References of "Fritz, Hans-Gerhard"
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See detailContinuous reactive extrusion polymerization of L-lactide - an engineering view
Jacobsen, Sven; Fritz, Hans-Gerhard; Degée, Philippe et al

in Macromolecular Symposia (2000), 153

Polylactides (PLA), biodegradable aliphatic polyesters, produced from renewable resources might substitute petrochemically based polymers in a broad range of applications in the near future, if we manage ... [more ▼]

Polylactides (PLA), biodegradable aliphatic polyesters, produced from renewable resources might substitute petrochemically based polymers in a broad range of applications in the near future, if we manage to produce them at lower cost and higher efficiency than nowadays. Possible applications include food packaging for meat and soft drinks, films for agro-industry and non-wovens in hygienic products. The authors developed, based on a new catalytic system, a reactive extrusion polymerisation process, which can be used to produce PLA continuously in larger quantities and at lower costs than before. This extrusion polymerisation process has been developed and tested with laboratory scale machines and has to be transferred to industrial processing equipment. This paper aims to address the problems attached with this transfer and to discuss the chances to finally achieve low cost PLA at industrial scale. [less ▲]

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See detailNew developments on the ring opening polymerisation of polylactide
Jacobsen, Sven; Fritz, Hans-Gerhard; Degée, Philippe et al

in Industrial Crops & Products (2000), 11

Polylactides (PLA), biodegradable aliphatic polyesters, produced solely from renewable resources may substitute petrochemically based polymers in a broad range of applications in the near future, if we ... [more ▼]

Polylactides (PLA), biodegradable aliphatic polyesters, produced solely from renewable resources may substitute petrochemically based polymers in a broad range of applications in the near future, if we manage to produce them at lower cost and higher efficiency as nowadays. Possible applications include food packaging for meat and soft drinks, films for agro-industry and non-wovens in hygienic products. The authors developed, based on a new catalytic system, a reactive extrusion polymerisation process, which can be used to produce PLA continuously in larger quantities and at lower costs than before. This extrusion polymerisation process has been developed and tested with laboratory scale machines and the possibilities to extend this polymerisation process to lactide based blockcopolymers have been investigated. [less ▲]

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See detailNew catalysis for fast bulk ring-opening polymerization of lactide monomers
Degée, Philippe; Dubois, Philippe ULg; Jérôme, Robert ULg et al

in Macromolecular Symposia (1999), 144

The ring-opening polymerization of lactides has been studied in bulk using either 2-ethylhexanoic acid tin(II) salt, Sn(Oct)2, or aluminum triisopropoxide, Al(OiPr)3, as the initiator over a wide range of ... [more ▼]

The ring-opening polymerization of lactides has been studied in bulk using either 2-ethylhexanoic acid tin(II) salt, Sn(Oct)2, or aluminum triisopropoxide, Al(OiPr)3, as the initiator over a wide range of temperature and monomer-to-initiator molar ratio, A high increase in the bulk polymerization rate has been observed when the initiator was added with an equimolar amount of a Lewis base, such as triphenylphosphine and 4-picoline (C6H7N) added to Sn(Oct)2 and Al(OiPr)3, respectively Melt stable polylactides of high molecular weight and reasonably narrow molecular weight distribution have been accordingly prepared. The use of the Sn(Oct)2. equimolar combination has allowed for reaching an acceptable balance between propagation and depolymerization rates, so that the polymerization is fast enough to be performed through a continuous single-stage process in a twin-screw extruder A global activation mechanism is proposed and discussed by comparison with both investigated initiation systems. [less ▲]

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See detailPolylactide (PLA) – A new way of production
Jacobsen, Sven; Degée, Philippe; Fritz, Hans-Gerhard et al

in Polymer Engineering & Science (1999), 39(7), 1311-1319

Poly(lactide) (PLA), a biodegradable aliphatic polyester with excellent properties for different polymer applications, has been used mostly in the biomedical field, mainly because of its high price ... [more ▼]

Poly(lactide) (PLA), a biodegradable aliphatic polyester with excellent properties for different polymer applications, has been used mostly in the biomedical field, mainly because of its high price, resulting from expensive polymerization and purification techniques. Although this polymer can play a major role in future markets for biodegradable polymers, the current high price has to be reduced significantly to at least $4 US/kg. Therefore, this paper aims to partially review the polymerization techniques traditionally used in PLA synthesis and to propose new developments that enable us to produce these polymers by an innovative process for just a portion of the costs traditionally charged, using reactive extrusion techniques in a closely intermeshing co-rotating twin screw extruder. This paper gives an overview of attainable mechanical properties and future markets. [less ▲]

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