Alkylene polyesters

Alternative technology for modifying a poly(aLkylene terephthalate) by incorporation of a phosphinate stmcture has been developed by Enichem. Phosphinate units of the stmcture —P(CgH5) (0)CH20— are introduced into a polyester such as PET or PBT by transesterification with an oligomer comprised of the aforementioned units (136). 

Manufacture. The manufacture of 1,4-cyclohexanedimethanol can be accompHshed by the catalytic reduction under pressure of dimethyl terephthalate ia a methanol solution (47,65). This glycol also may be prepared by the depolymerization and catalytic reduction of linear polyesters that have alkylene terephthalates as primary constituents. Poly(ethylene terephthalate) may be hydrogenated ia the presence of methanol under pressure and heat to give good yields of the glycol (see Polyesters) (66,67). 

With all six series of polyester illustrated in Figure 25.14, as the number of methylene groups in the repeating unit increases so the polymer becomes more like a linear polyethylene (polymethylene). Thus the melting points for five of the six classes are seen to converge towards that of the melting point of polymethylene. In the ca.se of the sixth class, the poly(alkylene adipates), there would appear no reason to believe that additional data on other specific members of the class would not lead to a similar conclusion. 

In the poly(alkylene arylate) series, Tm decreases with increasing length of flexible — (CH2) — moieties and, as in the aliphatic series, approaches the limiting value of polyethylene melting point for large n values (Table 2.6). Aromatic -aliphatic polyesters with even numbers of methylene groups melt at higher... 

Hie reaction of dicarboxylic acid cesium or potassium salts with alkylene dihalides is another method of polyester preparation in relatively mild conditions... 

Siloxane containing polyester, poly(alkylene oxide) and polystyrene type copolymers have been used to improve the heat resistance, lubricity and flow properties of epoxy resin powder coatings 43). Thermally stable polyester-polysiloxane segmented copolymers have been shown to improve the flow, antifriction properties and scratch resistance of acrylic based auto repair lacquers 408). Organohydroxy-terminated siloxanes are also effective internal mold release agents in polyurethane reaction injection molding processes 409). 

The DuPont patent (US 5866622 A, 1999) describes dissolving the polyester in molten dimethylterephthalate, methyl-/ -toluate or dimethylisophthalate and separating the polyester from non-polyester components. The polyester can subsequently be used as a feedstock for methanolysis to form dimethylterephthalate (DMT) and alkylene glycol. The DMT can be subsequently hydrolysed to recover terephthalic acid. 

Two-step synthesis of sugar-containing polyesters by lipase CA catalyst was reported (Scheme 13)." Lipase CA catalyzed the condensation of sucrose with an excess of divinyl adipate to produce sucrose 6,6 -O-divinyl adipate, which was reacted with a,oo-alkylene diols by the same catalyst, yielding polyesters containing a sucrose unit in the main chain. This method conveniently affords... 

Galbis et al. described a variety of carbohydrate-based linear polyesters 61 of the poly(alkylene dicarboxylate) type that were obtained by polycondensation reactions of the alditols 2,3,4-tri-(9-methyl-L-arabinitol (9) and 2,3,4-tri-O-methyl-xylitol (10), and the aldaric acids 2,3,4-tri-(9-methyl-L-arabinaric acid (26) and 2,3,4-tri-(9-methyl-xylaric acid (27), butanediol, and adipic acid were also used as comonomers [28]. Copolyesters of the poly(aIkylene-c )-arylene dicarboxylate) type were obtained using bisphenols as comonomers (Scheme 1). Chemical polycondensation reactions were conducted in bulk or in solution. Enzymatic polycondensation reactions of adipic acid with the above-mentioned alditols were carried out successfully using Lipozyme and Novozyme 435. The hydrolytic degradations of some of these polyesters were also described. 

Polyethers and polyesters having methoxybenzalazine units with various alkylene groups (C4, C6 and Cg) in the main chain were synthesized from vanillin (7,8). The condensation reaction of 4,4 -alkylenedioxybis (3-methoxybenzaldehyde) [VI] with hydrazine monohydrate was applied to the synthesis of polyethers [VII] (Mn, 7.4 x 103 for C4, 7.3 x 103 for C6 and 4.1 x 103 for Cg derivatives), as shown in Scheme 3. Polyesters [IX] (77jnh, 0.35 dl/g for C4, 0.38 dl/g for C6 and 0.43 dl/g for Cg derivatives) were synthesized from 4,4 -dihydroxy-3,3 -dimethoxybenzalazine [VIII] and di-carboxylic acid chlorides by conventional low temperature solution polycondensation, as shown in Scheme 4. 

The thermal stability of the samples was studied by TG. As shown in Table I, the decomposition temperatures (Tchain length of the alkylene groups in both the polyethers and polyesters. 

Table I. Starting temperatures of decomposition (T

Various furan compounds have been incorporated into a polyester fiber to provide electrostatic resistance toward antistatic fabrics <1999KRP160475>. Up to 1 wt.% of the furan compound was combined together with a polyoxy-alkylene glycol compound and a nonreactive lithium alkylsulfonate to copolymerize the polyester. Upon drying, melt spinning, and stretching, the formed polyester fibers showed excellent electrostatic resistance. 

C. McNeill and M. Bounekhel Thermal degradation studies of terephthalate polyesters 1. Poly(alkylene terephthalates), Polym. Degrad. Stab., 34, 187-204 (1991). 

Esterification and transesterification were used for the synthesis of numerous polymeric stabilizers derived from carboxylic as well as inorganic acids. Systems obtained with poly(alkylene ether)diols contain polyether and polyester links. 

Polyesters have been synthesized by the reaction of glycols with the diammonium or bis(triethylammonium) salts or fV-methylpyrrolidone complexes of dibasic acids. Dicarboxamides or dinitriles also react with glycols to form polyesters. Alkylene halides and salts of terephthalic acid react to give polyesters. In general, however, all these reactions give low-molecular-weight products, and no kinetic studies have been made. 

Our cooperation with Sheats also extended into the area of condensation polymers of cobalticinum salts.92 Ionic polyesters were prepared by melt-phase transesterification of 1,1 bis(carbethoxy)cobalticinium hexafluorophosphate with various diols. Low molecular-weight polysters were formed. However, attempts to prepare polyamides by melt condensations of alkylene diammonium salts of l,l -bis(carboxy)cobalticinium PFg salts resulted in decomposition.92... 

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