2.2. Extraction and surface-only modification of BC via organic acid esterification
BC was extracted from nata-de-coco, rinsed, blended, homogenized, purified to remove any remaining microorganisms and soluble polysaccharides [29], followed by multiple centrifugation, rinsing and homogenization cycles to return the aqueous dispersion of BC to neutral pH, according to our previous work [28,30]. BC was then modified via an organic acid esterification procedure, described in detail [28]. Briefly, dispersions of BC were solvent exchanged into pyridine from water through methanol and esterified with either hexanoic acid or dodecanoic acid in the presence or p-toluenesulfonyl chloride. After the reaction, the reaction medium was quenched with ethanol and the modified cellulose product rinsed several times with ethanol and solvent exchanged into dimethyl carbonate [28]. Neat and modified BC were dispersed in water and dimethyl carbonate respectively at a concentration of 0.4% (g mL1), flash frozen in Petri dishes by immersion in liquid nitrogen and subsequently freeze-dried (Edwards Modulyo freeze
dryer, UK). BC functionalised with hexanoic and dodecanoic acid are here termed C6-BC and C12-BC, respectively.
2.2. Extraction and surface-only modification of BC via organic acid esterificationBC was extracted from nata-de-coco, rinsed, blended, homogenized, purified to remove any remaining microorganisms and soluble polysaccharides [29], followed by multiple centrifugation, rinsing and homogenization cycles to return the aqueous dispersion of BC to neutral pH, according to our previous work [28,30]. BC was then modified via an organic acid esterification procedure, described in detail [28]. Briefly, dispersions of BC were solvent exchanged into pyridine from water through methanol and esterified with either hexanoic acid or dodecanoic acid in the presence or p-toluenesulfonyl chloride. After the reaction, the reaction medium was quenched with ethanol and the modified cellulose product rinsed several times with ethanol and solvent exchanged into dimethyl carbonate [28]. Neat and modified BC were dispersed in water and dimethyl carbonate respectively at a concentration of 0.4% (g mL1), flash frozen in Petri dishes by immersion in liquid nitrogen and subsequently freeze-dried (Edwards Modulyo freezedryer, UK). BC functionalised with hexanoic and dodecanoic acid are here termed C6-BC and C12-BC, respectively.
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