Unipol工艺聚乙烯Ziegler-Natta催化剂研究及应用进展

综述了8种适用于Unipol工艺气相聚乙烯Ziegler-Natta催化剂的制备路线,分析了各催化剂的优缺点:M催化剂应用范围广,但活性低;BCG-Ⅳ催化剂制备中加入促进剂,初始活性和总活性都高;SCG-1催化剂制备工艺简单,活性适中;GM催化剂在载体活化过程中引入了特殊结构的给电子体,催化剂活性高、聚合物堆积密度也高;J催化剂性能优异,是Unipol工艺催化剂的发展方向;BCS-02催化剂较适合冷凝态操作;BCS-01催化剂制备工艺独特,但制备条件要求高;SLC-S催化剂不以硅胶作为载体,在保证催化剂高效率的同时,成本大大降低。对我国Unipol工艺Ziegler-Natta催化剂的研究及国产化提出了建议。     

尤尼帕聚乙烯工艺的进展

尤尼帕技术是美国联合碳化物公司开发的气相流化床生产 HDPE/LLDPE 的工艺。世界上采用尤尼帕的生产能力已达6Mt/a 以上。用该技术生产出来的 PE 树脂,产品牌号广,已用于日常消费及工业的最终用途上。本文综述了尤尼帕技术的发展历史、工艺上的优点,以及近年来所取得的进步,包括减少反应器内片状物的生成,反应器入口导流器和卸料系统的改进等等。     

国外气相法PE工艺进展

介绍国外近几年来在气相法（流化床）ＰＥ工艺技术方面的主要进展,并针对国内的ＰＥ生产技术及科研状况提出设想。     

HYPOL工艺的改进和发展

介绍了ＨＹＰＯＬ工艺的改进和发展,主要表现在采用三釜流程、增加粉末洗涤塔、使用间接冷却水对温度进行探讨等,这些改进使ＨＹＰＯＬ工艺流程缩短、投资减少、操作简单且安全可靠。     

拉丝工艺调整优化

介绍了编织袋生产线关键工序拉丝的生产工艺,以及对影响最终产品质量的各工艺参数、原料配方进行调整优化过程,既降低了成本,又使产品内在质量和外观质量都得到提高。     

塑料扁丝生产过程中冷却工艺条件的探讨

根据热传递原理,建立了水浴式冷却挤出平膜的数学模型,并据此讨论了扁丝生产过程中聚丙烯（ＰＰ）和高密度聚乙烯（ＨＤＰＥ）对冷却水温度和冷却水流速的要求,在给定条件下确定了其合理的工艺参数。     

聚乙烯气相流化床生产技术进展

介绍了近几年聚乙烯气相工艺四个主要进展，即ＵｎｉｐｏｌⅡ工艺、冷凝态操作技术、Ｓｐｈｅｒｉｌｅｎｅ工艺和茂金属催化剂的应用及它们的特点，并提出了在我国聚乙烯发展过程中，优先采用气相流化床工艺的建议。     

改性炭黑对多相聚烯烃/炭黑导电复合材料阻温特性的影响

以高密度聚乙烯(PE-HD)为基体,研究了不同组分及炭黑(CB)改性方法对PE/聚丙烯(PP)/CB多相聚烯烃导电复合材料阻温特性的影响.结果表明,在PE中添加PP能显著降低材料的室温体积电阻率,适量的CB能够提高材料的正温度系数(PTC)强度.经过硝酸和过硫酸钾改性的CB能够有效提高复合材料的导电性和PTC强度,其中硝酸改性的CB能与聚烯烃形成强物理吸附,使CB粒子高温下更容易分开,PTC强度比未改性时提高了25.65％.此外,改性CB能使复合材料的NTC效应降低,其中过硫酸钾使CB表面氧含量增加,提高了CB在聚烯烃中的吸附力,抑制高温团聚,经过硫酸钾改性CB的复合材料的NTC强度从未改性的0.675降低到改性后的0.339.     

Unipol工艺聚乙烯产品开发的进展

综述了Unipol工艺开发第一代及第二代乙烯（共）聚合物产品的进展情况，以及相关联的催化剂和工艺的科技进步。     

聚烯烃的功能化

叙述了聚烯烃通过共聚、接枝、高分子反应、低分子量化、复合化、交联化以及新的催化技术开发所得各种功能性聚烯烃的特点及其应用。     

Autooxidation of Oriented Polyolefins

Abstract

The effect of the chemical structure of the polymer on its reactivity in the oriented state is studied, and causes of the effect of orientation drawing of polyolefins on the oxidation kinetics are identified.

The orientation drawing of the polymer is shown to be dependent on the nature of the latter which can either delay or accelerate the oxidation process. The effect of a delayed rate of oxidation for the samples of one drawing degree is determined by the nature of the side substitute in the monomeric link of the polymer.

The effect of the orientation drawing of the polymer on the change of parameters of oxidation (k ₂ k ₆ ^?0.5 [RH]), a decrease of the coefficients of solubility and diffusion of oxygen as well as the change in the polymer structure depending on its nature are considered.

Analysis of structural changes in the polymers due to orientation has shown that drawing of the polymer can result in localization of oxidation in defected zones of amorphous areas isolated from each other by transition chains in extremely straightened conformation. In this case, the oxidation kinetics of oriented polyolefins can be described with the use of postulates of the “zone” model developed by Yu. A. Shlyapnikov. Evaluation of the kinetic parameters of oxidation (k _2eff, k _6eff, θ) with the use of this model is made.

It is shown that the effect of the nature of the polymer is due to a change in activity of the C?H bonds participating in the oxidation process, peculiar features of changes in the structure and physical properties of the polymer in the process of orientation drawing, in terms of the “zone” model, to the rate of the expansion of the oxidation center, that is, the nature of the polymer determines the parameters k _2eff, k _6eff, θ in the oriented sample.     

分步反应的气相催化氧化法生产蒽醌

介绍了分步反应的气相催化氧化法生产蒽醌的新工艺及主要设备，阐述了工艺的重要特点。     

Spheripol工艺生产高抗冲聚丙烯

介绍了Spheripol工艺生产高抗冲聚丙烯产品的方法,采用两步复合工艺生产嵌段聚丙烯,第1步采用环管反应器进行丙烯液相均聚反应,第2步采用流化床反应器进行丙烯均聚物与乙烯单体气相共聚反应,即在气相反应器中,利用来自环管反应器中的均聚物的残余活性,加入乙烯和补充的丙烯及氢气实现乙-丙共聚,共聚物的生成使最终产品的抗冲性能大大提高,尤其是低温下的抗冲性能。     

AS法煤气脱硫工艺的生产实践

回顾了我国ＡＳ法煤气脱硫工艺的生产历程,总结了该工艺的生产操作要领,指出了各厂生产中所存在的问题及其改进的途径,最后对ＡＳ法煤气脱硫工艺作出了客观的评价。     

亲水性聚烯烃纤维的改性方法研究进展

聚烯烃以其优异的性能、低廉的价格和越来越广泛的用途,日益成为一种重要的合成高分子材料的主体。但它极弱的亲水性限制了在一些领域的应用。介绍了近几年国内外通过化学接枝、等离子体接枝、辐射接枝、表面光接枝等方法对聚烯烃表面亲水性改性的研究进展。     

双甲精制工艺在合成氨工业中的应用进展

通过9年来双甲精制工艺的实际运行，证明该工艺具有操作简便，生产稳定，事故发生率低及环境污染小的特点。经过不断的改进和完善，该装置已显示出独特的优越性，创造了较大的经济效益和社会效益。     

气相法全密度聚乙烯高效催化剂的研究

主要讲述了一种结构式为[(MgBuCl)_p,(MgCl(?))](?)[Ti(OBu)xCl_y]_b(THF)_c[(C_eH_(?)_2AlCl]_d的齐格勒-纳塔型催化剂的制备方法.该催化剂具有活性高、共聚能力强、氢调敏感的特性,并且在气相聚合反应过程中放热均匀、操作稳定,适合在我国引进的大型气相流化床工艺装置上使用.     

Fused Deposition Modeling of Polyolefins: Challenges and Opportunities

Polyolefins are the largest class of commercially available synthetic polymers that are extensively used in a variety of applications from commodities to engineering owing to their low cost of production, good physico-mechanical properties, light weight, good processability, and recyclability. Compared to conventional molding techniques, fused deposition modeling (FDM)-based 3D printing is a smart manufacturing technology for thermoplastics due to its low cost, ease of production of complex geometrical parts, rapid prototyping, and scalable customization. FDM 3D printing can be an ideal manufacturing technology for polyolefins to manufacture various complex parts. However, FDM 3D-printing of polyolefins is challenged bycritical printing problems like high warpage, dimensional inaccuracies, poor bed adhesion, and poor layer-to-layer adhesion. In this review, a fundamental understanding of polyolefins and their FDM 3D-printing process is established, and the recent progress of FDM 3D printing of polyolefins is summarized. Furthermore, strategies to overcome warpage and to improve mechanical strength of the 3D-printed polyolefins are provided. Finally, future prospectives of FDM 3D-printing of polyolefins are critically discussed to inspire prospective research in this field. It is believed that this review article can be tremendously useful for research work related to FDM of polyolefin-based materials.