Hydroxylated polyesters properties

The preparation of hydroxylated polyesters involves reactions of various polyols and polyol combinations with polybasic acids to give a wide range of properties. In the design of these resins, the polyol source is generally determined by the amount of hydroxyl groups available for further reaction of the polyester chain with cross-linking polymers. The polyols most often used as sources of available hydroxyls are pentaerythritol V, trimethylolethane VI, and trimethylolpropane VII. 

Uses PU intermediate producing high< ualily flexible polyester slab foams for use in textile laminates, pkg., filter media, and in noncellular applies, such as coalings, adhesives, and elastomers Features Sal., crosslinked primary hydroxyl polyester rec. where good flexibility and solv. resist, are required Properties Pale liq. m.w. 2600 dens. 9.3 Ib/gal vise. 18,000 cps acid no. 1-2 hyd. no. 50 Lexorez 1101-60A [Inolex]... 

Uses Lipophilic surfactant emulsifier in formulations of liq, and semi-liq. solv. waxes for floors, vehicle waxes and furniture polish preparation of cosmetic creams and lotions polymerization additive for PVC and polyester Properties Liq, sol, in oil sapon, value 145-166 acid value 7.0 max. hydroxyl value 330-358 HLB 8.6 (calculated)... 

Chemical Properties. Trimethylpentanediol, with a primary and a secondary hydroxyl group, enters into reactions characteristic of other glycols. It reacts readily with various carboxyUc acids and diacids to form esters, diesters, and polyesters (40). Some organometaUic catalysts have proven satisfactory for these reactions, the most versatile being dibutyltin oxide. Several weak bases such as triethanolamine, potassium acetate, lithium acetate, and borax are effective as stabilizers for the glycol during synthesis (41). 

Chemical Properties. The chemistry of 1,4-cyclohexanedimethanol is characteristic of general glycol reactions however, its two primary hydroxyl groups give very rapid reaction rates, especially in polyester synthesis. 

TPU is usually made from hydroxyl-terminated polyether or polyester diols, diisocyanates, and bifunctional chain extenders. Since the composition, the synthetic method, molecular weight, and its distribution are all changeable, there are numerous types of TPUs available, and their prices and properties vary significantly. 

Due to the high reaction temperatures required during the last stages of these syntheses, side reactions cannot be avoided. Acetaldehyde, carboxyl endgroups, and vinyl endgroups are formed during PET and PEN synthesis. The formation of 2,2/-oxydiethylene moieties in polymer chains by etherification of hydroxyl endgroups is also a well-known side reaction of EG polyester syntheses.264 These reactions should be carefully controlled since they can exert an important influence on polymer properties such as Ts, mechanical properties, hydrolytic stability, and discoloration. 

The key feature of ethylene glycol (EG) is the hydroxyl group, -OH, one on each of the two carbon atoms. The hydroxyls are responsible for its reactivity EG is a monomer used in the production of polyester polymers. The hydroxyls also give EG its most important physical property its solubility in water. That, linked with its low freeze point, makes EG suitable as an antifreeze and as a deicer. When EG is sprayed on ice, it combines with the water crystals and lowers the freeze point. This causes the mixture to melt and effectively keeps it in the liquid state. 

Together, antifreeze, PET, and polyester polymers account for about 98% of the ethylene glycol produced in the United States. It is also used sometimes as a deicer for aircraft surfaces. The two hydroxyl groups in the EG molecule also make EG suitable for the manufacture of surfactants and in latex paints. Other applications include hydraulic brake fluid, the manufacture of alkyd resins for surface coatings, and stabilizers for water dispersions of urea-formaldehyde and melamine-formaldehyde The hygroscopic properties (absorbs moisture from the air) make EG useful as a humectant for textile fibers, paper, leather, and adhesives treatment. 

Unfunctionalized, i.e., 2-hydroxypropylamide functional, hyperbranched polyesteramides have been tested in powder coating formulations together with stoichiometric (OH/COOH) amounts of acidic polyesters (Uralac). It was anticipated that the reaction of the hydroxyl end groups of the polyesteramide with the carboxylic acid end groups of the polyester would provide a well-crosslinked film with good mechanical properties by polymer/polymer cure. 

Finally, Lecomte and coworkers reported the synthesis of mikto-arm star-shaped aliphatic polyesters by implementing a strategy based on click chemistry (Fig. 36) [162]. Firstly, the polymerization of sCL was initiated by a diol bearing an alkyne function. The chain-ends were protected from any further undesired reaction by the esterification reaction with acetyl chloride. The alkyne was then reacted with 3-azidopropan-l-ol. The hydroxyl function located at the middle of the chain was then used to initiate the ROP of sCL and y-bromo-s-caprolactone. Finally, pendant bromides were reacted successfully with sodium azide and then with N, N-dimethylprop-2-yn-l-amine to obtain pendant amines. Under acidic conditions, pendant amines were protonated and the polymer turned out to exhibit amphiphilic properties. 

Figure 12 presents q as a function of temperature for three hyperbranched polyesters with different end groups. A comparison shows that the properties of hyperbranched polymers are greatly affected by the structure of the terminal groups. The Tg decreases from 35 °C with terminal hydroxyl groups to 15 0 for benzoates and -20 °C for propionates. 

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