Lindemann Niclas, Schawe Jürgen E K, Lacayo-Pineda Jorge
Institut für Physikalische Chemie und Elektrochemie, Leibniz Universität Hannover, Callinstraße 3A, 30167 Hanover, Germany.
Continental Reifen Deutschland GmbH, Jädekamp 30, 30419 Hanover, Germany.
Polymers (Basel). 2022 Jun 28;14(13):2626. doi: 10.3390/polym14132626.
Resins are important for enhancing both the processability and performance of rubber. Their efficient utilization requires knowledge about their influence on the dynamic glass transition and their miscibility behavior in the specific rubber compound. The resins investigated, poly-(α-methylstyrene) (AMS) and indene-coumarone (IC), differ in molecular rigidity but have a similar aromaticity degree and glass transition temperature. Transmission electron microscopy (TEM) investigations show an accumulation of IC around the silanized silica in styrene-butadiene rubber (SBR) at high contents, while AMS does not show this effect. This higher affinity between IC and the silica surface leads to an increased compactness of the filler network, as determined by dynamic mechanical analysis (DMA). The influence of the resin content on the glass transition of the rubber compounds is evaluated in the sense of the Gordon-Taylor equation and suggests a rigid amorphous fraction for the accumulated IC. Broadband dielectric spectroscopy (BDS) and fast differential scanning calorimetry (FDSC) are applied for the characterization of the dielectric and thermal relaxations as well as for the corresponding vitrification kinetics. The cooling rate dependence of the vitrification process is combined with the thermal and dielectric relaxation time by one single Vogel-Fulcher-Tammann-Hesse equation, showing an increased fragility of the rubber containing AMS.
树脂对于提高橡胶的加工性能和性能都很重要。它们的有效利用需要了解它们对动态玻璃化转变的影响以及它们在特定橡胶配方中的混溶行为。所研究的树脂，聚（α-甲基苯乙烯）（AMS）和茚-香豆酮（IC），在分子刚性上有所不同，但具有相似的芳香度和玻璃化转变温度。透射电子显微镜（TEM）研究表明，在高含量下，IC 在丁苯橡胶（SBR）中硅烷化二氧化硅周围积累，而 AMS 没有这种效果。如动态力学分析（DMA）所确定的，IC 与二氧化硅表面之间这种更高的亲和力导致填料网络的致密性增加。从戈登-泰勒方程的角度评估了树脂含量对橡胶配方玻璃化转变的影响，并表明积累的 IC 存在刚性无定形部分。应用宽带介电谱（BDS）和快速差示扫描量热法（FDSC）来表征介电和热弛豫以及相应的玻璃化动力学。玻璃化过程的冷却速率依赖性通过一个单一的沃格尔-富尔彻-塔曼-黑塞方程与热弛豫时间和介电弛豫时间相结合，表明含 AMS 的橡胶的脆性增加。
