Fibre lattices

Itaconic acid Itaconic anhydride Artificial glass, resins fibres, lattices, detergents, bioactive compounds Willke and Vorlop, 2001 Reddy and Singh, 2002 Fevinson etal., 2006... 

Quaternary Ga In j.As jPj, grown on InP is of major importance to fibre-optic communications. In quaternary compounds, both the gap and the lattice constant can be tailored by changing the chemical composition. In thick layers, in order to avoid the generation of strain-induced defects, care must be taken in adjusting the ratio of x and v to maintain the lattice-matched composition x = 2.2v. The available gaps range from 1.34 eV in InP to -0.75 eV in... 

We will confine ourselves to those applications concerned with chemical analysis, although the Raman microprobe also enables the stress and strain imposed in a sample to be examined. Externally applied stress-induced changes in intramolecular distances of the lattice structures are reflected in changes in the Raman spectrum, so that the technique may be used, for example, to study the local stresses and strains in polymer fibre and ceramic fibre composite materials. 

In order to achieve efficient build-up to heavy depths when dyeing cellulose acetate at 80 °C it is customary, particularly for navy blues, to use a mixture of two or more components of similar hue. If these behave independently, each will give its saturation solubility in the fibre. In practice, certain mixtures of dyes with closely related structures are 20-50% less soluble in cellulose acetate than predicted from the sum of their individual solubilities [87]. Dyes of this kind form mixed crystals in which the components are able to replace one another in the crystal lattice. The melting point depends on composition, varying gradually between those of the components, and the mixed crystals exhibit lower solubility than the sum of solubilities of the component dyes [88]. Dyes of dissimilar molecular shape do not form mixed crystals, the melting point curve of the mixture shows a eutectic point and they behave additively in mixtures with respect to solubility in water and in the fibre. 

This done, consider the other layer lines on the photograph. A reciprocal lattice rotation diagram is prepared as before from the and f values of all the spots. If row lines are exhibited, then the remaining axis of the reciprocal lattice is normal to the zero-level not, as in Fig. 89 in other words, the crystals are monoclinic with their b axes parallel to the fibre axis. It is again necessary to remember that one or both reciprocal axes of the zero-level net may have to he halved to account for all the points on other levels. 

From what has been stated above it is clear that there is a similarity in concepts over a considerable range of scale as between, on the one hand real crystals where the elements are atoms, through ordered phase materials such as copolymers, where the elements are amorphous but in a crystalline lattice, to macro-crystalline materials such as composites. Since a great deal of work has been done in recent years on the properties of composites, in particular fibre composites, it is worth examing the generality of the results obtained particularly in the respect of molecular composites such as semicrystalline polymers and copolymers. 

In three dimensions a treatment, approaching exactness of the short fibre array was made by Smith and Spencer52 j which hexagonal packing was assumed but the hexagonal unit cell replaced by a composite circular cylinder. Numerical analysis of the cubic lattice of spheres was made by Broutman and Agarwal53 . 

X-ray diffraction patterns from fibres generally contain a few closely overlapping peaks, each broadened by the contributions of crystallite size, crystallite-size distribution, and lattice distortion. In order to achieve complete characterisation of a fibre by X-ray methods, it is first necessary to separate the individual peaks, and then to separate the various profile-broadening contributions. Subsequently, we can obtain measures of crystallite size, lattice distortion and peak area crystallinity, to add to estimates of other characteristics obtained in complementary experiments. 

Methods for estimating lattice distortion generally require two or more orders of a particular reflection to be present, and most polymers have only one order available. A method for estimating both crystallinity and lattice disorder, which does not need higher orders of a reflection, and indeed takes into account the whole of the diffraction trace, is that due to Buland (27). This method has been applied to many different fibres by Sotton and his colleagues, who have discussed their results both here (28) and elsewhere (12). The major problem with Ruland s method is that an arbitrary separation of the crystalline scatter from the non-crystalline scatter must be made other restrictions are that the method cannot be used to measure crystallite size and cannot give any indication of the presence of paracrystalline or intermediate-phase material. 

New methods of computational analysis will be sought in order to provide simultaneous measures of crystallinity, crystallite-size and lattice distortion in fibrous polymers from X-ray diffraction patterns, but these must pass the test of application to fibres which can be partly characterized by means of electron-microscopy. 

The entire installation is finished with a carpet of synthetic grass, which comprises usually a woven polypropylene lattice in which tufts of green polypropylene fibre or filament are fixed. The lattice is sealed on the under-side with a bonded film—which keeps the tufts in place and may be made from polyethylene, polyurethane, rubber latex, or vinyl plastisol. 

Davies RJ, Eichhom SJ, Riekel C et al (2004) Crystal lattice deformation in single poly (p-phenylene benzobisoxazole) fibres. Polymer 45 7693-7704... 

Description of the lattice fibres and their demarcation by elastic fibre and collagenous connective tissue by A. Oppel. 

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