纳米化竹粉/羧甲基纤维素复合膜材料制备及性能研究

Preparation and properties of bamboo nano powder/carboxymethyl cellulose composite film

为充分利用竹材资源,促进竹材的高值利用,笔者以氯乙酸作为醚化剂,对竹粉进行羧甲基化处理,在水中分离得到水溶性的纳米化竹粉(bamboo nano powder,NB),并与羧甲基纤维素(carboxymethyl cellulose,CMC)复合成膜,用于食品包装等领域。经扫描电镜显示其形态为颗粒状,且测得尺寸约为50 nm。与羧甲基纤维素(carboxymethyl cellulose,CMC)经流延法复合成膜。通过X-射线衍射仪、电子万能试验机、扫描电镜、傅里叶红外光谱仪、紫外分光光度计对制备的纳米复合薄膜进行结构、形貌、吸潮率和力学性能表征。结果表明,当NB与羧甲基纤维素水溶液的体积分数从0%增至20%时,弹性模量由2 397 MPa增至3 932 MPa,增加了1 535MPa,机械性能提高,但断裂伸长率降低;当体积分数高于20%,复合膜的力学性能呈现下降趋势。纳米化竹粉能够提高羧甲基纤维素膜的力学性能,降低吸潮性,可作为添加剂用于包装材料的制备。

Nanocrystalline cellulose is renewable and biodegradable, also has excellent mechanical properties. It can be used as the reinforcing material for various polymer matrix and has broad application prospects. Carboxymethyl cellu- lose （CMC） is one of the important derivatives of cellulose and has been widely used as food packaging materials due to its biological activities. Bamboo is a fast grow plant and widely distributed source. In this paper, bamboo powder was treated by chloroacetic acid as an etherification agent. Water-soluble bamboo nano powder （NB） was then isolated after the treatment. The morphology of the resulting NB obtained by scanning electron microscopy indicated that the NB is granular with the size about 50 nm. The NB/CMC cornposited film was prepared by casting method and characterized by X ray diffraction, electronic universal testing machine, scanning electron microscope, and infrared spectrometer to investigate its structure, morphology, moisture absorption and mechanical properties. It was found that when the volume fraction of the NB and CMC increased from 0% to 20%, the elastic modulus of the composite film increased from 2 397 MPa to 3 932 MPa, while the elongation at break decreased. When the volume fraction of the NB was higher than 20%, the mechanical properties of the composite film decreased. The results indicate that the bamboo nano powder can improve the mechanical properties and reduce the moisture absorption of the composite film, which makes it a candidate as an additive for the preparation of packing materials.