Urethane structure-property relationship

Zdrahala R J and Critchfield F E (1982) RIM Urethanes Structure/Property Relationships for Lineal Polymers, in Reaction Injection Molding and Fast Polymerization Reactions (Ed. Kresta J E) Plenum Press, New York, pp. 55-62. 

An in-depth understanding of structure-property relationships is perhaps the most important concern for the urethane formulation chemist. Material design objectives often go far beyond physical property requirements and may also include considerations like processing characteristics (i.e., compatibility, reactivity,... 

The composition of urethane acrylates can be varied In order to achieve certain end properties required by the Intended application. The structure-property relationships discussed In this paper can provide guidance In the intelligent design of this class of radiation cure oligomer. 

An alternate approach to increase compliance of urethane block copolymers is to vary the structure of the soft polyether block to lower the initial modulus. In our analysis of structure-property relationship of the block copolyurethanes, it would appear that a polyether segment based on a... 

Sartoii, S., Bofflto, M., Seraflni, R, Caporale, A., SUvestri, A., Bemardi, E., Sassi, M.R, Boccafoschi, R, CiardeUi, G., 2013. Synthesis and structure-property relationship of polyester-urethanes and their evalnation for the regeneration of contractile tissues. Reactive and Functional Polymers 73,1366-1376. 

O Sickey, M. J., Lawrey, B. D., Wilkes, G. L. (2003), Structure-property relationships of poly(urethane-urea)s with ultralow monol content poly(propylene glycol) soft segments. Part III Influence of mixed soft segments of ultralow monol poly(propylene glycol), poly(tetramethylene ether glycol), and tii(propylene glycol), J. Appl. Polym. Sci., 89, 3520-9. 

Contradictory results were published on the structure-property relationships of PA/TPU systems [17,98]. Note that in these blends the possible H-bonding between the carbonyl group of the urethane linkage and secondary amine groups of the amide should yield some compatibilization effect. 

Urethane performance characteristics highly depend on the backbone structure R and R ), its length, as well as the functionality of both isocyanate and alcohol. Depending on the desired physical characteristics, the right balance of polyols and isocyanates is required [4]. While an extensive knowledge base on this matter exists [3, 4], some important aspects of polyurethane structure-property relationships in conjunction to the kinetics of their erne and blending interactions have not been investigated effectively. This is the focus of the present work. 

Bogart, V, John, W. C., Gibson,P. E.,Cooper, S. L. (1983), Structure- operty relationships in polycaprolactone-polyurethanes, J. Pofynt. Sci., Polym. Phys. Ed., 21,65-95. Bogdanov, B., Toncheva, V., Schacht, E., Finefli, L., Sartib, B., Scandola, M. (1999), Physical properties of poly(ester-urethanes) prepared Irom diflerent molar mass polycaprolactone-diols,Po/yraer, 40, 3171-82. 

Frisch, K.C., "Relationship of Chemical Structure and Properties of Rigid Urethane Foams," Journal of Cellular Plastics, 1(2) 325-330 (April 1965). 

Polymer. There is a natural tendency for polymer scientists to assume that the relationships between polymer structure and properties carry over from the solid polymer to its foams as well. To some extent this is true. For example, the effects of plasticizers in vinyls and the effects of cross-linking in urethanes are well understood in the solid polymers, and they have parallel effects in the foamed plastics. In general, the properties of polymers in the solid phase can be reflected in their foams in the following ways. 

Aqueous PU dispersions based on tetramethylxylene diisocyanate, polyesterols or polyetherols polyols and, as chain extender, an aliphatic diamine, were synthesised and their particle sizes, surface free energies, viscosities and dispersion stabilities and property/structure relationships determined. Coherent, dry, thin sheet materials were produced from these aqueous dispersions and characterised by DSC, DMTA and tensile testing. They were found to exhibit good mechanical properties similar to those of urethane-urea copolymers obtained by water-free methods. 31 refs. 

Hydrophobically associating polymers are water soluble polymers containing a small amount of hydrophobic functionality. The conformation of the polymer in solution is influenced by a variety of structural parameters. Polymer architecture, such as random or blocky arrangement of the hydrophobic groups will have a significant influence on polymer conformation and interactions in solution. The presence of hydrophobic functionality can result in inter- or intramolecular association or some combination of both. The relative amounts of these types of association will affect the conformation of the molecules in solution and in turn the properties of the solution. While many chemically different systems, such as hydrophobically modified cellulose [19], urethanes [15], and others [11] have been described in the literature, we will focus on only a few critical structures. To illustrate the relationships between structure and the observed solution phenomena, three types of hydrophobically associating polymers will be discussed as shown in Fig. 3.1. These are ... 

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