Jerry E. White

Polymerization of N,N'-bismaleimido-4,4'-diphenylmethane with arenedithiols. Synthesis of some new polyimidosulphides

Abstract Two new polyimidosulphides were prepared in 94% yield or higher and with inherent viscosities as high as 1.45 dl g −1 (0.5 g polymer/100 ml dimethyl sulphoxide; 25°C) by the addition of 4,4′-dimercaptodiphenylether or 4,4′-dimercaptobiphenyl to N , N ′-bismeleimido-4,4′-diphenylmethane. Formation of soluble species requires a solvent that is or contains a proton source, since crosslinked products results otherwise. The polymers are amorphous thermoplastics with rigid backbones, reflected by their high glass transition temperatures ( T g = 185°–212°C) as well as by their insolubility in all but highly polar media, such as dimethyl sulphoxide of N , N -dimethylformamide. Both polyimidosulphides, when heated under nitrogen or air (thermogravimetric analysis), show no weight loss up to about 350°C, but the polymers degrade catastrophically (apparently via base-catalysed thiol elimination) within minutes at room temperature when dissolved in aprotic solvents containing secondary or tertiary amines.

Poly(hydroxy ether sulfonamides). A new class of epoxy‐based thermoplastics

Base-initiated polymerizations of N,′N-dimethyl-1,3-benzenedisulfonamide or other N,′N-dialkyldisulfonamides with various arylene-diglycidyl ethers afford a broad range of poly(hydroxy ether sulfonamides) (2). Polymers 2, which represent a new family of epoxy-based thermoplastics, are moldable, amorphous materials characterized by moderate Tg (58–127°C) and by good barrier to oxygen, reflected by oxygen transmission rates of 0.45–2.89 cc-mil/100 in2-atm (O2)-day at 234 °C and about 60% relative humidity. In addition to a discussion of how structural changes in the backbones of 2 influence their barrier properties, details of the synthesis, thermal analysis and mechanical evaluation of the polymers are described.

Thermally stable, photoactive polymerizable diazenes. Applications in polymer technology

New and useful nonpolymerizable and polymerizable diazene free radical initiators have been designed, based on molecular orbital and empirical linear free energy calculations. The design of the polymerizable diazenes has been based on four requirements: independent reactivities of azo and vinyl moieties, high thermal stability of the trans-diazene isomers, efficient convertability of the trans isomer to the cis isomer, and high thermal reactivity (to produce free radicals) of the cis-diazene isomers. The cis-diazene isomers are obtained from the trans isomers by irradiation with visible light. A new free radical initiator has been shown to be useful in preparing graft copolymers and in crosslinking polymer chains by visible light activation. Poly(styrene-co-2-(meta-styrylazo)-2-methoxypropane) (2) was prepared by the copolymerization of styrene monomer and 2-(meta-styrylazo)-2-methoxypropane (1), either thermally or via a free radical initiator. Copolymer 2 then was reacted with methyl methacrylate monomer in the presence of visible light, to produce poly (styrene-g-methyl methacrylate) (6). Poly(styrene-co-2-(meta-styrylazo)-2-methylpropane) (17), prepared by the copolymerization of styrene monomer and 2-(meta-styrylazo)-2-methylpropane (15), was successfully crosslinked at elevated temperatures.