000230032 001__ 230032
000230032 005__ 20190717172529.0
000230032 0247_ $$2doi$$a10.5075/epfl-thesis-7868
000230032 02470 $$2urn$$aurn:nbn:ch:bel-epfl-thesis7868-7
000230032 02471 $$2nebis$$a10962549
000230032 037__ $$aTHESIS
000230032 041__ $$aeng
000230032 088__ $$a7868
000230032 245__ $$aHybrid Processing of Thermoplastic Based Multimaterials
000230032 260__ $$bEPFL$$c2017$$aLausanne
000230032 269__ $$a2017
000230032 300__ $$a164
000230032 336__ $$aTheses
000230032 502__ $$aProf. Dirk Grundler (président) ; Prof. Jan-Anders Månson, Dr Pierre-Etienne Bourban (directeurs) ; Prof. Heinrich Hofmann, Dr Nicolas Bernet , Prof. Johnathan Goodsell  (rapporteurs)
000230032 520__ $$aThere is a growing interest in exploring novel material combinations and processing technology to manufacture complex 3D shaped polymer and composite structures. In the field of prosthetics and orthotics, this need is significant with additional challenges of providing patient specific customization to these devices in a cost-effective manner. Thermoplastic based materials(TP) including thermoplastic elastomers (TPE) and their composite counterparts have the potential to address these applications.  The objectives of the research are to develop composite preforms that can conform to complex 3D structures, understand the processing phenomena in particular the fusion bonding mechanisms of different thermoplastic materials forming hard and soft interfaces and finally develop processing strategies that are suitable for the manufacture of complex 3D structures with these multimaterials.   A novel TPE based composite preform consisting of continuous glass fibres was first manufactured by a continuous melt impregnation technique, extremely well suited for the studied TPE material. This process resulted in superior fibre wetting and impregnation characteristics for the composite preform. Furthermore, TPE reinforced by glass fibres provided preforms which can conform easily to 3D shapes owing to the flexible nature of the matrix. Then isothermal integration of polypropylene based glass fibre (iPPGF) composites with the TPE materials was studied and the bond strengths of bilayer specimens under different processing conditions were determined. The bonding temperature and pressure were tuned to promote the best fusion bonding conditions which was verified from peel tests and microscopic characterization of the interfaces.   Further improvements in bond strength and fusion bonding time was achieved by non-isothermal fusion bonding techniques namely overmolding and 3D printing. The processing windows were then obtained for these two processes under a wide range of fusion bonding conditions and for various TPE and TP based materials. The presence of a continuous plasticized iPP phase in the TPE was determined to play an important role in the bonding through the establishment of intimate contact and interdiffusion mechanisms during the molding process. The influence of the interface temperature and bonding pressure was shown to govern the wetting and intimate contact of the interfaces and to compensate shrinkage respectively. The established processing conditions permitted tailoring of the bond strengths for TPE-iPP and TPE-iPPGF interfaces. These results can be directly applied for high volume manufacture of complex 3D shaped composite parts. The effects of the TPE composition (fillers, reinforcements, TP content, surface roughness
) and of bonding temperature, pressure and time, were thus better understood under the non-isothermal bonding conditions encountered in the additive processes. The results of the FDM printing can be combined with other low pressure processing techniques such as thermoforming to manufacture hybrid multimaterials 3D structures.  The research is applied in developing a hybrid processing technology which proposes the combination of thermoplastic-based multimaterials and different processing techniques that are suitable for the manufacture of the next generation of composite applications in particular for customized affordable prosthetic limbs.
000230032 6531_ $$aFusion bonding
000230032 6531_ $$aTPEs
000230032 6531_ $$athermoplastics
000230032 6531_ $$acomposites
000230032 6531_ $$aovermolding
000230032 6531_ $$aFDM
000230032 6531_ $$a3D printing
000230032 700__ $$0246732$$g203378$$aChandran, Rajasundar
000230032 720_2 $$aMånson, Jan-Anders$$edir.$$g105745$$0241291
000230032 720_2 $$aBourban, Pierre-Etienne$$edir.$$g104610$$0240394
000230032 8564_ $$zn/a$$yn/a$$uhttps://infoscience.epfl.ch/record/230032/files/EPFL_TH7868.pdf$$s37925330
000230032 909C0 $$xU10339$$pLTC$$0252013
000230032 909CO $$pthesis-bn2018$$pDOI$$ooai:infoscience.tind.io:230032$$qDOI2$$qGLOBAL_SET$$pthesis
000230032 917Z8 $$x108898
000230032 917Z8 $$x108898
000230032 918__ $$dEDMX$$cIMX$$aSTI
000230032 919__ $$aLTC
000230032 920__ $$b2017$$a2017-8-3
000230032 970__ $$a7868/THESES
000230032 973__ $$sPUBLISHED$$aEPFL
000230032 980__ $$aTHESIS