The influence of light on ageing of newsprint paper

Irradiating of groundwood paper (newsprint) by modified sunlight has a considerably high degradation effect which is manifested by yellowing, increased acidity and loss of mechanical qualities. It is shown that the lignin component of such paper is most sensitive to light Light induced oxidation reactions are of crucial importance in the degradation of lignin. Deacidification of groundwood papers with MMMC significantly inhibits the course of light induced oxidation reactions, but increases certain processes which result in a greater amount of water extractable degradation products and in lower folding endurance. Deacidified papers are very sensitive to light radiation, which significantly limits their utility far exhibition purposes. The cellulose component of groundwood paper is resistant to the degradative effect of light.