Recycled Paper Additive for Wood-Polymer Composite: Preparation and Characterization

The recycling of paper and paperboard waste for obtaining powder cellulose has a positive impact on environmental and economic benefits due to its possibility to be applied in various fields of industry, including the fabrication of wood-polymer composite^1,2. The extraction of cellulose from cellulose-containing wastes can be carried out by their mechanical disintegration with acid or alkali hydrolysis. In comparison with the known method³ the proposed method can be realized under more gentle conditions. For this aim, recycled de-inked waste paper was cut into small pieces (d < 5 mm) which were soaked in 0,05% hydrochloric solution at hydromodulus 1/20 (paper/water) for 2 hours at the intensive mechanical stirring for paper pieces disintegration. After soaking, the excessive water was pressed, and the disintegrated paper mass was dried, at first, at 60 °C for 16 hours and then at 120 °C for 2 hours. After drying, the paper mass was milled in a planetary mill for 15 minutes at a moderate rotation speed. The obtained cellulose particles were characterized by physicochemical properties. It was found, that obtained recycled paper particles (RPAP) had a similar contact angles with water compared to reference cellulose powder. However, polarity of RPAP was 20,5%, but of reference cellulose – 43,5%. RPAP could be characterized as more amorphous than cellulose because its crystallinity index was 61%, but reference cellulose powder – 81%. Using laser granulometry, it was found, that 99% of particles were less than 200 μm, and 90% of particles were less than 140 μm.