Transesterification of poly(lactic acid) and poly(ethylene-co-vinylalcohol) was realized in-melt using different catalysts. Reactions were first conducted in an internal mixer and the different reaction parameters effect on exchange reactions and the obtained copolymers were optimized. Among the used catalysts, 1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) and Tin(II) bis(2-ethylhexanoate) (Sn(Oct)(2)) were particularly efficient. In a second part, reactions were made by reactive extrusion. In most of reaction conditions, compatible blends were obtained with a fine micro phase separation. Only under extreme reaction conditions, high temperature and intensive mixing, nanostructured graft copolymers were obtained. (C) 2013 Elsevier B.V. All rights reserved.