Brominated polyol

The brominated polyol had 4.1 hydroxy groups, whereas the other three polyols had slightly lower functionality. Applications of four polyols in... 

Bromine containing polyols are very effective, reactive flame retardants. One of the most representative bromine polyols used in rigid and flexible flame retardant PU foams is 2,3 dibromobutene diol (Figure 18.3) [25] ... 

Brominated Reactive Tfetrabromobisphenol A (TBA) Brominated polyols Tfetrabromophthalic anhydride Additive Decabromodiphenyl oxide (DBDPO) TBA derivatives Hexabromocyclodecane/do decane Hexabromodiphenoxyethane Brominated polystyrene... 

With regard to reactive flame-retardants, two routes can be followed to improve thermal stability and fire behavior of PU foams use of brominated or phosphorus-containing polyol or, for rigid foams, the introduction inside polymer backbone of more thermally stable structure than urethane, mainly isocyanurate, but also uretidione rings or carbodiimide.19... 

Trialkyltin alkoxides prepared by evacuation of methanol from a mixture of an alcohol and trialkyltin methoxide are easily oxidized by bromine in the presence of trialkyltin alkoxide as HBr scavenger, producing the desired aldehyde and ketone efficiently [324]. This oxidation is more feasible on organotin alkoxides derived from secondary alcohols than those from primary alcohols, and enables regioselective oxidation of polyols [325]. The regioselectivity in oxidation of vicinal secondary alcohols was also examined [326], and the empirical informative results were invoked for access to namenamicin A-C disaccbarides (Scheme 12.177) [327]. 

A special group of polyols for rigid PU foams is the group of reactive flame retardant polyols containing phosphorus, chlorine or bromine, which confer fire resistance to the resulting PU (Chapter 18). 

The bromine diol (18.5), in combination with sucrose polyols gives rigid PU foams with excellent fire retardancy properties [3, 24]. 

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). 

Very interesting reactive flame retardants were used successfully in the fabrication of flame retardant rigid PU foams by Solvay under the name of Ixol polyols. These polyols are triols based on epichlorohydrin and brominated unsaturated diol. Ixol polyols have chlorine, bromine and phosphorus in each structure [3, 44, 45]. 

The fire resistance of polyurethanes is based on the introduction of flame retardant compounds including polyols, containing chlorine, bromine or phosphorus in their structure. The polyols containing chlorine, bromine or phosphorus are linked chemically in the polyurethane structure and lead to self-extinguishing polyurethanes, with a permanent flame retardancy. 

These foams can then be extended into the area of flame-retardant materials, where methyl oleate-polyesters were used as polyols in the synthesis of silicon-containing polyurethanes [89]. Despite not strictly being foams, methyl oleate, soybean and sunflower oils have also been investigated to produce semi-rigid flame retardant materials [90]. In this instance, they were brominated, acrylated and then radically copolymerized with styrene to form the polymeric material. 

Other brominated FRs from Dead Sea Bromine are reactive types that should be compatible with any solvent system that is utilised as a polymerisation medium. So, aliphatic materials such as FR-513 (in alcohol) and FR-522 (diol) have good solubility in the polyol or trichloropropylphosphate (TCPP) systems used for the production of polyurethane foams. 

Tribroinoneopentyl alcohol (TBNPA) is a reactive FR containing more than 70% aliphatic bromine. It is exceptionally stable and is particularly suitable where thermal, hydrolytic, and light stability are required. It is highly soluble in polyether polyols, making it particularly suitable for use in polyurethane polymers. 

---