Printed and hybrid integrated electronics produced from recycled and renewable materials can reduce the depletion of limited material resources while obtaining energy savings in small electronic applications and their energy storage. In this work, bio-based poly(lactic acid) (PLA) and recycled polyethylene terephthalate (rPET) were fabricated in film extrusion process and utilized as a substrate in ultra-thin organic photovoltaics (OPV). In the device structure, metals and metal oxides were replaced by printing PEDOT:PSS, carbon and amino acid/heterocycles. Scalable, energy-efficient fabrication of solar cells resulted in efficiencies up to 6.9% under indoor light. Furthermore, virgin-PET was replaced with PLA and rPET in printed and hybrid integrated electronics where surface-mount devices (SMD) were die-bonded onto silver-printed PLA and virgin-PET films to prepare LED foils followed by an overmoulding process using the rPET and PLA. As a result, higher relative adhesion of PLA-PLA interface was obtained in comparison with rPET-PET interface. The obtained results are encouraging from the point of utilization of scalable manufacturing technologies and natural/recycled materials in printed and hybrid integrated electronics. Assessment showed a considerable decrease in carbon footprint, about 10–85%, mainly achieved through replacing of silver, virgin-PET and modifying solar cell structure. In outdoor light, the materials with low carbon footprint can decrease energy payback times (EPBT) from ca. 250 days to under 10 days. In indoor energy harvesting, it is possible to achieve EPBT of less than 1 year. The structures produced and studied herein have a high potential of providing sustainable energy solutions for example in IoT-related technologies.

Flexible and hybrid electronics (FHE) are widely utilized from wearable to automotive applications. Instead of commonly used poly(ethylene terephthalate) (PET) film, bio-based and biodegradable polymer, poly(lactic acid) (PLA), is a most promising novel substrate alternative for FHE. From the point of heat curable conductive inks, the poor heat resistance and inherent brittleness are the major drawbacks of PLA. By increasing the PLA film crystallinity through orientation and annealing, its properties can be improved. Two commercial grades, standard PLA (PLA) and a high heat PLA (hhPLA), plus one stereocomplex PLA (scPLA) blend were used to compare PLA performance with different optical purities and crystallinity for printed FHE. Machine direction orientation (MDO), biaxial orientation (BO) and annealing improved the stability of the laboratory and pilot scale manufactured PLA films. MDO was more effective in improving stiffness and strength while BO resulted in more ductile behaviour. In hhPLA the crystallinity increased from 0% to 50% improving tensile strength by 83%, tensile modulus by 52% and strain at break from 3.7% to 114% with 3 × 3 BO and annealing. The scPLA blend contained homo- and stereocomplex crystallites and a double melting peak behaviour provided higher temperature stability through final melting at 220°C. Its optical transparency reached 95%, remaining high up to 250 nm wavelength. In roll-to-roll printing, the PLA and hhPLA films were dried at 100°C prior the printing and this decreased the MD elongation from 2.55% and 0.27% to 0.00–0.05%. The sheet resistance of printed silver was <40 mΩ/sq with additional drying for printed and hybrid integrated light-emitting diode (LED) foils. Printed LED foils on PLA had dimensional and electrical performance comparable to PET, even though lower drying temperatures were used.

Depleting fossil resources and plastic pollution have generated an increasing demand for development of renewable and biodegradable polymers. Among other applications, packaging films are at the forefront of the scene. Poly(butylene succinate-co-adipate) (PBSA) is an interesting biopolymer due to its flexibility and good processability. However, its poor barrier properties limit the range of applications. On the contrary, poly(hydroxybutyrate) (PHB) biopolymer reveals good barrier performance, as well as stiffness and fast biodegradation rate. However, PHB drawbacks are its brittleness and difficult processability. By physical blending approach, a solution was delivered to overcome the shortcomings of these biopolymers, resulting in tailored properties of the films. PHB improved barrier performance of the blend film while flexible PBSA contributed to easier processability and better ductility. In this study, biobased and biodegradable blend films were produced in pilot-scale. The effects of PBSA/PHB blending were extensively studied by tensile testing, water and oxygen barrier testing, and thermal analysis. PBSA/PHB blend films exhibited improved Young’s modulus in comparison to neat PBSA. With 50 wt% PHB content, modulus of blend film was increased by 554% compared to pure PBSA film. The ductility of blend films decreased as a function of PHB content, becoming completely brittle at 50 wt%. It was found that barrier properties of PBSA/PHB films improved in comparison to neat PBSA. Oxygen transmission test results showed that oxygen permeability decreased as a function of PHB content. Similar trend was observed with water vapour permeation properties.

demonstrates the cell morphology of a biocomposite foam. The foam is made from chain extended PLA (polylactic acid) that contains 10% pulp fibers. The foam is produced with extrusion foaming using isobutane as foaming agent. The image is part of research which investigates how pulp fibers and different foaming agents (isobutane and carbon dioxide) affect the foamability and viscosity behavior of PLA in an extrusion foaming process. The research shows that addition of fibers to PLA foam reduces the average cell size while still maintaining low density and good cell morphology.

Technical and hygienic nonwovens, originating typically from fossil‐based synthetic polymers, are the fastest growing applications in the textile industry. Recently developed thermoplastic cellulose fatty acid esters have polyolefin like rheology properties and therefore the suitability of these cellulose esters for fiber production was evaluated. In this study, the melt spinning of textile fibers has been demonstrated using thermoplastic cellulose octanoate. The mechanical properties of melt spun fibers were analyzed by using tensile testing and both the surface and cross‐section morphology of melt spun fibers were studied using the scanning electron microscopy. The surfaces of the fibers were very smooth and also the cross‐section was very uniform and no porosity was observed. While mechanical properties of the produced fibers are not yet as good as those reported for commercial polypropylene (PP) monofilament fibers, they are somewhat more comparable to other cellulose ester‐based fibers. The melt spinning results indicate that the novel cellulose‐based fibers can provide a renewable and recyclable alternative, for example, spun‐laid PP in several hygienic textile and fully oriented in technical applications in future.