Bismaleimide from maleic anhydride

Difunctional vinvl ether/difunctional N-maleimide. Up until this point, our results have centered on the reactivity of monofunctional maleimide divinyl ether mixtures. From Kloosterboer s26 work for acrylate polymerization, it is known that the rate of polymerization of a free-radical process is increased dramatically as the functionality of the acrylate is increased. In order to enhance the polymerization rates of maleimide divinyl ether systems, it was decided to synthesize difimctional maleimides for copolymerization with difunctional vinyl ethers. The results in Table V indicate that the photoinitiated TTDBM [bismaleimide made from maleic anhydride and 4,7,10-... 

In view of the surprising results obtained for the monofunctional maleimide HM/IPDBDVE system in Figure 3 for polymerization in air, an equimolar mixture of CHVE and MPBM [bismaleimide made from maleic anhydride and 2-methyl-l,5-pentanediamine] was polymerized via a mercury lamp source in the absence and presence of air (Figure 7). As might be expected from the earlier results in Figure 3, the difunctional maleimide/divinyl ether system exhibits a remarkably high polymerization rate in the presence of oxygen (air). 

Oligomers end-capped with maleimide rings, which are known as bismaleimide (BMI) resins, exhibit thermal stability intermediate between epoxies and poly-imides. BMI systems are mainly used to fabricate structural composites capable of sustaining temperatures up to 230°C. Specific versions, such as American Cyanamid FM 32 and Ciba-Geigy Kerimid 601 have been developed to prepare adhesive compositions. Fig. 17 displays a typical constitutive unit of various commercial BMI resins based on bismaleimide 38, prepared from maleic anhydride 37 and 4,4 -methylenebisbenzeneamine (MDA) 34. 

Bismaleimides are obtained from maleic anhydride (section 11.2.2 (b)) and a diamine such as 4,4 -diaminodiphenylmethane ... 

Stable triazolines are obtained from aryl azides and V-alkyl and N-aryl maleimides (Scheme 81 )307-309a the reaction succeeds with silyl azides310 and is utilized in the synthesis of polymers from bisazides and bismaleimides.311 312 Unlike maleimides, maleic anhydrides do not yield stable triazolines with trimethylsilyl azide the reaction products are oxazinediones (Section IV,A).310,313,314... 

A current version of the low molecular weight concept is the use of bismaleimides made from aromatic diamines and/or mixtures thereof and maleic anhydride in admixture with other vinyl monomers. Several commercial formulations of this type are now available as the neat resins or as FRP prepregs. There is considerable current research in this area because of the favorable processibility. However, to date, FRP products of this type are outperformed by the PMR-type polyimides by about 50 C at elevated temperatures. 

SYNTHESIS Bismaleimides are generally prepared from the two-step reaction of maleic anhydride and diamines in the presence of acetic anhydride and catal5dic amounts of nickel acetate and triethylamine. - Sodium acetate may be substituted for nickel acetate. Poly(bismaleimides) are highly cross-linked polymers formed from thermally cured bismaleimides. Thermal curing can be promoted by either a radical-type initiator (peroxides or azo compounds) or an ionic-type initiator such as l,4-diazabicyclo-[2.2.2.]octane (DABCO), 2-methylimidazole and triphenylphosphine. ... 

Commercial bismaleimide thermoset resins are based on aromatic bismaleimides such as 4,4 -bismaleimidodiphenylmethane (Compimid MDAB, Evraiik). Compimid MDAB, also known in literature as MDA-BMT is derived from the condensation reaction between 4,4 -methylene dianiline (MDA) and maleic anhydride, both relatively low-cost monomers. The MDA-BMI is often used as a eutectic mixture with other BMIs such as TDA-BMI, to reduce its melting point for improved impregnation and tackiness in the glass and carbon-fiber-based composite prepregs. 

Bismaleimides (BMI). The hismaleimide resins have found their niche in the high-temperature aircraft design applications where temperature requirements are in the 177°C (350°F) range. BMI is the primary product and is based upon the reaction product from methylene dianiline (MDA) and maleic anhydride bis (4 maleimidophynyl) methane (MDA BMI). Variations of this polymer with compounded additives to improve impregnation are now on the market and can be used to impregnate suitable reinforcements to result in high-temperature mechanical properties (Table 2.33). 

Bismaleimides (BMI) are formed from methylene dianiline and maleic anhydride. They are laminating resins that prepreg well and can be produced on conventional... 

As previously stated, bismaleimides are crystalline compounds with melting points in the range 100-210°C. A few examples are given in Table 4 which provides the melting temperatures T, the maximum temperatures of the exothermic peak and the polymerisation enthalpies AH. Diamines based on 4,4 -methylenebisbenzeneamine carrying methyl and ethyl substituents exhibit melting points around 250°C, while the only bismaleimide melting at about 100°C is the compound obtained from the reaction of maleic anhydride with 6-amino-1-(4-phenyl)-1,3,3-trimethylindane. 

There are two resin systems in common use for higher temperatures, bismaleimides and polyimides. New designs for aircraft demand a 177°C (350°F) operating temperature that is not met by the other common structural resin systems. The primary bismaleimide (BMI) in use is based on the reaction product from methylene dianUine (MDA) and maleic anhydride bis (4 maleimidophenyl) methane (MDA BMI). 

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