High-Performance Bio-Based Thermosetting Resins Composed of Dehydrated Castor Oil and Bismaleimide

摘要

The reaction of dehydrated castor oil (DCO) and 1,1'-(methylenedi-4,1-phenylene)bismaleimide (BMI) in 1,3-dimethyl-2-imidazolidinone (DMI) at 130 degrees C for 6 h and Subsequent precipitation gave DCO/BMI prepolymer, which was Cured at 200 degrees C for 2 h gave DCO/BMI cured product. The FE-SEM analysis revealed that the cured products with C=C ratio 2/1 and 1/1 are homogeneous, whereas phase separation occurs for the 1/2 product. The glass transition temperature, 5% weight loss temperature, and tensile modulus of the cured DCO/BMI increased with increasing BMI content. Regarding the tensile strength, the cured DCO/BMI 1/1 product showed the highest value. To evaluate the reaction of DCO and BMI, the model reaction products of DCO and N-phenylmaleimide (PMI) in DMI were analyzed by H-1 NMR spectroscopy. The H-1 NMR data of DCO revealed that DCO has about 4.8 CH=CH bonds per triglyceride and that the ratio of conjugated and nonconjugated diene moieties is about 41/59. The NMR data of the reaction products Of DCO/PMI with the C=C ratio 2/1. and 1/1 at 200 degrees C for 24 h revealed that both Diels-Alder and ene reactions occurs in addition to radical polymerization.