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Title
Lignin blends with polyurethane-containing lactate segments. Properties and enzymatic degradation effects
Authors
L. Ignat M. Ignat E. Stoica C. Ciobanu and V. I. Popa
Received
November 17, 2010
Published
Volume 45 Issue 3-4 March-April
Keywords
lignin, polyurethane, blends, peroxidase, laccase, tensile strength, thermal decomposition
Abstract
A series of lignin-polyurethane blends were synthesized from biodegradable poly(ester-urethane) elastomers containing lactate segments and lignin (flax/soda pulping) by mixing their dimethylformamide solutions. The resulting films were subsequently treated with fungal peroxidase and laccase, to compare the degradative potential of these enzymes on the natural and synthetic blend components. Lignin addition was found to substantially improve the structural organization of polyurethanes and, hence, the mechanical properties of blends. Also, lignin determines a consistent reduction of mass loss during thermal decomposition, especially in the case of previously enzyme-treated samples. The attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectra showed that both lignin and polyurethane were affected by the oxidative enzymatic treatment, at least on film surface. Polyurethane degradation was mainly related to the chain scission of polyester and lactate segments, being strongly influenced by lignin addition and enzyme type, and accompanied by significant changes in the subsequent thermo-mechanical behavior.
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