Differential scanning calorimetry of aqueous polymer solutions and gels

Ahad, Elie

doi:10.1002/app.1974.070180601

Cited by 24 publications

(12 citation statements)

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“…AHAD used the method under consideration to determine the solubility of water in some polymers [17]. AHAD used the method under consideration to determine the solubility of water in some polymers [17].…”

Section: Methods and Resultsmentioning

confidence: 99%

Calorimetric methods and determination results of compatibility of a number of plasticizers with polymers

Rabinovich¹,

Mochalov²,

Tsvetkova³

et al. 1983

Acta Polymerica

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Methods for determining the compatibility of polymers with plasticizers and plotting the diagrams of physical states of their mixtures based on calorimetric data are described. The first method is applicable t o crystallizable plasticizers and the results obtained refer to their melting temperature. I t is based on the determination of the mass of undissolved fraction of plasticizer, introduced in the polymer, by the enthalpy of its melting. The second method is universal, being based on the calculation of the concentration and temperature dependence of Gibbs energy for mixing. The results of the methods and the dependences T, = fin,), dTg/dn2 = fin,) and d2Tg/dnZ2 = f(n2) are presented, where T, is the glass temperature of the mixture, n2 is the plasticizer amount, which were used to study the compatibility of PVC with 9 conimercial plasticizers as well as of cellulose diacetate and nitrocellulose with 6 plasticizers. The relative efficiency of the plasticizers studied is determined. Calorimetrische Methoden und experimentelle Ergebnisse zur Vertraglichkeit einiger Plastifikatoren mit PolymerenMethoden zur Bestimmung der Vertraglichkeit von Polymeren mit Plastifikatoren und zur Konstruktion von Zustandsdiagrammen der Mischungen auf Basis calorimetrischer Messungen werden beschrieben. Die erste Methode ist fur kristallisierbare Plastifikatoren anwendbar, und die erhaltenen Ergebnisse gelten bei der Schmelztemperatur. Sie beruht auf der Bestimmung des ungelosten Anteils des Plastifikators im Polymer aus der Schmelzenthalpie. Die zweite Methode ist universell. Ihre Grundlage ist die Berechnung der Konzentrations-und Temperaturabha4gigkeit der freien Energie des Mischprozesses. Die Loslichkeit wird aus der Konzentrationsabhangigkeit der h d e r u n g des chemischen Potentials des Plastifikators beim Mischen ermittelt. Die mit den Methoden erhaltenen Ergebnisse sowie die AbhangigkeitenT , = f(n,), dTg/dn, = f(n,), und dZTg/dnZ2 = f ( n , ) , wo Tg die Glastemperatur der Mischung und n, der Plastifikatoranteil sind, werden mitgeteilt und auf die Untersuchung der Vertraglichkeit von PVC mit 9 kommerziellen Plastifikatoren sowie von Cellulosediacetat und Nitrocellulose mit 6 Plastifikatoren angewendet. Die relative Wirksamkeit der Plastifikatoren wird bestimmt.

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Section: Methods and Resultsmentioning

confidence: 99%

Calorimetric methods and determination results of compatibility of a number of plasticizers with polymers

Rabinovich¹,

Mochalov²,

Tsvetkova³

et al. 1983

Acta Polymerica

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“…borate, titanate and chromic anions. [53][54][55][56]. Already in 1949, Deuel and Neukom [54] suggested that complexation is the origin of the crosslinks in PVA borate solutions, as shown in Fig.11.…”

Section: Poly(vinyl Alcohol) + Boratementioning

confidence: 96%

On the nature of crosslinks in thermoreversible gels

2006

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SummaryA review is given concerning the nature of crosslinks in thermoreversible gels. In these gels the crosslinks can be formed e.g. by means of crystallisation of parts of polymer molecules, by liquid-liquid phase separation in solution and in bulk, by hydrogen bridging, by complexation of polymer chains, by helix formation, by chemical equilibrium reaction or by interactions between side-chains. One example will be given for each of these eight possibilities of crosslink formation.

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“…In this study, we used the Bloembergen-Morgan equation 18 developed for such a case and obtained eq 2 by calculating the ratio of two (l/T 1 )P values measured at two different NMR frequencies (w 1 , w 2 ). 19 l+w/(~r,/ ( :: )\1 +w1 2 r/) (2) Properly speaking, eq 2 must be applied only to these complexes which have fixed coordination structures of their own, such as hydrated metal ions. Although the coordination structure of the present complexes with PV A is unknown owing to the formation of metal hydroxide-like clusters, eq 2 has been used here in order to estimate 'c for convenience.…”

Section: Measurementsmentioning

confidence: 99%

Structural Investigation of Iron(III) and Copper(II) Complexes with Poly(vinyl alcohol) by NMR Techniques

Mori

Yokoi

Fujise

1995

Polym J

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Structures of the iron(III) and copper(II) complexes with poly(vinyl alcohol) (PV A) have been investigated in full detail by NMR techniques, especially through analysis of nuclear magnetic relaxation processes due to paramagnetic metal ions. As a result, it appears well established that the complexes are of a kind in which iron(III) or copper(II) hydroxide-like clusters are included by PV A chains with hydrophobic backbones toward the inside clusters and with hydrophilic OH groups toward the outside bulk water, meaning that the interaction between the clusters and PV A is of a hydrophobic type. By such an interaction, the complexes have certain definite structures, because there is always a linear relationship between the 1 H NMR signal intensity of PVA and the concentration of metal ion in every system of complex formation. In the case of the PY A of not less than 250 in the degree of polymerization, however, there has also appeared another linear relationship with a more gentle slope over a relatively high concentration range of iron(III), suggesting that such PV A molecules can form both complexes containing only one and two or more clusters.KEY WORDS Poly(vinyl alcohol) / Degree of Polymerization / Iron(III) Complex/ Copper(II) Complex/ Metal Hydroxide-Like Cluster/ 1 H NMR

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Differential scanning calorimetry of aqueous polymer solutions and gels

Cited by 24 publications

References 0 publications

Calorimetric methods and determination results of compatibility of a number of plasticizers with polymers

Calorimetric methods and determination results of compatibility of a number of plasticizers with polymers

On the nature of crosslinks in thermoreversible gels

Structural Investigation of Iron(III) and Copper(II) Complexes with Poly(vinyl alcohol) by NMR Techniques

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