@Article{OishiBoteRezeFerr:2017:StSuFu,
author = "Oishi, Silvia Sizuka and Botelho, Edson Cocchieri and Rezende,
Mirabel Cerqueira and Ferreira, Neidenei Gomes",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and
{Universidade Estadual Paulista (UNESP)} and {Universidade Federal
de S{\~a}o Paulo (UNIFESP)} and {Instituto Nacional de Pesquisas
Espaciais (INPE)}",
title = "Structural and surface functionality changes in reticulated
vitreous carbon produced from poly(furfuryl alcohol) with sodium
hydroxide additions",
journal = "Applied Surface Science",
year = "2017",
volume = "394",
pages = "87--97",
month = "Feb.",
keywords = "Poly(furfuryl alcohol), Reticulated vitreous carbon, Surface
functionalities, Microstructure, NaOH oxidation.",
abstract = "The use of sodium hydroxide to neutralize the acid catalyst
increases the storage life of poly(furfuryl alcohol) (PFA) resin
avoiding its continuous polymerization. In this work, a
concentrated sodium hydroxide solution (NaOH) was added directly
to the PFA resin in order to minimize the production of wastes
generated when PFA is washed with diluted basic solution. Thus,
different amounts of this concentrated basic solution were added
to the resin up to reaching pH values of around 3, 5, 7, and 9.
From these four types of modified PFA two sample sets of
reticulated vitreous carbon (RVC) were processed and heat treated
at two different temperatures (1000 and 1700 °C). A correlation
among cross-link density of PFA and RVC morphology, structural
ordering and surface functionalities was systematically studied
using Fourier transform infrared spectroscopy, scanning electron
microscopy, Raman spectroscopy, X-ray diffraction, and X-ray
photoelectron spectroscopy techniques. The PFA neutralization (pH
7) led to its higher polymerization degree, promoting a
crystallinity decrease on RVC treated at 1000 °C as well as its
highest percentages of carboxylic groups on surface. A NaOH excess
(pH 9) substantially increased the RVC oxygen content, but its
crystallinity remained similar to those for samples from pH 3 and
5 treated at 1000 °C, probably due to the reduced presence of
carboxylic group and the lower polymerization degree of its cured
resin. Samples with pH 3 and 5 heat treated at 1000 and 1700 °C
can be considered the most ordered which indicated that small
quantities of NaOH may be advantageous to minimize continuous
polymerization of PFA resin increasing its storage life and
improving RVC microstructure.",
doi = "10.1016/j.apsusc.2016.10.112",
url = "http://dx.doi.org/10.1016/j.apsusc.2016.10.112",
issn = "0169-4332",
language = "en",
targetfile = "Oishi_structural.pdf",
urlaccessdate = "02 maio 2024"
}