Block copolymers of poly(L-lactide) and poly(ε-caprolactone) or poly(ethylene glycol) prepared by reactive extrusion

Stevels, W.M. and Bernard, A. and Witte van de, P. and Dijkstra, P.J. and Feijen, J. (1996) Block copolymers of poly(L-lactide) and poly(ε-caprolactone) or poly(ethylene glycol) prepared by reactive extrusion. Journal of Applied Polymer Science, 62 (8). pp. 1295-1301. ISSN 0021-8995

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Abstract:	Blends of poly(L-lactide) (PLLA) and poly(-caprolactone) (PCL) were prepared in a co-rotating twin screw miniextruder (40 rpm, 200°). It was attempted to prepare multiblock copolymers by allowing a controlled number of transesterification reactions. Various cat-alysts (n-Bu3SnOMe, Sn(Oct)2, Ti(OBu)4, Y(Oct)3, para-toluene sulphonic acid) were introduced to promote these transesterification reactions. However, PLLA degradation by ring-closing depolymerization was the dominant reaction in every case. Alternatively, after showing that L-lactide can be conveniently polymerized in the extruder, L-lactide and hy-droxyl functionalized prepolymers of PCL or poly(ethylene glycol) (PEG) were fed to the extruder in the presence of stannous octoate. Monomer conversions of over 90% and effective transformation of all hydroxyl end groups present were generally reached. Di-and triblock copolymers could be prepared in this way with characteristics very similar to polymers prepared in a batch-type process, but with considerably reduced reaction times in a fashion, which is, in principle, scaleable to a continuous process for the production of such block copolymers.
Item Type:	Article
Copyright:	© 1996 Wiley InterScience
Faculty:	Science and Technology (TNW)
Research Group:	Polymer Chemistry and BioMaterials (PBM)
Link to this item:	http://purl.utwente.nl/publications/71284
Official URL:	http://dx.doi.org/10.1002/(SICI)1097-4628(19961121)62:8<1295::AID-APP20>3.0.CO;2-5
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