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Influence of chain extenders on the melt strength and thermal stability of polyglycolic acid
Author(s) -
Chen Lanlan,
Sun Xiaojie,
Ren Yueqing,
Wang Rong,
Liang Wenbin,
Duan Xuelei
Publication year - 2021
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.50551
Subject(s) - materials science , glycidyl methacrylate , thermal stability , reactive extrusion , melt flow index , isocyanate , molding (decorative) , composite material , acrylonitrile , extrusion , polymer chemistry , copolymer , polymer , chemical engineering , polyurethane , engineering
Biodegradable polyglycolic acid (PGA) has been attracting much attention recently. However, poor melt strength and thermal stability limit the processing of PGA by methods such as film blowing and injection molding. To improve melt strength and thermal stability, two reactive chain extenders, styrene–acrylonitrile‐glycidyl methacrylate terpolymer (poly(St‐AN‐GMA)) and 4, 4′‐methylenebis(phenyl isocyanate) (MDI), were incorporated respectively into PGA using twin‐screw extrusion. MDI was found to be more effective in chain extension and enhancing thermal stability than poly(St‐AN‐GMA). The T ‐5% (the temperature where the remaining weight percentage is 95%) of PGA modified with 3 wt% MDI increased to 334.5°C from 310.8°C for pure PGA. Melt flow rate for the same materials decreased from 47.2 g/10 min to 13 g/10 min. The activation energy of thermal degradations for MDI‐modified PGA was twice that of the unmodified PGA as evaluated by the Flynn‐Wall‐Ozawa method.