LIQUID CRYSTAL SYSTEMS FROM FIBRILLAR POLYSACCHARIDES
LIQUID CRYSTAL SYSTEMS FROM FIBRILLAR POLYSACCHARIDES
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DOI：
10.1038/184632a0
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发表时间：
1959-01-01
期刊：
影响因子：
64.8
通讯作者：
WALTER, NM
中科院分区：
文献类型：
--
作者：
MARCHESSAULT, RH;MOREHEAD, FF;WALTER, NM
通过在强硫酸(952克/升)中在30或40℃下水解24小时来制备纤维素微晶的中性水悬浮液。已描述过1。通过处理20克甲壳质微晶颗粒制备类似的悬浮液。从蟹壳中纯化甲壳素 1 小时。 750 毫升。回流下加入2.5N盐酸。然后，倒出过量的酸并添加蒸馏水。在此阶段，几丁质水解产物本质上仍然是沉淀物，并且当它通过“Minisonic”均质器（Sonic Eng. Corp.，斯坦福德，康涅狄格州）三次时，其完全处于酸性一侧。通过该处理，获得稳定的各向同性悬浮液并且pH升至3.5。 pH值的上升可能是由于从微晶内部释放出一些未乙酰化的氨基，这些氨基与质子络合形成微晶表面。甲壳素被认为是 N-乙酰基-d-葡萄糖胺的聚合物，其中游离 NH2 基团的存在并不令人意外，因为纯化过程涉及可以皂化乙酰基的碱性条件。稳定悬浮液的电子显微照片显示存在与纤维素微晶尺寸相似的棒状颗粒2。
THE preparation of a neutral aqueous suspension of cellulose crystallites by hydrolysis in strong sulphuric acid (952 gm./l.) at 30 or 40° C. for 24 hr. has been described1. A similar suspension of crystallite particles of chitin was prepared by treating 20 gm. of purified chitin from crab shells for 1 hr. in 750 ml. of 2.5Nhydrochloric acid under reflux. Afterwards, the excess acid was decanted and distilled water was added. At this stage, the chitin hydrolysate was still essentially a sediment and was well on the acid side when it was given three passes through a ‘Minisonic’ homogenizer (Sonic Eng. Corp., Stamford, Conn.). From this treatment, a stable isotropic suspension was obtained and thepH had risen to 3.5. The rise inpH is probably due to release, from within the crystallites, of some unacetylated amino-groups which complexed with a proton to giveat the crystallite surfaces. The presence of free NH2groups in chitin, which is supposed to be a polymer of N-acetyl-d-glucosamine is not unexpected since purification procedures involve alkaline conditions which can saponify acetyl groups. Electron micrographs of the stable suspension show the presence of rod-like particles of similar dimensions to the cellulose crystallites2.