Data/hora: 07/06/2024 17:17:25

Biblioteca(s): 	Embrapa Agroenergia.	
Data corrente: 	15/03/2019	
Data da última atualização: 	18/11/2019	
Autoria: 	VICTOR, P. A.; GONCALVES, S. B.; MACHADO, F.	
Afiliação: 	Priscilla Araújo Victor, UnB; SILVIA BELEM GONCALVES, CNPAE; Fabricio Machado, UnB.	
Título: 	Styrene/Lignin-Based polymeric composites obtained through a sequential Mass-Suspension polymerization process.	
Ano de publicação: 	2018	
Fonte/Imprenta: 	Journal of Polymers and the Environment, v. 26, p. 1755-1774, 2018.	
Idioma: 	Português	
Conteúdo: 	A modified sequential mass-suspension polymerization was employed to ensure adequate dispersion of lignin into the monomeric phase. Due to its complex macromolecular structure and low compatibility with styrene, eucalyptus wood-extracted lignin, via a modified Kraft method, was esterified with methacrylic anhydride to ensure organic phase homogeneity into the reaction medium. Infrared spectroscopy showed a decrease in the hydroxyl band, a characteristic of natural lignin (3200?3400 cm&#8722;1) and an increase in the characteristic ester band (1720?1740 cm&#8722;1) whereas nuclear magnetic resonance measurements exhibited intense peaks in the range from 1.7 to 2.05 ppm (?CH3) and 5.4 to 6.2 ppm (=CH2), related to methacrylic anhydride. Comparatively, the esterified lignin also displayed an increase of its glass transition temperature for 98 °C, related to natural lignin, whose Tg was determined to be equal to 91 °C. Styrene/lignin-based polymers exhibited higher average molar masses in comparison to the values observed for polystyrene synthesized with similar amounts of benzoyl peroxide, due to the ability of lignin to act as a free-radical scavenger. Composites obtained with styrene and natural or esterified lignin were successfully synthesized, presenting regular morphology and proper lignin dispersion. Based on a very simple polymerization system, it is possible to enhance the final properties of polystyrene through the incorporation of lignin, which represents an important platform for developing attractive polymeric materials from renewable resources.	
Palavras-Chave: 	Compósitos poliméricos; Polimerização sequencial; Polymer composites.	
Thesaurus Nal: 	Lignin; Styrene.	
Categoria do assunto: 	--	
URL: 	http://ainfo.cnptia.embrapa.br/digital/bitstream/item/194298/1/SILVIA-Victor2018-Article-StyreneLignin-BasedPolymericCo.pdf	
Registro original: 	Embrapa Agroenergia (CNPAE)	
Exemplares: 	CNPAE - (3441-1) - UPC - AP - DD -  -  -  - DIS