Ethoxylate urethane polymers

HydrophobicaHy Modified, Ethoxylated Urethane. HEUR associative thickeners are in effect poly(oxyethylene) polymers that contain terminal hydrophobe units (66). They can be synthesized via esterification with monoacids, tosylation reactions, or direct reaction with monoisocyanates. There are problems associated with aH of the methods of synthesis. The general commercial procedure for their synthesis is by a step-growth addition of... 

During these developments, hydrophobically modified ethoxylated urethane (HE UR) thickeners were synthesized and patented (6, 7). Their application in coatings was discussed, but the emphasis was on improved barrier properties (8), not on rheological influences. The HEUR polymers of the... 

Hydrophobically modified, ethoxylated urethanes (HEURs) are the thickeners of choice in exterior coatings and in corrosion-resistant, high-gloss industrial latex finishes. This chapter presents an overview of our research efforts and discusses approaches to the synthesis of HEUR polymers with different molecular architectures, geometrical influences on solution properties, and viable mechanisms by which this class of associative thickener effects desirable coatings rheology and applied film properties. 

Typical examples are networks in aqueous solutions of polymers with short hydrophobic chains attached at both chain ends (telechelic polymers), such as hydrophobic poly(ethylene oxide), hydrophobic ethoxylated urethane (called HEUR) [1-5], hydrophobic poly(A -isopropylacrylamide) [6,7], poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide) triblock copolymers [8-10], etc. These networks are analogous to the polymer networks whose elastic properties are studied in Chapter 4. They differ, however, in the important point that the network junctions can break and recombine. We extend the theoretical framework of rubber elasticity to suit for the study of polymer networks with temporal cross-link junctions. 

The ability of surfactant binding is enhanced through the hydrophobic interaction between polymer hydrophobes and surfactant hydrophobes. Typical model polymers such as hydrophobically ethoxylated urethane (HEUR), ethyl hydroxyethyl cellulose (EHEC), and hydroxypropyl methyl cellulose (HPMC) have been the focus of study. 

Finally, by way of illustration, we mention a polymer type currently receiving much attention. The polymer is referred to as hydrophobically modified ethoxylated urethane (HEUR), the reaction product of a PEG and a diisocyanate, end-capped with a long chain alcohol or amine. HEURs are already recognized as having much potential as associative thickeners in coating formulations. Their structure suggests they will show pronounced interaction with surfactants in solution and this is indeed the case. Here we refer to two recent studies. The first by Hulden (95) included surface tension studies of the polymer... 

In addition, hydrophobically modified ethoxylated urethanes (HEUR) are prepared by hydrophobe capping of urethane prepolymers. Comb, block and star HEUR s have been synthesized. (Schemes 1.2-1.4) [27]. Such polymers are very effective associative thickeners for urethane paints and coatings. 

In the second study Wang and Winnik [6] reported pyrene probe fluorescence experiments on PEO polymers end-capped with n-hexadecyl groups through urethane linkages. These polymers are examples of hydrophobically-modified ethoxylated urethane (HEUR) associative thickeners (Fig. 2.7). Two... 

A second route could be the copolymerization of the unsaturated urethane obtained from the reaction of the isocyanate unit with an ethoxylated hydrophobe. Only marginal changes in solubility would be noted with water-soluble monomers. Routes of this nature promise new categories of water-soluble ionogenic polymers with the salts of strong acid, that have not been available. The development of these areas will depend upon finding unique properties specific to a given application area. 

Hyflex silane, Y-5889 OSi product, ethoxylated propylsilane Epoxy polyester, urethane Lower viscosity, higher loading potential, faster dispersion, improved physical properties, high polymer compatibility... 

The urethane methacrylate polymer which contains no soft-block and the ethoxylated bisphenol A/MMA copolymer both have relatively low values of K q and their composites have fracture toughnesses approximately double that of the respective polymer. The urethane methacrylate polymer which contains a polyol soft-block, on the other hand, has a fracture toughness which is approximately twice that of the other polymers, but for the composite Kiq is increased only modestly. Thus, the higher the fracture toughness of the polymer then the less is the fracture toughness of the particulate composite enhanced relative to it. 

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