Poly(lactic acid) formulations with improved toughness by physical blending with thermoplastic starch

This is the peer reviewed version of the following article: Ferri, J.M., Garcia-Garcia, D., Carbonell-Verdu, A., Fenollar, Octavio, Balart, Rafael. (2018). Poly(lactic acid) formulations with improved toughness by physical blending with thermoplastic starch.Journal of Applied Polymer Science, 135, 4, 45751-. DOI: 10.1002/app.45751, which has been published in final form at http://doi.org/10.1002/app.45751. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] This work focuses on poly(lactic acid) (PLA) formulations with improved toughness by physical blending with thermoplastic maize starch (TPS) plasticized with aliphatic¿aromatic copolyester up to 30 wt %. A noticeable increase in toughness is observed, due to the finely dispersed spherical TPS domains in the PLA matrix. It is worth to note the remarkable increase in the elongation at break that changes from 7% (neat PLA) up to 21.5% for PLA with 30 wt % TPS. The impact-absorbed energy is markedly improved from the relatively low values of neat PLA (1.6 J/m2) up to more than three times. Although TPS is less thermally stable than PLA due to its plasticizer content, in general, PLA/TPS blends offer good balanced thermal stability. The morphology reveals high immiscibility in PLA/TPS blends, with TPS-rich domains with an average size of 1 micrometre, finely dispersed which, in turn, is responsible for the improved toughness.Authors thank the Ministry of Economy and Competitiveness (MINECO), Ref.: MAT2014–59242-C2-1-R for their support. Authors also thank “Conselleria d’Educacio, Cultura i Esport”- Generalitat Valenciana, Ref.: GV/2014/008 for financial support.Ferri, J.; Garcia-Garcia, D.; Carbonell-Verdu, A.; Fenollar, O.; Balart, R. (2018). Poly(lactic acid) formulations with improved toughness by physical blending with thermoplastic starch. Journal of Applied Polymer Science. 135(4). https://doi.org/10.1002/app.45751S45751135

Development and characterization of a new natural fiber reinforced thermoplastic (NFRP) with Cortaderia selloana (Pampa grass) short fibers

[EN] In this work, fully bio-based thermoplastic composites are manufactured with bio-based polyethylene (from sugarcane) and short fibers coming from Cortaderia selloana (CS) wastes. These wastes are characterized by high cellulose content, which can provide high stiffness to the polymeric matrix. The effect of Cortaderia selloana short fibers on thermal properties has been evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The effect of the filler load on mechanical properties has also been evaluated by tensile and impact tests as well as the effects of different coupling agents. Fiber-matrix interactions have been studied by scanning electron microscopy (SEM). The addition of 15-30 wt% Cortaderia selloana short fiber leads to high elastic and flexural modulus without remarkable changes in thermal degradation of the polymer composite. (C) 2017 Elsevier Ltd. All rights reserved.This work was funded by the Conselleria d'Educacio, Cultura i Esport (Generalitat Valenciana) Ref: GV/2014/008. The authors declare that they have no conflict of interest.Jorda-Vilaplana, A.; Carbonell-Verdu, A.; Samper, M.; Pop, A.; García Sanoguera, D. (2017). Development and characterization of a new natural fiber reinforced thermoplastic (NFRP) with Cortaderia selloana (Pampa grass) short fibers. Composites Science and Technology. 145:1-9. https://doi.org/10.1016/j.compscitech.2017.03.036S1914

Plasticization effect of epoxidized cottonseed oil (ECSO) on poly(lactic acid)

[EN] In this work, the use of an environmentally friendly plasticizer derived epoxidized cottonseed oil (ECSO) for poly(lactic acid) (PLA) is proposed. Melt extrusion was used to plasticize PLA formulations with different ECSO contents in the 0 - 10 wt.%. PLA formulation with 10 wt.% shows a remarkable increase in mechanical ductile properties with a percentage increase in elongation at break of more than 1100% and a noticeable increase in the impact absorbed energy. Differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) revealed a clear decrease in the glass transition temperature of neat PLA as the ECSO content increased. Field emission scanning electron microscopy (FESEM) of fractured surfaces from impact tests showed an improvement of ductility with typical rough and porous topographies. Migration tests in n-hexane at different temperatures revealed very low migration properties thus leading to new interesting plasticizers for improved PLA industrial formulations.This research was supported by the Spanish Ministry of Economy and Competitiveness - MINECO, Ref: MAT2014-59242-C2-1-R. Authors also thank to "Conselleria d'Educacio, Cultura i Esport" - Generalitat Valenciana, Ref: GV/2014/008 for financial support. A. Carbonell-Verdu wants to thank Universitat Politecnica de Valencia for financial support through an FPI grant. D. Garcia-Garcia wants to thanks the Spanish Ministry of Education, Culture and Sports for their financial support through an FPU grant (FPU13/06011).Carbonell-Verdu, A.; Samper, M.; Garcia-Garcia, D.; Sanchez-Nacher, L.; Balart, R. (2017). Plasticization effect of epoxidized cottonseed oil (ECSO) on poly(lactic acid). Industrial Crops and Products. 104:278-286. https://doi.org/10.1016/j.indcrop.2017.04.050S27828610

PLA films with improved flexibility properties by using maleinized cottonseed oil

[EN] This work assesses the potential of maleinized cottonseed oil MCSO as plasticizer in poly(lactic acid) PLA films with improved ductile behaviour. The effects of MCSO are compared with commercially available maleinized oil, i.e. maleinized linseed oil MLO in terms of mechanical, thermal and barrier properties, as well as morphology changes. Plasticized PLA formulations were obtained with a maleinized oil content in the 0 10 wt% range. Addition of both maleinized vegetable oils leads to a slight decrease in the glass transition temperature (Tg) of neat PLA from 63 °C to 60 61 °C. Nevertheless, MCSO provides better overall properties. Addition of 7.5 wt% MCSO increases the elongation at break by 292%. Regarding the barrier properties, both maleinized vegetable oils increase the oxygen transmission rate OTR. Nevertheless, this increase is less pronounced in the case of MCSO thus indicating its higher efficiency compared to MLO. On the other hand, addition of both maleinized vegetable oils do not compromise the overall disintegration of the obtained PLA formulations, thus positioning these additives as environmentally friendly solutions to increase ductile properties in PLA-based films.This research was supported by the Ministry of Economy and Competitiveness - MINECO, Ref: MAT2014-59242-C2-1-R. Carbonell-Verdu wants to thank Universitat Politecnica de Valencia for financial support through an FPI grant. Garcia-Garcia wants to thanks the Spanish Ministry of Education, Culture and Sports for their financial support through an FPU grant (FPU13/06011).Carbonell-Verdu, A.; Garcia-Garcia, D.; Dominici, F.; Torre, L.; Sanchez-Nacher, L.; Balart, R. (2017). PLA films with improved flexibility properties by using maleinized cottonseed oil. European Polymer Journal. 91:248-259. https://doi.org/10.1016/j.eurpolymj.2017.04.013S2482599

Manufacturing and compatibilization of PLA/PBAT binary blends by cottonseed oil-based derivatives

[EN] This research work aims at the compatibilization of poly(lactic acid)/poly(butylene adipate-co-terephthalate), PLA/PBAT binary blends by using cottonseed oil derivatives, i.e. epoxidized (ECSO) and maleinized (MCSO) cottonseed oil. The potential of these vegetable oil-based compatibilizers are compared versus the effects of a conventional styrene-acrylic oligomer. The base PLA/PBAT binary blend composition was 80 wt% PLA/20 wt% PBAT and the amount of compatibilizer was set to 1 and 7.5 wt%. The effects of the different compatibilizers were evaluated on PLA/PBAT films in terms of mechanical and thermal properties as well as blend's morphology by field emission scanning electron microscopy (FESEM). Complementary, biodisintegration tests in controlled compost soil and surface properties were evaluated to assess the effects of the compatibilizers. Addition of 1 wt% ECSO and MCSO led to a remarkable increase in the elongation at break up to values over 100% with regard to neat PLA. Despite this, maximum elongation at break was obtained for the compatibilized PLA/PBAT blend with 7.5 wt% MCSO, reaching values of about 321.2% respect neat PLA keeping mechanical resistant properties, such as Young's modulus and tensile strength, at high levels. Therefore, vegetable oil-derived compatibilizers stand out as environmentally friendly additives for PLA/PBAT binary blends with improved properties.This work was supported by the Ministry of Economy and Competitiveness (MINECO) (grant number MAT2017-84909-C2-2-R). A. Carbonell-Verdu wants to thank Universitat Politecnica de Valencia for financial support through an FPI grant.Carbonell-Verdu, A.; Ferri, J.; Dominici, F.; Boronat, T.; Sanchez-Nacher, L.; Balart, R.; Torre, L. (2018). Manufacturing and compatibilization of PLA/PBAT binary blends by cottonseed oil-based derivatives. eXPRESS Polymer Letters. 12(9):808-823. https://doi.org/10.3144/expresspolymlett.2018.69S80882312

Effect of different compatibilizers on injection-molded green composite pieces based on polylactide filled with almond shell flour

[EN] Green composites made of polylactide (PLA) filled with almond shell flour (ASF) at a constant weight content of 25¿wt.-% were manufactured by injection molding. In order to increase the interfacial adhesion between the biopolymer and the lignocellulosic fillers, three different compatibilizers were tested, namely multi-functional epoxy-based styrene-acrylic oligomer (ESAO), aromatic carbodiimide (AC), and maleinized linseed oil (MLO). The effect of each compatibilizer on the thermal, mechanical, and thermomechanical properties and water uptake of the injection-molded PLA/ASF pieces was analyzed. The obtained results indicated that all the here-studied compatibilizers had a positive influence on both the thermal stability and the mechanical and thermomechanical performance of the green composite pieces but low impact on their water uptake profile. In addition, the morphological analysis performed at the fracture surfaces of the green composite pieces revealed that the filler¿matrix gap was substantially reduced. Among the tested compatibilizers, ESAO and MLO yielded the highest performance in terms of mechanical strength and ductility, respectively. In the case of MLO, it also offers the advantage of being a plant-derived additive so that its application in green composites positively contributes to the development of sustainable polymer technologies.This research was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) program number MAT2014-59242-C2-1-R and AGL2015-63855-C2-1-R and Generalitat Valenciana (GV) program number GV/2014/008. A. Carbonell-Verdu wants to thank Universitat Politecnica de Valencia (UPV) for his FPI grant. D. Garcia-Garcia wants to thank the Spanish Ministry of Education, Culture and Sports (MECD) for his FPU grant (FPU13/06011). L. Quiles-Carrillo also wants to thank GV for his FPI grant (ACT/2016/182) and the MECD for his FPU grant (FPU15/03812).Quiles-Carrillo, L.; Montanes, N.; Garcia-Garcia, D.; Carbonell-Verdu, A.; Balart, R.; Torres-Giner, S. (2018). Effect of different compatibilizers on injection-molded green composite pieces based on polylactide filled with almond shell flour. Composites Part B Engineering. 147:76-85. https://doi.org/10.1016/j.compositesb.2018.04.017S768514