Dynamic mechanical studies of a highly filled composite structure: A lightweight coated paper

Abstract

SYNOPSISA composite sandwich structure, consisting of a paper sheet as a middle layer and two porous coating layers of a highly filled acrylate-styrene-butadiene copolymer, has been studied by means of a dynamic mechanical test in torsion. Stiffness and mechanical damping, tan 6, were recorded over the temperature region where the latex polymer exhibits a glass transition. The mechanical damping decreases with increasing filler content in the coating. Variations in the thickness of the coating layers did not influence the mechanical damping. The glass transition temperature of the latex polymer increases with increasing volume fraction of filler at high filler contents as an effect of filler-matrix interaction. The outer layers partly penetrate into the middle layer, as indicated by thickness measurements on the coated paper. A theoretical comparison of the peak heights of the mechanical damping using lamination theory shows a discrepancy in the experimental results. If penetration of the outer layer is allowed for, i.e., if using a thicker outer layer of the composite in the calculations, a favorable correlation between the theoretical and the experimental results is obtained.

Response of Paper Properties to Changes in Moisture Content and Temperature

“…There is a noticeable difference between calendered papers which show a large increase in roughness, particularly papers based on mechanical pulps, and uncalendered papers based on mechanical pulp which show no increase or those based on chemical pulp which showed only a marginal increase in roughness ( 124).' In the case of papers of mechanical pulp, this interaction with water also results in a substantial increase in the thickness of the paper ( 124 ) which is also evident in the coating of LWC furnishes (97). For chemical pulps no detectable increase in thickness was noticed in contact with water (1 4).…”