Synthesis Of Rapeseed Straw Based Polyols And Its Research In The Polyurethane Rigid Foam

In this paper,a novel synthetic process was developed to synthesise the rapeseed straw based polyols and prepare a low cost and green polyurethane rigid foam.Firstly,this paper studied the polyhydroxy alcohol liquefaction of rapeseed straw which was pretreated by the different microwave conditions.The factors among microwave pretreatment power and time,the liquid-solid ratio,sulfuric acid dosage and the reaction temperature and time on the liquefied effects of liquefaction of rapeseed straw were systematically investigated.The results showed that the best liquid-solid ratio of 6:1,2%sulfuric acid dosage,temperature of 160?,reaction time of 40 min,the residue rate was only 3.9%,the hydroxyl value and viscosity of liquefaction product were 292.8 mg KOH/g and 3510 mPa·s/25?,respectively.Secondly,SO42-/ZrO2 solid superacid was prepared by precipitation impregnation method and used as catalyst to study the hydrothermal synthesis of rapeseed straw between 180? to 240 ?.The factors among liquefaction temperature,reaction time and the amount of solid superacid on the liquefied effects of liquefaction of rapeseed straw were systematically investigated.The results showed that the best reaction temperature among 200?240 ?,the reaction time of 2 h,and 4%solid super acid dosage,the rapeseed straw conversion rate could reach 84%,the hydroxyl value and viscosity of liquefaction product were 258.6 mg KOH/g and 3160 mPa·s/25?,respectively.Finally,this paper used the rapeseed straw based polyols as matrix resin which was supported by foaming catalyst,foaming agent,foam stabilizer and so on,and isocyanate to prepare polyurethane rigid foam material.The factors among the dosage of foaming agent,foam stabilizer and isocyanate on the properties of the polyurethane rigid foam were systematically investigated.The results showed that the best molar dosage of foaming agent,foam stabilizer and isocyanate are 6%,5%and 1.5 of the white materials,the rapeseed straw based polyurethane rigid foam has a compressive strength of 0.192 Mpa and a oxygen index of 26,with excellent cell structure and dimensional stability.