Mechanical properties and crosslink density of rare earth-modified high-abrasion furnace-filled powdered natural rubber

摘要

High-abrasion furnace-filled powdered natural rubber [P(NR/HAF)] has more advantages than traditional HAF-filled bale NR (NR/HAF) because of its better environmental performance and easier processing quality, but its lower mechanical properties are disadvantageous. To improve the mechanical properties, rare earth-modified HAF-filled powdered NR [P(NR/HAF-Ln)] (Ln = Sm,La,Pr) was prepared by means of coacervation-coprecipitation, using rare earth-modified HAF as separant and filler. The effect on mechanical properties of P(NR/HAF-Ln) vulcanizate exerted by the emulsifier/HAF ratio, powdering temperature, Ln/HAF ratio and type of Ln, and HAF content were studied. The results indicated that when optimum formulation, the mechanical properties of P(NR/HAF-Ln) vulcanizate were better than P(NR/HAF) vulcanizate. In addition, the relationship of the apparent crosslink density and HAF content of P(NR/HAF-Ln), P(NR/HAF), NR/ HAF vulcanizates was also investigated, along with their SEM microphotographs of tensile fracture surface, which indicated that the excellent mechanical properties of P(NR/ HAF-Ln) vulcanizate was attributed to correct amount of Ln that could increase crosslink density and reinforce the interface structure of NR matrix/HAF-Ln particle. (c) 2006 Wiley Periodicals, Inc.