Strengthening tensile strength of wet and dry layer of paper from chemical-mechanical pulp by cellulose nanofibers and PAE

Some paper industries use long fiber pulp (LFP) and or wet strength resins to increase resistance and prevent web breakings during production. In this study, it was investigated the role of polyamidoamine epichlorohydrin (PAE) in combination with cellulose nanofibers (CNF) compared to LFP in improving wet and dry layer of paper tensile strength of chemi-mechanical pulp (CMP) by handsheet making with grammage of 130 g/m2. First, cellulose nanofibers (3% and 4%) with PAE (0.7% and 1%) and long fiber pulp (LFP) were added to the pulp suspension and then handsheet paper was made. The dewatering period was measured when making handsheet. Then, the tensile strength was measured after drying to 35, 55, 75 and air-dried dryness (%) during drying within handsheet making. Results showed, wet layer of paper with dryness of 35 and 55% treated with 3% CNF and 7% PAE showed tensile strength close to samples with 20% LFP and in 75% dryness showed higher tensile strength than treatments with LFP. Generally, treatments with CNF and PAE had wet layer of paper tensile strength values during production the same as or more than long fiber pulp, although the water drainage rate will be decrease.