Zno and stearic acid

NR (Standard Vietnamese Rubber SVR-10, dirty content = 0.1 wt%, Astlett Rubber Inc., Oakville, ON, Canada), ENR-25, and ENR-50 (Epoxyprene 25, Epoxyprene 50, Muang Mai Guthrie Public Co., Ltd., Muang, Phucket, Thailand) were used as base rubbers. Silica (Ultrasil 7000 GR, Evonik Industries AG, Essen, Germany) with a Brunauer–Emmett–Teller (BET) surface area of 160 to 175 m²/g was used as a filler. Bis-[3-(triethoxysilyl)propyl]-tetrasulfide (TESPT, Si-69, Evonik Korea Ltd., Seoul, Korea) was used as the silane coupling agent. ZnO and stearic acid (Sigma-Aldrich Corp., Seoul, Korea) were used as activators, and N-(1,3-dimethyl butyl)-N-phenyl-p-phenylenediamine (6PPD, Kumho Petrochemical Co., Daejeon, Korea) was used as the antioxidant. Sulfur (Daejung Chemicals and Metals Co., Siheung, Korea) was used as the crosslinking agent. N-cyclohexyl benzothiazyl-2-sulfenamide (CBS, 98%, Tokyo Chemical Industry Co., Ltd., Tokyo, Japan) and 1,3-diphenylguanidine (DPG, 98%, Tokyo Chemical Industry Co., Ltd., Tokyo, Japan) were used as cure accelerators. N-cyclohexylthio phthalimide (PVI, Shandong Yanggu Huatai Chemical Co., Ltd., Liaocheng, China) was used as the pre-vulcanization inhibitor.

NR (Standard Vietnamese Rubber SVR-10, dirt content = 0.1 wt%; Astlett Rubber Inc., Oakville, ON, Canada) was used as the base rubber. Silica (Ultrasil 7000 GR, Evonik Industries AG, Essen, Germany), with a Brunauer–Emmett–Teller surface area of 160–175 m²/g, was used as the filler. Bis [3-(triethoxysilyl)propyl]-tetrasulfide (TESPT, Si-69; Evonik Korea Ltd., Seoul, Korea) was used as the silane coupling agent. ZnO and stearic acid (Sigma–Aldrich Corp., Seoul, Korea) were used as activators, and N-(1,3-dimethyl butyl)-N-phenyl-p-phenylenediamine (6PPD, Kumho Petrochemical Co., Daejeon, Korea) was used as the antioxidant. Sulfur (Daejung Chemicals and Metals Co., Siheung, Korea) was used as the crosslinking agent. N-cyclohexylbenzothiazyl-2-sulfenamide (CBS; 98%, Tokyo Chemical Industry Co., Ltd., Tokyo, Japan) and 1,3-diphenylguanidine (DPG; 98%, Tokyo Chemical Industry Co., Ltd., Tokyo, Japan) were used as the curing accelerators. N-(cyclohexylthio)phthalimide (PVI, Shandong Yanggu Huatai Chemical Co., Ltd., Liaocheng, China) was used as the prevulcanization inhibitor.