Design to realize integrated polymer products

P.E. Neerincx

Onderzoeksoutput: ScriptieDissertatie 1 (Onderzoek TU/e / Promotie TU/e)

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The goal of this thesis is to design and realize challenging process routes to obtain integrated technical polymer products by shifting the present limits. Essential is the need of concurrent engineering, which is the coupling between the concept of the design, the properties of the polymer, and the characteristics of the chosen process, which is injection moulding. The thesis elaborates this goal by using five related, but essentially different, product designs. The first example comprises the challenge of moulding thick, though precise and dimensionally stable, products by compensating shrinkage by applying either the gasassisted-injection moulding technique, eventually combined with chemical foaming or, more interesting, a moveable insert. The second design concerns a fully integrated disposable bioreactor for culturing and testing of tissue-engineered heart valves. The design consists out of two identical shells that are fabricated via a two component, hard and soft, injection moulding technique. The soft polymer is used for air pressure controlled membranes, that drive the fluid flow, and for the steering valves and the seals. The hard polymer comprises the casing parts that hold the soft parts in place. The bioreactor is designed via an iterative process, it is successfully realized, foreseen of a mature control system, and tested, imitating the cardiac pressures and cardiac flows needed during the culturing and testing of tissueengineered heart valves. Next, a downscaling step is investigated by integrating multiple membranes, valves and seals on a smaller scale in the third design, which is full-polymeric, multifunctional microfluidic reactor device. For this application special serpentine mixers are needed that are easy to fabricate on the interface between the two halves of a mould or device, realizing an almost perfect baker’s transformation. The efficient, flow splitting, rotating and recombining device possesses 10 elements that create 2·410 layers with an individual striation thickness of 0.5 [nm] in 10 seconds. A combination of two identical shells are used, that are each folded to occupy a 160 × 90 [mm2] space and subsequently stacked into a 4 (double) layer system. One microfluidic reactor unit includes 6 different in- and output connections, 6 peristaltic pumps, 18 volume-neutral, recoverable control valves, 2 fluid storages, and 2 serpentine mixers. The fourth example concerns even further downscaling in microfluidics applications by trying to mould micro channels by using controlled overmoulding. Hesitation effects (early freeze-in of the polymer melt) are normally a problem during injection moulding of products with non-uniform wall thicknesses. Here we use it as new technology by first moulding a thick layer, in which slots contain the micro structure, at high injection speeds, under high packing pressure and at high melt temperature for detailed filling. Hereafter the second layer is overmoulded on top of the first one. Slots are filled immediately where after the melt flow chooses to fill the remainder of the second layer, leaving the polymer micro structure unfilled. A polymer layered product containing micro channels remains. Different materials, process settings and channel dimensions are tested to explore the fabrication window of this technique. The last example concerns the challenge of structuring products by using static serpentine mixers on the parting surface of the mould to multiply, rotate and add layered structures. This could be useful for various product properties: structure layers parallel to the surface for barrier properties and toughness, layers perpendicular to the surface for soft touch and high accuracy touch screen applications. A combination of these methods can be used to create hierarchic structures which are most preferable in e.g. photovoltaic cells.
Originele taal-2Engels
KwalificatieDoctor in de Filosofie
Toekennende instantie
  • Mechanical Engineering
Begeleider(s)/adviseur
  • Meijer, Han, Promotor
Datum van toekenning31 mei 2012
Plaats van publicatieEindhoven
Uitgever
Gedrukte ISBN's978-90-386-3155-4
DOI's
StatusGepubliceerd - 2012

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