Poly braided

Probably most of these investigators were studying poly(dichlorophosphazene) in the partially crosslinked state. Most of this was summarized by Allcock (.9). More recently, highly purified, uncrosslinked II has been examined in the solid state (21). The unstressed polymer is amorphous at room temperature, but crystallization can be induced by cooling or stretching techniques. The glass transition temperature, measured by Torsional Braid Analysis, is -66°C (22). 

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. 

The same annealed braids were also subjected to in vivo BSR testing. The results are shown in Figure 1 for both the poly(L-lactide) and 95/5 poly(L-lactide-co-glycolide). These data showed that during the first 4-5 months, both sutures retained... 

Table 1. Tensile Properties of Braided Poly(Lrlactide) and 95/5 Poly(Hactice-co-glycolide) Yams...

Table 2. In Vitro BSR (pH 7.27 buffer, 50 C) of Poly(i lactide) and 95/5 Poly(L-lactide-co-glycolide) Braids...

BENICEWICZETAL. Poly(L-lactide) Braided Filament Yams... 

Torsional braid analysis indicates that the —Si—O—Si— flexible chain is present and persists, although its flexibility is somewhat impaired, even when the material is fully cured. This indicates that there is a substantial proportion of the R—Si—O— units which are neither crosslinked nor involved in ring formation. However, a spiral structure with the hydroxyl groups enclosed along the core meets the requirements. Such a structure has been suggested by Birchall et al. [12] for silanol-terminated poly(oxymethylenes). 

Figure 3. A comparison between the mechanical properties of poly(sty-rene) and a poly(styrene) braid. ( ) Compression-molded sample of PS.

The value of the modulus of the poly (styrene) braid at low temperature is smaller than the sample of pure poly (styrene) because the cross-section of the braid is rather irregular, and the approximation of an irregular cross-section by a circular one will inevitably lead to an underestimate of modulus (21). For this reason, the absolute values of the modulus of the multiblock polymers in Figures 4-10 are unreliable. 

Hu W, Huang ZM (2010) Biocompatibility of braided poly(L-lactic acid) nanofiber wires applied as tissue sutures. Polym Int 59(1 ) 92—99... 

Such TTT diagrams have also been useful in describing the cure of polyimide systems, as shown in Palmese (1987), which shows the TTT diagram of a polyamicacid/polyimide system. The TTT diagram of a polycyanurate system is developed by Simon (1993) on the basis of FT-IR, DSC and torsional braid measurements. Kim et al (1993) developed a TTT diagram for a thermoset-thermoplastic blend, specifically a tetrafunctional epoxy-resin/poly(ether sulfone)/dicyandiamide thermoset-thermoplastic blend (Figure 2.9). 

The first synthetic absorbable suture was made from a homopolymer of glycolic acid by Davis Geek Co. and manufactured with the tradename Dexon (1970). This suture was followed by a second material produced by Ethicon, Inc., in 1974, a copolymer of lactide and glycolide known as poly-glactine 910 or Vicryl. Both Vicryl and Dexon are made from polymer fibers, which are braided to produce sutures. In addition. Vicryl is Teflon coated for... 

Benicewicz, B. C., Shalaby S. W., Clemow, A. J. and Oser, Z., In vitro and in vivo degradation of poly(Z-lactide) braided multifilament yams, in Agriculture and Synthetic Polymers, Glass, J. E. and Swift, G., Eds., American Chemical Society, Washington, DC, 1990, chap. 14. 

Tensile and in vitro and breaking strength retention data of typical monofilament sutures made of the polymers described in Section 8.3.2 are summarized in Table 8.6. The data in Table 8.6 indicate that the polymers described in Table 8.5 can be converted to monofilament sutures with competitive strength retention and breaking strength profiles as the commercially available braided sutures made of polyglycolide or 90/10 poly(glycolide-co-/-lactide). 

Sutures remain the most common method of tpproximating the divided edges of tissue (1). Sutures are categorised by size, material, design and behaviour. Absorbable and nonabsorbable materials are further divided into synthetic versus natural products, some of vdiich can be fabricated in braided and/or monofilament form. Non-absorbable sutures have played an important role in the development of surgical procedures, generally made of silk, polyamide, polyester, polypropylene, polyethylene and poly(tetrafluoroethylene) (2). 

Poly(glycolide/L-lactide) copolymer at 90% glycolide and 10% L-lactide Polyglactin 910 Coated vicryl Braided or monofilament... 

Bajaj, M. S., Sastry, S. S., Ghose, S., Betharia, S. M. and Pushker, N. (2004). Evaluation of polytetrafluoroethylene sutirre for frontahs suspension as compared to poly-butylate-coated braided polyester. Clinical and Experimental Opthalmology, 32, 415-419. 

Poly(glycolide/L-lactide) Coated Vicryl Braided or... 

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