Process Ultrasound:

Measurement of ultrasonic wave propagation through polymer melt is a non-intrusive, high speed process method of obtaining information on material parameters such as density, additive level and dispersion, and process variables such as temperature, pressure and flow rate. However, the application of ultrasonic measurement in processing industries has been limited by its high cost, the complexity of analysis and need for calibration (e.g. ultrasound transit time depends on density and bulk modulus, which are both temperature and pressure sensitive). Velocity of ultrasonic waves can be used as a measure of the consistency of the test medium, and attenuation of the signal can provide a measure of the loading and dispersion of additive particles. Ultrasound is of current interest to high level processors, compounders and technology suppliers.

An ongoing interaction with the internationally leading research group for ultrasonic monitoring technology (Canadian National Research Council, Montreal) has resulted in several joint publications around the application of novel sol-gel ultrasonic sensors developed in Canada.

Task 2 we will investigate the use of ultrasonic monitoring in a number of processing areas:

1. Micromoulding - this is a challenging process due to its small scale and high rates of strain and heat transfer encountered - sol-gel ultrasound sensors will be used to make non-invasive cavity measurements.
2. Fluid assisted injection moulding - to monitor the propagation of an injected fluid bubble (e,g, gas or water) through the previously injected polymer melt in an injection mould cavity.
3. Filled polymers - the use of ultrasound to monitor the particle size and dispersion level of fillers (including nanocomposities) in molten polymers in extrusion.
4. Rrecycled materials -material characterisation, monitoring process stability and batch variation.