This Polymer Characterisation Research Technology Platform contains a number of instruments divided between several locations belonging to either Chemistry or Research Technology Platforms. In some cases, the instrumentation belongs to Chemistry but is run and maintained by the RTP.
Instrumentation and Application
DSC the most important effects that this can analyse are melting point, melting range and melting behaviour. DSC is also used to determine the heat of fusion, glass transition, oxidation stability and specific heat capacity up to 600°C.
TGA measures mass changes. The main applications of TGA are content determination, thermal stability, decomposition kinetics, and composition analysis.
TGA-DSC is a combined technique instrument where the mass measurement is of high accuracy but DSC is of low sensitivity compared to dedicated instrument ambient to 1000°C.
TGA-DSC mass spectrometer same as TGA-DSC but with evolved gas analysis with sensitivity of ambient to 1500°C.
TMA is normally used to study the expansion, softening or shrinkage of materials and the glass transition. Its unique application is the determination of the Coefficient of Thermal expansion, or CTE -150 to 500°C
DMA is used to measure the mechanical behaviour and properties of materials. This includes the modulus and damping behaviour. It is the most sensitive method for measuring and characterizing glass transitions, Tg and sub-Tg relaxations, in materials ambient to 400°C.
Rheometer is used for complex flow and deformation behaviour relative to temperature.
GPC/SEC Size separation technique most commonly used for measuring molecular weights of polymers relatively to know standards (such as PS or PMMA). With advanced analysis can be used for non-relative molecular weight measurement and structural information, such as branching.
AF4 Separates based on size by a different mechanism to GPC. Combined with light scattering to measure molecular sizes of materials such as nano-particles and colloids. Typically run in aqueous buffer.
DLS Used to measure particle size of batch solutions by correlation of Brownian motion. Typicaly for sub-micron particle sizes.
Laser Diffraction Measures particle size by diffraction of laser light. Typically run in water and used for particles in micron range.
Mechanical Tester Is often used to measure the mechanical properties of materials via compression or tensile testing. This can give yield strength, stress/strain and Young’s moduli.
Drop Shape Analyser is used to measure either a surface or a droplet of liquid. This can get contact angle measurements, hydrophilicity/hydrophobicity, surface energy or interfacial tension.
HPLC separates materials by interactive chromatography. The analyte elutes as a function of relative interaction with mobile and stationary phase to separate and quantify materials. Can be run as normal phase or reverse phase (a notation of whether the station phase or mobile phase are the polar phase or not).
GC separates as a similar principle to HPLC where the mobile phase is now gas rather than liquid. There is also the further dimension of volatility to separate samples, rendering it more common for low molecular weight, highly volatile materials. This is often used for checking purity of materials or following monomer consumption for kinetics. Is considered to be quantitative when used appropriately.
GCMS separates as GC with a mass spec as the detector. This allows for chemical identification of analytes. Very rarely can it be quantitative - Is often combined with GCFID for this purpose.
FTIR uses the relatively frequencies of bonds within a material to elucidate which bonds are present. This can be used to follow chemical changes in a material and also for chemical identification when compared to database of known materials.
ESI-MS is a mass spec technique and therefore not appropriate for high molecular weight polymers. Separates by mass over charge and can give explicit mass and mass distribution information. Can be couple to Thermo Fisher HPLC to give separation of mixtures before mass analysis.
If you would like to know more about these instruments, their applications or how to access them, please contact d dot lester at warwick dot ac dot uk
Agilent GPC/SEC and Post Nova Field Flow Fractionation (AF4):
9 instruments in a variety of solvents with multi-detector capabilities. If required these can be transferred into alternative solvent systems.
Agilent Infinity II BioMDS SEC - Size separation and sizing
Post Nova AF4 - Size separation and sizing