The effect of maleinized linseed oil as biobased plasticizer in poly (lactic acid)-based formulations

[EN] The use of maleinized linseed oil (MLO) as a potential biobased plasticizer for poly(lactic acid) (PLA) industrial formulations with improved toughness was evaluated. MLO content varied in the range 0-20 phr (parts by weight of MLO per hundred parts by weight of PLA). Mechanical, thermal and morphological characterizations were used to assess the potential of MLO as an environmentally friendly plasticizer for PLA formulations. Dynamic mechanical thermal analysis and differential scanning calorimetry revealed anoticeable decrease in the glass transition temperature of about 6.5 degrees C compared to neat PLA. In addition, the cold crystallization process was favoured with MLO content due to the increased chain mobility that the plasticizer provides. PLA toughness was markedly improved in formulations with 5 phr MLO, while maximum elongation at break was obtained for PLA formulations plasticized with MLO content in the range 15-20 phr. Scanning electron microscopy revealed evidence of plastic deformation. Nevertheless, phase separation was detected in plasticized PLA formulations with high MLO content (above 15-20 phr MLO), which had a negative effect on overall toughness. (C) 2017 Society of Chemical IndustryThis research was funded by the Ministry of Economy and Competitiveness - MINECO, ref. MAT2014-59242-C2-1-R. The authors also thank Conselleria d'Educacio, Cultura i Esport - Generalitat Valenciana, ref. GV/2014/008, for financial support. DG-G thanks the Spanish Ministry of Education, Culture and Sports for financial support through an FPU grant (FPU13/06011).Ferri, J.; Garcia-Garcia, D.; Montanes, N.; Fenollar, O.; Balart, R. (2017). The effect of maleinized linseed oil as biobased plasticizer in poly (lactic acid)-based formulations. Polymer International. 66(6):882-891. https://doi.org/10.1002/pi.5329S88289166

Enhancing Osteoconduction of PLLA-Based Nanocomposite Scaffolds for Bone Regeneration Using Different Biomimetic Signals to MSCs

In bone engineering, the adhesion, proliferation and differentiation of mesenchymal stromal cells rely on signaling from chemico-physical structure of the substrate, therefore prompting the design of mimetic “extracellular matrix”-like scaffolds. In this study, three-dimensional porous poly-L-lactic acid (PLLA)-based scaffolds have been mixed with different components, including single walled carbon nanotubes (CNT), micro-hydroxyapatite particles (HA), and BMP2, and treated with plasma (PT), to obtain four different nanocomposites: PLLA + CNT, PLLA + CNTHA, PLLA + CNT + HA + BMP2 and PLLA + CNT + HA + PT. Adult bone marrow mesenchymal stromal cells (MSCs) were derived from the femur of orthopaedic patients, seeded on the scaffolds and cultured under osteogenic induction up to differentiation and mineralization. The release of specific metabolites and temporal gene expression profiles of marrow-derived osteoprogenitors were analyzed at definite time points, relevant to in vitro culture as well as in vivo differentiation. As a result, the role of the different biomimetic components added to the PLLA matrix was deciphered, with BMP2-added scaffolds showing the highest biomimetic activity on cells differentiating to mature osteoblasts. The modification of a polymeric scaffold with reinforcing components which also work as biomimetic cues for cells can effectively direct osteoprogenitor cells differentiation, so as to shorten the time required for mineralization