A new method for estimating the molecular weight distribution (MWD) by the analysis of diffusion curve of an unfractionated polymer sample has been proposed. First, the sample is divided into n fractions and a set of n diffusion coefficients (designated as D₁ for i-th fraction) are selected from pseudorandom numbers generated in a computer. It is assumed for convenience that the concentration of each fraction (c₁) is equal. Then, by giving these D₁′s and c₁ in the diffusion equation, the diffusion curve of this system is synthesized. If the curve is appreciably different from the experimental curve, a new set of D₁′s are selected and the above mentioned procedures are repeated. The set of diffusion coefficients which give the diffusion curve most closely related to the experimental curve is made to represent the most approximate composition of the sample. This method was applied to the analysis of phenol-urea-formaldehyde resin and the following equation was obtained for the relationship between viscosity-diffusion average molecular weight (M_VDA) and diffusion coefficient (D_A):
M_VDA=0.17×10^-10D_A^-2.5.
By this equation, the diffusion coefficient distribution was transformed into MWD. Then the effects of monomer feed ratio on MWD of the polymer were discussed.

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The addition-condensation reaction of phenol with formaldehyde was studied by utilization of computer simulation, and the dependency of the reactivity on the molecular weight was discussed. At first, both the values of molecular weight and the number of molecules in each fraction which are determined from the analysis of diffusion curves are stored in computer and then two of thesemolecules are selected with a probability (P) which depends on the molecular weight as P∝M^a. A molecule formed by the combination of these two molecules is fed back into computer. Such procedures are repeated. Then the molecular weight distribution calculated from this simulation process is compared with the distribution obtained by the fractional precipitation technique. It becomes clear that, in the hardening reaction of phenol resin, the reactivity is proportional to the molecular weight, that is, a in the above equation is equal to unity. It is also comfirmed that a methylol group in a polymer molecule reacts with one of phenols in the other polymer molecules. The number of phenol unit in a polymer molecule is proportional to its molecular weight.

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The postpolymerization of 2-amino-4-N-methylanilino-6-isopropenyl-1, 3, 5-triazine (AMIT) irradiated in glassy-state with γ-ray of ⁶⁰Co at -78°C was investigated. The DSC of AMIT irradiated in glassy-state showed a glass-transition temperature at 16°C and an exothermic peak due to polymerization at temperature near 41°C. This fact shows that the active species are trapped in the glass without causing polymerization until the glass-transition temperature is reached. The post-polymerization at 30-110°C of samples irradiated at -78°C gave polymers in saturated yields which depend on the polymerization temperature. It is shown by the measurement of ESR spectra and Gordon-Taylor's plot that a cause of the saturation of the polymer yield is not the disappearance of the active species but the glass formation of the polymer and monomer mixture during the postpolymerization.

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The polymerization of p-isopropenyl phenol (IPP) and its copolymerization with various vinyl and diene monomers were investigated at 60°C by using 2, 2′-azobisisobutyronitrile as a radical initiator. IPP, obtained by thermal decomposition of 2, 2-bis (4-hydroxyphenyl) propane, melts at 85°C and is needlelike crystals (from n-hexane). The radical copolymerization was carried out with acrylonitrile, methyl and ethyl acrylates, methyl methacrylate, styrene, isoprene, butadiene, and vinyl acetate. The copolymerization reaction did not proceed in the aerial atmosphere, whereas no induction period was observed in degassed condition. The analysis of copolymer composition showed that the copolymers of IPP with acrylonitrile and methyl acrylate are highly alternating. However, neither homopolymer nor copolymer was obtained from the copolymerization system of IPP with vinyl acetate. From the monomer/copolymer composition curves, the monomer reactivity ratios and Q and e values of IPP were calculated.

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Polymerization of phenyl glycidyl ether (I), a model compound of epoxy resin, by triethanolaminetitanate-triphenyl borate complex II was investigated to elucidate the curing reaction of the epoxy resin with II. The polymerization follows a second-order rate low for I and II. The activation entropy was -56cal·mol^-1·deg^-1 which seems to be a large negative value in the ring opening reaction of epoxide. Infrared spectrum of the system clearly shows the disappearance of B←N linkage at 1380 cm^-1 and the constancy of B-O linkage at 1340 cm^-1 during the polymerization. It is concluded that the ring opening reaction of the epoxide was by a S_N2 mechanism.

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The mode of the interaction between polymers and wood in Wood-Polymer Composite (WPC) was pursued by the dynamic viscoelasticity (E_T′, E_T″) of the following systems: (I) PSt (poly styrene) -WPC prepared by electron beam irradiation and (II) PSt-WPC by injection of high molecular weight (HMW) PSt or low molecular weight (LMW) PSt. The temperature dependence of E_T″ coincided with that of G_L″, and three peaks ((a), (b), and (c)) were recognized. Peak (a) at ca. 230°C was inherent to wood itself. Low temperature shift of (a) with isoelastic point (ca. 225°C) was observed for I with increasing polymer content in cellular parts. Peak (b) was peculiar to II; at ca. 120°C for HMW-II and at ca. 110°C for LMW-II. Peak (c) was separated from the E_T″ terrace (120-200°C) of LMW-II and I at ca. 160°C. Peak (a) wassuggested due to a rearrangement of micro fibrils during thermal degradation by the viscoelastic results in correlation with those of DTA and X-ray studies. (b) was assigned to the interaction between polymer and surface of the cellular parts. (c) was suggested to be augumented by the extreme interaction of polymer with surface of cellular parts in micro voids or cleavages.

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Porous cellulose acetate (I) membrane having a pore opening diameter of 0.01-10 μm and a porosity of 30-85% was prepared by casting a mixture of I having an acetyl content of 54.1%, a metal salt, a good solvent for I, and a poor solvent for I. The metal salt in the film was removed subsequently by dissolving the salt. The metal salt added to the solution plays the following roles: (1) increase the pore density and (2) yield a membrane with round pores at either surface. The fundamental phase-separation characteristics in the membrane forming process were studied systematically by chemical analysis together with microscopic observation. Particles, having a diameter of about 0.05 μm, of a polymer-rich phase, which appeared during the evaporation of solvent, amalgamate in part straightforwardly into a continuous phase (case A) or grow up (ca 2 μm) partly to contact with each other (case B). In subsequent processes of further solvent evaporation, washing and drying, in the case A the continued polymer-rich phase contracts volumetrically, yielding opening pores and in the case B crevice among the grown-up particles becomes opening pores. The occurrence of either case A or case B depends essentially on the composition of solution at the stage that the phase separation starts.

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The γ-ray-induced oxidation of syndiotactic 1, 2-polybutadiene film with the thickness of 15 p was carried out at 30-100°C in air atmosphere. The weight of the film increased linearly with the radiation dose after some induction period. Infrared spectroscopy showed the decrease of vinyl group and the formation of various oxygen-containing groups such as alcohol, hydroperoxide, unsaturated ketone, acid, saturated ketone, aldehyde, ester and peracid groups. Among the carbonyl groups, the saturated ketone group was predominant. In the early stage of the oxidation, the rates of both weight increase and formation of hydroxy and carbonyl groups were found to be approximately proportional to the square root of dose rate. These rates also increased with the increase of irradiation temperature and the apparent activation energies for the formation of hydroxy and carbonyl groups were determined to be 5-6kcal/mol. Further, it was found that post reaction proceeded gradually when the film irradiated at 30°C was kept in air without irradiation. On the basis of these results, the oxidation mechanism was discussed in connection with the cyclization and crosslinking of the polymer.

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For the purpose of obtaining high polymers possessing high thermal stabilities and superior mechanical properties, high molecular weight polymers of general formula,
have been prepared by melt-polymerization of p-bis (phenylaminodimethylsilyl) benzene with various organic diols. The polymers were soluble in organic solvents such as benzene, tetrahydrofuran, and chloroform and possessed film-and fiber-forming properties. Thermogravimetric analyses of the polymers showed that the thermal degradation did not occur at temperatures below 400°C, exhibiting excellent thermal stabilities of the polymers. However, alkali-and water-resistance properties of the polymers were inferior to the polymers consisting siloxane linkage in the main chain. The dielectric permittivities of the polymer containing biphenyl group, and of its charge-transfer complexes with TCNQ and chloranil were measured at room temperature. The increase of dielectric permittivities by complexation was very small.

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The copolymerization of 2, 4-, 2, 5-, 2, 6-, 3, 4-, and 3, 5-dimethylstyrene with styrene was carried out by using a various combination of catalyst (SnCl₄, AlBr₃, TiCl₄, BCl₃, and BBr₃) and solvent (tetrachloromethane, 1, 2-dichloroethane, and nitrobenzene). The reactivity of the monomers was investigated in detail and was found to change in a complicated way by combined effects of various factors such as acidity of catalyst, dielectric constant of solvent and monomer structure.

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A kinetic study was made on the random scission of the carbon chains in the thermal degradation of polymers under an inert atmosphere. The analysis was made under the condition of removing volatile products out of the reaction system by evaporation and an equation was derived to describe the change of polymer weight in the course of the reaction. Equations were also derived for the changes due to the thermal degradation in the molecular weight distribution and the number averaged molecular weight of a polymer with any initial molecular weight distribution. It was particularly found that both the rate of decrease of the polymer weight and that of the number averaged molecular weight are not dependent on the molecular weight distribution of the initial polymer but on the initial number averaged molecular weight and the critical chain length for evaporation. The experimental results of the thermal decomposition of polyethylene under an inertatmosphere were compared with the theoretical calculations derived on the basis of random scissionof carbon-carbon bonds, and the rate constant of the scission at 415°C was evaluated as k=2.8×10^-2hr^-1.

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Radical polymerization of alkyl methacrylates under various conditions was carried out with using various liquid crystals as solvents, and effect of liquid crystalline solvents on the stereospecificity of the resulting polymers has been investigated. Both the yields and solution viscosities of the polymers obatined in liquid crystalline solvents were higher than those obtained in benzene. The length of alkyl chain in the ester group of the methacrylate had a considerable influence on the stereospecificity of the polymers. That is, no difference in the stereospecificity was observed between two kinds of poly (methyl methacrylate) s, one obtained in benzene and the other in liquid crystalline solvents, whereas the polymerization of monomers each of which has a long alkyl group such as n-butyl, 2-ethylhexyl or n-dodecyl yielded the polymers with higher isotactic triad contents in liquid crystalline solvents than the polymers obtained in benzene.

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