Effect of Aliphatic and Aromatic Chain Extenders on Thermal Stability of Graphene Oxide/Polyurethane Hybrid Composites Prepared by Sol‐Gel Method

Abstract

Hybrid composites of graphene and polyurethane (PU) were prepared via sol-gel method. The isocyanate-terminated PUs with chain extenders of pyromellitic dianhydride (PMDA) and butanediol were reacted with (3-aminopropyl) triethoxysilane (APTES) to obtain Polyurethane with PMDA chain extender (PUI) and Polyurethane with BD chain extender (PUBD), respectively. Sol-gel reaction between the silane-modified polyurethanes with APTES-modified graphene oxide resulted in the hybrid composites with high thermal degradation temperature and char content. Results of Fourier-transform infrared spectroscopy and proton nuclear magnetic resonance analysis confirmed chemical modification of graphene and successful preparation of the bifunctional silane-modified PUI and PUBD, respectively. Based on the thermogravimetric analysis (TGA) results, PMDA chain extender resulted in higher degradation temperature and char content in the hybrid composites. In addition, siloxane networks formed by sol-gel process resulted in synergistic effects on improving thermal stability of the PU materials. X-ray diffraction results in addition to the scanning and transmission electron microscopy images confirmed successful oxidation of graphite and also its modification process.

Tuning polylactic acid scaffolds for tissue engineering purposes by incorporating graphene oxide‐chitosan nano‐hybrids

“…Nonetheless, the slow rate of crystal formation and lack of sufficient surface hydrophilicity have limited its widespread bio‐applications 16‐18 . In the past decades, diverse techniques have been developed to promote the performance of polymers 19‐24 . Literature survey reveals that incorporating nanoparticles into polymers is one of the most effective methods to address these concerns 13,22,25‐27 …”

High-damping polyurethane-based composites modified with amino-functionalized graphene

“…At temperatures between 250 and 350°C, the hard segment in PU began decomposing into a diimide, an olefin, and carbon dioxide. 40,41 PBMA began disintegrating with a further increase in temperature, with the decomposition rate being the highest at ∼350°C. A second decomposition peak, which was generated by the conversion of polyurethane diimide into isocyanate, appeared at ∼400°C.…”

A review on microphase separation measurement techniques for polyurethanes

“…Controlling the phase separation can strongly influence PU properties. 6 Molecular weight and polarity of the polyol, [7][8][9] chemistry and structure of the isocyanate and chain extender, [10][11][12][13][14] isocyanate, polyol and chain extender ratios, [15][16][17] utilization of additives in polymerization process, 18 functionalization of the polymer chains [19][20][21][22] and application of shear field and the thermal process [23][24][25] can potentially affect the phase separation and accordingly the PU properties.…”