Preparation And Properties Of Phosphorus Block Containing Soybean Oil Based Rigid Polyurethane Foam

Rigid polyurethane foam is common organic polymer materials with low density,excellent thermal insulation and mechanical properties,which is widely applied in construction,decoration,refrigerators and other fields.However,rigid polyurethane foam burns easily and can produces large amount of toxic smoke,which greatly limit their application in different fields.At the same time,with the depletion of petroleum resources and the worsening of environmental problems,the development and utilization of renewable resources to replace or partially substitute petroleum-based raw materials for the preparation of rigid polyurethane foam has drawn wide attention.Soybean oil is a renewable resource with high yield and low price that contains ester and double bond in structure.Soybean oil based polyol can be obtained by chemical reaction,which can be used as polyol raw materials for polyuretane rigid foams.Therefore,using soybean oil instead of petroleum resources to prepare rigid polyurethane foam with good flame retardant properties plays an important role in the utilization of renewable resources,environmental protection and the development of rigid polyurethane foam field.In this paper,soybean oil based polyol was prepared by soybean oil,then phosphorus block containing soybean oil based rigid polyurethane foams were prepared with soybean oil baesd poyol,isocyanate and other raw materials.The corresponding properties of the foams were studied.The main research contents are as follows:1.Phosphorus-containing polyol(THPO-PO)was obtained by reaction between tris(hydroxymethyl)phosphineoxide(THPO)and propylene oxide(PO).The polarity of THPO is reduced,and the compatibility with the polyol is improved after the reaction.The effects of reaction temperature,reaction time,catalyst content and substrate mass ratio on the reaction process were also discussed.The structure of THPO-PO was characterized by fourier transform infrared(FT-IR)and nuclear magnetic resonance(1H NMR).2.Soybean oil based polyol(LSBP)was obtained by the reaction of epoxy soybean oil and lactic acid.The structure of LSBP was characterized by FT-IR and1H NMR.The compatibility of different mass ratios of THPO-PO with LSBP was tested.Flame-retardent soybean oil based rigid polyurethane foams were prepared using varying mass ratios of THPO-PO and LSBP.Finally,the performance of the foam was tested by thermogravimetric analysis,compression experiments,scanning electron microscopy,limit oxygen index(LOI)and vertical burning test.The results show that with increasing THPO-PO content in the mixed polyols,all foam cell structures are spherical or polyhedral,the apparent density of the foam decreases,and the compressive strength first increases and then decreases,the initial degradation temperature of the foam decreases and the flame retardant performance has been significantly improved.The limit oxygen index(LOI)of foam reaches 27.5 and the vertical burning reaches V-0 level as the THPO-PO content increases to 40%in mixed polyols.3.Phosphorus-free soybean oil based polyol(HSBP)and phosphorus-contianing soybean oilbased polyol(DSBP)were prepared by the reaction of epoxy soybean oil with water and DOPO,respectively.The structure of LSBP and DSBP were characterized by FT-IR and 1H NMR.Flame-retardent soybean oil based-rigid polyurethane foams were prepared by using different mass ratios of DSBP and HSBP.The thermogravimetric analysis,compression test,scanning electron microscopy,limit oxygen index(LOI)and vertical burning test were used to study the performance of foams.The results show that with the increase of the content of DSBP in the mixed polyol,the foam cell structure is round or oval,the apparent density and compressive strength decreases,and the flame retardant property is obviously improved.The limit oxygen index of foam reaches 28.3 and the vertical burning reaches V-0 level as the DSBP content increases to 80%in mixed polyols.