The present status of physico-chemical investigations of dilute aqueous solutions of synthetic and biologically important polyelectrolytes was briefly reviewed. It was pointed out that the mean activity coefficient of the solute obeys the cube-root rule in contrast with the square-root dependence found for simple electrolyte cases. This difference was attributed to intermacroion attractive forces originated from strong attractive forces between macroion and gegenions. Furthermore, it was pointed out that a widely accepted assumption pertaining to the liquid junction potential, which is an unavoidable premise of the experimental determination of the single-ion activity, is not valid for polyelectrolyte solutions. From this, it is clear that various conclusions obtainable, for example, from the potentiometric titration should be viewed with great caution. The second virial coefficient for ternary systems, water-polyelectrolyte-simple electrolyte, was obtained from the mean activity coefficient and found to be in good agreement with the value determined by an independent method. The hydration number of various macroions was determined from the partial molar volume, which is a pressure derivative of the mean activity coefficient, and discussed in terms of the electrostrictional hydration and the ice-berg structure promotion around hydrophobic parts of macroions. It was inferred that the solubility of hydrocarbon in water should be influenced by the ice-berg forming tendency of the macroion: in fact the solubilization phenomenon of naphthalene by polymer addition was observed. From the transference measurements, the gegenions were concluded to be fixed outside of the hydration shell of macroions. Finally, polyelectrolytes displayed distinct acceleration effects on reactions between likely charged ionic species. This was found to be due to the enthalpy change caused by polyelectrolyte addition, but not due to enhancement of the collision frequency of reactant ions, contrary to the usually accepted view. The implication of this conclusion was noted in connection with catalytic actions of DNA and RNA.

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The deformation and orientation in the melt spinning process of nylon 6 were studied by measuring the temperature, diameter, yarn tension and birefringence of running threadline at various points from the die operating under several spinning conditions.
The result is summarized as follows.
1) Deformation of the thread-line depends little on the initial temperature and molecular weight of the polymer, but is much affected by the rate of extrusion and take-up velocity.
2) The Trouton viscosity for nylon 6 is expressed by the following equation, where T is the absolute temperature.
β=0.34exp (3250/T)
3) The value of β for nylon 6 is larger than those for polypropylene and polyester in the same range of temperature and molecular weight.
4) The cooling curve of the thread-line derived from the numerical calculation agrees well with the experimental results.
5) The orientation rate in the course of cooling and deformation takes the largest value at a temperature range of 120°C to 40°C (glass transition temperature), where a larger degree of deformation and a larger retention time result in a greater degree of orientation (Δn).

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The crystal structure of nylon 3 was determined from the X-ray diffraction pattern of drawn nylon 3 fibers. The crystal structure of nylon 3 is similar to that of α-type crystal of nylon 6. The unit cell was determined as follows: a=9.33A, b=4.78A, c=8.73A, β=120°. The space group is P21. The density calculated for nylon 3 crystal with four monomeric units in a unit cell is 1.39g/cm³, The nylon 3 chain are of the extended planar zigzag type. The calculated repeating unit is 4.78A. The NH--O hydrogen bond distance was calculated to be 2.88A, a perfectly reasonable value for hydrogen bond distance. The distance between sheets was calculated to be 3.78A, a resonable value for van der Waals distance. Though the crystal structures of other odd-numbered nylons, for example, nylon 7, 9, and 11 were reported to be triclinic or pseudo-hexagonal (so-called γ-type), the crystal structure of nylon 3 was determined to be monoclinc. These results suggested that concentration of amide group played an important role in crystal formation for an odd-numbered nylons.

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Polymethylallylalcohol has been prepared as a polymer which is amorphous and has; only one kind of polar group (-OH). Using this polymer, sorption isotherms of water and methylalcohol have been determined, and analysis has been made about the interaction between an amorphous polymer and a small molecular substance, which have the same kind of polar group.
In the low relative vapor pressure region of sorption isotherm, the amout of water sorbed was higher than the methanol and shows a sigmoid shape isotherm which is explained by the Langmuir type adsorption mechanism. In the high relative vapor pressure region, methanol is sorbed more than water; this fact shows that the solubilizing energy between the substances with similar structure is small.
This behavior was explained quantitatively by Flory-Huggins' interaction parameter x₁. It is evident that an amorphous polymer has also a distinct cohesive energy distribution, and the polymer is solvated by a sorptive substance from lower to higher cohesive energy regions successively.

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Poly-L-ala-gly (I), poly-gly-L-ala (II), poly-L-ser-gly (III), copoly (L-ala-gly, L-ser-gly) (3: 1) (IV), copoly (L-ala-gly, gly-L-ala) (1: 1) (V) and copoly (L-ala, gly) (1: 1) (VI) were prepared by pentachlorophenyl active ester and N-carboxy anhydride methods as crystalline part models of Bombyx mori silk fibroin.
IR absorption spectra and X-ray diffraction analysis of these synthetic polypeptides and the crystalline part of silk fibroin (VII) in a solid state gave the patterns characteristic to β-form of polypeptide. By treating polypeptide I, II, IV and VII in 9.3 M aqueous litium bromide, the conformation of these polypeptides was converted from β to α-from.
The results of ORD and CD measurements showed that conformation of polypeptides I, II, III, IV and VII in aqueous solutions was neither α-helical nor random coil structure. However, the results of IR measurements of these polypeptides in D2O indicated that they had the α-conformational structure.
These results obtained on model polypeptides I, II and IV were very similar to that of crystalline part of Bombyx mori silk fibroin.

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Cationic copolymerizations of 2-methyl-2-butene (MB-2) with isobutene (IB) and styrene (St) with titanium tetrachloride have been investigated at -78°C. Copolymerizations have been carried out in methylene chloride, n-hexane, and their equal volume mixture, and the effect of solvent polarity on the copolymerization has been investigated. True copolymers having a low molecular weight were obtained.
MB-2 can be regarded as a β-methyl derivative of IB, and MB-2 was found to be far less reactive than IB in methylene chloride. As the solvent polarity decreased, the reactivity difference between MB-2 and IB became less marked. In n-hexane the reactivity of MB-2 was found to be equal to or larger than that of IB. On going from methylene chloride to n-hexane, the nature of the propagatitng species would change from a dissociated ion form to a tight ion-pair form. In the former, the steric obstruction exerted by the β-methyl group on the transition state of the propagation reaction is serious, thus lowering the reactivity of MB-2 in methylene chloride. Another explanation for the experimental results would be that in a non-polar solvent such as n-hexane the propagating cation interacts with either α or β carbon atom of the double bond. The β-methyl group participates in the transition state to lower the potential energy, thus activating MB-2 in n-hexane.
In the copolymerization of MB-2 and St, St was found to be more reactive than MB-2 in n-hexane, But the relative reactivity of MB-2 increased with the increase of the solvent polarity. In polar solvents both r_MB-2 and r_St were larger than unity. All these phenomena have been observed in the copolymerization of IB and St. It appears to be a general characteristic in the copolymerization between an aliphatic olefin and an aromatic olefin.

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2-Methyl-2-butene and 2-methyl-1-butene have been polymerized with titanium tetrachloride in methylene chloride solution at-78°C. 2-Methyl-2-butene was polymerized in high rate without isomerization. For the polymerizatien to be initiated, however, the catalyst concentration was required to exceed the critical concentration, which was higher as the initial monomer concentration became higher. Hence it was suggested that a part of catalyst initially present was inactivated by an interaction with 2-methyl-2-butene. Only methanol-soluble products were obtained, which contained a mixture of dimers (bp ca. 93 °C) and a non-volatile viscous liquid having the number average molecular weight 5. The low molecular weight in spite of the high polymerization rate was explained in terms of a preponderence of monomer transfer reaction. The structure of the polymer-end studied by IR and NMR spectroscopies indicated that two sorts of monomer transfer reaction exist, i. e., a proton loss from a propagating carbonium ion and a hydride ion abstraction from a monomer molecule.
2-Methyl-1-butene was polymerized more quickly than 2-methyl-2-butene, but an isomerization to 2-methyl-2-butene was always accompanied. The formation of 2-methyl-2-butene gave complex aspects to the polymerization of 2-methyl-1-butene. Methanol-insoluble polymers were obtained together with methanol-soluble oligomers. The intrinsic viscosities of the former product were, however, as low as 0.03dl/g (toluene, 30°C). A monomer transfer reaction with 2-methyl-2-butene, which is the isomerization product of 2-methyl-1-butene, may be a reason for the low molecular weight.

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Cyclohexene-4, 5-dicarboxyaldehyde (I) and 1-methylcyclohexene-4, 5-diccarboxyaldehyde (III) were polymerized with cationic, anionic and coordination catalysts. These monomers readily yielded cyclopolymers soluble in common organic solvents (benzene, THF, CCl₄ etc.), with all the catalysts used. The extent of cyclization was higher than 98%. The cyclopolymers were obtained from I at 30°C, suggesting unusually high ceiling temperatures for these dialdehydes. The enhanced reactivity of these monomers relative to cyclohexene-4-carboxyaldehyde and the high tendency of cyclization were considered to be caused by fixation of the adjacent aldehyde groups in the cis positions. The cyclopolymers showed relatively high softening temperatures (120-146°C for I and 123-150°C for III) and gave flexible films.

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The polymerization of butadiene initiated by reduced nickel-organic halide systems was investigated. It was found that the kind of the halide components in the initiator systems and of the solvents used significantly affected the microstructure of the resulting Polybutadienes. In benzene, the initiator systems consisting of the reduced nickel and organic chlorides or bromides, such as CCl₄, CHCl₃, CBr₄, CHBr₃, etc., gave polybutadienes which were predominantly composed of cis-1, 4 microstructure. On the other hand, in tetrahy. drofuran, the initiator systems containing bromides or iodides, such as, CBr₄, CHBr₃, CHI₃, CH₂I₂, etc., gave the polymers which were mainly composed of trans-1, 4 microstructure. A coordinated π-allyl mechanism for the polymerization with these initiator systems is presented and discussed.

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The AIBN-initiated radical polymerization of styrene in the presence of aromatic nitroso compounds in benzene was studied at 50, 60 and 70°C. Nitrosobenzene behaved as an effective inhibitor. But it was found that the reaction of nitrosobenzene with styrene also took place and a part of nitrosobenzene disappeared during the inhibition time. This fact was confirmed by the result that the rate of disappearance of nitrosobenzene calculated from the inhibition time was slightly larger than that from the direct reaction between nitrosobenzene and AIBN.
The reaction of aromatic nitroso compounds with styrene was carried out. As the results, the rate of the reaction was greatly effected by the substituents in nitroso compounds.
Inhibition time of polymerization was also influenced by the substituents in the same manner mentioned above.

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The glass transition temperatures of copolymers of maleic anhydride (MAn) with methyl acrylate (MA), methyl methacrylate (MMA), styrene (St) and vinyl acetate (VAc) were measured by using a volume dilatometer. The glass transition temperatures increase markedly with an increase in maleic anhydride content. The dependence of glass transition temperatures of MAn-MA and MAn-MMA upon the composition is interpreted by the Gibbs-DiMarzio-Uematsu theory. The glass transition temperatures of copolymers with alternating structure are in the order, MAn-St, MAn-MMA MAn-MA>MAn-VAc. This result is discussed in terms of chain stiffness.
Volume expansions of MAn-MA and MAn-MMA in glassy and rubbery states have a tendency to decrease with an increase in maleic anhydride content. However, the product T_g·Δα, where Δα is the difference in volume expansion above and below glass transition temperature, is nearly constant, regardless of composition.

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Methyl methacrylate, methacrylic acid (MAA), methyl acrylate and acrylic acid (AA) were polymerized in the presence of polyvinyl pyrrolidone (PVP) of 36wt% using azobisisobutyronitrile. MAA and AA were also polymerized in dilute aqueous solutions of PVP using potassium persulfate Stereo-regularities of the polymers thus obtained were examined. Poly-MAA obtained by polymerization in the presence of PVP of 36wt% was isotactic, while stereo-regularities of the other polymers were nearly the same as those of the corresponding polymers obtained by radical polymerization in the absence of PVP.

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