| Abstract:In order to deeply investigate the reason and mechanism for the difference in air permeability between hemp paper and wood paper, different hemp fiber raw materials (flax pulp and hank pulp) and wood fiber raw materials (hardwood pulp and softwood pulp) were used to prepare unfilled and filled with 10% calcium carbonate paper, respectively. Subsequently, the mechanism of the difference in air permeability performance were explored according to the analysis of the changes in the morphology of the fibers before and after beating, the distribution of the pore structure and SEM images of the finished paper, in combination with the air permeability and tightness of the finished paper. The results showed that: whether filling with calcium carbonate or not, the air permeability of hemp paper was always better than that of wood paper. Furthermore, the immediate reason why the air permeability of hemp paper was better than that of wood paper was that the looser fiber network structure of hemp paper. While the fibrillation degree of hemp fiber was lower than wood fiber in the beating process, resulting in the lower interweaving compactness level of hemp fiber, which might be the root cause of the difference in air permeability between hemp paper and wood paper. This study aims to provide some theoretical basis and reference for regulating the air permeability of paper. |