Improvement of properties of silica-filled natural rubber compounds using polychloroprene

Because silica has strong filler-filler interactions, a silica-filled rubber compound is characterized by a poor dispersion of the filler. Properties of silica-filled natural rubber (NR) compounds were improved using polychloroprene (chloroprene rubber [CRI). The bound rubber content of the compound increases and the filler dispersion is also improved by adding CR to the compound. Physical properties such as modulus, tensile strength, abrasion, and crack resistance are improved by adding CR. Elongation at break of the vulcanizates containing CR is longer than that of the vulcanizate without CR, although crosslink density of the former is higher than that of the latter. The improved physical properties are attributed to the good dispersion of silica by adding CR. (C) 2002 John Wiley Sons, Inc.