Active Filler Particles Research Articles

The Influence of the Size of Active Filler Particles (Ionite KU 2-8 in Nickel Form) on the Moisture Sensitivity of a Touch Film

The Influence of the Size of Active Filler Particles (Ionite KU 2-8 in Nickel Form) on the Moisture Sensitivity of a Touch Film

In-mouth breakdown behaviour and sensory perception of emulsion gels containing active or inactive filler particles loaded with capsaicinoids

This work investigated the effects of active versus inactive filler particles on the structure, rheological properties, in vivo oral breakdown behaviour and sensory perception of emulsion gels containing capsaicinoids (CAPs). CAP-loaded Tween-80-coated emulsion droplets were not bound with the whey protein matrix (i.e. emulsion gels containing inactive filler particles) and appeared to be flocculated and inhomogeneously distributed in the gel matrix, which led to drastically decreased mechanical gel strength. CAP-loaded Tween 80 emulsion gels had significantly lower fracture stress and fracture stain than CAP-loaded whey protein emulsion gels (emulsion gels containing active filler particles), indicating that they were more easily broken down into small fragments in the mouth at small deformations with less chewing (i.e. lower fracture energy, fewer chewing cycles and shorter duration). During mastication, large amounts of oil droplets were released from the gel matrix of the CAP-loaded Tween 80 emulsion gels, which also contributed to their significantly smaller bolus particle size. The released oil droplets from the CAP-loaded Tween 80 emulsion gels facilitated bolus formation through lubrication and decreased the chewing cycles. A higher degree of fragmentation led to greater surface exposure (i.e. new surface area created) during mastication, and therefore to higher mouth burn perception. The large amounts of oil droplets released from the gel matrix during mastication and the inhomogeneous distribution of the oil droplets because of flocculation of the CAP-loaded Tween 80 emulsion gels also contributed to their higher mouth burn perception. The oral processing behaviour of the CAP-loaded emulsion gels and the sensory perception of capsaicinoids could be tuned by manipulating the droplet-matrix interactions and the gel structure.

Quantum mechanics simulation and experimental study of adhesive interaction and aggregation of carbon-silicate nanoparticles—reinforcing fillers of polymer composites

Nanoparticles are widely used as polymer composite-reinforcing additives—fillers. Understanding the interaction mechanisms and regularities responsible for nanoparticle aggregation is of great significance for elucidating the nature of reinforcing of polymer composites. The paper reports on quantum mechanics calculations and full-scale experimental study of adhesive interaction of carbon and silicate adsorption complexes (nanomodels of active filler particles of polymer composites). The quantum mechanics approach allowed describing the adhesive properties of particle aggregates reasoning from nanoscopic structure of their surface. The quantum mechanics data were checked for adequacy on schungite—a natural mineral containing carbon and silicate. Schungite microparticles were milled to nanosizes by colloidal grinding in various disperse liquid media (alcohol, acetone, water) and the structure and properties of aggregated schungite micro- and nanoparticles were studied; fractal analysis of their surface was performed. It is found that smaller aggregates of silicate and carbon particles with higher surface fractal dimension are formed in colloidal grinding with small molecular sizes of disperse media (in our case, ethanol or methanol) and this agrees with the data predicted by quantum mechanics calculations.

Viscoelastic properties of acid milk gel as affected by fat nature at low level

Abstract The viscoelastic properties of acid milk gels containing small amounts of different fats were investigated. Skim milk was reconstituted from ultra low-heat skim milk powder and emulsions made with 2% (v/v) sunflower oil, olive oil, groundnut oil, or anhydrous milk fat using a pressure homogenizer. Acidification at 20 °C for 14 h to pH ∼4.6 was achieved by adding glucono- δ -lactone to the emulsion. Stress relaxation testing enabled determination of the firmness and the solid-like properties, i.e., elasticity. Regardless of the physical state of the fat, emulsion gels exhibited higher firmness than fat-free gels, despite the low fat level used. The firmness of the gels containing this small quantity of fat was more sensitive to temperature than was the firmness of fat-free gels. The relaxation time was higher in the presence of fat crystals. Modifications in the rheological properties of gels containing fat were attributed to fat droplets acting as active filler particles.

Filler effects of oil droplets on the rheology of heat-set emulsion gels prepared with egg yolk and egg yolk fractions

Hen egg yolk is a traditional ingredient used in a wide variety of food emulsions, especially fluid sauces. Industrial processing of these sauces generally involves heat treatments in order to pasteurise or sterilise them. These heat treatments may cause undesired gelation of the emulsion, because egg yolk proteins are particularly thermosensitive. Heat gelation of oil-in-water emulsions prepared with egg yolk may differ from that of egg yolk solutions, because of the influence of oil droplets on network formation. In this study, we investigated the influence of oil droplets on the gelation of oil-in-water emulsions made with yolk. We studied three pH values: 3.0, 5.0 and 7.0 with a constant NaCl concentration: 0.55 M. Oil droplet size was controlled after emulsification, gelation of solutions and emulsions was monitored in situ by coupling heating with recording viscoelastic properties, and transmission electron microscopy was conducted in heat-set emulsion gels. In an attempt to target the proteins that impose the kinetic of gelation of egg yolk, we repeated the experiment with plasma and granules, the main fractions of yolk. In situ rheology showed that, in our experimental conditions [especially oil volume fraction (0.3) and oil droplet size ( d3.2=1 μm)], emulsions made with yolk and plasma have a similar gelation process with oil droplets acting as inactive fillers. Furthermore, transmission electron microscopy showed similar network characteristics between heated emulsions made with yolk and plasma. Moreover, we demonstrated that acidic conditions provided the fastest gelation of yolk solutions and emulsions. On the other hand, in emulsions prepared with granules, oil droplets behaved as active filler particles and reinforced the gel strength.

Near Net Shape Manufacturing of Polymer Derived Ceramics

Pyrolytic conversion of preceramic polymers loaded with active filler particles offers the possibility of near net shape manufacturing of bulk ceramic components from polymers. Active fillers based on elements (B, Si, Al, Ti, Mo, etc.), intermetallics (CrSi2, MoSi2, etc.) or ceramic compounds (AlN, B4C, etc.) which react with the solid and gaseous decomposition products of the preceramic polymer (polysilane, -carbosilane, -silazane, siloxane, etc.) during pyrolysis may form carbide, nitride or oxide reaction products in the polymer derived amorphous or microcrystalline matrix. The main effects of the active fillers are to form a stabilizing network of the filler reaction products, increase ceramic yield of the polymer, and to provide internal surface for material transport during polymer decomposition reactions. Thus, dimensional change, porosity formation as well as material properties can be tailored in a wide range by combination of a variety of polymers, fillers and reaction atmospheres.

VISCOELASTIC PROPERTIES OF HEAT‐SET WHEY PROTEIN EMULSION GELS

ABSTRACTThe viscoelastic properties of heat‐set whey protein gels and whey protein‐stabilized emulsion gels have been studied using the dynamic oscillatory rheometry technique. The storage modulus was monitored and analysed for pure protein gels and emulsion gels over a wide range of protein concentrations. The dependence of storage modulus on protein concentration is different for gels of low and high modulus. At low protein concentrations, the increase of storage modulus is much more sensitive to the increase of protein concentration. The protein‐coated oil droplets behave as active filler particles and dramatically enhance the gel strength. The effect of the oil volume fraction on the rheology has been investigated for emulsion gels containing 11 vol. %, 20 vol. % and 45 vol. % Trisun oil. The formula of van der Poel fails to describe the experimental results. This is attributed to the strongly flocculated state of the emulsion system.

The effect of slow physical relaxation processes on the properties of elastomers over a wide temperature range

The relaxation properties of crosslinked elastomers and of rubbers based on SKMS-10 SKN-18 + SKN-16 and SKN-40, modified with surface-active agents were investigated by relaxation spectrometry. Not only the rapid, but also the slow physical relaxation processes, related to fluctuational decomposition of the microblocks of supersegmental and supermolecular structures (λ-processes) and to the thermal mobility of the active filler particles (ϕ-processes) had a significant effect on such elastomer properties as capability for molecular orientation and durability to multiple strain at temperature of T> T g, on maintaining high-elasticity properties at low temperatures etc. Surface active agents are efficacious modifiers, affecting the time and energy of activation of λ-and ϕ-relaxation processes, the effect of the surfactants being increased with a temperature decrease. A scheme for predicting these processes in a low temperature region was developed and the temperature boundaries for reliable prediction of relaxation processes were determined.

The effect of the filler on relaxational transitions in butadiene-methylstyrene copolymer

Ten relaxational transitions have been found above the glass transition temperature ( T g) in butadiene-methylstyrene copolymer, hlled with carbon black: λ-transitions related to the presence of macro-blocks of supersegmental and supermolecular structure of various nature, δ S and δ C transitions related to rearrangement and rupture of chemical SS and CC cross links and the ϕ transition related to the rearrangement of the active filler particles. The introduction of the filler decreases the contribution of λ and δ C transitions. A correlation is observed between transition temperatures calculated from relaxation time spectra (static method) and those determined from internal friction spectra (dynamic method).

Relaxational ϕ-transition in filled polymers and molecular mobility of active filler particles

A theory of the ϕ-process of relaxation in filled elastomers is proposed based on certain notions of the thermal motion of the filler particles. From the results of relaxational spectrometry for the elastomers (butadiene-styrene and isoprene) filled with active commercial carbon PM-100 the linear dimensions of the filler particles are calculated. The results agree with the direct determination of the filler particle size in the electron microscope.

Relaxation properties of filled isoprene elastomers

A series of dynamic and quasi-static methods enabled seven relaxation transitions to be detected in filled, crosslinked isoprene elastomers above the glass temperature; two of these, the α ′ and ϕ process are due to the presence in the elastomer of an active filler and depends on the type of this filler. They are explained by the segmental mobility in adsorption layers of the polymer on an active filler ( α ′-process) and the mobility of active filler particles (ϕ-process). With an increase of the degree of crosslinking in the filler—technical carbon—the activation energy of both processes of relaxation increases. Oxidation of technical carbon of a low degree of crosslinking also increases the activation energy of these processes.