Here,
solution-cast blends of polylactic acid (PLA) and a novel
bioderived poly(pentamethylene 2,5-furanoate) (PPeF) in variable concentrations
(1–50 wt %) are prepared and investigated. The characterization
of the thin films (thickness 50 μm) highlights that PPeF strongly
improves the UV-shielding properties of PLA, with a decrease in transmittance
at 275 nm from 47.3% of neat PLA to 0.77% with only 1 wt % of PPeF,
while the transmittance decrease in the visible region at these PPeF
fractions is marginal, allowing the production of optically transparent
films. Despite the complete immiscibility of PLA/PPeF blends, PPeF
effectively enhances the ductility of PLA as the tensile strain at
break increases from 7% of neat PLA to 200% of the blend with 30 wt
% of PPeF. This composition is the most promising also from the gas-barrier
point of view as the gas transmission rates of CO2 and
O2 drop to one-fourth of those of neat PLA, comparable
to those of poly(ethylene terephthalate). These results highlight
that PLA/PPeF blends with PPeF fractions of 30 wt % are very promising
for food packaging applications, and their properties could be further
enhanced by applying suitable compatibilizers.
This work aims at producing and investigating, for the first time, the microstructural and thermo-mechanical properties of fibers constituted by poly(lactic acid) (PLA)/poly(alkylene furanoate)s (PAFs) blends for textile applications. Two different PAFs have been investigated, i.e., poly(octylene furanoate) (P8F) and poly(dodecylene furanoate) (P12F), which have been blended with PLA in different concentrations and spun through a lab-made wet spinning device. The microstructural investigation of the fiber cross-section evidenced domains of PAFs homogeneously dispersed within the PLA matrix. The immiscibility of the produced blends was also suggested by the fact that the glass transition temperature of PLA was unaffected by the presence of PAF. The thermal stability of PLA was not substantially influenced by the PAF content, whereas the water absorption tendency decreased with an increase in P12F fraction. The mechanical properties of PLA/P8F blends decreased with the P8F amount, while for PLA/P12F fiber blends the stiffness and the strength were approximatively constant by increasing the P12F content. The drawing process, performed at 70 °C and with two different draw ratios, brought an interesting increase in the mechanical properties of PLA fibers upon P12F introduction. These promising results constitute the basis for future research on these innovative bio-based fibers.
Furanoate polyesters are emerging as promising bioderived polymers that could replace petrochemical‐derived polyesters in several applications, for example, the textile field. Here, sustainable and fully bioderived fibers are wet‐spun by blending poly(lactic acid) (PLA) and poly(pentamethylene 2,5‐furanoate) (PPeF), with up to 50 wt% of PPeF. PLA/PPeF blends result as immiscible, with PPeF domains homogeneously distributed within the PLA matrix, as shown by scanning electron micrographs. The immiscibility is confirmed by differential scanning calorimetry, as the glass transition temperature of PLA is unaffected by PPeF. The immiscibility and poor adhesion between PLA and PPeF are responsible for the decrease in stress at break and elongation at break from 30.1 MPa and 127%, of PLA fibers, to 3.5 MPa and 1.9%, at high PPeF amounts. However, the addition of PPeF strongly decreases the PLA's tendency to absorb water and retain the processing solvents, showing a mass loss decrease from 3.1% for PLA fibers to 1% for fibers containing 50 wt% PPeF, thereby addressing one of the main drawbacks of PLA. These results, although preliminary, offer new directions for future works on innovative and sustainable fibers based on furanoate polyesters.
According to the European Bioplastics association, in 2017, the so-called bioplastics represented only 2.06 million tons of the 320 million tons of plastics produced annually [1]. The global production capacity is expected to increase up to 2.62 million tons in 2023. This growth is pushed by the demand of more sophisticated biopolymers, new applications and products. From packaging, agriculture, consumer electronics, textile to automotive, bioplastics are used in an increasing number of applications. In fact, biopolymers offer a number of additional advantages if compared to conventional plastics, such as a reduced carbon footprint and additional waste management options. Among bio-based and biodegradable plastics, polylactic acid (PLA) is one of the most interesting ones due to their good mechanical properties, good workability, excellent barrier properties. Therefore, it is a good candidate for the replacement of polystyrene (PS), polypropylene (PP), and acrylonitrile butadiene styrene (ABS) in many applications. However, PLA presents some weak points mainly represented by its low ductility, poor toughness, low glass transition temperature, high sensitivity to moisture and relatively low gas barrier, that limit its use in packaging applications [2, 3]. Indeed, the main
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