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Phase diagrams of smart copolymers poly(N-isopropylacrylamide) and poly(sodium acrylate).

Zarzyka I, Di Lorenzo ML, Pyda M - ScientificWorldJournal (2014)

Bottom Line: Experiments related to linear polymers (PNIPA and PNIPA-SA) indicated nontypical demixing/mixing behavior with a lower critical solution temperature (LCST), which do not correspond to the three classical types of limiting critical behavior.Some similarities and differences are observed in comparison to our literature data using standard TM-DSC for PNIPA/water.Furthermore no influence of composition cross-linked PNIPA/water system on demixing/mixing temperature was observed.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Rzeszow University of Technology, 35-959 Rzeszow, Poland.

ABSTRACT
The phase behavior of linear poly(N-isopropylacrylamide) (PNIPA), linear copolymer poly(N-isopropylacrylamide) and poly(sodium acrylate) (PNIPA-SA), and chemically cross-linked PNIPA in water has been determined by temperature modulated differential scanning calorimetry (TM-DSC). Experiments related to linear polymers (PNIPA and PNIPA-SA) indicated nontypical demixing/mixing behavior with a lower critical solution temperature (LCST), which do not correspond to the three classical types of limiting critical behavior. Some similarities and differences are observed in comparison to our literature data using standard TM-DSC for PNIPA/water. Furthermore no influence of composition cross-linked PNIPA/water system on demixing/mixing temperature was observed.

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TM-DSC thermograms of PNIPA-SA/water (40%/60%) system in equilibrium swelling degree, upon heating rate of (a) 1 K/min and (b) 5 K/min and cooling rate of 10 K/min.
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fig3: TM-DSC thermograms of PNIPA-SA/water (40%/60%) system in equilibrium swelling degree, upon heating rate of (a) 1 K/min and (b) 5 K/min and cooling rate of 10 K/min.

Mentions: Due to the fact that this work was mostly qualitative analysis of phase separation of PNIPA and its comonomers/water systems, all measurements were performed at 5 K/min heating rate. This heating rate was selected based on the further preliminary investigations which showed the most convenient heating rate to such type of analysis (Figure 3).


Phase diagrams of smart copolymers poly(N-isopropylacrylamide) and poly(sodium acrylate).

Zarzyka I, Di Lorenzo ML, Pyda M - ScientificWorldJournal (2014)

TM-DSC thermograms of PNIPA-SA/water (40%/60%) system in equilibrium swelling degree, upon heating rate of (a) 1 K/min and (b) 5 K/min and cooling rate of 10 K/min.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4150473&req=5

fig3: TM-DSC thermograms of PNIPA-SA/water (40%/60%) system in equilibrium swelling degree, upon heating rate of (a) 1 K/min and (b) 5 K/min and cooling rate of 10 K/min.
Mentions: Due to the fact that this work was mostly qualitative analysis of phase separation of PNIPA and its comonomers/water systems, all measurements were performed at 5 K/min heating rate. This heating rate was selected based on the further preliminary investigations which showed the most convenient heating rate to such type of analysis (Figure 3).

Bottom Line: Experiments related to linear polymers (PNIPA and PNIPA-SA) indicated nontypical demixing/mixing behavior with a lower critical solution temperature (LCST), which do not correspond to the three classical types of limiting critical behavior.Some similarities and differences are observed in comparison to our literature data using standard TM-DSC for PNIPA/water.Furthermore no influence of composition cross-linked PNIPA/water system on demixing/mixing temperature was observed.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Rzeszow University of Technology, 35-959 Rzeszow, Poland.

ABSTRACT
The phase behavior of linear poly(N-isopropylacrylamide) (PNIPA), linear copolymer poly(N-isopropylacrylamide) and poly(sodium acrylate) (PNIPA-SA), and chemically cross-linked PNIPA in water has been determined by temperature modulated differential scanning calorimetry (TM-DSC). Experiments related to linear polymers (PNIPA and PNIPA-SA) indicated nontypical demixing/mixing behavior with a lower critical solution temperature (LCST), which do not correspond to the three classical types of limiting critical behavior. Some similarities and differences are observed in comparison to our literature data using standard TM-DSC for PNIPA/water. Furthermore no influence of composition cross-linked PNIPA/water system on demixing/mixing temperature was observed.

Show MeSH
Related in: MedlinePlus