Induction period for a decrease in molecular weight of polyvinylpyrrolidone by ball-milling in various kinds of atmosphere in the presence of organic and inorganic powders.

DOI Web Site

この論文をさがす

抄録

Polyvinylpyrrolidone (PVP) was ball-milled in nitrogen in the presence of chloranil, vitamin K3, acridine, phenothiazine, p-hydroquinone, barbituric acid, white alundum, silica sands, zinc oxide, sodium chloride, activated charcoal or talc. An induction period of 20-120 hours, at the time when molecular weight of PVP began to decrease, was observed in case of ball-milling PVP in the presence of Vitamin K3, acridine, phenothiazine, zinc oxide or talc. The induction period was longer than 200 hours in the presence of chloranil or the granules of activated charcoal. The induction period decreased by the presence of oxygen or the small quantity of the vapor of distilled water or the aqueous solution of hydrogen peroxide in the ball-milling atmosphere. The electron spin resonance (ESR) spectra of the mixtures of PVP and the additive showed that interaction was caused between them by ball-milling. When a large induction period was observed, the intensity of the signal in the ESR spectra increased slightly at the first stage of ball-milling and remarkably by ball-milling after the lapse of the induction period. The scanning electron microscopic photographs of the ball-milled mixtures suggested that the particles of the additive filled in the pores on the surface of PVP and got into the particles of PVP gradually by ball-milling. The molecular weight and the particle size of PVP seemed to begin to decrease after the particles of the additive filled in the pore thoroughly by ball-milling, when a long induction period was observed.

収録刊行物

キーワード

詳細情報 詳細情報について

問題の指摘

ページトップへ