Rachtanapun Pornchai, Jantrawut Pensak, Klunklin Warinporn, Jantanasakulwong Kittisak, Phimolsiripol Yuthana, Leksawasdi Noppol, Seesuriyachan Phisit, Chaiyaso Thanongsak, Insomphun Chayatip, Phongthai Suphat, Sommano Sarana Rose, Punyodom Winita, Reungsang Alissara, Ngo Thi Minh Phuong
Faculty of Agro-Industry, School of Agro-Industry, Chiang Mai University, Chiang Mai 50100, Thailand.
The Cluster of Agro Bio-Circular-Green Industry (Agro BCG), Chiang Mai University, Chiang Mai 50100, Thailand.
Polymers (Basel). 2021 Jan 22;13(3):348. doi: 10.3390/polym13030348.
Bacterial cellulose from nata de coco was prepared from the fermentation of coconut juice with for 10 days at room temperature under sterile conditions. Carboxymethyl cellulose (CMC) was transformed from the bacterial cellulose from the nata de coco by carboxymethylation using different concentrations of sodium hydroxide (NaOH) and monochloroacetic acid (MCA) in an isopropyl (IPA) medium. The effects of various NaOH concentrations on the degree of substitution (DS), chemical structure, viscosity, color, crystallinity, morphology and the thermal properties of carboxymethyl bacterial cellulose powder from nata de coco (CMCn) were evaluated. In the carboxymethylation process, the optimal condition resulted from NaOH amount of 30 g/100 mL, as this provided the highest DS value (0.92). The crystallinity of CMCn declined after synthesis but seemed to be the same in each condition. The mechanical properties (tensile strength and percentage of elongation at break), water vapor permeability (WVP) and morphology of CMCn films obtained from CMCn synthesis using different NaOH concentrations were investigated. The tensile strength of CMCn film synthesized with a NaOH concentration of 30 g/100 mL increased, however it declined when the amount of NaOH concentration was too high. This result correlated with the DS value. The highest percent elongation at break was obtained from CMCn films synthesized with 50 g/100 mL NaOH, whereas the elongation at break decreased when NaOH concentration increased to 60 g/100 mL.
椰果中的细菌纤维素是在无菌条件下，将椰子汁发酵10天，于室温下制备而成的。通过在异丙醇（IPA）介质中使用不同浓度的氢氧化钠（NaOH）和一氯乙酸（MCA）进行羧甲基化反应，将椰果中的细菌纤维素转化为羧甲基纤维素（CMC）。评估了不同NaOH浓度对椰果羧甲基细菌纤维素粉末（CMCn）的取代度（DS）、化学结构、粘度、颜色、结晶度、形态和热性能的影响。在羧甲基化过程中，最佳条件是NaOH用量为30 g/100 mL，因为此时DS值最高（0.92）。合成后CMCn 的结晶度下降，但在每种条件下似乎相同。研究了使用不同NaOH浓度合成的CMCn薄膜的机械性能（拉伸强度和断裂伸长率百分比）、水蒸气透过率（WVP）和形态。用30 g/100 mL NaOH浓度合成的CMCn薄膜的拉伸强度增加，但当NaOH浓度过高时拉伸强度下降。这一结果与DS值相关。用50 g/100 mL NaOH合成的CMCn薄膜的断裂伸长率最高，而当NaOH浓度增加到60 g/100 mL时，断裂伸长率降低。
