Surface grafting of polyethylene by mutual irradiation in methyl acrylate vapor. I. γ irradiation

Mutual irradiation of polyethylene (PE) in methyl acrylate vapor easily forms a poly(methyl acrylate) (PMA) homopolymer layer on the inner graft copolymer layer consisting of both PE and PMA components as a result of the rapidly increasing surface-graft composition. This growth process of surface grafting has been found to provide some specific kinetic features different from those in other surface-grafting systems. With formation of the surface homopolymer layer, low- and highdensity PE sheets give the same grafting rate, whereas both sheets give different rates in grafting stages or conditions in which the homopolymer layer is not formed. This result indicates that most monomers, penetrating across the surface, are entrapped or consumed in the surface homopolymer layer; accordingly the rate becomes independent of the type of PE sheets that have significantly different diffusion coefficients. The thickness of the inner graft copolymer layer, which is kept constant after homopolymer-layer formation, increases with decreasing dose rate and with increasing monomer vapor pressure and temperature. This behavior can be qualitatively explained according to an equation for the initial steady-state grafting depth.     

Vacuum lithography—A completely dry lithography using plasma processing

The purpose of this paper is to describe a thoroughly dry lithography using plasma polymerization and plasma etching. The new lithography is named vacuum lithography because all processes are performed at reduced pressures. Resist films were formed in bell-jar-type and argon-flow-type reactors. The controllability of plasma polymerization is discussed with respect to the type of reactor and gas mixture. A pattern was delineated in the resist using an electron beam, and it was developed by plasma etching with a mixture of argon and oxygen. It was found that the quality of the plasma-polymerized resist depends strongly on the polymer structure and on the plasma etching conditions. In this experiment, the recorded values of sensitivity and value of plasma-polymerized methyl methacrylate were 700 µC/cm² and 1, respectively.     

Thin Polymer Films by the Glow-Discharge Indirect Method

The growing mechanism and the structure of thin polystyrene film by the glow discharge-indirect method are discussed. A theoretical relationship between the growth rate of polymerized film and the discharge condition is deduced on the basis of Poll's model, taking the charge transport processes in the discharge space into consideration: 1) the ambipolar diffusion, 2) the recombination of charges forming the ion sheath, and 3) the effect of stray capacity. Substitution of possible values of physical parameters on the gaseous plasma into the theoretical relation give a reasonable growth rate which agrees well with the experimental results. From NMR, ESR, and dielectric experiments, it is suggested from the molecular and morphological structure of the film that small molecules and free radicals remain, but most of the film consists of a three-dimensional mesh structure.     

Straightforward approach to the discrimination of (4R)- and (4S)-beta-isocryptoxanthin from a conformationally insensitive CD band

A straightforward strategy is reported for chiral discrimination in a specified carotenoid using a CD band, which is insensitive to conformational changes, computed by quantum chemical calculation.     

Thermal decomposition behavior of mono-aminimides and their application to polymerization of epoxide

Mono-aminimide compounds [N,N-dimethyl-N-(2-hydroxypropyl)-amine-N′-propionimide ( 1 ), trimethylamine valerimide ( 2 ), and trimethylamine benzimide ( 3 )] were found to exhibit different thermal decomposition behaviors and polymerization efficiencies for an epoxide (phenyl glycidyl ether, PGE). The thermal decomposition rate of aminimides at 150°C decreased in the order 1 > 2 > 3 . It seemed that hydrogen bonding enchanced the decomposition rate, and the resonance effect induced by the phenyl group suppressed the decomposition. 1 was thermolyzed to give isocyanate and tertiary aminoalcohol, which subsequently reacted with each other to give isocyanate and tertiary aminoalcohol, which subsequently reacted with each other to give urethane. When 2 was heatted, the isocyanurate generated from 2 remained intact. On heating of 3 , we observed the formation of triphenyl isocyanurate. PGE reacted with those aminimides and gave different products depending on their thermolyzed products. Equimolar mixtures of isocyanate, tertiary amine, PGE were used in the model reactions, and the thermal reaction between the expected decompostion products of aminimides was investigated in the presence and absence of PGE. The rate of PGE consumption was in the order PGE + 2 > PGE + 1 > PGE + 3 . It is clear that the formation of urethanes and oxazolidone derivatives affects the polymerization process.     

Stochastic levi sums

An analogy of Levi sums is considered for a class of stochastic partial differential equations to construct their stochastic fundamental solutions. These notions are shown to coincide with Donsker's delta functions, typical generalized Wiener functionals, which have been studied in the frame of the Malliavin calculus. © 1994 John Wiley & Sons, Inc.