Page 83 - 《橡塑技术与装备》英文版2026年1月

TEST AND ANALYSIS

Many scholars have conducted research on its aging properties Kechuang Rubber & Plastics Machinery Equipment Co., Ltd.;
. The rubber industry heavily relies on accelerated aging XK-160 type two-roll open mill, product of Shanghai Shuangyi
measurements, especially thermal aging, as quality assurance Rubber & Plastics Machinery Co., Ltd.; MV2000 type Mooney
tests and specifications. Gao Yue from Shenyang University viscometer and MDR3000 type curing press, products of
of Technology briefly mentioned using compression heat Alpha Technology Co., Ltd. of the United States; XLB-D
generation to predict the service life of rubber. However, 600×600 type flat vulcanizing press, product of Zhejiang
compression heat generation testing is cumbersome and the Huzhou Dongfang Machinery Co., Ltd.; AI-3000 type rubber
cycle is long. To ensure product performance and guide product tensile testing machine, product of High-Speed Rail Testing
development, proposing a simple aging model to predict its Instrument (Dongguan) Co., Ltd.
lifespan is of great significance. 1.4 Sample preparation
The process by which raw rubber, vulcanized rubber, The mixing of rubber compound is carried out in two
and rubber products undergo damage to their composition and stages. The first stage is conducted in a mixer, with the mixing
structure due to the combined effects of internal and external process as follows: mix raw rubber for 30 seconds, add 2/3 of
factors during storage, transportation, processing, and use, the carbon black, mix for 40 seconds, add the remaining 1/3
resulting in a gradual loss of their original excellent properties of the carbon black and small materials, mix for 50 seconds,
and even their loss of use value, is called aging. The aging clean, add oil, and discharge the rubber compound when
process is divided into physical aging and chemical aging the cumulative time reaches 205 seconds. The second stage
based on whether the reactions and changes are reversible. is conducted on an open mill, with the mixing process as
Generally, rubber aging refers to irreversible chemical aging, follows: mix the first stage rubber compound for 35 seconds,
which is an inherent characteristic of rubber materials and one add a vulcanizing accelerator, mix for 45 seconds, clean, and
of the important reasons for rubber failure. This article studies discharge the sheet when the cumulative time reaches 90
the changes in the tensile properties of two types of EPDM seconds. After being placed at room temperature for 8 hours,
rubber, which are vulcanized with sulfur and peroxide, after the sample is prepared for vulcanization.
different aging times at different aging temperatures. A linear 1.5 Performance testing
regression equation is derived for the change in fractional The performance testing of rubber compound is
strain energy with aging time, and the aging rate constants conducted in accordance with the corresponding national
at different temperatures are determined. Furthermore, the standards. Reference is made to the evaluation method for
reaction activation energy is calculated, and a simple empirical ethylene-propylene-diene rubber (EPDM) specified in GB/
model is established to predict the lifespan of the product under T42268-2022. The Mooney viscosity test is conducted in
use and storage conditions, guiding its practical application. accordance with the provisions of GB 1232 standard, and
the Mooney viscosity is expressed as M L (1+4) at 125℃. The
1 Experimental part tensile strength and elongation at break properties are tested
1.1 Main raw materials using a universal material testing machine, with samples cut
EPDM3250, sourced from Lanxess, Germany. according to Type I specifications in the national standard GB/
Antioxidants, vulcanizing agents, sulfur, DCP, stearic acid, T 528-2009.
zinc oxide, co-crosslinking agents, paraffin wax, carbon black, 1.6 Aging test
and other additives are all commercially available. After cutting the vulcanized rubber sheet into Type I
1.2 Product formula dumbbell-shaped test specimens (115 mm×6 mm×2 mm)
#
#
1 refers to sulfur-cured EPDM rubber; 2 refers to according to the standard GB/T528-2009, hang it freely in a
peroxide-cured EPDM rubber. hot air aging oven. After aging at the specified temperature and
1.3 Main instruments and equipment time, remove it and let it stand at the standard test temperature
XSM-1/lO-120 type internal mixer, product of Shanghai (23±1) ℃ for 24 hours. Then, conduct the tensile property test

Vol.52，2026 ·37·