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Drawing is a well-established method to improve the mechanical properties of wet-spun fibers, as it orients the polymer chains, increases the chain density, and homogenizes the microstructure. This work aims to investigate how drawing variables, such as the draw ratio, drawing speed, and temperature affect the elastic modulus (E) and the strain at...
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... investigate how these variables influence the values of E and εB of the fibers, a 2 4 full factorial design [31] was used, whose factors and levels are given in Table 2. Each factor varies between two levels, normalized between −1 and +1. ...Similar publications
This study provides insight into the accelerated hydrolysis of polyester PLA through the addition of phosphites based on pentaerythritol. To control hydrolysis and ensure processing stability, different types of phosphites and combinations of phosphites with acid scavengers were studied. Therefore, commercially available PLA was compounded with sel...
Polymer-matrix composites are widely used in engineering applications. Yet, environmental factors impact their macroscale fatigue and creep performances significantly, owing to several mechanisms acting at the microstructure level. Herein, we analyse the effects of water uptake that are responsible for swelling and, over time and in enough quantity...
Poly(lactic acid) (PLA) is a polyester attracting growing interest every year in different application fields, such as packaging, cosmetics, food, medicine, etc. Despite its significant advantages, it has low elasticity that may hinder further development and a corresponding rise in volume of consumption. This review opens a discussion of basic app...
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In the modern world, plastics have become indispensable. Due to their properties, they are used for a wide variety of applications ranging from packaging materials to textiles and medical technology. The vast majority of these plastics are made from finite fossil feedstocks that will need to be replaced in the long term to meet consumer demands in...
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Polylactic acid (PLA), a highly promising biodegradable biopolymer, has been extensively studied over the last two decades. The thermoplastic polyester PLA is bio-based, compostable, and eco-friendly. Its monomer, lactic acid, is fermented from renewable plant sources like starch and sugar. Therefore, PLA is regarded as a desirable substitute for c...
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... RSM was first developed in the field of statistics by Box and Wilson in the 1950s and has since been widely applied in various fields to construct response surfaces and optimize process conditions [21]. For example, Rigotti et al. applied RSM to optimize the process parameters affecting elastic modulus and strain at break in the drawing process of bio-derived polylactide/poly(dodecylene furanoate) fibers using wet spinning [22]. Oroume et al. used RSM to optimize spinning conditions and wet spinning to improve the tensile strength of lignin/polyacrylonitrile carbon fiber precursors [23]. ...
The optimal process conditions for fabricating carbon nanotube (CNT)/polyvinylidene fluoride (PVDF) fibers with varying properties using a wet spinning process were experimentally determined. A dope solution was prepared using multi-walled nanotubes, PVDF, and dimethylacetamide, and appropriate materials were selected. Design parameters affecting the chemical and physical properties of CNT/PVDF fibers, such as bath concentration, bath temperature, drying temperature, and elongation, were determined using a response surface method. The wet-spinning conditions were analyzed based on the tensile strength and electrical conductivity of the fibers using an analysis of variance and interaction analysis. The optimized process conditions for fabricating CNT/PVDF fibers with different properties were derived and verified through fabrication using the determined design parameters.
... Our group has recently carried out a detailed investigation on PLA/PAF blends prepared via solution mixing, for the production of bioderived films [32][33][34][35][36] and fibers [37][38][39]. That work involved blending PLA not only with PBF, but also with longer-alkyl-chain PAFs such as poly(pentamethylene furanoate) (PPeF), poly(hexamethylene furanoate) (PHF), poly(octamethylene furanoate) (POF), poly(decamethylene furanoate) (PDeF), and Molecules 2023, 28, 4811 3 of 24 poly(dodecamethylene furanoate) (PDoF). ...
This work presents the successful preparation and characterization of polylactide/poly(propylene 2,5-furandicarboxylate) (PLA/PPF) and polylactide/poly(butylene 2,5-furandicarboxylate) (PLA/PBF) blends in form of bulk and fiber samples and investigates the influence of poly(alkylene furanoate) (PAF) concentration (0 to 20 wt%) and compatibilization on the physical, thermal, and mechanical properties. Both blend types, although immiscible, are successfully compatibilized by Joncryl (J), which improves the interfacial adhesion and reduces the size of PPF and PBF domains. Mechanical tests on bulk samples show that only PBF is able to effectively toughen PLA, as PLA/PBF blends with 5–10 wt% PBF showed a distinct yield point, remarkable necking propagation, and increased strain at break (up to 55%), while PPF did not show significant plasticizing effects. The toughening ability of PBF is attributed to its lower glass transition temperature and greater toughness than PPF. For fiber samples, increasing the PPF and PBF amount improves the elastic modulus and mechanical strength, particularly for PBF-containing fibers collected at higher take-up speeds. Remarkably, in fiber samples, plasticizing effects are observed for both PPF and PBF, with significantly higher strain at break values compared to neat PLA (up to 455%), likely due to a further microstructural homogenization, enhanced compatibility, and load transfer between PLA and PAF phases following the fiber spinning process. SEM analysis confirms the deformation of PPF domains, which is probably due to a “plastic–rubber” transition during tensile testing. The orientation and possible crystallization of PPF and PBF domains contribute to increased tensile strength and elastic modulus. This work showcases the potential of PPF and PBF in tailoring the thermo-mechanical properties of PLA in both bulk and fiber forms, expanding their applications in the packaging and textile industry.
... Bio-based and biodegradable polymers are polymers whose raw materials are derived from biomass and which are biodegradable. They are viable substitutes for traditional plastics because they reduce the environmental impact of plastics throughout their life cycle [4,5]. These polymers include poly(lactic acid) (PLA) [6][7][8][9][10], poly(butylene succinate) (PBS) [11,12], poly(butylene succinate-co-butylene adipate) (PBSA) [13,14], and poly(hydroxyalkanoate) (PHA) [15][16][17]. ...
In this work, the melt polycondensation method was used to synthesize aliphatic polyesters from 1,12-dodecanediol and aliphatic diacids with even carbon atoms. Gel permeation chromatography, hydrogen-1 nuclear magnetic resonance (¹H NMR), infrared spectroscopy, differential scanning calorimetry, wide-angle X-ray diffraction, thermogravimetric analysis, tensile test, dynamic mechanical analysis, and rotational rheometer were used for characterization. All polyesters had high weight average molecular weight (> 60,000 g/mol). Poly(1,12-dodecylene adipate) had the lowest weight average molecular weight (66,360 g/mol) and poor thermal stability. Four polyesters had very flexible molecular chains and shared a crystalline structure with polyethylene. Poly(1,12-dodecylene octanedioate) and poly(1,12-dodecylene sebacate) had tensile strength of 20.8 MPa and 25.3 MPa, respectively, and elongation at break of 255% and 254%, respectively, meaning that their tensile properties were similar to those of polyethylene.
... In fact, PLA has been already used in the production of sportswear, furnishings, drapes, and non−wovens, although further improvements in the moisture resistance and mechanical properties are required [31]. In previous works of our group, PAFs have already been blended with PLA to produce wet−spun fibers, which showed promising improvements in the mechanical properties, thermal stability, and water absorption tendency [22,24,32]. Those works demonstrated that PLA/PAF blends with a small fraction of PAFs (max. ...
... Neat PLA, PLA/PEF, and PLA/PDoF mixtures were dissolved in a mixture of chloroform and HFIP. The ability of chloroform to dissolve both PLA and furan−based polyesters with long alkyl chains (e.g., PDoF) was previously reported [22,24,32,34], while HFIP was necessary to provide the dissolution of PEF [36]. The wet−spinning process was used to produce neat PLA fibers, PLA/PEF, and PLA/PDoF fiber blends with PEF and PDoF concentrations equal to 2.5 wt %, 5 wt %, and 10 wt %. ...
... Thus, these temperatures enable improving the deformability of the fibers, also avoiding the melting of the PDoF constituent. The drawing procedure was carried out by following the optimized parameters reported in previous work [32], i.e., by keeping the samples at 80 °C for 10 min to stabilize the temperature and then drawing them at three different draw ratios (1, 2, and 4), corresponding to once, twice, and four times the initial fiber length, at a speed of 50 mm/min. The fibers with a draw ratio of 1 were kept at 80 °C for 15 min, allowing all prepared specimens to be subjected to the same thermal treatment. ...
This work aims to produce poly(lactic acid) (PLA)/poly(alkylene furanoate)s (PAF)s fiber blends for textile applications and evaluates their microstructural, chemical, thermal, and mechanical properties. The work focuses on two PAFs with very different alkyl chain lengths, i.e., poly(ethylene 2,5−furandicarboxylate) (PEF) and poly(dodecamethylene 2,5−furandicarboxylate) (PDoF), which were blended in solution at various concentrations (in the range 2.5–10 wt %) with PLA, wet spun, and subsequently drawn. Light optical micrographs highlight that PLA/PEF blends present large and concentrate PEF domains, whereas PLA/PDoF blends show small and homogeneously distributed PDoF domains. The blends appear to be immiscible, which is confirmed also by scanning electron microscopy (SEM), Fourier−Transform Infrared (FT−IR) spectroscopy, and differential scanning calorimetry (DSC). Thermogravimetric analysis (TGA) highlights that the addition of the PAFs improves the thermal stability of the fibers. The drawing process, which was carried out at 80 °C with a heat setting step at 95 °C and at three draw ratios, improves the mechanical properties of the fibers upon the addition of the PAFs. The results obtained in this study are promising and may serve as a basis for future investigations on these novel bio−based fiber blends, which can contribute to increase the environmental sustainability of industrial textiles.
... Figure 2a-e shows the SEM micrographs of the cryofracture surface of the samples PLA-rGO10 and PLA-PDeF10-rGOx (x = 0.25-2 phr). As already observed for other PLA/PAF blends [26,27,[38][39][40], in this case the blend is also immiscible (Figure 2a), and PDeF forms smooth spheroidal domains with a poor interfacial adhesion with PLA and an average size of 1.9 ± 0.3 µm. The addition of rGO considerably modifies the appearance of the fracture surface. ...
Polylactide (PLA) is the most widely used biopolymer, but its poor ductility and scarce gas barrier properties limit its applications in the packaging field. In this work, for the first time, the properties of PLA solvent-cast films are improved by the addition of a second biopolymer, i.e., poly(decamethylene 2,5-furandicarboxylate) (PDeF), added in a weight fraction of 10 wt%, and a carbon-based nanofiller, i.e., reduced graphene oxide (rGO), added in concentrations of 0.25–2 phr. PLA and PDeF are immiscible, as evidenced by scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy, with PDeF spheroidal domains showing poor adhesion to PLA. The addition of 0.25 phr of rGO, which preferentially segregates in the PDeF domains, makes them smaller and considerably rougher and improves the interfacial interaction. Differential scanning calorimetry (DSC) confirms the immiscibility of the two polymer phases and highlights that rGO enhances the crystallinity of both polymer phases (especially of PDeF). Thermogravimetric analysis (TGA) highlights the positive impact of rGO and PDeF on the thermal degradation resistance of PLA. Quasi-static tensile tests evidence that adding 10 wt% of PDeF and a small fraction of rGO (0.25 phr) to PLA considerably enhances the strain at break, which raises from 5.3% of neat PLA to 10.0% by adding 10 wt% of PDeF, up to 75.8% by adding also 0.25 phr of rGO, thereby highlighting the compatibilizing role of rGO on this blend. On the other hand, a further increase in rGO concentration decreases the strain at break due to agglomeration but enhances the mechanical stiffness and strength up to an rGO concentration of 1 phr. Overall, these results highlight the positive and synergistic contribution of PDeF and rGO in enhancing the thermomechanical properties of PLA, and the resulting nanocomposites are promising for packaging applications.
For fiber technology new approaches such as biomimetic materials, such as silks, are being intensively explored, providing new solutions for a variety of industries, including textiles, composites, and biomedical engineering. New approaches for spinning or these materials are needed. Despite recent advances in enhancing fiber tensile properties, achieving significant improvement in tensile properties remains a tedious and challenging task, suffering from little to no controlled extrusion process and difficult optimization in high dimensional parameter spaces. Here, we show a novel robotic biomimetic pulling method that can rapidly enhance fiber tensile properties surpassing current methods in both speed and resulting fiber properties. Using a controlled fiber-pulling device with in-situ tensile measurements and adaptive optimization based on Bayesian Optimization, we can reach fiber strength exceeding 300% of the traditional full factorial design method within just a few experimental iterations. Our rapid experimental method presents a potential avenue for enhancing the performance of artificial fibers across diverse industries and applications.
The significant growth of the global population, as well as the increase in energy demand and the limitations of energy generation from fossil fuels, have become a serious challenge over the world. To address these challenges, renewable energies like biofuels are recently found as a proper alternative to conventional fuels. Although biofuel production by using various techniques such as hydrothermal liquefaction (HTL) is considered one of the most promising methods to provide energy, the challenges correlated to its progression and development are still striking. In this investigation, the HTL method was employed to produce biofuel from municipal solid waste (MSW). In this regard, the effect of various parameters such as temperature, reaction time and waste-to-water ratio on mass and energy yield were assessed. It should be stressed that the optimization of biofuel production has been accomplished by the Box-Behnken method using Design Expert 8 software. Based on the results, biofuel production has an upward trend by increasing temperature to 364.57 °C and reaction time to 88.23 min Whereas, there is an inverse relationship between the biofuel waste-to-waterater ratio, in both the context of mass and energy yield.
Despite the advantages of polylactide (PLA), its inadequate UV-shielding and gas-barrier properties undermine its wide application as a flexible packaging film for perishable items. These issues are addressed in this work by investigating the properties of melt-mixed, fully bioderived blends of polylactide (PLA) and poly(ethylene furanoate) (PEF), as a function of the PEF weight fraction (1–30 wt %) and the amount of the commercial compatibilizer/chain extender Joncryl ADR 4468 (J, 0.25–1 phr). J mitigates the immiscibility of the two polymer phases by decreasing and homogenizing the PEF domain size; for the blend containing 10 wt % of PEF, the PEF domain size drops from 0.67 ± 0.46 µm of the uncompatibilized blend to 0.26 ± 0.14 with 1 phr of J. Moreover, the increase in the complex viscosity of PLA and PLA/PEF blends with the J content evidences the effectiveness of J as a chain extender. This dual positive contribution of J is reflected in the mechanical properties of PLA/PEF blends. Whereas the uncompatibilized blend with 10 wt % of PEF shows lower mechanical performance than neat PLA, all the compatibilized blends show higher tensile strength and strain at break, while retaining their high elastic moduli. The effects of PEF on the UV- and oxygen-barrier properties of PLA are also remarkable. Adding only 1 wt % of PEF makes the blend an excellent barrier for UV rays, with the transmittance at 320 nm dropping from 52.8% of neat PLA to 0.4% of the sample with 1 wt % PEF, while keeping good transparency in the visible region. PEF is also responsible for a sensible decrease in the oxygen transmission rate, which decreases from 189 cc/m2·day for neat PLA to 144 cc/m2·day with only 1 wt % of PEF. This work emphasizes the synergistic effects of PEF and J in enhancing the thermal, mechanical, UV-shielding, and gas-barrier properties of PLA, which results in bioderived blends that are very promising for packaging applications.
Poly(ethylene 2,5-furandicarboxylate) (PEF) is an attractive biobased alternative to petroleum-based polymers. In this work, novel PEF-based nonwovens were obtained by the solution electrospinning, using as solvents: trifluoroacetic acid, its mixtures with dichloromethane and dichloroethane, and also 1,1,1,3,3,3-hexafluoro-2-propanol. The effect of solvent type and PEF concentration on fiber thickness and properties of the nonwovens was studied. The average thickness of nonwoven fibers ranged from 180 nm to 2.3 μm. The fibers were amorphous with the glass transition temperature of 85–87 °C. The nonwovens were strongly hydrophobic, with water contact angles of 144–146° although they exhibited the rose petal effect. The mechanical properties of the materials were influenced by their porosity and fiber thickness. The nonwoven electrospun from 20 wt.% PEF solution in trifluoroacetic acid, with an average fiber diameter of 2.13 μm and porosity of 74%, exhibited the highest tensile strength and elongation at break, 10.8 MPa, and 190%, respectively.
