Recent progress on organosilicon coatings deposited on bleached unrefined Kraft paper by non-thermal plasma process at atmospheric pressure

In future years, recent progress in plasma processing using non-thermal plasmas at atmospheric pressure will be used to improve numerous natural by-product applications, including those based on materials derived from woody biomass. This work provides a detailed study of the morphological and chemical modification of bleached, unrefined Kraft paper obtained in homogeneous, plane-to-plane dielectric barrier discharges at atmospheric pressure in the presence of 2,4,6,8-tetramethylcyclotetrasiloxane (TMCTS) precursor. High-resolution SEM images highlight the presence of micro and nanoscale fibrous structures on the raw surface as well as their influence on the heterogeneous growth dynamics of the organosilicon film. Through FTIR and XPS analysis, it is further demonstrated that it is possible to take advantage of the natural porous structure of the cellulosic substrate to obtain both surface and volume treatment. Such analysis further revealed a low plasma-assisted fragmentation of the TMCTS precursor and a partial oxidation of the TMCTS precursor fragments during the plasma deposition process to form a Si-O-Si network. Over the range of experimental conditions investigated, wettability with water measurements reveal significant water repellency of the naturally hydrophilic cellulosic substrate. For sufficiently thick coatings, the plasma-processed materials remained unchanged even after 20 h of water immersion, a very promising result to reduce the degradation of ligno-cellulosic materials in humid and aggressive conditions.