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Logo: SFB/TRR 123 "PlanOS"
Logo Leibniz Universität Hannover
Logo: SFB/TRR 123 "PlanOS"
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Projects – Details

S02 - Hybrid polyme systems

Supervisor:Prof. Hanemann
Researcher:Kirsten Honnef und Uwe Gleissner
Funded by:DFG

During the funding period of 4 years the research will focus on three main topics:

Oops, an error occurred! Code: 20210124064900451c45d6Modification of refractive index: The refractive index of selected polymers will be significantly increased in the wavelength range of 400 to 1100 nm. The research will focus on methacrylate and epoxy based reactive resin systems. After hardening, these systems form polymethacrylates or epoxides. The increase of refractive index will be achieved by solving electron rich aromatic and non-dyeing compounds (e.g. phenanthrene) which are transparent in the visible range up to their maximum solubility. In case of methacrylates the possibility of increasing refractive index by copolymerisation with sidechain modified methacrylate monomer (e.g. benzyl methacrylate) will be also investigated. This monomer has already an electron rich, aromatic phenyl moiety as a side group which will substantially contribute to a higher refractive index. The aim is to increase the refractive index from 1.49 (pure polymethylmethacrylate) up to 1.56 and from 1.55 (epoxy) to 1.65 (all values for a wavelength of 589 nm).

Oops, an error occurred! Code: 20210124064900663a3270Adjustment of thermo-mechanical properties: Depending on the monomer type a thermoplastic or thermoset is synthesized. Suitable highly transparent epoxides polymerise mainly as thermosets. However increasing glass transition temperatures and thus increasing continuous operating temperatures can also be achieved by multifunctional monomers, like 1,3-Butandiol-dimethacrylate (BDMA), which compensate the plasticizing effect caused by the dopants. The crosslinking is supposed to prevent increasing polymer chain mobility in order to retain or elevate glass transition temperature. At least the plasticizing effect should be eliminated, it would even be better if it will be overcompensated to achieve a huge maximum continuous operating temperature. Shaping within the shaping related subprojects will be done during polymerisation (thermoplastic and reactive molding, respectively). By adding additives or choosing suitable monomers an individual adjustment of the reactive resin viscosity is possible. This is very important for the different shaping or molding processes. Aspired viscosity values will range from 0.05 to 10 Pa s (at room temperature), depending on the material composition. According to that it will be possible to provide reactive resins which will have customized viscosity and modified refractive index values for e.g. ink-jet and offset printing.

Within the first two milestones these new polymer systems will be handed over non- polymerized and with adjusted viscosity (methacrylates, epoxies) to the printing and reaction molding subprojects. In the same way polymerized and modified methacrylates are delivered to the hot-embossing subprojects. For following material properties adjustments a close cooperation with shaping and characterization subprojects is very important. Furthermore an additional refractive index increase and stabilization of continuous operation temperatures is scheduled to enhance the variety of materials and properties.

Development of luminescent hybrid polymers: In the second half of the project new hybrid polymers which luminescence in the visible range will be developed. Organic rare earth complex compounds, e.g. based on europium, emit light in the visible range after optical excitation. Within the project active i.e. emitting hybrid polymers with customized refractive indices and complex compounds will be developed enabling active waveguide components. In a second step material properties will be matched in cooperation with the other shaping subprojects to achieve a waveguide fabrication with the technologies inside the SFB/TRR123-project.



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