Characterization of the Aging Behavior of Microorganism Coagulated Natural Rubber

Abstract

The characterization of the aging behavior of raw natural rubber (NR) coagulated by microorganisms (NR-m) was performed on a rubber processing analyzer (RPA) by tests of frequency sweep, strain sweep and stress relaxation, respectively. With the prolongation of the aging time, the storage modulus (G'), storage torque (S'), complex viscosity (η*) and stress relaxation time of raw NR-m decreased while the damping factor (tanδ) were increased. As the oscillation frequency was increasing, the G' rose gradually but the tanδ decreased. The η*diminished over the whole range of frequency shear rate (γƒ) values. Its change remained all almost the same at low strain shear rate (γs) but began to decrease sharply when the rate reached a higher value. The S' soared up in the region of less than 10°, but began to slow down after that point.

Vulcanization Kinetics of Starch Xanthate /Natural Rubber Composite

“…The main techniques used to study the kinetics of rubber vulcanization include differential scanning calorimetry (DSC), oscillating disk rheometry (ODR), moving die rheometry (MDR) and RPA. The RPA is a new, condition-controlled shear cone-and-cone dynamic mechanical rheological tester specifically designed to measure the dynamic properties in a certain range of time, temperature, frequency and strain for polymers before and after curing [5,6]. In this paper, the vulcanization kinetic of SX/NR composite in range of induction period and curing period was analyzed with use of a RPA(MFR, Prescott UK).…”