Polyesters, linear saturated

Among the high molecular weight aliphatic-aromatic polyesters, the highest commercial volume material is poly(ethylene terephthalate). Most of it is prepared from dimethylene terephtha-late and ethylene glycol by a transesterification reaction  

Often the reaction is carried out in two steps. An excess of two moles of ethylene glycol is used and the first stage of the reaction is carried out at 150-210 °C to form bis(2-hydroxyethyl)terephthalate, a small amount of an oligomer, and methanol, which is removed  

In the second stage the temperature is maintained at 270-285 °C and the reaction is carried out under vacuum at about 1 mm Hg. The bis(2-hydroxyethyl)terephthalate undergoes a transesterification reaction and the excess glycol is removed  

A Study of antimony glycolates as effective catalysts for preparation of poly(ethylene terephthalate) with a varying number of hydroxyethoxy ligands rated them in the following decreasing order of effectiveness  

This led to a suggestion by Maerov that a key step in condensation may involve a chemical reaction that ties up a hydroxy chain end with the catalyst molecule. Introduction of a second hydroxyethoxy chain end is followed by the right electronic bond shift  

The saturated polyesters that find commercial applications are mostly Unear except for some specially prepared branched polymers used in the preparation of polyurethanes. The linear polyesters became 

The synthetic methods that are in general use for the preparations of linear polyesters [15] can be 

Diesters or half esters of dicarboxylic acids or amine salts of the acids are reacted with glycols [19]  

The above transesterification reaction is practical for use with high melting and poorly soluble dicarboxylic acids. In addition, less energy is needed to remove alcohol than water. 

Hydroxy acids, like p-hydroxyethoxybezoic acid or co-hydroxydecanoic acid, are capable of selfcondensation to form polyesters [10]  

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Linear saturated polyesters of low Molecular weight (less than 10,000) can be obtained by condensing a diol with a diacid. Molecular weight can be controlled by adding a monohydric alcohol or monocarboxylic acid. These polymers are used as plasticisers or as polyester diols for making polyurethanes. 

The linear saturated polyesters are hard, semicrystalline thermoplastics that are impact resistant even at low temperatures, smooth and have good wear resistance. Their amorphous fractions have glass temperatures around 50-70 °C. 

M. Katz, Preparation of Linear Saturated Polyesters, Chap. 13 in Polymerization Processes (C. E. Schildknecht, ed. with I. Skeist), Wiley-Intersdence, New York (1977). 

Network polyester resins may be categorized into saturated and unsaturated polyesters. Unlike linear saturated polyesters such as PET, which are made from difunctional monomers, saturated polyesters (glyptal) are formed by the reaction of polyols such as glycerol with dibasic acids such as phthalic anhydride. 

Esteric bonds o 1 -c-o-c- 1 Linear, saturated polyesters Nucleid acids... 

Uses Antioxidant tor polymers, rubber, SBR, polyacetals, linear saturated polyesters, PVC, polyolefins food-contact coatings, polymers, rubber... 

Uses Antioxidant for rubbers, SBR, polymers, polyacetals, linear saturated polyesters, PVC, polyolefins, polyamides antioxidant for food-grade polymers in side seam cements for food-contact containers Regulatory FDA 21CFR 175.300, 178.2010 Manuf./Distrib. Ciba Spec. Chems./Plastic Addit. http //www. cibasc. com Trade Name Synonyms Irganox 1098 [Ciba Spec. Chems. Switzerland http //www.cibasc.com, Ciba Spec. Chems./Plastic Addit. http //w. cibasc.com] Lowinox HD 98 [Great Lakes http //www. greatiakeschem. com]... 

Trimethyl-1,2-dihydroquinoline polymer antioxidant, light metal soldering flux Hydrazine sulfate antioxidant, light-colored rubber N,N -Di-o-tolylethylenediamine antioxidant, linear saturated polyesters N,N -Hexamethylene bis (3,5-di-t-butyl-4-hydroxyhydrocinnamamide) antioxidant, liposomes Phosphatidylcholine antioxidant, liver health maintainance Thioctic acid antioxidant, lube oils Anthranilic acid antioxidant, lubricant Methylcyclohexanol antioxidant, lubricant additives 4,4 -Bis (a,a-dimethylbenzyl) diphenylamine antioxidant, lubricants... 

A large number of polyesters is commercially available. These polymers are conveniently classified into the following types - linear unsaturated polyesters linear saturated polyesters of low molecular weight linear saturated polyesters of high molecular weight network polyesters poly(allyl ester)s and polycarbonates. Each of these groups is considered separately in this chapter. 

The polymers making up this group of polyesters are linear saturated polyesters of molecular weight less than 10 000. Polyesters of this type find commercial application mainly as plasticizers. It may be noted that low molecular weight saturated polyesters of a different kind are also of commercial importance these are hydroxy-terminated polyesters which are used for the preparation of polyurethanes. These intermediate polymers are described in Section 14.3.2.2. 

Polyesters are the reaction product of dibasic acids with polyfunctional hydroxyl-bearing materials. Both the linear saturated polyesters and the unsaturated polyesters have achieved commercial significance. 

The linear saturated polyesters comprises a large class of polymers with a variety of properties. The main types are ... 

PHB (Figure 13.1) is linear saturated polyester, fuUy biodegradable behaving like a thermoplastic polymer [4,6]. It is insoluble in water and soluble in some nonpolar solvents such as chloroform, dichloro-methane and dimethylformamide it is also a semicrystalline material with a high content of crystallinity and high production cost due to its low production rates when compared to other conventional polymers [7,8]. 

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