![]() If biological specimens such as the tobacco mosaic virus (TMV), T4-phage, collagen, etc. Morphologies of natural polymers other than cellulose have also been studied by electron microscopy. 333, 334 Lattice images appear to be useful in estimating the lateral crystallite size and discussing the existence of axial periodicity in cellulose. 330, 331 whilst Revol 332 obtained imaging for Valonia cellulose, and very recently imaging for bacterial and ramie celluloses was obtained by Kuga et al. Lattice imaging of cellulose crystal was achieved by Sugiyama et al. 329 Properly defocused images suggested the existence of a certain periodical structure (about 6 nm in periodicity) along the protofibril axis. Recently the effect of defocusing on the image contrast in TEM of negatively stained protofibrils of ramie cellulose was discussed on the basis of the defocus dependence of the phase contrast transfer function sin χ (see Section 34.3) using the OD technique 328 and the digital correlation method. The lateral crystallite size, namely the width or thickness of the microfibril of natural cellulose, is one of the important features of this polymer. ![]() Masaki Tsuji, in Comprehensive Polymer Science and Supplements, 1989 34.5.4 Natural PolymersĬellulose crystals have been extensively studied by electron microscopy. ![]()
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