The current structural models of the cellulose microfibril as well as its mechanical and thermal properties are reviewed. The cellulose microfibril can be considered as a single thin and long crystalline entity with highly anisotropic physical properties. The contribution and limit of different methods employed such as electron microscopy, infrared spectroscopy, X-ray scattering and diffraction, solid state nuclear magnetic resonance spectroscopy, and molecular modeling are also discussed.

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Structure and properties of the cellulose microfibril

There is an increasing awareness that the separation of over-lapping bands by the mathematical technique of curve fitting offers many pitfalls and should not be undertaken lightly. This review discusses critically the various factors involved, with particular reference to vibrational band systems; other types of overlapping band systems encountered in analytical work are considered in less detail. Five parameters are involved: the number of component bands, their positions, shapes and widths, and the form of the baseline. Curve fitting, by a least squares optimization method to a suitable goodness of fit criterion, is considerably facilitated if approximate values for some of the parameters are known at the outset. The methods available for peak finding are discussed and, although not free from problems, are reasonably effective. Similarly, band shapes can usually be defined semiquantitatively. However, it is seldom possible to obtain prior information on band widths; these should be determined during the curve fitting calculations. Although statistical goodness of fit criteria are available they should be used in conjunction with a visual plot, to locate any regions of poor fit. Furthermore, the overriding consideration must always be that the computer fit is plausible in terms of acceptable chemical species for the system being examined.

The Scope and Limitations of Curve Fitting

Dissolution or extraction of crustacean shells using ionic liquids to obtain high molecular weight purified chitin and direct production of chitin films and fibers

Microstructural, physico-chemical and mechanical characterisation of Sansevieria cylindrica fibres – An exploratory investigation

A.M. Hindeleh

Papers

Crystallinity and crystallite size measurement in polyamide and polyester fibres

Crystallinity and crystallite size measurement in cellulose fibres: 1. Ramie and Fortisan

Crystallinity and crystallite size measurement in cellulose fibres: 2. Viscose rayon

Effects of annealing on the crystallinity and microparacrystallite size of Kevlar 49 fibres

An empirical estimation of Scherrer parameters for the evaluation of true crystallite size in fibrous polymers