几种配合剂对环氧化天然橡胶性能的影响

研究了氢氧化镁、氧化锌及硬脂酸对环氧化天然橡胶（ＥＮＲ）硫化特性、硫化胶的力学性能及老化性能的影响。结果表明：加入２份氢氧化镁可有效地提高ＥＮＲ的硫化速度、拉伸强度和抗热氧老化性能；氧化锌和硬脂酸对硫化胶网络的完善是不可缺少的。用差示扫描量热法（ＤＳＣ）比较了几种防老剂（防老剂Ｄ，Ｈ．ＷＳＰ，ＭＢ．４０１０，ＳＰ）在ＥＮＲ中的防护效果。结果表明防老剂Ｄ的效果最好。以防老剂Ｄ与防老剂ＭＢ并用，加入２份氢氧化镁、２份硬脂酸和５份氧化锌，不仅可缩短硫化时间，而且可大幅度提高硫化胶的拉伸强度、扯断伸长率和老化系数。     

环氧化天然橡胶贮存性能的差异

对环氧化天然橡胶（ENR）及其胶乳（ENRL）进行了为期2年的贮存试验，考察其外观和主要物理性能的变异状况，探讨了这些性状变异的机理，了解到ENR和ENRL原材料长期贮存，其外以观无明显变化。     

新型防老剂RT-1对天然橡胶性能的影响

研究新型防老剂RT-1对天然橡胶(NR)性能的影响。结果表明:加入防老剂RT-1,NR胶料的ML增大,MH减小,t90和ts1延长,老化后NR硫化胶的拉伸性能较好,热氧化活化能增大;防老剂RT-1对NR硫化胶热氧老化的防护效果优于防老剂BHT和4010NA。     

促进剂品种对环氧化天然橡胶动态性能的影响

采用橡胶加工分析仪研究促进剂M,TMTD和NS对环氧化天然橡胶(ENR)动态性能的影响.结果表明:采用不同促进剂的ENR胶料的硫化程度不同,硫化胶的动态性能对频率、应变和温度的响应不同;采用促进剂NS的ENR硫化胶具有较高的剪切储能模量和较低的损耗因子,其动态性能较好.     

天然橡胶与环氧化天然橡胶并用硫化胶的相结构及其物理性能

研究了天然橡胶(NR)与环氧化天然橡胶(ENR）并用胶的相结构对并用胶性能的影响。并用动态力学分析和电子显微照片分析了并用胶的结构。动态力学分析和电子显微照片表明，不同配比的NR／ENR并用胶具有多相结构，且在ENR的何种分数接近0.35时产生共连续相转换。相结构对并用胶的气密性和耐油性有很大影响。     

环氧化天然橡胶改性淀粉/天然橡胶复合材料性能的研究

采用环氧化度适中的环氧化天然橡胶(ENR-25)改性淀粉/NR复合材料,并对其性能进行研究。结果表明:添加ENR-25可以显著提高改性淀粉/NR复合材料的物理性能和耐磨性能,降低淀粉/NR复合材料作为胎面胶时的滚动阻力,改善抗湿滑性能;当ENR-25用量为5份时,复合材料的综合性能较好。     

新工艺环保型防老剂264对天然橡胶热氧老化性能的影响

对比普通防老剂264,研究新工艺环保型防老剂264（简称新型防老剂264）对天然橡胶（NR）胶料的硫化特性、热氧老化性能及其耐水抽出性能的影响。结果表明,与普通防老剂相比,新型防老剂264对NR胶料的硫化特性影响不明显,其耐水抽出性能及胶料的耐热氧老化性能较好,更适合在潮湿的环境下使用。新型防老剂264在NR胶料中的用量以1～2份为宜。     

环氧化天然橡胶与配方设计

叙述了环氧化天然橡胶（ＥＮＲ）及其与ＰＶＣ，ＥＰＤＭ并用的配方设计与物理性能。     

Effect of Some Polymeric Phenolic Antioxidants on the Properties of SBR Vulcanizates

Polymeric antioxidants can be useful in the protection of styrene-butadiene rubber (SBR) against thermal oxidative aging as an alternative to the low molecular weight ones, which migrate out of the rubber articles. Three polymeric compounds were prepared and incorporated into SBR mixes to be evaluated as antioxidants in comparison with the commercial antioxidant, N-isopropyl-N′-phenyl-p-phenylenediamine (IPPD). The rheometric characteristics of the produced SBR mixes were measured and the cure time was determined. The mechanical, swelling, extraction, and compression properties were studied. The results obtained revealed that poly(4-mercaptophenyl)acrylamide has superior effect in the protection of SBR articles against thermal oxidative ageing.     

Influence of Fillers and Curing Systems on the Physico-Mechanical Properties and Stability of EPDM Vulcanizates

ABSTRACT

The thermal stability was investigated for ethylene propylene diene terpolymer (EPDM) rubber loaded with different white and black fillers, namely, kaolin, quartz, polyvinylchloride PVC, talc, graphite, medium thermal carbon black MT, semi reinforcing furnace black SRF, and high abrasion carbon black HAF. The fillers were added at a fixed level of 20 phr. Two curing systems were used, tetramethyl thiuram disulfide (TMTD) and sulfur/N-cyclohexyl-2-benzothiazyl sulfenamide (S/CBS). The effects of the curing system and type of filler on the physico-mechanical properties, before and after thermal aging were investigated. It was found that the vulcanizates cured with S/CBS system gave better physico-mechanical properties than the TMTD cured samples. However, TMTD cured EPDM has thermal stability performance superior to the other vulcanizing system.     

抗氧剂对聚醚抗老化性能的影响

不同聚醚由于其下游应用需求不同,对抗氧剂的需求也不同。普通软泡聚醚在发泡应用时由于发泡配方中含水量高,发泡温度比较高,泡沫的烧芯问题是抗氧剂要解决的关键问题,U-pack B7033可以满足应用需求;对于高回弹聚醚,由于其主要应用是汽车领域,除了考虑泡沫的抗烧芯性能外,还要考虑添加的抗氧剂对聚醚及聚氨酯泡沫的醛酮含量以及VOC的影响,U-pack B7170可以满足应用要求;CASE聚醚用抗氧剂除了要考虑聚醚的储存稳定性外,还要考虑下游制备聚氨酯预聚体时的颜色稳定性,U-pack B7522可以满足应用要求。     

Evaluation of New Thermal Stabilizers and Antifatigue Agents for Rubber Vulcanizates

Seven organo-phosphorus compounds were synthesized and incorporated in natural rubber (NR) and styrene-butadiene rubber (SBR) mixes. The rheometric characteristics of the green rubber mixes were determined using the oscillating disc rheometer. The prepared compounds were evaluated as thermal stabilizers and antifatigue agents in NR and SBR vulcanizates. The results revealed that the prepared compounds were good antioxidants and antifatigue agents for rubber vulcanizates exceeding the commercial antioxidant 4-methyl-2,6-di-tert-butyl phenol, which is used in the rubber industry. In addition, the efficiency of such compounds depends on their chemical structure.     

防老剂对氯化聚乙烯橡胶性能的影响

研究不同防老剂对氯化聚乙烯橡胶(CM)性能的影响.结果表明:加入不同防老剂的CM胶料ML和MH减小,t10和t90延长,CM硫化胶的硬度、100％定伸应力和拉伸强度增大,拉断伸长率减小;交联密度随老化时间的延长而呈增大趋势.当防老剂RD用量为2份时,CM硫化胶的耐热氧老化性能最优.     

Thermal Aging Properties and Molecular Transport of Solvents through Vulcanizates Prepared from Thioglycollic Acid Modified Epoxidized Low Molecular Weight Natural Rubber Blends Filled with Admixtures of Carbon Black and Carbonized Rubber Seed Shell

Physico-mechanical, aging, swelling, solubility, and permeability properties of blends of natural rubber and thioglycollic acid modified epoxidized low molecular weight natural rubber (TGA-ELMWNR) filled with admixtures of carbon black and carbonized rubber seed shell (CRSS) in ketones, alcohols, aldehydes, and petroleum fuels (petrol, kerosene, and diesel) were investigated as a function of different filler composition. The physico-mechanical properties were found reducing as the level of CRSS increases, but were within the accepted level for natural rubber compounds, showing that CRSS can find uses as fillers in materials of low tensile strength. The aging results of all the mixes were nearly of the same magnitude. The swelling and solubility results showed that ketones swell the vulcanizates more and faster than alcohols and than aldehydes. The sorption, diffusion, and permeability of the blends as determined by the gravimetric method confirm the better resistance of blends with higher ratio of carbon black. Petrol was found diffusing through the vulcanizates faster than kerosene and faster than diesel. Above all, replacement of carbon black with 15% carbonized rubber seed shell has not shown any serious deleterious effects on the vulcanizates.     

EPDM/ENR共混胶力学性能的研究

探讨了三元乙丙橡胶(EPDM)和环氧化天然橡胶(ENR)的共混比、加料顺序、硫化体系对EPDM/ENR共混物的硫化特性、力学性能和耐热空气老化性能的影响。结果表明,共混比不同,共混胶的性能均有差异,且共混物的力学性能低于单组分的线性加和值,但综合比较而言,当EPDM/ENR=40/60时共混胶的力学性能较好;在所研究的四种加料顺序中,以配合剂先与EPDM制成母炼胶后再与ENR共混的这一种加料顺序下所得的共混物硫化胶的力学性能最好;采用半有效硫化体系所制得的共混物硫化胶的力学性能较好。     

硅烷含硫原子数对NR硫化胶性能的影响

研究了Ｓｉ６９系列的硅烷偶联剂对ＮＲ胶料力学性能和耐磨性能的影响。试验结果表明，硫原子数影响力学性能和耐磨性，但基本上不影响它们随硫化时间下降的趋势。另外，硫原子数对力学性能和耐磨性、以及耐磨性随硫化时间下降趋势的效应填充体系（炭黑、炭黑、／白炭黑）而异。     

热处理对环氧化天然橡胶性能的影响

研究了热处理对环氧化天然橡胶 (ENR)和NR物理性能的影响。结果表明 ,随加热时间的延长 ,ENR生胶门尼粘度、硫化胶定伸应力增大 ,拉伸强度和扯断伸长率下降 ;NR硫化胶拉伸强度稍有下降 ,生胶门尼粘度、硫化胶定伸应力和扯断伸长率基本保持不变     

A Comparative Study on Curing Characteristics,Mechanical Properties,Swelling Behavior,Thermal Stability,and Morphology of Feldspar and Silica in SMR L Vulcanizates

Abstract

Comparison studies on effects of feldspar and silica (Vulcasil C) as a filler in (SMR L grade natural rubber) vulcanizates on curing characteristics, mechanical properties, swelling behavior, thermal analysis, and morphology were examined. The incorporation of both fillers increases the scorch time, t ₂, and cure time, t ₉₀, of SMR L vulcanizates. At a similar filler loading, feldspar exhibited longer t ₂ and t ₉₀ but lower values of maximum torque, M_HR, and torque difference, M_HR–M_L than did silica-filled SMR L vulcanizates. For mechanical properties, both fillers were found to be effective in enhancing the tensile strength (up to 10 phr), tensile modulus, and hardness of the vulcanizates. However, feldspar-filled SMR L vulcanizates showed lower values of mechanical properties than did silica-filled SMR L vulcanizates. Swelling measurement indicates that swelling percentages of both fillers-filled SMR L vulcanizates decrease with increasing filler loading whereas silica shows a lower swelling percentage than feldspar-filled SMR L vulcanizates. Scanning electron microscopy (SEM) on fracture surface of tensile samples showed poor filler–matrix adhesion for both fillers with increasing filler loading in the vulcanizates. However, feldspar-filled SMR L vulcanizates showed poorer filler–matrix adhesion than did silica-filled SMR L vulcanizates. Thermogravimetric analysis (TGA) results indicate that the feldspar-filled SMR L vulcanizates have higher thermal stability than do silica-filled SMR L vulcanizates.