The author has investigated various factors which are supposed to effect stress cracking of polycarbonate, such as annealing, plasticization, uniaxial stretching and molecular weight. The results are as follows: 1) annealing is effective within certain limits; 2) addition of plasticizers decreases stress cracking resistance; 3) stress cracking resistance increases in the direction of orientation and decreases perpendicular to the direction of orientation; 4) the higher is the molecular weight, the higher becomes the stress cracking resistance.

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Crazing polycarbonate has been investigated from the observation of craze pattern, microscopic observation, and measurement of yield strength as to whether “craze” in amorphous polymer is “orientation”or “crack”. The author has come to conclude that crazing in general amorphous polymer is a different phenomenon from cracking; it is not “crack” but “orientation”. With simulation of amorphous polymer by entangled threads, phenomenon of crazing has been explained.

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When a film adhered on rigid surface is in the peeling equilibrium, then the work of adhesion W is given by the equation, W=P (1-cosθ), where P is the peeling force per unit width and θ the peeling angle. This theoretical equation is examined experimentally in this study for polyisobutylene-glass and polyvinylacetate-glass systems.
From the results of experiment over a wide range of peeling rate (10^-5-1cm/sec), it is shown that the equation is valid at such small rate that the theoretically assumed equilibrium condition seems to be established. At larger rate the peeling force increases considerably and does not fit to the above equation.
Considering the work of elongation of stripped film due to this force, the following equation is derived.
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where W_a is the specific work of adhesion, λ the extension ratio, t₀ the thickness of the film, and E the Young's modulus. Taking E (or λ) and W_a as experimental parameters, this equation reproduces all experimental results satisfactorily. However, the given values of E and W_a are dependent of peeling rate, and the reason for it is not clarified by this static treatment.

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To study the rheological character of peeling, peeling force and rate are measured at different temperatures for plasticized vinylite films casted from solution on glass plates. Logarithmic plots of the peeling strength vs. the peeling rate give the typical S-shaped curve for each specimen of different content of plasticizer (DBP, 0-40%) and at each temperature above the glass transition temperature. The time-temperature superposition principle is established for the peeling strength, and the shift factor, a_T, satisfies the WLF equation log a_T=-8.86 (T-T_s)/(101.6+T-T_s). However, the reference temperature, T_s, in this equation does not obey the empirical rule T_s≈T+50°C, but gives much lower values. Therefore, calculated values of fractional free volume (0.037-0.040) are higher than the known value of 0.025. This result is illustlated by the theory of Ferry and Stratton. The apparent activation energies at T_s are varying in the range 46.5-33 kcal/mol with the content of plasticizer. It is concluded from these results that the dependence of peeling strength on rate is essentially due to the rheological behavior of polymer films, and there is no need to introduce a new interfacial force, such as electrostatic force proposed by Deryagin.

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Radical polymerization of β-allyloxyethyl acrylate was carried out in benzene at 50°C or 60°C. The relationships between initial concentrations of the monomer and limitting viscosity numbers [η] of the initial polymers, conversions and [η] of the polymers, initial concentrations of the monomer and gel-points, initial rates of polymerization and initial concentrations of the monomer or the initiator, and initial concentrations of the monomer and compositions of the polymers were interpreted by assuming the mechanism of cyclopolymerization.

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The influence of the distribution ratio of unsaturated acids between methyl methacrylate (MMA) phase and water phase on the copolymerization of MMA-unsaturated acids and on various properties of the obtained emulsion particle has been investigated. Acrylic acid (AA) had the lower value of distribution ratio (70°C, 1.41), which indicated that AA was hard to diffuse into the particle and consequently polymerized easily in water phase. The emulsion particle of AA-MMA copolymer had the greater surface charges than that of MAA-MMA copolymer at pH≈7, and was swollen well by water. Otherwise, methacrylic acid (MAA) had the higher value of distribution ratio (70°C, 6.13) than that of AA. This result indicated that MAA diffused easily to the particle and copolymerized well with MMA. Accordingly the emulsion particle of MAA-MMA copolymer was found to have the lower surface charges than that of AA-MMA copolymer.

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N-vinylcarbazole (mp 64°C) was polymerized in the solid phase by the cationic catalyst, such as BF₃ or BF₃0 (C₂H₅) ₂, at 0-55°C. Both the rate and the molecular weight of resulting polymers in the solid phase polymerization were smaller than those in the solution polymerization. In the solid phase polymerization catalyzed by BF₃ gas, the activation energy of overall rate was 11.4±1.5kcal/mol. It was found from X-ray diffraction pattern that the polymer resulting from the solid phase polymerization was amorphous as well as that in the solution polymerization.
Although molecular weight of the resulting polymer in solution polymerization decreased as temperature went up, the molecular weight of polymer obtained in the solid phase polymerization was independent of polymerization temperature. When n-hexane was used as the suspension medium for the monomer crystal or a small amount of n-hexane was contained in the monomer crystal, the rate of polymerization and molecular weight of resulting polymers were larger than those in the polymerization of pure monomer crystal.

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Interfacial polycondensation of terephthaloylchloride and ethylenediamine under the influence of ultrasonic field was studied.
The rate of polymerization and the molecular weight of polyamide thus obtained increased by ultrasonic irradiation. This acceleration effect would be attributable to the ultrasonic cavitation phenomenon, since interfacial polycondensation was accelerated in ultrasonic field of high power enough to arise the cavitation.
Interfacial polycondensation came into effect at the lower ultrasonic frequency in the range of 200-2000kc.
Optimum concentrations of reagents were not effected by the ultrasonic irradiation.

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