Dispersion coatings are offered as alternative solutions to extrusion coating technology for paper-based packaging. In addition to providing barrier properties, waterborne dispersions may implement the processing and converting properties of coated substrates, which are of extreme interest for an effective transfer to the industry. In this work, styrene-butadiene-based aqueous dispersions were formulated considering different amounts of kaolin as pigment. The authors assessed the heat-seal ability, fold cracking resistance, and blocking tendency, comparing the results against commercial dispersion coating grades. Kaolin content dominated the sealing behavior of experimental formulations, changing the minimum heat-seal temperature from 80 °C to >140 °C for 0% and 60% kaolin solid content, respectively. On the contrary, commercial grades were mostly affected by temperature. Additionally, despite the low latex glass temperature (0 °C), experimental formulations generally showed little, if any, blocking. On the downside, increasing kaolin content eases fold cracking, showing a different magnitude according to fold direction and coat orientation yet achieving a higher moisture barrier compared to commercial grades for both folded and unfolded samples.

In this work, different food‐contact experimental and commercial aqueous polymeric dispersions were applied to paperboard via rod coating technology to achieve <5% non‐cellulosic content. Barrier (water, moisture and grease), mechanical (tensile and bending) and converting (heat‐sealing and creasing) properties were analysed before tray formation trials on pilot‐scale equipment. Dispersion‐coated samples were compared against polyethylene terephthalate (PET) extrusion‐coated paperboard, the principal industrial material used for food trays. Results show that, within the investigated properties, waterborne dispersions can achieve similar barrier properties compared with PET, yet at lower dry coat grammage (12 g/m² vs. 40 g/m² of PET‐coated paperboard). Additionally, the investigated coatings heat‐sealed at temperatures as low as 80–90°C, almost 100°C less than PET; however, lower seal forces could be achieved (15–20 N/(25 mm) vs. 23 N/(25 mm) of PET‐coated paperboard). Paperboard delamination occurred at the highest seal forces. Dispersion‐coated trays were obtained at 4.5–5.0% blank moisture content. Formed trays at industrial processing parameters showed critical coating damage during converting due to tensile stresses. This work shows that milder processing conditions allow a reduction in coat defects.

Dispersion coating may represent an alternative technology to extrusion coating, currently dominating the market of coated paper-based packaging. Being processed as inks, dispersion coatings can be applied with conventional equipment, achieving lower dry coat grammages. In this work, two styrene-butadiene-based (T_g1 ≅ 0 °C; T_g2 ≅ 15 °C) dispersion coatings filled with different amounts of kaolin were developed and rod-coated on two different paper substrates. The samples were tested for water, moisture, and grease barrier properties. Kaolin-containing formulations showed moisture barrier as low as 15 g/(m²∙day), as well as grease barrier higher than 24 h. The best formulation involved 20% by weight of kaolin, whereas higher amounts were detrimental for water barrier, beneficial for moisture barrier, and slightly detrimental for grease barrier properties. Benchmarked to two commercial grades, kaolin-filled coatings strongly improved grease barrier, yet achieving similar moisture barrier.

Recently, corrugated cardboard furniture gained interest from the market, yet is limited to indoor application. With an aim toward outdoor usage, water-barrier improvement of such products must be achieved. In this work, three commercially available coating grades (i.e., polymeric, mineral-filled polymeric, and hybrid silica sol-gel products) were spray-coated on corrugated cardboard using a facile, yet readily transferable, process. The investigation assessed the coating performance from the different drying conditions and natural UV-vis weathering effects, characterising their water absorption, hydrophobicity, coating morphology, and colour change. Results show a reduction in water absorption values (up to −98%) for both the polymeric coatings; instead, the hybrid sol-gel coating showed contact angles up to almost 150°. Generally, the SEM micrographs displayed some surface defects as well as good thickness homogeneity. A perceivable colour change occurred for each sample (CIEDE2000 up to 6.41), mainly occurring in the 0–100 h time range. This work provides promising results for the outdoor application of corrugated cardboard furniture.

COVID-19 deeply changed traditional teaching, forcing the adoption of emergency remote teaching (ERT). ERT provided flexibility to teaching/learning activities (TLAs) yet affecting face-to-face communication and sociality. In this work, we present specific constructive alignment for an ERT/extended classroom course at Politecnico di Milano, as well as the tools involved. Two tutorials introduced the learners to the final essay, encouraged collaborative discussion, and promoted self-learning. The final essay, to be done individually or by joining a group, was part of the evaluation alongside a written exam. An evaluation rubric was shared when launching the topics of the essay, and setting the evaluation criteria. Results show how almost half of the essays were delivered by learners working alone, despite the attempts to promote collaborative interaction. Additionally, synchronous class attendance was only 55%, attributed to the availability of recordings and slides. Among the unattended results, the learners positively perceived TLAs and generated new collective knowledge, which was shared on the research group's Instagram profile.

The depletion of fossil resources, increasing packaging pollution, and stricter regulations require the development of sustainable alternative materials. This study presents POMOPLA², a fully bio‐based composite that enhances circularity by valorizing industrial tomato peel by‐products within a plasticized polylactic acid (PLA) matrix. A novel bio‐based and biodegradable plasticizer derived from oils was used to successfully reduce PLA brittleness, providing higher toughness (+485%) and strain at break (+177%), a lower glass transition temperature, while enhancing the compatibility of the tomato peels, used as reinforcement. The incorporation of tomato peel biomass has the potential to reduce production costs, and we showed that it can be used to modulate mechanical performance as well as aesthetics‐sensory attributes. Low percentages of tomato peels (5% w/w) maintained translucency for flexible film packaging applications, whereas higher contents (20% w/w) proved adequate mechanical properties for rigid packaging. POMOPLA² might implement a local circular economy in line with the European Circular Economy Action Plan, that is, to produce tomatoes' packaging to be potentially reintegrated into the biological cycle as compost, fostering a seamless nature‐to‐nature cycle.