Elastomer processing and application of rheological fundamentals

Abstract

SynopsisElastomer processing operations are discussed and classified as unit operations. The theory of nonlinear viscoelasticity is applied to processing unvulcanized amorphous rubber and the significance of the maximum relaxation time T,,, is emphasized.

Rheological Behavior of Unvulcanized Rubber

“…Weissenberg suggested that the recoverable elastic strain represents fluid elasticity in the same way that the Reynolds number represents inertia. White [298], Slattery [262], White and Tokita [299,310], and Metzner et al [186,187] have published analyses that have brought these ideas together into a formal scheme. Reiner [242] later suggested that the basic dimensionless group correlating viscoelastic phenomena was a "Deborah number" which may be represented as a ratio of the characteristic relaxation time i ch of the deforming material to the duration / of the deformation.…”

“…White and Tokita [282,299,300,[308][309][310]312] and Ninomiya et al [212,213] have carried out research programs in which various processing characteristics were interpreted in terms of the theory of viscoelasticity. White and Tokita [282,299,300,[308][309][310]312] and Ninomiya et al [212,213] have carried out research programs in which various processing characteristics were interpreted in terms of the theory of viscoelasticity.…”

Nonisothermal nip flow in calendering operations

“…Perturbation around the first-order solution (Walters, 1972;Davies and Walters, 1972) provides insight in the problem but is not amenable to extrapolation for strongly nonlinear fluids. Dimensional analysis could eventually be used if sufficient insight and data were available (Tokita and White, 1966;White and Tokita, 1967;Chong, 1968). Petrusanskij et al (1971) seem to have been the first to tackle the nonisothermal case.…”

Rheology of Short Nylon-6 Fiber Reinforced Styrene-Butadiene Rubber

“…The need for rheological studies and their importance in the selection of processing conditions were pointed out by Brydson [9]. White and Tokita established a correlation between rheology and processing [10][11][12]. Crowson et al reported the rheology of short glass fiber reinforced thermoplastics and found that fibers orient along the flow direction in the convergent flow and perpendicular to the flow direction in the divergent flow [13][14].…”