RESUMO

Petroleum-based plastics dominate everyday life, necessitating the exploration of natural polymers as alternatives. Starch, abundant and biodegradable, is a promising raw material. However, understanding the molecular mechanisms underlying starch plasticization has proven challenging. To address this, we employ molecular dynamics simulations, focusing on amylose as a model. Our comprehensive evaluation revealed that chain size affects solubility, temperature influenced diffusivity and elastic properties, and oleic acid expressed potential as an alternative plasticizer. Furthermore, blending glycerol or oleic acid with water suggested the enhancement amylose's elasticity. These findings contribute to the design of sustainable and improved biodegradable plastics.

Assuntos

Plásticos Biodegradáveis , Amido , Amilose , Ácido Oleico , Glicerol , Simulação de Dinâmica Molecular , Plásticos

RESUMO

The cation of the title solvated salt, C42H42N2P2 (2+)·2Br(-)·2CH2Cl2, lies on a crystallographic twofold rotation axis. The 1,2-di-amino-cyclo-hexane fragment has a chair conformation with two N atoms in a transoid conformation [N-C-C-N = 163.4 (2)°]. In the crystal, the cations are linked to the anions by N-H⋯Br and C-H⋯Br hydrogen bonds, forming a chain structure along the c axis. The di-chloro-methane mol-ecule takes part in the hydrogen-bond network through C-H⋯π and C-H⋯Br inter-actions.

RESUMO

Since the early work on Liesegang rings in gels, they have been a reference point for the study of pattern formation in chemical physics. Here we present a variant of the Liesegang experiment in gas phase, where ammonia and hydrochloric acid react within a glass tube producing a precipitate, which deposits along the tube wall producing a spatial pattern. With this apparently simple experiment a wide range of rich phenomenon can be observed due to the presence of convective flows and irregular dynamics reminiscent of turbulent behavior, for which precise measurements are scarce. In this first part of our work, we describe in detail the experimental setup, the method of data acquisition, the image processing, and the procedure used to obtain an intensity profile, which is representative of the amount of precipitate deposited at the tube walls. Special attention is devoted to the techniques rendering a data series reliable for statistical studies and model building, which may contribute to a characterization and understanding of the pattern formation phenomenon under consideration. As a first step in this direction, based on our data, we are able to show that the observed band pattern follows, with slight deviations, the spacing law encountered in common Liesegang rings, despite that the experimental conditions are very different. A further statistical correlation analysis of the data constitutes Paper II of this research.