对氨基水杨酸镧对天然橡胶硫化特性的影响

以氯化镧和对氨基水杨酸钠为原料,采用沉淀法合成了新型环保促进剂对氨基水杨酸镧(PAS-La)。通过元素分析、热分析和红外光谱分析等方法对产物进行了表征并确定其分子式为La(C₇H₆NO₃)₃·H₂O。利用无转子硫化仪、平衡溶胀法和万能试验机考察了PAS-La对天然橡胶硫化特性、交联密度和力学性能的影响,并对硫化动力学进行了分析。结果表明,随着PAS-La添加量的增加,天然橡胶的正硫化时间存在最大值,焦烧时间先减小后增大;硫化胶的交联密度增大,力学性能明显增强。当PAS-La的添加量为1.2份(质量)时,其对天然橡胶的硫化促进作用达到最佳。动力学计算发现,随着PAS-La添加量的增加,交联前驱体的反应活性增强,活化能先减小再增大。     

对甲基苯甲酸镧铈的合成及对天然橡胶的硫化促进作用

以对甲基苯甲酸为配体、稀土镧铈为中心体合成了对甲基苯甲酸镧铈,通过傅里叶变换红外光谱、热分析及元素分析对其进行了表征.将其作为硫化促进剂添加到天然橡胶中,测定了添加量不同时胶料的硫化曲线和硫化参数,进行了溶胀实验,并根据硫化动力学模型对硫化曲线进行了非线性拟合,求得了硫化各阶段的活化能.结果表明,对甲基苯甲酸镧铈的加入...     

低温硫化NR/BR并用胶的硫化特性及其力学性能研究

采用异丙基黄原酸钠SIP、N-乙基-N-苯基二硫代氨基甲酸PX的复合促进剂体系(用量分别为1.5phhr和0.5phhr)可使天然橡胶/顺丁橡胶并用胶(并用比为70∶30)在90℃~95℃内快速硫化,硫化特性符合缓冲胶工艺的要求,但其性能与HG/T 4124-2009《预硫化缓冲胶》存在一定的差距。     

用核磁共振法研究促进剂对硫黄硫化天然橡胶结构的影响

用核磁共振交联密度仪研究了次磺酰胺类促进剂NS、DZ和CZ对天然橡胶硫化胶结构的影响,考察了相同用量下促进剂种类与天然橡胶硫化胶交联密度的关系.结果表明,在基本配方和硫化条件相同的情况下, 促进剂的相对分子质量越低,天然橡胶硫化胶的交联密度越高.硫化胶的交联密度不仅对核磁共振的横向弛豫时间有影响,而且影响其纵向弛豫时间.随着交联密度的增加,硫化胶的核磁共振弛豫时间缩短,弛豫时间对温度的依赖性减弱.     

抗硫化返原剂的合成与应用

参考二元促进剂体系的设计,合成抗硫化返原剂O,O-二丁基二硫代磷酸二硫化物(TBuPD)、1,6-双(二丁基二硫代磷酸)己烷(DBPH)、1,6-双(二苄基二硫代氨基甲酰)己烷(DBTH),探究其对天然橡胶的硫化性能、交联结构和力学性能的影响。结果表明,DBTH、TBuPD和DBPH的加入使混炼胶在150℃下硫化60 min后的硫化返原率从8.2%降低到3.8%以下;硫化胶在长时间的硫化后均有良好的力学性能保持率;硫化胶在长时间的硫化后滚动阻力降低。     

促进剂NS对环氧化天然橡胶硫化特性与力学性能的影响

研究促进剂NS用量对环氧化程度为25的环氧化天然橡胶(ENR 25)的硫化特性、交联密度、力学性能及耐热空气老化性能的影响。研究结果表明,当硫磺用量一定时,ENR25的焦烧时间T10与正硫化时间T90随着促进剂NS用量的增加而延长,硫化速率指数Vc逐渐下降,MH-ML值逐渐增大;ENR25硫化胶的交联密度随着NS用量的增加而增大;当NS用量为1. 2phr,ENR25硫化胶的拉伸强度达到最佳值,随着促进剂NS用量的增加,ENR25硫化胶的撕裂强度逐渐增大;随着促进剂NS用量的增加,ENR25硫化胶的耐热空气老化性能提高。     

二硫代氨基甲酸镧双配体稀土促进剂第二配体对三元乙丙橡胶性能的影响

研究二乙基二硫代氨基甲酸-二苯胍-镧(LaDC-D)、二乙基二硫代氨基甲酸-硫脲-镧(LaDC-TU)、二乙基二硫代氨基甲酸-2-巯基苯并咪唑-镧(LaDC-MB)和二乙基二硫代氨基甲酸-2,6-二叔丁基-4-甲基苯酚-镧(LaDC-BHT)4种双配体稀土促进剂对三元乙丙橡胶(EPDM)性能的影响,并与单配体稀土促进剂二乙基二硫代氨基甲酸镧(LaDC)进行对比。结果表明:与LaDC相比,LaDC-D具有较好的硫化促进活性,两种配体发生了较好的协同活化作用,混炼胶的t90明显缩短,硫化胶的交联密度增大;第二配体为具有防老效果的两种双配体稀土促进剂LaDC-MB与LaDC-BHT硫化胶的撕裂强度较高,抗切割性能和耐热氧老化性能较好,其中LaDC-MB硫化胶的耐热氧老化性能最好;双配体稀土促进剂不仅能有效提高混炼胶的硫化效率,而且能改善硫化胶的耐热氧老化性能,为橡胶多功能助剂的开发提供了新思路。     

二丁基二硫代氨基甲酸镧的合成及其在丁苯橡胶中的应用

研究了二丁基二硫代氨基甲酸镧配合物的合成,以工业级的二丁基二硫代氨基甲酸钠与氯化镧为反应物,采用液-液合成法合成了二丁基二硫代氨基甲酸镧,作为硫化促进剂应用于丁苯橡胶的基础配方中。结果表明二丁基二硫代氨基甲酸镧对丁苯橡胶的硫化性能有下列作用：延长燃烧时间,提高碳化速率。提高材料力学性能。     

像胶硫化促进剂Pz的合成

通过对硫化促进剂二甲基二硫代氨基甲酸锌(简称硫化促进剂Pz)的各种合成方法进行实验研究和比较,结果认为氧化锌一步法合成工艺较佳,较佳的工艺条件为:反应温度<30℃,反应时间2h,原料配比二甲胺:二硫化碳:氧化锌=1:1.1:0.5(mol比)。     

几种配合剂对平衡硫化体系NR胶料性能的影响

探讨促进剂、多功能助剂PA、防焦剂苯甲酸和白炭黑对平衡硫化体系NR胶料硫化特性和物理性能的影响。试验结果表明，采用促进剂D／NOBS并用的NR胶料焦烧时间较长和正硫化时间较短，硫化胶的拉伸强度、拉断伸长率和撕裂强度较高；加入多功能助剂PA使胶料的焦烧时间略有延长，硫化胶的拉断伸长率提高；采用苯甲酸作防焦剂可以大幅度缩短胶料的正硫化时间，提高硫化胶的拉伸强度、拉断伸长率和硬度；白炭黑和偶联剂Si69(质量比100／3)直接加入的胶料正硫化时间明显缩短，硫化胶的拉断伸长率和撕裂强度较大。     

铂催化加成型液体乙烯基硅橡胶性能

制备了两种铂催化剂：氯铂酸-二乙烯基四甲基二硅氧烷和氯铂酸-异丙醇,比较了其在加成型液体乙烯基硅橡胶的制备中的催化作用,并着重分析了氯铂酸-二乙烯基四甲基二硅氧烷（Karstedt型）催化荆加入量对硅橡胶性能的影响。结果表明,氯铂酸-二乙烯基四甲基二硅氧烷的活性比氯铂酸-异丙醇的活性大;在一定范围内,随着催化剂用量增加,硅橡胶硫化时间缩短,介电常数和介电损耗增加;当氯铂酸-二乙烯基四甲基二硅氧烷催化剂质量分数为1．15×10^-5时,硅橡胶固化良好,介电常数和介电损耗较小且随频率变化较稳定。     

挤出用溴化丁基橡胶硫化体系的研究

溴化丁基橡胶几种典型硫化体系的对比实验,结果表明,用氧化锌体系硫化的溴化丁基橡胶具有良好的焦烧安全性,比较适宜于挤出用;加入促进剂HVA-2,可显著提高胶料的硫化速度和交联程度,并改善焦烧安全性;当氧化锌用量为4份,HVA-2用量为1.5份时,胶料具有较佳的综合物理性能和加工安全性。     

反式聚异戊二烯的硫化特性及硫化胶的性能

研究了反式－１,４－聚异戊二烯（ＴＰＩ）的硫化特性及硫化程度对其力学性能的影响。结果表明：采用硫黄－促进剂ＣＺ 硫化体系时,ＴＰＩ的硫化曲线较为理想;硫化使得ＴＰＩ的力学性能在硫黄用量达到一定值时发生突变,由硬质材料转变为软质橡胶,即从硫化三阶段中的第二阶段过渡到第三阶段。     

New binary systems containing TMTD‐amidino phenyl thiourea and CBS–amidinophenyl thiourea for the vulcanization and rheological behavior of natural rubber latex

The use of accelerators in rubber latex is basically different from their use in dry rubber. In the present study, N amidino N'phenyl thiourea (APT) which is more nucleophilic than thiourea was studied as a secondary accelerator along with tetra methyl thiuram disulphide (TMTD) and N‐cyclohexylbenzothiazyl sulphenamide (CBS) in the vulcanization of natural rubber latex. These binary systems were found to be very effective in reducing the vulcanization time. The optimum dosages for this non‐toxic secondary accelerator required were derived. Rheological studies of the compounded latex show that the introduction of APT in these systems does not have adverse effect in processing in comparison with the thiourea systems. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Studies on novel binary accelerator system in sulfur vulcanization of natural rubber

The synergistic activity of binary accelerator systems in rubber vulcanization is well known. Binary accelerator systems are being widely used in industry and are becoming increasingly popular because of the fact that such mixed systems can effectively prevent prevulcanization, permit the vulcanization to be carried out at a lower temperature in a shorter time, and produce a vulcanizate with superior mechanical properties compared to those of a stock cured with a single accelerator. Thiourea and its derivatives are important secondary accelerators in this context. It is suggested that thiourea containing binary accelerator systems cause rubber vulcanization to proceed by a nucleophilic reaction mechanism. In the present study 1‐phenyl‐5‐ortho, ‐meta, and ‐para‐tolyl derivatives of 2,4‐dithiobiurets, which are more nucleophilic than thiourea and vary in their nucleophilic reactivity, are used as secondary accelerators along with 2‐morpholinothiobenzothiazole in the vulcanization of natural rubber. The results show an appreciable reduction in the cure time for the mixes containing the dithiobiurets compared to the reference mix. These results are indicative of a nucleophilic reaction mechanism in the vulcanization reaction under consideration. These vulcanizates also demonstrate comparatively better tensile properties and good retention of these properties after aging. An attempt is also made to correlate the variation in physical properties to chemical crosslink formation in the various vulcanizates. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3173–3182, 2003     

Studies on novel binary accelerator system in sulfur vulcanization of natural rubber

The synergistic activity of binary accelerator systems in rubber vulcanization is well known. Thiourea and its derivatives are important secondary accelerators in this context. It is suggested that thiourea containing binary systems of rubber vulcanization proceed by a nucleophilic reaction mechanism. Amidinothioureas (ATUs), which are derivatives of thiourea, have been investigated extensively as secondary accelerators. One of the aims of this study was to get further proof with regard to the theory of the nucleophilic reaction mechanism in such binary systems. In the present study phenyl substituted ATU was used as a secondary accelerator along with mercaptobenzothizyl disulfide, tetramethyl thiuram disulfide, or cyclohexyl benzthiazyl sulfenamide in the sulfur vulcanization of natural rubber. The results showed an appreciable reduction in the cure time for the mixes containing the ATU compared to the reference mixes. These results are indicative of a nucleophilic reaction mechanism in the vulcanization reaction under review. These vulcanizates also showed comparatively better tensile properties and good retention of these properties after aging. The optimum dosages of the secondary accelerator required for these vulcanization reactions were also derived. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1–8, 2001     

氯丁橡胶244与天然胶共混性能研究

摘要:本文主要研究了硫化体系和补强体系对氯丁橡胶与天然胶共混时性能的影响,其中主要涉及到氧化锌、氧化镁、普通硫磺、DM作为硫化体系以及碳黑N550和白炭黑作为补强体系时对共混胶料物理机械性能的影响。经过研究发现：氧化锌：氧化镁：普通硫磺：DM硫化促进剂=6：3：5：0.3时,扯断强度能达到：23.18MPa,硫磺对硫化胶料绍尔硬度的影响最大,硫化时间为60min时得到的物理机械性能最好,碳黑N550为40份、白炭黑为20份时,硫化胶料的物理机械性能最好。     

橡胶硫化促进剂的研究进展

概述了橡胶硫化促进剂的结构、类型、性能以及橡胶硫化反应机理的研究进展、硫化促进剂的性能表征方法。指出了国内外硫化促进剂的发展趋势。     

A new secondary accelerator for the sulfur vulcanization of natural rubber latex and its effect on the rheological properties

The vulcanization of natural rubber (NR) latex can be effectively carried out at low temperatures by using binary accelerator systems containing thiourea (TU) as a secondary accelerator. It was reported that sulfur‐containing nucleophiles such as thiourea enable the primary accelerator to become effective even at low temperatures, indicating a nucleophilic reaction mechanism in such vulcanization reactions. In the present study, a derivative of thiourea [viz. aminoiminomethyl thiourea (AMT)], which is more nucleophilic than thiourea, is used as a secondary accelerator in the sulfur vulcanization of NR latex. One of the aims of this study was to give conclusive evidence for a nucleophilic reaction mechanism. The synergistic effect of the above thiourea derivative with primary accelerators such as tetramethylthiuram disulfide (TMTD), zinc diethyldithiocarbamate (ZDC), and cyclohexylbenzthiazyl sulfenamide (CBS) was studied at two different temperatures (viz. 100 and 120°C). These binary systems were found to be very effective in reducing the optimum cure time of the different mixes compared to control formulations containing TU. The optimum amount of the secondary accelerator required was also determined. Mechanical properties such as tensile strength and tear strength of the vulcanizates were also evaluated. Chemical characterization of the vulcanizates was carried out by determining the total crosslink density. Values of the cure characteristics evaluated support a nucleophilic reaction mechanism in these vulcanization reactions under review. The effect of this secondary accelerator on the rheological behavior of compounded latex is also studied and was found not to affect adversely. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2781–2789, 2004