Ultrasonic treatment of polypropylene, polyamide 6, and their blends

Abstract

The mechanical and rheological properties of polypropylene (PP), polyamide 6 (PA6), and their blends treated by high-intensity ultrasound during extrusion were investigated. A lower head pressure was achieved in the extrusion of these thermoplastics. The mechanochemical and sonochemical effects of ultrasound led to simultaneous ionic condensation reactions and degradation in a homogeneous melt of PA6, with a prevailing effect of enhanced polycondensation reactions. The observed improvements in the mechanical properties of ultrasonically treated PA6 were attributed to condensation reactions, which yield a higher molecular weight, a higher crystallinity, and a more uniform crystal size distribution. At high ultrasound amplitudes, for PP, the degradation of polymer chains was observed with little deterioration of the mechanical properties. For ultrasonically treated PP/PA6 blends, a competition between the degradation and partial in situ compatibilization effect was found. At certain blend ratios, the tensile toughness and impact strength of the treated blends were almost double those of the untreated blends. However, full compatibilization was not achieved, possibly because of the low coupling selectivity of highly reactive radicals.

Thermal, sonochemical, and mechanical behaviors of single crystal [60]fullerene nanotubes

“…Cavitation that occurs adjacent to a solid sur- face leads to an asymmetric implosion with a microjet forming on the side of the bubble opposite the solid surface. These microjets are reported to move at speeds approaching 400 km/h creating enough force to deform or destroy molecules and materials including polymer like polypropylene and polyamide (Lin and Isayev, 2006). The [60]fullerene nanotubes prepared and studied here are not covalently attached to one another but rather held together by relatively weak van der Waals forces.…”

Properties of ultrasound-assisted blends of poly(ethylene terephthalate) with polycarbonate

“…The effects depend strongly on chemical structures consisting blend and ultrasonic amplitude irradiated. High intensity ultrasound effect was reported to enhance compatibility at short irradiation time in polymer blends [20][21][22][23].…”

Improvement of mechanical properties of poly(lactic acid) by integration of sepiolite nanoclays: effect of ultrasonication on clay dispersion

“…Ultrasounds (US), applied during the compounding of composites, have been experimentally used to ensure a good dispersion of the reinforcement in the matrix. 7 The better is the nanoclay dispersed, the more efficient is the reinforcement. This dispersion can be also improved avoiding the formation of undesired aggregates by applying ultrasonic waves throughout the melted polymer.…”