Effect of plasticizer and curing system on freezing resistance of rubbers

Abstract

At glass transition temperature, T g the rubber compound becomes stiff and brittle and it loses all its rubbery characteristics. This article deals with the changes in T g of rubber blends based on natural rubber and polybutadiene rubber of varying vinyl content having different types and content of plasticizers, different curing systems and its effect on physico-mechanical properties to improve its freezing resistance. The plasticizers used were dioctylphthalate (DOP), tricrecylphosphate (TCP), dioctyladipate (DOA), and oil type plasticizers like parafinic oil (P#2) and aromatic oil (A#2). Among the plasticizers, when DOP and DOA content was high, an appreciable decrease of T g was found compared to TCP. Moreover, there was a remarkable decrease of T g using DOA plasticizer, which shows more effective on freezing resistance. However, there was not much change in T g with oil-type plasticizers with high oil content compared to TCP plasticizer. The effect of cross-linking systems such as conventional sulfur vulcanization (CV), efficient sulfur vulcanization (EV), and dicumyl peroxide (DCP) and rubber blends with varying vinyl content in polybutadiene rubber were also carried out. It was found that T g in different cross-linking system decreased in this order: CV < EV < DCP. It reveals that DCP cross-linking system affect more for improving freezing resistance. Physico-mechanical properties such as tensile strength, tear strength, hardness were also measured. The ratio of initial slope (M 0 ) to steady-state slope (M 1 ), M 0 /M 1 in tensile curves of different blends were verified, which in turn related to the physico-mechanical properties and freezing resistance of rubber compounds. V C 2013 J. Appl. Polym. Sci. 2014, 131, 39795.

The Effect of Polyurethane Glycolysate on the Structure and Properties of Natural Rubber/Carbon Black Composites

“…In some applications (when the working temperature of elastomer part is relatively low) the addition of plasticizer is connected with the decreasing of glass transition temperature, which permit to extend the working temperature range [1][2][3]. Oh and co-workers investigated the influence of selected plasticizers [i.e.…”

Oil resistance and low‐temperature characteristics of plasticized nitrile butadiene rubber compounds

“…The T g value obtained by DSC experiments is related to segmental chain motion, and it represents the temperature above which the material changes from a stiff solid to a viscous fluid or a rubbery substance. The gehman torsion test provides the relative stiffness at low temperatures as compared with the stiffness at room temperature, and the TR test indicates the elastic recovery at low temperatures …”

Combination of Phosphorous Flame Retardants and Aluminum Trihydrate in Multicomponent EPDM Composites

“…The rubbers containing TOF, R-2, R-1/2, and R-1/2P, exhibited lower minimum torque (M L ) compared to R. All the other flame retarded rubbers showed higher values for M L , due to the reinforcing effect of the solid fillers APP, PANI, and ATH. Rubbers with higher filler loading and reinforcing fillers showed higher values for M L [40,41]. Table 2 presents the maximum torque (M H ), which is a measurement stock modulus [41].…”

“…M H -M L was used to assess the crosslink density of the EPDM rubbers qualitatively [40]. The results showed that the percentages of the M H -M L values decreased with reduced network density, because of increased slippage between the polymer chains.…”