From an environmental point of view, mechanical recycling is, in general, a good end-of-life option for poly(lactic acid) (PLA), one of the most important biobased polymers. However, the degradation of PLA during the service life and, especially, during the mechanical recycling process, leads to a decrease in the properties of PLA, thus reducing the applications of the recycled plastic. The main aim of this work was to study the addition of small amounts of halloysite nanotubes, during the recycling step, as the basis of a cost-effective method for improving the properties of the recycled PLA. Raw halloysite was modified with an aminosilane, and 2% by weight of both raw and modified halloysite were melt compounded with PLA previously subjected to accelerated ageing. The addition of the nanotubes led to recycled materials with improved properties because halloysite reduces the degradation of PLA by blocking the carboxyl groups, generated during the ageing and washing steps, which catalyze the degradation during the recycling process. This effect was more intense in the silanized nanotubes, because the carboxyl groups were effectively blocked by acid–base interactions with the amino groups of the chemical modification. The properties of the recycled plastic with only 2 wt% of silanized halloysite were very close to those of the virgin plastic., The authors would like to thank the Centro
Nacional de Microscopía Electrónica of the Universidad Complutense
de Madrid (Spain), for the collaboration in the TEM measurements.
This work was supported by MINECO-Spain (Grant Number
CTM2017-88989-P) and Universidad Politécnica de Madrid (project
UPM RP 160543006)., Peer Reviewed

Poly(lactic acid) (PLA) is one of the most important alternatives to fossil-fuel based polymers due to its biodegradability and good properties. However, the growing production along with the increasing resistance to degradation of the newer grades could lead to waste management problem. The application of mechanical recycling, which could be the best valorization method for biodegradation-resistant PLA residues, is limited by the degradation of the polymer, which decreases its performance, so it is interesting to develop simple and acceptable methods to improve the recycled plastic. The aim of this work is to study the effect of thermal treatments of PLA residues (with two levels of degradation) on the structure and properties of recycled PLA. During thermal treatments, both polycondensation and degradation reactions take place, and the net result depends on the degradation level of the residue and the time and temperature of the treatment. In adequate conditions, polycondensation reactions increase the molecular weight of the residue and lead to significant improvements of the mechanical and thermal properties of the recycled plastic. These results suggest that thermal treatments represent a simple, cost-effective and environmentally friendly method to improve the recyclability of PLA and, hence, the environmental impact of this plastic., Authors received funding from European Union's Horizon 2020
research and innovation program under grant agreement No.
860407 BIO-PLASTICS EUROPE, as well as from MINECO-Spain
(project CTM2017-88989-P) and Universidad Politécnica de Madrid
(project UPM RP 160543006).

Poly(lactic acid) (PLA) is one of the most used biobased and biodegradable polymers. Due to their high stability, some of the newest grades of PLA are only degradable under severe industrial conditions. For these grades, mechanical recycling is a viable end-of-life option, with great environmental advantages. However, the polymer undergoes degradation during its service life and in the melt reprocessing, which leads to a decrease in properties that can compromise the recyclability of PLA. The goal of this work was to evaluate the usefulness of adding small amounts of two organic fillers, chitosan, and silk fibroin nanoparticles, during the recycling process for improving the properties of the recycled plastic. The degradation level of the aged polymer and the nature and amount of filler affect the performance of the recycled plastics. The fillers reduce the degradation during the melt reprocessing of PLA previously subjected to severe hydrolysis, thus increasing the intrinsic viscosity of the recycled plastic. A careful selection of the added organic filler lead to recycled plastics with improvements in some key mechanical, thermal, and barrier properties. Thus, the use of organic fillers represents a cost-effective and environmentally sound way for improving the mechanical recycling of bioplastics., This work was supported by MINECO-Spain (pro-ject CTM2017-88989-P), Universidad Politécnica de Madrid (projectUPM RP 160543006), and the European Commission (Horizon 2020,project 860407-BIO-PLASTICS EUROPE). Dr. Lozano-Pérez’s researchcontract at IMIDA was partially supported (80%) by the ERDF/FEDEROperational Programme“Murcia”CCI N° 2007ES161PO001 (ProjectNo. 14-20/20)

Recently, the use of natural materials has grown in the plastics industry. In this study, novel bio-nanocomposites were developed from poly(lactic acid)/poly(ε-caprolactone) (PLA/PCL) blends and silk fibroin nanoparticles (SFNP). SFNP were successfully synthesized from silk fibroin (SF) and analyzed by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The obtained results revealed that the well-ordered structures in SF were changed to the amorphous structures in SFNP. Then (PLA/PCL) blends containing 10–30% of PCL were prepared and characterized. According to the obtained results, the PLA/PCL (70/30) blend was selected as the optimized sample for further studies. The scanning electron microscopy results illustrated that the addition of 1% of SFNP into this blend improved the compatibility between PLA and PCL and reduced the PCL droplet sizes from 1.170 ± 92 to 794 ± 46 nm. The results from TGA analysis indicated that the presence of SFNP enhanced the thermal stability of materials at high temperatures. The crystallization kinetics results revealed that while SFNP promoted the crystallization of neat PLA, the crystallization rate of PLA/PCL blend was decreased upon the incorporation of nanofiller. Furthermore, the PLA/PCL/SFNP exhibited higher microhardness and barrier properties than the neat blend. The results suggest that the developed bio-nanocomposites are promising materials for demanding applications such as food packaging., The authors thank Perstorp Co. Ltd., Sweden, for
supplying the PCL Capa™ 6800, MINECO-Spain (Project CTM2017-
88989-P) and Universidad Politécnica de Madrid (Project UPM RP
160543006). This project has received funding from the European
Union’s Horizon 2020 research and innovation program under Grant
Agreement No. 860407 BIO-PLASTICS EUROPE

The silk fibroin nanoparticles (SFNPs) were extracted from silkworm cocoons and used as a nanofiller in poly(lactic acid) (PLA)/poly(ε-caprolactone) (PCL) blend. The nanoparticle localization was studied theoretically and experimentally and the effects of SFNP on the morphology, rheology, toughness, and dynamic mechanical properties of the blend were investigated. According to the calculated wetting coefficient, SFNP should be thermodynamically located in the PLA matrix during the melting process. The results of SEM illustrated a common sea-island structure for the PLA/PCL blend and the incorporation of SFNP reduced the PCL domain sizes from 1.170 ± 92 μm to 794 ± 46 nm. The atomic force microscopy results showed that the nanoparticles are mainly located in the PLA matrix and also, partially at the phase interface with a thickness of layers around 80 nm. The rheological tests displayed the network formation of SFNP in the prepared nanocomposites. The dynamic mechanical analysis revealed that by the addition of SFNP, the storage modulus of neat PLA and PLA/PCL blend were increased by around 57 and 50%, respectively and the glass transition temperatures (Tg) values of PLA and PCL shifted toward each other. Additionally, using SFNP caused a lower water uptake and higher impact strength (~64%) of the blend., The authors would like to thank Perstorp Co. Ltd.,
Sweden, for supplying the PCL CapaTM 6800 and
MINECO-Spain (project CTM2017-88989-P). The European
Union’s Horizon 2020 support for performing some of tests
is appreciated.

3D printing PLA wastes were recovered from a well-known reference grade and from different sources. The recovered wastes were subjected to an energic washing step and then reprocessed into films by melt-extrusion, followed by compression molding to simulate the industrial processing conditions. The obtained materials were characterized and the optical, structural, thermal and crystallization behavior are reported. The mechanical recycling process leads to an increase of the crystallinity and a decrease of the intrinsic viscosity of the formulations, particularly in the sample based on blends of different 3D-PLA wastes. Moreover, the obtained films were disintegrated under composting conditions in less than one month and it was observed that recycled materials degrade somewhat faster than the starting 3D-PLA filament, as a consequence of the presence of shorter polymer chains. Finally, to increase the molecular weight of the recycled materials, the 3D-PLA wastes were submitted to a solid-state polymerization process at 110, 120, and 130 _C, observing that the recycled 3D-wastes materials based on a well-known reference grade experiences an improvement of the intrinsic viscosity, while that coming from different sources showed no significant changes. Thus, the results show that 3D printing PLA products provides an ideal environment for the implementation of distributed recycling program, in which wastes coming from well-known PLA grades can successfully be processed in films with good overall performance.

[EN] This work aims to study the effect of immersion in a ethanolic food simulant in mechanically recycled poly(lactic acid) (PLAR) and its nanocomposites reinforced with halloysite nanotubes (HNT). PLAR was obtained by subjecting PLA to an accelerated ageing process, which includes photochemical, thermal and hydrothermal ageing steps, followed by a final demanding washing step. PLAR was further reinforced with 4 %wt. HNT to improve the properties of the PLAR films. The materials were melt compounded by melt extrusion and processed into films by compression molding. The resulting films were exposed to food simulant D1 (50 %vol. ethanol solution) for 10 days at 40 °C. The intrinsic viscosity, crystallization behavior, thermal stability as well as the mechanical performance were analyzed before and after the contact with the food simulant. The swelling, plasticizing and hydrolyzing effect of the food simulant led to an important decrease of the intrinsic viscosity of all the samples, along with a significant increase of the crystallinity. Thermal stability was negatively affected by the decrease of the molecular weight, while the high crystallinity values resulted in materials with higher Vickers hardness values after the immersion in the food simulant., This work was supported by European Union’s Horizon 2020 research and innovation program [grant agreement No. 860407 BIO-PLASTICS EUROPE], by MINECO-Spain [project CTM2017-88989-P] as well as Universidad Politécnica de Madrid [project UPM RP 160543006].

[EN] Polybutylene adipate-co-terephthalate (PBAT) is a biodegradable polymer with good features for packaging applications. However, the mechanical performance and high prices of PBAT limit its current usage at the commercial level. To improve the properties and reduce the cost of PBAT, pine resin derivatives, gum rosin (GR) and pentaerythritol ester of GR (UT), were proposed as sustainable additives. For this purpose, PBAT was blended with 5, 10, and 15 wt.% of additives by melt-extrusion followed by injection moulding. The overall performance of the formulations was assessed by tensile test, microstructural, thermal, and dynamic mechanical thermal analysis. The results showed that although good miscibility of both resins with PBAT matrix was achieved, GR in 10 wt.% showed better interfacial adhesion with the PBAT matrix than UT. The thermal characterization suggested that GR and UT reduce PBAT melting enthalpy and enhance its thermal stability, improving PBAT processability. A 10 wt.% of GR significantly increased the tensile properties of PBAT, while a 15 wt.% of UT maintained PBAT tensile performance. The obtained materials showed higher hydrophobicity than neat PBAT. Thus, GR and UT demonstrated that they are advantageous additives for PBAT-resin compounding for rigid food packaging which are easy to process and adequate for industrial scalability. At the same time, they enhance its mechanical and hydrophobic performance., This research was funded by the Spanish Ministry of Economy and Competitiveness (MINECO), projects: PROMADEPCOL (MAT2017-84909-C2-2-R) and CTM2017-88989-P as well as by the European Union s Horizon 2020 research and innovation program under grant agreement no. 860407 BIO-PLASTICS EUROPE. M.A. thanks Secretaría de Educación Superior, Ciencia, Tecnología e Innovación (SENESCYT) and Escuela Politécnica Nacional (EPN). C.P. thanks Santiago Grisolía fellowship (GRISOLIAP/2019/113) from Generalitat Valenciana.

[EN] Poly(lactic acid) (PLA) was plasticized with maleinized linseed oil (MLO) and further
reinforced with sheep wool fibers recovered from the dairy industry. The wool fibers were firstly
functionalized with 1 and 2.5 phr of tris(2-methoxyethoxy)(vinyl) (TVS) silane coupling agent and
were further used in 1, 5, and 10 phr to reinforce the PLA/MLO matrix. Then, the composite materials
were processed by extrusion, followed by injection-molding processes. The mechanical, thermal,
microstructural, and surface properties were assessed. While the addition of untreated wool fibers to
the plasticized PLA/MLO matrix caused a general decrease in the mechanical properties, the TVS
treatment was able to slightly compensate for such mechanical losses. Additionally, a shift in cold
crystallization and a decrease in the degree of crystallization were observed due to the fiber silane
modification. The microstructural analysis confirmed enhanced interaction between silane-modified
fibers and the polymeric matrix. The inclusion of the fiber into the PLA/MLO matrix made the
obtained material more hydrophobic, while the yellowish color of the material increased with the
fiber content., This research was funded by MINECO under projects: PROMADEPCOL: MAT2017-84909-C2-2-R and CTM2017-88989-P as well as by European Union s Horizon 2020 research and innovation program under grant agreement no. 860407 BIO-PLASTICS EUROPE.