Crystalline Glass

Highest thermal performance with PPS compounds requires that parts be molded under conditions leading to a high level of crystallinity. Glass-filled PPS compounds can be molded so that crystalline or amorphous parts are obtained. Mold temperature influences the crystallinity of PPS parts. Mold temperatures below approximately 93°C produce parts with low crystallinity and those above approximately 135°C produce highly crystalline parts. Mold temperatures between 93 and 135°C yield parts with an intermediate level of crystallinity. Part thickness may also influence the level of crystallinity. Thinner parts are more responsive to mold temperature. Thicker parts may have skin-core effects. When thick parts are molded in a cold mold the skin may not develop much crystallinity. The interior of the part, which remains hot for a longer period of time, may develop higher levels of crystallinity. 

The physical properties (7-10) of our E-V copolymers are sensitive to their microstructures. Both solution (Kerr effect or electrical birefringence) and solid-state (crystallinity, glass-transitions, blend compatibility, etc.) properties depend on the detailed microstructures of E-V copolymers, such as comonomer and stereosequence distribution. I3C NMR analysis (2) of E-V copolymers yields microstructural information up to and including the comonomer triad level. However, properties such as crystallinity depend on E-V microstructure on a scale larger than comonomer triads. 

Although fly ash is largely non-crystalline glass, the major and minor elements in fly ash (O, Si, Al, Fe, Ca, Mg, and S) foim several different phases that have been characterized by XRD in many research projects (Diamond 1984 McCarthy 1988 Bergeson etal. 1988 Thedchanamoorthy McCarthy 1989 Ainsworth et al. 1993). The phases of major elemental constituents that have been commonly identified in fly ash include quartz mullite, Al6Si20 3 tricalcium aluminate, Ca3Al206... 

Table 5.5. Composition, pretreatment, crystallinity, glass transition temperature Tg and experimental and calculated microhardness values, Hg p, and Hgai and their difference AH = Hgai — Hg p for thermoplastic elastomers of PEE-or PEEC-type. 

When drawn into fibers from the melt, these polymers are observed to have two preferred orientations, with the director of one mesophase parallel to the flow direction and that of the other mesophase perpendicular to the flow direction. Also presented are the first linear viscoelastic data of polymers which form liquid crystalline glasses. 

The chain-end functionalized polymer is a very attractive material that possesses an unperturbed polymer chain with desirable physical properties (such as melting temperature, crystallinity, glass transition temperature, melt flow, etc.) that are almost the same as those of the pure polymer. Nevertheless, the terminal reactive group at the polymer chain end has good mobility and can provide a reactive site for many applications. This includes adhesion to the substrates, reactive blending, and formation of block copolymers. 

DSC (solid state) Crystallinity, glass transition A must-have for lyophilized products... 

Appearance Melting temperature (°C) Density (g/cc) Tensile strength [psi (N/m )l Solubility Crystallinity (%) Glass transition temperature (°C) Hard solid 175 0.90-0.92 5,000 (3.4X10 ) Insoluble in most organic solvents <70 0 to —35 Hard solid 131 0.89-0.91 Soluble in ether and aliphatic hydrocarbon Soft rubbery <100 0.86-0.89 Soluble in common organic solvents -11 to -35... 

Similar procedures have been used by several workers (Halasa et al., 1982) to hydrogenate poly(l,4-butadiene-co-1,2-butadiene) diblocks (Halasa, 1985) and poly(l,4-butadiene-co-l,4-isoprene-co-1,4-butadiene) triblocks. Hydrogenation of these diblock and triblock copolymers forms thermoplastic elastomers with crystalline and amorphous segments. All these materials exhibit crystallinity, glass transition, solubility, and dynamic mechanical loss spectra different from those of their unsaturated counterparts. 

Ravenscroft, George developed lead crystal glass during the last quarter of the seventeenth century to rival the Venetian cristallo developed during the early sixteenth century. He was granted a patent in March 1674 for a crystalline glass resembling rock-crystal. ... 

N.S.S. Kumar, S. Abraham, K.V. Ratheesh, N. Tamaoki, S. Purumi, S. Das, Indane-1,3-Dione and cholesterol containing butadiene derivatives photoresponsive liquid crystalline glasses for imaging applications. J. Photochem. Photobiol. A Chem 207, 73-78 (2009)... 

G.S. Attard, C.T. Imrie, F.E. Karasz, Low molar mass liquid-crystalline glasses preparation and properties of the a-(4-cyanobiphenyl-4 -oxy-)-co-(l-pyrenimine-benzylidene-4 -oxy)alkanes. Chem. Mater. 4, 1246-1253 (1992)... 

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