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Polymer, fibre and bulk characterisation equipment


Polymer chemistry and synthesis laboratory

Here is where we synthesise highly porous polymers from emulsion templates, micro(hydro)gels, responsive crosslinked polymers and modify polymer surfaces and carbon nanotubes.


Polymer Characterisation

GPC (Gel permeation chromatography) with triple detection system

for the characterisation of the molecular weight (distribution) of water-soluble polymers.

Mechanical Characterisation of Materials

Single Fibre Pull-Out Testing Machine 

Our single fibre pull-out machibe was designed by BAM Berlin. The device uses a piezoactuator (with a displacement resultion of a few nanometres) and a piezo force transducer (with a resolution of 0.1 mN). The device itself is built on a very stiff frame in order tominimize problems with energy storage and thermal expansion. A microscope is fitted to allow optical observations during testing. We use this instrument mainly to determine the:

·         Strength and modulus of thin reinforcing fibres, incl. strength dependence of fibres at short gauge lengths

·         Adhesion and friction properties of single fibre composites


Mechanical Testing (3 and 4 point Bending, Compression, Tension)*

We use this device for the mechanical characterisation of small composite specimen as well as macroporous polymer foams (polyHIPEs)

*Equipment housed in the Analytical Services Laboratory (mainly funded by the Department of Chemical Engineering and partially by PaCE)


Moisture Uptake Behaviour

Dynamic vapour sorption (DVS)

DVS allows automated, rapid and accurate gravimetric measurements of moisture and organic vapor uptake in solid materials (e.g., polymers, composites and porous materials) over a wide temperature range using dynamic environment control and ultra-sensitive recording microbalance with resolution of ~0.1μg. The ability to work with very small sample sizes combined with dynamic vapour flows reduces the time to measure moisture sorption isotherms from weeks or months to hours or days. This equipment is useful for accurately assessing water uptake in porous media, where it obviates artifacts caused by trapped or retained water in the pore structure. Studying the time dependent moisture uptake is of particular relevance for green composites and biodegradable biomedical materials.

*Equipment co-owned and partially funded by the Department of Chemical Engineering


Viscoelastic and rheological properties

Rheometer

This equipment assesses the drag caused by relative motion of the fluid and a surface, which is a measure of the viscosity.

Capillary Rheometer

Measures liquid, suspension or slurry flows in response to applied forces. Unlike a viscometer, it is used for fluids which cannot be defined by a single value of viscosity and therefore require more parameters to be set and measured. Liquid is forced through a tube of constant cross-section and precisely known dimensions under conditions of laminar flow. Either the flow-rate or the pressure drop are fixed and the other measured. Knowing the dimensions, the flow-rate can be converted into a value for the shear rate and the pressure drop into a value for the shear stress. Varying the pressure or flow allows a flow curve to be determined.


Characterisation of Porous Media

Simultaneous measurement of:

·         Pore volume distribution

·         Limiting pore throat di a meter

·         Permeability distribution

·         Electrical resitivity of a sample during mercury penetration

The pore volume distributionlimiting pore throat diameterpermeability distribution and electrical conductivity of porous materials can be meas ured simult aneo usly following the penet ration of por es with merc ury. Porous samples are placed in the sample cell and t he mercury is forced into pores, since mercury is non-wetting the pressure applied to the mercury can be used to determine the diameter of the pores being filled. Incremental increases in the applied pressure result in the determination of the pore volume distribution. Application of a pressure gradient across the sample induces mercury flow through pores of a specific diameter and a permeability distribution can be developed. The applied pressure corresponding to the onset of mercury flow indicates the limiting pore throat size. For an electrically non-conducting medium, the measured electrical conductivity is governed by that of mercury and is analogous to the process of diffusion through the penetrated pores.

How it works:


University of Vienna | Universitätsring 1 | 1010 Vienna | T +43-1-4277-0