Texture, crystalline

The chemical compositions of the samples were obtained by ICP in a Varian 715-ES ICP-Optical Emission Spectrometer. Powder X-ray diffraction was performed in a Philips X pert diffractometer using monochromatized CuKa. The crystallinity of the zeolites was obtained from the intensity of the most intense reflection at 23° 20 considering the parent HZ5 sample as 100% crystalline. Textural properties were obtained by nitrogen physisorption at -196°C in a Micromeritics ASAP 2000 equipment. Surface areas were calculated by the B.E.T. approach and the micropore volumes were derived from the corresponding /-plots. Prior to the adsorption measurements the samples were degassed at 400°C and vacuum overnight. 

Alloys of Silver.—Silver unites difficultly with iron. Upon fusing silver with that motel, tho alloy separates into silver retaining about one-thirtieth of iron, and iron retaining about onc-cighticth of silver The latter has a peculiar hard and crystalline texture. 

Further evidence in favour of the amorpho-crystalline texture was recently provided by Ranby [46]. In a series of his papers several questions connected with the microstructure of cellulose are made clear. Cellulose to be examined in an electron microscope was initially dispersed by means of ultrasonic waves. In this way Ranby has isolated elementary thread-like micelles of about 70 A dia. Any dimension characterizing the length of the micelle is however missing. 

A newer development is the manufacture of bi-axially oriented bottles, in particular for PETP. The pre-form is injection- moulded and rapidly cooled in the mould it remains amorphous (PETP crystallises very slowly) by heating above its Tg (65°) it passes into the rubbery state, and can then be blown-up and, simultaneously, longitudinally stretched. The biaxial orientation thus obtained, accelerates the crystallisation, and, at the same time, results in a very fine crystalline texture, so that a thin-walled, strong, transparent and heat-resistant bottle is obtained. 

Fig. 8. Liquid-crystalline textures of didodecyl-PPE 12c. Bars represent 20 microns. These PPEs form homeotropic smectic phases the textures are typical for an edge-on view of lamellae that show apparent nematic ordering in this projection [46],...

Lyotropic liquid crystalline properties were observed for poly (arylamide) monodendrons derived from 1,3,5-substituted amino acid chloride hydrochlorides according to Kim [168]. These systems aggregate readily to form high molecular weight species in the absence of complexing ions. Amide solvents containing more than 40 wt.% of the dendrons exhibit nematic phase liquid crystalline texture under a polarizing microscope, whereas, 60 wt.% solutions produce a hard gel under static conditions. 

Two papers published in 1991 described the thermal properties of the diester ferrocene derivatives 8 [15] and 9 [16] (Fig. 9-4). Complexes 8 (n = 3, 4, 6, 8) were found to be non-mesomorphic and 8 (n = 10) seemed to give rise to a smectic phase (unidentified) between 85 °C and 88 °C during the second heating cycle. When 9 n = 1) was cooled from the isotropic melt at a rate of 2 °C/min, a liquid crystalline texture was observed (transition temperatures and liquid crystalline range not given) that, according to the authors, was indicative of a smectic phase. The latter was not identified. Derivative 9 n = 10) formed a nematic phase between 78 °C and 79 °C. This mesophase did not reform on cooling from the isotropic melt. 

Figure 4. Liquid crystalline texture of Ci diphosphate derivative.

The caramels, depending on the type and ratio of the ingredients, may have amorphous or crystalline texture. 

Y. Kawanishi, T. Tamaki, T. Seki, M. Sakuragi, Y. Suzuki, and K. Ichimura, Multifarious liquid crystalline textures formed on a photochromic azobenzene polymer film, Langmuir 7,1314-1315 (1991). 

Table 1.1 Relative dielectric constant en anodic formation factor m, density p, band gap energy Eg, cation transfer coefficient t + f bias dependence and electronic behavior (SC = semiconductor), structure (a = amorphous, c = crystalline), texture dependence for some of the oxide systems described in this treatise (see also [20]). 

The domain structure and crystalline texture of AB and ABA type block copolymers of ethylene oxide (EO) and isoprene (Is) are studied, and the effects of the casting solvents and the fractional compositions of each block segment are determined. The domain structures of EO-Is copolymers are essentially identical to those of EO-Is-EO copolymers, but they strongly depend on the fractional compositions and the casting solvents. The role of casting solvent in the different domain formation mechanisms is interpreted in terms of an interrelation of two binodal surfaces that represent the critical concentration for crystallization of the EO segment and the critical concentration for micelle formation of the incompatible EO and Is segments. 

When one component of an amorphous block copolymer is replaced by a crystalline polymer, the domains or crystalline texture formed by the solvent cast should depend at least on two factors (a) crystallization of the crystalline block segment and (b) microphase separation resulting from the incompatibility of the A and B blocks. The crystalline texture observed in solid film is considered strongly dependent on the relative contributions of the two phase... 

Figure 1. Cross polarized photomicrographs of films of EO-Is-EO block copolymers with relatively large fractions of EO segments revealing less perfect development of spherulitic crystalline texture as the Is content increases...

The domain formation mechanism and structure of these copolymers were similar to those of amorphous AB and ABA type block copolymers of styrene and isoprene when benzene, a nonselective solvent, was used as the casting solvent except that one phase was crystallizable and the domain structures were distorted with resultant irregularities in size, shape, and mutual arrangement of domains. The irregularities are attributable to the development of crystalline texture. This is probably valid also for a selective solvent that is good for the crystallizable EO segment but poor for the noncrystallizable Is segment (see below). 

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