Study of the influence of the electron irradiation dose on the deformation of Mylar films taking into account the processes of destruction and crosslinking

Experimental studies of the dependence of the deformation [epsilon] on the dose of electron irradiation D taking into account the processes of destruction and crosslinking for films of the Mylar type have been carried out. It was obtained that the dependence of [epsilon] on D for the process of cross-linking is described by a linear and destruction by an exponential function

The rheology of highly concentrated emulsions stabilised with different surfactants

An investigation was performed into the effect of surfactants on the rheology of water-in-oil highly concentrated emulsions (HCE). The surfactants were oligomers of the PIBSA-type with different headgroups and low-molecular-weight sorbitan monooleate (SMO). The rheological properties of HCE are presented by flow curves with clearly expressed yield stress and dynamic modulus which does not depend on frequency but does on the amplitude of deformations. The changes in modulus and the yield stress depend on the nature of the headgroups as well as the addition of low molecular weight surfactant. It was shown that an increase in the surfactant concentration results in the decrease in the rheological parameters. This shows the significance of micellar structure on the rheological behaviour of HCE. The dependencies of elastic modulus as well as the yield stress on droplet size are deviated from scaling by Laplace pressure. This means that some additional arguments to explain the elasticity of “compressed” HCE emulsions should be included for comparison with the classical models based on the conception of increase in the surface area of droplets. Finally, it was found that the scaling of shear modulus with reciprocal squared droplet size fulfil the zero intercept condition for this variation.AEL Mining Service

IR studies of interfacial interaction of the succinic surfactants with different head groups in highly concentrated W/O emulsions

The interfacial properties of three succinic surfactants (PIBSA) with different hydrophilic end groups and sorbitan monooleate (SMO) in water-in-oil emulsions of the liquid explosive type were studied. The aqueous phase contained 40% of ammonium nitrate (AN). The trend in equilibrium interfacial tension was found to be PIBSA-MEA > PIBSA-UREA > PIBSA-MEA/SMO mixture > PIBSA-IMIDE > SMO, where MEA, UREA, IMIDE are amid/amide, urethane and imide end groups, respectively. The same trend was observed for the interfacial elastic modulus. The FTIR study revealed interactions between surfactant head groups and an AN solution. The interactions depend on the polarity of head groups determined by their chemical structure. The packing efficiency of the surfactants under study is also influenced by the chemical structure of head groups. Attempts to model the conformation of the surfactants at the interface were made. The investigation of mixed interfacial cover (PIBSA-MEA/SMO) showed that SMO remained at the interface reducing the interfacial tension at the W/O interface. It was also demonstrated that variation of the nature of head groups influences the rheological properties of emulsions. Bulk elasticity and yielding correlate with interfacial interaction characteristics

The rheology of binary mixtures of highly concentrated emulsions: Effect of droplet size ratio

Binary mixtures of highly concentrated emulsions (HCE) with three droplet size ratios and different compositions were prepared. It was found that by the proper selection of droplet size ratio and composition of binary mixtures, the shear modulus,viscosity,yield stress, and yield strain can be dropped lower than mixing rules and even primary HCE. This effect is similar to what is known for dispersions with volume fraction less than 0.7 but has not been described for HCE. For such formulations, the caged mechanism of droplets dynamics is not dominant due to the provided free volume that can be occupied by smaller droplets during flow. This is originated from the increase in maximum closest packing and thus more efficient spatial packing. By studying the scaling behavior of shear modulus and yield stress, the significance of interdroplet interaction was distinguished