The effect of radiation on the thermal properties of chitosan/mimosa tenuiflora and chitosan/mimosa tenuiflora/multiwalled carbon nanotubes (MWCNT) composites for bone tissue engineering

Abstract

The purpose of this study is to examine the effect of gamma radiation and UV radiation on the microstructure, chemical structure and thermal stability of Chitosan/Mimosa Tenuiflora and Chitosan/Mimosa Tenuiflora/MWCNT composites scaffolds produced by thermally induced phase separation. The composites were irradiated and observed to undergo radiation-induced degradation through chain scission. Morphology, thermal properties and effects on chemical and semi-crystalline structures were obtained by scanning electronic microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), FT-IR analysis and X-ray Diffraction. A relationship between radiation type and the thermal stability of the composites, were also established. This relationship allows a more accurate and precise control of the life span of Chitosan/Mimosa Tenuiflora and Chitosan/Mimosa Tenuiflora/MWCNT composites through the use of radiation in materials for use in tissue engineering.

Structural, Thermal and Optical Modifications of Chitosan due to UV-Ozone Irradiation

“…However, no variations in the values of the peak temperatures were detected between the unexposed and exposed chitosan up to 38.75 x 10 -14 J/m 2 . This is in consistent with that previously reported [17,23]. Table 3b presented that, at the end of the thermal decompositions, the total % weight loss decreased by exposure to UV-ozone for 9.68 x 10 -14 and 19.35 x 10 -14 J/m 2 and then increased by increasing the exposure dose up to 38.75 x 10 -14 J/ m 2 but was lower than that of the unexposed value.…”

“…The crystallinity of chitosan was produced by a large number of amino and hydroxyl groups present in its structure [21]. The obtained result was in agreement with that previously reported by many investigators [10,17,22,23]. Also, the crystallinity of the chitosan powder was improved after UV-ozone radiation in comparison with the unexposed type.…”

“…Table 3 represents the variations of the % weight loss and the transition temperatures (Table 3a) as well as the total % weight loss, the total residue and its percentage change (Table 3b) before and after exposure of chitosan powder for the two decomposition regions. Figure 5 and Table 3a elucidated that, the first decomposition stage starting at about 25 o C was followed by thermal stability up to about 210 o C. It shows low values of % weight loss varies from about 11% for unexposed to about 7% for the exposed samples due to the moisture evaporation and depends on the initial moisture content of the powder [17,23]. When chitosan powder was heated above 60 o C, a rapid chain elimination of water has begun.…”

“…Degradation phenomenon is an unwanted phenomenon and may arise after exposure to ozone which was controlled by adjusting the exposure time. The effects of different kinds of radiation on chitosan have been studied by many investigators [16,17]. UV-ozone irradiation may induce depolymerization of chitosan.…”

Characterization of pH-responsive high molecular-weight chitosan/poly (vinyl alcohol) hydrogel prepared by gamma irradiation for localizing drug release

“…Thermal and oxidative degradations of CS were responsible for the subsequent 49% weight loss between 280 and 350 °C. It was caused by the breakdown of the primary components of CS, most notably the heat degradation of the pyranose ring and the fracture of the b-glycosidic bonds connecting the glucosamine and N-acetylglucosamine moieties (Pawlak and Mucha 2003;Martel-Estrada et al 2014). Moreover, the main decomposition (DTG curve) occurred between 300 and 414 °C Scheme 1 Proposed crosslinking process of CS/PVA hydrogel under gamma irradiation and was attributed to the dehydroxylation of PVA, suggesting the initiation of polymeric chain decomposition, and the subsequent decomposition occurred between 414 and 475 °C.…”