Studies were made on the crystallization of polyethylene terephthalate (PET) having the inherent viscosity of 0.464 to 0.894.
1) It was found that the lower molecular weight PET showed a higher limiting density after heat treatment at given temperatures ranging from 100°C to 240°C.
2) Sample with the higher degree of polymerization showed the greater induction time of crystallizationand the smaller crystallization rate. These phenomena suggest that the aggregation of chain molecules proceeds more difficultly with increase in the chain length of PET.
3) The course of crystallization at near the lowest crystallization temperature follows Avrami's equation.
The result obtained shows that the values of Avrami's constant n vary from one to three depending upon the degree of polymerization.

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The gels having various permeability limits were studied by infra-red spectra, visco-elasticity, volume swelling and electronmicroscope. The following results were obtained. As the permeability limit was large,
i) Molar ratio of divinyl benzene in styrene-divinyl benzene copolymer increased.
ii) Crosslink density and glass transition temperature increased.
iii) Ratio of volume swelling in toluene (solvent) and methanol (non-solvent) approached to one, but the ratio of diluent to monomer in the polymerization was maximum at 10⁴ Å gel.
iv) The pore size in the gel increased.

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The calibration curve for gel permeation chromatography and weight average molecular weight by light scattering were determined with the fractionated samples obtained from the commercial polystyrene. We found the linear relationship between log [η] or log M_w and counts of elution peak. Using the above calibration curve we studied the molecular weight and molecular weight distribution of the commercial polystyrene and the result of GPC by area method was good consistent with that of column chromatography. Wesslau and Tung methods have been applied to the fractionation data and the latter was more preferable than the former.

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A parameter of Barus effect D_j/D₀, post extrusion swelling, was measured at various temperatures, for concentrated solutions of acrylonitrile-methylacrylate copolymer having different molecular weight in different polymer concentration.
The experimental results show that (D_j/D₀) decreases with increasing capillary length. This fact indicates that the degree of elastic deformation which have been imposed at the inlet of capillary decreases with increasing the residence time of concentrated solution in capillary.
(D_j/D₀) of various kinds of samples, which still exists after long residence time in capillary, plotted against log P₁₁ falls on the same line within experimental errors. Where P₁₁ is normal stress measured by capillary method. Therefore, it can be considered that (D_j/D₀) which still exists after long residence time depends on P₁₁ rather than molecular weight of polymer sample, polymer concentration, and extrusion temperature.

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Elastic modulus of the crystal lattice parallel to the chain axis (E_l), for isotactic polybutene-1 (Isot.PB) was determined by an X-ray diffraction method. The modulus was found to be Isot. PB: E_l=25×10⁴kg/cm² (25±1°C).
Natta et al. reported that the chains of Isot. PB assumed the conformation of a three-fold helix in the crystalline state.
The above E_l-value for Isot. PB was discussed in terms of the force required to stretch a molecule by 1% and was compared with the E_l-values for isotactic polypropylene, isotactic polybutene-1 and isotactic polystyrene which also assumed the same conformation of the chain skeleton as Isot. PB in the crystalline state.

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The effects of mixing condition and polymer ratio on the impact strength behavior of the polyvinyl chloride-polybutadiene-ABS resin system were studied under electron microscope. The impact strength of PVC was shown to be synergistically improved by blending polybutadiene together with ABS, the optimum dispersed particle size of the rubber being 0.8-1.0μ. These results were presumed to arise from the change in the size of dispersed rubber particles in the continuous polyvinyl chloride phase.

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Two modelsc oncerningth e positiona nd the velocityo f scissiona ccordingto the result of previous paper (formula 1), are pressented for cosiderations.
1) Each linkages in the polymer of the same degree of polymerization having no individuality, otherwise in the different degree of polymerization.
2) The reaction (scission) constant different as to individual linkage in main chain counting from the each ends of polymers.
Individual approximate equations of the distribution of degree of polymerization after degradation for these models are established.
At earlier state of degradation which is expressed by the equation of random type scission roughly, the following equation is derived approximately.
where;
(ν: number of scission points of the largest molecule)
τ=k₀c (k₀, c: defined in the previous paper)
N_ξ=number of ξg-mer. g is the minimum degree of polymerization of degradation reaction.
₀N_ξ=number of ξg-mer produced by random scission (scission constant=k₀)
Δk_ξ^ε=deviation of scission constant of the ξg-th linkage counted from the end of molecule of k g-mer, from k₀.
The result of the calculation for the model 1) and 2) are different, especially in the regions of low molecular weight.

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After the mixture solution containing ceric salt, acrylamide monomer (AM) and HNO₃ was stored for a given time in air, a given weight of gel-cellophane was introduced in the system, and then the graft copolymerization was carried out.
The behavior of grafting reactivity was found to change by the storage time and also the grafting yield was affected by some factors such as HNO₃ concentration, cellulose concentration and dissolved oxygen content.
At the low concentration of HNO₃ such as 7.5×10^-3mol/l, the induction period was appeared and it was recognized to shift to the short time duration as the storage time raised, and the grafting yield increased proportionally to the reaction time. At the high concentration of HNO₃ such as 3.0×10^-2mol/l, the induction period disappeared and the grafting yield was found to reach the constant level within a short reaction time. The grafting yield increased as the cellulose concentration and the dissolved oxygen content increased.
On the basis of the results obtained here, the initiation of graft copolymerization was presumed to be affected by both the action of Ce^IV and cellulose, and the action of activated (Ce^IV-AM) complex.
Further, the effect of HNO₃ concentration, cellulose concentration and dissolved oxygen content were studied on the behaviour of (Ce^IV-AM) complex formation.
By considering on the behaviour of grafting and (Ce^IV-AM) complex formation during the reaction, the grafting reactivity was presumed to be affected by both the behavior of formation process and decomposition process of (Ce^IV-AM) complex.

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The effects of model compounds of cellulose were studied on the AM monomer conversion during the reaction.
The model compounds used here were alcohol (n-butanol, propylene glycol), monosaccharide (β-glucose), disaccharide (saccharose) and polysaccharide (starch).
In the case of starch and cellulose, the AM monomer conversion increased with the storage time of “Ce^IV-AM-HNO₃” system, but the opposite results were obtained in the case of other compounds.
From these results, this grafting mechanism was presumed to be not understood as the usual mechanism by OH group or the dependency of homogeneous or heterogeneous system.
Further, the effects of e-value of monomer were studied on the grafting.
In the case of monomers such as acrylamide and acrylonitrile having the higher e-value, the grafting reactivity against the storage time of “Ce^IV-monomer-HNO₃” system was prolonged and [Ce^IV-monomer] complex was found to be formed easily. In the case of monomer such as N-vinylpyrrolidene having lower e-value, the graft copolymerization and the formation of complex were not detected.
On the basis of the results obtained here and the results in the previous papers of this series, the grafting mechanism was presumed to be affected by the reactivity of [Ce^IV-monomer] complex.

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Partially acetylated polyvinyl alcohols (Ac-PVA) were hydrolyzed with polystyrene sulfonic acid or partially sulfonated polystyrene in aqueous solutions, and the rate constants of hydrolysis (k_s) were compared to those of hydrolysis carried out under the same condition with hydrochloric acid (k_HCl). Generally the ratio γ=k_s/k_HCl was much greater than unity, considerably dependent on acetylation degree, distribution of acetyl groups, the steric configuration and concentration of Ac- PVA, but only slightly dependent on the polymerization degree of the polymer. The γ-value was also affected by reaction medium and temperature. The fact that the γ-value is greater than unity may be explained by an increase of concentration of the sulfonic acid groups in the neighborhood of Ac-PVA molecules due to hydrophobic binding of the polymer catalyst and the polymer ester.

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Partially acetylated polyvinyl alcohols of different degrees of acetylation were hydrolyzed with various polymeric sulfonic acids in aqueous solutions, and the rate constants of hydrolysis (k_s) were compared to those of hydrolysis carried out under the same condition with hydrochloric acid (k_HCl). The ratio γ=k_s/k_HCl was dependent not only on degrees of sulfonation but also on preparation conditions of sulfonated polystyrene and polystyrene sulfonic acid. The effect of polymerization degree of these sulfonic acids on their catalytic action was slight. The polymer sulfonic acids containing highly hydrophobic groups showed much greater γ-values than unity, but the order of γ-values could not be explained only by the hydrophobic nature of the polymers. Some discussions were given for the results.

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Partially acetylated products of branched polyvinyl alcohols (PVA)(branched units<1.3/100 unit molecules), vinyl alcohol-allyl alcohol copolymers (mol% of allyl alcohol<22) and vinyl alcohol-isopropenyl alcohol copolymers (mol%of isopropenyl alcohol<18) were hydrolyzed with polystyrene sulfonic acid, partially sulfonated polystyrene and dodecylbenzene sulfonic acid in water, and the rate constants of hydrolysis (k_s) were compared to those of hydrolysis carried out under the same condition with hydrochloric acid (k_HCl). Generally the values of =γk_s/k_HCl for acetates of these modified PVA were near those for acetates of linear unmodified PVA. Partially acetylated starchs were also hydrolyzed, and it was found that the γ-values were much smaller than those for partially acetylated PVA of the same acetylation degree. The γ-value for partially acetylated amylose was somewhat greater than that for partially acetylated amylopectin. Some discussions were given for these results.

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The copolymerization of N-carbamyl-maleimide with styrene was carried out in benzene at 70°C, and the copolymers were pyrolyzed in dioxane at 100°C. From the studies on IR spectra and elementary analyses of the pyrolyzed copolymers, it was found that the pyrolyzed copolymers consisted from styrene units (50-80mol%), maleimide units (5-30mol%) and maleamic acid units (10-40mol%).

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Divinyl-n-butyral and vinyl formate were synthesized and polymerized under the various condi tions in the presence of radical initiators. Infrared spectra (IR-S) of polyvinyl alcohols (PVA) derived from the polydivinyl-n-butyrals (PVB) were nearly the same on each other, but consider ably differed from that of usual PVA. IR-S of polyvinyl acetates (PVAc) derived from PVB's were almost consistent with that of usual PVAc. Polyvinyl formates (PVF) and PVA'sderived from them showed nearly the same IR-S as the usual polymers, respectively. Acetalization ratesof PVA's derived from PVF's were similar to that of usual PVA, but PVA's derived from PVB's showed the much lower acetalization rates. Furthermore, hydrolysis rates of PVAc's derived from PVF's were nearly the same as that of usual PVAc, but PVAc's derived from PVB's showed the fairly different hydrolysis rates. From these results it seems that the steric structures of PVA's derived from PVB's are similar to each other, but considerably differ from that of usual PVA, and PVA's derived from PVF's have the similar steric structures as the usual one.

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Terpolymerization of vinyl chloride (M₁) and propylene (M₂) with other vinyl termonomers such as acrylic acid (M₃), methyl methacrylate, methyl acrylate, styrene and acrylonitrile was studied in benzene solution at 50°C, using azobisisobutyronitrile as initiator.
It was found that in all cases termonomer was predominantly incorporated in the terpolymer formed. From the copolymerization of propylene with acrylic acid, monomer reactivity ratios were determined at 50°C as follows:γ32=9.7, γ23=0

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