The effect of maleinized linseed oil (MLO) on mechanical performance of poly(lactic acid)-thermoplastic starch (PLA-TPS) blends

[EN] In this work, poly(lactic acid), PLA and thermoplastic starch, TPS blends (with a fixed content of 30 wt.% TPS) were prepared by melt extrusion process to increase the low ductile properties of PLA. The TPS used contains an aliphatic/aromatic biodegradable polyester (AAPE) that provides good resistance to aging and moisture. This blend provides slightly improved ductile properties with an increase in elongation at break of 21.5% but phase separation is observed due to the lack of strong interactions between the two polymers. Small amounts of maleinized linseed oil (MLO) can positively contribute to improve the ductile properties of these blends by a combined plasticizing-compatibilizing effect. The elongation at break increases over 160% with the only addition of 6 phr MLO. One of the evidence of the plasticizing-compatibilizing effect provided by MLO is the change in the glass transition temperature (Tg) with a decrease of about 10 °C. Field emission scanning electron microscopy (FESEM) of PLA-TPS blends with varying amounts of maleinized linseed oil also suggests an increase in compatibility.This research was supported by the 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.Ferri Azor, JM.; García García, D.; Sánchez Nacher, L.; Fenollar Gimeno, OÁ.; Balart Gimeno, RA. (2016). The effect of maleinized linseed oil (MLO) on mechanical performance of poly(lactic acid)-thermoplastic starch (PLA-TPS) blends. Carbohydrate Polymers. 147:60-68. https://doi.org/10.1016/j.carbpol.2016.03.082S606814

Solid-state modification of poly(butylene terephthalate): Design of process from calorimetric methods for catalyst investigation to reactive extrusion

The production of plastics has been increasing for more than half a century and the problem with significant growth is the waste associated with this activity. At this time, polymers are mainly recycled by classical pathway (e.g., mechanical or chemical recycling) but at the moment these techniques still present several issues (e.g., obtaining unclean material, etc.). In this study, it is proposed to reuse the materials to give them a second life by solid-state modification (SSM). This paper reports the design of a new process based on SSM technique of polyesters from batch into a continuous process. Poly(butylene terephthalate) (PBT) and 1,12-dodecanediol (DDO) are used as model compounds. At first, a calorimetric method is developed to investigate the main fea-tures of the reaction at small scale and make the proper choice of catalyst with the help of differential scanning calorimetry (DSC). At the second step, a qualitative kinetic discussion confirms our calorimetric results and the influence of the reaction time on the molecular and thermal characteristics of the copolymers obtained. The optimized conditions are then transferred to a gram-scale batch reactor and finally tested in reactive extrusion (REx) continuous process allowing to decrease the reaction time as much as possible and to test the shear forces in the SSM framework. This study therefore encompasses the design of a new process for recycling polymeric materials and offers the possibility of making polymers more sustainable

Poly(lactic acid)/carbon nanotube nanocomposites with integrated degradation sensing

International audienc

Self-nucleation and crystallization kinetics of double crystalline poly(p-dioxanone)-b-poly(epsilon-caprolactone) diblock copolymers

The crystallization kinetics of each constituent of poly(p-dioxanone)-b-poly(epsilon-caprolactone) diblock copolymers (PPDX-b-PCL) has been determined in a wide composition range by differential scanning calorimetry and compared to that of the equivalent homopolymers. Spherulitic growth rates were also measured by polarized optical microscopy while atomic force microscopy was employed to reveal the morphology of one selected diblock copolymer. It was found that crystallization drives structure formation and both components form lamellae within mixed spherulitic superstructures. The overall isothermal crystallization kinetics of the PPDX block at high temperatures, where the PCL is molten, was determined by accelerating the kinetics through a previous self-nucleation procedure. The application of the Lauritzen and Ho. man theory to overall growth rate data yielded successful results for PPDX and the diblock copolymers. The theory was applied to isothermal overall crystallization of previously self-nucleated PPDX ( where growth should be the dominant factor if self-nucleation was effective) and the energetic parameters obtained were perfectly matched with those obtained from spherulitic growth rate data of neat PPDX. A quantitative estimate of the increase in the energy barrier for crystallization of the PPDX block, caused by the covalently bonded molten PCL as compared to homo-PPDX, was thus determined. This energy increase can dramatically reduce the crystallization rate of the PPDX block as compared to homo-PPDX. In the case of the PCL block, both the crystallization kinetics and the self-nucleation results indicate that the PPDX is able to nucleate the PCL within the copolymers and heterogeneous nucleation is always present regardless of composition. Finally, preliminary results on hydrolytic degradation showed that the presence of relatively small amounts of PCL within PPDX-bPCL copolymers substantially retards hydrolytic degradation of the material in comparison to homo-PPDX. This increased resistance to hydrolysis is a complex function of composition and its knowledge may allow future prediction of the lifetime of the material for biomedical applications

Effect of the addition of polyester-grafted-cellulose nanocrystals on the shape memory properties of biodegradable PLA/PCL nanocomposites

In this work the thermally-activated shape memory response of biodegradable nanocomposites based on PLA/PCL blend reinforced with different type of cellulose nanocrystals has been reported, and compared with those of the neat matrix, at the same transition temperature of 55 °C and at the same different deformations, 50%, 100% and 150%. In particular, cellulose nanocrystals have been synthesized and then functionalized by “grafting from” reaction by ring opening polymerization of both PLLA and PCL using the –OH groups onto the cellulose nanocrystals surface as initiators for the reaction. The morphology, thermal and mechanical analysis have been performed in order to obtain the parameters for the thermo-mechanical shape memory cycles. Moreover, the addition of the CNC-based nanofillers on the compatibility of PLA-PCL blends in 70:30 proportion has been evaluated. All the biodegradable nanocomposite formulations showed excellent shape memory response, similar to those of the neat matrix, with strain recovery ratio and strain fixity ratio higher than 80% and 90%, respectively. This fact indicates that in this case, the shape memory response of the nanocomposites is mainly controlled by the response of the neat blend and they are slightly influenced by the increase of compatibility between the components of the blend. In addition, all nanocomposite films were fully disintegrated under composting conditions confirming their biodegradable nature, obtaining that the presence of CNC-based nanofillers speeds up the disintegration rate of the nanocomposites in comparison with the pure matrix.Authors thank the Spanish Ministry of Economy, Industry and Competitiveness (MINEICO) (MAT2017-88123-P), POLYMAGIC: (PCIN-2017-036) cofinanced with FEDER funds and the Regional Government of Madrid (S2013/MIT-2862). M.P.A. and L.P. acknowledge the “Juan de la Cierva” (FJCI-2014-20630) and “Ramon y Cajal” (RYC-2014-15595) contracts from the MINEICO, respectively. The authors also thank CSIC for the I-Link project (ILink1149). JMR is a FRS-FNRS research associatePeer Reviewe

Tilted fiber Bragg gratings as a new sensing device for in situ and real time monitoring of surface-initiated polymerization

The in situ and real time monitoring of surface-initiated polymerization was performed through tilted fiber Bragg gratings. The combination of gratings and stimuli responsive polymers represents a very appealing technology for the development of new sensing devices. © 2014 The Royal Society of Chemistry.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Effect of extrusion and fused filament fabrication processing parameters of recycled poly(ethylene terephthalate) on the crystallinity and mechanical properties

The production of plastic has grown exponentially over the past few decades and with it the amount of plastic waste leaking in the environment, where it fragments into micro-and nanoplastics. This problematic situation stresses the need for increased plastic collection, recycling and reuse rates. Extrusion-based additive manufacturing (AM) and especially fused filament fabrication (FFF) offer an efficient and effective method to reuse and upcycle recycled plastic. This study focuses on poly(ethylene terephthalate) (PET), which has a broad application window and its recycling is therefore environmentally and economically favorable and sustainable. Therefore, this study involves the thermal and mechanical behavior of recycled PET after extrusion and 3D printing. The extrusion parameters are optimized by performing a complete physico-chemical and thermal analysis of the obtained filaments and they were compared with commercial virgin and recycled PET. Moreover, the influence of the applied processing conditions on the degree of crystallinity and mechanical properties is investigated. The filaments are then used for FFF, where various printing parameters are altered to obtain the optimum printing conditions (i.e. printing temperature, the build plate temperature, fan cooling and printing directions). The effect of the degree of crystallinity of semi-crystalline PET is investigated via altered printing parameters, showing superior mechanical properties for an increasing degree of crystallinity. To verify the portability of the obtained optimized print parameters, two different FFF printers are used. The use of recycled PET as feedstock for FFF supports the efforts for improving the sustainability of plastics by valorizing PET waste, and prolonging the lifecycle of PET

Effect of extrusion and fused filament fabrication processing parameters of recycled poly(ethylene terephthalate) on the crystallinity and mechanical properties

The production of plastic has grown exponentially over the past few decades and with it the amount of plastic waste leaking in the environment, where it fragments into micro-and nanoplastics. This problematic situation stresses the need for increased plastic collection, recycling and reuse rates. Extrusion-based additive manufacturing (AM) and especially fused filament fabrication (FFF) offer an efficient and effective method to reuse and upcycle recycled plastic. This study focuses on poly(ethylene terephthalate) (PET), which has a broad application window and its recycling is therefore environmentally and economically favorable and sustainable. Therefore, this study involves the thermal and mechanical behavior of recycled PET after extrusion and 3D printing. The extrusion parameters are optimized by performing a complete physico-chemical and thermal analysis of the obtained filaments and they were compared with commercial virgin and recycled PET. Moreover, the influence of the applied processing conditions on the degree of crystallinity and mechanical properties is investigated. The filaments are then used for FFF, where various printing parameters are altered to obtain the optimum printing conditions (i.e. printing temperature, the build plate temperature, fan cooling and printing directions). The effect of the degree of crystallinity of semi-crystalline PET is investigated via altered printing parameters, showing superior mechanical properties for an increasing degree of crystallinity. To verify the portability of the obtained optimized print parameters, two different FFF printers are used. The use of recycled PET as feedstock for FFF supports the efforts for improving the sustainability of plastics by valorizing PET waste, and prolonging the lifecycle of PET

New specialty polyesters from levulinic acid

International audienc