Theoretical study on the thermal degradation process of nylon 6 and polyhydroxybutyrate

This work presents the study of the thermal degradation process of two selected polymers: nylon 6 and polyhydroxybutyrate (PHB), representatives of polyamides and polyesters, frequently used nowadays. It is extremely important to specify optimal conditions that would allow a non-toxic and fast reprocessing of polymers in the plastic industry. The Density Functional Theory (DFT) method and a set of various computational details were applied to investigate the influence of the solvent presence and the rise of temperature on the thermodynamics of the degradation process. Obtained results were compared for both of the studied polymers, highlighting observed similarities. External conditions leading to the spontaneity of the nylon 6 thermal degradation process have been estimated. The results described in this paper can be useful in future research works investigating biodegradation conditions of the studied polymers

Effective Resource Allocation in Parallel Quantum-Chemical Calculations

Key factors affecting the parallel efficiency of archetypical quantum-chemical calculations are discussed. Effective load balancing schemes are proposed. Introduction of the memory affinity to the balancing process is shown to result in super-linear scaling

Path Integral Calculation of the Hydrogen/Deuterium Kinetic Isotope Effect in Monoamine Oxidase A-Catalyzed Decomposition of Benzylamine

Monoamine oxidase A (MAO A) is a well-known enzyme responsible for the oxidative deamination of several important monoaminergic neurotransmitters. The rate-limiting step of amine decomposition is hydride anion transfer from the substrate α–CH2 group to the N5 atom of the flavin cofactor moiety. In this work, we focus on MAO A-catalyzed benzylamine decomposition in order to elucidate nuclear quantum effects through the calculation of the hydrogen/deuterium (H/D) kinetic isotope effect. The rate-limiting step of the reaction was simulated using a multiscale approach at the empirical valence bond (EVB) level. We applied path integral quantization using the quantum classical path method (QCP) for the substrate benzylamine as well as the MAO cofactor flavin adenine dinucleotide. The calculated H/D kinetic isotope effect of 6.5 ± 1.4 is in reasonable agreement with the available experimental values