INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
CHEMICAL TREATMENT OF COTTON-CELLULOSE FIBERS AND THEIR IMPROVEMENT OF THEIR COMPATIBILITY WITH POLYCAPROLACTONE
Autor/es:
LEANDRO LUDUEÑA; MIRIAN CASCO; VERA ALVAREZ; ANALÍA VAZQUEZ
Lugar:
SALVADOR, BAHIA, BRAZIL
Reunión:
Congreso; INTERNATIONAL CONGRESS ON NATURAL FIBRES 2009; 2009
Resumen:
In this work, several surface treatments were carried out on cellulose fibers. They were:
alkaline-treatments (5, 10, 15 and 20 wt.% of NaOH and 10 wt.% of KOH);
acetylation (treatment with glacial acetic acid for 1 or 2 hours followed by
catalyzed acetic anhydride) and esterification (treatments with stearic
and lauric acids). The original and modified celluloses were characterized by
DSC (Differential Scanning Calorimetry), TGA (Thermogravimetric Analysis), FTIR
(Infrarred Spectroscopy), DRX (X-Ray Diffraction), SEM (Scanning Electron
Microscopy), water absorption test and contact angle measurements. The analysis
confirmed the decrease on crystallinity for alkaline treatment as a function of
NaOH concentration together with the change from cellulose I to cellulose II,
and the increase on the polarity and water absorption. Acetylated fibers showed
the higher change in crystallinity and a clear decrease on polarity degree and
water absorption. Esterification produced a slight increase on the
crystallinity without changing cellulose I whereas the water absorption
decrease and the polarity decreased until zero. All the results indicate that
this last treatment took place at the surface. The most compatible fibers were
used to prepare composites with 15 wt.% of them (and the untreated ones as
reference). Best properties were achieved with the 2 hours acetylated fibers
were a medium decrease on the polarity (good compatibility with the non polar
matrix) and slight reduction on the fiber aspect ratio was found. The
parameters from yield resistance mathematical models were in good agreement
with the experimental behaviour.