Synthesis and structural characterization of group 4 metal alkoxide complexes of N, N, N ′,N ′-tetrakis(2-hydroxyethyl)ethylenediamine and their use as initiators in the ring-opening polymerization (ROP) of rac -lactide under industrially relevant conditions
Chuck C.J.,University of Bath |
Davidson M.G.,University of Bath |
Gobius Du Sart G.,Corbion Purac |
Ivanova-Mitseva P.K.,University of Bath |
And 2 more authors.
Inorganic Chemistry | Year: 2013
A series of N,N,N′,N′-tetrakis(2-hydroxyethyl)ethylenediamine (TOEEDH4) ligand precursors and their group 4 metal complexes have been prepared. The complexes have been characterized by single-crystal X-ray diffraction and 1H NMR spectroscopy, highlighting the ability to systematically vary the number of TOEED ligands within the system. Initial catalytic data for the solvent-free, ring-opening polymerization of rac-lactide (rac-LA), a promising degradable polymer produced from renewable resources, is reported. At 135 C, it has been demonstrated that the activity of the complexes is enhanced by increasing the number of labile isopropoxide groups. When the temperature was further increased to 165 C, all complexes demonstrated a far higher activity irrespective of the identity of the metal or number of labile initiator groups. Polymerization kinetics were monitored in real time using FT-IR spectroscopy with a diamond composite insertion probe and Ti 4(TOEED)(OiPr)12 was demonstrated to convert over 95% of the rac-LA within 160 min. © 2013 American Chemical Society.
Kuepper J.,RWTH Aachen |
Ruijssenaars H.J.,Corbion Purac |
Blank L.M.,RWTH Aachen |
de Winde J.H.,Leiden University |
Wierckx N.,RWTH Aachen
Journal of Biotechnology | Year: 2015
Pseudomonas putida S12 is a solvent-tolerant gamma-proteobacterium with an extensive track record for production of industrially relevant chemicals. Here we report the annotated complete genome sequence of this organism, including the megaplasmid pTTS12 which encodes many of the unique features of the S12 strain. © 2015 Elsevier B.V.
Huang W.,Ningbo Institute of Materials Technology and Engineering |
Huang W.,Ningbo University |
Luo X.-Z.,Ningbo Institute of Materials Technology and Engineering |
Wang B.-J.,Ningbo Institute of Materials Technology and Engineering |
And 6 more authors.
Macromolecular Chemistry and Physics | Year: 2015
Nanostructures of stereocomplex polylactide (sc-PLA) are obtained and studied in poly(l-lactide) (PLLA) doped with a low amount of poly(d-lactide) (PDLA) during successive melt-quenching, extrusion, spinning, and drawing processes corresponding to quiescent, shear flow, elongational flow, and tensioned annealing conditions, respectively. Nanogranules of predominantly sc-PLA are initially formed with rapid quenching in quiescent and shear flow, which developed into microspheres with slow quenching and uniform nanofibrils in elongational flow. While only amorphous or the α′-form PLLA is formed with the quenched melts and macroscopic fibers, the embedded nanogranules and nanofibrils are highly crystallized with the coexistence of sc-PLA and the α-crystals. A 1D coalescence of nascent sc-nuclei into nanofibrils in elongational flow is preliminarily proposed to explain the structure evolution and the minor reinforcement of the nanofibrils on the macroscopic fibers. Nanostructures of predominantly stereocomplex polylactide (sc-PLA), including nanogranules and nanofibrils, are obtained during direct melt process of poly(l-lactide) doped with poly(d-lactide). The nanostructures take diverse, but well-defined, morphologies and substructures, as governed by thermal and flow conditions. This opens up a facile and scalable route toward either all-PLA nanocomposites or nanofibrils and membranes of sc-PLA. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Huyskens C.,Institute for Sustainable Process Technology ISPT |
Huyskens C.,Flemish Institute for Technological Research |
Helsen J.,Flemish Institute for Technological Research |
Groot W.J.,Corbion Purac |
And 2 more authors.
Separation and Purification Technology | Year: 2015
The bio-based industry is striving to replace refined sugars by much cheaper secondary feedstocks for the production of bio-fuels and chemicals. However, due to their higher complexity, a number of technological challenges need to be overcome. One example are the high concentrations of sodium and potassium present in the biomass hydrolysates that inhibit fermentation and hence need to be reduced. Previous research demonstrated the technical feasibility of membrane capacitive deionization (MCDI) for biomass hydrolysate desalination as a chemical/waste free alternative compared to the commonly used ion-exchange process (IEX). In this paper, the economic viability of MCDI was investigated for a production capacity of 500 ton sugar day-1 and a target Na removal from 3 to 0.1 g kg-1 hydrolysate. Although capital costs were higher for MCDI than for IEX due to the expensive MCDI cells and power supplies, operating costs were lower because less water and chemicals are used and less wastewater is generated. Cost calculations for different initial feed concentrations indicated that IEX was only preferential over MCDI when the feed Na+ concentration was below 0.4 g kg-1 hydrolysate. Then the higher chemical, water and wastewater treatment costs for IEX no longer outweighed the higher cost of MCDI cells compared to IEX resins. © 2015 Elsevier B.V. All rights reserved.
Xiong Z.,Beijing Institute of Fashion Technology |
Xiong Z.,CAS Beijing National Laboratory for Molecular |
Zhang X.,Beijing Institute of Fashion Technology |
Wang R.,Beijing Institute of Fashion Technology |
And 4 more authors.
Polymer (United Kingdom) | Year: 2015
An aryl amide derivative (TMB-5) was used to nucleate the poly(l-lactide)/poly(d-lactide) (PLLA/PDLA) blend for the first time. The effect of TMB-5 nucleating agent on the crystallization behavior of PLLA/PDLA blend was systematically investigated. The selective nucleation of stereocomplex (sc) crystals by incorporation of TMB-5 was realized under appropriate crystallization conditions. During the cooling process, various morphology of TMB-5 due to its partial or complete dissolution in the PLLA/PDLA blend melt was observed. Furthermore, an sc crystals layer on the lateral surface of TMB-5 was found. Upon cooling a PLLA/PDLA blend from 260 °C at rates between 2 and 100 °C/min, 0.5 wt% addition of TMB-5 induced a single melting peak of sc crystals and no homocrystallization was observed in the subsequent DSC heating scan. The melting temperature of the sc crystals was found to decrease in the presence of TMB-5 from 230 to ca. 200 °C, which is still 20 °C higher than that of PLLA homopolymer. The results suggest that the supramolecular structure of the nucleating agent plays an important role in the crystallization of the PLLA/PDLA blend. The difference in solubility and recrystallization ability of TMB-5 in polymer melt results in the variation of crystallization behavior of PLLA/PDLA blend, which is correlated with the concentration of TMB-5 and crystallization conditions including the final melting temperature, annealing time and cooling rate. © 2015 Elsevier Ltd. All rights reserved.