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Subject: Bio-based ×

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Now showing 1 - 3 of 3
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    Scalable synthesis and polymerisation of a β-angelica lactone derived monomer
    (Cambridge : RSC, 2020) Dell'Acqua, Andrea; Stadler, Bernhard M.; Kirchhecker, Sarah; Tin, Sergey; de Vries, Johannes G.
    Bio-based levulinic acid is easily ring-closed to α-angelica lactone (α-AL). α-AL can be isomerized to the conjugated β-AL under the influence of base, but since this is an equilibrium mixture it is very hard to devise a scalable process that would give pure β-AL. This problem was circumvented by distilling the equilibrium mixture to obtain a 90 : 10 mixture of β-and α-AL in 88% yield. This mixture was used for Diels-Alder reactions on 3 terpenes and on cyclopentadiene in up to 100 g scale. The latter DA adduct was subjected to a ROMP reaction catalysed by the Grubbs II catalyst. The resulting polymer has some similarities to poly-norbornene but is more polar. The polymer can be processed into films with very good transparency. © The Royal Society of Chemistry.
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    Synthesis and Characterization of Methyl Cellulose/Keratin Hydrolysate Composite Membranes
    (Basel : MDPI, 2017) Liebeck, Bernd M.; Hidalgo, Natalia; Roth, Georg; Popescu, Crisan; Böker, Alexander
    It is known that aqueous keratin hydrolysate solutions can be produced from feathers using superheated water as solvent. This method is optimized in this study by varying the time and temperature of the heat treatment in order to obtain a high solute content in the solution. With the dissolved polypeptides, films are produced using methyl cellulose as supporting material. Thereby, novel composite membranes are produced from bio-waste. It is expected that these materials exhibit both protein and polysaccharide properties. The influence of the embedded keratin hydrolysates on the methyl cellulose structure is investigated using Fourier transform infrared spectroscopy (FTIR) and wide angle X-ray diffraction (WAXD). Adsorption peaks of both components are present in the spectra of the membranes, while the X-ray analysis shows that the polypeptides are incorporated into the semi-crystalline methyl cellulose structure. This behavior significantly influences the mechanical properties of the composite films as is shown by tensile tests. Since further processing steps, e.g., crosslinking, may involve a heat treatment, thermogravimetric analysis (TGA) is applied to obtain information on the thermal stability of the composite materials.
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    Renewable vanillin based flame retardant for poly(lactic acid): A way to enhance flame retardancy and toughness simultaneously
    (London : RSC Publishing, 2018) Zhao, Pengcheng; Liu, Zhiqi; Wang, Xueyi; Pan, Ye-Tang; Kuehnert, Ines; Gehde, Michael; Wang, De-Yi; Leuteritz, Andreas
    In this study, a novel bio-based flame retardant material consisting of modified vanillin and poly(lactic acid) (PLA) was developed by incorporation of newly discovered additive, bis(5-formyl-2-methoxyphenyl) phenylphosphonate (VP), into the PLA matrix. The chemical structure of VP was confirmed by 1 H-, 13 C- and 31 P NMR and FTIR. The flame retardancy, thermal behavior as well as the mechanical properties of PLA/VP composites were evaluated. With 5 wt% of VP, the LOI of PLA increased from 21.4 to 25.8 and passed the UL-94 V-0 classification. Additionally, the elongation at break was improved from 3% to 11% without sacrificing tensile strength. In an effort to understand the mechanisms, TGA-FTIR, TGA and SEM were performed. This paper suggests a new possibility to prepare polymeric composites with enhanced flame retardancy from sustainable resources.