Aromatic polyols

Hsu, C., Zhao, M. and Bergstrom, L., Aromatic polyol end-capped unsaturated polyetherester resins and resin compositions containing the same... 

The aromatic polyols resulting from the reaction can be mixed with commercial polyols, blowing agents, surfactants, catalysts, and polymeric isocyanates to produce a rigid polyurethane foam. n compared w control foams produced from commercially available polyester polyols, the foams produced from reclaimed materials were found to have essentially the same properties. 

Thesecompounds, widely employed at the outset of the development of polyurethanes have been displaced from their market by polyether-polyols. For the production of rigid foams however, use is still made of aromatic polyols produced by the transesterification of dimethyl terephthalate by glycoL... 

Mannich polyols is a very important group of aromatic polyols obtained by the alkoxylation with propylene oxide (PO) [(and/or ethylene oxide (EO)] of the Mannich bases obtained by classical Mannich reaction between phenols (for example phenol, p-nonylphenol), formaldehyde and alkanolamines (diethanolamine, diisopropanolamine, monoethanolamine, monoisopropanolamine and so on). Synthesis of Mannich polyols is divided into two important steps ... 

Mannich polyols are aromatic polyols, which confer excellent physico-mechanical, thermal and fire proofing properties to rigid PU foams. Mannich polyols, especially those based on p-nonyl phenol, have a very good compatibility with pentanes used as blowing agents (for example sucrose polyether polyols have a poor compatibility with pentanes, giving emulsions at normal concentrations for foaming, but not real solutions). 

Simultaneous alkoxylation of bisphenol A and an aromatic amine as second polyol is a variation used to obtain highly aromatic polyols. 

By using the synthesised hydroxyalkyl carbamates of melamine as polyols, rigid PU foams were obtained with good physico-mechanical properties, low friability and inherent self extinguishing properties. A highly aromatic polyol, based on the reaction of benzoguanamine with ethylene carbonate was successfully synthesised [4]. 

Of course the thermal stability and char yield depend on the polyol structure too and the aromatic polyols are superior to aliphatic polyols from this point of view. This is the reason for the extremely rapid growth of aromatic polyester polyols, of low functionality, low viscosity and low cost. 

A very interesting bromine aromatic polyol is obtained by the Mannich type reaction between 2,4 dibromophenol (or 2,6 dibromophenol) with diethanolamine and formaldehyde [28] or better still with oxazolidine [29], followed by the propoxylation of the resulting Mannich base with 2-3 mols of PO [28, 29] (reactions 18.6). 

By using the principles of this classic reaction, new aromatic polyols were created, based on the reaction between dimethyl phthalate, dimethyl isophthalate and dimethylterephthalate with diethanolamine, using sodium or potassium methylate as catalyst (reactions 19.2, 19.3 and 19.4) ... 

The amidic polyols represent a new generation of aromatic polyols for rigid PU foams, with an high application potential, all the raw materials used, dimethyl esters, dialkanolamines and PO being produced in large quantities industrially. 

Aromatic polyols and triazinic polyols lead to polyurethanes with superior fire resistance due to the high char yield generated during the burning process. Sometimes, the rigid polyurethanes based on aromatic and triazinic polyols have an intrinsic flame retardancy (gives self-extinguishing foams without the addition of flame retardants). 

Flame retardant rigid PU foams, due to their high aromaticity, and high crosslink density are easier to be obtain. An aromatic polyol has a supplementary contribution to improving the fire resistance (for example Mannich polyols, novolak polyols, triazinic polyols based... 

Yang, L. and Johnson, K., Cured thermosets and glass-reinforced composites from unsaturated polyetherester resins, US Patent 5 684 086, 1997. Hsu, C., Zhao, M. and Bergstrom, L., Aromatic polyol end-capped unsaturated polyetherester resins and resin compositions containing the same... 

The increased absorption, as well as the bathochromic shift, of boric compounds with aromatic polyols are the basis for a great variety of analytical determinations of boron. Thus, the reaction of B(OH)3 with alizarin in cone. HaS04 to form the stable ester is probably the most common procedure (22, 57). The orange-red colored curcumin-borate ester has a very high molar extinction coefficient which makes this compound a powerful means to detect even traces of boric acid 68). 

In section C6 the application of absorption spectroscopy for the determination of boric-aromatic polyol complexes has been described. Some more specific examples shall be given here. 

Aromatic Polyesters Engineering thermoplastics prepared by polymerization of aromatic polyol with aromatic dicarboxylic anhydride. They are tough with somewhat low chemical resistance. Processed by injection and blow-molding, extrusion, andftiermoforming. Drying is required. Used in automotive housings and trim, electrical wire j acketing, printed circuit boards, and appliance enclosures. 

Other tertiary recycling processes that have been developed include a Freeman Chemical Corp. process to convert PET bottles and film to aromatic polyols used for manufacture of urethane and isocyanurates. Glycolized PET, preferably from film, since it is often lower in cost than bottles, can be reacted with unsaturated dibasic acids or anhydrides to form unsaturated polyesters. These can then be used in applications such as glass-fiber-reinforced bath tubs, shower stalls, and boat huUs. United States companies that have been involved include Ashland Chemical, Alpha Corp., Ruco Polymer Corp., and Plexmar. Unsaturated polyesters have also been used in polymer concrete, where the very fast cure times facilitate repair of concrete structures. Basing polymer concrete materials, for repair or precast applications, on recycled PET reportedly leads to 5 to 10 percent cost savings and comparable properties to polymer concrete based on virgin materials. However, they are still approximately 10 times the cost of portland cement concrete. There appears to be little commercial application of these processes at present. 

Trade name of Conap Inc. Aromatic diamine. Aromatic diamine polyol adduct. Aromatic diamine polyol adduct. Aromatic polyol. Aromatic polyol. Aromatic polyol. Unknown composition. Aromatic diamine polyol adduct. 

Practically, for better control, PUs are synthesized using three different components Dls (ahphatic or aromatic), polyols (mostly diols or triols), and chain extenders (diols or diamines). 

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