Use of ultrasound to determine variation of carbon dispersion in carbon black filled HDPE melts

Abstract

An ultrasonic technique was used to determine whether diVerences in the degree of dispersion of carbon ller in high density polyethylene (HDPE) melts could be identi ed. Ultrasonic transit time measurements were used to identify diVerences between three grades of HDPE with diVerent degrees of ller dispersion (designated high, medium and low dispersion). Tests were carried out on static melts (oV line) over a range of temperatures and pressures, and during extrusion (inline).Tests carried out on samples of static melt showed a signi cant increase in ultrasonic transit time for the poorly mixed ( low dispersion) sample, compared with the medium and high dispersion samples. DiVerences measured during oV line tests were not observed during extrusion tests.

A new extrusion head with integrated ultrasonic device and online process parameters measurements system — design and testing

“…Ultrasounds have been used in extrusion to analyze rheological and mechanical properties of different materials, i.e. polyethylenimine (PEI) [21], polyamide (PA) and polypropylene (PP) [15] comparing both mechanochemical and sonochemical methods, and to improve dispersion of nanoreinforcements into a polymeric matrix [22][23][24]. To optimize extrusion process conditions and obtain high purpose polymeric composites, it is important to characterize these rheological properties, that are related to dispersion state of the nanotubes, matrix orientation, and the interaction between nanotubes and polymeric chains [25].…”