FG Polymertechnik und Polymerphysik

12 Items

Recent Submissions
A constitutive analysis of nonlinear shear flow

Narimissa, Esmaeil ; Schweizer, Thomas ; Wagner, Manfred H. (2020-06-03)

We analyse shear stress and normal stress data obtained by cone-partitioned-plate (CPP) shear rheometry in recent years. The data sets of Schweizer et al. (Rheol. Acta 47, 943–957, 2008 ) and Costanzo et al. (Macromolecules 49, 3925–3935, 2016; & Fluids 4, 28, 2019 ) on nearly monodisperse polystyrene melts and solutions are considered to be among the most reliable shear data available. The Doi...

Universality of steady shear flow of Rouse melts

Poh, Leslie ; Narimissa, Esmaeil ; Wagner, Manfred H. (2020-08-29)

The data set of steady and transient shear data reported by Santangelo and Roland Journal of Rheology 45: 583–594, (2001) in the nonlinear range of shear rates of an unentangled polystyrene melt PS13K with a molar mass of 13.7 kDa is analysed by using the single integral constitutive equation approach developed by Narimissa and Wagner Journal of Rheology 64:129–140, (2020) for elongational and ...

Insights into Nano-Scale Physical and Mechanical Properties of Epoxy/Boehmite Nanocomposite Using Different AFM Modes

Ghasem Zadeh Khorasani, Media ; Silbernagl, Dorothee ; Platz, Daniel ; Sturm, Heinz (2019-02-01)

Understanding the interaction between nanoparticles and the matrix and the properties of interphase is crucial to predict the macroscopic properties of a nanocomposite system. Here, we investigate the interaction between boehmite nanoparticles (BNPs) and epoxy using different atomic force microscopy (AFM) approaches. We demonstrate benefits of using multifrequency intermodulation AFM (ImAFM) to...

The effect of boehmite nanoparticles (γ‐AlOOH) on nanomechanical and thermomechanical properties correlated to crosslinking density of epoxy

Ghasem Zadeh Khorasani, Media ; Silbernagl, Dorothee ; Szymoniak, Paulina ; Hodoroaba, Vasile-Dan ; Sturm, Heinz (2019-01-02)

We show that complex physical and chemical interactions between boehmite nanoparticles and epoxy drastically affect matrix properties, which in the future will provide tuning of material properties for further optimization in applications from automotive to aerospace. We utilize intermodulation atomic force microscopy (ImAFM) for probing local stiffness of both particles and polymer matrix. Sti...

Brandphänomene von Polyurethanschäumen im Hinblick auf deren Interaktion, Abhängigkeit und Konkurrenz

Günther, Martin (2020)

Due to their unique material properties, polyurethane foams are widely used in industry and surround us in our daily life. Rigid foams insulate buildings, flexible foams cushion the sub- way seats on our way to work, and at night, foam mattresses guarantee a pleasant sleep. How- ever, their fire phenomena necessitate the modification of their burning behavior since they exhibit a short time to ...

Herstellung und Eigenschaften von Spritzguss-Formteilen mit 3D-gedruckten Inserts zur lokalen Verstärkung

Klaski, Jens (2020)

In der vorliegenden Dissertation wird die Kombination der Fertigungsverfahren Spritzguss und 3D-Druck untersucht. Es werden einige Anwendungen für die Verfahrenskombination aufgezeigt, wobei die Untersuchung der lokalen Verstärkung von Spritzgussteilen im Fokus steht. Für die Untersuchung der Verstärkung werden Inserts, welche mittels des Verfahrens Fused Deposition Modeling hergestellt werden,...

Atomic force microscopy-based nanoscopic studies of epoxy/boehmite nanocomposites

Ghasem Zadeh Khorasani, Media (2020)

Development of lightweight parts made of fiber-reinforced polymer composites for aerospace and automotive industry has been focus of many studies over the past several decades. Nanofillers added to the epoxy matrices used in such composite parts results in remarkable improvement of matrix-dominated properties. Formation of interphases between inorganic nanofillers and polymer matrices is usuall...

Rheological and Mechanical Gradient Properties of Polyurethane Elastomers for 3D-Printing with Reactive Additives

Wang, Peng ; Auhl, Dietmar ; Uhlmann, Eckart ; Gerlitzky, Georg ; Wagner, Manfred H. (2019-12-31)

Polyurethane (PU) elastomers with their broad range of strength and elasticity are ideal materials for additive manufacturing of shapes with gradients of mechanical properties. By adjusting the mixing ratio of different polyurethane reactants during 3D-printing it is possible to change the mechanical properties. However, to guarantee intra- and inter-layer adhesion, it is essential to know the ...

Development and Application of a Statistically-Based Quality Control for Crowdsourced Air Temperature Data

Napoly, Adrien ; Grassmann, Tom ; Meier, Fred ; Fenner, Daniel (2018-08-29)

In urban areas, dense atmospheric observational networks with high-quality data are still a challenge due to high costs for installation and maintenance over time. Citizen weather stations (CWS) could be one answer to that issue. Since more and more owners of CWS share their measurement data publicly, crowdsourcing, i.e., the automated collection of large amounts of data from an undefined crowd...

Piezo-Plunger Jetting Technology: An Experimental Study on Jetting Characteristics of Filled Epoxy Polymers

Kurz, Alexander ; Bauer, Jörg ; Wagner, Manfred (2019-02-01)

The droplet formation of Newtonian fluids and suspensions modified by spherical, non-colloidal particles has attracted much interest in practical and theoretical research. For the present study, a jetting technique was used which accelerates a geometrically defined plunger by a piezoelectric actuator. Changing rheological properties of materials and extending deformation rates towards nonlinear...

Short- and Long-Range Mechanical and Chemical Interphases Caused by Interaction of Boehmite (γ-AlOOH) with Anhydride-Cured Epoxy Resins

Ghasem Zadeh Khorasani, Media ; Elert, Anna-Maria ; Hodoroaba, Vasile-Dan ; Agudo Jácome, Leonardo ; Altmann, Korinna ; Silbernagl, Dorothee ; Sturm, Heinz (2019-06-04)

Understanding the interaction between boehmite and epoxy and the formation of their interphases with different mechanical and chemical structures is crucial to predict and optimize the properties of epoxy-boehmite nanocomposites. Probing the interfacial properties with atomic force microscopy (AFM)-based methods, especially particle-matrix long-range interactions, is challenging. This is due to...

Effect of Shear Rate on the Orientation and Relaxation of a Vanillic Acid Based Liquid Crystalline Polymer

De Kort, Gijs W. ; Leoné, Nils ; Stellamanns, Eric ; Auhl, Dietmar ; Wilsens, Carolus H. R. M. ; Rastogi, Sanjay (2018-08-22)

In this study, we report on the visco-elastic response during start-up and cessation of shear of a novel bio-based liquid crystal polymer. The ensuing morphological changes are analyzed at different length scales by in-situ polarized optical microscopy and wide-angle X-ray diffraction. Upon inception of shear, the polydomain texture is initially stretched, at larger strain break up processes be...