Ultrasonic Processing of Polymers

Although the word processing is normally reserved for the method of manufacture of any finished article it is important to recognise that the word can also describe the preparation or synthesis of the material. Thus in the polymer field it can range from improved methods of synthesis of polymers with tailor made properties (see Section 5.5) to improved methods of dispersion or improved methods of extrusion. Typical technological uses are shown in Tab. 5.25. 

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Peshkovsky SL, Generalov MB, Kaufman IN (1971) Mehanika Polymerov 6 1097 Peshkovsky SL (1971) Ultrasonic intensification of polymer material extrusion processes. Summary of the thesis, Inst. Chem. Mach. Build., Moscow... 

Mathematical description of the process of polymer melting in the extrusion channel is complex when ultrasound is used. The description requires firstly, consideration of the mass flow of the polymer, knowledge of the flow characteristics of the melt, the temperature and pressure of extrusion, sizes of the channel and frequency of ultrasonic oscillations. Secondly, coefficient of swelling of the extrudate, effective viscosity of polymer, pressure of melt, and frequency of oscillations. 

Ultrasonic analysis of polymeric materials has been carried out from vanous viewpoints. One of present authors (KM) has performed prease measurements of ultrasonic velocity under tensile stress condition and utilized an acoustic emission (AE) phenomenon to investigate the formation of microscopic cracks and the fracturing process of polymers [1] Instrumental advancements have also enabled us to conduct rapid and even two-dimensional ultrasonic analysis of polymeric materials including composite materials [2,3],... 

Ultrasonication is a common tool for the preparation and processing of polymer nanoparticles. It is particularly effective in breaking up aggregates and in reducing the size and polydispersity of nanoparticles. The physical stability and in vivo distribution of nanoparticles are affected by their mean size, polydispersity, and surface charge density. Despite the widespread applications of ultrasonication in nanotechnology, its effects on chitosan nanoparticles are not well understood. 

Karelin YuM, Mazurenko YuS, Peshkovsky SL (1973) Device for ultrasonic effect upon flow of molten polymers. In Polymer equipment and processing of plastic masses, Tehnika, Kiev, P 31... 

Thus, macroradicals have been obtained by stretching fibers (20), deforming plastics by compression (37), ball mill grinding (11), freezing and grinding of polymer solutions (10), ultrasonic irradiation (I), mastication (19), dispersion in a microblender (25), and other mechanical techniques (36). Many reviews on the formation of macroradicals by degradative processes have also been published (5, 12,13,16, 33). 

Ultrasonic devulcanization, therefore, causes significant degradation of polymer chains. A simple model based on a purely topological consideration was proposed and simulation of the process was carried out. In the model they have assumed a breakup... 

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