Polyhydroxyalkanoates/Fibrillated Nanocellulose Composites for Additive Manufacturing

Valentini, Francesco; Dorigato, Andrea; Rigotti, Daniele; Pegoretti, Alessandro

doi:10.1007/s10924-019-01429-8

Cited by 67 publications

(44 citation statements)

References 22 publications

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“…The melting temperature, T m , is slightly higher for the composites compared to the neat polymer. These results are consistent with already published data and can be ascribed to the reduced flexibility of the PHBH chains, due to the filler presence.…”

Section: Resultssupporting

confidence: 93%

New biocomposite obtained using poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) (PHBH) and microfibrillated cellulose

Giubilini

Sciancalepore

Messori

et al. 2020

J of Applied Polymer Sci

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This research evaluates the effects of filler content and silanization on thermal, morphological and mechanical properties of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH)-based composites. Microfibrillated cellulose (MFC) was obtained by a mechanical treatment of high-pressure homogenization, starting from oat hull fiber, a byproduct of the agri-food sector. MFC reinforced PHBH composites were prepared by melt compounding. SEM and FT-IR analysis showed a good dispersion of the filler in the polymeric matrix, denoting the effectiveness of the surface silanization process. The thermal stability of PHBH composites remains substantially unchanged, and the glass transition temperature marginally increases with the increase of the filler content. Furthermore, silanized MFC shows slightly reinforcing mechanical effects on PHBH composites, such as the increase of 10% of the Young modulus with an increase of the maximum tensile stress as well. This finding has an economical interest since the results showed that MFC, deriving from a byproduct, can be successfully used as filler, decreasing the cost of the bio-based compound leaving substantially unaltered its mechanical and thermal properties.

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Section: Resultssupporting

confidence: 93%

New biocomposite obtained using poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) (PHBH) and microfibrillated cellulose

Giubilini

Sciancalepore

Messori

et al. 2020

J of Applied Polymer Sci

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“…Since the position of the tan δ peak gives an indication of the biopolymer’s T g , these values were also included in Table 7 . In the case of the neat P(3HB- co -3HHx) part, the tan δ peak was located at 10.7 °C, which is similar to that reported by Valentini et al [ 69 ]. It is worth mentioning that, in all cases, the tan δ peaks were approximately 10 °C higher than the T g values.…”

Section: Resultssupporting

confidence: 88%

Assessment of the Mechanical and Thermal Properties of Injection-Molded Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)/Hydroxyapatite Nanoparticles Parts for Use in Bone Tissue Engineering

et al. 2020

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In the present study, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)] was reinforced with hydroxyapatite nanoparticles (nHA) to produce novel nanocomposites for potential uses in bone reconstruction. Contents of nHA in the 2.5–20 wt % range were incorporated into P(3HB-co-3HHx) by melt compounding and the resulting pellets were shaped into parts by injection molding. The addition of nHA improved the mechanical strength and the thermomechanical resistance of the microbial copolyester parts. In particular, the addition of 20 wt % of nHA increased the tensile (Et) and flexural (Ef) moduli by approximately 64% and 61%, respectively. At the highest contents, however, the nanoparticles tended to agglomerate, and the ductility, toughness, and thermal stability of the parts also declined. The P(3HB-co-3HHx) parts filled with nHA contents of up to 10 wt % matched more closely the mechanical properties of the native bone in terms of strength and ductility when compared with metal alloys and other biopolymers used in bone tissue engineering. This fact, in combination with their biocompatibility, enables the development of nanocomposite parts to be applied as low-stress implantable devices that can promote bone reconstruction and be reabsorbed into the human body.

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“…FFF is a technology which allows the production of complex three-dimensional objects starting from a computer-aided design computer aided design (CAD) model. The model, in order to be recognized by the printer, is first converted into digital format and then, using a specific software, is sliced into layers [47][48][49]. Then, the model is ready for starting the printing process [50].…”

Section: Introductionmentioning

confidence: 99%

Novel Poly(Caprolactone)/Epoxy Blends by Additive Manufacturing

2020

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The aim of this work was the development of a thermoplastic/thermosetting combined system with a novel production technique. A poly(caprolactone) (PCL) structure has been designed and produced by fused filament fabrication, and impregnated with an epoxy matrix. The mechanical properties, fracture toughness, and thermal healing capacities of this blend (EP-PCL(3D)) were compared with those of a conventional melt mixed poly(caprolactone)/epoxy blend (EP-PCL). The fine dispersion of the PCL domains within the epoxy in the EP-PCL samples was responsible of a noticeable toughening effect, while in the EP-PCL(3D) structure the two phases showed an independent behavior, and fracture propagation in the epoxy was followed by the progressive yielding of the PCL domains. This peculiar behavior of EP-PCL(3D) system allowed the PCL phase to express its full potential as energy absorber under impact conditions. Optical microscope images on the fracture surfaces of the EP-PCL(3D) samples revealed that during fracture toughness tests the crack mainly propagated within the epoxy phase, while PCL contributed to energy absorption through plastic deformation. Due to the selected PCL concentration in the blends (35 vol %) and to the discrepancy between the mechanical properties of the constituents, the healing efficiency values of the two systems were rather limited.Materials 2020, 13, 819 2 of 17 processing and mixing steps are very important to obtain a good morphology and high mechanical properties. Epoxy/thermoplastic polymer blends can be produced through mechanical methods, by using batch or continuous mixers [27] or continuous polymerization reactors [28]. In the low-shear batch mixers, the thermosetting epoxy resin base is heated at high temperature to allow a better homogenization and dispersion with the thermoplastic powders, and then the curing agent is added. After degassing, the mixture can be either partially cured and then quenched or directly casted into molds for final curing. This type of mixing is not efficient for concentrations of the thermoplastic phase higher than about 30 wt %, because the viscosity of the system becomes too high to allow an efficient process. Epoxy/thermoplastic polymer blends can be also produced through non-mechanical methods, such as solvent casting, resonant acoustic mixers, and in-situ polymerization processes. Depending on the chemical nature of the constituents and on the processing route, different morphologies can be obtained for epoxy/thermoplastics blends. Homogeneous microstructures can be produced when the thermoplastic phase is soluble in the epoxy matrix and if this condition is maintained during the curing process. The homogeneity can be either due to low concentration of the thermoplastic component or due to the good affinity between the different phases. Examples of epoxy blends which remain homogeneous are those with polycarbonate and poly(ε-caprolactone) [29,30]. Heterogeneous microstructures can be obtained either with an initial immiscible mixture or starting with a homo...

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Polyhydroxyalkanoates/Fibrillated Nanocellulose Composites for Additive Manufacturing

Cited by 67 publications

References 22 publications

New biocomposite obtained using poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) (PHBH) and microfibrillated cellulose

New biocomposite obtained using poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) (PHBH) and microfibrillated cellulose

Assessment of the Mechanical and Thermal Properties of Injection-Molded Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)/Hydroxyapatite Nanoparticles Parts for Use in Bone Tissue Engineering

Novel Poly(Caprolactone)/Epoxy Blends by Additive Manufacturing

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