In order to plasticize the vinyl chloride grafted ethylene-vinyl acetate copolymer (EVA-C) effectively, the melt rheological behavior in steady flow and the mechanical properties of the sheet of polymer blends of EVA-Cand ethylene-vinyl acetate copolymer (EVA) were determined and the structure of the blends was discussed.
It seemed that the structure of the blends was microscopically heterogeneous, but a partial compatibility wasconceivable in some cases.
The changes in the melt viscosity and the tensile modurus with the content of EVA suggest that EVA is usefulfor a high molecular plasticizer for EVA-C, and EVA having similar vinyl acetate content to EVA-C and highermelt index is more effective as the plasticizer for EVA-C.

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The possible application of phase-separation process has been suggested for the manufacture of porous sheet of polystyrene. The effects of type and added amount of theta-solvent (naphthalin, biphenyl, and anthracene) onthe melt rheological properties observed by the Weissenberg rheogoniometer and on the phase-separation temperatureestimated from cooling curve were determined.
(1) The melt viscosity, its activation energy, and the shear modulus decreased with the increase in thetheta-solvent content, as reported in previous literatures on polyethylene and polypropylene.
(2) The changes in the shear dependence of the viscosity with the theta solvent addition suggested the increasedsize and more heterogeneous distribution of the flow units.
(3) At lower content of theta-solvent the phase-separation became unclear, and at higher content the meltstrength was lost.
(4) Little difference in rheological behavior was observed among the types of theta-solvents, but anthraceneexhibited higher phase-separation temperature.
(5) The sheet formation by this process may be difficult for polystyrene alone, but the melt coating on another substrate appears hopeful for producing a porous layer after the extraction of the separated theta-solvent.

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Melt flow properties of ethylene-vinyl chloride copolymer (E-PVC), a modified PVC, were investigated by capillary viscometers at 190°C. Samples were prepared by mill-mixing with Sn-system recipe at various mixingtemperatures.
As the mixing temperature increased, the apparent melt viscosity, the entrance pressure loss and the endcorrection term decreased. Every end correction term became minimum at the shear rate of ca. 100 sec. ^-1 Thefracture surface of E-PVC extrudate always showed hetrogeneous appearance. These results may be explained thatwith increasing temperature of mixing the aggregate of E-PVC decreases and the flow becomes homogeneous, i.e., segment flow.

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Glass fiber reinforced polycarbonate containing discontinuous short glass fibers was subjected to plane bending fatigue by a constant load type fatigue tester to study the fatigue crack propagation and the role of glass fibersin the fatigue phenomenon.The fatigue strength increased with the increase of glass fiber content. Many microcracksformed in the boundary of the matrix and fiber ends joined together to form macroscopic maincracks whichpropagated through the specimen. Crack growth rate of the specimens decreased with the increase of glass fibercontent. Fractographic observation revealed that the crack propagation was suppressed by the glass fibers

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In the case of repeated plane bending of glass fiber reinforced Nylon 6 characteristic patterns due to the fiber orientation were observed by optical microscope on the crack surfaces. The diagrams of stress amplitude and thenumber of cycles needed for the fracture revealed the anisotropy of the fatigue property which depends on thefiber content. Yokobori's theory on the fatigue of metal and containing non-metal was applied to explain theresults of the experiment.

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Changes of dynamic modulus and loss tangent of the composite sheet of low density polyethylene steel under repeated plane bending were measured by means of forced exciting bending vibration resonance method at low frequency.There are three stages of the dynamic modulus changes; the first the modulus decreases with increasingnumber of repeating cycles, the second it is almost constant, and in the last stage the modulus changes markedlyand shows rapid decreases at the instant close to the fracture.
The changes of loss tangent had a contrary tendency to the modulus changes. The starting point of each state, the period of duration and the degree of changes are closely related to the amplitude in the fatigue test. Thisresult is similar to that obtained for FRP or FRTP. The fracture surfaces in T-type peel test were observed by E.M.X for unfatigued and fatigued specimens with the conclusion that the modulus changes occurred in thevicinity of the boundary layer

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Aliphatic polyesters such as polycaprolactone, polyethylene adipate, and polydecamethylene sebacate crystal-lized epitaxially on uniaxially oriented high density polyethylene. The similarity of crystal structures between aliphatic polyesters and polyethylene will be favorable to the deposition of polyester molecules on the minimumpotential sites of polyethylene crystal in their interfacial region. Polycaprolactone crystallized in spheruliticmorphology on the surfaces of low density polyethylene and irradiated high density polyethylene with distoredcrystal regularities. Close correlation of degree of lattice distortion with the morphology of overgrown crystalsproved that lattice distortion plays a dominant role in the surface nucleation process.

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Epitaxial crystallization of some aliphatic polyesters and polycaprolactam on uniaxially oriented polyethylene, polypropylene, polyoxymethylene, and polycaprolactam were studied. Only caprolactone among the aliphaticpolyesters crystallized epitaxially on drawn polycaprolactam. Aliphatic polyester epitaxy on aliphatic polyamide isthought to be affected by the interaction of the ester groups with the amide groups. Polycaprolactam epitaxy onhigh density polyethylene was observed, though polyethylene crystallized randomly on drawn polycaprolactam.Polycaprolactone crystallized in the form of spherulites on drawn polypropylene. This result is probably due tothe remarkable lattice misfit in three directions and lower crystallinity of the substrate.

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Mechanism of the curing reaction for bisphenol-type epoxide resin and its derivatives having methyl side group in the main chain in the presence of various harciners, such as aliphatic and aromatic amines, polyamide, and acid anhydride has been studied by the measurements of dynamic mechanical properties of the cured resin.
Tensile shear strength of cured epoxide resin in cohesive fracture region is a function of M_e. or modulus. Inthe case of a peeling test, the mechanism of fracture changes from cohesive to contact fracture according to theircrosslinking density, and the maximum value of peel strength is observed at the transition point. Glass transitiontemperature of the system coincide with the test temperature at this point.

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Tetraoxane, tetramer of formaldehyde, was polymerized in solid state in n-heptane using BF₃O (C₂H₅) ₂ as catalyst. The polymerization proceeded without a change in a shape of crystal particles of tetraoxane. The rateof polymerization was proportional to the catalyst concentration, and it was independent of the monomer concentration.The rate of polymerization and the molecular weight of polymer increased with increasing polymerizationtemperature. These features are quite similar to those observed for trioxane. Since the molecular weight ofthe polymer increased with increasing conversion and the molecular weight of the polymer decreased by the additionof a small amount of benzene and ethylene chloride, the good solvent for tetraoxane, a high molecular weightpolymer does not seem to be formed on a surface of the monomer crystals. The above results suggest that thepolymerization proceeds in solid state.

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Tetraoxane was polymerized in solid state by BF₃, gas without suspension medium. The kinetic feature was similar to that of the suspension polymerization of tetraoxane. The molecular weight distribution of polymerswas very broad, and the molecular weight of polymer determined at the initial stage of polymerization was lowand increased with increasing conversion. In the disorientated crystal which was prepared by cooling moltenmonomer, the molecular weight of polymer increased very slowly with increasing conversion. This result suggeststhe orientation of monomer in the crystal is favorable for the propagation reaction.

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The solid state polymerization of tetraoxane and trioxane catalyzed by BF₃, or BF₃O (C₂H₅) ₂ was discussed on the basis of an X-ray study. Polyoxymethylene produced from trioxane was highly oriented and showed highmelting point (188-190°C). On the other hand, degree of orientation and melting point (181-185°C) of polymersprepared from tetraoxane were not so high as those produced from trioxane. In the solid state polymerization oftrioxane, a highly oriented polymer was obtained at low conversion and at high temperature. In the polymerizationof tetraoxane, the orientation of polymer slightly decreased with increasing temperature and increasedwith increasing conversion. The degree of orientation and the amount of twin structure of polyoxymethylenewere explained in terms of the crystal structure of tetraoxane and trioxane.

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Lactamimines which contain an amide and an imino groups within the same ring have been synthesized. Polymerization and copolymerization of lactamimines with other cyclic compounds were carried out in order to elucidate the ring-opening polymerizability of cyclic compounds having bifunctional groups. 6-Membered lactamimine (2-ketopiperazine) did not give any polymer, while 7-membered (5-homopiperazinone) polymerized with H₃PO₄ and gave a greasy poly-amide-imine. 2, 2, 7, 7-Tetramethyl-5-homopiperazinone (TMI) containing four methyl groups in the lactam ring was synthesized from triacetoneamine.
The polymerization of TMI did not take place with us ual catalysts, while TMI polymerized and copolymerized with ε-caprolactam or ω-laurolactam in the presence of Lewis acid catalysts such as SnCl₄ or AlEtCl₂. Resulting polymers and copolymers were grease-like solids.

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When a chloroform solution of S₂Cl₂ was brought into contact with acetone, vigorous reaction was observed to give a new type of polymer, which showed mp. 56-57°C, sulfur content 60.75%, 1710cm^-1, 1360cm^-1, 500cm^-1, 480cm^-1 in infrared spectrum, 1.62ppm (CH₃, group) 2.60, 2.73ppm (CH₂, group) in NMR spectrum, in CDCl₃ solution. Its structure was suggested as-(Sx-C (CH ₃) ₂-O-)-(Sx-CH₂-CO-CH₂)-(Sx'-CH₂-CO-CH₂). Molecular weight of this polymer determined by vapour pressure osmometer in chloroform solution was 2360.

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