Evaluation of filler particle size within polymer matrix by optical spectroscopy

Abstract

Polymer composites with inorganic fi llers of different nature, concentration, particle size and shape were studied by optical spectroscopy (UV, visible, and IR ranges), optical and electron microscopy, and dynamic light scattering. An experiment to determine the size of the fi ller particles in aqueous suspension in the polymer matrix of a composite and directly in powders was conducted. It was shown that with increasing concentration aggregation of particles on drying an aqueous slurry occurs to a greater extent than for the fi ller in the polymer composite. It was demonstrated by examples that the optical spectroscopy can be successfully used for the analysis of sub-micron and micron sized fi ller particles in a polymer matrix or suspension.In recent years, in the fi eld of materials science new direction associated with production of nanopowders, examination of their properties and the creation of a variety of materials based on them [1] is intensively developed. Nanoparticle powders are characterized by unique properties, and their application is extremely broad. They are used as functional additives and activators in the polymerization, reaction modifi ers in composites, and other materials [1]. For example, the use of nanosized fi llers in the production of composites allows developing new classes of structural materials with improved operational parameters [2].It is well known [3] that the effi ciency of polymer modifi cation by dispersed particles depends on the characteristics of the fi ller such as particle size and shape, their volume fraction, particle size distribution, surface properties of the fi ller (surface area of the particle, its porosity, surface charge, the presence of functional groups on surface), the uniform distribution of the fi ller particles in the matrix volume, and others. The stability of the physical properties of the obtained materials is achieved by careful monitoring of the fractional composition of the fi ller. At the same time it is important not only the accuracy but also the speed of evaluation of the geometrical parameters of the fi ller particles. In practice, there are many ways to determine the particle size of a powder: sieving, sedimentation, and centrifugal methods, methods of optical and electron microscopy, dynamic light scattering method, the method of laser diffraction analysis [4][5][6].It should be noted that aggregation of nanofiller particles into larger formation occurs in the process of manufacturing the dispersion-fi lled polymer composites [7]. The process of aggregation of the particles affects the properties of composites. Aggregation of particles leads to a need to calculate the average particle diameter, since this parameter affects a value of the gap between the particles, which, for example, determines the level of structural strength and mechanical properties of the material. Therefore, monitoring of the concentration and size of aggregates of the fi ller particles, as well as their size distribution is very important in the stage of preparation ...

Spectroscopic Method for Evaluating the Quality of a Solvent in Gel-Forming Fibers

“…Рассеивающими частицами (загрязнителем) в ВМ, которое используется в качестве растворителя в отечественном методе гель-технологии, могут быть либо капли (имеем дело с эмульсией), либо твердые частицы (суспензия). И те, и другие системы удобно анализировать с помощью спектроскопического метода [4,5]. К спектроскопическим методам, основанным на рассеянии света, относятся также турбидиметрия и нефелометрия [6], но с помощью этих методов можно оценивать лишь степень мутности жидких объектов.…”

“…К спектроскопическим методам, основанным на рассеянии света, относятся также турбидиметрия и нефелометрия [6], но с помощью этих методов можно оценивать лишь степень мутности жидких объектов. Разрабатываемый нами спектроскопический метод, помимо этого, позволяет оценивать средний размер рассеивающих частиц и их распределение по размерам [3][4][5], их анизометрию и ориентацию [7].…”