Poly crystallinity

Table 6. Properties of Crystalline Poly(4-Methyl-l-Pentene) ...

Table 3. Glass-Transition Temperature of Amorphous Poly(Vinyl Ether)s and Melting Points of Crystalline Poly(Vinyl Ether)s ...

X-ray diffraction analysis of crystalline poly(schiff base)s and their low molecular models shows that the formation of molecular complexes is accompanied by an increase in interplanar distances and, in a number of cases, by complete amor-phization. Molecular complexes of poly(schiff base)s with Br2 decompose with time, because of the bromination of the donor components, forming C—Br bonds. Substitution of hydrogen by bromine in phenyl groups occurs only in cases in which these groups are not included into the main polymeric chain. 

None of the early systems have enjoyed significant clinical success (67). This is most probably due to two factors. Most of the formulations were based on crystalline poly(L-lactide) rather than the... 

Fig. 1.—Schematic representation of polymer chains in crystalline poly-(hexamethylene adipamide). Layer structure resulting from association of polar groups is indicated by transverse parallel lines. (From Baker and Fuller, J. Am.

The head-to-tail arrangement in poly-(vinyl alcohol) is further confirmed by its X-ray diffraction pattern in the crystalline state. Likewise, analysis of the X-ray diffraction of crystalline poly-(vinylidene chloride), (—CH2—CCI2—)x, and of crystalline (stretched) polyisobutylene, [—CH2—C(CH3)2—]x, shows the units to be arranged in these cases also in the expected head-to-tail forms. 

J Oguma, K Akagi, and H Shirakawa, Synthesis and properties of liquid crystalline poly(p-phenylene) and poly(/j-phcnylcnc vinylene) derivatives, Synth. Met., 101 86-87, 1999. 

Structurally PVC molecule is partially syndioactic and so it has low crystallinity. Poly (vinyl chloride) is, having ahead-to-tail structure ... 

Boulanger, P., Pireaux, J. J., Verbist, J. J. and Delhalle, J., XPS study of polymer chain conformation in amorphous and crystalline poly(ethylene terephthalate) samples, J. Electron Spectrosc. Rel. Phenom., 63, 53-73 (1993). 

Fontaine, F., Ledent, J., Groeninckx, G. and Reynaers, H Morphology and melting behaviour of semi-crystalline poly(ethylene terephthalate) 3. Quantification of crystal perfection and crystallinity, Polymer, 23,185-191 (1982). 

Fig. 5.2 The structure of crystalline poly(ethylene oxide) showing the contents of one unit cell.

In light of the above discussion, it is of interest to Investigate sulfonated Bis A-PSF more fully than has been previously reported. Bis A-PSF of different molecular weights and the entire range of D.S. (from 0.0 to 1.0) with a variety of counter-ions can be Investigated. Through the use of castable, but partially crystalline poly(arylene sulfones) such as... 

The chain conformation of crystalline poly(l,l-difluoroethene), modification 2, is ... 

Imperial Chemical Industries has introduced a new crystalline poly(ether ether ketone) (PEEK) (structure 4.78). Applications are for compressor plates, valve seats, thrust washers, bearing cages, and pump impellers. In the aerospace industry it is employed as aircraft fairing, fuel valves, and ducting. It is also used in the electrical industry as wire coating and semiconductor wafer carriers. 

Sant Angelo JG (1996) Substantially crystalline poly(alkylene carbonates) laminate and methods of making. US Patent 5,536,806... 

Fig. 1.9. Dependence of elastic modulus on temperature in amorphous (—) and in crystalline (—) poly(ethylene terephthalate)...

The ideal systems to test this conjecture are single-crystalline poly-diacetylenes (PDAs), notably perfect PDA chains embedded in a crystalline lattice [15]. Employing the electroreflection method, Weiser and Mbller [136] analyzed the... 

Fig. 3 Chemoenzymatic routes to crosslinked macrolactones. Left enzymatic polymerization of a-methylenemacrolides and subsequent vinyl polymerization [10]. Right Enzymatically synthesized highly crystalline poly(ambrettolide) before and after thermal crosslinking [11]...

These hydrophobic crystallites fit properly into a planar bilayer by formation of H-bonds between the free end groups of the oligomers and the polar head groups of the phospholipids. In other words, a membrane contains islands of crystalline poly(3-HB) within the liquid crystalline phospholipid phase. A schematic representation is shown in Figure 8. Single-channel current fluctuations are assumed to... 

In EVA polymers the glass transition temperature of the polymer can be controlled by adjusting the ethylene content. As more ethylene is present in the polymer as lower is the glass transition temperature. However, under certain conditions of polymerization the formation of crystalline poly(ethylene) domains are favored. 

Kennedy and Thomas (1) first reported the synthesis of a crystalline poly(3-methyl- 1-butene) by cationic polymerization at —130°C. Preliminary HNMR studies indicated that the polymer was not simply a tactic modification of the conventional 1,2-polymer but, in fact, possessed a repeat structure which resulted... 

Fig. 8.300 MHz PMR spectrum of crystalline poly(3-methyl-l-butene) (A1C13, EtCl, —130° C)...

Only in the case of highly crystalline poly-(S)-3-methyl-l-pentene there is a remarkable discrepancy between the rotatory power found by Pino and co-workers (775) [a f = -j-194 (in decalin) and by Mtjrahashi and co-workers (90)... 

Fig. 7. Double logarithmic Avrami plots for the crystallization of liquid crystalline poly(oxy-2 -dimethylazoxybenzene-4,4 -diyloxydodecanedioyl) to the fully ordered state between 322 and 362 K. Average of the Avrami exponent 3.5 0.3. Diagram courtesy J. Wiley and Sons27 ...

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