二甲基二氯硅烷的提纯

制备硅油,硅橡胶,尤其是制备硅橡胶时,要求所用单体二甲基二氯硅烷有很高的純度,即在99.98％以上,如果所包含的不純物甲基三氯硅烷量超过0.05％,就不能得到高分子量的易溶于苯、甲苯等溶剂的链状聚合体,而只能得到不溶于溶剂的三向結构的聚合体,这种具有交联結构的聚合体是无法洗除在聚合时所用的触媒而且在混练时又不容易和填料均匀地混合,因此会严重地影响硅橡胶的热稳定性、电絕緣、机械强度等性能。     

四丁基氢氧化鏻(TBPH)的制备及其催化性质

有机硅氧烷聚合成硅油和硅橡胶所用的瞬时催化剂在完成聚合后,适当升高温度即可分解,失去催化活性,否则催化剂的存在会在升温时引起高聚物的分解,目前均以四甲基氢氧化铵为瞬时催化剂,其受热(约130℃)后可分解生成甲醇和三甲胺：     

硅橡胶合成方面的进展

硅橡胶从1944年在美国投入生产后发展很快,每年的增产率平均在40%。美国1960年的年产量达到了3000吨以上。目前除了美国以外至少有5个国家,10个以上工厂能够大量地生产。据估计这些国家的年产量的总和已超过了美国的年产量。为了适应航空、电机等现代工业的发展,硅橡胶在生产技术及质量方面也有了很大提高,出现了一些新的合成和工艺方法及很多新的品种。关于最普通的硅橡胶,即二甲基硅橡胶,其合成方法的概要如下(参阅文献[3]):将从“直接法”所得的二甲基二氯硅烷     

加成型液体硅橡胶的研究进展

结合加成型液体硅橡胶的硫化原理,综述了加成型液体硅橡胶导热性能、耐高温性能及粘结性能的最新研究进展,发现加入金属氮化物导热填料是提高加成型液体硅橡胶导热性能的有效途径;改善分子结构是提高加成型液体硅橡胶耐高温性能的主要途径;共混粘结促进剂是提高加成型液体硅橡胶粘结性能的重要途径。介绍了加成型液体硅橡胶的最新应用领域,提出功能化加成型液体硅橡胶,如3D个性化打印硅橡胶、人体器官硅橡胶、高折光封装硅橡胶等功能材料是未来加成型液体硅橡胶的发展方向。     

四丁基氢氧化(TBPH)的制备及其催化性质

有机硅氧烷聚合成硅油和硅橡胶所用的瞬时催化剂在完成聚合后,适当升高温度即可分解,失去催化活性,否则催化剂的存在会在升温时引起高聚物的分解.目前均以四甲基氢氧化铵为瞬时催化剂[1～3] ,其受热(约1 3 0℃)后可分解生成甲醇和三甲胺:(CH3) 4NOH (CH3) 3N + CH3OH即不再与聚合物作用,但三甲胺有鱼腥味,含有百万分之几就足以污染聚合物,而从高聚物中除去残存的三甲胺又十分困难.近年来,化妆品市场对硅油的需求量日益增加,但三甲胺的存在会严重影响化妆品的质量.尽管采取各种手段(如水洗、吹除等)试图解决其腥味问题[2 ] ,但并不理想.…     

硅橡胶弹性行为的研究进展

硅橡胶特别是补强硅橡胶因其良好的抗疲劳性、高阻抗性以及宽的使用温度域而广泛地应用于工业的诸多方面.能够从网络结构上对硅橡胶材料的性能进行合理的解释、模拟以及预测是多年来很多研究者的追求.本文概述了部分过去的相关理论研究,即基于设计一定的理论模型对硅橡胶网络结构进行模拟并预测其性能的模拟理论,重点介绍了具有阶段性意义的经典模拟模型并说明其基本假设、实际应用范围以及缺陷所在,阐述了近些年来新的一些从分子角度计算模拟的研究成果,并与经典的网络模型进行比较,以找到一个到目前为止,综合模拟性能好、适用性强的模拟研究方法.     

石墨烯改性硅橡胶研究进展

依据硅橡胶优异的热稳定性,有望应用于航天航空领域,但由于其自身的力学性能较差限制了它的应用。本文综述了力学性能、电性能和热稳定性优异的石墨烯改性硅橡胶的应用研究。介绍了石墨烯改性硅橡胶复合材料的四种制备方法——乳液共混法、溶液共混法、熔融共混法和机械共混法,重点综述了机械共混法制备石墨烯改性硅橡胶复合材料,比较并分析了石墨烯改性硅橡胶复合材料性能影响因素及其研究现状,发现国内外研究石墨烯改性硅橡胶主要用于硅橡胶的电性能研究,最后,对石墨烯改性硅橡胶复合材料的应用前景进行了展望。     

耐高温高导热硅橡胶的研究与应用进展

概述了导热硅橡胶的种类、组成、固化机理和应用及发展方向。分析了硅橡胶的热老化机理,概述了几种提高硅橡胶耐热老化性能的方法,指出添加含杂原子聚硅氧烷是提高硅橡胶耐热性和综合性能的一条非常重要的有效途径。同时系统阐述了导热硅橡胶的导热理论和机理及提高硅橡胶导热性的方法,概述了导热填料的种类、晶体结构、粒径及制法、取向和纤维化及表面处理和复合杂化对硅橡胶导热性能的影响。     

阻燃及可瓷化硅橡胶成炭结构的研究进展

简单介绍了硅橡胶的阻燃和瓷化机理。依据阻燃剂、填料及炭层结构的不同,将硅橡胶分为阻燃和可瓷化两大类.综述了阻燃硅橡胶和可瓷化硅橡胶的阻燃性能和成炭结构的研究进展。分析表明:添加物理或化学膨胀型阻燃剂的硅橡胶,燃烧过程中形成的炭层疏松多孔,阻燃隔热性能优异,但炭层强度差;添加非膨胀型阻燃剂的硅橡胶,炭层结构相对密实,但表面不平整,存在孔洞和裂缝,阻燃效果不好;添加可瓷化填料的硅橡胶燃烧形成的陶瓷炭层坚硬而致密,具有优异的耐火持久性,但在隔绝热量方面不如膨胀炭层。炭层的疏松隔热与坚固耐久兼顾是阻燃硅橡胶未来可能的发展方向。     

钛酸钾晶须对热硫化硅橡胶性能的影响

研究了钛酸钾晶须对热硫化硅橡胶复合材料的硫化特性、力学性能及热稳定性的影响,通过扫描电镜观察了复合材料的断面及晶须在基体中的分散性。结果表明:钛酸钾晶须能促进硅橡胶的硫化,提高其最高扭矩;同时,钛酸钾晶须对硅橡胶具有一定的补强作用,拉伸强度、硬度等随晶须用量的增加而增大;钛酸钾晶须的引入,使硅橡胶复合材料的热稳定性明显提高,填充量为9vol%时,与纯硅橡胶相比,复合材料的热分解温度提高了65℃,Kissinger法求出填充量为12vol%的钛酸钾晶须/硅橡胶复合材料的热分解活化能为193.62kJ/mol,高于相同填充量的白炭黑/硅橡胶复合材料,具有较好的热稳定性。     

Radiation effects on polymers—VI. Enhancement of radiation vulcanization of styrene-butadiene rubbers mixes using two-component sensitizers

Different combinations of various multifunctional monomers and halogen co-agents were used to sensitize the radiation vulcanization of styrene-butadiene rubber (SBR). It was found that combinations of various vinyl compounds with hexachloroethane give rise to vulcanizates with considerably better physico-mechanical properties than those obtained in the presence of one of the two components. The enhancement of vulcanization depends upon the type of the vinyl co-agent used and on the concentrations of the sensitizers. The dose required to achieve vulcanizates with satisfactory physico-mechanical properties was reduced to 3–5 Mrad. Infra-red spectrophotometric analysis, supported by swelling and solubility tests, indicated that the co-agent most probably became a part of the vulcanized rubber. The mechanism of vulcanization in the presence of the two-component co-agent system is suggested.     

COORDINATION CROSSLINKING OF NITRILE RUBBER FILLED WITH COPPER SULFATE PARTICLES

By incorporating copper sulfate(CuSO_4)particles into acrylonitrile butadiene rubber(NBR)followed by heat pressing,a novel vulcanization method is developed in rubber through the formation of coordination crosslinking.This method totally differs from traditional covalent or non-covalent vulcanization approaches of rubber.No other vulcanizing agent or additional additive is involved in this process.By analyzing the results of DMA,XPS and FT-IR,it is found that the crosslinking of CuSO_4 particles filled NBR was induced by in situ coordination between nitrogen atoms of nitrile groups (-CN)and copper ions(Cu~(2 ))from CuSO_4.SEM and EDX results revealed the generation of a core(CuSO_4 solid particle)- shell(adherent NBR)structure,which leads to a result that the crosslinked rubber has excellent mechanical properties. Moreover,poly(vinyl chloride)(PVC)and liquid acrylonitrile-butadiene rubber(LNBR)were used as mobilizer to improve the coordination crosslinking of CuSO_4/NBR.The addition of PVC or LNBR could lead to higher crosslink density and better mechanical properties of coordination vulcanization.In addition,crystal water in CuSO_4 played a positive role to coordination crosslinking of rubber because it decreased the metal point of CuSO_4 and promoted the metal ionization.     

双组份室温加成型硅橡胶口腔印模材料的制备

以自制乙烯基硅油为基胶、自制含氢硅油为交联剂、铂配合物为催化剂、高纯度硅微粉为填料、多乙烯基化合物为抑制剂等,通过实验制得双组份室温加成型硅橡胶口腔印模材料.研究了各组分对硅橡胶印模材料硫化化时间、细微复制、力学性能的影响.并制备了与国外产品性能相当的产品.     

Effects of cellulose nanocrystals on the vulcanization of natural rubber/cellulose nanocrystals nanocomposite and corresponding regulating strategies

Vulcanization is a vital process in rubber processing, it endows rubber with valuable physical and mechanical properties, making rubber a widely used engineering material. In addition to vulcanization agent, reinforcing fillers play a non-ignorable influence on the vulcanization of rubber nanocomposites. Herein, the effects of cellulose nanocrystals (CNCs) on the vulcanization of natural rubber (NR)/CNCs nanocomposite was studied. It was found that even though the addition of CNCs can effectively improve the dispersion of ZnO in NR matrix, the vulcanization of NR was inhibited. This may be attributed to the CNCs' adsorption of vulcanizing agents (DM, ZnO) and the acidic chemical environment on the surface of CNCs. In order to improve the vulcanization properties of NR/CNCs nanocomposite, tetramethyldithiochloram (TMTD) and triethanolamine (TEOA) were used as a combination accelerator and curing activator, respectively, and polyethylene glycol (PEG) was introduced to screen hydroxyl groups on the surface of CNCs to prohibit the CNCs' adsorption of vulcanizing agents. The results indicate that TMTD and TEOA effectively improved the vulcanization rate of NR/CNCs nanocomposite and increased the crosslink density by an order of magnitude. Subsequently, the tensile strength, tear strength, and so forth. of NR/CNCs nanocomposite were significantly improved. However, PEG hardly help to improve the vulcanization properties of NR/CNCs nanocomposite. In addition, the control samples without CNCs were prepared and characterized, the comparation between NR and NR/CNCs nanocomposite shows that the synergistic effect of crosslink density and CNCs' reinforcement more effectively improve mechanical properties of NR. This work not only elucidates the inhibiting mechanisms of CNCs on the vulcanization of NR, but also provides practical strategies for improving the vulcanization and properties of NR/CNCs nanocomposite. It may accelerate the application of CNCs as rubber reinforcing filler.     

间甲钴黏合体系在轮胎骨架材料中的黏合机理研究

为验证与进一步探索黏合树脂及钴盐对轮胎与镀铜钢丝帘线的增黏作用机理,选取传统黏合树脂R80与2种新型黏合树脂HT1005和H620,通过对2种新型黏合树脂的结构分析、橡胶硫化特性、静态T抽出测试与力学性能测试,并设计了一种新的黏合层强度测试方法与黏合层表征方法,进行机理探索,得出如下结论:含有羟基的极性黏合树脂在橡胶硫化时,会由于与非极性天然橡胶的极性差异产生的热力学不相容从而产生自动相分离,向橡胶与镀铜钢丝的界面层进行迁移汇集,且极性越高迁移能力越强,产生一个介于橡胶与镀铜钢丝之间的树脂富集层.因为黏合树脂交联反应温度为140℃左右,会在天然橡胶硫化反应时发生同步交联反应,黏合树脂形成的网络模量高于橡胶硫化网络,会增强镀铜钢丝与橡胶之间的黏合层强度,并形成一个镀铜钢丝与橡胶之间的模量过渡层,进一步增强黏合层.且极性越强,树脂网络交联程度与橡胶硫化网络交联程度越接近,增黏效果越好;钴盐会活化橡胶中的S,使更多的S迁移到镀铜钢丝表面从生成更多硫化亚铜键,增强黏合.     

硅氢加成型室温固化硅橡胶胶粘剂的研究

<正> 我们研制了一种硅氢加成型室温固化硅橡胶,这种橡胶不但有较好的力学性能,而且与各类材料如金属、塑料、陶瓷、玻璃等都有很好的粘结力,是一种具有弹性的胶粘剂。该胶粘剂是利用一种含乙烯基聚硅氧烷、含氢聚硅氧烷以及二氧化硅补强剂在铂催化剂     

炭黑结合橡胶对天然橡胶性能的影响

本文研究了天然橡胶(NR)与五种不同类型炭黑的结合橡胶对其混炼胶的应力-应变、流变性质等的影响。结果表明,NR与炭黑的结合橡胶量随炭黑结构和表面积增加而增加。结合橡胶的增加使NR在低剪切下的本体粘度、弹性恢复性和强度增加,塑性和粘着性降低;在高剪切下流动性变差,挤出物收缩则有所下降。此外,结合橡胶的增加也增加了硫化胶的交联度,因此模量、硬度和耐磨性提高,抗张强度和伸长率却有所下降。     

Studies of conventional sulfur vulcanization of SBR rubber: Analysing the reaction products from thermal degradation of the accelerator by means of MCC-IMS technique

A combination of knowledge on curing process of rubber mixes with novel methods of chemical analysis, a new unconventional approach to analysis of rubber vulcanization is presented in this study. Six SBR samples containing various N-tert-butyl-2-benzothiazole sulfenamide (TBBS) accelerator: sulfur ratios (within) the range of conventional (CV) sulfur vulcanization system were studied using multi-capillary column ion mobility spectrometry (MCC-IMS) technique. For these analysis, calibration/dilution curves were established. Moreover, data from MCC-IMS were correlated with other parameters of the rubber vulcanizates – their crosslink density and structure as well as their tensile strength and modulus at elongation. For such comparison, one of the reaction products from thermal decomposition of TBBS, benzothiazole was selected. Furthermore, the concentration of benzothiazole released during the vulcanization process corresponded well with the crosslink density of the rubber vulcanizates studied. It was even possible to calculate the crosslink density from the concentration of benzothiazole determined by MCC-IMS, using Boltzmann fitting curve. The presented results could be an important contribution in understanding the mechanisms occurring during rubber vulcanization, demonstrating a new approach to testing and evaluation of the process.     

Techniques used for determining cure kinetics of rubber compounds

Controlling and assuring the quality of the manufacture of high precision engineering rubber components has led to the need to simulate fundamental industrial processes such as compression molding and injection molding using CAE tools. Both compression and injection molding techniques for the fabrication of rubber products involve crosslinking or vulcanization which is invariably assisted by temperature and pressure. Vulcanization is a chemical process and therefore its simulation necessarily involves characterization of kinetic parameters. The kinetics of curing or vulcanization is somewhat complex as it depends upon the compound formulation, temperature and in some cases pressure. The present paper reports and discusses the application and utility of different techniques for characterizing the cure behavior of rubber compounds. Kinetic data has been fitted to various mathematical models in order to see which of the models can best represent the crosslinking behavior of selected rubber compounds. Finally, the kinetic data is used to simulate the injection molding process for relatively simple geometries.     

Effects of vulcanization accelerator functionalized graphene on the co-vulcanization kinetics and mechanical strength of NR/SBR blends

Rubber blends are widely used for combining the advantages of individual rubber component. However, to date, how to determine and distinguish the vulcanization kinetics for each single rubber phase in rubber blends during the co-vulcanization process are still a challenge. Herein, high resolution pyrolysis gas chromatography-mass spectrometry (PyGC-MS) was employed for the first time to investigate the vulcanization kinetics of natural rubber (NR) and styrene-butadiene rubber (SBR) in their blends filled with graphene. It is shown that the crosslinking rate of NR chains (k_NR) was much lower than that of SBR chains (k_SBR) in the unfilled blends and blends with untreated graphene. Interestingly, the gap between k_SBR and k_NR was narrowed effectively in the blends with vulcanization accelerator grafted graphene, showing a better co-vulcanization of NR and SBR. In addition, the vulcanization accelerator grafted graphene was uniformly dispersed in rubber matrix and endowed rubber blends with higher mechanical strength and thermal conductivity did the untreated graphene.