NachhaltigAngewandte Naturwissenschaften und WirtschaftsingenieurwesenTAZ SpiegelauZeitschriftenartikel
Benedikt Scharfe, S. Lehmann, Thorsten Gerdes, D. Brüggemann
Optical and Mechanical Properties of Highly Transparent Glass-Flake Composites
Journal of Composites Science, vol. 3, no. 101, pp. 1-17
2019
DOI: 10.3390/jcs3040101
Abstract anzeigen
In this paper, the dynamic mechanic and optical properties of composites made of Polyvinyl
Butyral (PVB) and Micro Glass Flakes (MGF) with matching refractive indices (RIs) are investigated.
The composite is produced by a slurry-based process using additional blade casting and lamination.
It can be shown that a high degree of ordering of the MGF in the polymer matrix can be achieved
with this method. This ordering, combined with the platelet-like structure of the MGF, leads to very
efficient strengthening of the PVB with increasing content of the MGF. By carefully adjusting the
RIs of the polymer, it is shown that haze is reduced to below 2%, which has not been achieved with
irregular fillers or glass fibers.
NachhaltigAngewandte Naturwissenschaften und WirtschaftsingenieurwesenTAZ SpiegelauZeitschriftenartikel
L. Schwinger, S. Lehmann, L. Zielbauer, Benedikt Scharfe, Thorsten Gerdes
Aluminum Coated Micro Glass Spheres to Increase the Infrared Reflectance
Coatings (Special Issue "Current Research in Thin Film Deposition: Applications, Theory, Processing, and Characterisation"), vol. 9, no. 3
2019
DOI: 10.3390/coatings9030187
Abstract anzeigen
The reflective properties of micro glass spheres (MGS) such as Solid Micro Glass Spheres (SMGS, “glass beads”) and Micro Hollow Glass Spheres (MHGS, “glass bubbles”) are utilized in various applications, for example, as retro-reflector for traffic road stripe paints or facade paints. The reflection behavior of the spheres can be further adapted by coating the surfaces of the spheres, e.g., by titanium dioxide or a metallic coating. Such coated spheres can be employed as, e.g., mid infrared (MIR)-reflective additives in wall paints to increase the thermal comfort in rooms. As a result, the demand of heating energy can be reduced. In this paper, the increase of the MIR-reflectance by applying an aluminum coating on MGS is discussed. Aluminum coatings are normally produced via the well-known Physical Vapor Deposition (PVD) or Chemical Vapor Deposition (CVD). In our work, the Liquid Phase Deposition (LPD) method, as a new, non-vacuum method for aluminum coating on spherical spheres, is investigated as an alternative, scalable, and simple coating process. The LPD-coating is characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and reflection measurements. The results are compared to a reference PVD-coating. It is shown that both sphere types, SMGS and MHGS, can be homogeneously coated with metallic aluminum using the LPD method but the surface morphology plays an important role concerning the reflection properties. With the SMGS, a smooth surface morphology and a reflectance increase to a value of 30% can be obtained. Due to a structured surface morphology, a reflection of only 5% could be achieved with the MHGS. However, post-treatments showed that a further increase is possible.
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