engleski

Thermal behaviour of cellulose acetate based bio composite materials prepared from underutilized wood species

Other to its well defined use as a material for filtration, desalination and medical dialysis, cellulose acetate (CA) can be used as polymer matrix of solvent cast bio composite materials. In such cases CA matrix can be filled with various types of organic and inorganic fillers, which more or less define the materials properties. If CA based bio composite materials are prepared using various types of chemically similar fillers (e.g. holocellulose, cellulose allomorphs, etc.), and if the raw material for the preparation of CA and fillers is of the same lignocellulosic origin, the problem of filler-matrix incompatibility could be overcome. As CA and aforementioned fillers can be prepared from almost any type of cellulosic material, the use of somewhat underutilized wood species should result in preparation of higher added value bio composite materials with satisfactory properties. Therefore, in this work we have prepared bio composite materials with CA based matrix filled with holocellulose, alpha cellulose and crude Kürschner-Hoffer cellulose, using white willow (Salix alba) wood meal as raw material for both the matrix and filler preparation. Analysis of obtained CA was performed by means of Fourier transform infrared spectroscopy and by determining the acetyl content and degree of substitution (Španić et al. 2015). Bio composite materials were prepared in form of solvent cast thin films and their thermal behaviour was determined by means of differential scanning calorimetry (DSC). Obtained results presented in Table 1 clearly indicate that the thermal behaviour of the examined bio composite materials is affected by the cellulose content and its degradation in each of the fillers used, which is especially pronounced in case of cold crystallinity values. However, changes in glass transition temperatures are not only under the influence of fillers cellulose content, they are dependent on fillers dispersion which causes changes in free volume and polymer chain radius of gyration. Presence of filler particles also changed the values of other examined thermal values which can be attributed to changes in Gibbs free energy and fillers capability to influence the nucleation process.

cellulose acetate ; bio composites ; filler ; thermal behaviour ; wood

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