Thermal properties of polyurethane-based composites modified with chitosan for biomedical applications

Abstract

The thermal properties of chitosan and hydroxyapatite (HAp)-crosslinked polyurethanes (PU) prepared in a two-step bulk polymerization were investigated. Synthesis of PU was carried out using 1,6-hexamethylene diisocyanate, poly(ethylene glycol) 2000 and dibutyltin dilaurate as a catalyst. Various molar ratios of chitosan and 1,4-butanediol were applied, and the effects of incorporating different HAp amounts and the chitosan-to-BDO ratio were studied. It was found that the thermal properties of PU materials depend on polysaccharides and bioceramics load, which was confirmed by differential scanning calorimetry and thermogravimetry. The glass transition temperature increases with increasing chitosan fraction. Similarly, the onset temperature of degradation increased with chitosan addition. On the other hand, the presence of ceramics did not show a significant impact on the thermal properties of PU composites. Successful polymerization and chain extension of the isocyanate groups with hydroxyl moieties from chitosan and HAp were confirmed by Fourier transform infrared spectroscopy, and the morphology was examined using scanning electron microscopy.

Characterization of Highly Filled Glass Fiber/Carbon Fiber Polyurethane Composites with the Addition of Bio-Polyol Obtained through Biomass Liquefaction

“…The maximal temperature of the second step is between T maxII = 320–330 °C and arises from the degradation of hard segments of polyurethane. During this step, the break of urethane bonds occurs and a number of products such as isocyanates, polyols, amines (primary and secondary), and carbon dioxide are generated [ 30 , 31 ].…”

“…A broad peak from around 3300 to 3400 cm −1 comes from OH stretching vibrations. Peaks around 2900 and 2800 cm −1 are from aliphatic CH 2 symmetric and asymmetric stretching vibrations, respectively [ 30 ]. Stretching vibrations of carbonyl groups from urethane bond or carbonyl compounds from cellulose decomposition during the liquefaction process are present at around 1700 cm −1 [ 31 ].…”

“…From the received spectra, it can be concluded that the final product contained a significant amount of isocyanate groups, which is confirmed by the sharp and strong peak of the stretching vibrations of the isocyanate group at around 2250 cm −1 . It can be related to the presence of NCO groups at the chain ends or with the presence of unreacted isocyanate [ 30 ]. However, the difference between glass and carbon fiber filled composites can be observed in this peak intensity.…”

Synthesis and characterization of biopolyols through biomass liquefaction of wood shavings and their application in the preparation of polyurethane wood composites

“…The third stage of decomposition ranging from 383 to 406 °C (T max3 ) is due to the decomposition of the polyurethane soft segments. This decomposition may be connected to the degradation of soft segments formed by the biopolyol such as poly (ethylene glycol) segments or linkages in glycerol derivates in the polyurethane soft segments (Kosmela et al 2020;Szlachta et al 2021). Once more, the degradation temperature is significantly higher for the PPG materials (400 °C) in comparison to the PG (380 °C).…”

Synthesis of self‐healing supramolecular waterborne polyurethane with quadruple hydrogen bonds via ureidotriazine

“…As shown in Figure 6a, we used the thermogravimetric analyzer (TGA) to investigate thermal stability of SWPU-T x films. It is obvious shows in the DTG curves of SWPU-T x films (Figure S2), there are exist three weight loss stages in the thermal decomposition of the SWPU-Tx films, which are 260$315, 315$395, and 395$450 C. 46,47 With the increase of DAUTA content, the onset decomposition temperature (the temperature at 5% weight loss, T 5 ) decreased slightly. That may be attributed to the increment of molecular segments mobility by the break of quadruple hydrogen bonds at high temperatures, which will accelerate the heat diffusion in the polyurethane film.…”