Compression aging and lifetime assessment of foamed silicone rubber for sealing

doi:10.19491/j.issn.1001-9278.2023.12.009

Abstract

Abstract:

A compression thermal aging method was employed to accelerate the aging of foamed silicone rubber for sealing at 180 ºC over different time. The tearing performance， mass loss rate， microstructure and infrared spectroscopy of the aged rubber samples were analyzed， and their lifetime was evaluated by using compression rebound rate as an important parameter. The results indicated that the foamed silicone rubber exhibited a slight increase in the tear strength with an increase in aging time （within 36 h）， followed by a decrease after aging for over 72 h. With a continuous increase in the aging time， there is a gradual increase in the mass loss rate of the foamed silicone rubber from 0 to 5.5 wt% within 144 h. The infrared spectroscopic analysis indicated that the main and side chains on the surface molecular chain of the foamed silicone rubber were broken after thermal aging at 180 ℃. However， its main chains in the internal part were mainly cross⁃linked， but its side chains were mainly broken. The morphological observation indicated that there were cracks and pores appearing on the surface of the foamed silicone rubber with an increase in aging time， whereas the internal pores decreased gradually from a large size to the small one. The service lifetime of the foamed silicone rubber material was evaluated by using experimental data on the compression aging rebound rate. The results showed that the service lifetimes were 15.65， 7.01， and 5.11 years at 23， 35， and 40 ℃， respectively.

Key words: foamed silicone rubber, compression aging, compression rebound rate, life assessment

CLC Number:

TQ333.93

WEI Chiyuan, XIE Jingjing, SHI Peixin, GAO Qianhong, LI Haixia. Compression aging and lifetime assessment of foamed silicone rubber for sealing[J]. China Plastics, 2023, 37(12): 54-59.

Figures/Tables 9

Fig.1. Tear strength against aging time

Fig.2. Weight loss against aging time

Fig.3. Infrared spectra of the samples for different aging times

Fig.4. Surface micromorphology of samples for different aging times

Fig.5. Cross section microscopic morphology of the samples for different aging time

Fig.6. Degradation mechanism of silicone rubber molecular chain

Fig.7. Rebound rate of the samples at different temperature for various aging time

Fig.8. Linear relationship between logτ and（1/T）

温度/℃	预测寿命/年
23	15.65
35	7.01
40	5.11

Tab.1. Predicted lifetime at different temperatures

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