We have used tensile testing to investigate the behavior of crack opening for low density polyethylene film having a single edge notched crack. The following conclusion were obtained. 1) Crack opening and fracture phenomena were explained by enlarging of plastic deformation in the full ligament that the stress concentration took place at the crack tip. 2) The stress concentration at the crack tip increased with displacement along with the increment of the initial crack length. 3) We found a different tendency to decrease with displacement between the thickness of the crack tip and the width of ligament.

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An epoxy monomer, 1-N- (2, 3-epoxypropyl) carbazole was synthesized and anionically polymerized with the Et₂Zn-MeOH complex, KOH, t-BuOK, and Et₃Al. The polymer, obtained with the Et₂Zn-MeOH complex as catalyst, was insoluble in common organic solvents because it had highly stereoregular main chains. However, the polymers, polymerized with KOH and Et₃Al, had main chains of random configuration and low molecular weights, but gave cast films. The racemic monomers was optically resolved by use of a high performance liquid chromatograph packed with a chiral compound and polymerizerd with KOH. ¹³CNMR measurement showed the polymer obtained was found to have high isotacticity. The X-ray diffraction pattern of the isotactic-rich polymer was different from that of the atactic one, revealing that there is difference in their crystalline structure between them.

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Plasma polymerization of hexafluoroethane (C₂F₆) has been examined. Fluorine-containing thin films were obtained from C₂F₆ without addition of any hydrogen or hydrocarbons. IR and XPS analysis indicated that the main feature of the plasma polymers was a linear -CF₂CF₂- structure. They contained considerable amounts of branched groups. It was thought that the plasma polymers included low molecular weight components because significant quantities of the polymers were soluble in organic solvents. Molecular weights of plasma polymers were measured by GPC. With increasing RF power, fluorine content of the plasma polymers increased, and both the ratio of branched structures and the molecular weight decreased. The increase in amounts of atomic fluorine detached from C₂F₆ resulted in decomposition and fluorination of the plasma polymer.

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A characterization method of a polymer-polymer coated surface has been developed using Fourier transform infrared microscopy. A cross section of a coated sample was prepared as a microtomed cross section perpendicular to the film structure's thickness. The coated sample was made by coating a polyurethane layer on the ethylene-acrylic acid copolymer/ethylene-ethyl acrylate copolymer. The mixed phase of polymer-polymer was detected in the coated surface; this phase was approximately 140μm in thickness. An interaction (about 100 gm in depth) was detected between a secondary amine in the polyurethane and a carboxyl group in the ethylene-acrylic acid copolymer/ethylene-ethyl acrylate copolymer.

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Internal stresses of UV-cured epoxide resin coatings were determined by measuring the deflection of the coated substrate with a laser displacement detector. In this method, we could measure precisely the internal stresses generated in both the curing and cooling processes of the coatings. The internal stresses of coatings decreased for smaller increments of coating temperature during UV-irradiation. This phenomenon is due to the decrease in the shrinkage of coatings during the cooling process. The internal stresses also decreased as the coating thickness was increased. This behavior of the internal stress was based on lack of uniformity of the degree of curing and the coating temperature in the curing and cooling processes. In the curing process, the curing shrikage of the surface layer is relaxed by the ductile deformations of the inner layer which is not still cured completely, while in the cooling process, the cooling shrinkage of the inner layer is suppressed by the surface layer which was cooled earlier and thus has a higher modulus.

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Radical copolymerizations of acrylonitrile (AN), N-phenylmaleimide (PMI), and N-p-chlorophenylmaleimide (CPMI) with a-methylstyrene (MS) were conducted in cyclohexanone at 60°C with AIBN. In the copolymerizations of PMI and CPMI with MS, the resulting copolymers were found to have highly alternating structures irrespective of the ratio of comonomers in feed. On the other hand, copolymerization of AN with MS gave random copolymers. The copolymerization parameters (r₁ and r₂) of each copolymerization system were determined. Weak monomer complexation between MS and PMI or CPMI was observed in ¹H NMR measurements in CDCl₃ at 30°C. The glass transition (T_g) and initial thermal decomposition (T_d) of these copolymers examined by DSC and TGA showed that MS-PMI and MS-CPMI copolymers were characterized by high T_g and thermal stability.

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The cross-linking by adding cross-linking agents to polyamideamide (PAI) resins was studied. The following results were obtained. (1) PAI can be cross-linked at lower temperatures than 200°C by some polyfunctional agents which react with end groups of PAI. (2) Polyfunctional epoxy compounds (especially ones derived from phenol-nevola. c resins) are the most effective cross-linking agents for PAI. (3) Melting temperatures of PAI can be enhanced more than 100°C by cross-linking with epoxy compounds. (4) But PAI cross-linked by epoxy compounds have a lower softening temperature (or glass transition temperature), lower thermal decomposition resistance, and a higher coefficient of thermal expansion compared with the original PAI. These effects are due to mixing of large amounts of epoxy compounds which are less heat resistant than PAI is. To effect cross-linking successfully, it is preferable to use cross-linking agents in as small amounts as possible.

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Molecular weight changes during poly (p-oxybenzoyl) whisker formation from p-acetoxybenzoic acid in liquid paraffin were studied. Our electron microscope observation suggestd that the needle crystals in the very early stage of polymerization consist of stacks of oligomer lamellae. Here, the degree of polymerization of precipitated oligomers was found to be about 8, from analysis of oligomers dissolved in liquid paraffin by HPLC method. Furthermore, transesterification in the interlamellar regions starts as soon as crystals precipitate. The average DP of whiskers obtained with 3 min after crystal precipitation increases from 8 to 48. These crystals show fibrillation by crushing of whiskers in liquid nitrogen or etching in KOH solution. This fact indicates that reorganization into extended chain crystals occurs accompanied by the increase of DP. On the other hand, DP of the eventual whiskers increased by 1860. That is, the average molecular length exceeds 1μm. The formation of such high molecular weight polymers in the solid state polymerization is caused by the closely packed structure of the end groups.

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The falling behavior of molten poly (ethylene terephthalate) has been simulated by solving several differential equations. The basic equation in the simulation model was derived from energy balance. The simulated results of liquid thread diameter were compared with experimental data. This simulation represented the changes with clasped time of the liquid thread diameter, velocity, and temperature. We discuss the liquid thread length, i. e., the break up length, as a function of the diameter of nozzle, the velocity and the polymer viscosity at the exit of the extruder.

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Selective polymerization of glycidyl vinyl ether (GVE), which has two polymerizable functional groups, such as epoxy and vinyl ether groups, was investigated. Radical coplymerization of GVE with various vinyl monomers was carried out using AIBN as an initiator under nitrogen. When N-phenylmaleimide or N-phenoxycarbonyloxymaleimide were used as comonomers, copolymers having pendant epoxide were obtained in high yield. Alternating ring-opening coplymerization of GVE with phthalic anhydride was performed using various catalysts such as tert-amines, quaternary ammonium salts or crown ether complexes. The polymerization gave a polyester having pendant vinyl ether groups. In this reaction the dicyclohexano-18-crown-6/potassium phenoxide complex showed the highest catalytic activity. Cationic polymerization of GVE was also performed; however, no soluble polymer having pendant epoxide was obtained with BF₃OEt₂ and CF₃SO₃H. On the other hand, cationic polymerization of GVE did not take place with I₂ and HI/I₂.

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In order to investigate the elastic property of BLDPE-tetralin gel, the static shear modulus G of the gel was measured at 25°C as a function of polymer concentration. The size of crystalline junction ζ (i. e., ethylene-unit length in a crystallite) was estimated from gel-melting temperatures using Takahashi's theory. BLDPEs having different numbers of long-chain branches (LCB) and different molecular weights (MW) were used. As a result, both G and ζ became large with increasing MW, but became small with increasing number of LCB. Further, G increased with increasing ζ. The concentration dependence of G was analyzed by the following power law equation: G ∝ (C-C₀) ^t, where C₀ is the critical gelation concentration. In the region near C₀, the elasticity exponent t was found to be ca. 2 without regard to the difference in LCB and MW of samples. The value observed is in agreement with the critical exponent expected from the percolation theory in dimensionality d=3.

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The flow curves of miscible blends of poly (phenylene oxide) (PPO) and polystyrene (PS) were measured at shear rates up to 10⁷s^-1. The component polymers have quite different glass transition temperatures; the blend has one glass transition temperature between those of the component polymers. A second Newtonian region was observed for PS in a high shear rate region (>10⁶s^-1) following the first non-Newtonian region. An increase in the viscosity was found at a shear rate of about 3.5×10⁶s^-1, above which the second non-Newtonian region appeared. The viscosity of PPO 50%-PS50% blend was higher than that of PS at shear rates up to 10⁷s^-1 and the non-Newtonian region was observed in the flow curve of the blend. The flow curve of PP030%-PS70% blend was near to that of PS at the low shear rate region and was near to that of PPO50%-PS50% blend at the high shear rate region. A pseudo-Newtonian region was observed in between. The second Newtonian region was observed for PPO10%-PS90% blend. The beginning point of the pseudo-Newtonian or Newtonian region shifted to the higher shear rate with increase of PS content. The flow behavior of miscible blends of PPO and PS was very similar to that of immiscible polymer blends. The flow behavior of miscible blends is considered to depend on the mixing level of macromolecules of each component and to be similar to that of immiscible polymer blends when some amount of macromolecules of each component can behave independently of each other. Nuclear spin-spin relaxation time measurements on the blends exposed to the high shear proved this consideration.

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When a prebaked positive photoresist is dipped into developer, the dissolution rate of the photoresist at the beginning is extremely slow; but as the time elapsed, it becomes faster. This phenomenon is called “induction effect”, it varies as a property of the prebaked photoresist surface layer. We analysed the matter dissolved in the developer into which the photoresist has been dipped and discovered that the 2, 3, 4-trihydroxybenzophenone (TBP) contained in photo-active compound has been reduced. TBP has a the good solubility in aqueous alkaline solution, and it is presumed that low dissolution rate of photoresist surface layer in the developer is caused by evaporation of TBP from the photoresist surface during prebaking.

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