Bismaleimides chain‐extended by imidized benzophenone tetracarboxylic dianhydride and their polymerization to high temperature matrix resins

Abstract

SynopsisHeat-resistant polymers were obtained by thermal polymerization of several bismaleimides or their substituted derivatives. The chain of the polymer precursors was extended by incorporation of imidized benzophenone tetracarboxylic dianhydride between the maleimide rings in order to impart a degree of flexibility in the polymers. The bismaleimides and their corresponding tetraamic acids were characterized by infrared (IR) and proton nuclear magnetic resonance ('H-NMR) spectroscopy. The differential thermal analysis (DTA) thermograms of the monomers showed exotherms at 200-340°C attributed to the thermally induced polymerization reactions. The influence of different substituents in the maleic double bond on the curing temperature was investigated. The thermal stability of the cured resins was evaluated by thermogravimetric analysis (=A) and isothermal gravimetric analysis (IGA). They were stable up to 367-433°C both in nitrogen and air atmosphere and afforded 57768% char yield at 800°C under anaerobic conditions. The structure of the aromatic and aliphatic diamines utilized for imidization was correlated with the thermal stability of the cured resins. The bismaleimide derived from p-phenylenediamine gave the most heat-resistant resin because of its higher rigidity.

Syntheses and Characterizations of Bis(trialkoxysilyl)oligoimides, 1 Synthesis of Model Compounds and Study of the Thermal Self-Crosslinking

“…The crosslinking process is studied starting from three precursors: the a-x-(trimethoxysilyl) nadimides 2 b, pyromellitic diimide 3 b and the a-x-(triethoxysilyl) pyromellitic diimide 3 a. FT-IR analyses, after thermal treatment of bis(a,x-trialkoxysilyl)imide precursors, are summarized in Table 2. During the crosslinking process, the intensities of the C1H absorption band at 2 840 cm -1 for C1H of Si(OCH 3 ) 3 and at 2 975 cm -1 for C1H of Si(OCH 2 CH 3 ) 3 were monitored. Figure 2 shows the decrease of the C1H absorption band of the resulting crosslinked material prepared with precursors bis(a,x-trimethosilyl)imides 2 b (Figure 2a) and 3 b (Figure 2b).…”

“…A great variety of different thermosetting polyimides has been studied, which combine good processability and high thermal stability. Bismaleimides, [3] bis(maleimide)/ bis(allylyphenol A) systems, [4] bisnadimide, such as the well-known PMR15 resin, [5] bisbenzocyclobutene, [6] and acetylene-terminated [7] oligoimides are the main types of thermosetting resins. However, all these functional groups undergo addition reactions at elevated temperature.…”

Gamma‐ray irradiation effect of polyethylene on dimaleimides as a class of new multifunctional monomers

“…The bismaleimides were synthesized according to the method used in previous studies 8–12. In general, a diamine is condensed with maleic anhydride to give the corresponding bismaleamic acid, which upon elimination of water yielded the bismaleimide.…”

Thermal Properties Improvement of Bismaleimide Resin by a New Phosphorus‐containing Polycyclic Bismaleimide

“…exothermic temperature increased in the order of BDM < BDE < BMPI < BDS. Mellissaris and Mikroyannidis 28 have reported the exotherm shifted to a higher temperature as the length and the formula weight of the bridge between maleimide groups was increased. In the case of BMPI has a greater formula weight between two maleimide groups than that of BDE or BDM, it is reasonable to explain BMPI that has a higher curing exotherm than BDE or BDM do.…”