2-ethylhexanoic acid tin(II) salt → Poliglecaprone

Participants

Reaction Conditions

Reaction Steps

A flame dried 500 ml single-neck round-bottom flask is charged with 79.90 gm. (0.70 mole) of ε-caprolactone, 150.89 gm (1.30 mole) of glycolide, 0.228 ml (1.20 mmole/mole of total monomer) of distilled diethylene glycol and 0.135 ml stannous octoate (0.33 molar solution in toluene). The flask is fitted with a flame dried mechanical stirrer and appropriate adapters to provide a closed system. The reactor is purged three times before being vented with nitrogen. The reaction mixture is heated to 190° C. under nitrogen, and maintained at this temperature for about 16 to 18 hours. The copolymer is isolated, ground, and devolatilized (42 hours/110° C./0.1 mm Hg) to remove any unreacted monomers. A weight loss of 4.8% is observed upon devolatilization. The inherent viscosity (I.V.) of the copolymer is 1.46 dl/g in hexafluoroisoproponal (HFIP) at 25° C. The molar ratio of PCL/PGA is found to be 32.2/67.8 by NMR. The glass transition temperatures (Tg) and the melting point (Tm) of this copolymer are found to be 7° C./58° C. and 133° C., respectively, by DSC.

Provenance & Evidence