Biobased thermosetting resins composed of L‐lysine methyl ester and bismaleimide

Abstract

Lysine methyl ester (LME), which was generated in situ by the reaction of lysine methyl ester dihydrochloride and triethylamine in dimethyl sulfoxide (DMSO), was prepolymerized with 4,4′‐bismaleimidodiphenylmethane (BMI) at 80°C for 2 h in DMSO. Then, the formed prepolymer was precipitated in water. The obtained LME/BMI prepolymers with molar ratios of 2:2, 2:3, and 2:4 were compression‐molded at a final temperature of 230°C for 2 h to produce cured lysine methyl ester/4,4′‐bismaleimidodiphenylmethane resins (cLBs; cLB22, cLB23, and cLB24, respectively). Fourier transform infrared (FTIR) analyses revealed that the Michael addition reaction of amino groups to the CC bonds of the maleimide group occurred in addition to the homopolymerization of the maleimide group. The glass‐transition temperature (Tg) and 5% weight loss temperature (T5) of the cured resin increased with increasing BMI feed content, and cLB24 showed the highest Tg (343°C) and T5 (389°C). The flexural strengths (131–150 MPa) and moduli (3.0–3.6 GPa) of the cLBs were comparable to those of the conventionally cured resins of BMI and 4,4′‐diaminodiphenylmethane. Field emission scanning electron microscopy analysis revealed that there was no phase separation for all of the cured resins. Although cLB23 and cLB24 were not biodegradable, cLB22 had a biodegradability of 8.5% after 30 days in an aerobic aqueous medium containing activated sludge. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40379.

Amino acid-incorporated polymer network by thiol-ene polymerization

“…Li et al [34] reported a polymer network by the reaction of a cycloaliphatic epoxy resin with DL-lysine, or diglycidyl ether of bisphenol A with L-tryptophan [35]. We also reported a polymer network by the reaction of 4,4"-bismaleimidodiphenylmethane with L-lysine [36]. Recently, radical-mediated thiol-ene 'click' reactions have attracted increasing attention as a method for the production of crosslinked polymer networks with various frameworks and functional groups [37][38][39][40].…”

Thermosetting bismaleimide resins generating covalent and multiple hydrogen bonds

“…ML and DAIC can undergo MHB as is shown in Figure , in a similar manner to melamine cyanurate analogs . Amino groups of ML are possible to undergo Michael addition with maleimide groups of BMI in a similar manner to the curing reaction of BMI and DDM . Leu reported that addition copolymerization of triallyl isocyanurate and BMI occurs when triphenylphosphine (TPP) was used as a catalyst .…”

“…[24][25][26][27] Amino groups of ML are possible to undergo Michael addition with maleimide groups of BMI in a similar manner to the curing reaction of BMI and DDM. 28,29 Leu reported that addition copolymerization of triallyl isocyanurate and BMI occurs when triphenylphosphine V C 2015 Wiley Periodicals, Inc.…”

“…29,33 In the FT-IR spectrum of BMI-DAIC11, the bands characteristic to maleimide group around at 1148, 837, and 689 cm 21 and those characteristic to allyl group around at 989 and 939 cm 21 were almost nonexistent, and the band characteristic of succinimide moiety was observed at around 1186 cm…”

Soluble asymmetric bismaleimide with low molten viscosity and its high glass transition temperature polymer

“…To overcome these disadvantages and extend the application of BMI, great efforts have been made to improve the processability of BMI while maintaining its excellent thermal performance. One strategy is the copolymerization of BMI with expanding agents or other high performance resins such as diamine, allylic compound, cyanate ester, epoxy resins, and benzoxazine . Another effective strategy is the modification of BMI's chemical structure.…”