Improvement of the compatibility between poly(3-hydroxybutyrate) and poly(ε-caprolactone) by reactive extrusion with dicumyl peroxide

Abstract

Poly(3-hydroxybutyrate) is a biodegradable aliphatic polyester obtained through bacterial fermentation that has gained attention in the last few years; nevertheless, its industrial applications are restricted because of some drawbacks related to its high stiffness and fragility which is associated to its high crystallinity. In this work, poly(3-hydroxybutyrate) (P3HB) was melt blended with poly(ε-caprolactone) (PCL) at a constant weight ratio of 75/25 (P3HB/PCL) by reactive extrusion with different contents of dicumyl peroxide (DCP) in the 0-1 wt% range. The effects of the DCP load on mechanical, thermal and morphology of the P3HB/PCL blend were studied. Results showed a positive increase in the elongation at break and the impactabsorbed energy of 91% and 231% respectively with regard the uncompatibilized P3HB/PCL blend by the addition of 1 wt% DCP, being this a clear evidenced of the improved compatibility between these polymers. Moreover, morphology of DCP-compatibilized P3HB/PCL blend obtained by field emission electron microscopy (FESEM) and atomic force microscopy (AFM) showed a remarkable decrease in the particle size of poly(ε-caprolactone)-rich domains randomly dispersed in the poly(3-hydroxybutyrate). In addition, both FESEM and AFM also revealed improved interfacial adhesion between P3HB-and PCL-rich phases with a noticeable decrease in the gap between them. Addition of 1 wt% DCP also contributes to lowering the degree of crystallinity of PHB by 14% in the blend and other thermal properties are not highly affected by the reactive extrusion with DCP.

Effect of pine resin derivatives on the structural, thermal, and mechanical properties of Mater‐Bi type bioplastic

“…This morphology is also characteristic of ductile fractures in poor cohesion materials, mainly observed in binary or ternary blends with low miscibility [Figure (a)] . Specifically, small spheres attributed to the minor portion of PCL are observed . As well, plasticized starch domains are also observed and as a major component the PBAT portion.…”

“…Mater‐Bi exhibited a thermal transition at −32 °C, corresponding mainly to the glass transition of the PBAT fraction ( T gPBAT ) with a combination of T g of the plasticized starch fraction ( T gplasticized starch ) of the Mater‐Bi . In addition, Mater‐Bi presents a thermal transition at 56.3 °C, attributed to the PCL melting . Since the PCL content in Mater‐Bi is estimated to be less than 10 wt %, this thermal transition is very trivial, and no melting peak is observed.…”

Enhancing the Thermal Stability of Polypropylene by Blending with Low Amounts of Natural Antioxidants

“…The elastic modulus was also analyzed by the quantitative nanomechanical method using an AFM‐QNM. This technique allows to perform a map of elastic modulus on the surface of samples by indenting very small volumes of material at very low depths of 2–5 nm . In this study, we propose and explore the possibility to use this technique to reveal a possible lack of miscibility between the PP matrix and the additives by studding the homogeneity of the properties reached.…”

“…Furthermore, the very superficially elastic modulus of the surface of several samples was analyzed by atomic force microscope (Veeco Nanoscope) working at peak‐force mode. By forcing the tip at a maximum constant 5 nm depth, the force curves were recorded and subsequently fitted by the DMT model, obtaining elastic maps of the analyzed square 10 × 10 µm areas.…”

From Obtaining to Degradation of PHB:Material Properties. Part I

“…According Garcia-Garcia et al [90], the compatibility of a blend PHB with PCL was improved by reactive extrusion with different DCP contents, led to a remarkable increase in ductile properties such as elongation at break and impact-absorbed energy. Addition of 1 wt % DCP also contributes to lowering the degree of cristallinity of PHB.…”