Effect of Acetylated SEBS/PP for Potential HVAC Cable Insulation

Thermodynamic Parameters of Crosslinked Elastomers (BR, SBR and NBR) and Their Blends

Herein, a methodology is employed based on the Flory-Rehner equation for estimating the Flory-Huggins interaction parameter (χ12*) of crosslinked elastomer blends. For this purpose, binary elastomer blends containing polybutadiene rubber (BR), styrene-butadiene rubber (SBR) and nitrile-butadiene rubber (NBR), were prepared in a mixing chamber at a temperature below the activation of the crosslinking agent. Swelling tests with benzene were employed to determine the crosslinked fraction, finding that after 20 min of thermal annealing, the BR and NBR were almost completely crosslinked, while the SBR only reached 60%. Additionally, the BR-SBR blend increased by 2-3 times its volume than its pure components; this could be explained based on the crosslink density. From the mechanical tests, a negative deviation from the rule of mixtures was observed, which suggested that the crosslinking was preferably carried out in the phases and not at the interface. Furthermore, tensile tests and swelling fraction (ϕsw) results were employed to determine the average molecular weight between two crosslinking points (Mc), and subsequently χ12*. Calculated χ12* values were slightly higher than those reported in the literature. The calculated thermodynamic parameters for the blends showed positive ΔGmix values and endothermic behavior, suggesting their immiscible nature.

Mechanism and Influence Factors of Abrasion Resistance of High-Flow Grade SEBS/PP Blended Thermoplastic Elastomer

Hydrogenated styrene-butadiene-styrene block copolymer (SEBS)/polypropylene (PP) blended thermoplastic elastomer (TPE) is suitable for preparing the automotive interiors because of its excellent elasticity, softness, weather resistance, low odor, low VOC and other environmental-friendly properties. The skin of the automobile instrument panel is an appearance part, which requires excellent friction loss resistance of surface. In this paper, the high-flow SEBS/PP blended thermoplastic elastomer (TPE) suitable for the preparation of injection molding skins for automobile instrument panel was studied. By comparing the Taber abrasion and cross-scratch properties, the effects of SEBS's molecular weight, styrene content in the molecule, molecular structure and types of lubricating agents on the friction loss properties of the material were investigated. The results show that under the same SEBS molecular structure, the higher the molecular weight within a certain range, the better the wear resistance of high-flow SEBS/PP type TPE, but the ultra-high molecular weight exhibits lower wear resistance than high molecular weight; The high-flow SEBS/PP blended TPE prepared by medium styrene content SEBS has better abrasion resistance; TPE prepared by star SEBS is better than linear SEBS; Adding silane-based lubricating agents is beneficial to improve the friction loss resistance of the material, especially combined use of high and low molecular weight silicone.