Authors:F. Pruneda, J. J. Suñol, F. Andreu-Mateu, and X. Colom
Summary Nitrile butadiene rubber (NBR) and NBR/PVC blends were produced using 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ) or not as antioxidant. Controlled ozone degradation was performed in several samples. Thermal, compositional and morphological analysis was performed by means of differential scanning calorimetry, thermogravimetry, chemical analysis and scanning electron microscopy. Thermogravimetry analysis shows four mass loss processes related to plastizicer, complex rubber degradation and metallic oxides and other additives. In NBR (NBR/PVC blends) the onset temperature of the first degradation process varies between 227-231°C (259-262°C) and the apparent activation energy between 26 and 36 kJ mol-1 (36-57 kJ mol-1), the NBR/PVC samples non degraded presents the higher thermal stability.
Authors:J. Suñol, J. Saurina, F. Carrasco, X. Colom, and F. Carrillo
Lyocell, modal and
viscose fibers were subjected to mercerization or to solar degradation. The
ulterior thermal degradation was analyzed by means of differential scanning
calorimetry (DSC). Thermal analysis shows wide exothermic processes that began
between 250 and 300C corresponding to the main thermal degradation and
are associated to a depolymerization and decomposition of the regenerated
cellulose. Thermal degradation was analyzed as a function of concentration
and time. Lyocell fiber is the most stable under thermal degradation conditions.
Furthermore, mercerized samples are initially more degraded and present a
lower thermal stability.
Authors:F. Carrillo, B. Defays, X. Colom, J. Suñol, and M. López-Mesas
In the present work Lyocell fibers were subjected to graft copolymerization of poly-N-isopropylacrylamide (pNIPAAm) thermosensitive
polymer. The thermal degradation and stability of lyocell/pNIPAAm copolymers gels were characterized by differential scanning
calorimetry (DSC) and thermogravimetric analysis (TG). pNIPAAm/lyocell copolymers are thermally stable and more resistant
to temperature than lyocell fibres. Thermal characterization was analyzed as a function of percentage by mass of the pNIPAAm
grafted. It has been shown that for pNIPAAm/lyocell copolymers, degradation occurs at higher temperature when increasing the
degree of grafting.
Authors:J. J. Suñol, D. Miralpeix, J. Saurina, F. Carrillo, and X. Colom
Summary New regenerated cellulose fibers were developed during the last decades as environmentally friendly systems. In this work, three fibers: lyocell, modal and viscose were subjected to an enzymatic treatment. Likewise, different lyocell fibers were washed in a Na2CO3 solution under severe conditions. Analysis was performed by means of differential scanning calorimetry, thermogravimetry and scanning electron microscopy. In all samples, at low temperature, water desorption was detected. Furthermore, thermal analysis shows wide exothermic processes that began between 250 and 300°C corresponding to the main thermal degradation and it is associated to a depolymerization and decomposition of the regenerated cellulose. It is accompanied with mass more than 60% mass loss. Kinetic analysis was performed and activation energy values 152-202 kJ mol-1 of the main degradation process are in agreement with literature values of cellulose samples.