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Aufsatz
Cross-Linked Hydrophobic Starch Granules in Blends with PLA
(2018-04-17)
The majority of native starch is used in the food sector and in the paper industry. Only a small amount is used in polymer engineering. One reason for the reluctance of the plastics processing industry to use starch as a filling material in polymer blends is the unsatisfactory mechanical behavior of starch when combined with thermoplastics. Another reason is the hydrophilicity of starch. In order to make these materials capable of competing, an amelioration of the mechanical properties is compulsory. By means of ...
Konferenzveröffentlichung
UV light irradiation of fibers in thermoplastic pultrusion for higher surface energy
(Society of Plastics Engineers, 2018)
Pultrusion is a common way to produce thermoplastic composites reinforced with different kinds of fibers. There are many different opportunities to improve the properties of a thermoplastic material. Different kind of fibers where pultruded in combination with different thermoplastic materials. The fiber content was set to 30wt% comparing the roving strain with the pultruded strain. UV-C light was used in the process to improve the fiber matrix adhesion. The pultruded strain was granulated and injection molded to ...
Aufsatz
Characterization of Anisotropic Properties of Hot Compacted Self-Reinforced Composites (SRCs) via Thermal Diffusivity Measurement
(2019-11-01)
The mechanical properties of self-reinforced composites (SRCs) produced in a hot compaction process significantly depend on the process parameters. Only a little deviation of the process temperature or pressure causes the component to act differently under mechanical load. This is a chance and a challenge at the same time, since this process is difficult to handle but by properly controlling the process parameters, the mechanical properties can be adjusted, even locally for one component. In this research SRC are ...
Aufsatz
A Closer Look at the Bonding Capacity of Thick Metal-Plastic Hybrids
(2019-03-01)
Metal-plastic hybrids have a lot of advantages compared to purely metal or purely plastic parts. A good design for metal-plastic hybrids can help to save weight, for example in automotive applications. Therefore, it is important to understand the joining mechanisms between both materials. Aluminum AlSi9Cu3(Fe) and polyamide 6.6 with 35 % glass fibers were used as joining partners. The materials were joined by enclosing the metal part at least partially with plastic right inside the injection molding tool. Afterwards, ...
Aufsatz
UV Pre-Treatment for Polycarbonate for Bonding LSR in a Multi-Component Injection Molding Process
(2019-03-01)
In this study, the influence of UVC radiation and the influence of ozone on the surface energy of specimens made of polycarbonate were investigated. In an additional step, the peeling resistance of silicone flaps, which were overmolded, onto pre-treated PC plates of multicomponent specimens were analyzed. For this purpose, the samples were exposed to UVC radiation for different lengths of time, ranging from 5 s to 3 600 s. To further evaluate the influence of the ozone created by the UVC in the presence of oxygen, ...
Aufsatz
Additive manufacturing of Co-Ni-Ga high-temperature shape memory alloy - Processability 3 and phase transformation behavior
(2019)
Co-Ni-Ga high-temperature shape memory alloy is additively processed by selective laser melting for the first time. Reversiblemartensitic transformation of the as-built material is proven by differential scanning calorimetry. Microstructural analysis reveals a columnar-grained microstructure due to epitaxial solidification. Columnar-grained microstructures are characterized by a very low degree of constraints being beneficial for superior functional performance in numerous shape memory alloys. However, process-induced ...
Aufsatz
Investigations on Tightness of Polymer-Metal Hybrids in Environments with Thermal, Media, and Mechanical Loads
(2017-07-31)
With polymer-metal hybrids becoming more commonly used as structural components it was investigated how they perform in complex environments with combined thermal, media, and mechanical loads. Special attention was put on media tightness under said loads. This paper sums up the activities of the polymer technology research group of the University of Kassel on hybrids produced by overmolding metal inserts. Investigations concerning joint strength and influence of (cyclic) temperature loads and chemical corrosion on ...
Aufsatz
Mechanical Properties of Polydimethylsiloxane as a Function of the Amount and Type of Crosslinking Agent
(2017-06-13)
In this investigation, a high-consistency rubber (HCR) was mixed with five different, typically used crosslinking agents that are based on organic peroxide. Furthermore, the amount of crosslinking agent was varied in order to quantify the effect on the mechanical properties. All materials were processed in a hot pressing process, and, subsequently, post-cured. The properties were characterized by the measurement of the swelling ratio, shore A-hardness, rebound resilience and tensile test. We successfully proved that ...
Aufsatz
Pathways towards grain boundary engineering for improved structural performance in polycrystalline Co-Ni-Ga shape memory alloys
(2018)
Co-Ni-Ga high-temperature shape memory alloys attracted a lot of scientific attention due to their superior functional material properties in recent years. In the single crystalline state Co-Ni-Ga HT-SMAs feature a good pseudoelastic response up to 500°C. However, in the polycrystalline condition Co-Ni-Ga suffers significant grain constraints and premature fracture at grain boundaries. In this regard, crystallographic orientation of the grain being involved as well as morphology and geometrical orientation of the ...
Dissertation
Materialmodellierung für die simultane Kalt-/Warmumformung auf Basis erweiterter rheologischer Modelle
(kassel university press, 2014)