Effect of carbon nanotubes on the biodegradability of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) nanocomposites

Abstract

In this work, the effect of carbon nanotubes (CNT) on the biodegradability of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) nanocomposites with 1 and 2% (w/w) of CNT has been evaluated by biodegradation assays in aqueous medium containing microorganisms extracted from garden soil. After biodegradation process, samples of PHBV and PHBV/CNT were compared regarding magnitude of degradation by visual macroscopic analysis, by measurement of percentage of weight loss and by scanning electron microscopy (SEM). The samples were further characterized regarding roughness and hydrophilicity by contact angle measurement. The final residue resultant from biodegradation of PHBV/CNT was analyzed in a FEI Inspect F50 field emission scanning electron microscope (FESEM) in order to verify the presence of CNT. Our results indicated that CNT did not compromise the biodegradability of PHBV matrix although the biodegradation rate has decreased with the increase of CNT content as shown by the weight loss measurements. SEM analysis of PHBV/CNT nanocomposites after biodegradation process showed increased amount of CNT exposed at the matrix surface suggesting the possibility of CNT recovering after the biodegradation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48020.

Non-Isothermal Crystallization Kinetics of Injection Grade PHBV and PHBV/Carbon Nanotubes Nanocomposites Using Isoconversional Method

“…When the cooling rate increases, polymer chains have little time to organize themselves. Thus, crystallization occurs at lower temperatures and results in wider crystallization peaks resulting from more considerable heterogeneity in the crystals formed [11,38]. Figure 2 shows a comparison of the DSC cooling peaks of PHBV, PHBV/CNT, PHBV/CNT-Ox, and PHBV/CNT-GB samples.…”

“…To modulate some of PHBV´s properties, carbon nanotubes (CNT) have been studied as a viable and effective nanoparticle, due to their remarkable mechanical, thermal, and electrical properties. Adding CNTs to PHBV can improve mechanical and thermal properties, besides turning the polymer matrices into a semiconductor [1,[8][9][10][11]. However, CNTs have a strong tendency to form bundles, hampering their dispersion [12].…”

Effect of glassy carbon addition and photodegradation on the biodegradation in aqueous medium of poly (3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)/glassy carbon green composites

“…The increase in the surface roughness can increase the adhesion and proliferation of microorganisms on the surfaces of PHBV/GC-S and PHBV/GC-L samples, facilitating the biodegradation of the polymeric matrix. 17,20 However, as observed in the residual weight test it was not verified a greater biodegradation of PHBV/ GC samples when compared to the neat PHBV sample (Figure 2). I may be attributed to the hydrophobicity of GC particles, which hindered the adhesion and proliferation of microorganisms and nullified the effect of the increased surface roughness on the biodegradability of PHBV/GC green composites.…”

“…14,[44][45][46] Nonetheless, the contribution of mechanical and chemical degradation factors to the overall degradation of the samples exposed to biodegradation process can be considered minimal, since the residual weight values for all samples tested in mineral solution in the C.3 and C.5 conditions were approximately 100% the initial weight, that is, the samples did not present much weight loss during these tests (Figure 2(b),(d)). Silva et al 20 analyzed the effect of the exposure of PHBV/CNT samples to mineral solution (that is, solution without microorganisms) for 10 days and also did not verify any significant weight loss 2.…”

“…Braga et al 19 verified that titanium dioxide (TiO 2 ) nanoparticles does not hinder the biodegradability of PHBV matrix in PHBV/TiO 2 nanocomposites. However, Silva et al 20 verified that carbon nanotubes (CNT) considerably decreased the PHBV biodegradation rate in PHBV/CNT nanocomposites, which may be associated with the antimicrobial activity of the carbon filler. [21][22][23][24] Nevertheless, a comprehensive study of the effect of glassy carbon (GC) particles on the PHBV biodegradation process in PHBV/GC composites is not reported in the literature.…”