Conventional crystalline

A concept gaining support is a hybrid approach to making thick crystalline silicon efficient in thin layers. Although conventional crystalline silicon cells have gone from 400—600-p.m thick to 200—300-p.m, thin-film crystalline silicon cells have reached 10% efficiency while being only 10-p.m thick. 

The commercial appearance of phenolic resins fibres in 1969 is, at first consideration, one of the more unlikelier developments in polymer technology. By their very nature the phenolic resins are amorphous whilst the capability of crystallisation is commonly taken as a prerequisite of an organic polymer. Crystallisability is not, however, essential with all fibres. Glass fibre, carbon fibre and even polyacrylonitrile fibres do not show conventional crystallinity. Strength is obtained via other mechanisms. In the case of phenolic resins it is obtained by cross-linking. 

Figure 25.24. Difference in behaviour between liquid crystal polymers and conventional crystalline polymers in the melt at rest, during shear and when cooled after shearing...

Laser and electron beam processing are effective methods for preparing amorphous surface alloys covering conventional crystalline bulk metals... 

The nylons used as modifiers for epoxy adhesives are soluble, semicrystalline copolymers made from conventional nylon monomers.7 These resins can be dissolved in alcohols and other solvents, and they can be melted below their decomposition temperature. A preferred solvent mixture is ethanol plus up to 20% water. A commercial example of an adhesive-grade nylon is Dupont s Zytel 61. Conventional crystalline nylon polymers, such as nylon 6 or nylon 66, would be incompatible with epoxy resins. 

One of the characteristic of the nascent powder structure is the presence of an intermediate phase included with conventional crystalline and amorphous phases. The higher ductility of polyethylene nascent powders suggested the coexistence of less entangled amorphous phases located between crystalline and amorphous phases.24 4 46 This arises from the non-equilibrium crystallisation during polymerisation. Therefore, the polymerisation temperature affects the structure and the morphology of the nascent powder. 

It has long been known that highly crystalline forms of polybutadiene with melting points higher than conventional crystalline polybutadiene are available via radiation polymerization of thiourea inclusion compounds (1. Crystallographic studies of the polymerization of butadiene derivatives in inclusion complexes have been reported (53). Recently, butadiene derivatives in layer perovskite salts have been polymerized to singlecrystal polymers which have been structurally characterized (54). 

Cellulose fiber contains both crystalline and amorphous regions. X-ray diffraction (XRD) diagrams give discernable patterns that indicate the existence of a crystalline arrangement of the molecules in the cellulose fiber. On the other hand, the spots on the XRD diagrams aie somewhat blurred and not as clearly defined as those from conventional crystalline substrates. 

Studies of X-ray diffraction patterns, specific volume, and mechanical properties of PBLG films led us to intuit that some of these solid films cast from certain solvents such as chloroform and methylene chloride retained the local structure of the liquid crystalline phase. On the other hand, conventionally crystalline films of PBLG were obtained from the solvent dimethyl formamide. ... 

Quasicrystal - A solid having conventional crystalline properties but whose lattice does not display translational periodicity. 

It is generally accepted that conventional crystalline microporous solids are based on frameworks formed by linked TO4 tetrahedra, each oxygen being shared between two T elements and with Si, (Si, Al) or (Al, P) as the main T elements. Materials are non-conventional if they correspond to solids with novel structures, with novel composition and/or prepared by new synthesis routes (implying generally new characteristics of the solids obtained). 

On the basis of this model it was anticipated ( ) that a syndiotactic configuration of the macromolecules would have favored the attainment of a higher degree of order and perhaps also the formation of conventional crystalline structures. Studies have therefore been undertaken in order to synthesize samples of PPBA having different types of stereoregularity and to determine their morphology and physical properties. 

When Armand [16, 17] presented the results of his original studies on PEO-based polymer electrolytes, he was influenced by knowledge of the conduction processes in conventional, crystalline electrolytes and therefore envisaged transport within the ionically conducting polymer as taking place in the crystalline regions. This seemed implausible to polymer chemists and Berthier [19] was soon able to show by solid state NMR studies that ionic transport in fact occurred within the amorphous regions. 

Disordered alloys of this kind can have high strength and corrosion resistance, and extreme hardness and wear resistance, and compare favourably with conventional crystalline metal alloys. Some amorphous alloys have unique magnetic properties with low coerdvity, low hysteresis loss and high permeability. 

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