Incompatible polyols

Polyurethane (PU) materials have been formed by RIM using a commercial isocyanate reacting with either various compatible or incompatible polyol blends, or with slurries containing polyol blends and glass fibres. 

Effects of Plaque Thickness, System Index and Filler ( Filled materials formed using incompatible polyol blend PBA1478 at... 

Figure 3. Tensile stress-strain curves (23°C) of RIM PUs defined in Table I. PUs formed from isocyanate VM10 and (a) compatible and incompatible polyol blends (Series II) (b) incompatible polyol blends and slurries based on PBA1478 (Series I).

At this juncture. It was decided to make a radical formulation change. First, because of the Incompatibility of the Freon 11 with the polyol, the Freon 11 would be removed from the polyol and placed In the Isocyanate component. Second, since 1/1 component ratios are necessary to accommodate the mixing machine, different Isocyanate and polyol components were formulated to establish appropriate viscosities. The final formulation Is shown below. 

Expandable interlayers provide an alternative way for rapid delivery. Migration, even if promoted by an incompatible interlayer, is sometimes not rapid enough to deliver active substances to the surface therefore, a new adaptive concept has been developed recently [53,54], A material utilizing this mechanism contains a phosphorylated polyol (PPOL) interlayer of relatively low decomposition temperature intercalated between layers of nanoparticle. At the early stage of fire action the gaseous degradation products of the interlayer separate the nanolayers and drive them to the surface in the most rapid way. 

Flexural Modulus-Temperature Behaviour. This is shown in Figure 4(a) for various RIM materials PU821to PU221, compared with PU401, where the effects of polyol compatibility versus incompatibility are more evident. In the compatible polyol-based series, reducing triol M (increasing crosslink density) together with increases in HB... 

Figure 4. Variation of flexural modulus with temperature (-30°C to 65°C) for the RIM PUs in Series I and II defined in Table I. Curves show the effects on flexural modulus-temperature behaviour and -30/65°C ratios of polyol composition and added fillers, (a) Polyol blend compatibility/incompatibility Key A, PU221 A, PU421 , PU521 O, PU621 , PU821 , PU401.

Table IV. Tensile Properties (23 °C) of RIM PUs Formed as 3mm Plaques Using Either Compatible (c) Polyols or Incompatible (i) Polyols...

Figure 1 shows that the hard segment MDI-DPG is essentially completely conpatible in the soft segment MDI/Poly G-55-56, a 45% B0 polyol and essentially completely incompatible in the soft segment MDI/Poly G-53-56, an 11% E0 polyol. The theoretical line derived from Equation 1 is in good agreement with the compatible blend. 

PLURACOL POLYOL (25322-69-4) Combustible liquid (flash point 390°F/198°C). Incompatible with oxidizers, sulfuric acid, nitric acid, caustics, aliphatic amines, isocyanates, boranes. 

Precaution Incompat. with phosphorous prods, or polyols thermal decomp, of PU foam made from this mixt. can generate toxic compds. Storage Store under dry, inert gas blanket such as nitrogen to minimize contamination from contad with air and water... 

Natural polyols are incompatible with nonpolar hydrocarbon media. They can be chemically modified into a lipophilic form by transforming them into cyclic ketals (dioxolanes) by condensation with carbonyl compounds (acetone and other ketones and aldehydes) ... 

Materials, West Conshohocken, PA, www. astm.org). In plasticizers, the hydroxyl value includes -OH groups present in any free unesterified alcohol as well as those of the plasticizer molecule itself. In some plasticizers, large hydroxy values signal that the plasticizer may become incompatible on aging. In urethane technology, hydroxyl number is an important factor in the selection of polyols to achieve desired characteristics in elastomers and foams. Wypych G (ed) (2003) Plasticizer s database. Noyes Publication, New York. 

Due to the incompatibility (different polarity and chemical nature) between HS and SS, phase separation occurs in most PUs. The degree of phase separation and domain formation depends on the HS and SS nature and sizes, on the type of the diisocyanate and polyol employed to produce prepolymers, on the type of the chain extender, and on the molecular weight of the SS. It is also influenced by the hydrogen bond formation between the urethane linkages, by the manufacturing process, and reaction conditions [3-6]. 

The reaction between these three components leads to the formation of segmented copolymers characterised by the alternation of hard and soft segments. Hard segments are based on blocks formed by reaction of the di- or multi-functional isocyanate with the chain extender, while the polyol-based units form the soft segments. As a result of the thermodynamic incompatibility between hard and soft segments, PURs are characterised by a biphasic morphology (GunatiUake et al., 2011) (Fig. 6.2). 

A one-part, heat-curing polyurethane adhesive has recently been introduced in which the curative is incompatible, and hence nonreactive, with an isocyanate prepolymer. Upon heating, the finely dispersed polyol curative becomes reactive towards the prepolymer and curing takes place. 

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