Preparation of carboxymethyl cellulose from tea stalk and its use as a paper-strengthening agent

Abstract Tea stalk was used for producing carboxymethyl cellulose (CMC), and a response surface methodology was used to model effective factors relative to the degree of substitution (DS). The optimum values of the independent variables were an alkalization time of 107 min, monochloroacetic acid at 3.11 g, and an etherification time of 171 min, at which the CMC had a DS of 0.668. The yield of CMC in optimization condition was 75.9 %. The optimized CMC was in a good agreement with the commercial CMC, as based on Fourier transform infrared spectroscopy and X-ray diffractometry analyses. The optimized CMC was used to enhance paper strength, and with economic factors and paper strength enhancement taken into account, the appropriate amount of optimized CMC was determined to be approximately 0.3 %. When the amount of optimized CMC was at 0.3 %, the tensile index, burst index, tearing index, and folding endurance were 26.7 N m/g, 1.0\hspace{0.1667em}\text{kPa}\hspace{0.1667em}{\text{m}²}/\text{g}, 12.1\hspace{0.1667em}\text{mN}\hspace{0.1667em}{\text{m}²}/\text{g}, and 2.0, respectively. Together, these results indicated that the optimized CMC exhibited comparable paper strengthening properties relative to that of commercially available CMC.