Poly trimethylene

In order to achieve the desired fiber properties, the two monomers were copolymerized so the final product was a block copolymer of the ABA type, where A was pure polyglycoHde and B, a random copolymer of mostly poly (trimethylene carbonate). The selected composition was about 30—40% poly (trimethylene carbonate). This suture reportedly has exceUent flexibiHty and superior in vivo tensile strength retention compared to polyglycoHde. It has been absorbed without adverse reaction ia about seven months (43). MetaboHsm studies show that the route of excretion for the trimethylene carbonate moiety is somewhat different from the glycolate moiety. Most of the glycolate is excreted by urine whereas most of the carbonate is excreted by expired CO2 and uriae. 

Although poly(trimethylene terephthalate) has been known for many years it was only introduced by Shell in the late 1990s as a consequence of a breakthrough in the synthesis of the monomer 1,3-propane diol which enabled the polymer to be produced at costs suitable for commercialisation. The polymer itself is prepared by melt condensation of the diol with terephthalic acid. 

TABLE 2.11 Typical Properties of Unfilled Polyethylene terephthalate) (PET), Poly(trimethylene terephthalate) (PTT), and Poly(butylene terephthalate (PBT) Solid-State Polyester Resins... 

H. H. Chuah, Corterra Poly (trimethylene) terephthalate — New Polymeric Fiber for Carpets, Paper presented at Tifcon 96, Blackpool, U.K. (1966). http //www. shellchemicals.com. 

Journal of Applied Polymer Science 82, No. 1, 3rd October 2001, p.99-107 ALKALINE DEPOLYMERISATION OF POLY(TRIMETHYLENE TEREPHTHALATE)... 

SCHEME 8.7 Synthesis of statistical poly(trimethylene carbonate-co-caprolactone). 

Poly(trimethylene terephthalate) (PTT) is a polymer with very useful properties. As a textile fibre it has excellent softness, stretch and recovery. As a resin it has excellent barrier properties. Developed over 60 years ago, PTT has not been very widely used compared to poly(ethylene terephthalate) (PET) as one of the key monomers 1,3-propanediol (PDO) has been expensive. 

Meanwhile Ethicon (and others) developed alternative absorbable surgical sutures, based, for example, on copolymers of polyglycolide with poly-L-lactide or poly(trimethylene carbonate), and on polydioxanone, and on poly(e-oxycaproate), and also on copolymers of these with polyglycolide or with each other. These different structures made it possible to provide fibres with different rates of absorption, with different degrees of stiffness or flexibility, and for use in monofilaments, braided multifilaments, and other yam structures, as required for different surgical operations. 

Synthesis, Properties and Applications of Poly(Trimethylene Terephthalate)... 

Poly(trimethylene terephthalate) (PTT) is a newly commercialized aromatic polyester. Although available in commercial quantities only as recently as 1998 [1], it was one of the three high-melting-point aromatic polyesters first synthesized by Whinfield and Dickson [2] nearly 60 years ago. Two of these polyesters, polyethylene terephthalate) (PET) and poly(butylene terephthalate) (PBT), have become well-established high-volume polymers. PTT has remained an obscure polymer until recent times because one of its monomers, 1,3-propanediol (PDO), was not readily available. PDO was sold as a small-volume fine chemical at more than 10/lb., and was therefore not suitable as a raw material for commercial polymers. 

Figure 11.1 The chemical structure of poly(trimethylene terephthalate)...

Figure 11.7 Experimental and calculated heat capacities of solid and liquid PTT [49], From Heat capacity of poly(trimethylene terephthalate), Pyda, M., Boiler, J., Grebowicz, J., Chuah, H., Lebedev, B. V. and Wunderlich, B., J. Polym. Sci., Polym. Phys. Ed., 36, 2499-2511 (1998), Copyright (1998 John Wiley Sons, Inc.). Reprinted by permission of John Wiley Sons, Inc...

Figure 11.14 Effect of applied strain on the 002 d-spacing of a PTT fiber drawn at 3.3 x measured by WAXD [76], Reprinted from Polymer, 42, Wu, J., Schultz, J. M., Samon, K. M., Pangelinan, A. B. and Chuah, H. H., In situ study of structure development in poly(trimethylene terephthalate) fibers during stretching by simultaneous synchrotron small- and wide-angle X-ray scattering, 7141-7151, Copyright (2001), with permission from Elsevier Science...

Figure 11.16 PTT WAXD pattern and indices of the reflections [45]. From Polym. Bull., Crystal orientation function of poly(trimethylene terephthalate) by wide-angle X-ray diffraction, Chuah, H. H. and Chang, B. T. A., 46, p. 310, Figure 2, Copyright Springer-Verlag (2001). Reproduced by permission of Springer-Verlag GmbH Co. KG...

Chuah et al. [107] prepared a series of PTT/poly(trimethylene napthalate) (PTN) copolyesters by copolymerizing PDO with dimethyl terephthalate and dimethyl naphthalate. The PTN homopolymer has a 7 g of 75 °C and a Tm of 245 °C. Despite the more rigid napthalate moiety, the PTN Tg and Tm were much lower than the Tg of poly(ethylene naphthalate) (PEN), indicating the strong influence of the flexible trimethylene units. 

---