Polyester Structure

H. Boenig, Ensaturated Polyesters Structures and Properties, Elsevier Science, Inc., New York, 1964. 

Boenig, Unsaturated Polyesters Structure and Properties , Elsevier, NY (1964) 11) I. 

The final properties depend not only on unstaturated polyester structure but also on a number of other parameters, such as the nature and proportion of unsaturated comonomer, the nature of the initiator, and the experimental conditions of the crosslinking reaction. Moreover, since polyester resins are mainly used as matrices for composite materials, the nature and amount of inorganic fillers and of reinforcing fibers are also of considerable importance. These aspects have been discussed in many reviews and book chapters and are beyond the scope of this chapter.7-9... 

RA Gross. Bacterial polyesters Structural variability in microbial synthesis. In SW Shalaby, ed. Biomedical Polymers Designed-to-Degrade Systems. Cincinnati, OH Hanser/Gardner, 1994, pp 173-188. 

This is potentially a method to make complicated polyester structures such as star-shaped polyesters. 

A variation of the aromatic polyester structure was utilized by Hawker et al. when they described hyperbranched poly(ethylene glycol)s and investigated their use as polyelectrolyte media [76]. The highly branched structure implies that no crystallization can occur. Linear poly(ethylene) glycols usually crystallize, which has a detrimental effect on their use as polyelectrolyte media. 

A combination of enhanced reactivity and reduced viscosity for alkyd resins has been achieved by using hyperbranched polyester structures as discussed in Sect. 4.2.3 [ 123]. This study clearly showed the benefits of using highly branched structures in coating applications to obtain improved properties. 

The formation of polyesters from a dialcohol (diol) and a dicarboxylic acid (diacid) is used to illustrate the stepwise kinetic process. Polymer formation begins with one diol molecule reacting with one diacid, forming one repeat unit of the eventual polyester (structure 4.3) ... 

Lactomes may also be polymerized by ring-opening anionic polymerization techniques. While the five-membered ring is not readily cleaved, the smaller rings polymerize easily producing linear polyesters (structure 5.46). These polymers are commercially used as biodegradable plastics and in PU foams. 

Preliminary structural studies of cutin and suberin breakdown involved examination of 13C NMR spectra for insoluble residues that were resistant to chemical depolymerization. In cutin samples, flexible CH2 moieties in particular were removed by such treatments, but CHOCOR crosslinks and polysaccharide impurities were retained preferentially. A concomitant narrowing of NMR spectral lines suggested that the treatments produced more homogeneous polyester structures in both cases. Our current studies of cu-ticular breakdown also employ selective depolymerization strategies with appropriate enzymes (1,28). 

Another resin application based on the same hyperbranched polyester structure described herein is low-VOC alkyds, which have very low viscosity and high reactivity compared to conventional high-solid alkyds. Other resin structures are unsaturated polyesters, polyurethane dispersions, and epoxides. ... 

Polyester acrylates Acrylated polyesters are prepared by reacting the OH group of polyesters with acrylic acid or hydroxy acrylate with acid groups of the polyester structure. Polyester acrylates are often low-viscosity resins requiring little or no monomer ll They produce coatings and adhesives dominated by the polyester structure used in the oligomer. They are used for pressure-sensitive adhesives and... 

Asrar. J.. Thomas, O., Zhou, Q. and Blumstein, A. Thermotropic liquid crystalline polyesters Structure property relationship. Proc. 28th Macromol. Symp. IUPAC, U. Mass., Amherst, MA, p. 797, 1982... 

Polyester fibers, similar to polyamide fibers, represent another important family of fiber. Polyester fiber was discovered in England in 1941 and commercialized in 1950. Two common trade names of polyester are Dacron in the US and Terylene in the UK. The term polyester fiber represents a family of fibers made of polyethylene terephthalate. Dimethyl terephthalate is reacted with ethylene glycol in the presence of a catalyst, antimony oxide, to produce polyethylene terephthalate or polyester. The chain repeat structure of PET is given in Fig. 4.6. Although polyesters can be both thermosetting and thermoplastic, the term polyester has become synonymous with PET. Note that the PET chain structure is different from the simpler structure of nylon or polyethylene. In PET, the aromatic ring and its associated C-C bonds provide a rigidity to the structure. The polyester structure is also bulkier than that of nylon or polyethylene. These factors make polyester less flexible than nylon and polyethylene, and the crystallization rate of PET slower than that of nylon or polyethylene. Thus, when polyester is cooled from the melt, an appreciable amount of crystallization does not result. 

Chopped strand mat. This consists of chopped strands (bundles of glass filaments) about 2 in long bound togther by a resinous binder. This type of mat is used extensively in glass-reinforced polyester structures. 

High performance in the synthesis of hydrolytically resistant polyurethanes was obtained by using in the polyesterification reaction, very hydrophobic fatty dimer acids and fatty dimer alcohols, products obtained from vegetable oils (see Chapter 12.5). The use of fatty dimeric acids and fatty dimeric alcohols (obtained by the hydrogenation of dimeric acids or dimeric esters) to build the polyester structure, creates an extremely high hydrophobic environment alongside a low concentration of labile ester bonds. 

The development of highly crosslinked rigid polyisocyanurate foams opens an excellent area of applications for polyester polyols [4-8]. The required polyols do not need high functionality and the plasticising effect of polyester structures is extremely beneficial for these highly crosslinked systems [6]. The first polyester polyols used for these applications were low viscosity polycondensation products of AA with ethyleneglycol (EG) or diethyleneglycol modified with phthalic anhydride or triols. 

The polyester structure has been adapted for use in radiation-cured coatings. Low molecular weight, linear polyesters have been made in which the terminal hydroxyl groups have been esterified with acrylic acid. These oligomers have low viscosity and are used increasingly in coatings cured by UV or electron-beam radiation (21). 

Polyester Structure ASTM Weight Loss in TOC11... 

More recently, Lopez-Luna et al. [54] reported the successful enzyme-mediated syntheses of polyester structures in SCCO2 and R-134a. Lipase-mediated synthesis of relatively high molecular weight poly(S-valerolactone) (PVL) was reported in SCCO2 and liquid R-134a solvent media. However, they found that polymers and copolymers... 

We have successfully synthesized ATF which can be used with FPE up to 80% but no less than 20%. ATF improves processability. Cross-linked ATF provides flexibility and thermal stability to the fluorenone polyester. The fact that the polyester structure does not contain nitrogen is a potential advantage in fire-resistant fiber applications, since there is no likelihood of HCN generation during burning. Because of high glass transition temperature of fluorenone polyesters, these polymers can be used as heat-resistant fibers. 

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