Thermal stability of isocyanate-based polymers. 2. Kinetics of the thermal dissociation of model urethane, oxazolidone, and isocyanurate block copolymers

Kordomenos, P. I.; Kresta, J. E.; Frisch, K. C.

doi:10.1021/ma00175a006

Cited by 77 publications

(75 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…(5) is more active at low temperatures than the one formed in eq. (6). The reduction in the activity of the former at high temperatures has a correlation with the behavior of the anionic homopolymerization of epoxides initiated by tertiary amines (a decrease in reaction rate is observed at high temperatures).…”

Section: Reaction Schemementioning

confidence: 89%

Polymer networks based on the diepoxide–diisocyanate reaction catalyzed by tertiary amines

Galante¹,

Williams²

1995

J of Applied Polymer Sci

View full text Add to dashboard Cite

(CONICET), J. B. Justo 4302, (7600) Mar del Plata, Argentina SYNOPSISReactions taking place in a system consisting of a diepoxide (DGEBA, diglycidylether of bisphenol A) and a diisocyanate (TDI 80 : 20, toluene diisocyanate), catalyzed by a tertiary amine (BDMA, benzyldimethylamine), were followed by differential scanning calorimetry (DSC), infrared spectroscopy (FTIR), and chemical titration of isocyanate groups in the pre-gel stage. It was found that the main reactions took place in series, in steps of increasing temperature: (i) isocyanurate formation, (ii) epoxy-isocyanate reaction leading to oxazolidone rings, and (iii) isocyanurate decomposition by epoxy groups producing oxazolidone rings. Isocyanurate rings were stable in the presence of epoxides and a n isocyanate excess [reaction (ii) was faster than (iii)]. Epoxy homopolymerization (secondary reaction) occurred in parallel with steps (ii) and (iii).Step (i) took place by two different mechanisms and led to a maximum conversion, possibly limited by topological restrictions. A kinetic study of TDI trimerization in the presence of an equimolar amount of DGEBA and variable amounts of BDMA led to a third-order regression with an activation energy E = 43 kJ/mol. 0 1995

show abstract

Section: Reaction Schemementioning

confidence: 89%

Polymer networks based on the diepoxide–diisocyanate reaction catalyzed by tertiary amines

Galante¹,

Williams²

1995

J of Applied Polymer Sci

View full text Add to dashboard Cite

show abstract

“…The major drawback of MCPU coatings is the formation of side products on storage and if these reactions are significant, both pot stability and shelf life are expected to be dramatically affected. The presence of side products, for example allophanate and isocyanurate, add branch points, which increases the viscosity of the NCO capped prepolymer and changes the onset of gelation during cure and thereby lower the storage stability of the product [4][5][6][7]. The presence of additional hard segment material due to biuret and allophanate changes the hard domain volume fraction and hence the interconnectivity of the hard segments [8], alter the thermal properties [9,10] as well as adhesive behaviour [11].…”

Section: Introductionmentioning

confidence: 99%

The phase mixing studies on moisture cured polyurethane-ureas during cure

Chattopadhyay

Sreedhar

Raju

2006

Polymer

View full text Add to dashboard Cite

“…The literature on this subject predominantly describes the thermal decomposition of various polyurethane samples under pyrolytic conditions of decomposition (thermogravimetry). [3][4][5][6][7][8] According to a velocity law, logically consistent first-order kinetics are confirmed for the pyrolytic thermal decomposition. Theoretically, however, a chain cleaving and a recombination of reactive end groups can take place.…”

Section: Introductionmentioning

confidence: 74%

The Kinetics of the Thermal Decomposition of Thermoplastic Polyurethane Elastomers under Thermoplastic Processing Conditions

Endres

Lechner

Steinberger³

2003

Macro Materials & Eng

View full text Add to dashboard Cite

A theoretical approach to the kinetics of the thermal decomposition of molten thermoplastic polyurethane elastomers, under conditions of thermoplastic processing, is described. On the basis of these considerations, the thermal decomposition in different instruments (melt index analyser and measuring extruder) can be described quantitatively and the various results can be compared. As a result, identical conditions of decomposition of the melt can be defined accurately, thus opening up the possibility of combining experimental values from different instruments. The fundamental kinetic equation obtained for the kinetics of the thermal decomposition of thermoplastic polyurethanes describes the decomposition reaction and the reverse reaction (formation reaction) – which is dependent on the system of measurement and processing – as a function of the molar mass (end‐group concentration) of the original product, determined from the velocity constants for the decomposition reaction and back reaction. The consideration of the limiting value for t → ∞ is in agreement with the equilibrium constant. Consequently, the development of physical characteristic functions of thermoplastic polyurethane elastomers – independent of the system of measurement – is possible.Experimental values and calculated curves for the thermal decomposition of PUR‐Et in a melt index analyser.magnified imageExperimental values and calculated curves for the thermal decomposition of PUR‐Et in a melt index analyser.

show abstract

Thermal stability of isocyanate-based polymers. 2. Kinetics of the thermal dissociation of model urethane, oxazolidone, and isocyanurate block copolymers

Cited by 77 publications

References 5 publications

Polymer networks based on the diepoxide–diisocyanate reaction catalyzed by tertiary amines

Polymer networks based on the diepoxide–diisocyanate reaction catalyzed by tertiary amines

The phase mixing studies on moisture cured polyurethane-ureas during cure

The Kinetics of the Thermal Decomposition of Thermoplastic Polyurethane Elastomers under Thermoplastic Processing Conditions

Contact Info

Product

Resources

About