Data/hora: 25/06/2024 00:26:26

Biblioteca(s): | Embrapa Agroenergia.
Tipo da produção científica: | Artigo em Periódico Indexado
Circulação/Nível: | A - 1
Data corrente: | 03/06/2019
Data da última atualização: | 18/11/2019
Autoria: | BREGADO, J. L.; SECCHI, A. R.; TAVARES, F. W.; RODRIGUES, D. de S.; GAMBETTA, R.
Afiliação: | Jurgen Lange Bregado, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil; Argimiro Resende Secchi, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil; Frederico Wanderley Tavares, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil; DASCIANA DE SOUSA RODRIGUES, CNPAE; ROSSANO GAMBETTA, CNPAE.
Título: | Amorphous paracrystalline structures from native crystalline cellulose: a molecular dynamics protocol.
Ano de publicação: | 2019
Fonte/Imprenta: | Fluid Phase Equilibria, v. 491, p.56-76, 2019.
Idioma: | Inglês
Conteúdo: | Cellulose amorphization is a suitable process that allows greater accessibility of cellulolytic enzymes to glycosidic bonds of cellulose, thus improving the yield of bioethanol obtained from lignocellulosic biomass. In a theoretical framework, we demonstrated the amorphization process of two cellulose allomorphs (Ia, Ib) using a new Molecular Dynamics (MD) protocol at high temperatures. At 700 K, in the high-temperature molten phase, these allomorphs showed the formation of structures with quite amorphous-shell and slightly paracrystalline-core (Am-Par structures) when the degree of polymerization is increased. Applying different characterization methods, we confirmed that Am-Par structures were similar at 700 K, as well as over a temperature ranging from 680 K to 380 K. This confirmation was based on low density of intra-chain hydrogen bonds (HBs), the absence of bands in the region of 3330 e3470 cm1 corresponding to such HBs in the simulated IR, low values of the lateral order index calculated from IR, Q4 and Q6 values close to zero, loss of long-range ordering observed in radial distribution functions, total destruction of crystal unit cell corroborated by X-ray diffraction, and similarity between probability density distribution of dihedral angle j with that computed for completely amorphous cellulose. Nonetheless, as revealed by X-ray diffraction results, this protocol seems to provide more crystalline structures starting from cellulose microfibrils having a polymerization degree higher than 10.
Palavras-Chave: | Amorphization; CHARMM force field; Crystallinity; Thermal treatment.
Thesaurus Nal: | Molecular dynamics.
Categoria do assunto: | --
Registro original: | Embrapa Agroenergia (CNPAE)
Exemplares: | CNPAE - (3467-1) - UPC - AP - DD -  -  -  - DIS