Poly p-Dioxanone PDO

Poly(p-dioxanone) (PDO) is a well-known aliphatic polyester it is prepared by ROP of p-dioxanone, and shows good physical properties (Scheme 2.5). It is semicrystalhne, with a low glass-transition temperature in the range —10 to 0°C. The properties of PDO with different molecular weights have been investigated [363]. Molecular weight has a positive influence on the thermal stability of PDO. PDO has ester bonds in the polymer chains, which play a crucial role in its biodegradation [368]. 

Like poly(p-dioxanone) homopolymer, copolymers of PDO and lactide can be prepared by several conventional polymerization means. The most commercially viable method relies upon melt polymerization. Since a thermodynamic equilibrium between the monomer (p-dioxanone) and the polymer [poly (p-dioxanone) ], results during polymerization (Bezwada et al, 1987, 1990) in conversions ranging from... 

Segmented copolymers of p-dioxanone/glycolide (Bezwada, Shalaby and Newman, 1987) can be prepared by a similar method as segmented copohnners of p-dioxanone/L(-)lactide. Firstly, p-dioxanone (PDO) monomer is melt pohnner-ized to produce a mixture of poly(p-dioxanone) homopolymer and pedioxanone monomer. 

The microwave-assisted ring-opening polymerization of poly(p-dioxanone) (PPDO) from the monomer p-dioxanone (PDO) was observed by Li et al. (2006), with constant microwave power (90, 180, 270 and 360 W) and temperature maintained at 158 to 198°C. The polymerization at 270 W for 25 min using Sn(Oct)j as a catalyst gave 63% yield of PPDO with a viscosity-average molecular weight (Mv) of 156,000 g/mol. It was observed that time for polymerization was 14 h in conventional polymerization method. 

PDO = poly-1,4-dioxane-2-one PGA = polyglycolic acid PTMC = polytrimethylene-carbonate PCL = polycaprolactone PGL = poly(glycolid-lactide) PG = polyglycolide PDS = p-dioxanone PTMT = polytetramethylene terephthalate i-P = isotactice polypropylene PLG = poly(lactide-glycolide). Source Ingle (2003) Chu etal. (1997). 

Purac Biochem. The plating systems are formed from a polymer blend comprising a 50 50 mole mole poly(D,L-lactide) (referred to as D,L-PLA) and a 95 5 mole mole poly(e-caprolactone-co-p-dioxanone) (referred to as 95 5 PCL PDO). The D,L-PLA was also obtained from Purac Biochem. 

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