顶空气相色谱-质谱联用分析橡胶硫化烟气成分来源

建立顶空气相色谱-质谱(HS-GC/MS)联用分析橡胶(制品)硫化烟气成分的方法。对选定配方原材料及其混炼胶在硫化温度下挥发的烟气成分进行HS-GC/MS测试,确定挥发分成分;通过对定性结果的分析对比,推断硫化烟气各成分的来源。该方法的建立对开发绿色橡胶制品有很好的参考性。     

Elucidation of segmental relaxations of silica-filled cis-polybutadiene rubber composites

There has been a lot of interest in characterizing polymer chain dynamics of rubber compounds because it is thought to underpin the exceptional mechanical properties of composites. We studied the effect of precipitated silica on segmental mobility of cis-polybutadiene rubber by using differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). It was found that the calorimetric glass and melting transitions of silica-filled master batch materials were essentially identical to those of the gum rubber, showing no dependence of silica loading and silane treatment. And, we observed in calorimetric measurement a change in the melting transition step for the vulcanizates. The results were correlated to the change of chemical crosslinks caused by various factors filler agglomeration and adsorption effect that tended to decrease chemical crosslink density and silane modification increased it. The DMA results demonstrated that the second peak in loss modulus versus temperature curve for the quenched vulcanizates was assigned to melting peak, and this peak disappeared at a slow cooling rate, which coincided well with DSC results. Moreover, crystalline parts constrained amorphous regions such that the glass transition temperature was raised for the cooled vulcanizates with high chemical crosslinks.     

新型偶联剂Si747对白炭黑填充溶聚丁苯橡胶/顺丁橡胶并用胶加工性能及动态性能的影响

对比传统偶联剂Si69,研究新型偶联剂Si747对白炭黑填充溶聚丁苯橡胶/顺丁橡胶并用胶加工性能及动态性能的影响。结果表明:与偶联剂Si69混炼胶相比,偶联剂Si747混炼胶的门尼粘度增大,门尼焦烧时间及正硫化时间缩短;随着偶联剂Si747用量增大,混炼胶的焦烧时间及正硫化时间缩短,加工安全性降低;在口模长径比为15、直径为1.5 mm、挤出温度为100℃的条件下,偶联剂Si747混炼胶挤出胶条的表面较平滑,离模膨胀率较小;偶联剂Si747硫化胶的生热及滞后损失较偶联剂Si69硫化胶明显降低。     

炭黑和白炭黑填充硫化胶的湿摩擦差异性分析

研究不同负荷和速度下炭黑和白炭黑填充硫化胶的湿摩擦因数,并对其摩损表面进行了扫描电子显微镜和透射电镜表征。结果表明：炭黑填充硫化胶的湿摩擦因数随着速度的增大呈线性下降,随着负荷的增大略有降低,而白炭黑填充硫化胶的湿摩擦因数随着速度的增大呈非线性下降,随着负荷的增大先迅速下降后缓慢降低;白炭黑填充硫化胶摩擦面橡胶膜较薄,裸露白炭黑粒子,过渡区摩擦力较大,不能忽略;炭黑填充硫化胶表面的橡胶膜厚度较大,表面炭黑粒子被橡胶大分子覆盖,过渡区摩擦力小,可以忽略。     

Silica masterbatches produced with liquid phase mixing Part IV. Volume variation and SEM observations upon stretching

The volume of vulcanizates changes slightly during stretching. Generally, dilatometry and hydrostatic weighing methods are used to measure volume change. Vacuole formation and polymer crystallization are the two main causes of the volume changes, and these are attributed to the separation of polymer from the filler surface and the alignment of polymer molecules, respectively. The relative volume change, ΔV/V, of four different vulcanizates based on a blend of SSBR (solution polymerized styrene-butadiene rubber) and BR (cis-polybutadiene rubber) has been plotted against elongation, ε. The relative volume change of an eco-visco-elastomer-composite (EVEC) compound produced by a continuous liquid phase mixing process was much less than that of a dry-mixed counterpart, especially after normalizing by stress, σ. Scanning electron microscopy (SEM) was utilized to observe the emergence of vacuoles during stretching, and obtain information on their relative size and distribution without the need for replication or ion sputter coating. SEM images also showed that the dispersion of silica in EVEC is better and the number of vacuoles is much less than in the dry-mixed compounds, characterizing a “denser” vulcanizate.     

防老剂对过氧化物硫化体系氢化丁腈橡胶性能的影响

研究防老剂对过氧化物硫化体系氢化丁腈橡胶(HNBR)性能的影响。结果表明:防老剂种类可以显著影响过氧化物硫化体系HNBR硫化胶的交联密度,防老剂ZMTI可显著消耗过氧化物自由基,阻碍过氧化物硫化反应的进行,使采用防老剂ZMTI的硫化胶的交联密度减小,单用防老剂445或ODA对硫化胶的交联密度影响相对较小;单用防老剂445的HNBR硫化胶的定伸应力最大,弹性最好,压缩永久变形和损耗因子最小,防老剂445是非常适合过氧化物硫化体系HNBR的防老剂。