Effects of CNCC on the mechanical properties of PVA fiberpaper As can be seen from Curve A in Fig. 3, with the increase of CNCC dosage from 0.1% to 1.0%, the air permeability of PVA fiber papersheet decreased continuously from 940 mL/s to 845 mL/s, showing a different change tendency from that of cellulosic paper sheet discussed above. One can assume that there were more sufficient gap between PVA fibers than cellulosic fibers, therefore allowed for the filling of higher dosage of CNCC, which might be responsible for the continuously decreased air permeability with the increased dosageof CNCC.For Curve B in Fig. 3, increasing the CNCC dosage led to thein creased tear index of PVA fiber paper. In the absence of CNCC,the tear index was 0.54 mN m2/g, then increased to 0.9 mN m2/g ata CNCC dosage of 1.0%, showing a percentage increase of 67.29%.Fig. 4. Effect of CNCC dosage on the tensile index of PVA fiber paper.This result provided direct evidence that CNCC addition was effec-tive in reinforcing the mechanical properties of PVA fiber paper. Thereason for that can be mainly attributed to the abundant carboxylgroups on the surface of CNCC, which facilitates the combining of itsown hydrogen bonding or the hydroxyl groups of PVA fiber to formhydrogen-densely reticular structure, thereby resulting in the sig-nificantly improved tear index of PVA fiber paper (Li, Renneckar, &Barone, 2010). Similar result was presented in the literature (Uddinet al., 2011a; Uddin et al., 2011b). In the previous study, NCC wasused for reducing fibrillation of PVA fibers, where oriented NCC was put inside in the inter-fibrillar areas and found to automatically form lateral interlinks between fibrils by hydrogen bondingwhich made fibrils a relatively complete unit and improved the tear index of PVA fibers.