Material Engineering

Institut für Kunststofftechnik

Research topics

In order to make a material more efficacious, that is, to make its property profile wider or deeper, the current condition of the material must be ascertained using suitable material testing methods. In plastics engineering, a plastic orginates from a preparation process, initially through an innovation combination of polymers and additives. Furthermore, material engineering also aims at predicting the material behavior in practice. Therefore, the IKT researches on complex material models that, for example, depict time and temperature behavior realistically.

Current research

Initial Situation

  • 60 million tons of ligning per year remain from papermaking
  • Lignin is one of the most occur biopolymer in the world

Issue

  • Use of this sustainable an biobased resource by new technologies

Goal

  • Development of lignin-compounds for the production of high-quality components by laser sintering

Approach

  • Material Development with a customized processing window for laser sintering
  • Development of the production process for the laser sintering powders

Goal

  • Incoming rheological analysis
  • Increasing the molecular weight of standard-PLA by chain extension, chain branching or cross-linking.
  • Forming a physical network through the formation of PLA stereo complexes (expensive)
  • Test series in the laboratory on extrusion foaming machine
3D printing of highly filled plastics, e.g. thermal conductive plastics

Initial Situation

  • More and more filled plastics are available for 3D printing
  • Yet, most 3D printers aren’t designed for filled plastics

Goal

  • Developing new design tools to optimize 3D printing processes

Approach

  • First-time simulation of highly filled plastics in 3d printing
  • Developing new models and simulation approaches
  • Integral treatment of material and process simulation

Goal

  • Increasing storage densities of heat stores
  • Improving storage concepts for heat supply
  • Enhancing and optimization of sorption heat stores

Work of IKT

  • Selecting suitable adsorbens with high storage densities
  • Producing honeycombs with suit-able adsorbens and geometries

Partners

  • Fraunhofer ISE, Freiburg
  • Karlsruhe Institute for Technology (KIT)
  • University of Stuttgart
  • Technical University of Waldau
  • ZAE Bayern, Garching

Initial situation

  • Use of heat stores basing on zeolite and water
  • Using zeolitic pellets in fixed beds as sorption materials

Issue

  • Fixed beds suffer from high pressure losses when flown through
  • Formation of dust while use can damage system components or block pores of the adsorbend leading to worse soorption behavior

Approach

  • Zeolitic honeycombs do not suffer from this problems
  • Low pressure losses while flown through
  • No dust formation during service
  • Kinetics adjustable

Initial situation

  • Polyamides are brittle in dry condition
  • Impact modification with rubber

Problem

  • Loss of stiffness

Goal

  • Development of an impact modifier with low reduction of stiffness

Approach

  • Synthesis of a PA 6/polyether-block copolymer
  • Use as an impact modifier in PA 6 blends
  • Increase of the impact strenght
  • Low reduction of stiffness

Initial Situation

  • Simultaneous enhancement of both toughness and stiffness properties of PA 6 by means of ternary material systems
  • Potential of nanostructured filler materials for PA 6
  • Microstructure simulation of nanoscale composites (DFG-Gemeinschaftsprojekt mit IMWF, Univ. Stuttgart)

Problem

  • Incorporation of nanostructured filler materials
    by melt compounding
  • New filler/matrix-interaction
  • Identification of suitable morphologies
  • Development of simulation models (partner IMWF)

Approach

  • Improving toughness/ stiffness balance of polyamid 6
  • Application of a nanostructured polyamide 6/ polyether-blockcopolymer as impact modifier
  • Stiffness enhancement by incorporation of nanostructured organoclays
  • Correlation of morpohology with properties

Initial Situation

  • For extrusion of thick-walled pipes the melt viscosity of standard PA 66 is to low: „sagging“-effect
  • High molar mass / viscous PA 66 types are quite limited on the market and very expensive

Goal

  • Development of a concept to modify the molar mass of standard PA 66

Approach

  • rheological researches
  • Increasing of melt viscosity by a chain extension process with PA 66
  • Reactive extrusion process with a co-rotating twin-screw extruder
  • Maintenance of mechanical properties
Picture source: Rollen und Räder-Shop

Initial Situation

  • Cast polyamides have got high molecular weights and are used for highly stressed components
  • Waste volume is up to 30 %
  • Typically thermal recycling

Goal

  • Compounding cast polyamide waste into materials for extrusion or injection molding

Approach

  • Reactive compounding on a twin-screw extruder
  • Selection of suitable additives
  • Modification of the process
  • Tailoring the properties of the materials

Initial situation

  • Plastics are durable, versatile and can be produced in a cost-efficient way.
  • This becomes a disadvantage if plastics get into the environment in an uncontrolled and massive manner.
  • Major discharge paths are the so-called littering and secondary raw fertilizer.

Problem

  • Great durability and high resistance on land and in waters lead to accumulations - seas and soils become a sink

Approach

  • Development of new and existing methods for the identification and quantification of plastics in terrestrial systems (remote sensing, in situ ...).
  • Development of plastics with environmentally optimized degradability (primary biodegradation).
  • Investigation of the effect of plastic contamination on the meso- and micro-soil-fauna as well as the microbial degradability.
  • Investigation of social perception and patterns of behavior in dealing with plastics.

www.ensure-project.de

Initial Situation

  • microscopically small plastic particles enter the environment
  • Further fragmentation/degradation creates so-called secondary plastic particles
  • So-called primary plastic particles are already produced in microscopic size and e.g. used in peelings and toothpaste

Problem

  • Microorganisms in the sea, like water fleas take these particles in so that they can become part of the food chain

Goal

  • Investigation of the impact on marine organisms
  • Analysis of the behaviour of microscopic particles from bioplastics
source: M. Tosin et al., 2012

Initial Situation

  • Due to faulty consumer behaviour, plastic waste enters the environment and the sea.
  • Standard plastics such as PP, PE or PET are very resistant and virtually non-biodegradable (~ 1000 years).
  • Biodegradable plastics such as PLA are increasingly used in plastic applications.
  •  

Problem

  • So far the biodegradability is only certified for conditions on land.
  • degradation behaviour, i.e. degradation speed, tendency to fragmentation is not known in marine environment
  •  

Goal

  • Investigation of the degradation behaviour in different marine zones
  • Investigation of the resulting degradation products with regard to their toxic effect and the influence of typical additives

Initial Situation

  • Increase in thermal conductivity leads to anisotropic properties
  • In most cases, the thermal conductivity in the thickness direction is the lowest

Goal

  • Increase of thermal conductivity in thickness direction

Approach

  • Influencing the filling material orientation during processing
  • Alignment of fillers in thickness direction
  • Increase of thermal conductivity in thickness direction

Initial Situation

  • The critical strain is a plastic-suited design parameter.
  • The critical strain is the stain which occurs the first injury in the component.
  • The critical strain can currently only be determined very laboriously.

Goal

  • Development of a new, fast method for determining the critical strain.

Approach

  • Determination of the first injury
  • Use of sound emission analysis
  • Determination of critical strain in a short-time tensile test

Contact

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