ABSTRACT
Keywords .......................................................................................................... 418 Acknowledgment .............................................................................................. 418 References ......................................................................................................... 418
14.1 FIRE-RESIST BIO-BASED POLYURETHANE FOR STRUCTURAL FOAM APPLICATION
14.1.1 POLYURETHANE (PU) AND ITS PROPERTIES
PU is a versatile thermosetting polymer. Its properties are modified either by varying the microstructure or by dispersing either inorganic or organic fillers within the PU continuous matrix (Oertel 1993). PU is a high molecular weight polymer based on the polyaddition of polyfunctional hydroxyl group and isocyanate. There are two types of polyhydroxyl compounds commonly used namely polyester and polyether polyols. Polyester is a high molecular weight substance which contain ester group as the repeating unit in the chain. The mechanical properties and morphological structure of PU depend mainly on the polyol structure, molar mass and its functionality and to a lesser extent, on the nature of the polyisocyanate (Badri et al. 2000). PU foam is formed by gas evolution (either carbon dioxide or chlorofluorocarbon) trapped during the polymerization process between the hydroxyl-containing group compound with polyisocyanate to form urethane chain. The resulted foams would exhibit the relationship between physical and mechanical properties with their chemical composition and density of materials (Oertel 1993).
