Preparation and characterization of combustion modified polyurethane

Baysal, Pelin
Polyurethane (PU) flexible foam is a cushioning material which is very versatile and high quality. Among them, high resilience (HR) foam provides better support factor which means it is highly comfortable. Polyurethane foam is combustible due to its chemical nature. Ignition of upholstered furniture caused increasing in residential fires and also people died. In this work modified high resilience polyurethanes with Polyisocyanate Polyaddition (PIPA) Polyol will be prepared to improve combustion characteristics and thermal stability. Besides, British Standard 5852 which the United Kingdom bedding and furniture legislation is based was used to classify combustion properties of modified HR foam. Important variables are the filler and the liquid flame retardant (halogenated phosphorus type). PIPA Polyol which is one of the combustion modified polyether polyol is used for polyurethane production as an additive. The most important characteristic of this polyol usage is its contribution to combustibility of polyurethane foam. For this aim, 20% solid content PIPA and Tris(2-chloroisopropyl) Phosphate (TCPP) are used as an additive in PU foam. After conducting several trials, formulation of polyurethane includes PIPA Polyol was rearranged and obtained working polyurethane. The foam samples were analyzed structurally by density, hardness, resilience and compression set tests. By the additives, these properties showed slight changes. Density, support factor (SAG) and resilience properties were developed. Furthermore, mechanical properties of foams which are tensile strength and elongation at breaks were also studied. After making combustion modified foam, tensile strength and elongation at break decreased. Decrease of both tensile strength and elongation at break is associated with the shortening of soft segment length. Thermogravimetric Analysis (TGA) and Direct Pyrolysis Mass Spectrometry (DP-MS) has been used to support thermal characterization. Addition of PIPA and flame retardant increased the thermal stability of foam. Modification of flexible HR PU foam showed the effective way of the flammability and the thermal stability. BS 5852 test result indicated that overall combustion behavior depends on filled polyol.