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Despite its potential in the production of polymers from renewable sources, D-limonene faces difficulties in its polymerization, resulting in low monomer conversion and molar mass. In order to investigate the non-ideality inherent kinetics, this work explores different modeling strategies for D-limonene radical polymerization, using benzoyl peroxide as initiator. The starting model considered the classical approach for conventional radical polymerization. This model was then corrected by including reaction orders different from the unit. After an analysis and choice of the best model, computer simulations were compared with experimental results from literature, validating the chosen approach. It was found that the process is drastically influenced by chain transfer reactions, presenting a non-ideal behavior. Finally, an analysis of distinct reaction conditions provided information on monomer conversion, molar mass and polymer dispersity, which could guide future research in the synthesis optimization. Higher molar mass poly(limonene) were obtained by simultaneously reducing the monomer and initiator concentrations.

The components of a fluid mixture may segregate due to the Soret effect, a coupling phenomenon in which mass flux can be induced by a thermal gradient. In this work, we evaluate systematically the thermodiffusion of the CO 2 −H 2 O mixture, and the influence of the geothermal gradient on CO 2 segregation in deep saline aquifers in CO 2 storage. The eHeX method, a nonequilibrium molecular dynamics simulation approach, is judiciously selected to simulate the phenomenon. At 350 K, 400 bar, and CO 2 mole fraction of 0.02 (aquifer conditions), CO 2 accumulates on the cold side, and the thermal diffusion factor is close to 1 in a number of force fields. The lower the temperature, the higher is the separation and the thermal diffusion factor. In colder regions, water self-association is stronger, whereas the CO 2 −H 2 O cross-association and the CO 2 −CO 2 interactions enhance at higher temperatures. Thermodiffusion and gravitational segregation have opposite effects on CO 2 segregation. At typical subsurface conditions, the Soret effect is more pronounced than gravity segregation, and CO 2 concentrates in the top (colder region). Our work sets the stage to model the effect of electrolytes on CO 2 segregation in subsurface aquifers and other areas of interest.

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