*Article* **Effects of Raw Material Source on the Properties of CMC Composite Films**

**Yao Yao 1,†, Zhenbing Sun 1,†, Xiaobao Li 1,†, Zhengjie Tang 1, Xiaoping Li 1,2,\*, Jeffrey J. Morrell 3,\*, Yang Liu 4, Chunli Li <sup>1</sup> and Zhinan Luo <sup>1</sup>**


**Abstract:** Sodium carboxymethyl cellulose (CMC) can be derived from a variety of cellulosic materials and is widely used in petroleum mining, construction, paper making, and packaging. CMCs can be derived from many sources with the final properties reflecting the characteristics of the original lignocellulosic matrix as well as the subsequent separation steps that affect the degree of carboxy methyl substitution on the cellulose hydroxyls. While a large percentage of CMCs is derived from wood pulp, many other plant sources may produce more attractive properties for specific applications. The effects of five plant sources on the resulting properties of CMC and CMC/sodium alginate/glycerol composite films were studied. The degree of substitution and resulting tensile strength in leaf-derived CMC was from 0.87 to 0.89 and from 15.81 to 16.35 MPa, respectively, while the degree of substitution and resulting tensile strength in wooden materials-derived CMC were from 1.08 to 1.17 and from 26.08 to 28.97 MPa, respectively. Thus, the degree of substitution and resulting tensile strength tended to be 20% lower in leaf-derived CMCs compared to those prepared from wood or bamboo. Microstructures of bamboo cellulose, bamboo CMC powder, and bamboo leaf CMC composites' films all differed from pine-derived material, but plant source had no noticeable effect on the X-ray diffraction characteristics, Fourier transform infrared spectroscopy spectra, or pyrolysis properties of CMC or composites films. The results highlighted the potential for using plant source as a tool for varying CMC properties for specific applications.

**Keywords:** Chinese pine wood; pine needles; bamboo culms; bamboo leaves; industrial hemp hurd; CMC; DS; mechanical properties; TG; XRD; FTIR
