Starch‐graphene oxide bionanocomposites prepared through melt mixing

Abstract

Bionanocomposites (BNCs) of waxy corn starch, glycerol, and graphene oxide (GO) or graphite oxide (GrO) were prepared by melt mixing. First, the GrO was pre-exfoliated in a water solution using ultrasound at 1 wt %. Small-angle X-ray scattering was used to determinate the interlaminar separation of GrO and transmission electron microscopy, Fourier infrared spectroscopy, and thermogravimetric analysis were used to characterized the GrO. Next, BNCs were characterized by X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and mechanical property measurements. A complete exfoliation of GrO was obtained in the waxy corn matrix. Amorphous X-ray patterns of the BNCs were observed, indicating that the exfoliated GO avoid the retrogradation of starch. According to scanning electron microscopy results, the BNCs showed an irregular texture and a good dispersion of GO, while thermoplastic starch showed a smooth morphology with a fragile structure. The BNCs exhibited higher thermal stability than thermoplastic starch. The tensile strength and the Young's modulus increased by 140% and 230% at a GO loading levels of 0.5% due to good interfacial interactions of GO and the waxy corn starch matrix.

Synergistic effect of graphene oxide nanoplatelets and cellulose nanofibers on mechanical, thermal, and barrier properties of thermoplastic starch

“…As a consequence of this compatibility, hydrogen bond interactions can be formed between GO nanoplatelets and other phases, which lead to a more efficient stress transfer from matrix to CNF and GO nanoplatelets. Hence, the tensile strength further increases by incorporation of GO nanoplatelets . Another reason for this enhancement can be the good dispersion of GO nanoplatelets inside the matrix, which was shown by the XRD patterns in previous section and also the elongation behavior that is presented in Figure .…”

“…Tensile strength and Young modulus of samples with 0.5 wt% of GO content increased by about 140% and 230%, respectively. Their results indicated that exfoliated GO avoided the retrogradation of starch . These results show that GO is highly compatible with thermoplastic starch.…”

“…These results show that GO is highly compatible with thermoplastic starch. Thus, by the addition of GO to thermoplastic starch, its properties such as mechanical, thermal (up to 200°C), and gas barrier properties will be improved significantly …”

Trends on Synthesis of Polymeric Nanocomposites Based on Green Chemistry

“…The latter has also been demonstrated for the manufacture of biocomposites with graphite oxide where the ultrasonic oscillations were used to exfoliate the GrO on the surface of the starch granules, which were further melt blended to obtain PNCs with excellent mechanical properties [57]. Table 1 enlists some operating conditions of the ultrasound processes in the three aforementioned modalities: i) NPs pre-dispersion/exfoliation, ii) NPs dispersion/exfoliation with the polymer, and iii) NPs embedding on finished products.…”

Physical and Biodegradation Properties of Graphene Derivatives/Thermoplastic Starch Composites

“…Composites of starch and graphene derivatives have been developed and presented improvements in mechanical [7,19] and thermal [19,20] properties, as well as enhancements in electrical conductivity [20,21]. Favorable interactions and exfoliation of graphene sheets in the starch matrix explain these results.…”