Polyethers phenol terminated

Epoxy resins first developed commercially and still completely dominating the worldwide markets are those based on 2,2-bis(4 -hydroxyphenyl) propane, more commonly known as bisphenol A (as it is produced by condensation of phenol with acetone) and l-chloro-2,3-epoxy-propane, also known as epichlorohydrin. It can be seen from the general formula of these resins that the molecular species concerned is a linear polyether with terminal glycidyl ether group... 

The following procedure was used to prepare the phenol terminated polyether from 1,5-dibromopentane and HMS. HMS, 1.7398 g (0.0077 mole) and 0.5255 g (0.00016 mole) TBAH were dissolved into 20 ml of 50% aqueous NaOH. 1,5-Dibromopentane, 1.4993 g (0.0065 mole) was dissolved into 30 ml of toluene and added to the reaction mixture with vigorous stirring. The reaction was continued at 90 C for 18 hr. After separating the organic phase and washing with dilute HCl and distilled water, the solution was poured into methanol thus precipitating the polymer. The obtained polymer, 1.30 g, was purified twice by precipitation into methanol from hot filtered toluene solutions, the presence of phenol chain ends was confirmed by IR and NMR spectroscopies. 

The following procedure was used to end cap the phenol terminated polyether of 1,5-dibromopentane and HMS. To 10 ml of 50% aqueous NaOH, 0.2037 g (0.0005 mole) TBAH was added and dissolved. A solution of 0.4816 g of the polyether and 1.141 g (0.0074 mole) of 1-bromopentane in 12 ml of nitrobenzene was added to the reaction mixture. The reaction was continued at 80 C for 12 hrs. with vigorous stirring. The end capped pol)nner was isolated by pouring the washed organic phase into methanol. The pol3nner... 

Heitz synthesized polymers with two phenolic end groups by carrying out the polymerization in the presence of a biphenol. Block polyether-polycarbonate and polyether-polyester carbonates were synthesized from these blocks. Percec also prepared a bifunctional PPO by polymerization of 2,6-dimethylphenol in the presence of 2,2 -di(4-hydroxyphenyl-3, 5-dimethylpropane). Etherification of the blocks with chloromethylstyrene gave reactive oligomers that were cross-linkable. When monofunctional PPO was reacted with chloromethyl styrene the resulting styryl-substituted polymers formed comb-like structures on polymerization and could be copolymerized with vinyl monomers. Alternatively, Meijer was able to coredistribute phenol-terminated polymers with PPO to produce block copolymers. ... 

There are two specific groups in this series of products (a) neutral urethane polyethers (112) that have to be activated with catalysts when used as second components in urethane coatings, which can be easily transformed into isocyanate-terminated polymers when reacted with additional isocyanate (b) basic urethane polyethers (113. 114) having hydroxyls activated by tertiary amine nitrogen present in the chemical chain of the product and that are very reactive second components of urethane coatings. They can also be converted into isocyanate-terminated polymers, but their stability is very limited (12-24 h). They are stable when immediately blocked by means of phenol, alcohols, or other suitable blocking agents. 

This technique has found the following applications in addition to those discussed in Sections 10.1 (resin cure studies on phenol urethane compositions) [65], 12.2 (photopolymer studies [66-68]), and 13.3 (phase transitions in PE) [66], Chapter 15 (viscoelastic and rheological properties), and Section 16.4 (heat deflection temperatures) epoxy resin-amine system [67], cured acrylate-terminated unsaturated copolymers [68], PE and PP foam [69], ethylene-propylene-diene terpolymers [70], natural rubbers [71, 72], polyester-based clear coat resins [73], polyvinyl esters and unsaturated polyester resins [74], polyimide-clay nanocomposites [75], polyether sulfone-styrene-acrylonitrile, PS-polymethyl methacrylate (PMMA) blends and PS-polytetrafluoroethylene PMMA copolymers [76], cyanate ester resin-carbon fibre composites [77], polycyanate epoxy resins [78], and styrenic copolymers [79]. 

Heat-curing systems are based on a combination of hydroxy-terminated polyesters or polyethers and blocked polyfunctional isocyanates. When the temperature is raised, the blocking agent is removed and the free isocyanate groups react with the hydroxy groups to effect cure. The usual blocking agent is phenol and a typical blocked isocyanate is prepared by reaction of trimethylol-propane (1 mole), tolylene diisocyanate (3 mole) and phenol (3 mole) ... 

---