화학공학소재연구정보센터
홈 로그인 로그아웃 연락처 사이트맵
Macromolecular Research, Vol.16, No.6, 561-566, August, 2008
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Influence of the Cure Systems on Long Time Thermal Aging Behaviors of NR Composites
Sung-Seen Choi†, Jong-Chul Kim, Seung Goo Lee1, †, and Yong L. Joo2
  • Department of Chemistry, Sejong University, Seoul 143-747, Korea
  • 1BK21 FTIT, Department of Advanced Organic Materials & Textile System Engineering, Chungnam National University, Daejeon 305-764, Korea
  • 2School of Chemical & Biomolecular Engineering, Cornell University, Ithaca, NY 14850, USA
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NR composites with different curing systems were aged thermally at 60, 70, 80, and 90 ℃ for 2-185 days in a convection oven, and the changes in the crosslink density were investigated as a function of the accelerated thermal aging. The overall crosslink densities increased with increasing aging time irrespective of the aging temperatures and curing systems. The changes in crosslink density were enhanced by increasing the aging temperature. The degree of the increased crosslink density was in the following order: “the conventional cure system > the semi-EV system > the EV system”. For short term thermal aging, the change in crosslink density with the aging time was complicated, particularly for low temperature aging. The activation energies of the change in crosslink density with thermal aging using the conventional and semi-EV cure systems increased and then remained relatively constant with increasing aging time, whereas that of the specimen with an EV cure system tended to increase linearly. The experimental results were explained by the dissociation of the existing polysulfidic linkages and the formation of new crosslinks through the crosslinking-related chemicals remaining in the sample.
Keywords:thermal aging;NR composites;cure systems;crosslink density change;activation energy change
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