Preparation And Characterization Of Bio-based Rigid Polyurethane Foams

Rigid polyurethane foams(RPUF)are extensively used in numerous fields,such as insulation materials,transport package,for their light weight,good heat insulation,excellent mechanical properties.In this work,biomass polyol was obtained from peanut shell through one step catalytic liquefaction technology.And arious aspects of performance of RPUF were tested.The experimental results are as follows:(1)The peanut shell was used as raw resource for liquefaction reaction.The effects of reaction parameters on liquefied rate were discussed.The optimizing conditions were obtained.In this case,the sulfuric acid content,mass ratio between polyethylene glycerol,plycerol,and peanut shell power,liquefaction temperature,and time were 1.5%(relative to all raw materials),8/2/1,150 ℃,and 2 h,respectively.Furthermore,the hydroxyl number,acid number,viscosity and molecular weight of liquefied products were 451.91 mgKOH·g-1,8.92 mgKOH·g-1,47 mPa·s and 312.5 g·mol-1,respectively.(2)The bio-based RPUF were successfully prepared based on liquefied products.The effect of reaction parameters on the properties of RPUF was discussed.The optimizing conditions were obtained with liquefied products of 100 portions,deionized water of 2.0-2.5 portions,A-33 of 1.0 portion,T-9 of 0.3 portions,L-580 of 2.0-2.5 pottions and PAPI index of 1.0-1.1.The foaming time of the RPUF was prolonged 3 times compared to original RPUF.The density and compressive strength of the RPUF cured in room temperature werer 50-60 kg·m-3 and 190 KPa,respectively.Meanwhile,the open-cell ratio,water absorption and swelling ratio were effectively reduced due to addition of auxiliary blowing agents,such as acetone,petroleum ether and diethyl ether.The application performance of RPUF in thermal insulation field was improved.(3)The RPUF filled with peanut shell were synthesized and their properties were characterized.It indicated that the density was 150-160 kg·m-3.And the compressive strength was up to 814.6 KPa.The average cell size was reduced from 412 μm to 252 μm.The density of RPUF composited with liquefied products and peanut shell was 80-90 kg·m-3.The maximal compressive strength of RPUF was 186.4 KPa.The average cell size of RPUF was reduced from 888 μm to 618 μm.(4)The new additive-type fire retardant was synthesized with cyclohexene,sodium hypophosphite and aluminum sulfate.The optimizing conditions were obtained,where the molar ratio between sodium hypophosphite and cyclohexene,azodiisobutyronitrile(mass ratio for sodium hypophosphite),reaction temperature and time were 1/3,5 %,80 ℃ and 12 h,respectively.The products and aluminium phosphinate(DEPAl)were added to synthesize flame retardant RPUF.The test result of burning behavior of flame retardant RPUF indicated that the grade of combustion property was B1,which was better than the flame-resistant efficiency of DEPAl.