Photosensitized polymerization of methyl methacrylate (MMA) in the presence of poly (3-methy1-3-butene-2-one) (PMIK) was carried out by the 313 nm photoirradiation. The polymerization was initiated by radicals formed by a-cleavage reaction via excited triplet state (T₁^*) of the carbonyl group. The T₁^* in PMIK was quenched by MMA, the quenching rate determined (k_qτ) being 0.3dm³ mol^-1. The photosensitized polymerizations of MMA in the presence of 3, 3-dimethyl-2-butanone, a model compound of PMIK, and poly (3-butene-2-one) (PMVK) were also carried out. The results obtained were compared with those obtained in the presence of PMIK. Quantum yield for α-cleavage reaction of PMIK could be estimated to be (2.0±0.5) ×10^-1.

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Thermal behaviors of polyether-polyester elastomers (polyether-polyester block copolymers) prepared by polyoondensation were investigated by differential scanning calorimetry. Glass-transition temperatures (T_g), cold crystallization temperatures (T_ce), and melting temperatures (T_m) of hard (polyester) and soft (polyether) segments were measured to discuss the influence of the interaction between the two segments on the crystallization of each segment. Samples with various crystallinities were prepared by cooling from the melt at different rates.
T_g of the samples appeared to rise somewhat with increasing the hard segment content because of the effect of anchoring the ends of the soft segment by being attached to the hard segment. The rise of T_g of samples prepared by quenching from the melt was due to the mixing of extended hard segment with the soft segment phase. The phase mixing caused T_g to rise and was able to impede the soft segment crystallization, thus there were no melting endotherm and cold crystallization exotherm of the soft segment.
The decrease of cooling rate improved the degree of phase segregation and resulted in the drop of T_g owing to the abatement of the interaction between the two segments.

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Photodegradation of a medium-pressure polyethylene exposed in a weathermeter has been investigated from the changes in yield strength and elongation and in molecular weight and molecular weight distribution. The polyethlene containing no UV absorbent was degraded predominantly by crosslinking at the initial stage and subsequently by the chain scission, whereas the polyethylene containing a UV absorbent was by the scission. Elongation decreased remarkably for polymers of M_w less than 2×10⁵. This is due to the decrease in the number of entanglements by the scission.

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Anionically highly reactive α-cyanoacrylic esters were copolymerized with various monomers under the conditions of radical polymerization. About 10 mol % of acetic acid based on the cyanoacrylate was used as the inhibitor for anionic polymerization. Some electron-donating monomers, such as styrene, vinyl ethers, and α-methylstyrene, initiated the copolymerizations spontaneously even at low temperatures. The copolymerizations with many electron-accepting monomers, such as methyl methacrylate, ethyl α-chloroacrylate, acrylonitrile, isobutene, and vinyl acetate, were initiated with α, α′-azobisisobutyronitrile. Radical nature of the spontaneous copolymerization was confirmedby terpolymerization of ethyl α-cyanoacrylate, styrene or isobutyl vinyl ether, and methyl methacrylate or ethyl α-chloroacrylate in the absence of the initiator at 0°C. The compositions of the terpolymers agreed with those calculated from the combination of the monomer reactivity ratios for the individual binary copolymerizations. Relative reactivities of the various monomers toward poly (α-cyanoacrylate) radical calculated from the monomer reactivity ratios were accounted for by the polar and resonance effects of the substituents. As expected from electron-withdrawing character of the cyano and alkoxycarbonyl groups, poly (α-cyanoacrylate) radical was highly electronegative.

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N, N′-Bismaleimido-3, 3′-diphenylalkylphosphine oxide (I) was prepared from bis (3-aminophenyl) -alkylphosphine oxide and maleic anhydride. I and aromatic diamines were used for the synthesis of polysuccinimide-amines containing phosphorus atoms in the main chain. The conditions of the polyaddition and the properties of the resulting polymers were investigated. The polymers were obtained in about 70% yield except in the case of using 4, 4′-diaminodiphenyl sulfone as aromatic diamine. The reduced viscosities of the polymers measured at a concentration of 0.2g/dl in DMA at 30°C were 0.16-0.34. Most of the polymers were soluble in dipolar aprotic solvents, m-cresol, and concd. H₂SO₄. The reduced viscosity of the polymer in concd. H₂SO₄ decreased gradually. The phosphorus-containing polysuccinimide-amines had poor thermal stability in comparison with the polyimides having aromatic imide rings such as phosphorus-containing polyamide-imides and polyester-imides. The polymers were self-extinguished immediately when a flame was removed.

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Flame-retardant action of decabromodiphenyl oxide (DBDPO) on polystyrene (PS) was studied, and compared with the actions of poly (vinyl chloride) (PVC) and cupric halide (CuX₂). Flame-retardant effect of DBDPO on PS was large, while those of PVC and CuX₂ were small. In the case of DBDPO, some bromo compounds remained in condensed phase during burning and decreased the rate of supply of flammable materials to flame zone by inhibiting thermal oxidative degradation of PS near burning surface. On the other hand, PVC and CuX₂ did not show this inhibiting action. The flame-retardant action of DBDPO was attributed to inhibition of thermal oxidative degradation in condensed phase.

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Surface tension (γ) of poly (alkylene isophthalate) s with methylene sequence of various length m (carbon number) was measured with sessile bubble method at various temperatures. An equation relating γ to m and its approximate equation were derived from the Sugden's equation by assuming the additivity of parachor (P) and molecular volume (V). They were examined by the experiments and found valid over the range of m≤10. The deviation, when m>10, underward from the straight line which was expected from the theory was explained by the selective adsorption of the methylene sequences with high chain flexibility which increased with increasing m. The value of γ^d scarcely varied with m, being nearly the same as γ for polyethylene, while γ^p decreased with the increase of m, reaching to zero at infinite m. The equation derived for specific volume was confirmed over the whole range of m.

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The polymerization of β-propiolactone (β-PL) and acrylic acid (AA) by propionaldoxime (POM) has been studied. Both polymerizations proceeded by anionic mechanism. The molecular weight of resulting polymers was in the range of 1, 000 to 2, 000 [poly (β-PL)] and ca. 1, 000 [poly (AA); vinyl polymer]. Catalyst POM was efficient to give acrylic acid oligomer. From the results of equimolar reactions of POM with β-PL and AA, it was confirmed that the initiating species in the polymerizations of β-PL and AA are anions, CH₃-CH₂-CH=N-OΘ and CH₂=CH-COOΘ respectively.

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