The new synthetic routes of a variety of thermally stable polymers were extensively studied. The technical term called “Cyclopolycondensation reaction” was proposed, which involves the formation of heterocyclic ring system in polyaddition and polycondensation reactions. A variety of new heterocyclic polymers such as polyquinazolones, polybenzoxazinones, polyquinazolinediones and ladder polymers were prepared. In particular, the new polymerization process using aromatic diaminodicarboxylic acids as monomer components have been studied in detail, and a variety of new high-temperature plastics for industrial use were synthesized and the evaluation in polymer research and development was carried out. As one class of polymerization reactions, the proton-transfer polymerization of polysulfoneamides and aromatic polyamides was investigated by Michael type addition reaction, and the relation between polymer structure and properties was investigated. The physical properties of the polymers such as thermal stabili y of resultant polymers were determined, and the new polymerization process was established for the synthesis of new type of thermally stable polymers.

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The following six monomers were polymerized using benzoylperoxide as a radical initiator: cinnamic acid (a), ethyl cinnamate (b), ethyl α-ethylacrylate (d), ethyl tiglate (f), N-vinylsuccinimide (i) and citraconic anhydrjde (j). The given polymers except poly- (a) were hydrolyzed to the corresponding polycarboxylic acids.
The following results were obtained in the titration curves and the acid anhydride formation of these polymeric carboxylic acids. Poly- (a) and the hydrolysis product of poly- (b) behaved in a similar way. The hydrolysis product of poly- (j) showed almost the same behavior as those of polymesaconic acid and polycitraconic acid, all composed of the same monomeric units. On the other hand, the behaviors of the hydrolysis product of poly- (f) were distinctly different from those of polytiglic acid. All of the six polymers were stronger acids than polyacrylic acid and polymethacrylic acid.
These results were discussed on the basis of the spacial distance between neighboring carboxylic acid groups in the polymer molecules.

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In order to obtain a basic information on reaction mechanism of heterogeneous polymerization of vinyl monomers in an aqueous medium, the effect of stirring speed on the rate of Polymerization of acrylornitrile was investigated.
The follewing results were obtained: (1) The rate of polymerization of acrylonitrile decreased with the increase in the speed of stirring, but its effect was quite small compared to that of methyl methacrylate which had previously been reported. (2) In the polymerization of acrylonitrile, no parallel correlation was observed between the increasing rate of particle diameter and the rate of polymerization at a particular speed of stirring, and the rate of incremernt of particle diameter increased with the decrease in the rate of polymerization. (3) In the case of acrylonitrile, the particle size distribution broadened with the increase in the speed of stirring, being completely opposite to that of methyl methacrylate. (4) In the case of acrylonitrile, unlike methyl methacrylate, it was observed that the polymer particles was not only grown larger by themselves but also by adhering arnd covering the secondary fine particles generated elsewhere on the surface of the polymer particles. Accordingly, the usual conclusion that the polymerization proceeds exclusively on the surface of polymer particles is doubtful.

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Copolymerization of acrolein (M₁) with methyl acrylate (MA). ethyl acrylate (EA), n-butyl acrylate (n-BA), 2-ethyl-hexyl acrylate (2EHA), methyl methacrylate (MMA) and styrene was studied, and the following reactivity ratios were obtained.
r₁=1.2, r₂=0.6 for MA and EA
r₁=1.6, r₂=0.6 for n-BA and 2EHA
r₁=0.8, r₂=1.2 for MMA
r₁=0.25, r₂=0.25 for styrene
Acrolein alternatively copolymerized with styrene. Q and e values of acrolein calculated from monomer reactivity ratios of acrolein-styrene copolymerization were as follows: Q=0.78, e=0.81.
The rate of copolymerization of acrolein with styrene increased with increasing the concentration of acrolein in monomer mixture and reached a maximum at an acrolein content of 75 mol % in monomer mixture. Cross termination constant φ and δ for acrolein were obtained, φ=1, δ=32.5.

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Thermal degradation of poly (N-phenyl maleimide) was investigated over a range of temperatures from 300 to 380°C under a constant flow of nitrogen. This polymer is stable below 300°C. Above 300°C, chain scission and crosslinkage occur. Main volatile products are N-phenyl succinimide, its dimer or trimer, s-diphenylurea, carbon dioxide and carbon monoxide. A degradation process for this polymer is presented.

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