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Free radical branching of polylactide by reactive extrusion
Author(s) -
Carlson Denise,
Dubois Philippe,
Nie Li,
Narayan Ramani
Publication year - 1998
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.10192
Subject(s) - reactive extrusion , branching (polymer chemistry) , materials science , melt flow index , differential scanning calorimetry , extrusion , radical initiator , polymer , polymer chemistry , thermogravimetric analysis , gravimetric analysis , molar mass distribution , dynamic mechanical analysis , chemical engineering , composite material , copolymer , chemistry , organic chemistry , thermodynamics , physics , engineering
The reactive extrusion of polylactide (PLA) with a free radical initiator resulting in a branched polymer was accomplished. Reaction conditions were in the range of 160°C to 200°C with an initiator concentration between 0.0 and 0.5%. Triple detector size exclusion chromatography, melt flow index, thermal gravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis were used to characterize the polylactide polymers. PLA without initiator showed extensive degradation as was evidenced by a decrease in both molecular weight and melt viscosity. The optimum range for branching resulting in a high molecular weight and low melt flow index polylactide was found to be around 170°C to 180°C and 0.1 to 0.25% initiator.