Research On Synthesis Of Nitrogen Heterocyclic Flame Retardant Polyols

Rigid polyurethane foam is widely used as fire-retardant and insulation material in thefields of chemical industry, construction, refrigeration and aerospace because it has thecharacteristics of light weight, low water absorption, weather resistance, low thermalconductivity and other significant good physical and chemical properties. However，thepolyurethane without flame retardant treatment is easy to burn, in addition, the burnedpolyurethane will release a lot of toxic fumes which will endanger the safety of people’s life.It is usually to add flame retardant to improve the flame retardant performance ofpolyurethane. However,the flame retardant have a lot of negative impacts on rigidpolyurethane foam, for instance,the foam structure and the dimensional stability；worsestill,the flame retardants will be gradually released into the environment, and still be harmfulto people’s health, In this paper,we adopt the method of chemical structure modification thatintroduce the flame-retardant unit into the molecular structure of the polyester polyol forimproving the flame retardant of rigid polyurethane foam. Meanwhile, the introduction of therigid structure had improved the compressive of the rigid polyurethane foam and reduced theamount of flame retardants. The main contents and conclusions of this study are as follows:1、Using the wasted polyethylene terephthalate （PET）as raw material, anhydride aschain extender, and then add amount of catalyst to the polyester polyol, we studied the effectsof the substance dosages on the acid number, hydroxyl value and viscosity of the polyesterpolyol, The results show that: the affecting order for acid number is:catalyst> hydramine>PET> anhydride, the order for hydroxyl value order is: catalyst> PA> PET> ethanolamine.Meanwhile, we also characterized the structure of the polyester polyol, the spectra shows thatthe polols we prepared contain terminal hydroxyl group-OH or-NHCO-(or both), C=O,C-O-C.2、 Tris (hydroxymethyl)-1,3,5-triazinel (THMIC) was synthesized using1,3,5-triazine-2,4,6-triol and formaldehyde as raw material.The effect of temperature, time,pH and other factors on the reaction were investigated. FTIR characterizations showthat THMIC groups are introduced into the molecular structure with a viscous and clearliquid. 3、Through the reaction of THMIC with polyester polyol, flame structure THMIC，thepolyester polyol was successfully prepared. The influence of the material contents on acidnumber follows the sequence catalyst> anhydride> polyol. The influence of the materialcontents on number follows the sequence: polyol> anhydride> catalyst. The polyurethanefoam prepared has a oxygen index of28with a density of38kg/m3,which meet with thenational level B2requirements.