1994 Volume 48 Issue 12 Pages 1621-1630
Handsheets containing hardwood kraft pulp (LBKP) and either bacterial or algal cellulose were prepared, and their mechanical and optical properties were studied in terms of their reinforcing effects on fiber network in sheet. Bacterial and algal celluloses were disintegrated to form a fine fiber suspension, and were added to paper stock in place of LBKP with 0-100%. The reinforcing effect of bacterial cellulose in LBKP sheet resulted in increases of physical properties such as Young's modulus, tensile strength, folding endurance and dimensional stability, although opacity decreased with bacterial cellulose content in handsheet. Handsheets containing algal cellulose had almost no improvement in tensile strength and folding endurance, although they showed improved dimensional stability and high Young's modulus. The difference in physical behavior between bacterial and algal celluloses, in spite of similar structure of fine fibrils, can be explained by the morphological difference between them. The microfibrils of algal cellulose seemed stiff and straight, while those of bacterial cellulose showed flexible, twisting ribbon-like form. Therefore, bacterial cellulose microfibrils are more likely to entangle with LBKP fibers than those of algal cellulose in handsheets, and thus they may contribute to improvements in the mechanical properties.