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Chemistry

Single Crystal X-ray Crystallography

The department has Bruker Kappa Apex II X-ray Crystallography System for single crystal diffractometry. This instrument can be used to determine the atomic structure of a compound. A crystal of the compound is mounted in the instrument and exposed to x-rays. The crystal diffracts the x-rays into many specific directions. The intensity and angles of the diffracted beams can be used to calculate a 3 dimensional map of the electron densities in the crystal. From this the mean positions of the atoms and other information can be determined.

 

Nuclear Magnetic Resonance Spectroscopy

Bruker NMR

The department has a Bruker AvanceIII 400 Nuclear Magnetic Resonance (NMR) Spectrometer. This allows for the identification of a variety of chemical compounds using any nucleus that shows NMR activity. Compounds are placed in solution in a large magnetic field provided by a superconducting magnet. By applying a radio frequency signal and monitoring the sample's response, structural information about the compound can be obtained.

  

Electron Paramagnetic Resonance

Bruker EPR

Electron paramagnetic resonance (EPR), or electron spin resonance (ESR), spectroscopy is used to investigate chemical species that have one or more unpaired electrons. It is similar to NMR except that it is electron spin that are excited instead of atomic nuclei spin. The department uses a Bruker EMX Plus System.

  

High Performance Liquid Chromatography

Agilent HPLC

The department has a number of high performance liquid chromatography (HPLC) systems available. These are used to separate compounds for quantification. Separation is achieved by using a number of different analytical columns. A mobile phase is pumped through these columns and varying degrees of partitioning of the compounds between the mobile phase and the solid support allow for compound separation.

 

Brabender Plasticorder

Brabender Plasticorder

A Brabender Plasticorder is used to mix rubber compounds. The Brabender is connected to a computer to allow monitoring of mixing properties such as torque and temperature as well as control mixing parameters such as mixing speed.

 

Thermogravimetric Analyser

Thermogravimetric Analyser

The department possesses a TA 2050 Thermogravimetric Analyser. This device allows the monitoring of the mass of a sample to be followed as a function of temperature. From this information about the kinetics of chemical events inolving mass changes (e.g. oxidation, vaporization, polymer decompositions) can be obtained. Because decomposition temperatures are characteristic the device can be used for polymer identification as well as qunatification. The Physical and Polymer research group routinely uses this to determine filler content in vulcanizates. 

 

Rheometer

Rheometer

A Monsanto 100 Oscillating Disc Rheometer is used to measure the rate at which rubber compounds cure. The introduction of crosslinking during vulcanization significantly increases the stiffness of a rubber compound. The rheometer studies this by applying a shear force to a rubber sample at a particular temperature and measures the torque required to obtained a fixed degree of shear.

Tensile Tester

Tensiometer

An Instron 4411 Tensiometer with an Instron Long Travel Elastomeric Extensiometer attachment is used to measure the force required to stretch a polymeric sample to a particular degree. From this a measure of the force required to induce rupture can also be obtained. The department possesses both a 1 kN and a 5 kN load cell for elastomeric and plastic samples.

Molecular Modelling

 Molecular modelling

Computer facilities exist for at various levels, ranging from molecular mechanics through semi-empirical molecular orbital to density functional theory. Available software includes Spartan and PQS; the latter has parallel computation capability.

Other equipment

AA spectrometer

 

  • Atomic absorption (AA) spectroscopy
  • Capillary gas liquid chromatography (GLC)
  • Ion exchange chromotography
  • Electrometric techniques including amperometry, cyclic and stripping voltammetry, polarography and potentiometry
  • Infrared (IR) spectroscopy
  • Ozone generation
  • Photolysis and pressure reactors
  • PolarimetryThermal analysis including differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA)
  • Ultraviolet-visible (UV-VIS) spectroscopy