Structure, equilibrium and viscoelastic mechanical behaviour of polyurethane networks based on triisocyanate and poly(oxypropylene)diols

Ilavský, M.; Šomvársky, Ján; Bouchal, K.; Dušek, Karel

doi:10.1016/0966-7822(93)90009-7

Cited by 17 publications

(10 citation statements)

References 16 publications

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“…This combination predicts an upward curvature of the G(r) plot, which is found in accordance with experimental results obtained on different systems by Ilavsý et al [4], for instance, with triisocyanate and diols. In this comparison, it should be kept in mind that r is defined as [OH]/[NCO] in the latter paper, and that log scales are used in G plots.…”

Section: Discussionsupporting

confidence: 79%

“…In this comparison, it should be kept in mind that r is defined as [OH]/[NCO] in the latter paper, and that log scales are used in G plots. Nevertheless, the linear decreasing trend obtained in Figure 3 of [4], for instance, can be interpreted immediately as an upwardly curved G(r) plot with our notations. In contrast, our experimental results are consistent with observations made by Burel et al [18] on a similar system.…”

Section: Discussionmentioning

confidence: 99%

“…obtained by merely considering the factors of z 3 and z 4 in F 0I (z). This provides the average functionality of active nodes f = (3n 3 + 4n 4 )/(n 3 + n 4 ) and the number of elastically active chains per mole of initial mixture (3n 3 + 4n 4 )/2.…”

Section: Network Formationmentioning

confidence: 99%

“…Both approaches can lead to the same results but, although the latter "can be readily understood and applied by the typical polymer chemist" as stated by its promoters [16], the former approach has been preferred in this paper because its systematic step-by-step unfolding allows easy extensions to systems with components of various functionalities. More specifically, we refer to the work of Dusek and his coworkers ( [1][2][3][4], for instance). Our derivation given below is slightly more direct than what can be found in the literature for other systems, and connections with some previous results are, therefore, given.…”

Section: Network Formationmentioning

confidence: 99%

“…Polyurethane elastomers are good candidates for such studies, they offer a variety of possible systems and have been widely used, as mentioned in [1], for instance. To cite a few among many examples, triols and diisocyanate were used in [2], mono-, bi-, and trifunctional polyols were reacted with diisocyanate in [3], whereas diols and triisocyanate were considered in [4]. In this paper, networks were prepared from two types of diols reacted with a mixture of triisocyanate and quadriisocyanate, for various molar ratios of NCO and OH groups, with an excess of the latter.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

An experimental and analytical study of the elasticity of model polyurethane networks crosslinked by tri- and quadriisocyanate

2009

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. Abstract Polyurethane networks have been prepared from a mix of tri-and quadriisocyanate and from two types of diols, polyether-based (with molar masses of 1,000, 2,000, and 4,000 g/mol) and polyester-based (1,035 g/mol). The weight fraction of sol has been measured, as well as the elastic shear modulus of the gels. It has been found that the statistical theory of network formation predicts a weight fraction of sol in agreement with the experimental results, but its standard combination with the theory of rubber elasticity disagrees significantly with the elastic modulus measured. This suggests a discrepancy between theory and experiment in terms of elastically active chains. In contrast, the assumption that all nodes in the gel, or even in the system, are elastically active gives much better predictions for the system considered.

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Section: Discussionsupporting

confidence: 79%

Section: Discussionmentioning

confidence: 99%

Section: Network Formationmentioning

confidence: 99%

Section: Network Formationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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An experimental and analytical study of the elasticity of model polyurethane networks crosslinked by tri- and quadriisocyanate

2009

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Network Formation

Dušek

2006

Materials Science and Technology

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The synthesis of pyridyl‐substituted polyurethanes and copolyurethanes

Dzo‐Song‐O

Bouchal

Bleha

et al. 1995

Angew. Makromol. Chem.

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New reactive polyurethanes with structure units substituted with pyridine rings were prepared by the polyaddition reaction of diphenylmethane-4,4'-diisocyanate or dicyclo hexylmethane-4,4'-diisocyanate with 2-methyl-2-(4-pyridyI)propane-1,3-diol (MPyP). Copolyurethanes based on this diol were synthesized by a one-or two-step procedure carried out in bulk or diglyme solution using hexane-1,6-diol (HD), a,odihydroxypoly(oxyethy1ene)s of various molecular weights (POE 400, 1 OOO and 2000) or qodihydroxypoly(oxypropy1ene) (PPO 400) as comonomers.Pyridyl-substituted polyurethanes and copolyurethanes were characterized by their 'H and l3C NMR spectra and limiting viscosity numbers [q]. The pyridine units were determined acidimetrically (HCIO,). The reactivity of the OH groups of the pyridine diol towards NCO groups was characterized by determining the rate constants of its reaction with phenyl isocyanate. The obtained value of 2.45 x dm3 rno1-I s-' (25 "C) was by an order of magnitude greater than the rate constant for the addition of hexane-1,6-diol. This difference was interpreted in terms of a catalytic mechanism for the addition of MPyP. ZUSAMMENFASSUNG:Durch Polyaddition von Diphenylmethan-4,4'-diisocyanat oder Dicyclohexylmethan-4,4'-diisocyanat mit 2-Methyl-2-(4-pyridyI)propan-1,3-diol (MPyP) wurden neue reaktive Polyurethane hergestellt, deren Struktureinheiten mit Pyridinringen substituiert sind. Copolyurethane aus diesem Diol wurden in einem Ein-bzw. Zweistufen-prozeB in Substanz oder in Diglyme-Liisung hergestellt, wobei als Comonomere Hexan-l,6-diol (HD), a,oDihydroxypoly(oxyethylen)e mit verschiedenen Molekulargewichten (POE 400, 1 000 und 2000) oder a,wDihydroxypoly(oxypropylen) (PPO 400) eingesetzt wurden. Die erhaltenen Pyridin-substituierten Polyurethane und Copolyurethane wurden durch 'H-NMR-und '3C-NMR-Spektroskopie und durch die Grenzviskositat [q] charakterisiert. Die Pyridineinheiten wurden acidometrisch (HClO,) bestimmt . Die Reaktivitat der OH-Gruppen in MPyP bezuglich der Isocyanat-Gruppe wurde charakterisiert, indem die Geschwindigkeitskonstante der Reaktion von MPyP mit Phenylisocyanat bestimmt wurde. Der erhaltene Wert von 2,45 -dm3 mol-l s s 1 (25 "C) liegt um eine GroRenordnung hoher als die Geschwindigkeitskonstante fur die Addition von Hexan-l,6-diol. Diese Differenz wurde mit einem katalytischen Mechanismus bei der Addition von MPyP interpretiert.

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Structure, equilibrium and viscoelastic mechanical behaviour of polyurethane networks based on triisocyanate and poly(oxypropylene)diols

Cited by 17 publications

References 16 publications

An experimental and analytical study of the elasticity of model polyurethane networks crosslinked by tri- and quadriisocyanate

An experimental and analytical study of the elasticity of model polyurethane networks crosslinked by tri- and quadriisocyanate

Network Formation

The synthesis of pyridyl‐substituted polyurethanes and copolyurethanes

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