巨龙竹全组分乙酰化膜的制备与性能表征

选用云南省一种具有极大开发利用价值的大型丛生竹——巨龙竹作为研究对象,竹粉经1-甲基咪唑/二甲基亚砜(NMI/DMSO)溶剂体系预处理后,加入过量乙酸酐,得到的乙酰化原料用于制备全组分基膜材料,并引入增塑剂聚乙二醇(PEG)进一步对膜性能进行改性.经原料组分含量测定、红外光谱、紫外光谱、扫描电镜、力学性能和亲水性测定对膜材料表征分析.结果表明:乙酰化原料木质素、纤维素、半纤维素的质量分数分别为:22.3%、63.2%和13.6%,说明三大组分都得以有效利用,红外光谱进一步验证了乙酰化反应取代羟基效果明显;基膜紫外光区透过率为零,可见光区透过率也较低,但随着聚乙二醇添加量的增大,透光率增大;改性后的膜力学性能大幅提高,加入50%聚乙二醇的膜力学性能最优,拉伸强度提高了168%,伸长率提高了250%;接触角数值可以看出,聚乙二醇的添加使得膜亲水性能变好.

Preparation and Characterization of a Dendrocalamus sinicus-Based All-Component Acetate Membrane

Dendrocalamus sinicus, which is of great value for development and utilization in Yunnan Province, was selected as the research object. Bamboo powder was pretreated with an NMI/DMSO (1-methylimidazole/dimethyl sulfoxide) solvent system, and acetylation was performed by adding acetic anhydride to carry out acetylation reaction. Acetylated raw materials were used to prepare an all-component membrane and plasticizer polyethylene glycol (PEG) was used to modify the material. Through the determination of raw material composition, infrared spectroscopy, ultraviolet spectroscopy, contact angle, scanning electron microscopy and mechanical property testing, the membrane material was characterized. The contents of lignin, cellulose and hemicellulose of the acetylated raw material were shown to be 22.3%, 63.2% and 13.6% respectively, demonstrating that all the three major components of bamboo were well utilized. Fourier transform infrared (FTIR) spectroscopy indicated that the acetylation reaction had an obvious effect on the substitution of hydroxyl groups. The UV transmittance of the base film was zero, and the visible light area transmittance was also low, but with the increase in the amount of the polyethylene glycol added, the transmittance of the membrane increased. The mechanical properties of the modified film were significantly improved. The addition of 50% PEG gave the best results, with an increase in tensile strength by 168% and in elongation by 250%. Contact angle measurement proved that the addition of polyethylene glycol made the hydrophilic properties of the film better.