Effect of Babassu Natural Filler on PBAT/PHB Biodegradable Blends: An Investigation of Thermal, Mechanical, and Morphological Behavior

Abstract

Blending of biodegradable polymers in combination with low-price organic fillers has proven to be a suitable approach to produce cost-effective composites in order to address pollution issues and develop products with superior mechanical properties. In the present research work PBAT/PHB/Babassu composites with 25, 50, and 75% of each polymer and 20% of Babassu were produced by melting extrusion. Their thermal, mechanical, and morphological behavior was investigated by differential scanning calorimetry (DSC), tensile testing, and scanning electron microscopy (SEM). Blending PBAT with PHB inhibited the crystallization of both polymers whereas adding Babassu did not significantly change their melting behaviour. Incorporation of Babassu reduced the tensile strength of its respective blends between 4.8 and 32.3%, and elongation at break between 26.0 and 66.3%. PBAT as highly ductile and low crystalline polymer may be seen as a crystallization tool control for PHB as well as a plasticizer to PBAT/PHB blends and PBAT/PHB/Babassu composites. As PBAT content increases: (i) elongation at break increases and (ii) surface fracture becomes more refined indicating the presence of more energy dissipation mechanisms. As PBAT/PHB/Babassu composites are biodegradable, environmental friendly, and cost effective, products based on these compounds have a great potential since their mechanical properties such as ductility, stiffness, and tensile strength are still suitable for several applications even at lower temperatures (−40 °C).

Characterization of poly-hydroxybutyrate/luffa fibers composite material

“…Reduction in tensile strength due to fiber addition was also described in PHB composites with jute and hemp fibers (Gunning et al 2013); crude lignin-rich residues (Angelini et al 2014); PBAT/babassu fibers (Beber et al 2018); and almond shell, rice husk, and seagrass (Sánchez-Safont et al 2018). As reported by Beber et al (2018) and Sánchez-Safont et al (2018) elongation at break dropped when incorporating fibers in all composites analyzed.…”

“…Reduction in tensile strength due to fiber addition was also described in PHB composites with jute and hemp fibers (Gunning et al 2013); crude lignin-rich residues (Angelini et al 2014); PBAT/babassu fibers (Beber et al 2018); and almond shell, rice husk, and seagrass (Sánchez-Safont et al 2018). As reported by Beber et al (2018) and Sánchez-Safont et al (2018) elongation at break dropped when incorporating fibers in all composites analyzed. Furthermore, Sánchez-Safont et al (2018) found a more severe decrease in tensile strength and elongation at break with increasing fiber content, while Young's modulus presented a slight increase also dependent on fiber content.…”

“…5. Poor fiber-matrix adhesion was observed in untreated fiber composites, along with the presence of voids and gaps, indicating low compatibility between the fiber and matrix (Beber et al 2018). Mercerized fibers were better embedded in the matrix (Fig.…”

The Use of Thermal Techniques in the Characterization of Bio-Sourced Polymers

“…Polyhydroxybutyrate (PHB) and poly(butyleneadipate-co-terephatalate) (PBAT) were melted extruded with 20% of Babassu, an indigenous tree of some regions of Brazil. By using DSC technique, they observed the crystallization inhibition, whilst the use of Babassu, which did not affect the melting behaviour, allowed the tuning of crystallization and the plasticization [ 13 ]. They demonstrated the key role of DSC measurements in keeping the solid state at higher temperatures for designing products able to work at high temperatures.…”

Studies on Chemical IR Images of Poly(hydroxybutyrate–co–hydroxyhexanoate)/Poly(ethylene glycol) Blends and Two-Dimensional Correlation Spectroscopy

“…To improve the properties of PHB, many attempts have been studied by copolymerization [2,8,9,10,11,12] and blending [13,14,15] with the other polymers. The PHB-based copolymers have been extensively studied using infrared (IR) [16,17,18,19] and Raman [8,10,20] spectroscopies, wide-angle X-ray scattering (WAXS) [11,20,21], X-ray diffraction (XRD) [22,23], differential scanning calorimetry (DSC) [24,25], and so on.…”