Effects of compound formulations and processing conditions on the
properties of extruded EPDM and NR/EPDM Blend Foams
อิทธิพลของสูตรยางคอมปาวด์ และกระบวนการผลิตต่อสมบัติของท่อโฟมยางอีพีดีเอ็ม
และท่อโฟมยางเบลนด์ยางธรรมชาติและยางอีพีดีเอ็ม
Chonlada K. Lewis, D. of Rubber Tech. and Polymer Sci., F. of Sci. and Tech., PSU.
Yudtana Rodlum, M.Sc. Student in Polymer Tech., PSU.
Sarote Changchum, M.Sc. Student in Polymer Tech., PSU.
Corresponding e-mail : kchonlad@bunga.pn.psu.ac.th
Grant : Government Budget
Presented : The Polymer Processing Society (PPS) Asia/Australia Regional Meeting 1999,
December 1-3, 1999, Bangkok, Thailand
Key words : EPDM Foam, NR/EPDM Foam, chemical blowing agents
The effects of compound formulations and processing conditions on the structure and proper-ties of extruded EPDM and EPDM/NR tube foams have been investigated. The tube foams were prepared by mixing a compound in a two roll mill, extruding the compound through a cold feed ex-truder and finally vulcanizing the extrudate in a circulating hot air oven. In previous results, the EPDM grade, blowing agent type, composition of EPDM blend and processing conditions were found to affect the cell structure and the physical properties of the resultant EPDM foams. An extended
work was carried out using blowing agent blends and NR blending with EPDM as a based rubber.
The characterisitcs of blowing agent blends (ADC/DNPT and ADC/OBSH ) were studied using a
gas evolution apparatus. Decomposition temperature of ADC decreased with both DNPT and OBSH blending which affected the resultant EPDM foams structure and properties.
To promote the use of natural rubber, its various compositions were blended with EPDM to produce the tube foams. Modified formulations were needed to ease the difficulty of mixing and sta-bilising the resultant foams. Using a tube mold for an extrudate as an alternative technique to vulca-nize the NR/EPDM extrudate in the hot air oven was successfully found to control the expansion and foam dimensions. The NR compositions were also found to affect the foam structure and properties.
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