Stability of Chemically Degraded Friction Reducers and Their Relationship to Regain Conductivity

Previously, it was shown that zeta potential could be used as a metric to determine friction reducer (FR) performance. Specifically, the extent of and how quickly the FR reaches peak friction reduction in source water. A correlation postulated from the previous work is zeta potentials relationship to an FR's stability during mechanical or chemical degradation. In other words, can zeta potential be used as a metric to determine the extent of polymer breaking and can this relationship be translated to regained conductivity? This paper describes a laboratory study of zeta potential measurements to track breaker reaction rates, stability of broken polymer dispersions, and the relationship between chemical degradation of FRs and regained conductivity. The approach of this investigation involves measuring zeta potential of frac fluids formulated using anionic and cationic FRs with varying types and concentrations of breakers at different temperatures and times. These metrics are then correlated with regain conductivity. A quantitative relationship exists between zeta potential, fluid rheology, and regain conductivity. Zeta potential evaluation of degraded FR's in frac fluids correlate to performance in regain conductivity testing. These measurements can expedite the selection of chemical breakers with respect to performance. Zeta potential measurements of degraded FR are indicative of broken FR dispersion stability which has impact on regain conductivity. Tracking behavior of cationic FR's using zeta potential reveals the materials can become anionic with time and temperature and become susceptible to agglomeration with iron. Zeta potential measurements can be used during a chemical breaker selection process as a viable supplement to industry standard tests for assessing the comparative effectiveness of chemical breakers in frac fluids.

Directed Assembly of Particles for Additive Manufacturing of Particle-Polymer Composites

Particle-polymer dispersions are ubiquitous in additive manufacturing (AM), where they are used as inks to create composite materials with applications to wearable sensors, energy storage materials, and actuation elements. It has been observed that directional alignment of the particle phase in the polymer dispersion can imbue the resulting composite material with enhanced mechanical, electrical, thermal or optical properties. Thus, external field-driven particle alignment during the AM process is one approach to tailoring the properties of composites for end-use applications. This review article provides an overview of externally directed field mechanisms (e.g., electric, magnetic, and acoustic) that are used for particle alignment. Illustrative examples from the AM literature show how these mechanisms are used to create structured composites with unique properties that can only be achieved through alignment. This article closes with a discussion of how particle distribution (i.e., microstructure) affects mechanical properties. A fundamental description of particle phase transport in polymers could lead to the development of AM process control for particle-polymer composite fabrication. This would ultimately create opportunities to explore the fundamental impact that alignment has on particle-polymer composite properties, which opens up the possibility of tailoring these materials for specific applications.

ДОСЛІДЖЕННЯ ВПЛИВУ СТИРОЛ-АКРИЛОВИХ ПОЛІМЕРІВ НА ФІЗИКО-МЕХАНІЧНІ І ГІГІЄНІЧНІ ВЛАСТИВОСТІ БАВОВНЯНОЇ ТКАНИНИ

The purpose of the work is to study the effect of styrene-acrylic polymer coatings on the change in physical, mechanical and hygienic properties of cotton fabric. Aqueous dispersions of styrene-acrylic polymers (Lacrytex 640, Akratam AS 02.1, Tubifast AS 4010) were selected as the object of study. The processing of cotton fabric was carried out by the method of impregnation with varying a concentration of the studied polymers in finishing bath from 50 g/l to 150 g/l, followed by drying and heat setting. Standardized methods for studying the properties of textile materials were applied. The effect of polymer coatings on the physical and mechanical properties of cotton fabric was evaluated by the indicators of weight gain, thickness and rigidity. The hygienic properties of treated cotton fabric were characterized by hygroscopicity and breathability. The paper presents the results of a study of the dependence of physical, mechanical and hygienic properties of cotton fabric on the type and concentration of styrene-acrylic dispersions used. According to the results of the experiment, it was found that the acrylic copolymer Lacrytex 640 increases the elastic properties of treated fabric in the entire concentration range studied. It was determined that the greatest decrease in air permeability is typical for fabric samples coated on the basis of Akratam AS 02.1 dispersion. The hygroscopicity of cotton textile material with an increase in a concentration of the studied styrene-acrylic polymer dispersions from 50 g/l to 100 g/l decreases slightly (by 2%). It is proved that the styrene-acrylic copolymer Tubifast AS 4010 due to the formation of highly elastic film provides a soft handle and high hygienic properties of cotton fabric. The obtained experimental results are of practical value in the development of new finishing compositions for textile materials.

A Surprisingly Gentle Approach to Cavity Containing Spherocylindrical Microparticles from Ordinary Polymer Dispersions in Flow

Herein, we demonstrate a facile approach to fully transform spherical polymeric microparticles to elongated spherocylinders containing an internal cavity under ambient and mild stirring conditions. Critical to the process is...