The Use of Polymer Materials in the Composition of Asphalt Concrete

The research presented in the article shows the possibility of using some polymer materials in the composition of asphalt concrete. The analysis of scientific works in the field of asphalt concrete design shows the efficiency of using plastic waste to obtain asphalt concrete with specified physical, mechanical and operational properties. This technology allows not only to reduce the amount of accumulated plastic waste, but also to improve the condition of highways by increasing the strength of asphalt concrete. Polymers PP and LDPE were selected for the study. As PP samples, we used a nonwoven material used for the production of disposable medical masks, which is suitable for creating linear or dispersed reinforcement of asphalt concrete. LDPE was used as the second polymer sample. The obtained asphalt concrete samples differ from the traditional composition by their increased compressive strength at high temperatures while maintaining plasticity at low temperatures.

Mangala Polymer Flood Performance: Connecting the Dots Through in Situ Polymer Sampling

The paper describes the in-situ polymer sampling in Mangala which helped explain the performance of a large polymer flood in Mangala field in India. The Mangala field contains medium-gravity viscous crude oil. Notably, it is the largest polymer flood in India and 34% of the STOIIP has been produced in 11 years of production. Mangala was put on full field polymer flood in 2015, six years after the start of field production on water flood in 2009. Polymer flood added 93 million barrels above the anticipated water flood recovery in 6 years. Reservoir simulation models could replicate the initial Mangala polymer flood performance. However, the performance of the lower layers of Mangala (FM-3 and FM-4) continued to progressively deviate from modeling estimates. Equally importantly, the prediction of polymer breakthrough deviated significantly from modeling estimates. After 6 years and 0.7 pore volumes of polymer injection, it is apparent that field performance is equivalent to only 50-60% of the viscosity of the polymer injected at the surface. To better understand and quantify the nature and extent of polymer degradation it is necessary to gather representative down hole samples of polymer which has stayed in the reservoir conditions for a considerable length of time. Accelerated ageing studies in the lab showed HPAM can lose viscosity and precipitate after prolonged exposure to Mangala reservoir conditions with an increase in the degree of hydrolysis as the primary reason for the degradation. The concept of transfer function based on first order kinetics was used to extrapolate the laboratory results to Mangala reservoir temperatures. To test the hypothesis, a multi-disciplinary team implemented a plan to gather a representative polymer sample from the reservoir. The polymer sample had been in the reservoir for nearly 120 days and was captured in low shear and anaerobic conditions to minimize shear and oxidative degradation. The sample was tested for degree of hydrolysis by NMR method. The results confirmed that the level of hydrolysis of the injected HPAM did increase in the reservoir leading to lower viscosity and reduced lower amide concentration. Preliminary simulation studies using the concept of viscosity half-life were used to mimic the polymer degradation with time in the reservoir. The method is quite a simplistic representation of the thermal degradation, but it significantly improved the model's water cut predictions for lower layers and the full field polymer breakthrough predictions. The impact of polymer precipitation in the reservoir on the permeability is under study and it will drive the next phase of more detailed modeling.

D,L-polylactide degradation in biological media: experiment and model

The processes of changes in the surface morphology and internal structure, as well as the molecular mass distribution of amorphous D, L polylactides during their hydrolytic degradation in the presence of extra-germinal mesenchymal stem cells (MSCs) (ratschwart jelly umbilical cord) of the rat and their metabolic products have been studied. It was shown that the degradation of initially monolithic polymer samples in culture and conditioned media occurs almost identically. However, in a culture medium containing MSCs, this process is much more intense. This effect can be interpreted in terms of the influence of enzymes secreted by living cells, which diffuse from the surface into the polymer sample and accelerate its hydrolysis, entering into a catalytic reaction with the ether bonds of polylactide molecules. A mathematical model has been developed and verified that takes into account both non-catalytic and catalytic channels of hydrolysis, changes in the porosity of the polymer sample, diffusion of short-length oligomers, and adequately interprets the experimental results.

Direct comparison between chemisorption and physisorption: a study of poly(ethylene glycol) by means of single-molecule force spectroscopy

Chemisorption on an AFM-tip is the most promising protocol, if a functionalized polymer sample is available.

Friction of the Polymers - Experimental Results and Analytical Model

To determine the friction forces and friction coefficient in dry and lubricated conditions between steel and a triol crosslinked polyurethane, the authors developed a new experimental method consist in sliding of a steel cylinder on a plate polymer sample in the direction of the cylinder axis. By using this method the experiments were realized on a deformed path in the polymer sample by maintaining the same pressure distribution between the contact elements during the experiments. The experiments were realized with normal load between 1 N and 8 N and a cyclic linear speed having values between 1mm/s and 10 mm/s. Were determined the friction forces and friction coefficients in dry and lubricated contacts. An analytical model to evaluate the friction force in the cylinder – polymer contact surface has been developed and a good correlation with the experiments was obtained.