Stan Looijmans

Stan Looijmans
Eindhoven University of Technology | TUE · Department of Mechanical Engineering

Master of Science

About

18
Publications
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163
Citations
Introduction
Stan Looijmans is a doctoral candidate in the group of Polymer Technology at Eindhoven University of Technology (TU/e). The scope of his research is bridging the gap between processing-induced structure formation and (micro)mechanical properties. Key topics are the quantification of structure at the nanoscale using synchrotron radiation, the development of microscale mechanical testing methods and the numerical simulation of both the crystallization process and the local mechanical response.

Publications

Publications (18)
Article
Full-text available
Fiber-reinforced polymer composites are largely employed for their improved strength with respect to unfilled matrices. Considering semi-crystalline materials under relevant processing conditions, the applied pressure and flow induce shear stresses at the fiber–polymer interface. These stresses may strongly enhance the nucleation ability of the fib...
Article
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There has been extensive research in the field of material-extrusion (Mat-Ex) 3D printing to improve the inter-layer bonding process. Much research focusses on how various printing conditions may be detrimental to weld strength; many different feedstocks have been investigated along with various additives to improve strength. Surprisingly, there ha...
Article
While crystallization behavior of isotactic polypropylene homopolymers had been subject to a wide range of experimental and modeling studies, this is not the case for propylene-ethylene random copolymers (PPR). This class of polymers offers up to now significant challenges, both from an experimental as well as a modeling perspective. The ethylene i...
Article
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Thermoplastic semi-crystalline polymers are excellent candidates for tissue engineering scaffolds thanks to facile processing and tunable properties, employed in melt-based additive manufacturing. Control of crystallization and ultimate crystallinity during processing affect properties like surface stiffness and roughness. These in turn influence c...
Article
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In the area of polymer crystallization, the most widely used techniques to quantify structure, morphology and molecular orientation are fundamentally based on light or X‐ray scattering and absorption. In particular, synchrotron X‐rays are used for detailed studies on the semicrystalline structure in polymeric materials. The technical requirements f...
Article
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In the selective laser sintering of polymers, the most widely used powders are based on polyamide 12 (PA12), which is a semi-crystalline polymer. Because the mechanical properties of the printed parts depend largely on the microstructure, knowledge on the crystalline architecture is important. We developed a numerical model based on the finite elem...
Article
During the lifetime of polycarbonate surfaces, which for example are used as helmets or protective eye visors, friction and abrasive wear may result from scratching or sliding cycles. Previous research showed that it is essential to understand the intrinsic mechanical response of the polymer in order to further investigate its frictional and wear r...
Article
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Isotactic polypropylene (iPP) is a low cost semi-crystalline polymer that is easy to process, has a wide variety in properties and is, therefore, used in many applications. Many of these applications require enhanced wear-resistance to prolong the lifetime of the product. Essential is to first investigate the intrinsic response of the material in o...
Article
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Over the last two decades the study of friction has been an important topic in polymer tribology. The obtained knowledge about friction phenomena enables to take the next step towards understanding wear in polymers. When increasing the amount of local deformation in sliding friction experiments, the onset of failure is obtained, i.e. periodic crack...
Article
Cross-nucleation is defined as the nucleation of one polymorph on the surface of another polymorph of the same substance. Although the description of this particular form of heterogeneous nucleation is mainly phenomenological, recently dedicated quantitative studies are performed on several systems. In this work we propose a model framework that ca...
Article
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Nowadays, in many applications metal parts are replaced by light-weight polymer products. As a result of the processing history, these polymer fabricates are, more often than not, anisotropic, leading to a direction dependent mechanical performance. Recently we showed the frictional response of isotactic polypropylene is improved by pre-stretching...
Article
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Polymers are increasingly used in applications where relative moving parts are in contact. The dissipation of energy due to friction, i.e. heat production, reduces a product's lifetime significantly. Since in processing often an extrusion or injection moulding step is used in product formation, the induced anisotropic microstructure leads to a spat...
Article
Full-text available
A particular kind of heterogeneous nucleation, i.e., cross-nucleation, is sometimes observed in polymorphic substances, when a new crystal structure nucleates on the surface of a crystal of a different modification. Here we show a unique and apparently incongruous nucleation behaviour in polymorphic isotactic polypropylene (i-PP). The rate of cross...

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