The microstructure

responding degree and main properties of unsaturated polyester modified with polyurethane were studied with SEM

FT-IR

contact angle and mechanical properties testing.The study showed that with the addition of polyurethane

the toughness of unsaturated polyester was improved

the interface soaking with natural fiber was increased and the curing shrinkage rate was lowered.The impact fracture section of modified unsaturated polyester showed ductile failure.The interface soaking with natural fiber was increased when the contact angle was lowered with the increase of polyurethane content.The testing of mechanical properties showed that when the content of PU was 5%

the impact strength was increased by 80%

the decrease of flexural modulus was less than 20% and the curing shrinkage rate was less than 4%.