scholarly journals Numerical calculation of intermolecular bonds under the action of ultrasonic cavitation

2021 ◽  
Vol 2094 (2) ◽  
pp. 022074
Author(s):  
Roman N Golykh ◽  
Vladimir N Khmelev ◽  
Ivan A Manyakhin ◽  
Dmitry A Ilchenko ◽  
Vyacheslav D Minakov ◽  
...  

Abstract The linear model of macromolecules was proposed. Expression for probability of macromolecules breakup under ultrasonic cavitation action was obtained. The fractional composition and viscosity of uncured polymer were calculated. As a result of the calculations, it was evaluated that the cavitation-acoustic effect for a time of no more than 1 min at an vibration intensity of at least 6 W/cm2 and an initial viscosity of 0.2 Pa· s reduces the viscosity of polymers by at least 8 times. At the same time, it was theoretically revealed that the cavitation-acoustic effect is also capable of reducing the viscosity of polymers with an initial viscosity of more than 1 Pa·s up to 4 times.

Author(s):  
Vladimir N. Khmelev ◽  
Sergey N. Tsyganok ◽  
Yuriy M. Kuzovnikov ◽  
Vladislav A. Shakura ◽  
Maxim V. Khmelev ◽  
...  

Author(s):  
Р.Н. Голых ◽  
В.Н. Хмелёв ◽  
В.Д. Минаков ◽  
И.А. Маняхин ◽  
Д.А. Ильченко

Исследование механизма разрушения макромолекул под действием ультразвуковой кавитации представляет собой важную задачу. На сегодняшний день известен механизм разрушения макромолекул, основанный на том, что в условиях ультразвуковой кавитации создаются микроскопические зоны экстремально высоких давлений, в которых повышается вероятность актов разрыва макромолекулы. Разрыв происходит тогда и только тогда, когда относительная скорость при соударении макромолекул между собой превышает критическое значение. За счёт кавитации доля макромолекул, относительная скорость которых превышает критическое значение, увеличивается. В статье описана предложенная численная модель, которая предназначена для выявления молекулярных весов образуемых фрагментов при соударении. Предложен способ уменьшения количества неизвестных функций в 4 раза по сравнению с полной системой уравнений механики мономерных звеньев, основанный на симметрии в предлагаемой постановке задачи. Численно исследовано влияние взаимной ориентации макромолекул олигомеров на количество образуемых фрагментов. Полученные результаты могут служить ориентиром для развития макроскопической кинетической модели эволюции фракционного состава мономерных звеньев (эволюции концентраций мономерных звеньев различных типовых весов). The study of the mechanism of destruction of macromolecules under the action of ultrasonic cavitation is an important task. To date, the mechanism of destruction of macromolecules is known, based on the fact that microscopic zones of extremely high pressures are created in the conditions of ultrasonic cavitation, in which the probability of acts of rupture of the macromolecule increases. A rupture occurs if and only if the relative velocity when macromolecules collide with each other exceeds a critical value. Due to cavitation, the proportion of macromolecules whose relative velocity exceeds the critical value increases. The article describes the proposed numerical model, which is designed to identify the molecular weights of the fragments formed during collision. A method is proposed to reduce the number of unknown functions by 4 times compared to the complete system of equations of mechanics of monomeric links, based on symmetry in the proposed formulation of the problem. The effect of the mutual orientation of oligomer macromolecules on the number of fragments formed has been numerically investigated. The results obtained can serve as a guideline for the development of a macroscopic kinetic model of the evolution of the fractional composition of monomeric units (the evolution of concentrations of monomeric units of various typical weights).


Author(s):  
C. E. Cluthe ◽  
G. G. Cocks

Aqueous solutions of a 1 weight-per cent poly (ethylene oxide) (PEO) were degassed under vacuum, transferred to a parallel plate viscometer under a nitrogen gas blanket, and exposed to Co60 gamma radiation. The Co60 source was rated at 4000 curies, and the dose ratewas 3.8x105 rads/hr. The poly (ethylene oxide) employed in the irradiations had an initial viscosity average molecular weight of 2.1 x 106.The solutions were gelled by a free radical reaction with dosages ranging from 5x104 rads to 4.8x106 rads.


2010 ◽  
Author(s):  
Thomas Ferris ◽  
Kiana Stringfield ◽  
Nadine Sarter

2010 ◽  
Vol 41 (02) ◽  
Author(s):  
J Möhring ◽  
D Coropceanu ◽  
F Möller ◽  
S Wolff ◽  
R Boor ◽  
...  

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