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Apeldoorn, Netherlands

Jiang Y.,Technical University of Delft | Mikova G.,Polymer Technology Group Eindhoven BV | Kleerebezem R.,Technical University of Delft | van der Wielen L.A.M.,Technical University of Delft | Cuellar M.C.,Technical University of Delft
AMB Express | Year: 2015

This study focused on investigating the feasibility of purifying polyhydroxybutyrate (PHB) from mixed culture biomass by alkaline-based chemical treatment. The PHB-containing biomass was enriched on acetate under non-sterile conditions. Alkaline treatment (0.2 M NaOH) together with surfactant SDS (0.2 w/v% SDS) could reach 99% purity, with more than 90% recovery. The lost PHB could be mostly attributed to PHB hydrolysis during the alkaline treatment. PHB hydrolysis could be moderated by increasing the crystallinity of the PHB granules, for example, by biomass pretreatment (e.g. freezing or lyophilization) or by effective cell lysis (e.g. adjusting alkali concentration). The suitability of the purified PHB by alkaline treatment for polymer applications was evaluated by molecular weight and thermal stability. A solvent based purification method was also performed for comparison purposes. As result, PHB produced by mixed enriched cultures was found suitable for thermoplastic applications when purified by the solvent method. While the alkaline method resulted in purity, recovery yield and molecular weight comparable to values reported in literature for PHB produced by pure cultures, it was found unsuitable for thermoplastic applications. Given the potential low cost and favorable environmental impact of this method, it is expected that PHB purified by alkaline method may be suitable for other non-thermal polymer applications, and as a platform chemical. © 2015, Jiang et al.; licensee Springer. Source

Rietzler F.,Friedrich - Alexander - University, Erlangen - Nuremberg | Piermaier M.,Friedrich - Alexander - University, Erlangen - Nuremberg | Deyko A.,Polymer Technology Group Eindhoven BV | Steinruck H.-P.,Friedrich - Alexander - University, Erlangen - Nuremberg | Maier F.,Friedrich - Alexander - University, Erlangen - Nuremberg
Langmuir | Year: 2014

We introduce a new method for preparing ultrathin ionic liquid (IL) films on surfaces by means of electrospray ionization deposition (ESID) under ultraclean and well-defined ultra-high-vacuum (UHV) conditions. In contrast to physical vapor deposition (PVD) of ILs under UHV, ESID even allows deposition of ILs, which are prone to thermal decomposition. As proof of concept, we first investigated ultrathin [C8C1Im][Tf2N] (=1-methyl-3-octyl imidazolium bis(trifluoromethyl)imide) films on Au(111) by angle-resolved X-ray photoelectron spectroscopy (ARXPS). Films obtained by ESID are found to be virtually identical to films grown by standard PVD. Thereafter, ESID of [C8C1Im]Cl on Au(111) was studied as a first example of an IL that cannot be prepared as ultrathin film otherwise. [C 8C1Im]Cl forms a wetting layer with a checkerboard arrangement with the cationic imidazolium ring and the chloride anion adsorbed next to each other on the substrate and the alkyl chain pointing toward vacuum. This arrangement within the wetting layer is similar to that observed for [C8C1Im][Tf2N], albeit with a higher degree of order of the alkyl chains. Further deposition of [C8C 1Im]Cl leads to a pronounced island growth on top of the wetting layer, which is independently confirmed by ARXPS and atomic force microscopy. This behavior contrasts the growth behavior found for [C8C 1Im][Tf2N], where layer-by-layer growth on top of the wetting layer is observed. The dramatic difference between both ILs is attributed to differences in the cation-anion interactions and in the degree of order in the wetting layer of the two ILs. © 2014 American Chemical Society. Source

Harings J.A.W.,Polymer Technology Group Eindhoven BV | Harings J.A.W.,TU Eindhoven | Harings J.A.W.,Dutch Polymer Institute | Deshmukh Y.S.,TU Eindhoven | And 7 more authors.
Macromolecules | Year: 2012

In synthetic as well as natural polyamides, hydrogen bonding and conformations of amide motifs are strongly influenced by the presence of ions and their concentration, water molecules, and their structure, as well as the pH of the solution. This concept combined with solubility of synthetic aliphatic polyamides, in particular nylons, in water at elevated temperature and corresponding vapor pressure is evaluated as a new reversible shielding route in the processing of these polymers. So far, reversible shielding has not been feasible due to a lack in controlling desired activation and deactivation of hydrogen bonding at the judicious moments. Here we show that in the presence of large halogen anions, crystallization from the random coil state is suppressed by hydrophobic hydration, where the amorphous state of the fast crystallizing nylons can be maintained even at 20 °C. Small hydrating lithium cations are favored since they strengthen the hydrophobic nature of the anions. Complete deshielding of hydrogen bonding, after processing, is facilitated by simple migration of ions in water that allows recovery of the desired conformation and structure. © 2012 American Chemical Society. Source

Rajkumar V.A.,TU Eindhoven | Weijers C.,Polymer Technology Group Eindhoven BV | Debije M.G.,TU Eindhoven
Renewable Energy | Year: 2015

Polymer plates containing fluorescent dyes with photovoltaic cells attached to one or more edges have the potential to be used for solar light collection in the built environment. The heating of the polymer plates and the resulting effects this may have on the operating temperatures of the attached photovoltaic cells and the integrity of the cells are studied. The results indicate that the luminescent solar concentrator under a solar simulator will allow the edge attached photovoltaic cells to operate up to 10°C cooler compared to cells experiencing direct solar exposure because of the avoidance of infrared light. We also demonstrate the importance of correct adhesive to avoid rupture of the attached cell. © 2015 Elsevier Ltd. Source

Van Der Meulen I.,TU Eindhoven | Gubbels E.,TU Eindhoven | Huijser S.,TU Eindhoven | Sablong R.,Polymer Technology Group Eindhoven BV | And 4 more authors.
Macromolecules | Year: 2011

The catalytic ring-opening polymerization of macrolactones to polyethylene-like polyesters was investigated using aluminum-salen complexes as the initiators. Contrary to the common understanding that high molecular weights in these reactions can only be achieved by enzymatic ring-opening polymerization due to the absence of ring tension in macrolactones, the aluminum-salen complexes produces poly(pentadecalactone)s with number-average molecular weights (Mn) of over 150 000 g/mol. Moreover, the same catalyst is also active in catalyzing the ROP of small and medium size lactones, which makes these aluminum-salen complexes highly potential catalysts for the cROP of lactones irrespective of ring size. These results show that it is possible to polymerize macrolactones to high molecular weight polyethylene-like polymers using cheap and robust metal-based catalysts. Even the so-called medium-sized lactones (ring size: 9-12) can be polymerized with a reasonably good activity to high molecular weight products, which is truly exceptional. These results complement the common theory of ring-tension-driven cROP. © 2011 American Chemical Society. Source

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