A Simple Method for Determining the Lower Critical Solution Temperature of Polymer Blends Using a Raman Spectrometer

Coleman, M. M.; Skrovanek, Daniel J.; Painter, Paul C.

doi:10.1366/0003702844555647

Cited by 9 publications

(5 citation statements)

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“…For explanatory purposes, we will present our thermal analysis results first, and then those obtained from light scattering and infrared studies. Cloud point determinations of the P2VP-nylon blends were obtained using a method previously described (8). The results are summarized in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Samples for infrared and thermal analysis were prepared by casting films onto potassium bromide (KBr) windows and aluminum pans, respectively. For the light scattering studies, samples were prepared from solution in small glass vials (8). After evaporation of the majority of the solvent at room temperature, the samples were placed under vacuum in a n oven at 100°C to eliminate residual solvent and water.…”

Section: Methodsmentioning

confidence: 99%

“…The glass transition temperature (Tg) was taken as the midpoint of the heat capacity change. The technique used for the determination of the lower critical solution temperature (LCST) of the blends using a Raman spectrometer has been described previously (8).…”

Section: Methodsmentioning

confidence: 99%

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A miscible nylon blend with poly(2‐vinyl pyridine)

Skrovanek

Coleman

1987

Polymer Engineering & Sci

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Polymer blends of an amorphous polyamide with poly(2vinyl pyridine) (P2VP) are presented. Differential scanning calorimetry results suggest that the system exists as a single phase material as evidenced by a single glass transition temperature. However, as illustrated by light scattering studies, this miscible binary mixture possesses a relatively low, lower critical solution temperature (LCST). Fourier transform infrared (FTIR) spectroscopic investigations indicate that the interactions occur in the blend between the NH group of the polyamide and the N: atom of P2VP and that the strength of the Interactions between the components is nearly identical to that occurring in the self‐association of the pure amorphous polyamide. Additionally, by monitoring the concentration of “free” carbonyl groups, a quantitative measure of the number of interactions occurring in the blend is obtained.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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A miscible nylon blend with poly(2‐vinyl pyridine)

Skrovanek

Coleman

1987

Polymer Engineering & Sci

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“…The LCST can be determined by various analytical methods like optical techniques (e.g., UV-Vis spectroscopy [20–22], dynamic and static light scattering [22–27], infrared spectroscopy [28–31], Raman spectroscopy [32], fluorescence spectroscopy [33]), differential scanning calorimetry [34], or viscometry [35]. However, many of these approaches are usually limited to rather dilute suspensions, exhibiting only single light scattering.…”

Section: Introductionmentioning

confidence: 99%

Process analytical approaches for the coil-to-globule transition of poly(N-isopropylacrylamide) in a concentrated aqueous suspension

et al. 2016

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The coil-to-globule transition of poly(N-isopropylacrylamide) (PNIPAM) microgel particles suspended in water has been investigated in situ as a function of heating and cooling rate with four optical process analytical technologies (PAT), sensitive to structural changes of the polymer. Photon Density Wave (PDW) spectroscopy, Focused Beam Reflectance Measurements (FBRM), turbidity measurements, and Particle Vision Microscope (PVM) measurements are found to be powerful tools for the monitoring of the temperature-dependent transition of such thermo-responsive polymers. These in-line technologies allow for monitoring of either the reduced scattering coefficient and the absorption coefficient, the chord length distribution, the reflected intensities, or the relative backscatter index via in-process imaging, respectively. Varying heating and cooling rates result in rate-dependent lower critical solution temperatures (LCST), with different impact of cooling and heating. Particularly, the data obtained by PDW spectroscopy can be used to estimate the thermodynamic transition temperature of PNIPAM for infinitesimal heating or cooling rates. In addition, an inverse hysteresis and a reversible building of micrometer-sized agglomerates are observed for the PNIPAM transition process.Electronic supplementary materialThe online version of this article (doi:10.1007/s00216-016-0050-7) contains supplementary material, which is available to authorized users.

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“…Other Raman studies that have produced useful information relate to the degradation of poly(vinyl chloride) (199)(200)(201)(202), chain deformations in polypropylene (203,204), studies on polysilanes (205), urea-formaldehyde resins (206), and other composites (207), and methods of determining critical solution temperatures (208), the effects of different draw ratios at different temperatures for polyethylene (209), and rates of conversion from monomer to polymer for styrene and methyl methacrylate (210).…”

Section: Polymersmentioning

confidence: 99%