High‐performance bio‐based thermosetting resins composed of dehydrated castor oil and bismaleimide

Abstract

AbstractThe reaction of dehydrated castor oil (DCO) and 1,1′‐(methylenedi‐4,1‐phenylene)bismaleimide (BMI) in 1,3‐dimethyl‐2‐imidazolidinone (DMI) at 130°C for 6 h and subsequent precipitation gave DCO/BMI prepolymer, which was cured at 200°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 1H NMR spectroscopy. The 1H 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°C for 24 h revealed that both Diels–Alder and ene reactions occurs in addition to radical polymerization. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009