Effects of high-lignin-loading on thermal, mechanical, and morphological properties of bioplastic composites
| Autor: | Volker Sieber, Doris Schieder, Ronja Scholz, Cordt Zollfrank, Frank Walther, Jörg Dörrstein, Dominik Schwarz |
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| Přispěvatelé: | Publica |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Materials science
02 engineering and technology Polyethylene 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences chemistry.chemical_compound Viscosity chemistry Natural rubber Rheology visual_art Volume fraction Ceramics and Composites visual_art.visual_art_medium Vinyl acetate Lignin Composite material 0210 nano-technology Glass transition Civil and Structural Engineering |
| Popis: | The present study investigates the effects of high-lignin-loading on properties of lignin/polyethylene-co-vinyl acetate (EVA) rubber composites. Results from mechanical (quasi-static and cyclic) and rheological investigations revealed a brittle-ductile transition around a lignin volume fraction of fL = 0.59 coinciding with a twofold increase in steady-shear viscosity. Towards higher lignin contents, a 36% increase in dynamic stiffness Cdyn from fL = 0.59 (Cdyn ≈ 350 N mm−1) to fL = 0.71 (Cdyn ≈ 550 N mm−1) was observed by load increase tests (LIT). In addition, analyses of the ultra-micro-hardness revealed less indentation creep towards high-lignin-loading. At fL = 0.59, a pronounced relaxation endotherm superimposed on the glass transition (Tg) was observed, which was ascribed to molecular confinement to occur at highly loaded composites. At this point, the molecular weight (Mw) of lignin increased considerably. These results were explained by the different role of lignin at high volume fraction, i.e. a change from lignin as mere stiffness-inducing filler to a strength-imparting and fatigue-resistant matrix component which was supported by morphological analysis. |
| Databáze: | OpenAIRE |
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