The mechanism and kinetics of the ring-opening polymerization of tetrahydrofuran (THF) were studied. The initiating behavior of epichlorohydrin (ECH) in this polymerization was elucidated by examining the products formed in the early polymerization mixture treated with sodium methoxide. It has been shown that the cationic ring-opening of ECH in the presence of THF constitutes the initiation reaction, in which cyclic trialkyloxonium ion, L-O-CH (CH₂Cl) CH₂+O, is formed. This finding is consistent with the concept of “promoter” which has been proposed for the initiating behavior of reactive small-ring compounds. The effect of the nature of initiator on the rates of elementary reactions in the THF polymerization was investigated on the basis of the determination of the concentration of propagating species [P*] in polymerization. A new method, the phenoxyl end-capping method, has been presented for the direct determination of [P*], which can be applied not only to living polymerization system but also to non-living polymerization system. On the basis of time- [P*] relationships, the rate constants of propagation reaction for various initiators were determined. An important conclusion is that the propagation rate is little affected by the nature of initiator, i. e., by the nature of counter anion, whereas the rates of initiation and termination is much dependent on the initiator. The [P*] determination by the phenoxyl end-capping method is also conveniently applied to the selection. of initiator of the living Polymerization of THF in the block copolymerization of THF with 3, 3-bis (chloromethyl) oxetane.

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The glass transition temperature (Tg) of polystyrene in polystyrene (PS) -polybutadiene (PBD) blends consisting of two separate phases was found to shift to the higher temperature than that of pure polystyrene.
The similar phenomenon was observed also in PS-styrene·butadiene rubber (SBR), PSacrylonitrile·butadiene rubber (NBR), PS-polyvinylacetate (PVAc), PS-vinylacetate-vinylchloride (VAc/VC) and PS-polyvinylcholoride (PVC) blend systems.
The larger the difference between thermal expansion coefficient of suspended particles and thermal expansion coefficient of suspending medium (polystyrene), the larger the degree of rise of Tg of polystyrene. The rise of Tg of suspending medium in the blend systems mentioned above was observed in polymethylmethacrylate (PMMA) -SBR, PVC-SBR and styrene·acrylonitrile copolymer (St/AN, AN; 25%) -PBD blend systems. The rise of Tg of suspending medium in the blend systems mentioned above was observed in polymethylmethacrylate (PMMA) -SBR, PVC-SBR and styrene·acrylonitrile copolymer (St/AN, AN; 25%) PBD blend systems. The degree of rise of Tg of PS, PMMA, PVC and St/AN copolymer (AN; 25%) differed mutually. This rising phenomenon of Tg was qualitatively explained by the concept of thermal stress, that is, the rise of Tg of suspending medium was caused by the thermal stress due to the difference of both polymers and the degree of rise of Tg differed in compliance with the potentiality of relaxation of the thermal stress of suspending medium. However, several fundamental questions can not be explained by this concept.

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In order to investigate the mechanism of the crosslinking reaction of oil-modified phenolic resin, the degree of swelling, the tensile force of swollen specimens, and the dynamic modulus in rubbery region were measured on cured films baked for 10minutes in the temperature region from 170°Cto 240°C.
Especially, the composition dependence, baking temperature dependence of the degree of cosslinks and the interaction parameter μ in Flory-Huggins equation were investigated in detail.
It was found that the physical network did not strongly influence the measurement of the crosslinking reaction obtained by the dynamic method proposed by us and the crosslinking reaction could be distinguished into two reactions. i. e., R-1 in lower temperature region below 200°C and R-2 in higher temperature region above 210°C.
The value of the interaction parameter μ seemed to depend on the weight fraction of phenolic resin and on the mechanism of the crosslinking reaction. The information about the interaction parameter μ enabled us to presume the mechanism of the crosslinking reaction concerned with the phenolic resin is as follows:
i) R-1 in lower temperature region below 200°C
A phenolic resin molecule combines with the main chain to make the small side chain. The phenolic resin molecule combined with the main chain combines again with another main chain to make the crosslinking site.
ii) R-2 in higher temperature region above 210°C
A phenolic resin molecule forms the crosslinking site in the same way as in R-1 but in shorter time. Moreover, the phenolic resin molecule formed the crosslinking site combines rapidly with neighbouring main chains conquering some hinderances to increase the degree of crosslinks.

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In order to confirm the varidity of the hypothesis proposed by Keith et al. for spherulitic crystallization in the blend of crystalline and amorphous polymers in relation to crystallization kinetics, isothermal crystallization of the mixtures of fractionated isotactic polypropylene and atactic polypropylene with low and high molecular weights was studied by dilatometry as functions of the composition and crystallization temperature Tc, and the resultant textures were examined by electron microscopy. The electron microscopy revealed that spherulitic skeleton was formed in the very early stages of crystallization and the spherulite became compact from its center through crystallization within the spherulite. In spite of this rejection of the amorphous polymer from the lamellae within the spherulite, the over-all crystallization exhibited the Avrami-type kinetics. This seems capable of being accounted for by applying the Avrami's assumption to the lamellae within the spherulite, rather than to the impingement of the spherulites themselves and assuming that the rate of crystallization is proportional to the concentration of crystallizable molecular species around the lamellae, provided that the effect of the depression of the melting point in the molten phase is small, which was confirmed in this case. The Avrami's exponent was 2.5-3.0, suggesting the heterogeneous nucleation and two-dimensional growth of the lamellae. The logarithm of the over-all rate of crystallization decreases linearly with Tm/ΔTT (Tm: the equilibrium melting temp. and ΔT: the undercooling), which was explained assuming that the primary nucleus may have loose loops so that their end surface energy is small. The eqilibrium crystallinity increased with the content of atactic polypropylene, indicating that the polymer diluent can enhance the crystallinity.

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Acetoacetylated nylon 6 fibers (the degree of acetoacetylation: 3.41%, 3.79%, 7.20%) which were prepared at room temperature in hexane with no catalyst by the reaction of nylon 6 fiber with diketene, were chelated by dipping in aqueous solution of CaCl₂, ZnCl₂, ZnSO₄, AlCl₃, Al₂ (SO₄) ₃, CoCl₂ and CoSO₄. The degree of chelation was not so high. The chelated fibers retained considerably high tensile strength and elastic recovery, but Young's modulus decreased to about an half of the original fiber.
Acetoacetylated nylon 6 cloths (the degree of acetoacetylation: 2.23%, 4.94%, 6.92%) prepared by the above method, were also chelated in the salt solution. The highest degree of chelation was obtained in the case of CaCl₂. The cloth which was 23% chelated in CaCl₂ solution after 2.23% acetoacetylation, had best antistatic property, and showed electrical resis- tance of the surface leakage of 2×10₁₂Ω, which was about 1/35 of untreated nylon cloth, and also showed half decay time of static charge of one second after fi st washing, which was about 1/50 of untreated nylon cloth. Chelated cloths showed better antistatic properties than untreated nylon cloth.

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Various unsaturated polyesters were prepared from maleic anhydride, isophthalic acid, adduct of alkylene oxide with bisphenol-A, hydrogenated bisphenol-A and trimethylol propane, These polyesters were copolymerized with styrene. The tensile strength and elongation of the cured resins were measured over the range from room temperature to 120°C. The relations between chemical structures and the tensile properties are discussed. The experimental equations previously proposed hold to these resins.

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Cationic copolymerizations of styrene (M₁) and eleven benzaldehyde derivatives (M₂) were carried out using BF₃OEt₂ catalyst at 0°C. Benzaldehydes used included ortho-substituted monomers (substituent: CH₃O, Cl, NO₂ and OH), meta-substituted monomers (substituent: NO₂ and CH=O) and para-substituted monomers (substituent: CH₃O, CH₃, Cl, NO₂ and CH=O) The content of substituted benzaldehyde units in copolymer did not exceed 50mol% in all cases, even at high benzaldehyde contents in the monomer feed.
The copolymerization of styrene with p-methoxybenzaldehyde or p-chlorobenzaldehyde gave the following reactivity ratios: r₁=0.10±0.02, r₂=0.01 (styrene-p-methoxybenzaldehyde); r₁=0.45±0.08, r₂=0±0.02 (styrene-p-chlorobenzaldehyde). The remaining r₁ values were estimated by assuming that the r₂ values under the present polymerization conditio s were zero.
It was concluded that the relative reactivities of para-substituted benzaldehydes (M₂) to styryl cation (M₁+) varied depending on the basicity of the carbonyl oxygen.
The r₁ values of the ortho-substituted benzaldehydes except for salicylaldehyde were close to those of the corresponding para-isomers. This suggested that the reactivities of these ortho-isomers depended mainly on the electronic effect of substituents and their steric effect of substituents and their steric effect were insignificant.

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Cationic copolymerization of cyclic phosphonite and various lactams has been carried out in order to obtain a flame-resistant polyamide. The following monomer combinations of cyclic phosphonite and lactam were investigated: ethylene phenyl phosphonite (EEP), ethylene ethyl phophonite (EEP), ethylene methyl phosphonite (EMP), α-pyrrolidone, ε-caprolactam, ζ-enantholactam, ω-laurolactam. The copolymerization was carried out in the presence of various Lewis acids or organometallic compounds as catalyst. The catalytic activity of AlEt₂Cl and AlCl₃ was relatively high among these catalysts. The copolymer compositions of ε-caprolactam or ζ-enantholactam with EPP or EEP were almost the same as the monomer composition in the feed, while the composition of the ω-laurolactam copolymer showed a marked difference from the composition of ε-caprolactam or ζ-enantholactam copolymers and the content of the EEP unit in the copolymer increased. The copolymer had lower melting points than those of the par nt polymers with a poor thermal stability and they burned slowly with a flame resistance. The copolymerization behavior of cyclic phosphonite and lactam was discussed in terms of the reactivity of the amide group of lactam.

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The γ-ray induced bulk polymerizations of 3, 4, 5, 5, 5-pentafluoropentadiene-1, 3 (PFP) and 2-methyl-3, 4, 5, 5, 5-pentafluoropentadiene-1, 3 (MPFP) were investigated in the temperature range from +25 to -196°C. PFP was polymerized both in the liquid and solid states and the structures of the resulting polymers was found to be 1, 4-units. The intrinsic viscosity of the polymer obtained in the liquid state polymerization was considerably higher than that in the solid state polymerization. Poly-MPFP having 1, 4-structure was obtained only in the liquid state polymerization and its rate was about one-tenth of PFP. These results suggest that 2-substituted methyl group in pentafluoropentadiene presumably reduces reactivity due to the steric effect.

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