Refractive index increments of polymers in solution: 2. Refractive index increments and light-scattering in polydisperse systems of low molecular weight

The miscibility of starch and poly(ethyleneglycol) (PEG)blends in water were investigated by viscosity, densityand refractive index studies. The physical interactionparameters like poly-solvent and blend-solvent have beencalculated using viscosity and density data. Starch/PEGblends were found to be miscible in all studied ratios. Thestudy also revealed that variation of temperature does notaffect the miscibility of starch and PEG blends in theaqueous solution significantly. The miscibility occurs dueto presence of hydroxyl-hydroxyl interactions in theblends. The result obtained reveals that PEG can beeffectively used as gelating agent in starch solution.Keywords: Miscibility, viscosity, polymer interaction, starch, PEG

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Refractive Index of Natural Rubber for Different Wave Lengths

Rubber Chemistry and Technology ◽

10.5254/1.3547044 ◽

1950 ◽

Vol 23 (3) ◽

pp. 661-669 ◽

Cited By ~ 2

Author(s):

L. A. Wood ◽

L. W. Tilton

Keyword(s):

Molecular Weight ◽

Refractive Index ◽

Natural Rubber ◽

Wave Length ◽

Low Molecular Weight

Abstract The refractive index of natural rubber and its variation with temperature and wave length are those which would be predicted for a similar hydrocarbon of low molecular weight. A two-constant equation of the Cauchy or Sellmeier type is inadequate to express the relation between refractive index and wave length for rubber. For convenient reference the best values resulting from the present investigation are recapitulated in Table VI.

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Aggregation Structure and Electro—Optical Properties of (Liquid Crystalline Polymer)/(Low Molecular Weight Liquid Crystal) Composite System

MRS Proceedings ◽

10.1557/proc-171-305 ◽

1989 ◽

Vol 171 ◽

Cited By ~ 17

Author(s):

Tisato Kajiyama ◽

Hirotsugu Kikuchi ◽

Akira Miyamoto ◽

Satoru Moritomi ◽

Jenn—Chiu Hwang

Keyword(s):

Molecular Weight ◽

Light Scattering ◽

Electric Field ◽

Liquid Crystalline Polymer ◽

Liquid Crystalline ◽

Crystalline Polymer ◽

Smectic Phase ◽

Side Chain ◽

Low Molecular Weight ◽

Smectic Layer

ABSTRACTA series of thin films composed of liquid crystalline polymer (LCP) and low molecular weight liquid crystal (LMWLC) was prepared by a solventcasting method or by a bar—coating method. LCPs were of mesogenic side chain type with strong or weak polar terminalgroups in the side chain portion. A mixture of smectic LCP (LCP with side chain of strong polar end) and nematic LMWLC formed a smectic phase in a LCP weight fraction range above 50 %. Also, a mixture of nematic LCP (LCP with side chain of weak polar end) and nematic LMWLC with strong polar group induced a new smectic phase in a LCP molar fraction range of 20–80 %. Reversible and bistable electro-optical effects based on light scattering were recognized for a smectic phase of a binary composite composed of LCP and LMWLC. A light scattering state caused by many fragmented smectic lamellae appeared in the case of application of an a.c. electric field below a threshold frequency (∼l Hz). Furthermore, application of a 100 Vp—p a.c. field of 1 kHz made the transmission light intensity increased to 94 % within a few seconds. The optical heterogeneity in asmectic layer composed of the side chain group of LCP was caused by the difference of twoforces based on both dielectric anisotropy of the side chain and electrohydrodynamic motion of the main chain. Since application of a low frequency electric field causes an ioniccurrent throughout the mixture film, it is reasonable to consider that an induced turbulent flow of main chains by an ionic current collapsed a fairly well organized large smectic layer into many small fragments, resulting in an increase in light scattering. The response speed of LCP upon application of an electric field increased remarkably by mixingLMWLC. In the case of a smectic mesophase, turbid and transparent states remained unchanged as it was, even though after removing an electric field.1Such abistable and reversiblelight switching driven by two different frequencies of electric field could be newly realized by both characteristics of turbulent effect of a wellorganized large smectic layer of LCP and rapid response of LMWLC. We believe that the LCP/LMWLC mixture system is promissing as a novel type of “light valve” exhibiting memory effect (bistable light switching).

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