Tetramethylene terephthalate copolymers

Figure 9 shows the dynamic mechanical spectra of a series of poly-(tetramethylene oxide) /poly (tetramethylene terephthalate) (PTMO/ PTMT) segmented copolymers (67). These materials reveal only one Tg and one Tm analogous to semicrystalline thermoplastics. The magnitude of both transition temperatures shifts progressively higher with increasing... 

Studies have been conducted on poly (tetramethylene oxide )-poly-(tetramethylene terephthalate) -segmented copolymers that are identical in all respects except for their crystalline superstructure (66,67,68). Four types of structures—type I, II, and III spherulites (with their major optical axis at an angle of 45°, 90°, and 0° to the radial direction, respectively), and no spherulitic structure—were produced in one segmented polymer by varying the sample-preparation method. Figures 10 and 11 show the stress-strain and IR dichroism results for these samples, respec-... 

T nterest in polyether-ester block copolymers that are both thermoplastic - and elastomeric continues at a sustained pace (1-9). Most of the recent communications have dealt with the tetramethylene terephthalate/ poly(tetramethylene ether) terephthalate copolymers which are continuing to find increased use in commercial applications requiring thermoplastic elastomers with superior properties. 

Part I of this series explored the structure-property relationships of tetramethylene terephthalate/polyether terephthalate copolymers as a function of variations in the chemical structure, molecular weight, and concentration of the polyether units (10). Of the polyether monomers tested, poly (tetramethylene ether) glycol of molecular weight approximately 1000 was found to provide copolymers having the best overall combination of physical properties and ease of synthesis. 

Copolymer compositions are expressed as weight percentages of the ester units with the remainder being polyether-ester units. For instance, 40% tetramethylene terephthalate/PTME terephthalate copolymer represents a block copolymer containing 40 wt % of tetramethylene terephthalate units and by difference 60 wt % of poly(tetramethylene ether) terephthalate units. 

Polymer compositions are based on the ratios of starting monomers on the assumption of no loss of monomers during copolymerization other than the deliberate removal of the excess diol needed to drive the copolymerization to completion. The polymerization procedures are believed to result in block copolymers composed of a random distribution of components (12,13). The block structures of these copolymers are attributed to the use of PTME glycol as one of the monomers. X-ray diffraction studies of tetramethylene terephthalate/PTME terephthalate copolymers have verified the presence of crystalline tetramethylene terephthalate segments and the apparent lack of crystallinity of the PTME terephthalate segments (14). 

The concentration of crystalline ester segments in tetramethylene terephthalate/PTME terephthalate copolymers has a major effect on physical properties. Copolymers were prepared and tested which covered a range of tetramethylene terephthalate (4GT) concentrations from a low of 30% to a high of 82% (Table I). 

Table I. Tetramethylene Terephthalate/PTME Terephthalate Copolymers—Properties as a Function of Tetramethylene Terephthalate Content (36)...

The structure of the diol in alkylene terephthalate/PTME terephthalate copolymers has an important effect on the properties of these block copolymers, as evident from the results shown in Tables II, III, and IV. The 50% tetramethylene terephthalate/PTME terephthalate copolymer prepared from 1,4-butanediol (4G) which was previously noted in Table I serves as our reference copolymer for purposes of discussing the effects of changing the structure of the crystallizable ester segments. The outstanding properties of the 4G-based copolymer are ease of synthesis, a rapid rate of crystallization from the melt, a high melting point, and excellent tensile and tear strengths. 

Figure 2. Permanent set at break as a percentage of elongation at break vs. the wt % of tetramethylene terephthalate segments in tetramethylene terephthalate/PTME terephthalate copolymers (36)...

Up to this point the discussion has been concerned with alkylene terephthalate/PTME terephthalate copolymers in which the concentration of alkylene terephthalate and the chemical structure of the alkylene groups have been varied. The next section of this report is concerned with polyether-ester copolymers in which aromatic esters other than terephthalate are used in combination with PTME glycol and various diols. The objective is the same, to correlate changes in copolymer structure with changes in copolymerization results and copolymer properties. Once again the 50% tetramethylene terephthalate/PTME terephthalate copolymer (Tables I and II) with its excellent properties and relative ease of synthesis will be used as the point of reference to which the other polymers will be compared. 

These effects are not unique to copolymers in the isophthalate/ terephthalate system but are the expected results of copolymerizing the crystallizable tetramethylene terephthalate hard segment with any relatively lower-melting short-chain diol ester segment. The apparent eutectic at a 4GT mole fraction of 0.25 represents the condition where there are few short-chain diol ester segments present of either type having sufficient length to crystallize. 

Nagata, M., Goto, H., Sakai, W. and Tsutsumi, N. (2000) Synthesis and enzymatic degradation of poly(tetramethylene succinate) copolymers with terephthalic acid. Polymer, 41 (11), 4373-4376. 

Polyarylate resin Polyarylether ketone resin Polyester carbonate resin Polyetherimide resin Polyethylene, chlorinated Polyethylene glycol Polyethylene, medium density Poly (p-methylstyrene) Poly (p-methylstyrene), rubber-modified Poly (oxy-1,2-ethanediyloxycarbonyl-2,6-naphthalenediylcarbonyl) resin Poly (oxy-p-phenylenesulfonyl-p-phenyleneoxy-p-phenyleneisopropylidene-p-phenylene) resin Poly (phenyleneterephthalamide) resin Polysulfone resin Poly (tetramethylene terephthalate) Polyvinylidene chloride Potassium sorbate Potato (Solanum tuberosum) starch Silica, colloidal Silicone Sodium N-alkylbenzenesulfonate Sodium bicarbonate Sodium tetraborate pentahydrate Starch, pregelatinized Styrene/acrylates copolymer Styrene/butadiene polymer Styrene/DVB copolymer , 1,1 -Sulfonylbis (4-chlorobenzene) polymer with 4,4 -(1-methylethylidene) bis (phenol) and 4,4 -sulfonylbis (phenol) Synthetic wax Tapioca starch Tetrafluoroethylene/perfluoro (propyl vinyl ether) copolymer Tocopherol Triglycidyl isocyanurate VA/crotonates copolymer Vinyl chloride/ethylene copolymer Wheat (Triticum vulgare) starch... 

Isophthaloyl chloride has also been employed in block copolymer preparation. Poly(m-phenylene isophthalamide) and either poly-(ethylene oxide) or poly(dimethyl siloxane) block copol3miers have been prepared by terminating the former with isophthaloyl chloride and subsequently adding hydroxy terminated poly(ethylene oxide) or poly(dimethyl siloxane)(79). Block copolymers were also produced when a polyformal was capped with 1,6-hexandiol, and then heated in the presence of poly(tetramethylene terephthalate)(80). In another interesting application, polyesterpolyether block copolymers of poly-(ethylene terephthalate) and a number of polyglycols have been reported(Sl). Their synthesis involves esterification, catalyzed by zinc acetate/titanyl oxalate. ABA block polymer of 2-hydroxyethyl methacrylate and styrene was prepared by coupling -NH2 terminated PHEMA and isocyanate terminated polystyrene. The latter material was prepared by UV polymerization of styrene in the presence of bis(p-isocyanatophenyl)disulfide (82),... 

Ester Single Tg II was Hytrel 5556, a multiblock copolymer with poly(tetramethylene ether) glycol terephthalate soft segment and tetramethylene terephthalate hard segment Gaztelumendi et al. (1988)... 

The preparation of tetramethylene terephthalate-tetramethylene sebacate copolymers has been detailed together with their characterizations. ... 

Copolyester Systems.— The synthesis of modified ether-type polyesters and their applications have been reviewed. Block copolymer systems based on poly-(hexamethylene sebacate)-poly(dimethylsiloxane) have been synthesized and characterized by n.m.r. and crystallization studies. Tetramethylene sebacate-tetramethylene terephthalate random copolymers have been prepared and... 

Crystallizable Block Copolymer Morphologies While the largest part of the block copolymer literature describes totally amorphous materials, one or more of the blocks may form semicrystalline regions. Examples include polyester-polyether block copolymers (39), where the poly(tetramethylene terephthalate) polyester blocks crystallize, and the thermoplastic polyurethane elastomers, where the polyurethane hard blocks crystallize (40). 

Saint-Loup, R., R. Jean-Jacques, and B. Boutevin, Synthesis of Polyfethylene terephthalate)-block-Poly(tetramethylene oxide) Copolymer by Direct Poly esterification of Reactive Oligomers. Macromolecular Chemistry and Physics,... 

Fig. 4.16. The dependence of the melting temperature on the average block length of tetramethylene terephthalate in its copolymer with poly(oxytetramethylene glycol). From [74],...

Lembicz F and Slonecki J (1991) Thermomechanical properties of poly(l,2-oxyprop-ylene)-poly(tetramethylene terephthalate) block copolymers, Kaut Gummi Kunstst 44 668-670. 

Nagata M, Kiyotsukuri T, Minami S, Tsutsumi N and Sakai W (1996) Biodegradability of poly(ethylene terephthalate) copolymers with poly(ethylene glycol)s and poly(tetramethylene glycol), Polym Int 39 83-89. 

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