Preparation Of Polyurethane Elastomer Based On Castor Oil

Polyurethane elastomer(PUE)is a type of elastomer which has many urethane group in backbones.Its overall performance is between rubbers and plastics.It is widely used in various fie1 ds of national economy because of its outstanding resistance to oil,resistance to abrasion,resistance to low temperature and remaining high elastic characteristics in a wide range of hardness,etc.PUE is generally synthetized by polyols,isocyanates and chain extenders by the step-growth polymerization.Oligomer polyols usually contains polyether polyols,polyester polyols,polycarbonate polyols,etc.Whatever polyether polyols or polyester polyols their raw materials all come from oil resources.In this study castor oil is used to synthesize PUE instead of oil based oligomer polyols which is widely use currently.All PUEs were characterized by DSC,TGA and mechanical testing.Test results indicate that prepolymer based on castor oil has lower viscosity than prepolymer based on polyether polyol and polycaprolactone polyol.PUE based on castor oil has better heat resistance,hydrolysis resistance,UV resistance than PUE based on polyether.PUE based on castor oil has 85.5% tensile strength retention after 28 days heat aging at 90°C,76.1% tensile strength retention after 28 days hydrolysis aging at 70°C,54.2% tensile strength retention after 1500 h QUV aging cycle.Chain extension coefficient has great impact on properties of PUE.The tensile strength is lower when the chain extension coefficient is higher.The best chain extension coefficient is 0.95.Chain extender has some impact on mechanical properties of PUE.PUE which use BDO as chain extender has better elongation at break than PUE which use WANALINK 6200 and ETHACURE 300 as chain exender.Castor oil could potentially replace oil based oligomer polyols to make high performance PUE in future.