Isophthalic acid polyester monomer

EP-4 developed by ERDL is a very flexible polyester based on polyethylene glycol with molecular weight-200 (PEG-200), isophthalic acid (IPA) and maleic anhydride (MAn). Before its use, it is blended with styrene monomer (1 1) and cured at room temperature using cobalt naphthenate (as an accelerator) and methyl ethyl ketone (MEK) peroxide (as a catalyst). This meets the requirements of the main inhibitor and is used for inhibition of DB and CMDB propellants after the application of a barrier coat (generally a rigid polyester such as PR-3). However, it is observed during manufacture of EP-4 that there is a lot of batch-to-batch variation in properties in spite of the strict quality control measures adopted during its manufacture. 

Terephthalic acid (benzene 1,4-dicarboxylate, TPA) and isophthalic acid (benzene 1,3-dicarboxylate, IPA) are reactive bi-functional acids used as monomers to make plastics and coatings. TPA is a starting material for polyethylene terephthalate (PET). TPA and IPA are used to make polyester lacquers and coatings including the internal coatings of food cans. 

Ester-based cascades (e.g., 107) have been prepared[77 80i by using 5-(tert-butyldime-thylsiloxy)isophthaloyl dichloride (108), which was synthesized in high yield from 5-hydroxy-isophthalic acid (Scheme 5.26). The dendron wedges were prepared by treatment of siloxane 108 with phenol to give bis(aryl ester) 109, which was hydrolyzed, or desilylated (HC1, acetone), to generate a new phenolic terminus. Treatment of this free phenolic moiety with monomer 108, followed by hydrolysis, afforded the next tier (110). Repetition of the sequence followed by reaction of the free focal phenols with a triacyl chloride core, (e.g., 86), afforded the fourth tier dendrimer 107 of the polyester aryl series. It was noted that the choice of base (N, A-dimethylaniline) used in the final esterification was critical, since with pyridine bases (pyridine or 4-(dimethylamino)pyridine) facile transesterification resulting in branch fragmentation occurred. 

Another possibility for obtaining imide modified thermoplastic polyesters was to use as a monomer the hydroxy acid made from trimellitic anhydride and aminoethanol. Such a poly(ester-imide) was claimed for injection molding [240]. For the same use, poly(ester-imide)s containing aminophenol/trimellitic anhydride [241],imidised polyfbutylene terephthalate) [242] and a wholly aromatic poly(ester-imide) made from trimellitic anhydride, p-aminobenzoic acid, p-acetoxybenzoic acid, diacetoxybiphenyl and terephthalic and isophthalic acids are known, which showing optical anisotropy [243]. 

These polyester resins use isophthalic acid in place of phthalic anhydride as the saturated monomer. This increases the cost to produce, but it improves physical properties and corrosion resistance. 

For any particular combination of monomers, varying the ratio of generally produced a melting point curve that showed a definite minimum. This is illustrated in Figure 1 for two different systems. For polyesters based on isophthalic acid, p-hydroxybenzoic acid and hydroqulnone, a melting point curve is obtained with a minlmiuB near 50% (on a mole... 

Use of even 10 mole percent of a 1,3-disubstituted phenylene monomer (commonly called a bent comonomer), such as isophthalic acid, in typical polyesters also causes significantly lower melting points (Figure... 

Unlike poly(ethylene terephthalate), the polyester from dimethyl terephthalate and cyclohexane-1,4-dimethylol can be manufactured with initially equivalent monomer quantities. It has improved dyeability, just as in the case of the copolymer of dimethyl terephthalate, ethylene glycol, and 5-10% p-hydroxybenzoic or isophthalic acid. 

PCL (M =70,000-100,000) has been blended with uncured, unsaturated polyester resin which was subsequently cured [170]. The unsaturated oligomeric resin (M =1000) was a copolyester formed from isophthalic acid, fumaric acid and propylene glycol (in the molar ratio 1 1 2.2) and contained 33 wt % styrene monomer. The resins were cured by adding benzoyl peroxide and heating, in stages, from 60 °C to 120 °C. 

The data given in Table 7.17 shows that the precision of the overall method is good. This method is relatively simple and fast. The method has been used to analyse experimental polyester for the amount of monomers present in the repeat units and for determining the composition of copolymers and polymer blends. The relative standard deviation varies from 0.8% for the determination of 1,4-butanediol to approximately 2% for 1,4-cyclohexanedimethanol. For the determination of different concentrations of isophthalic acid, the standard deviation varies from 0.7 to 2.4%. 

High molecular weight linear polyesters from 1,4-butanediol (H0-(CH2 40H) and terephthalic acid (para- (COOH)2) are successful engineering plastics. They are not used as a blister (see-through) packaging material, however. A polymer for the blister-packaging market is made from the two monomers above plus isophthalic acid (meta- (COOH)2). Explain the difference in applications. 

However, side reactions, such as formation of ether groups or cychzation, were not investigated. Turner et al. [11] reported on the Bu2Sn(OAc)2-catalyzed polycondensation of 5-(2 -hydroxyethoxy) isophthalic acid in bulk at 190 °C. Dimethyl isophthalate served as core monomer in several experiments. Polycondensation promoted by bis(cyclohexyl)carbodiimide (DCC) were reported for the aromatic monomer (f), Formula 11.1 [35]. The mild reaction conditions prevented transesterification, but only low molar mass polyesters (Mw < 17 kDa) were obtained. Similar molar masses were achieved by Voit et al. [36] for carbodiimide promoted polycondensations of the triazene monomers (b) and (c), Formula 11.4. Somewhat more successful were DCC-activated polycondensations of trifunctional oligo(e-caprolactone)s such as (d), Formula 11.4, reported by Hedrick et al. [37, 38]. Syntheses of LC polyesters from monomers (e), Formula 11.4, and isomers were achieved by means of thionyl chloride and pyridine [39]. 

It must finally be kept in mind that it is extremely easy to adjust the properties of polyesters to desired values by adding small quantities (usually less than 10%) of comonomers in starting monomer feed. Isophthalic, adipic, dodecanedioic, p-hydroxybenzoic acids or esters and diethylene glycol, cyclohexanedimethanol, or bisphenol-A are often used for this purpose. Examples of property adjustment are the modification of solvent diffusivity of PET membranes by the addition of low levels of isophthalate or naphthalene dicarboxylate units in polymer chains139... 

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