Study of Physical Properties for Vinyl Acetate Copolymer with Microcapsule Foaming Agent

• Main Authors: Ming-Ju Kuo, 郭名助
• Other Authors: 吳震裕
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/ej8bec

碩士 === 國立中興大學 === 化學工程學系所 === 107 === This study explores the foaming properties of EVA copolymer materials by the combination of using the original ADCA azo dimethyl hydrazine C2H4N402 foaming agent and the microcapsule foaming agent. Keeping the hard density does constant, efforts were made to enhance the rigidity between the foaming pores, improve the shock absorption and higher buffering capacity of the foam material to protect human movement or collision and reduce different sports injuries. Therefore, under the same system, in different doser of microcapsule foaming agent were added to the study, and the structure, physical properties and energy absorption of the foaming materials were evaluated by vulcanization test, SEM observation, physical testing, simulations helmet test (EN1077, EN1078, NOCSAE). In research (I), the microcapsule foaming agent was added in EVA copolymer, it was found that the EVA copolymer added with the microcapsule foaming agent without ADCA foaming agent had a vulcanization time (TC90) of 9.07 min in the vulcanization test at the addition ratio of only 3 phr and MAX foaming pressure was 266.74 lbf/in. Minimum curing time and MAX foaming pressure are obtained for 3 phr dosage in the three test formulations. For this foaming ratio, the microcapsule expansion agent is insufficient due to insufficient foaming power of microcapsule foaming agent. The cell structure of EVA copolymer was opened and the final expansion ratio was only 1.1 times. For the EVA copolymer with 3 phr microcapsule foaming agent and 3 phr ADCA foaming agents added, the vulcanization time (TC90) was 10.71 min and the MAX foaming pressure was 476.28 lbf/in. Increasing obvious vulcanization time will increase MAX foaming pressure . In the physical property test, the rebound was 11% and compressive strength was 1.2 kg/cm² that are better but compression deformation of 8.73% is worse. Shrinkage test at 70 ° C for 24 hours period for -2 cm X -2 cm X 0.37 mm specimen, shrinkage gave the relatively good value. In the impact test, impact strength was measured as 15.09 KN and the shock absorption strength was also better . In research (II), the microcapsule foaming agent was added in an amount of 3, 5, 7, 10 phr and 3phr ADCA foaming agent was added in the EVA copolymer. In the vulcanization test, the vulcanization time (TC90) was 11.56 min~12.48 min and the foaming pressure was 562.61 lbf/in〜630.9 lbf/in . In the physical property test, the rebound was 11.5 %〜11.9 % and compression strength was 1.20 kg/cm² to 1.24 kg/cm² that are better, but the compression deformation is worse. Shrinkage gave the relatively good value in the 24 hour shrinkage test at 70 ° C. The shock absorption strength also appears a linear mode in the impact test, since the increase in the addition of microcapsule foaming agent is not much, the data change is small. The impact height was 910 mm, microcapsule foaming agent was added in an amount of 3, 5, 7, 10 phr, impact strength was measured as 15.09 KN, 13.59 KN, 13.37 KN, 11.54 KN. The impact height was 1526mm, microcapsule foaming agent was added in the amount of 3, 5 7, 10 phr, impact strength was measured as 41.45 KN, 41.20 KN, 40.11 KN, 39.86 KN. In research (III), effect of impact energy on the addition of microcapsule foaming agent EVA copolymer, Addition of 3 phr ADCA foaming agent in EVA Copolymer, compared with adding 3 phr ADCA and 3 phr microcapsules foaming agents . Test discovery at different impact Heights 910 mm, 1115 mm, 1320 mm, 1520 mm, the effect of adding microcapsule foaming agent is better than that without adding microcapsule foaming agent, which is superior to 910 mm : 27.6 %, 1115 mm : 33 %, 1320 mm : 14.7 % and 1520 mm : 4.49 % of shock absorption effect. Therefore, when the impact energy exceeds a certain value, the strength of microcapsule can not disperse the impact force effectively, and the shock absorption effect will become worse.