Ancient code in polymers
György Marosi
Vol. 20., No.8., Pages 761-762, 2026
DOI: 10.3144/expresspolymlett.2026.57
DOI: 10.3144/expresspolymlett.2026.57
GRAPHICAL ABSTRACT

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DOI: 10.3144/expresspolymlett.2026.73
Vol. 20., No.10., Pages 990-1004, 2026
DOI: 10.3144/expresspolymlett.2026.73

Polyphenols represent a highly abundant group of plant-derived natural compounds, characterized by remarkable structural diversity and potent antioxidant activity. Based on their chemical structures, polyphenols are broadly categorized into flavonoids, phenolic acids, stilbenes, tannins and lignans. Among these polyphenolic groups, tannins stand out for their large and complex polyphenolic frameworks and strong metal-chelating abilities. Tannic acid, a well-known hydrolyzable tannin, is one of the most extensively utilized polyphenols because of its dense phenolic composition, strong metal-chelating ability and capacity to form diverse non-covalent interactions. This review highlights recent advancements and applications of tannic acid-based micro- and nano-formulations, with particular emphasis on their roles in emulsion stabilization, enhancement of UV-barrier properties and food safety sensor applications.
Effect of natural cinnamon extract on the stabilizing properties of biodegradable packaging polymers
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DOI: 10.3144/expresspolymlett.2026.5
Vol. 20., No.1., Pages 52-71, 2026
DOI: 10.3144/expresspolymlett.2026.5

The growing focus on sustainability, eco-friendly technologies, decarbonization, and reducing carbon footprints shapes current industry challenges. This article reviews the potential of cinnamon as a bio-additive for polymer stabilization in packaging. Samples were prepared from ethylene-norbornene copolymer (Topas), a cyclic olefin copolymer known for purity, transparency, and low gas permeability, and poly(lactic acid) (PLA), a bio-based alternative to petroleum plastics. Cinnamon powder was added in 0.5, 1.0, and 1.5 wt%. After solar and thermo-oxidative aging, hydrophobicity, chemical composition, mechanical, and color properties were analyzed. Results showed higher hydrophobicity and resistance to hydrolytic degradation due to reduced water penetration. PLA, normally brittle, became more flexible, with 0.5 wt% cinnamon showing optimal performance after 100 h of solar aging, similar to Topas composites. Overall, PLA and cyclic olefin copolymer (COC) films with cinnamon improved durability, extended food shelf life, and acted as natural color indicators of material aging.
Lilla Bubenkó, Násfa Németh, Sára Frey, Tamás Molnár, Károly Belina, Orsolya Viktória Semperger
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DOI: 10.3144/expresspolymlett.2025.55
Vol. 19., No.7., Pages 726-735, 2025
DOI: 10.3144/expresspolymlett.2025.55

Biocomposites have recently received more attention because of raising environmental awareness and the drive toward sustainable technologies. The most common biodegradable polymer is poly(lactic acid) (PLA), which has an excellent balance of physical and rheological properties, but there is some limit to its usage. PLA properties can be improved by adding different types of fibers or fillers that come from agricultural waste. In this study, corn cob and lavender stem were used to reinforce PLA without any coupling agent, and the properties of the composites were investigated. The melt flow rate (MFR) values decreased with the corn cob content and increased with the addition of lavender stem. Mechanical tests showed that the tensile and flexural modulus of the composites increased and the strengths decreased with the reinforcement material content. The rigidness of PLA slightly decreased with the addition of fillers. There was no significant effect on the thermal properties. The unremarkable improvement of the reinforcement was due to the lack of appropriate adhesion of the two phases. The structure of the compounds was found to be homogenous on the scanning electron microscopy (SEM) micrographs. The incorporation of corn cob and lavender stem can reduce the production cost of materials.
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DOI: 10.3144/expresspolymlett.2025.29
Vol. 19., No.4., Pages 386-408, 2025
DOI: 10.3144/expresspolymlett.2025.29

This review is focused on recent achievements in poly(lactic acid) (PLA) synthesis and copolymerization with special regard to biotechnological routes of PLA synthesis, which use bacteria/enzymes (e.g., enzymatic ring opening polymerization (eROP)). Besides PLA, also lactic acid (LA) synthesis is described and an emphasis is put on the biotechnological methods. Having regard to PLA copolymerization, this paper attempts to describe different types of PLA copolymers (such as block copolymers, PLA copolymers with polysaccharides, PLA-cellulose copolymer composites, and PLA polymer brushes). A detailed overview of the recent accomplishments in the field of PLA copolymers is presented. Various enhanced properties and applications of presented PLA copolymers are discussed. The attention is placed mainly on applications in the field of tissue engineering, drug delivery systems, and the packaging sector. Furthermore, a PLA market study and its economic forecast are presented. Eventually possible directions for future research in the field of PLA synthesis and copolymerization are indicated.
Ju Li, Lize Yang, Shuo Chen, Guotao Sun
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DOI: 10.3144/expresspolymlett.2025.4
Vol. 19., No.1., Pages 47-59, 2025
DOI: 10.3144/expresspolymlett.2025.4

The widespread use of cellulose nanofiber (CNF)-based aerogels is hindered by their limited flame retardancy and mechanical properties. This study addresses these challenges by developing cellulose nanofiber/sodium alginate/fly ash (CNF/SA/FA) aerogel through a one-pot method, utilizing industrial waste fly ash (FA) as a reinforcing material. Various characterization and analytical techniques were employed to evaluate the properties of the CNF/SA/FA aerogel. The findings have revealed that resulting aerogel exhibited excellent thermal insulation performance, with a thermal conductivity of 0.485 W/(m·K), along with an impressive compressive strength of 88.4 kPa and favorable shape processability. Vertical combustion tests demonstrated a V-0 rating, indicating superior flame retardancy, and the aerogel achieved a remarkable 79.16% residual carbon, confirming their effective heat shielding capabilities. Notably, the incorporation of FA significantly enhanced both the thermal and mechanical properties of the composite aerogel, presenting a sustainable and effective solution to optimizing the properties of aerogel for thermal insulation.



