Photodegradation of polyethylene in the presence of ferric salt: Influence of ferric acetylacetonate on model compounds

The influence of ferric acetylacetonate [Fe(acac)₃] on the photodegradation of model compounds of polyethylene (PE) was examined. By studying electron-spin-resonance (ESR) spectra of photoirradiated compounds such as 1-octene and 1,7-octadiene, which contain carbon double bonds, Fe(acac)₃ was found to accelerate the formation of allyl radical by contact with them. On the other hand, Fe(acac)₃ suppressed the radical formation based on Norrish type I reaction in a carbonyl group of compounds such as 2-octanone and 3-octanone. Based on the study of ultraviolet (UV) spectra as well as ESR spectra on photoirradiated samples, the influence of Fe(acac)₃ on the photodecomposition of model compounds of PE was discussed. Finally, the discussion turned to the mechanism of photodecomposition of PE in the presence of ferric salt.     

Über die Phosphidierung des Nickels durch Phosphortrichlorid

On the Phosphidation of Nickel by Phosphorus Trichloride The phosphidation of nickel sheets by phosphorus trichloride vapor of 30 and 50 Torr has been studied kinetically by gravimetric means in the temperature range of 400–650°C in hydrogen atmosphere. The phosphidation proceeded generally according to the parabolic rate law. The parabolic rate constant increased with an increase of temperature, and its temperature dependence yielded the activation energies of about 33 and 47 kcal/mole for 400–550 and 550–650°C, respectively. X-ray and electron microprobe analyses showed that surfaces of the specimens phosphidized are made up of mixtures of Ni₂P and Ni₆P₅, and that at the phosphide/metal interface the compound Ni₂P is formed. The experiments using argon as carrier gas resulted in the formation of both the phosphides and the chlorides, and this fact could be explained in terms of thermodynamics.     

Effects of solvent in photo-induced graft copolymerization of vinyl monomers on cellulose

The effects of swelling of the sample and polymerization solvents were studied for photo-induced graft copolymerization of vinyl monomers on cellulose. The graft copolymerization of methyl methacrylate (MMA) was activated by swelling of the sample or organic solvent-water solutions within a certain range of their concentrations. Though each organic solvent gave a maximum in per cent grafting and the number of grafts at about 25 vol-% concentration, the initiation reaction scarcely took place at 100% concentration; thus, the solvent itself is considered to have a negative effect. The solvents used in the experiments were all hydrophilic, such as methanol, acetone, and dioxane. The average molecular weight of the grafted PMMA differed in each solvent, indicating a different characteristic effect of solvent on the growing grafted polymer radicals. The presence of ferric ion as a sensitizer stimulated further the contributions of the sample swelling and the organic solvents to the copolymerization reaction. A similar effect was observed for styrene as for MMA, but not for acrylic acid and methacrylic acid.     

The nature of europium ion in carbonate solution and polarographic determination of micro amounts of europium

The nature of the complex europium carbonate ion in concentrated carbonate solution was studied polarographically. A polarographic method for the determination of micro amounts of europium ion in the presence of diverse ions (and especially lanthanides) was developed.     

Synthesis of polyphthalimidines with benzylidene group from aminophthalide monomers

Two aminophthalide monomers, 6-amino-3-benzylidenephthalide (I) and 3-(p-aminobenzylidene)phthalide (II), underwent self-polycondensation in o-phenylphenol at 250°C to yield polyphthalimidines with inherent viscosities up to 0.5 dL/g. These polymers were readily soluble in a variety of solvents such as dimethylformamide, dimethyl sulfoxide, m-cresol, pyridine, and methylene chloride. The temperatures at which a 10% weight loss occurred by thermogravimetry in nitrogen were 460°C for the polymer derived from I and 490°C for the polymer from II. The glass transition temperature of the polymer from I was 332°C, determined by thermomechanical analysis.     

Fused silica capillary tube isotachophoresis using a multichannel photodiode array detector

Isotachophoresis carried out in a 0.25 mm i.d. fused-silica capillary tube yielded high resolution, compared with that in a fluorinated ethylene-propylene polymer tube. The use of an ultraviolet-visible multichannel spectrophotometer with photodiode array as detector together with a cross flow cell (volume 0.01 μl) was investigated. The system was successfully applied to the analysis of cationic dyes such as neutral red, bismarck brown, and basic fuchsine.     

Synthesis of poly(benzoxazole)s by direct polycondensation of dicarboxylic acids with 3,3′-dihydroxybenzidine dihydrochloride using phosphorus pentoxide/methanesulfonic acid as condensing agent and solvent

A convenient method for the synthesis of poly(benzoxazole)s of high molecular weights has been developed. These polymers were prepared readily by direct polycondensation of aromatic dicarboxylic acids containing phenyl either structure with 3,3′-dihydroxybenzidine dihydrochloride using phosphorus pentoxide/methanesulfonic acid (PPMA) as condensing agent and solvent. Polycondensations proceeded fast and was completed within 5 h at 140°C and produced poly(benzoxazole)s with inherent viscosities up to 4.6 dL/g. Model compound work was performed in detail to demonstrate the feasibility of the reaction for polymer formation. The thermogravimetry of the aromatic poly(benzoxazole)s showed 10% weight loss in air and nitrogen at 450–505°C and 465–535°C, respectively.