newsprint paper

Ingredients

mechanically bleached groundwood (55%), bleached sulphite pulp (20%), catch trash fibres (15%), clay (10%)

Preparation Steps

Original Recipe Text

To analyze the paper, cellulose tricarbanilates (CTC) were prepared. 1 mL of phenylisocyanate was added to 20 mg of dry sample in 6 mL of dry pyridine. The mixture was heated for 6 h at 110 °C. The resulting clear yellow viscous solution was cooled, and excess phenylisocyanate was decomposed by adding 2 mL of methanol. The solution was poured into 150 mL of stirred methanol. The precipitate was washed with water containing acetic acid, then with water and methanol, and dried at 50 °C in a vacuum oven. The white fibrous precipitate was dissolved in dioxane and re-precipitated into water. A second precipitation from dioxane into water yielded the pure triester (p. 1511).

Evidence

"A series of accelerated ageing experiments was performed according to ASTM D 6819-02 method on newsprint paper (grammage planar density: 45 g m−2, liquor pH: 4.5–5.0) containing mechanically bleached groundwood (55%), bleached sulphite pulp (20%), catch trash fibres (15%) and clay (10%)."

Remarks

The study investigates the alteration of newsprint paper during accelerated ageing at 98 °C for up to 60 days. In the early stages, cellulose depolymerization occurs homogeneously, primarily via hydrolysis. In later stages, oxidation and crosslinking reactions become more prominent (p. 1509). The initial polydispersity (PD) of the unaged sample was 7.20, primarily due to the presence of hemicelluloses, which exhibit a bimodal MWD curve (p. 1512). The decrease in the hemicelluloses-to-glucose ratio was found to be linear (y = -0.0028x + 0.2132) with a high correlation coefficient (p. 1512).