylphenol (DTP) by HDPE containing different concentrations of heptadecane has been studied using the ultraviolet spectrometry method. The isotherms of DTPh sorption at 100–200°C are presented by the Langmuir equation. The concentration of sorption of DTPh has no dependence on temperature, but depends on the concentration of heptadecane in a polymer. The heats of dissolution of DTPh in polyethylene have been determined.     

The Depth of Penetration of Radiation Oxidation in the Presence of Stabilizers

Abstract

The disposable syringes manufactured from low pressure polyethylene (LPPE) and polypropylene (PP) are widely used in the USSR. Irradiation by ionizing radiation is one of the most prospective methods of sterilizing the disposable syringes. Problems in developing the polyethylene and polypropylene formulations that remain stable under the action of sterilizing doses of radiation and subsequent prolong storing are reviewed.     

Electrical Properties of 10 MeV Electron Beam Irradiated and Aged Low Density Polyethylene

Polymers play a very important role in electrical systems as insulation materials. The microscopic failures occurring in the polymer under working conditions will be important in its required characteristics. In this work we focused on the effects of accelerated aging on the electrical properties of low density polyethylene (LDPE) and crosslinked polyethylene (XLDPE). The samples of LDPE were prepared in sheet form with the thickness of 0.6 ± 0.1 mm and were irradiated under the 10 MeV electron beam of a Rhodotron accelerator at the dose range of 70 to 370 kGy. Then, the samples were stored in an oven at temperature 75°C for 3, 6, 10 and 13 days. Electrical properties such as the breakdown voltage and resistance of the aged samples were measured and compared. Increasing the aging time for unirradiated samples has a serious and moderate influence on their surface resistivity and breakdown voltage, respectively. The results indicated a maximum value for the surface resistance at the optimum radiation absorbed dose, which is approximately 220 kGy for all the samples.     

聚乙烯保温管现场防腐补口施工控制

保温管现场补口的质量是决定管道使用寿命的关键因素,因此,加强保温管现场补口过程的质量控制和成品检验,对于延长保温管寿命极其重要。本文从聚乙烯保温管补口的现场实际情况出发,介绍了补口施工流程和施工质量控制点等方面的问题。     

聚乙烯燃气管道系统的可靠性研究

分析了聚乙烯燃气管道系统可靠性的特点,从聚乙烯原料、管材、连接、运行等方面论述了提高可靠性的方法。介绍了一些新标准,指出制定先进的技术标准并要求相关方严格遵守,是提高聚乙烯管道系统可靠性的有效途径。     

加工温度对低密度聚乙烯薄膜热收缩性能的影响

考察了熔体温度及热收缩温度对低密度聚乙烯（牌号为1810 D）薄膜热收缩性能的影响。结果表明,熔体温度对薄膜横向热收缩率的影响较纵向大;在吹膜过程中,适宜的熔体温度为200～230℃;适当提高熔体温度或热收缩温度,有利于提高薄膜的热收缩性能,减小薄膜纵横向热收缩差异。     

聚乙烯催化剂PGE-100的催化性能研究

研制出-种聚乙烯（PE）催化剂PGE-100,分别在淤浆聚合及气相聚合条件下,对该催化剂的聚合动力学进行了研究,并考察了聚合温度、聚合时间对聚合活性的影响,评价了该催化剂的氢调敏感性、乙烯／1-丁烯共聚性能及其稳定性。结果表明,PGE-100的聚合动力学表现为快速引发、快速衰减型,聚合活性主要集中于反应前期;在淤浆聚合条件下,聚合活性随聚合时间的延长而增大,随着聚合温度的升高,聚合活性先增大后减小,在85℃时达到最高值;PGE-100的氢调性及乙烯／1-丁烯共聚性能优良且稳定,不同批次催化剂的性能重复性良好。     

端叠氮基聚乙二醇的合成与表征

以端羟基聚乙二醇(PEG)为反应底物,甲苯为溶剂,在80℃下用二氯亚砜对端羟基氯代;再在N,N-二甲基甲酰胺中,与叠氮化钠进行叠氮化反应得到端叠氮基聚乙二醇(N3PEG).用FT-IR、1H NMR、13C NMR、DSC等对产物进行了表征.结果表明,聚乙二醇端羟基峰消失,同时出现明显的叠氮基特征峰;聚乙二醇端羟基活泼...     

聚乙烯反应器的设计与制造

以设计实例阐述气相法制聚乙烯工艺装置中核心设备聚乙烯反应器的工艺技术、壳体及内件(圆环导流器、分布板)的结构特点、设备材料的选择及特殊要求、制造过程中的关键控制点和热处理方法的比较,为以后同类设备的设计和制造提供参考。     

催化氧化法制备硬质氧化蜡

实验制备的氧化蜡具有与天然巴西棕榈蜡相近的性能。考察了反应温度、反应时间、空气流速、蜡的选择和用量、催化剂用量等因素对氧化蜡质量的影响。结果表明,最佳工艺条件为:反应温度150～160℃,激发温度180～185℃,反应时间6～8 h,空气流速0.4 m3/h,石蜡用量65.0%,聚乙烯蜡用量20.0%,硬脂酸用量10.0%,氢氧化钙用量2.5%～3.0%,催化剂用量0.02%～0.05%,DTBP用量0.6%～1.0%。得到的产品具有较高的酸值、皂化值和较佳的针入度值。