VOL. 11, NO. 20, OCTOBER 2016 ISSN 1819-6608 ARPN Journal of Engineering and Applied Sciences © 2006-2016 Asian Research Publishing Network (ARPN). All rights reserved. www.arpnjournals.com 12053 SYNERGISTIC EFFECTS OF ZINC BORATE AND HALLOYSITE NANOTUBES (HNTS) ON CHAR MORPHOLOGY AND GASES EMISSION OF EPOXY BASED INTUMESCENT FIRE RETARDANT SYSTEMS Qandeel Fatima Gillani 1 , Faiz Ahmad 1 , Muhammad Ibrahim Abdul Mutlib 2 , Puteri Sri Melor 1 and Adiat Arogundade 1 1 Department of Mechanical Engineering, Universiti Teknologi Petronas, Bandar Seri Iskandar Perak, Malaysia 2 Department of Chemical Engineering, Universiti Teknologi Petronas, Bandar Seri Iskandar Perak, Malaysia E-Mail: qandeelgillani@gmail.com ABSTRACT In this study, Zinc Borate (ZB) and Halloysite nanotubes (HNTs) are simultaneously integrated in the in expandable graphite (EG) based intumescent fire retardant coatings. The synergistic effect between the ZB and HNTs on fire performance, char morphology, and thermal degradation of IFRC were investigated. The IFRC of ZB/HNTs (5.5:1.5) showed noticeable improvement in char quality. Similar ratio of incorporated additives showed significant reductions in the phenolic gasses emission of IFRC. FESEM results showed that a solid and dense char layer was formed in ZBH (5), which hindered the transfer of heat to substrate and hold combustible gases in the condensed phase reaction. It is concluded that the combination of ZB and HNTs is proved to be a supportive synergism in development of environment friendly intumescence coating systems. Keywords: zinc borate, halloysite nanotubes, char morphology, fire performance, thermal stability, intumescent fire retardant coatings. INTRODUCTION Intumescent Fire retardant coatings are easiest and oldest way to protect steel structures from reparations of fire accidents. An intumescent formulation require to be optimized in terms of physical (char strength, expansion, viscosity, morphology, heat conductivity etc.) and chemical (thermal stability, reactivity) properties in order to form an efficient protective char which will be able to protect steel substrate [1] . Pervious works have already been completed on the chemical characterization of Intumescent fire retardant coatings for the assessment of their thermal stability [2], [3],and [4] but only few papers deal with the investigation of the gaseous emissions during intumescence degradation[5]and[6]. Polymer epoxy resins are an essential part of Intumescent coatings formulations. They perform well as a binder in intumescent fire retardant systems but with one limitation. On thermal degradation they release toxic gases, like phenols, aniline, toluene, ammonia etc. to the environment which are health risk for people entrap in fire locations. One of the main challenges is to find out the optimum ratio between all additives of Intumescent formulations to reduce the gaseous emission while keeping the fire performance high. Reduction in toxic gaseous emission can be attained by choosing the suitable additives that can chemically convert aromatic hydrocarbons into aliphatic compounds [7] . Some fillers such as wollastonite, kaolin clay, and alumina can involve in endothermic reactions at high temperatures, are previously used to enhance the fire performance. It has been proven that zinc borate perform well as a flame retardant additive and suppress smoke when used with in different polymers like PVC [8], polyamide [9], polyolefin [10], epoxy, phenolic, and various elastomers [11]. Similarly, the use of different clays in intumescent fire retardant coating formulations is well known technique, to decrease their flammability. Clays are usually compounded in high fractions with the polymer to create best hindering effect through sturdiest char [12, 13] Since 1990s, several nano clays, montmorillonite clay OMMT, and two fibrous clay minerals; palygorskite (PAL), halloysite (HAL), and sepiolite (SEP) was have been reported as synergists in IFRs. Previous studies reported that improvement in the fire retardant properties of IFRC can be achieved by the addition of hallyosite nanotubes in intumescent coating formulation[14]. The zinc borate contribution has also been recognized in development of glassy char layer at the surface of the polymer during condensed phase of combustion reaction, and protects steel substrate [15]. This effectively reduces the infusion of volatile compounds through the external char, and limits them from entering the gas phase., Zinc borate is also known as natural smoke suppressant agent and it has been acknowledged for its capabilities to suppress smoke that often arise during the burning of a polymers. In addition ,It has a natural tendency to break aromcity of phenolic comounds used in Intumescent fire retardant formulations, through crosslinking[15]. On the other hand, halloysite nanotubes (Al2Si2O5 (OH) 4) contain 39.8% alumina and 46.3% silica. These both element can emerge heat shielding effect dynamically[16]. Current Study reveals the synergist effects of halloysite nanotubes and zinc borate on the char morphology and gaseous emissions of Intumescent fire retardant coatings.