Evaluation of the properties of Perlite/EPDM Rubber

Abstract

The effect of perlite was investigated on rheological, mechanical and flammability properties of EPDM rubbers with
different perlite ratio. Perlite was added to EPDM rubber at 11.5, 24.5 and 55 phr ratios. The EPDM rubbers were
compounded using a laboratory-scale Banbury mixer and subsequently vulcanized under pressure to produce standardized
test plates. Rheological properties of EPDM rubber were examined by rheometer test before pressing. The tensile test,
permanent deformation test, abrasion test and hardness tests were performed to determine the mechanical properties. The
flammability characteristics of perlite-filled EPDM rubber were assessed using the UL-94 HB flammability test. As a result
of study, minimum torque (ML) and maximum torque (MH) increased with increasing perlite content. The hardness of
EPDM/20K rubber, initially measured at 58 Shore A, increased by 7.9% with the addition of 22phr perlite, reaching a value
of 63 Shore A. The incorporation of 55 phr perlite into EPDM/20K rubber resulted in a 30.6% reduction in tensile strength
compared to the unfilled EPDM/20K formulation. Additionally, the elongation at break values decreased (7.48%) with
increasing perlite content. A similar trend was observed for compression set and abrasive wear, both of which increased
(37.79% and 9.69%, respectively) as the perlite concentration was elevated. The electric current value of EPDM/20K rubber,
which was 1.999mA, decreased to 0.025-0.441mA with the addition of perlite. Different ratios of perlite added to
EPDM/20K rubber decreased the burning rate, while the lowest burning rate was obtained in EPDM/20K/11.5P rubber.