A Study of Fire Retardant Effect in Natural Fiber Composite Panels with Magnesium Hydroxide and Zinc Borate as Additives TENGKU NURAITI TENGKU IZHAR 1, a , CHAN CHOON JIAT 2,b and Nabilah Aminah Lutpi 3,c 1,2,3 School of Environmental Engineering, Universiti Malaysia Perlis (UniMAP), Kompleks Pusat Pengajian Jejawi 3, 02600 Arau, Perlis, Malaysia a nuraiti@unimap.edu.my, b billy-ccj@hotmail.com, c nabilah@unimap.edu.my Keywords: Natural fibers, fire retardant Abstract. The objective of this study is to investigate the fire retardancy effect of coconut coir, rice husk and sawdust panels which are incorporated with magnesium hydroxide (Mg(OH) 2 ) and zinc borate (2ZnO·3B 2 O 3 ·3.5H 2 O) as additives. The natural fiber and additives are mixed and cured for one week, with polyester resin and hardening catalyst as binders. Fire retardancy of these panels are tested according to American Society for Testing and Materials (ASTM) Horizontal (D 365) and Vertical Burning (D 3801) tests. Principle of fire retardants and mechanism of polymer combustion are shown in this study too. The study revealed that the sawdust panels with both additives have the highest fire retardancy compared to rice husk and coconut coir panel with both additives. Introduction Over the years, the demand for natural fiber composites such as coconut coir fiber and rice husks for manufacturing industries had been increasing due to the economical and environmental advantages over the conventional composites [1]. These advantages includes their attributes that light in weight, cheap, has good specific strength, biodegradable, and produces low to none poisonous substance [2]. Usually, natural fiber composites are easily ignitable, and the improvement of the composite’s resistance to fire is very important, as it can increase people’s safety and to protect their properties. Hence, addition of fire retardants into these natural fiber composites can prevent the spreading of fire and natural fiber can widely used as a main ingredient in the manufacturing industries. Polymer combustion mechanism. The chemical structure of polymers is mainly made of carbon and hydrogen and proves to be highly combustible [3]. Combustion is made of two factors, which are oxidizing and reducing agents. The burning process starts with an increasing temperature of the polymer caused by a heat source until a bond scission occurs. Polymer fragments, which are volatile, will diffuse into air and creates a burnable gaseous mixture, also known as fuel. The fuel ignites when the activation energy of the burning reaction is attained, releasing heat. Besides, it can also start burning at lower temperatures, known as a flash point, when it is being excited with external energies like sparks or flames [4]. The duration of combustion depends on the amount of heat released during the burning of the fuel. If the heat is increased to a whole new level, that means more burning occurred. Principle of fire retardants. Some flame retardants undergo endothermic decomposition by inducing a temperature decrease by heat utilization. The reaction medium needs to be cooled to below the polymer burning temperature to prevent fire spread. Furthermore, some flame retardants produces a barrier or gaseous layer where burning takes place and thermal degradation occurs. The barrier reduces the movement between volatile fuel and oxygen, and causes less reaction, thus reduces burning [4]. Applied Mechanics and Materials Vol. 815 (2015) pp 148-152 Submitted: 2015-08-27 © (2015) Trans Tech Publications, Switzerland Accepted: 2015-09-01 doi:10.4028/www.scientific.net/AMM.815.148 Online: 2015-11-30 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, www.ttp.net. (ID: 121.123.137.73-03/12/15,13:57:36)