Poly temperature effects

Lochmiiller, C. H., Moebus, M. A., Liu, Q., and Jiang, C., Temperature effect on retention and separation of poly(ethylene glycoljs in reversed-phase liquid chromatography, /. Chromatogr. Sci., 34, 69, 1996. 

Temperature Effect. Near the boiling point of water, the solubility—temperature relationship undeigoes an abmpt inversion. Over a narrow temperature range, solutions become cloudy and the polymer precipitates the polymer cannot dissolve in water above this precipitation temperature. In Figure 4, this limit or cloud point is shown as a function of polymer concentration for poly(ethylene oxide) of 2 x 106 molecular weight. 

A major disadvantage of the HLB concept is that it makes no allowance for temperature effects. With increasing temperature, the hydration of lyophilic (particularly poly(ethylene oxide)) groups decreases and the emulsifying agent becomes less hydrophilic - i.e. its HLB decreases. 

Initiation of Poly merization of Vinyl Monomers Propagation Reactions Termination and Transfer Processes Kinetics of Cationic Polymerization of Olefins Temperature Effects... 

The fluorescence intensity of quinoline derivatives has been found to increase dramatically with an increase in the molecular weight of the host polystyrene. " This is attributed to a decrease in the free volume in the polymer matrix restricting molecular rotation/motion of the fluorophore. Similar effects have been observed for juliodinemalononitrUe in different stereo-regular poly(methyl methacrylates), and temperature effects on the luminescence properties of indole and coumaric acid derivatives in different polymer matrices showed abrupt changes in emission intensity at temperatures which correspond to the onset of local relaxation processes in the polymer. ... 

Here we report preliminary results on the multiple fluorescence emission of 1 and 2. From structure-property relationships, solvent effect and temperature effect studies, we are able to show that the multiple emission is from the emission of free squaraine in solution, the emission of the solute-solvent complex and the emission of a twisted relaxed excited state. Further solvent effect study using 2 as a model shows that squaraine forms strong solute-solvent complexes with alcoholic solvent molecules. Analogous complex-ation process is also detected between 1 and the hydroxy groups on the macromolecular chains of poly(vinyl formal). The Important role of this complexation process on the stabilization mechanism of particles of 1 in polymer solution is discussed. 

J. S. Vrentas and J. L. Duda, Solvent aad Temperature Effects ou Diffusion in Poly me insolvent... 

Bertinelli, E, P. Costa-Bizzarri, C. Della-Casa, and M. Lanzi. 2001. Solvent and temperature effects on the chromic behaviour of poly[3-(10-hydroxydecyl)-2,5-thienylene]. Synth Met 122... 

Sato O, Aral K, Shirai M. Hydrolysis of poly (ethylene terephthalate) and poly(ethylene 2,6-naphthalene dicarboxylate) using water at high temperature Effect of proton on low ethylene glycol yield. Catal Today 2006 111 297-301. 

While the effect of the potential-induced relaxation phenomena has been extensively studied, fewer efforts have been made concerning the temperature effect. A notable exception is a temperature shock experiment on poly(tetracyanoquinodimethane) electrode. It was found that when the electrode returned from an elevated temperature to room temperature, a relatively long time (>30 minutes) was needed to restore the original voltammetric response characteristic for room temperature as seen in Fig. 10. Apparently, the polymer adopts an extended, perhaps solvent, swollen... 

Table 10 summarizes some further results on the reaction of poly(NPMAm) radicals with MMA. Longer reaction times led to an increase in the MMA conversion. The temperature effect on the MMA conversion was, however, not substantial in the range 10 °C to 40 °C. The enhanced propagation with increased temperature may be compensated by an accelerated termination reaction between the polymer radicals. 

J. J. Cooper-White, M. E. Mackay, Rheological properties of poly(lactides). Effect of molecular weight and temperature on the viscoelasticity of poly(l-lactic acid). J. Polym. Sci. Part B... 

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