Structure and Mechanical Properties of Papers Containing Ground Wasted Tealeaves

Abstract

Wasted Green tea leaves were ground by different methods and papers containing the ground wasted Green tea leaves were prepared. The ground wasted Green tea leaves and the papers containing the ground wasted Green tea leaves were subjected to Scanning Electron Microscopy for morphological observation. The observation revealed that a mass-colloider ground wasted Green tea leaves to very thin films. As the clearance of the mass-colloider was widened from 40 μm to 150 μm, the ground wasted Green tea leaves somewhat increased in thickness and turned into partially folded structures. In addition, after ground, the wasted Green tea leaves showed spiral vessels and vascular bundles extended into coil shapes by shear at the grinding. In contrast, wasted Green tea leaves ground with a ball mill were lumps ranging a few to 400 μm in size. The ground wasted Green tea leaves were used to prepare papers containing wasted Green tea leaves, which were observed. The observation revealed that papers containing wasted Green tea leaves ground with the mass-colloider had a layered structure in which the thin films of wasted Green tea leaves were layered in tight adhesion with networks of pulp fibers. In contrast, papers containing wasted Green tea leaves ground with the ball mill had a coarse structure in which lumps of the wasted Green tea leaves were buried in the network of pulp fibers. In addition, the papers containing wasted Green tea leaves ground by the two different methods were examined for tensile strength and bursting strength. The examination revealed little differences resulting from the different grinding methods, the mass-colloider and the ball mill, or from difference in the clearance of the mass-colloider. The result showed that the mechanical properties were mainly controlled by the pulp fibers in the papers containing wasted Green tea leaves and the wasted Green tea leaves made little contribution to the mechanical properties. On the other hand, papers containing wasted Green tea leaves were lower in stiffness than 100wt% pulp papers; especially papers containing wasted Green tea leaves ground with the ball mill were very soft. Furthermore, an examination of papers containing wasted Green tea leaves for permeability revealed that papers containing wasted Green tea leaves ground with the ball mill had much higher permeability than 100wt% pulp papers.