Original scientific paper
Effects of Foaming Agents and Calcium Carbonate on Thermo-Mechanical Properties of Natural Rubber Foams
Nuchnapa TANGBORIBOON
; The Materials Engineering Department, Faculty of Engineering, Kasetsart University, Bangkok, Thailand
Sunisa RORTCHANAKARN
; The Materials Engineering Department, Faculty of Engineering, Kasetsart University, Bangkok, Thailand
Karat PETCHAROEN
Anuvat SIRIVAT
; The Petroleum and Petrochemical College, Chulalongkorn University, Bangkok, Thailand
Abstract
Natural rubber foams were prepared from the vulcanization of natural rubber in a sulfur curing system at 396 K by a two roll mill with foaming agents; sodium bicarbonate (NaHCO3) or N, N´-dinitrosopentamethylene tetramine (DNPT, C5H10N6O2), and with 0, 20, 40, and 60 phr calcium carbonate (CaCO3) as a fi ller. The obtained natural rubber foams are lightweight, with good thermal and mechanical properties, suitable for thermal insulation, energy absorption, and structural uses. Both foaming agents added in the natural rubber, namely NaHCO3 and DNPT, decomposed and released gases at the vulcanization temperature of 396 K to produce open and closed cell structures. Adding of 60 phr CaCO3 fi ller particles into the natural rubber foams enhanced the mechanical and thermal properties as the ionic charges Ca2+ and CO3+ 2- produced the interatomic bondings within the natural rubber foam matrix. The obtained natural rubber foam with the 60 phr CaCO3 fi ller and with NaHCO3 possessed the bulk density, compression set, and thermal conductivity of 240.5 kg/m3, 32.60%, and 0.066 W/mK, respectively. The obtained natural rubber foam with the 60 phr CaCO3 fi ller and with DNPT possessed the bulk density, compression set, and thermal conductivity of 219.0 kg/m3, 11.30%, and 0.070 W/mK, respectively, temperatures above 800°C.
Keywords
calcium carbonate filler; compression set; foaming agents; natural rubber foams; thermal conductivity
Hrčak ID:
137290
URI
Publication date:
28.3.2015.
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