Chitin nanocrystals prepared by TEMPO-mediated oxidation of α-chitin
Chitin nanocrystals prepared by TEMPO-mediated oxidation of α-chitin
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DOI：
10.1021/bm700966g
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发表时间：
2008-01-01
影响因子：
6.2
通讯作者：
Isogai, Akira
中科院分区：
文献类型：
--
作者：
Fan, Yirnin;Saito, Tsuguyuki;Isogai, Akira
以2，2，6，6-四甲基哌啶-1-氧基自由基(TEMPO)为催化剂，在pH为10的条件下氧化α-甲壳素，再经超声波处理，成功制备了分散在水中的甲壳素纳米晶。当助氧化剂NaClO的加入量为5.0 mm o l/g甲壳质时，速氧化甲壳素中水不溶部分的质量分数为90%，其羧酸盐含量达到0.48 m o l/g，由于速氧化甲壳素的结晶度与原甲壳质的结晶度一样高，故可认为速氧化甲壳素中的C6羧酸基只存在于甲壳质微晶表面。经TEMPO氧化的几丁质未发生N-脱乙酰基反应。将氧化后的甲壳素在水中进行超声波处理，得到的甲壳素纳米晶大多是个性化的，平均长度为340 nm，平均宽度为8 nm。
Chitin nanocrystals dispersed in water were successfully prepared by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) mediated oxidation of alpha-chitin in water at pH 10 under specific conditions, followed by ultrasonic treatment. When the amount of NaClO added as co-oxidant in the oxidation was 5.0 mmol/g of chitin, the weight percentage of the water-insoluble fraction in the TEMPO-oxidized chitin was 90%, and its carboxylate content reached 0.48 mmol/g. Since the TEMPO-oxidized chitin thus prepared had a crystallinity as high as that of the original alpha-chitin, the C6 carboxylate groups formed by TEMPO-mediated oxidation can be regarded as being present only on the chitin crystallite surfaces. No N-deacetylation occurred on the TEMPO-oxidized chitins. When the TEMPO-oxidized chitin was subjected to ultrasonic treatment in water, mostly individualized chitin nanocrystals were obtained, and the average nanocrystal length and width were 340 and 8 nm, respectively.