Technical Paper Archive


This site contains all papers presented at Rubber Division, ACS Technical Meetings from 2000-2018. Meetings prior to 2000 are incomplete and papers are added as they are digitized.


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EFFECT OF PARTICLE SIZE ON ULTRASONIC DEVULCANIZATION OF TIRE RUBBER IN TWIN-SCREW

35

Event: 182nd Technical Meeting
Location: Cincinnati, OH
Date: October 09, 2012
Author: Avraam I. Isayev, Tian Liang* and Todd M. Lewis
Paper Number: 35

Price: $20.00

  • The die pressure and ultrasonic power consumption during devulcanization were recorded. Degree of devulcanization was investigated by measuring the crosslink density, gel fraction and revulcanization behavior. Rubber of 30 mesh exhibited a lower die pressure and higher degree of devulcanization than those of rubber of 10 mesh. Due to the higher level of devulcanization and lower viscosity of devulcanized rubbers at higher amplitudes, the temperature of devulcanized rubbers at the die was reduced with an increase of the ultrasonic amplitude. Generally, the torque at the start of curing and maximum torque on curing curve measured during revulcanization is higher for rubber of 10 mesh and rubbers devulcanized at a lower temperature. Rheological properties of devulcanized and revulcanized rubbers and mechanical properties of revulcanizates were measured. The complex viscosity of devulcanized and revulcanized rubbers of both meshes as a function of frequency exhibited a power-law behavior with the power-law index being 0.06 for devulcanized rubbers and 0.02 for revulcanized rubbers. The consistency index of devulcanized and revulcanized rubbers was higher for rubber of 10 mesh, however, both rubbers showed a higher consistency index at a lower temperature. Cole-Cole plots, crosslink density and gel fraction of devulcanized and revulcanized rubbers, revulcanization behavior, and modulus of revulcanizates separated in two distinct groups based on the level of devulcanization and effect on molecular structure of devulcanized rubber. Revulcanizates with a greater degree of devulcanization exhibited higher elongation at break, while those with a lower degree of devulcanization exhibited higher strength and modulus. Revulcanizates of rubber of 30 mesh exhibited a consistently higher elongation at break. The normalized gel fraction Versus normalized crosslink density was described by a unique function independent of the processing conditions and rubber particle size.

    Papers from 182nd Technical Meeting

    Items from 182nd Technical Meeting