Trifunctional polyol

Flexible foam. This is made by mixing long trifunctional polyol with isocyanate to form the polyurethane, and adding a little excess isocyanate and water to the reaction to produce carbon dioxide which produces the foam. The largest use is in furniture, with smaller amounts in auto seating, mattresses, rug underlay, textiles, and packaging. 

Materials Two commercial polypropylene glycols (polyols) of different functionality were used. The trifunctional polyol is Union Carbide NIAX 16-56, and the difunctional polyol is Union Carbide NIAX 2025. Each has an equivalent weight approximating 1.00 kg. The polyols were dried with bubbling dry nitrogen while... 

Network Synthesis (4) Solid MDI was weighed into a flask and an equivalent amount of polyol added. The mixture was heated to about 40°C to dissolve the MDI. The mixture was then cooled to room temperature and degassed for several minutes under vacuum in order to remove dissolved air. Catalyst was then added and the contents of the flask mixed under vacuum to ensure uniformity and then poured into a mold. All operations were carried out in a dry glove bag to minimize reaction with atmospheric water. The cross-linking process was also carried out in dioxane solution at 70% volume fraction of solids. Polyurethane networks with different crosslink densities were prepared by varying the ratio of difunctional and trifunctional polyols. All samples were extracted with dioxane to remove unreacted and uncrosslinked materialbefore swelling. 

Chart 11.3 Structure of part of a network formed by the reaction of a difunctional epoxide with a trifunctional polyol. 

Chem. Descrip. Trifunctional polyol (e-Caprolactone triol)... 

The adhesive used was a model semi-structural PU, similar to one described in an earlier work [7]. The two component formnlation consisted of methylene bis-4-cyclohexyl isocyanate prepolymer and trifunctional polyols with molecnlar masses in the range 500-900. A small amount of tin catalyst (UL-28, Witco Chemicals) was also present. The PU was used as control without additives and was modified by the following silanes ... 

Figure 7.25 Viscosity of a trifunctional polyol (Luprane 2090) in the presence of 5wt% C30B (a) and C20A (b) as a function of temperature and time. Reproduced from Ref. [33] with permission.

The reaction was carried out as a one-shot, two-step procedure. At room temperature, dibutyltin-dilaurate (DBTL) was the urethane catalyst. Trifunctional polyols served to crosslink the polyurethane. The temperature was then raised to initiate the MMA polymerization. An example of the Allen et synthesis is as follows. 

Fatty acids and glycerol are products in hydrolysis reaction of triglycerides. Glycerol is a trifunctional polyol obtained as a by-product of soap production (nowadays it is also known as a by-product of biodiesel production). It has been used in the food industry, the pharmaceutical industry, and the cosmetics industry, and especially used as a monomer for alkyd resin and polyurethane in the polymer industry. More recently, hyperbranched polymers are synthesized on the basis of trifunctional reactivity of glycerol. ... 

Scheme 3 gives the reaction route to the preparation of the shape memory TPUs crosslinked by trifunctional polyols. PTMG (M =250) and a molar excess of MDI were first reacted to obtain NCO-terminated prepolymers (NTP), which were... 

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