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以溶解级木浆作为原料,通过TEMPO(2,2,6,6四甲基哌啶1氧化物自由基)/NaClO/NaClO_2氧化体系对纤维素C-6羟基进行氧化,经过乙酰化处理后制备出C-6位含羧基的氧化纤维素醋酸酯。用红外光谱(IR)、X-射线衍射(XRD)和核磁共振(NMR)等手段表征了产物的结构,用热重分析(TGA)和差示扫描量热法(DSC)测试了产物的热性能。结果表明:所合成氧化纤维素醋酸酯的C-6位羧基取代度为0.15,乙酰基取代度为2.72(其中C 2为0.93、C-3为0.98、C 6为0.81)且取代均匀性较好;用C-6羟基的选择性氧化预处理可实现纤维素的可控酯化;产物能溶于DMSO(二甲基亚砜);产物的晶型由纤维素Ⅰ型转变成纤维素Ⅱ型。氧化纤维素醋酸酯在185℃发生玻璃化转变,在257℃熔融。乙酰基的接入,使产物的热塑性提高。
The dissolution of wood pulp as raw material, by TEMPO (2,2,6,6 tetramethylpiperidine 1 oxide free radical) / NaClO / NaClO 2 oxidation of cellulose C-6 hydroxyl oxidation, after acetylation C-6 carboxyl-containing oxidized cellulose acetate was prepared. The structure of the product was characterized by infrared spectroscopy (IR), X-ray diffraction (XRD) and nuclear magnetic resonance (NMR). The thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) performance. The results showed that the degree of substitution of C-6 carboxyl group was 0.15 and the degree of substitution of acetyl group was 2.72 (C 2 was 0.93, C-3 was 0.98, C 6 was 0.81) Good; selective oxidation with C-6 hydroxyl preconditioning can be controlled esterification of cellulose; the product can be dissolved in DMSO (dimethyl sulfoxide); product of the crystalline form of cellulose type Ⅰ into cellulose Ⅱ type. Oxidized cellulose acetate undergoes a glass transition at 185 ° C and melts at 257 ° C. Acetyl access, so that the thermoplastic product improved.