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.
Authors:Miroslava Špérová, Petr Nasadil, Alena Průšová, and Jiří Kučerík
Degree of polymerization (DP) is the main factor playing role in the ageing of cellulosefibers. Processes of ageing are associated with the degradation of cellulose macromolecules, increasing the proportion of low
Authors:W. Esmail, A. Darwish, O. Ibrahim, and M. Abadir
Thermal analysis was used to investigate the effect of the addition of magnesium chloride hexahydrate as a fire retardant
to cellulosic fibers. The kinetics of the decomposition of the cellulosic material were first studied. The decomposition of
the dry salt was also investigated and three steps disclosed. Then, the fabrics were impregnated into salt solutions of different
concentrations and the loss in mass was followed by thermal analysis. The percent loss in mass was compared to that of pure
cellulosic fabric at different temperatures. It was found that there is an appreciable improvement in fire retardation at
a minimum percent add-on of the salt of 35%.
Authors:Hadi Fallah Moafi, Abdollah Fallah Shojaie, and Mohammad Ali Zanjanchi
The field of flame-retardancy of polymers has greatly developed and expanded during the last 20 years [ 1 ]. Most polymers and cellulosicfibers as organic materials are very sensitive to flame. Therefore, the
Authors:Maurizio Avella, Roberto Avolio, Irene Bonadies, Cosimo Carfagna, Maria Emanuela Errico, and Gennaro Gentile
of polymeric matrices, polyolefins are the most used to realize natural fiber reinforced (NFR) composites. Unless virgin cellulosefibers are mainly used as reinforcement in composites, in the last years recycled cellulose has been also proposed, in
Authors:Ivana Schwarzova, Nadezda Stevulova, Eva Singovszka, Eva Terpakova, and Jozef Junak
This article concerning natural cellulose fibers as reinforcement in composite materials in civil engineering. In this paper, the attention is given to industrial hemp specifically to the woody part of hemp plant called hemp hurds. The properties of natural fibers are mainly determined by the chemical and physical composition, such as structure of fibers.
The objective of presented research is to characterize raw and physically treated hemp fibers using Fourier transform infrared spectroscopy method. These natural fibers were used as filler into biocomposites and MgO-cement was used as alternative binder. Physico — mechanical properties (compressive strength, thermal conductivity, absorbability) of prepared composites were determined.
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.
Comparative investigations of new regenerated cellulosic fibers, bamboo viscose fiber and Tencel, together with conventional
viscose fibers have been carried out to explain the similarity and difference in their molecular and fine structure. The analyses
jointly using SEM, XRD and IR reveal that all the three fibers belong to cellulose II. Tencel consists of longer molecules
and has a greater degree of crystallinity, while bamboo viscose fiber has a lower degree of crystallinty. TG-DTG-DSC study
shows three fibers resemble in thermal behavior with a two-step decomposition mode. The first step is associated to water
desorption, suggesting that bamboo viscose fiber holds better water retention and release ability, the second a depolymerization
and decomposition of regenerated cellulose, indicating that Tencel is more thermally stable in this process than bamboo and
conventional viscose fiber.