PS阻燃改性研究进展

综述了阻燃聚苯乙烯(PS)的研究现状和发展方向。总结分析了卤系阻燃体系、磷系阻燃体系、膨胀型阻燃体系、硅系阻燃体系、金属氢氧化物阻燃体系等对PS的阻燃研究现状,综述了本体阻燃PS和添加型阻燃PS的阻燃改性方法,如共聚、共混及通过悬浮聚合法制备阻燃PS的优势和不足。通过科学合理的阻燃改性方法,研发新型、高效的阻燃体系是今后PS阻燃改性研究的重点和发展方向。     

阻燃聚苯乙烯/层状无机纳米复合材料的研究进展

综述了阻燃聚苯乙烯(PS)/蒙脱土(MMT)纳米复合材料、阻燃PS/双氢氧化物(LDH)纳米复合材料、阻燃PS/石墨烯(GO)纳米复合材料的阻燃性能和热稳定性能,利用添加型或反应型阻燃剂制备的上述3种复合材料的阻燃性能和热性能都有大幅度的提高。最后展望了阻燃PS/层状无机纳米复合材料的研究和应用前景。     

MWCNTs／PS复合材料阻燃性能研究

以多壁碳纳米管、表面处理MWCNTs、MWCNTs/纳米氧化钛复合对聚苯乙烯(PS)进行阻燃改性.通过热失重(TG)和氧指数(LOI)测试等方法,测试MWCNTs/PS、MWCNTs/nano-TiO2/PS复合材料的阻燃性能和热稳定性;利用扫描电镜、傅立叶红外光谱法研究复合材料的微观形态结构.研究表明:少量的MWCNTs可提高PS的阻燃性能,混合酸溶液处理的MWCNTs对PS的阻燃改性效果比未处理的MWCNTs要好;当MWCNTs添加量达到3.0Wt%时,该复合材料的氧指数达到22,可以较大地减少燃烧熔融滴落;MWCNTs(1.0Wt%)/nano-TiO2(5.0Wt%)/PS复合材料的氧指数达到23,说明MWCNTs与nano-TiO2具有协同阻燃效果.     

阻燃聚苯乙烯研究进展

介绍了聚苯乙烯(PS)的阻燃方法,包括本体阻燃、卤素阻燃、磷系阻燃、无机阻燃,膨胀阻燃、黏土阻燃等,分析了各种阻燃PS的阻燃机理,并指出了阻燃PS复合材料的发展方向。     

十溴二苯乙烷阻燃聚苯乙烯的性能研究

本文采用十溴二苯乙烷(DBDPE)新型阻燃剂对聚苯乙烯(PS)进行阻燃改性，研究了DBDPE的阻燃机理、其与Sb2O3的协同阻燃效应及其对PS阻燃性能、物理机械性能的影响。结果表明，DBDPE与DBDPO阻燃效果相当，偶联剂处理后的DBDPE与Sb2O3复合阻燃剂协同阻燃的PS具有良好的综合性能。     

阻燃PS的流变性能

在聚苯乙烯(PS)中填充十溴二苯醚或共混溴化聚苯乙烯(BPS)得到阻燃PS。借助毛细管流变仪,研究了阻燃PS的流变性能。结果表明：阻燃PS熔体表观黏度（ηa）随剪切速率的增大而减小、随温度的升高而降低,具有假塑性流体的特性;填充十溴二苯醚的阻燃PS的叼。比纯PS显著降低,黏流活化能(Eη)为40．74kJ／mol,200～220℃时,非牛顿指数(n)为0.35-0．43;共混BPS的阻燃PS的ηa与纯PS接近,Eη为75.32kJ／mol,200～220℃时,n为0．48～0．57。     

锡酸盐/十溴二苯醚阻燃体系对聚苯乙烯的阻燃消烟作用

研究了锡酸盐/十溴二苯醚(DBDPO)阻燃体系与 Sb_2O_3/DBDPO 阻燃体系对聚苯乙烯(PS)的阻燃消烟作用。通过热重分析和差热分析研究了阻燃 PS 从室温到800℃的热降解过程,探讨了不同体系的阻燃机理。结果表明,锡酸盐阻燃剂体系处理的样品极限氧指数最高为27.8%,烟密度等级最低为68.37%,与未经阻燃剂处理的样品相比具有较好的阻燃消烟性能。加入 Fe~(3+)、Co~(2+)、Ni~(2+)、Cu~(2+)等可改变 PS 的热降解过程,对 PS 第一阶段的降解起催化作用,并且有效地促进炭化物的生成,提高材料的阻燃消烟性能。     

环境友好聚苯乙烯阻燃技术新进展

介绍了近年来环境友好阻燃聚苯乙烯(PS)的研究进展,分别从反应型阻燃剂和添加型阻燃剂展开阐述。反应型阻燃剂相对于添加型阻燃剂能为PS提供更高的阻燃效率和力学性能,并提出无卤、高效、低烟、低毒、多功能的新型PS阻燃材料的研究开发将是当今的发展方向。     

无机物浸渍聚苯乙烯泡沫塑料阻燃性能的研究

采用无机水泥填充聚苯乙烯(PS)泡沫,并重点研究了其对PS的阻燃性能的影响。结果表明:MgSO_4和MgO混合后制备的无机阻燃剂不仅可以提高PS泡沫板的阻燃性能,同时还可以作为增强相提高PS泡沫板的压缩强度。当MgSO_4:MgO:H_2O加入质量比为5:5:10时,PS阻燃板能较好地包裹PS颗粒阻燃层,同时还具有较低的导热系数和密度,适合于保温层和楼体建筑外层的应用。     

三嗪系列阻燃剂在PS中阻燃规律性的研究

较系统地研究了几种三嗪系列阻燃剂在PS泡沫中所显示的阻燃规律性。试验证实其阻燃性大小为:TCC相似文献   

苯菌灵亚慢性毒性试验染毒饲料分析

介绍了苯菌灵在亚慢性毒性试验所用饲料中的液相色谱分析方法,并对该药在染毒饲料中的均一性、稳定性和实际浓度进行了监测。结果表明,该药剂在亚慢性经口毒性试验染毒剂量是准确的。     

木脂素合成中单体的氧化偶联研究简介

木脂素是由两分子苯丙素聚合而形成的一类天然化合物,广泛存在于自然界中,其中大多数木脂素为游离的状态,小部分与糖结合成苷而存在于植物的木部和树脂中,所以称之为木脂素,而最近又在动物体内发现了有别于植物木脂素的哺乳动物木脂素[1].由于大部分木脂素具有很高的抗癌、抗肝炎、杀虫等生物活性,因此被广泛的应用于在医药、农业以及日化等方面,木脂素的合成一直是有机合成中的一个热点[2],而合成木脂素的偶联条件的选择是木脂素合成中起到关键性因素,文章就几种重要木脂素的合成方法中单体的氧化偶联方式进行简单的介绍.     

PIG清焦技术在炼厂加热炉的实践

某厂焦化装置加热炉对流段结焦严重需要清焦,通过比较各种清焦技术的利弊,采用了清焦效果好、对炉管损伤小、工期短、安全环保的PIG清焦技术,清焦后加热炉运行效果良好,延长了装置的开工周期,具有很大的推广价值。     

膜催化技术用于甲烷转化反应的研究进展

介绍了膜催化技术在甲烷转化反应中的应用,这些过程包括甲烷氧化偶联反应制乙烯,甲烷部分氧化制甲醇,甲烷水蒸气重整制合成气等,通过膜催化反应与传统催化反应的比较,揭示了膜催化技术的优点。     

Role of the unsaturated group in the radiation-induced crosslinking of polyethylene in the presence of chlorotrifluoroethylene

The effect of unsaturated groups on the crosslinking of polyethylene in the presence of chlorotrifluoroethylene (CTFE) has been studied. Butadiene- and isoprene-grafted polyethylenes with high concentrations of unsaturated groups were crosslinked more markedly than the original polyethylenes. The rate of gel formation increased with the increase in the initial concentration of unsaturated group in polyethylenes, while the rate of grafting of CTFE decreased. The concentration of unsaturated group decreased rapidly during the course of the reaction. The rate of decrease in each unsaturated group was in the order, vinylidene > vinyl >trans-vinylene. In the irradiation of polyethylene with a high concentration of unsaturated groups in CTFE, the number of grafted monomers was almost equal to the decrease in numbers of the unsaturated group. These results are discussed in relation to the reaction mechanism and the estimated activation energy of the elementary reaction     

Changes in the energy characteristics of the surface of organosilicate coatings in the course of formation

The influence of the parameters of curing of organosilicate coatings and the degree of completeness of interfacial chemical reactions on the total surface energy, its dispersion and polar components, and the physicochemical and protective properties of coatings is analyzed. The possibility of using organosilicate coatings as easily cleanable materials is determined by the small values of the surface energy and its polar component.     

Role of the lymphatic system in the transport of absorbed 7,12-dimethylbenzanthracene in the rat

To determine the role of the intestinal lymphatic system in the absorption of a polycyclic aromatic hydrocarbon, 7,12-dimethylbenzanthracene, a radiolabeled preparation of the compound was given by intraduodenal infusion to rats in doses of 10 μg, 10 mg and 20 mg in olive oil solution. The hydrocarbon appeared to be absorbed from the intestine in a fractional manner, ca. 20% of the administered radioactivity being recovered totally in bile and intestinal lymph in 24 hr at all three dose levels. Biliary radiolabel accounted for 75–82% of combined recovery of radioactivity in bile and lymph with all three doses. The recovery of significant amounts of radiolabel in bile before the appearance of isotope in lymph, together with the fact that the biliary radiolabel greatly exceeded at all times the lymphatic recovery of isotope, suggests that an alternative pathway, presumably the portal venous route, is of major importance in the transport of the absorbed hydrocarbon.     

Improvements in the two-parallel-condenser model of the double layer in the presence of organic adsorption

Previous recent attempts by the author for giving a more consistent physical meaning to the two-parallel-condenser model and its implications on the adsorption isotherm behaviour are reviewed. In addition, the displacement of oriented water molecules by the adsorbate is taken into account and the effects of a series capacity are discussed. This allows to consider the original expression for the charge density as a function of potential as an approximation of a model much more complex than that first treated. The new expression for the limiting capacity at maximum coverage still allows a consistent analysis from the corresponding experimental parameters.