Solid-State Drawing of Commercial Poly(Lactic Acid) (PLA) Based Filaments

Walker, Julian; Melaj, Mariana A.; Gimenez, Rocio Aldana; Pérez, Claudio Javier; Bernal, Celina Raquel

doi:10.3389/fmats.2019.00280

Cited by 16 publications

(11 citation statements)

References 27 publications

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“…The lowest draw ratio and the lowest temperature lead to the highest value for the elastic modulus, which could be attributed to the competition between the orientation of the macromolecular chains subjected to stretching and the relaxation of the same chains during stretching, which is hindered at a lower temperature [ 42 ]. Similar results were found by Walker et al for commercial PLA-based extruded filaments [ 43 ]. At the highest draw ratio, the decrease in stiffness, but also in the strain at break, could be associated with void generation due to overdrawing, but a deeper microstructural analysis is required to fully explain these findings [ 44 ].…”

Section: Discussionsupporting

confidence: 91%

Statistical Modeling and Optimization of the Drawing Process of Bioderived Polylactide/Poly(dodecylene furanoate) Wet-Spun Fibers

et al. 2022

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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 break (εB) of biobased wet-spun fibers constituted by neat polylactic acid (PLA) and a PLA/poly(dodecamethylene 2,5-furandicarboxylate) (PDoF) (80/20 wt/wt) blend. Drawing experiments were conducted with a design of experiment (DOE) approach following a 24 full factorial design. The results of the quasi-static tensile tests on the drawn fibers, analyzed by the analysis of variance (ANOVA) and modeled through the response surface methodology (RSM), highlight that the presence of PDoF significantly lowers E, which instead is maximized if the temperature and draw ratio are both low. On the other hand, εB is enhanced when the drawing is performed at a high temperature. Finally, a genetic algorithm was implemented to find the optimal combination of drawing parameters that maximize both E and εB. The resulting Pareto curve highlights that the temperature influences the mechanical results only for neat PLA fibers, as the stiffness increases by drawing at lower temperatures, while optimal Pareto points for PLA/PDoF fibers are mainly determined by the draw ratio and the draw rate.

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Section: Discussionsupporting

confidence: 91%

Statistical Modeling and Optimization of the Drawing Process of Bioderived Polylactide/Poly(dodecylene furanoate) Wet-Spun Fibers

et al. 2022

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“…Furthermore, the Xc of the PFs and melt-electrospun fibers were very low (17.93% and 8.72%, respectively), whereas the Xc after fiber drawing was 58.83%. The absence of a glass transition in DSC thermograms often occurs when the crystalline fraction is more abundant than the amorphous fraction, and the Tcc value is absent because the DF is fully drawn, in agreement with previous studies [49]. The melt-electrospun fibers are, therefore, more similar to a PF than a DF.…”

Section: Physical Properties Of Pla Fibers Under Different Processingsupporting

confidence: 90%

Biobased Dyes as Conductive Additives to Reduce the Diameter of Polylactic Acid Fibers during Melt Electrospinning

et al. 2020

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Electrospinning is widely used for the manufacture of fibers in the low-micrometer to nanometer range, allowing the fabrication of flexible materials with a high surface area. A distinction is made between solution and melt electrospinning. The former produces thinner fibers but requires hazardous solvents; whereas the latter is more environmentally sustainable because solvents are not required. However, the viscous melt requires high process temperatures and its low conductivity leads to thicker fibers. Here, we describe the first use of the biobased dyes alizarin; hematoxylin and quercetin as conductive additives to reduce the diameter of polylactic acid (PLA) fibers produced by melt electrospinning; combined with a biobased plasticizer to reduce the melt viscosity. The formation of a Taylor cone followed by continuous fiber deposition was observed for all PLA compounds; reducing the fiber diameter by up to 77% compared to pure PLA. The smallest average fiber diameter of 16.04 µm was achieved by adding 2% (w/w) hematoxylin. Comparative analysis revealed that the melt-electrospun fibers had a low degree of crystallinity compared to drawn filament controls—resembling partially oriented filaments. Our results form the basis of an economical and environmentally friendly process that could ultimately, provide an alternative to industrial solution electrospinning

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“…Numerous processing methods have been developed to improve the strength of the polymers. Many studies have demonstrated that solid-state drawing (SSD) can induce self-reinforcement through the maximization of macromolecular chain orientation in polymeric materials [ 80 , 81 , 82 ]. Im et al (2016, 2017) determined that the tensile strengths of PLLA monofilaments and films could be increased up to two- and nine-fold, respectively, by increasing the draw ratio using a directly designed processing machine for the SSD method ( Figure 17 a) [ 83 , 84 ].…”

Section: Biomedical Applicationsmentioning

confidence: 99%

Stereocomplex Polylactide for Drug Delivery and Biomedical Applications: A Review

Park

et al. 2021

Molecules

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Polylactide (PLA) is among the most common biodegradable polymers, with applications in various fields, such as renewable and biomedical industries. PLA features poly(D-lactic acid) (PDLA) and poly(L-lactic acid) (PLLA) enantiomers, which form stereocomplex crystals through racemic blending. PLA emerged as a promising material owing to its sustainable, eco-friendly, and fully biodegradable properties. Nevertheless, PLA still has a low applicability for drug delivery as a carrier and scaffold. Stereocomplex PLA (sc-PLA) exhibits substantially improved mechanical and physical strength compared to the homopolymer, overcoming these limitations. Recently, numerous studies have reported the use of sc-PLA as a drug carrier through encapsulation of various drugs, proteins, and secondary molecules by various processes including micelle formation, self-assembly, emulsion, and inkjet printing. However, concerns such as low loading capacity, weak stability of hydrophilic contents, and non-sustainable release behavior remain. This review focuses on various strategies to overcome the current challenges of sc-PLA in drug delivery systems and biomedical applications in three critical fields, namely anti-cancer therapy, tissue engineering, and anti-microbial activity. Furthermore, the excellent potential of sc-PLA as a next-generation polymeric material is discussed.

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Solid-State Drawing of Commercial Poly(Lactic Acid) (PLA) Based Filaments

Cited by 16 publications

References 27 publications

Statistical Modeling and Optimization of the Drawing Process of Bioderived Polylactide/Poly(dodecylene furanoate) Wet-Spun Fibers

Statistical Modeling and Optimization of the Drawing Process of Bioderived Polylactide/Poly(dodecylene furanoate) Wet-Spun Fibers

Biobased Dyes as Conductive Additives to Reduce the Diameter of Polylactic Acid Fibers during Melt Electrospinning

Stereocomplex Polylactide for Drug Delivery and Biomedical Applications: A Review

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