Search results for " crystalline"

Microphthalmia, persistent hyperplastic hyaloid vasculature and lens anomalies following overexpression of VEGF-A188 from the αA-crystallin promoter

2007

Purpose During growth of the embryonic eye, dose- and site-specific expression of heparin-binding growth factors is critical for the formation of an appropriate vascular supply. Overexpression of vascular endothelial growth factor-A188 (VEGF-A188), a strongly heparin-binding, endothelial-specific mitogen, leads to severe disturbance of vascular and overall ocular morphology. This study aimed to evaluate the effects of VEGF-A188 overexpression on growth of ocular tissue components. Methods Stereological and immunohistochemical methods were employed to identify the vascular profiles, ocular tissue proportions, and cell types in VEGF-A188 transgenic mice and compare them with wild-type mice. R…

Liquid-crystalline ionomers

1997

Liquid-crystalline (LC) ionomers combine the properties of ionomers (cluster formation of the ionic groups) with LC phases. They can be prepared with LC main-chain and LC side-chain polymers.

High resolution electron microscopy of liquid crystalline polymers

1990

Les images de microscopie electronique a haute resolution des polymeres cristaux liquides calamitiques [CO−CH(R)−CO 2 −(CH 2 ) 6 −OPh−N:N−PhO−(CH 2 ) 6 −O] n (R=CH 2 −CH=CH 2 , (CH 2 ) 6 −O−Ph N=N−Ph−CN) et discotique poly (hexadecanedioate de triphenylene) sont simulees sur ordinateur et comparees avec les structures obtenues a partir des resultats experimentaux de diffraction electronique. Une theorie est developpee pour expliquer le bon accord observe

1985

Etude des phases isotrope, nematique et smectique de melanges de polymeres protones et en partie deuteries

1978

Deuteron NMR Relaxation Studies of Combined Main-Chain/Side-Chain Polymers in the Liquid Crystalline and Glassy State

1989

Etude du polymere [O−Ph−CO 2 −Ph(R)−O−CO−Ph−O-(CH 2 ) 10 −] n (R=(CH 2 ) 6 −O−Ph−N=N−Ph−OMe) qui est caracterise par des parametres d'ordre des mesogenes de la chaine principale tres superieurs a ceux des chaines laterales. On observe une biaxialite moleculaire dans toutes les mesophases et dans la phase smectique A

Characterization of a fiber-reinforced new fully aromatic liquid crystalline polymer

1998

A new rigid liquid crystalline polymer that demonstrates good mechanical and thermomechanical properties and acceptable processing temperature has been recently synthesized and characterized. The melting temperature and some thermomechanical properties do not seem, however, suitable for use in some applications at high temperature or in the presence of aggressive fluids. The use of appropriate inorganic fillers can overcome these shortcomings. In this work the new LCP, polymerized in a bench-scale apparatus, and the same sample filled with carbon fibers are characterized. The properties of the carbon fiber filled LCP are compared with those of another filled wholly aromatic commercial LCP,…

Halogen-bonded photoresponsive materials

2015

The aim of the present review is to illustrate to the reader the state of the art on the construction of supramolecular azobenzene-containing materials formed by halogen bonding. These materials include several examples of polymeric, liquid crystalline or crystalline species whose performances are either superior to the corresponding performances of their hydrogen-bonded analogues or simply distinctive of the halogen-bonded species. submittedVersion Peer reviewed

Synthesis and Characterization of a New Fully Aromatic LCP

1996

Abstract Liquid crystal polymers (LCP)are a relatively new class of polymers with very interesting and unusual properties. In particular, easy processability and outstanding mechanical and barrier properties make them very attractive. Unfortunately the high stiffness of their chains often leads to compounds having very high melting points and consequently to unprocessable materials. By adding a flexible segments in the chain backbone the LCPs become processable at lower temperatures but lower properties are displayed. A new rigid liquid crystalline polymer, having excellent physical properties, good processing temperature and a good cost/performance compromise, is described in this work. Th…

1979