Biobased thermosetting resins composed of terpene and bismaleimide

Prepolymers prepared by reactions of 1,1-(methylenedi-4,1-phenylene)bismaleimide (BMI) with myrcene (Myr) and limonene (Lim) in 1,3-dimethyl-2-imidazolidinone (DMI) at 150 degrees C were compressed at 250 degrees C to produce crosslinked Myr/BMI [molar ratio = 2:22:5 (MB22MB25)] and Lim/BMI [molar ratio = 1:1 (LB11)] resins. The 1H-NMR analysis of the model reaction products of Lim and Myr with N-phenyl maleimide (PMI) in DMI at 150 degrees C revealed that a DielsAlder reaction for Myr/PMI and a vinyl copolymerization for Lim/PMI preferentially proceeded in addition to the occurrence of the ene reaction to some extent. The Fourier transform infrared data of the cured resins were consistent with the results of the model reactions. All of the cured resins, except for MB22, showed tan peak values and 10% weight loss temperatures that were higher than 330 and 440 degrees C, respectively. The flexural strength and modulus values of the MBs were higher than those of LB11. Field emission scanning electron microscopy analysis revealed that MB22MB24 were homogeneous, whereas some combined particles appeared in LB11. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013