Homo-polyesters

Although PETP is not widely used as a plastics material, two applications, one long established and one a more recent development, are important. These are biaxially oriented film and biaxially oriented bottles, which are suitable for carbonated drinks. In the manufacture of both products, the following stages apply  

The purpose of the orientation is to improve the barrier properties, while allowing thinner bottles to be made rigidity, strength and toughness are also enhanced. 

Other thermoplastic polyesters have been reported, including copolyesters based on 1,4-cyclohexylenedimethylene glycol and terephthalic acid and polymers and copolymers of p-hydroxybenzoic acid. Little is known about established applications. Hot melt adhesives, based on polyesters made from adipic or phthalic acids with mono- or di-ethylene glycols or 1,4-butane diol, find use in shoe manufacture. 

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The first papers on isohexide based semi-aromatic homo-polyesters were published by Thiem et al. in 1984 [10,11]. They prepared polyesters from all three isohexides by melt condensation with terephthaloyl chloride at elevated temperatures (Figure 9.3). Colourless, brittle oligomers were obtained with Mn 3000-8000. These materials exhibited very high TgS - that is. 

Homo-polyesters of isohexides and linear aliphatic diacids have been reported by various groups (see Table 9.5). Braun et al. reported the synthesis of polyesters from isosorbide or isomannide with a variety of linear aliphatic acid dichlorides (C4-C16) via melt condensation, giving relatively high molecular weight polymers [12]. Comparable polyesters from all three isohexides were prepared by Okada [36-38], Noordover et al. also described the synthesis... 

Table 9.5 Properties of the homo-polyesters derived from isohexides and various aliphatic diacids.

Horlbeck, G., Siesler, H. W., Tittle, B., and Trafara, G., Characterization of polyether and polyester homo- and copolymers prepared by ring-opening poljnnerization with a new catalytic system. Macromolecules. 10. 284-287, 1977. 

Aliphatic polyesters based on monomers other than a-hydroxyalkanoic acids have also been developed and evaluated as drug delivery matrices. These include the polyhydroxybutyrate and polyhydroxy valerate homo- and copolymers developed by Imperial Chemical Industries (ICI) from a fermentation process and the polycaprolactones extensively studied by Pitt and Schindler (14,15). The homopolymers in these series of aliphatic polyesters are hydrophobic and crystalline in structure. Because of these properties, these polyesters normally have long degradation times in vivo of 1-2 years. However, the use of copolymers and in the case of polycaprolactone even polymer blends have led to materials with useful degradation times as a result of changes in the crystallinity and hydrophobicity of these polymers. An even larger family of polymers based upon hydroxyaliphatic acids has recently been prepared by bacteria fermentation processes, and it is anticipated that some of these materials may be evaluated for drug delivery as soon as they become commercially available. 

Undin J, Plikk P, Finne-Wistrand A, Albertsson A-C (2010) Synthesis of amorphous aliphatic polyester-ether homo- and copolymers by radical polymerization of ketene acetals. J Polym Sci A Polym Chem 48 4965 973... 

Malberg S, Plikk P, Fiime-Wistrand A, Albertsson A-C (2010) Design of elastomeric homo-and copolymer networks of functional aliphatic polyester for use in biomedical applications. Chem Mater 22 3009-3014... 

Much work has been done on the incorporation of castor oil into polyurethane formulations, including flexible foams [64], rigid foams [65], and elastomers [66]. Castor oil derivatives have also been investigated, by the isolation of methyl ricinoleate from castor oil, in a fashion similar to that used for the preparation of biodiesel. The methyl ricinoleate is then transesterified to a synthetic triol, and the chain simultaneously extended by homo-polymerization to provide polyols of 1,000, 000 molecular weight. Polyurethane elastomers were then prepared by reaction with MDl. It was determined that lower hardness and tensile/elongation properties could be related to the formation of cyclization products that are common to polyester polyols, or could be due to monomer dehydration, which is a known side reaction of ricinoleic acid [67]. Both side reactions limit the growth of polyol molecular weight. 

Several excellent reviews have recently been published that describe the broad field of degradable biomedical polymers [9,10]. Well-known hydrolytically degradable polymers developed or being developed for biomedical used include homo- and copolymers of polyamides (usually derived from amino adds), polyesters, polyanhydrides, poly(ortho ester)s, poly(anfido amines), and poly(P-amino esters). This chapter is focused on polyacetals, which... 

Chem. Descrip. Decabromodiphenyl oxide CAS 1163-19-5 EINECS/ELINCS 214-604-9 Uses Flame retardant tor thermoplastics and fibers, ind. HIPS, glass-reinforced thermoplastic polyester molding resins, LDPE extrusion coatings, PP (homo and copolymers), ABS, nylon, PBT, PET, PU, SBR latex, textiles, rubber... 

Chem. Descrip. 2-Hydroxy-4-methoxybenzophenone CAS 131-57-7 EINECS/ELINCS 205-031-5 Uses UV absorber, light stabilizer for rigid and flexible PVC, vinyl homo-and copolymers, PS, styrenic copolymers, acrylics, cellulosics, epoxy resins, polyesters, PU, polyacetals, coatings, sunscreens Regulatory DOT nonregulated... 

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