Evaluation of Different Compatibilization Strategies to Improve the Performance of Injection-Molded Green Composite Pieces Made of Polylactide Reinforced with Short Flaxseed Fibers

Agüero, Ángel; Lascano, Diego; Rojas-Lema, Sandra; Martínez, Juan Ivorra; Fenollar, O.; Torres‐Giner, Sergio

doi:10.3390/polym12040821

Cited by 51 publications

(46 citation statements)

References 89 publications

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“…It features two screws with a diameter (D) of 25 mm and a length-to-diameter ratio (L/D) of 24, while the modular barrel is equipped with 4 individual heating zones coupled to a strand die. Further details of the extruder can be found elsewhere [ 36 ]. Extrusion was performed with a screw speed of 20–25 rpm to prevent material degradation due to shear-induced viscous dissipation, a feed of 1.2 kg/h, and a barrel set temperature profile of 110–120–130–140 °C from hopper to die.…”

Section: Methodsmentioning

confidence: 99%

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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Section: Methodsmentioning

confidence: 99%

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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“…(Alicante, Spain) equipped with a screw diameter of 25 mm and a length-to-diameter (L/D) ratio of 24. Further details of the equipment can be found elsewhere [52]. The rotating speed was set to 25 rpm and the temperature profile was: 165 • C (feeding hopper)-170 • C-175 • C-180 • C (extrusion die).…”

Section: Films Preparationmentioning

confidence: 99%

Tailoring the Properties of Thermo-Compressed Polylactide Films for Food Packaging Applications by Individual and Combined Additions of Lactic Acid Oligomer and Halloysite Nanotubes

et al. 2020

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In this work, films of polylactide (PLA) prepared by extrusion and thermo-compression were plasticized with oligomer of lactic acid (OLA) at contents of 5, 10, and 20 wt%. The PLA sample containing 20 wt% of OLA was also reinforced with 3, 6, and 9 parts per hundred resin (phr) of halloysite nanotubes (HNTs) to increase the mechanical strength and thermal stability of the films. Prior to melt mixing, ultrasound-assisted dispersion of the nanoclays in OLA was carried out at 100 • C to promote the HNTs dispersion in PLA and the resultant films were characterized with the aim to ascertain their potential in food packaging. It was observed that either the individual addition of OLA or combined with 3 phr of HNTs did not significantly affect the optical properties of the PLA films, whereas higher nanoclay contents reduced lightness and induced certain green and blue tonalities. The addition of 20 wt% of OLA increased ductility of the PLA film by nearly 75% and also decreased the glass transition temperature (T g ) by over 18 • C. The incorporation of 3 phr of HNTs into the OLA-containing PLA films delayed thermal degradation by 7 • C and additionally reduced the permeabilities to water and limonene vapors by approximately 8% and 47%, respectively. Interestingly, the highest barrier performance was attained for the unfilled PLA film plasticized with 10 wt% of OLA, which was attributed to a crystallinity increase and an effect of "antiplasticization". However, loadings of 6 and 9 phr of HNTs resulted in the formation of small aggregates that impaired the performance of the blend films. The here-attained results demonstrates that the properties of ternary systems of PLA/OLA/HNTs can be tuned when the plasticizer and nanofiller contents are carefully chosen and the resultant nanocomposite films can be proposed as a bio-sourced alternative for compostable packaging applications.

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“…The screw diameter is 25 cm and its length-todiameter ratio (L/D) is 24. Further details about the extruder can be found elsewhere [29]. During melt processing, the temperature profile was set as follows:…”

Section: Manufacturing Of Filmsmentioning

confidence: 99%

On the Use of Phenolic Compounds Present in Citrus Fruits and Grapes as Natural Antioxidants for Thermo-Compressed Bio-Based High-Density Polyethylene Films

et al. 2020

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This study originally explores the use of naringin (NAR), gallic acid (GA), caffeic acid (CA), and quercetin (QUER) as natural antioxidants for bio-based high-density polyethylene (bio-HDPE). These phenolic compounds are present in various citrus fruits and grapes and can remain in their leaves, peels, pulp, and seeds as by-products or wastes after juice processing. Each natural additive was first melt-mixed at 0.8 parts per hundred resin (phr) of bio-HDPE by extrusion and the resultant pellets were shaped into films by thermo-compression. Although all the phenolic compounds colored the bio-HDPE films, their contact transparency was still preserved. The chemical analyses confirmed the successful inclusion of the phenolic compounds in bio-HDPE, though their interaction with the green polyolefin matrix was low. The mechanical performance of the bio-HDPE films was nearly unaffected by the natural compounds, presenting in all cases a ductile behavior. Interestingly, the phenolic compounds successfully increased the thermo-oxidative stability of bio-HDPE, yielding GA and QUER the highest performance. In particular, using these phenolic compounds, the onset oxidation temperature (OOT) value was improved by 43 and 41.5 °C, respectively. Similarly, the oxidation induction time (OIT) value, determined in isothermal conditions at 210 °C, increased from 4.5 min to approximately 109 and 138 min. Furthermore, the onset degradation temperature in air of bio-HDPE, measured for the 5% of mass loss (T5%), was improved by up to 21 °C after the addition of NAR. Moreover, the GA- and CA-containing bio-HDPE films showed a high antioxidant activity in alcoholic solution due to their favored release capacity, which opens up novel opportunities in active food packaging. The improved antioxidant performance of these phenolic compounds was ascribed to the multiple presence of hydroxyl groups and aromatic heterocyclic rings that provide these molecules with the features to permit the delocalization and the scavenging of free radicals. Therefore, the here-tested phenolic compounds, in particular QUER, can represent a sustainable and cost-effective alternative of synthetic antioxidants in polymer and biopolymer formulations, for which safety and environmental issues have been raised over time.

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Evaluation of Different Compatibilization Strategies to Improve the Performance of Injection-Molded Green Composite Pieces Made of Polylactide Reinforced with Short Flaxseed Fibers

Cited by 51 publications

References 89 publications

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

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

Tailoring the Properties of Thermo-Compressed Polylactide Films for Food Packaging Applications by Individual and Combined Additions of Lactic Acid Oligomer and Halloysite Nanotubes

On the Use of Phenolic Compounds Present in Citrus Fruits and Grapes as Natural Antioxidants for Thermo-Compressed Bio-Based High-Density Polyethylene Films

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