Uthai Thepsuwan

Properties of Natural Rubber Reinforced by Carbon Black-based Hybrid Fillers

Properties of natural rubber (NR) filled with hybrid fillers were compared. Loading of the primary filler, carbon black (CB), was fixed whereas that of the secondary fillers, carbon nanotube (CNT) and conductive carbon black (CCB), was varied. The increase of secondary filler loading results in loss of elasticity but the increases of viscosity, vulcanization rate, cross-link density, hardness, modulus, thermal and electrical conductivities and tan δ. Obviously, CNT gives stronger effect than CCB. However, CCB gives improvement in tensile and tear strengths when added up to 3 phr whereas the addition of CNT shows no significant effect on the strengths.

Effects of Blend Ratio and SBR Type on Properties of Carbon Black-Filled and Silica-Filled SBR/BR Tire Tread Compounds

This work aimed at investigating the effects of blend ratio between styrene butadiene rubber (SBR) and butadiene rubber (BR) and SBR type (E-SBR and S-SBR) on properties of SBR/BR tire tread compounds. Influences of these parameters on properties of the tread compounds reinforced by 80 parts per hundred rubber (phr) of carbon black (CB) and silica were also compared. Results reveal that hardness, strengths, and wet grip efficiency were impaired whereas rolling resistance was improved with increasing BR proportion. Surprisingly, the presence of BR imparted poorer abrasion resistance in most systems, except for the CB-filled E-SBR system in which an enhanced abrasion resistance was observed. Obviously, S-SBR gave superior properties (tire performance) compared to E-SBR, particularly obvious in the silica-filled system. Compared with CB, silica gave comparable strengths, better wet grip efficiency, and lower rolling resistance. Carbon black, however, offered greater abrasion resistance than silica.

Property modification of chloroprene rubber by addition of ultra-fine acrylic rubber powder

Abstract The role of ultra-fine pre-vulcanised acrylic rubber powder (ACMP) in properties of chloroprene rubber (CR) was studied. ACMP was incorporated into CR at various loadings and the properties of the ACMP filled CR were investigated. Owing to the high thermoplastic nature of the ACMP, better processability is obtained with increasing ACMP loading. Even though the presence of ACMP gives negative effect on cure rate and state of cure, both modulus and hardness of the vulcanisates increase continuously with increasing ACMP loading. The tensile strength is also improved with increasing ACMP loading up to 20 phr. Nevertheless, elasticity and abrasion resistance of the vulcanisates are impaired as the concentration of ACMP is increased. This is mainly attributed to the combination of dilution effect and reduced crosslink density. Since ACMP is fully saturated and highly polar, the incorporation of ACMP into CR gives rise to enhanced aging and oil resistance of the vulcanisates.