透明脱醇型单组分室温硫化硅橡胶

介绍了透明脱醇型单组分室温硫化硅橡胶的制备工艺及配方，对其硫化性能、操作性能、贮存稳定性及硫化胶的机械性能和粘接性能进行了测试。结果表明，以端二甲氧基甲基硅基聚二甲基硅氧烷为基础聚合物、有机钛络合物作催化剂、适量的增粘剂构成的透明脱醇型ＲＴＶ－１硅橡胶的硫化、操作及贮存稳定性好，胶料黄变小，硫化胶机械强度：１００％定伸应力０．４４ＭＰａ，拉伸强度２．３９ＭＰａ，扯断伸长率７０６％，对不锈钢、黄铜、铝及塑料等材料的粘接均为１００％内聚破坏。     

硫化体系对氟橡胶26在硫化氢环境中耐老化性能的影响

以3撑硫化剂、双酚AF／BPP、DCP／TAIC三种硫化体系硫化的氟橡胶26为实验材料,采用美国Cortest公司生产的高压釜测试系统,依照NACE标准对其进行不同温度下硫化氢老化试验,研究了三种硫化体系对氟橡胶26硫化特性、物理性能和耐硫化氢老化性能的影响。结果表明：采用3#硫化剂硫化体系的氟橡胶硫化特性、物理性能相对较好;不同温度下氟橡胶在气相中含硫化氢气体、试样置于液相的腐蚀环境腐蚀后,3#硫化剂硫化体系氟橡胶硬度较高,拉伸性能较好,耐硫化氢性能相对较好,但其体积变化率在不同的温度下均超过20％,很难满足硫化胶条件下的使用。     

Adhesion of Natural Rubber Compounds to Plasma-Polymerized Acetylene Films

Plasma-polymerized acetylene films were shown to be novel, highly effective primers for rubber-to-steel bonding. However, the performance of the primers depended strongly on processing variables such as the substrate pretreatment and the carrier gas. Miniature lap joints were prepared by using natural rubber as an “adhesive” to bond together pairs of pretreated steel adherends primed with plasma-polymerized acetylene films which were deposited using various carrier gases. The initial strength of joints prepared from substrates which were mechanically polished and then coated with plasma-polymerized acetylene films deposited using an argon or nitrogen carrier gas was 2000 N for a bonded area of 64 mm² and failure was 100% cohesive in the rubber. Similar results were obtained for joints prepared from mechanically-polished brass substrates. However, the initial strength of joints prepared from polished substrates which were coated with plasma-polymerized films deposited using oxygen as a carrier gas was lower by a factor of two and there was only 30% rubber coverage on the substrate failure surfaces. demonstrating the importance of the carrier gas.

The initial strength of joints prepared from substrates which were pretreated by alkaline cleaning, acid etching, or mechanical polishing and then coated with plasma polymers using argon as the carrier gas was also approximately 2000 N/64 mm² and failure was again 100% cohesive in the rubber. However, the strength of joints prepared from substrates which were pretreated by ultrasonic cleaning in acetone and then coated with plasma polymers using argon as the carrier gas was lower by a factor of almost two, demonstrating the significance of substrate pretreatment.

During exposure to steam at 121°C, the durability of miniature lap joints prepared from polished steel substrates primed with plasma-polymerized acetylene films using argon as a carrier gas was excellent. After exposure for 3 days, the breaking strength of the joints decreased slightly, from 1740 to 1410 N/64 mm², but the locus of failure remained cohesive in the rubber, implying that effect of steam was mostly to reduce the cohesive strength of the rubber. Similar results were obtained from joints prepared from polished brass substrates. However, the durability of joints prepared from polished brass substrates and from polished steel substrates primed with plasma-polymerized acetylene was poor during exposure to aqueous salt solutions for three days. Although all of the joints decreased significantly in breaking strength, the strength of the joints prepared from brass substrates was about 400 N/64 mm² higher than that of joints prepared from steel primed with plasma-polymers. Most of the joints prepared from steel primed with plasma-polymerized acetylene films failed near the interface between the primer and the steel substrate although some specimens had 20-40% rubber coverage on the failure surfaces.     

抗静电氧化锌晶须对热硫化硅橡胶性能的影响

研究了抗静电用氧化锌晶须对热硫化硅橡胶的硫化特性、力学性能及电性能的影响。结果表明：在硅橡胶硫化初期氧化锌晶须能加速硫化反应、在硫化后期延迟硫化反应，可提高其最低扭矩和最高扭矩；硫化胶的硬度增加，拉伸强度、扯断伸长率有所降低，表面电阻率和体积电阻率降低。     

Improving adhesion properties between rubber compound and brass-plated steel cord by the addition of epoxidized natural rubber to rubber compound

The adhesion between a rubber compound containing epoxidized natural rubber (ENR) and a brassplated steel cord was studied to shed light on the role of ENR for the improvement of adhesion. The addition of ENR in the rubber compound caused cure rate to decrease, and as ENR loading increased, modulus and hardness increased while tensile strength and elongation at break decreased. An improvement of adhesion was obvious with low loading of ENR at the range of 2 phr, while an adverse effect was observed with higher concentrations of 10 phr. Since the ratio of sulfur to copper at the interphase of the rubber compound/brass film adhesion sample increases with increased ENR loading up to 2 phr, the acceleration of sulfide formation by ENR could be proven. Adequate curing of rubber and the formation of high-molecular layer at the interphase by addition of small amount of ENR improve adhesion. However, the toughening of the rubber caused by the addition of larger amounts of ENR degrades the adhesion due to the poor physical properties of the rubber compound.     

共混比对丁腈橡胶/氯醚橡胶性能的影响

研究了共混比时常规共混及动态硫化共混丁腈橡胶(NBR)／氯醚橡胶(ECO)的力学性能及加工流变性能的影响。结果表明,共混比对NBR／ECO胶料的力学性能及加工流变性能影响显著。NBR经动态硫化后,压缩永久变形及挤出胀大明显减小,拉伸强度提高,表现黏度随ECO用量的增大而减小。共混比对常规共混胶的表观黏度影响不大。动态硫化有利于改善NBR／ECO胶料的加工性能。     

Promotion effect of a chlorotriazine derivative on the adhesion between rubber compounds and a brass-plated steel cord

The adhesion between chlorotriazine derivative (TZ)-loaded rubber compounds and a brass-plated steel cord was studied to understand how TZ acted as an adhesion promoter. With the loading of the rubber compound with TZ, the cure rate became slow, but changes in the physical properties were not significant. An improvement in adhesion was obvious at a low TZ loading ranging from 0.5 to 2.0 phr. An adverse effect was observed with high loadings up to 8 phr and aging treatments for 15 days. Since the concentration of sulfur in the interphase of the rubber compound/ brass film adhesion samples after humidity aging was high for the rubber compound with high loadings of TZ, the acceleration of sulfide formation by TZ loading was confirmed. Lack of oxygen in the interphase indicated the conversion of zinc oxide to zinc sulfide in the rubber compound containing TZ. The control of zinc oxide formation in the adhesion interphase by TZ is suggested to be the reason for the adhesion promotion by TZ.     

Role of Sn on the adhesion in Cu–Sn alloy-coated steel–rubber interface

Cu–Sn coatings with varying Sn content were deposited on steel substrate by immersion route and the effect of variation of Sn content and the substrate roughness on the interfacial adhesion strength of Cu–Sn-coated steel substrates vulcanized with styrene butadiene rubber were investigated. The surface roughness of the coatings did not vary compared to pristine steel substrate with change in Sn weight% in the coatings. The coated surfaces exhibited bare spots or deep trough as micro-discontinuities in the coatings, where formation of Fe₂O₃ was evident from SEM-EDS, AES, and XPS analysis. Microstructural study of the coating cross-section and coating-substrate interface by transmission electron microscopy of cross-sectioned samples revealed inadequate penetration of coating inside these troughs. Peel test carried out on the Cu–Sn-coated steel–rubber joints showed mixed mode i.e. adhesive and cohesive mode of interfacial fracture irrespective of the coating composition. The peel test further indicated higher interfacial adhesion strength for Cu–Sn-coated samples than pure Cu-coated samples, with an optimum adhesion strength for the coatings containing 3–4?wt.% Sn.     

纳米SiOx改性室温硫化硅橡胶研究

介绍了纳米SiOx改性双组份室温硫化硅橡胶（RTV－2）的研究情况。对胶液的凝胶时间测试表明，纳米SiOx对RTV－2胶具有较强的阻聚作用；硫化胶拉伸性能测试结果表明，纳米SiOx质量分数为6％时，硫化胶的拉伸强度达到2.8MPa，断裂伸长率达到97％。     

Mechanism of adhesion degradation of rubber to brass-plated steel cords

We have explored the effect of the presence of the sulfide layer on the corrosion performance of sulfidized brass-coated steel cords extracted from tires and squalene formulations. The corrosion performance of sulfidized brass cords extracted from various rubber formulations was tested in 3% NaCl electrolyte solution using DC polarization techniques. We found that the copper sulfide layer made the sulfidized brass cords passive and protected them from corroding in severe corroding environment (3% NaCl). The degree of protection offered by the sulfidized brass cords was found to vary depending on the formulation in which they were sulfidized. Our results suggest that the type of sulfide layer formed on the sulfidized brass cords is different in different compounds, depending on the individual compound formulation ingredients. Hence, the type of protection that the sulfide layer offers depends on the formulation. Generally, a higher loading of sulfur in the rubber formulation led to formation of a poor copper sulfide adhesion layer which performed worst under aging and corrosion testing environments. The cords in such cases were found to show corrosion cracking after corrosion testing. Resins along with normal sulfur loading did not show this effect. However, resins along with higher loading of sulfur were found to further deteriorate the corrosion performance of the copper sulfide adhesion layer. We are proposing that the copper sulfide is modified in terms of its crystal structure, which makes it protective in some cases and crack in other cases. Also, a correlation was found between the level of iron migration and the corresponding corrosion performance of the sulfidized tire cord using SIMS analysis on various sulfidized cords. The migration of iron was more pronounced in cases where high sulfur was used, which ultimately resulted in poor corrosion performance. A new mechanism for adhesion degradation of rubber to brass-plated steel cords is proposed based on these corrosion studies. It is proposed that the aging of the cord, which results in loss of rubber-to-brass bonding, is due to iron dissolution from the sulfidized tire cord. It is further discussed how this overall approach of testing the corrosion protection properties of the copper sulfide adhesion layer as a function of formulation ingredients might be useful to formulate newer formulations for better and durable adhesion performance in rubber-to-brass bonding in tires.     

SBS/LDPE共混型热塑性弹性体的性能研究(I)

选用热塑性丁苯橡胶(SBS)和低密度聚乙烯(LDPE)为主体材料,采用部分动态硫化法制备了一类性能良好的材料热塑性丁苯橡胶 低密度聚乙烯共混型热塑性弹性体,具有力学强度高,断裂伸长率大,可重复加工等特点,并研究了聚烯烃的品种、橡塑比、硫化体系等因素对动态硫化SBS LDPE热塑性弹性体力学性能的影响。     

TMPTMA在硅橡胶中的应用研究

研究了助交联剂三羟甲基丙烷三甲基丙烯酸酯(TMPTMA)对硅橡胶硫化性能、力学性能、低温性能和粘接性能的影响。结果表明,加入少量TMPTMA能改善硅橡胶的硫化特性和工艺性,提高硫化胶的硬度,降低硅橡胶的结晶温度,并有效提高硅橡胶与金属的粘接强度;但TMPTMA用量超过一定数值后,由于TMPTMA部分自聚合,在硅橡胶内形成一定的交联网络,造成两相界面粘接力变差,致使硅橡胶的拉伸强度降低。当TMPTMA用量为1份时,硅橡胶具有最佳的综合性能。     

环氧树脂对EPDM性能影响的研究

研究了环氧树脂用量对三元乙丙橡胶工艺性能和力学性能的影响,研究结果发现,环氧树脂对三元乙丙橡胶有增塑和增粘作用,影响了其硫化特性,并降低了三元乙丙橡胶硫化胶的力学强度.     

不同硫化体系对环保型硬丁腈橡胶性能的影响

以松香酸皂与油酸皂组成的复合乳化体系制备的中试产品丁腈橡胶(NBR)为基胶,分别用硫黄体系和过氧化物体系进行硫化,研究了NBR混炼胶的硫化特性和硫化胶的物理机械性能、耐老化性能、耐油及耐寒性能,并与传统产品NBR 3604进行了比较。结果表明,采用硫黄体系时,NBR混炼胶的硫化程度较浅,硫化速率较慢;采用过氧化物体系时,NBR混炼胶的硫化程度较深,硫化速率较快,NBR胶料宜采用过氧化物硫化体系进行硫化;2种硫化体系下制得NBR硫化胶的物理机械性能与NBR3604硫化胶相差不大,过氧化物硫化体系制得NBR硫化胶的耐老化性能较好;与NBR 3604硫化胶相比,2种硫化体系下制得NBR硫化胶的耐寒性稍好,耐油性稍差。     

NR/SBR并用胶配比对其硫化特性和力学性能的影响

考察了天然橡胶与丁苯橡胶不同配比对并用胶硫化特性和力学性能的影响.无转子硫化仪的测试结果表明,随着丁苯橡胶的占比增加,最小转矩和最大转矩均变大,且两者差值也随之增大,硫化时间延长,硫化胶的拉伸强度和撕裂强度明显下降,硬度增加;120℃老化后拉伸强度有不同程度的下降,天然橡胶占比越多下降越明显.     

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。     

Blends of polyacetal and ethylene-octene elastomer: Mechanical,dynamic mechanical and morphological properties

Polyacetal (POM) and ethylene octene copolymer(EOC) elastomers form immiscible blends with extremely low compatibility. In order to improve the dispersion, stability and properties of these blends, dynamic vulcanization was carried out in a twin screw extruder using dicumyl peroxide. The tensile strength decreased with increase in % elongation at break for both blend systems. There was a drastic decrease in impact strength for unvulcanized blends as the elastomer content increased and this was attributed to the coalescence of the elastomer particles as their content increased. In the case of dynamically vulcanized blends there was a significant increase in impact strength as the levels of elastomer increased. Dynamic mechanical analysis has been carried out to investigate the effect of blend composition and dynamic vulcanization on dynamic mechanical parameters such as storage modulus, loss modulus and loss factor. The results indicate gross incompatibility of POM and EOC blends. However, dynamically vulcanized blends show better adhesion between component polymers. The morphological studies reveal that the particle size and coalescence of elastomer was significantly reduced in comparison to unvulcanized bends. The phase adhesion was improved by dynamic vulcanization. Hence, it was observed that dynamic vulcanization effectively improves the morphology of the blend system and enhances the properties of polyacetal.     

增强三元乙丙橡胶粘合性能的研究

研究烷基酚醛树脂用量、硫化剂DCP/TAIC用量比、增塑剂用量以及硫化工艺对三元乙丙橡胶(EPDM)粘合性能的影响。结果表明:烷基酚醛树脂可提高EPDM与聚酯线绳的粘合性能;随硫化剂DCP/TAIC用量比增大,EPDM与聚酯线绳的粘合性能先提高后保持不变,用量比为9/1时综合性能最佳;EPDM与聚酯线绳的粘合性能随增塑剂2280用量增大几乎呈线性下降趋势;在充分硫化情况下,低温长时间硫化和高温快速硫化工艺对粘合性能影响不大,为提高生产效率,EPDM汽车多楔带可采用高温快速硫化工艺。     

Pre‐Vulcanization of Large and Small Natural Rubber Latex Particles: Film‐Forming Behavior and Mechanical Properties

The pre‐vulcanized large rubber particle (LRP) and small rubber particle (SRP) latices are independently prepared to investigate their film‐forming process and mechanical properties after being cast into films. The surface morphologies and roughness of both LRP and SRP films are found to be dependent on crosslink densities. The networks inside each rubber particle (RP) restrict particle deformation resulting in residual contour of RP within the film surface. For highly crosslinked RP, the collapse of the top surface of the RPs in the LRP films appears to create many “crater‐like” structures within the film surfaces, while they present only protruding particles within the SRP and blend films. This seems to indicate that LRPs are easier to coalesce and form film than SRPs. Additionally, dynamic and mechanical properties and strain‐induced crystallization (SIC) behaviors of the latex films, are effectively enhanced after pre‐vulcanization. The pre‐vulcanized LRP films perform better tensile properties and SIC than the SRP can.     

Influence of Cure Conditions on the Adhesion of Rubber Compound to Brass-plated Steel Cord. Part II. Cure Time

The effect of the cure time of a rubber compound on the adhesion with brass-plated steel cord was investigated. The formation, growth and degradation of the adhesion interphase formed between the rubber compound and brass-plated steel cord was also observed as well as the formation of a weak boundary layer in the rubber near the adhesion interphase. With increase in the cure time from a fourth to four times of t₉₀, the pull-out force after vulcanization increased significantly up to one-half of t₉₀ followed by a slight increase to t₉₀, and then decreased slowly with further increase in cure time. This decrease in pull-out force upon prolonged vulcanization may be explained by the severe degradation of rubber compound attached to the adhesion interphase. Also, upon prolonged vulcanization, the adhesion interphase with a rich ZnS layer may act as a barrier to copper diffusion which is required to form the adhesion interphase of copper sulfide. After thermal aging of the adhesion samples, the pull-out force decreased in comparison with that of the unaged. The decrease of pull-out force after thermal aging stemmed mainly from the decline of tensile properties after thermal aging. The adhesion after humidity aging was different from that after thermal aging. Upon increasing the cure time to one-half of t₉₀, the pull-out force increased. But a further increase in the cure time caused a decline in pull-out force. This phenomenon can be explained by the degradation of the adhesion interphase. At longer cure time, a severe growth of copper sulfide and a large amount of dezincification were observed in the adhesion interphase. At shorter cure time, a significant growth of copper sulfide in the adhesion interphase does not occur, whereas the formation a of a ZnS layer appeared after humidity aging. With increasing cure time, the formation of a weak boundary layer in the rubber near the adhesion interphase increased, resulting in the cohesive failure of the rubber layer. The proper formation of the adhesion interphase and the good physical properties of the rubber compound at optimum cure time can lead to the high retention of adhesion.