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Chitosan and N ‐carboxymethylchitosan: I. The role of N ‐carboxymethylation of chitosan in the thermal stability and dynamic mechanical properties of its films
Author(s) -
Miranda Maria Enoi Santos,
Marcolla Catiana,
Rodrígues Clóvis Antonio,
Wilhelm Helena Maria,
Sierakowski Maria Rita,
Bresolin Tania Mari Bellé,
de Freitas Rilton Alves
Publication year - 2006
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.2060
Subject(s) - chitosan , thermogravimetric analysis , thermal stability , scanning electron microscope , materials science , thermal analysis , polymer chemistry , dynamic mechanical analysis , composite material , polymer , nuclear chemistry , chemistry , thermal , organic chemistry , physics , meteorology
Chitosan (degree of deacetylation of 90.2%) and N ‐carboxymethylchitosan ( N ‐CMCh) (degree of substitution of 18.5%) were analyzed using thermogravimetric analysis in order to determine their thermal stability. Also, their films were evaluated using scanning electron microscopy (SEM) and mechanical and dynamic mechanical analysis (DMA). Both polymers showed a thermal degradation peak at T m ∼ 250 °C, with T onset and weight loss of 175 °C and 62% and 190 °C and 35% for chitosan and N ‐CMCh, respectively. N ‐CMCh showed a second thermal degradation peak at T m = 600 °C, with an additional weight loss of 25%. Kinetic thermal analysis showed a slower process of degradation at 100 °C for N ‐CMCh compared with chitosan, and an activation energy 13 times higher for the former, confirming the higher stability of N ‐CMCh. Analysis of chitosan and N ‐CMCh films showed that the latter support a high tension, with lower elasticity, and, as revealed by DMA, N ‐CMCh has a more compact film structure, with a crossing arrangement of N ‐CMCh fibers, as compared with the chitosan films which were determined from SEM analysis to have fibers in one direction only. Copyright © 2006 Society of Chemical Industry