Asymmetric polymerization of N-phenylmaleimide

Summary Asymmetric polymerization of N-phenylmaleimide was carried out with the complexes of butyllithium and chiral ligands and optically active polymers were obtained. The optical activity of the polymers should be based on the chiral trans structure of the main chain.A part of this work was reported at The 28th Meeting of Polymer Science (Kobe), July 1982     

Stereospecific anionic polymerization and copolymerization of 1,1-diphenylethyl methacrylate

1,1-Diphenylethyl methacrylate (DPEMA), which is a new methacrylic ester, was synthesized and polymerized by n-butyllithium (n-BuLi) in toluene and THF. The triad tacticity of the polymers was determined from the n.m.r. spectrum of poly(methyl methacrylate) (PMMA) which was derived from them. A highly stereoregular polymer was not formed either in toluene or in THF by n-BuLi between ?78° and 30°C. In toluene, the tacticity depended very much on the polymerization temperature, and unexpectedly, the polymer obtained at ?78°C was rich in syndiotacticity. The polymers obtained in THF were atactic regardless of the temperature. A highly isotactic polymer was formed with Grignard reagents. DPEMA (M₁) was also copolymerized with methyl methacrylate (MMA), diphenylmethyl methacrylate (DPMMA), and trityl methacrylate (TrMA) (M₂) in toluene and THF with n-BuLi; the tacticity of the copolymers was determined. Generally, the stereoregularity of the copolymers was lower than those of the M₂ homopolymers. In the copolymerization with MMA monomer reactivity ratios were also determined.     

Graft copolymerization onto protein by the ceric ion method. Studies on grafting site

Graft copolymerization of methyl methacrylate and acrylamide onto ovalbumin was carried out with redox system with ceric ion. Initiation of grafting occurred very rapidly, and the number of grafting sites reached a maximum after about 2 min. regardless of initial ceric ion concentration. The grafted polymer chains were separated by selective hydrolysis of the protein backbone with hydrochloric acid or protease in order to characterize the graft copolymers. The grafted polyacrylamide separated by the proteolytic digestion contained a carbohydrate residue at the end of the polymer molecule. The problem of grafting sites on ovalbumin is discussed.     

Chemical composition of the wax secreted by a scale insect (Ceroplastes pseudoceriferus Green)

The wax material in the secretion of a scale insect,Ceroplastes pseudoceriferus Green was analyzed chemically with special interest to the composition of higher fatty acids and higher alcohols. The wax consists of 34.2% fatty acids, 27.1% unsaponifiable matter and 29.5% resin acids. The fatty acids were found to be a complex mixture of 15 normal acids ranging from C₈ to C₃₂. Of these, octacosanoic, triacontanoic and dotriacontanoic acids comprise over 30% of the wax. Presence of relatively large amount of unsaturated fatty acids of the C₁₈ series (2.8% of the wax) is of particular interest. From the unsaponifiable fraction, only one saturated straight chain aleohol, bexacosanol, was detected (2.7% of the original wax). The other unsaponifiable matter was considered to be cyclic or branched carbon chain, and consisted of at least 12 to 20 compounds. The resin acid fraction was also found to be a complex mixture of at least 13 to 14 components.     

Long-term experiences of 3.5 mgd Roga-spiral RO installation

The 800,000 GPD Reverse Osmosis Plant was put on stream in late 1971 at the Kashima Steel Works of Sumitomo Metal Industries Ltd., Japan and it has been expanded up to the capacity of 3.5 MGD, the world's largest RO Plant now under commercial operation.

Development of the most appropriate pretreatment process and application of specially determined indexes to evaluate the pretreated RO feed water-quality have greatly contributed to maintain the membrane performance at satisfactory level and to prolong or lengthen the membrane life-time. During these four and half years since its installation, operation results show the plant availability of 98%, the module replacement of 5–6% per year and the flux decline slope of -0.02 with better salt rejection than the guaranteed level.

Kurita Water Industries Ltd. has installed many RO plants since 1971, aggregating to approx. 12 MGD in total capacity. Informations are also reported herein regarding other two bigger installations, 1.4 MGD and 2.5 MGD in capacity respectively.     

Secondary electron emission from polymers and its application to the flexible channel electron multiplier

The basic characteristics of secondary electron emission (SEE) from various organic compounds have been investigated, and a channel electron multiplier with high gain and flexibility has been developed. The maximum SEE yield is higher for the aliphatic compound than for the aromatic, and is higher for the organic solid with high ionization potential. By studying the SEE yields from the electron-conductive polymeric compositions which consist of plasticized poly(vinyl chloride) and electroconductive particles (NaTCNQ or carbon black), it is shown that the SEE yield depends mainly on the characteristics of the matrix polymer and is almost independent of the addition of electroconductive particles which inherently have low SEE yields. Adding less than 5% stabilizers to these polymeric compositions has little effect on the SEE yields. A flexible channel electron multiplier (FCEM) made of the electron-conductive polymeric composition shows the following characteristics: gain ? 10⁸ (applied voltage of 3 kV); rise time ? a few nanoseconds; background count rate < 0.1 cps; and maximum output current ? 10^?6 A. As a photon detector in the vacuum UV region, the FCEM shows a threshold value of 8.4 eV for photoelectric emission.     

Research on structural integrity of pressure boundary in light water reactor designs

This paper is a review of the recent researches performed and planned in Japan relevant to the structural integrity of the pressure boundary in light water reactor designs. Various aspects of relevant work on materials, pressure vessel and piping models are described.     

Superconducting to normal transition of type-II Ta by a rectangular current pulse

The superconducting to normal transition by a rectangular pulse current in type-II Ta has been investigated. The potential drop along the specimen is observed as a function of time. The voltage pattern and the magnitude of the potential drop are obtained as functions of current amplitude, temperature, externally applied magnetic field, the angle between magnetic field and specimen axis, and values. The transition mechanisms are discussed. It is also shown in this experiment that the flux flow or flux creep and flux jump occur. A support to the paramagnetic current flow in the presence of longitudinal magnetic field is given.