含氯聚合物和橡胶的自交联共混物

综述了聚氯乙烯、氯磺化聚乙烯、氯丁橡胶等聚合物物其他橡胶之间的自交联反应。介绍了共混物的交联机理、相容性和力学性能。     

AOP降解含酚含氯混合废水的研究

以主波长为254nm的紫外光灯为光源,TiO2为光催化剂,对苯二酚和五氯酚钠混合废水的光催化降解。研究了各种因素如催化剂的活化温度、TiO2的用量、溶液的初始浓度以及酸度对降解率的影响。并对降解机理进行了初步探讨。     

药物氯甲双磷酸钠的热氧降解过程及动力学研究

通过用热重法(TG)、微分热重法(DTG)和差热分析法(UTA)研究药物氯甲双磷酸钠(NaHPO_3)_2CCI_2·4H_2O)在空气流中的热氧降解过程和热氧降解动力学,发现其热氧降解过程由四个紧连步骤组成.用Coats-Redfern方程进行动力学处理,确定该药物热氧降解的表观反应级数分别为1、1.2、1.1、1.3和反应活化能为112kJ/mol、301Kj/mol、217.4kJ/mol、108.7kJ/mol.     

光催化氧化法降解含氯有机物的研究进展

对光催化降解含氯有机物的机理,影响含氯有机物光催化降解速率的因素,提高光催化降解含氯有机物效率的途径以及光催化降解含氯有机物的研究进展进行了综述.     

聚合物降解和稳定问题国际研讨会

1988年10月10日到13日,在莫斯科苏联科学院化学物理研究所召开了聚合物降解和稳定问题国际研讨会。参加者有保加利亚、匈牙利、民主德国、古巴、波兰、罗马尼亚、苏联和捷克斯洛伐克的学者。研讨会是在社会主义国家科学院“聚合物稳定和老化”问题合作的范围内组织的。这个问题的合作有三个主要方面:“抗氧剂”、“光稳     

金属铁及其化合物降解含氯化合物的研究进展

综述了金属铁,金属铁／钯,ＦｅＳ２,Ｆｅ２Ｏ３,Ｆｅ＾Ⅱ４Ｆｅ＾Ⅲ２（ＯＨ）１２ＳＯ４ｙＨ２Ｏ等物质在降解四氯化碳,氯仿１,１,２,２－四氯乙烷,氯乙烯、三氯乙烯,四氯乙烯、多氯联 等含氯化合物中的应用以及降解机理。     

塑料降解与稳定化（Ⅱ）：热降解与热稳定（中）

2塑料热稳定 2．1提高塑料热稳定性的可能途径 2．1．1添加热稳定剂 大量研究和实践表明,对于常规的使用条件．添加“热稳定剂”是抑制塑料热降廨、提高其热稳定性的最经济有效方法。显然,由于不同塑料的具体热降解机理不同,因此热稳定剂也各不相同。但是概括起来,塑料热稳定剂至少应具有以下三种功能之一：     

聚碳酸酯的热降解

综述了聚碳酸酯的热稳定性及其影响因素,并详细论述了一些添加剂如偶联剂甲基三甲氧基硅烷、钛酸四丁酯、阻燃剂二苯砜磺酸钾(KSS)、聚氨丙基苯基倍半硅氧烷(PAPSQ)等对聚碳酸酯热稳定性的影响,阐述了Kissinger法和Ozawa法等聚合物热降解动力学的分析方法。重点介绍了近期国内外有关聚碳酸酯热降解产物和热降解机理方面的研究成果。     

有机锡热稳定剂对CPE脱氯化氢热降解性的影响

采用刚果红法研究有机锡热稳定剂对氯化聚乙烯(CPE)脱氯化氢热降解性的影响。结果表明，硫醇锡复合热稳定剂T-137和T-395A抑制CPE脱氯化氢的效果优于非硫醇锡热稳定剂二月桂酸二丁基锡；环氧大豆油能协同二月桂酸二丁基锡减慢CPE脱氯化氢速度；热稳定剂用量小于3份时，二月桂酸二丁基锡／二盐基亚磷酸铅和二月桂酸二丁基锡／硬脂酸钡并用体系(并用比1：1)抑制CPE脱氯化氢的效果较二月桂酸二丁基锡差，热稳定剂用量为3份时则较好。     

热重法测定聚合物热降解反应动力学参数进展

概述热重法测定聚合物热降解反应动力学参数的方法,主要分为定温法、非定温法和高解析法三类,而每一类中又包括几种方法。通过对各种方法的分析,指出了它们的优缺点,对正确选择研究方法具有一定的指导意义。     

Thermal stability and degradation mechanism of C60 fullerene-based polymers

In this paper, the thermal stability and degradation mechanisms of C₆₀ fullerene-based polymers, obtained by click polymerization between dialkyne-substituted C₆₀ derivative monomers and 1,3,5-tris(dodecyloxy)benzene-based diazide comonomers, were evaluated. The activation energy of the fullerene polymer C₆₀P2 with an ethylene spacer, determined under peak degradation rate conditions, was lower than that of the counter polymer C₆₀P1 with a methylene spacer, suggesting lower thermal stability of C₆₀P2. The combined technique of thermogravimetric analysis—mass spectroscopy and Fourier transform infrared spectroscopy revealed that the thermal decomposition onset of the analyzed samples is accompanied by C C cleavage of the dodecyloxyside chain groups, followed by the decomposition of the 1,2,3-triazole, dicarboxylate and benzoate moieties. It was found that no thermal decomposition of the fullerene carbon cage occurs up to 670°C. Molecular modeling with Hyperchem software version 7.5 confirmed that C₆₀P1 is more thermally stable than C₆₀P2.     

Thermal degradation of some perfluoroalkylene-linked polymers

Poly (1,3-phenylenehexafluorotrimethylene) and perfluoroalkylene-linked polyanhydride, polycarbonate and polyester have been studied by thermogravimetry, pyrolysis–gas chromatography–mass spectrometery and fluoride ion analysis. The thermal stability is governed by the ease of formation of specific cyclic degradation products.     

Exactly alternating silarylene—siloxane polymers: 6. Thermal stability and degradation behaviour

The thermal stability and degradation behaviour of a series of twelve different exactly alternating silarylene—siloxane polymers were investigated by several different methods including thermal gravimetric analysis (t.g.a.) in air and in nitrogen, long term (up to 48 h) high temperature (600° and 900°C) isothermal degradation in nitrogen, and rapid pyrolysis in helium. No weight loss was observed by t.g.a. until about 400°C, and two distinctly different mechanisms were observed, one for degradation in nitrogen (a single step process), and the other in air (a three step process). Under nitrogen, black, insoluble, carbon-hydrogen-silicon containing degradation products were obtained, which were stable in pure oxygen to at least 1100°C. In air, pure SiO₂ was obtained after heating to above 730°C. Isothermal investigations revealed that at temperatures of 600°C and above, weight loss by thermal degradation under a nitrogen atmosphere was completed in less than an hour, and the polymeric products which remained thereafter did not change any further even after 48 h at 900°C.     

Thermal stability and flammability of organic polymers

Attempts have been made to assess the importance of the thermal instability of organic polymers as a factor governing their flammability. In general, however, there is little correlation between the susceptibility of polymers to undergo thermal decomposition and the readiness with which these materials burn. Although certain additives which exhibit flame-retardant activity do raise the temperature at which polymers start to break down, the ability of these compounds to increase polymer stability makes no appreciable contribution to their inhibiting action on the combustion of polymeric materials. Nevertheless studies of the thermal behaviour of additives incorporated into polymers can provide useful information aboút the interactions which occur between polymers and additives during the combustion process.     

Thermal stability of p-phenylene sulphide polymers

The thermal stability of a series of linear and branched p-phenylene sulphide polymers at 350° has been evaluated by differential thermal analysis, thermogravimetric analysis and weight-loss studies. It has been concluded that there is some indication that the thermal stability increases with the degree of branching present in the polymer and that the stability can be further improved by a preliminary heat treatment in the absence of air. The mechanism of ageing appears to involve a combination of crosslinking, chain scission and oxidation reactions.     

Thermal degradation of high nitrile barrier polymers

Effects of absorbed moisture on degradation behavior of high nitrile barrier polymers were monitored using thermogravimetric analysis techniques. Non-modified and 10 percent rubber modified samples were heated isothermally at nitrile processing temperatures (200°C to 240°C) in air and nitrogen environments. Degradation was evaluated in terms of weight loss as a function of heating time and sample coloration. It was determined that complete removal of moisture, as well as high moisture concentration, contribute to increased degradation at the temperatures evaluated. Moisture levels in the range of 0.15 to 0.5 percent were found to minimize degradation. Heating environment, time, temperature, and rubber modification were also found to influence thermal stability.     

Thermal degradation studies of perchlorate-doped conductive polymers

The thermogravimetric behavior of polypyrrole (PPY), polybithiophene (PBT), and poly-aniline (PAN) perchlorate complexes and their corresponding base polymers have been studied. The PBT–perchlorate complex and base polymer decompose at significantly lower temperatures than do the PPY and PAN counterparts. All three perchlorate complexes retain half or more of their original conductivities with no changes in the doping levels after one cycle of heating to 150°C in air and cooling to room temperature. However, after heating at 150°C for 24 h, only the PAN–perchlorate complex shows no significant change in the doping level, although its conductivity decreases by more than two orders of magnitude. X-ray photoelectron spectroscopy analyses of the perchlorate complexes reveal the presence of at least two distinct chlorine species. The thermal decomposition of the perchlorate anions results in the formation of volatile chlorine species as well in chlorine covalently bonded to the polymer. The thermal decomposition of the PPY–perchlorate complex also results in the conversion of positively charged nitrogens to iminelike structures.     

Thermal degradation of nitrogen-containing polymers, acrylonitrile-butadiene-styrene and styrene-acrylonitrile

Thermal degradation of nitrogen (N)-containing recycled plastics (styrene-acrylonitrile (SAN), acrylonitrilebutadiene-styrene (ABS)) was carried out in a stirred-batch reactor at 300–400 ‡C under nitrogen stream. The degradation oil began to be generated over 300 ‡C. Recycled SAN plastic was converted to oil with 91.3 wt% yield at 380 ‡C, while only 70.9 wt% of recycled ABS plastics was converted to oil at the same temperature and both oils contained about the same 3.7 wt% nitrogen as an elemental basis. Rate of oil formation from the thermal degradation of SAN was much higher than that of ABS, but showed a similar degradation pattern in terms of chemical composition. In oil products, aromatic contents obtained at 360 ‡C were 70 wt% for SAN and 79 wt% for ABS, respectively, and decreased to 59 wt% and 57 wt% at 380 ‡C with increasing degradation temperature. Dominant product of both degradation oils was styrene, and the following was ethylbenzene for ABS, but none in case of SAN. Both oils contained the N-containing plastic additives that give rise to a confusion for the identification of authentic N-containing degradation products.