Investigation of the Potentials of Oil Palm Frond Fibre for Thermal Insulation of Food Flasks

Abstract

Natural fibers obtained from oil palm fronds at Offa, Nigeria were investigated for reinforcement of heat-resistant lining for hot food flasks. Frond fibre was subjected to 5% NaOH chemical treatment to impose better surface property and used to reinforce polypropylene matrix as composites with 10%, 20%, 30% and 40% fibre loading. Treated frond fibre, polypylene matrix and samples of fabricated composites were subjected to standard chemical, mechanical and physical tests including density/hardness, impact/tensile strengths and thermogravimetric/thermal conductivity analyses following standard procedures. The test  equipment included injection molding machine, Instron tensile tester, Tinius impact tester, Rockwell hardness tester, Perkin Elmer instrument and Lees disc apparatus; accessed in workshops/laboratories of Kaduna Polytechnic, Ahmadu Bello University, Zaria, Engineering Materials Development Institute, Akure and Federal University of Technology, Minna. The characterization result showed the composite was nontoxic to humans if it contacted food in the flask. The physical, mechanical and thermal properties showed that only 20%-40% fibre loading was beneficial after which performance declined. Mechanical properties of frond reinforced composites (density, hardness, impact and tensile strength) were adequate for required service condition. The decomposition temperature of the composites was about 4800C which was above 3500C-4350C for most conventional domestic insulators, 2900C for pure treated frond fibre and 4350C for polypropylene matrix. Thermal conductivity reduced from 0.0035Wm-1K-1 to 0.0025Wm-1K-1 for 20%-40% 10mm thick fibre loaded composites. For 50mm thick conventional domestic insulators, it was 0.11- 0.23Wm-1K-1 for polypropylene matrix, 0.066Wm-1K-1 for rock wool, 0.036Wm-1K-1 for glass fibre and 0.03Wm-1K-1 for polystyrene, confirming the superiority of the frond reinforced composites as minimized thermal conductivity is the most critical determinant of material suitable for thermal insulation.