Crystalline polar additives

Modification of Ionic Associations by Crystalline Polar Additives... 

This paper attempts to further explore the modification of ionic associations by a crystalline ionic plasticizer, such as zinc stearate, at the solid state. Mechanical properties, swelling behavior, and morphological aspects were studied in order to better understand the role of such crystalline polar additives. 

From the various data reviewed and presented here, it is evident that a crystalline polar additive such as zinc stearate acts as... 

Diazaphospholes 4 and 5 are colorless to pale yellow distillable liquids or crystalline solids that are stable to oxidation by air and do not react with elemental sulfur. They are readily hydrolyzed to give the hydrazone from which they originate and phosphorus acid. While only a few reactions of 1/7-1,2,3-diazaphospholes 4 are reported, the chemistry of the 2//-isomers 5 is well studied. In CHEC-II(1996), the following reactions of 1,2,3-diazaphos-pholes are described in detail N-protonation and alkylation, polar addition to the P=C bond and substitution at C-4, cycloaddition reactions, substituent reactions, and the formation of transition metal complexes <1996CHEC-II(4)771>. 

Duvdevani(40) have been directed at modification of ionomer properties by employing polar additives to specifically interact or plasticize the ionic interactions. This plasticization process is necessary to achieve the processability of thermoplastic elastomers based on S-EPDM. Crystalline polar plasticizers such as zinc stearate can markedly affect ionic associations in S-EPDM. For example, low levels of metal stearate can enhance the melt flow of S-EPDM at elevated temperatures and yet improve the tensile properties of this ionomer at ambient temperatures. Above its crystalline melting point, ca. 120°C, zinc stearate is effective at solvating the ionic groups, thus lowering the melt viscosity of the ionomer. At ambient temperatures the crystalline additive acts as a reinforcing filler. 

None of the complexes with three and four chiral chains was liquid crystalline. In addition, the number and position of these chains drastically influenced the ferroelectric properties, particularly spontaneous polarization, as well as the... 

Small amounts of chlorine produce irregularities in the polymer structure. This reduces crystallinity and hence lowers the softening point. Large amounts of chlorine in the structure lead to resumed crystallinity in addition to higher polarity. Thus the softening point increases. 

In summary, the effect of secondary dopants in PEEXDTiPSS on the molecular level appears in some ways to be similar to that of m-cresol in polyaniline. In both cases the plasticizer effect of a very polar additive with low volatility induces reorganization. In the case of PEDOTiPSS no crystallinity is found— possibly due to the polymeric nature of the counterion—but still an ordering effect can be shown. In both cases, the organization on the nanometer scale leads to a macroscopic conductivity increase. 

The process yields a random, completely soluble polymer that shows no evidence of crystallinity of the polyethylene type down to —60°C. The polymer backbone is fully saturated, making it highly resistant to ozone attack even in the absence of antiozonant additives. The fluid resistance and low temperature properties of ethylene—acryUc elastomers are largely a function of the methyl acrylate to ethylene ratio. At higher methyl acrylate levels, the increased polarity augments resistance to hydrocarbon oils. However, the decreased chain mobiUty associated with this change results in less fiexibihty at low temperatures. 

The density of the polymer will clearly depend on the density of the soft phase (usually low), and the density of the hard phase (generally higher with crystallisable polar blocks) and the ratio of the soft and hard phases present. It will also clearly depend on the additives present and to some extent on the processing conditions, which may affect the crystalline morphology. 

We set out with the idea that, in the vicinity of each ion in solution there is likely to be a certain amount of electrostriction—a certain shrinkage of the solvent caused by the attraction between the ionic charge and the polar molecules. In order to estimate from experimental data how much shrinkage, if any, has taken place, we must start with a correct idea of what would have been the volume of the solution, if no shrinkage had taken place. In making a comparative study of various solutes, we need a common basis for comparison. Since this is not provided by the volumes of the crystalline solids, we may try a different approach. We may compare the addition of any pair of ions to the solvent with the addition of a pair of solvent molecules. 

In addition, some liquid-crystalline elastomers are ferroelectric (possess spontaneous electric polarization) [196,197], or piezoelectric (become electrically... 

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