PLA is a widely employed biobased polymer in diverse fields such as food handling or biomedical applications [1] usually synthesized by Ring-Opening Polymerization (ROP). However, the current PLA applicability regarding thermal resistance, mechanical properties and crystallinity kinetics is slightly inferior to conventional petroleum-based polymers. Different strategies have been evaluated to improve the physicochemical properties such as the use of nucleating agents to increase the crystallization rate or the equimolar blend of PLLA and PDLA enantiomers to generate Stereocomplex (SC) crystallites, which features a melting point 50 °C higher than its homocrystals (HC) counterparts. However, the SC crystallization of the blended enantiomers diminishes for high molecular weight (HMw) PLA, and enantiomeric HC are obtained instead [2]. Herein, a novel series of the long-desired HMw stereo-diblock-copolymers of PLA were successfully synthesized by ROP using a heteroscorpionate catalyst without the need for a co-initiator [3], achieving a full stereocomplex crystallization. Moreover, the crystallization kinetics and morphology, of the designed SC-PLA-derivatives were enhanced to the highest known crystallization rate by the addition of a bioorganic nucleating agent (OXA2) to retain the bio-nature of the composite, which offers promising processing conditions to be scaled at industrial level. Furthermore, the customization of the tacticity and molecular weight through the well-controlled synthesis process, enables the generation of a series of PLA-derivatives exhibiting a wide range of thermodynamic and structural properties, as evidenced by a multitechnique analysis approach (DSC, SAXS/WAXS, Raman), which could potentially promote the personalization of medical applications through the structure-properties relationship and its final applications.

Growing environmental concerns regarding fossil-based plastics have intensified the transition towards a circular economy and more sustainable materials. Recycled polyethylene terephthalate (rPET) is increasingly utilized in fabrics, reducing carbon emissions and minimizing raw material dependency [1]. This study focuses on developing fibers for nonwoven applications using bio-PET, and rPET flakes with a high level of contamination, improving their properties through pre-industrial twin-screw extrusion. Thermal and oxidative stability was achieved by incorporating primary and secondary antioxidants, while an epoxy-based chain extender was employed to restore molecular weight and mechanical performance. Through rheological and thermal analysis, some formulations demonstrated thermal stability and strong fiber-forming potential, with intrinsic viscosity optimized to values between 0.4 and 0.8 dl/g. Soft-touch and antimicrobial additives were also incorporated to enhance suitability for medical devices, such as surgical gowns, while antioxidants played a key role in ensuring long-term stability, a critical factor for automotive applications. These findings highlight a pathway towards the development of innovative and sustainable fibers, enabling the production of nonwovens that meet both ecological and industrial demands.

Acknowledgements: This abstract was developed within the scope of the Innovation Pact “Sustainable Plastics”, co-financed by NextGenerationEU, through the Business Innovation Agendas’ investment from the Recovery and Resilience Plan (RRP) - Project no.3.

Piezoelectric materials are increasingly explored as self-powered platforms in regenerative medicine and tissue engineering. Poly-L-lactic acid (PLLA) is particularly promising for biomedical applications due to its biodegradability. However, its relatively low piezoelectric constant limits its practical application compared to polyvinylidene fluoride (PVDF) and its copolymers.[1] Therefore, there is a strong interest in developing new strategies to enhance the piezoelectric properties of green bioplastics. The microstructure of PLLA is based on repeating chiral L-lactic acid units, exhibiting C=O dipoles along the main chain. Although the most thermodynamically stable conformation is based on the random orientation of these dipoles, mechanical drawing induces the stretching of the polymer chains and the orientation of the dipoles in a preferential direction, activating its piezoelectric properties. Electrospinning is a simple and efficient method for the fabrication of highly oriented polymeric micro- and nanofibers with advanced properties.[2] Moreover, our research group has developed an extensive expertise in Ring-Opening Polymerization (ROP) using catalysts based on abundant metals, enabling the production of high-molecular-weight PLLAs with tailored D-isomer content. [3] In this study, we aim to produce highly aligned electrospun microfibers from PLLAs with different optical purities and molecular weights. In addition, we aim to study the key factors that influence their piezoelectric response as well as to compare the piezoelectric properties of the commercial and the synthetized PLLAs to evaluate the impact of these variations in the piezoelectric response.

Polymer engineers are interested in novel approaches for producing high-performance multicomponent systems. Although polymer blending is an appealing technique to obtain novel materials, most polymers are immiscible and/or incompatible. Reasons for incompatibility are high interfacial tension and poor interfacial adhesion. Development of multi-components products is based on the unique properties of interfaces which can be influenced by compatibilization techniques via modifying interfacial properties. In our work, a novel multi-polymeric material is achieved by characterizing and evaluating the effectiveness of a di-block compatibilizer on a Polyethylene / Semi-aromatic Polyamides immiscible blend. Different compatibilization paths are adopted as both a grafted compatibilizer and a di-block copolymer are used in different prepared blends via reactive extrusion. Then, rheological properties are studied using parallel plate shear rotational rheometer and compared with scanning electron microscope (SEM) imagery and interfacial tension measurements. Results show that storage (elastic) modulus increases with compatibilization reaching a saturation point where a 3D reinforcement effect is obtained. A droplet/matrix morphology is confirmed by Van Gurp-Palmen and cole-cole plots. Relaxation weighted spectrum marks the transition from two component mechanisms to a single unified relaxation mechanism. Thus, effective compatibilization is achieved as droplet size is reduced and dispersion enhanced. This study, therefore, confirms the compatibility of the two immiscible polymers using a di-block copolymer, which alters the melt flow properties and indicates a physical change.

Lignocelluloses, consisting of cellulose, lignin, and hemicellulose, have become promising materials of the bioeconomy due to their abundance, renewability, and accessibility with not only a broad presence in natural resources but also from waste. Lignocellulose has been utilized in various areas such as biomedical, electronics, and adhesive. This study reports the dispersion, phase behavior, and rheological properties of composite dispersions made of nanocellulose and lignin particles. First, aqueous cellulose nanocrystals (CNCs) dispersion was prepared at 3 wt. %, with rod-like particles showing liquid-like properties. Then, the two types of commercial lignin particles (hydrophilic and hydrophobic) were mixed into a nanocellulose network by two different methods: directly adding lignin powders and preparing aqueous lignin suspensions. Our results show that the same amount of hydrophilic lignin particles was homogeneously distributed in the CNC dispersion regardless of the preparation method. In contrast, agglomeration was detected in the hydrophobic lignin-CNC dispersion. Also, lignin particles created a porous network with CNC and doubled the lignin amount, decreasing the pore sizes according to SEM images. Rheological measurements revealed that all lignin forms increased the viscosity and the storage modulus of the CNC proportional to the concentration due to the denser network formation between them. This work reveals that lignin chemistry and mixing way affect the network formation with CNC and flow properties of the green composites, which are crucial to obtaining biocomposites.

The accumulation of fossil-based, non-biodegradable, and non-recyclable polymers in the environment is a major global concern. By 2050, plastic waste is projected to exceed 10 billion tons. Among renewable resource-based polymers, poly(lactic acid) (PLA) has gained significant attention due to its comparable thermal properties to fossil-based polymers and its environmentally friendly large-scale production [1]. This study aims to develop non-toxic, eco-friendly substrates as alternatives to fossil-based materials in printed electronics (PE), where electronic waste is one of the fastest-growing solid waste streams worldwide [2].
To tailor PLA properties, copolymerization was chosen as a to produce flexible biobased copolyesters using poly(ethylene azelate) (PEAz) for PE applications. PLA-b-PEAz blocky copolyesters were synthesized via ring-opening polymerization (ROP) of L-lactide. Four comonomer mass ratios were used: 97.5-2.5, 95-5, 90-10, and 80-20. All copolyesters exhibited molecular weights ranging from 10 to 80 kg/mol. Mechanical testing showed enhanced elongation and high Young’s modulus values, indicating a balance of toughness and flexibility.
To further enhance mechanical properties, annealing, and biaxial stretching experiments were conducted using an in-house stretch crystallization apparatus. Surface properties were evaluated through adhesion measurements using different inks on PLA-based and commercial PET substrates. Results suggest that the PLA-based substrates are promising alternatives for PE applications.

Acknowledgements
Funded by the European Union under the GA no 101070556. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or RIA. Neither the European Union nor the granting authority can be held responsible for them.