Abstract 2-Methylene-4H-benzo[d][1,3]dioxin-4-one, a cyclic hemiacetal ester prepared via the intramolecular esterification of acetyl salicylic acid, is an electron-rich vinyl monomer that can undergo radical polymerization to afford vinyl polymers with excellent thermal and mechanical properties. In this study, the aromatic ring was substituted with various substituents. Substitution with electron-donating groups resulted in instability and low yields, whereas substitution with two tert-butyl groups at the 6- and 8-positions increased the stability against moisture and reduced the reactivity in radical polymerization. Thus, the monomer afforded an almost ideal alternating copolymer with dimethyl maleate. Compared with the copolymers with nonsubstituted monomers, the copolymers with vinyl acetate presented a higher glass transition temperature, suggesting that the two tert-butyl groups effectively increased the thermal stability.

Abstract Petroleum-based plastics are lightweight and durable and exhibit excellent formability. However, the increase in global plastics production, coupled with the economic development of emerging countries, and the resulting marine pollution caused by plastic waste have become serious problems in recent years. Polysaccharides, such as starch and cellulose, are the most abundant biopolymers in nature and are particularly promising plastic alternatives owing to their renewability, sustainability, and biodegradability. However, owing to their lack of water resistance and adequate mechanical properties, large-scale application of polysaccharide films in single-use plastics is limited because water resistance is preferred in many daily scenarios. Further research is required to optimize bioplastics to make them economically and practically feasible. In this report, we focus on stimuli-responsive materials that form or dissociate cross-linked structures in response to slight changes in external stimuli or the environment. We developed starch-based films with different disintegration/dissolution rates in freshwater and seawater as environmentally friendly materials. Modified starch was mixed with oxidized cellulose or a water-soluble polymer to prepare a transparent, homogeneous film. After the introduction of hydrogen bonds, the starch complex film was stable in freshwater; however, in seawater, the hydrogen bond crosslinks dissociated, causing the film to dissolve rapidly. This technology balances degradability in marine environments with water resistance in everyday environments, providing an alternative means of reducing marine plastic pollution, and it is expected to be applied in a variety of industrial sectors.

Abstract Polymers and plastics pose environmental challenges, including marine pollution from waste and CO2 emissions from incineration. Recycling and upcycling are crucial strategies for conserving petroleum resources and reducing waste discharge. Additionally, developing sustainable polymers is essential for achieving a circular economy. Polymer degradation is a key process in both recycling and sustainable polymer development. This review examines the degradation of condensation polymers, such as polyesters and polycarbonates, when organic catalysts are used to enhance transesterification. Organic bases exhibit high catalytic efficiency in polymer degradation, whereas others facilitate the controlled polymerization of substituted cyclic esters and carbonates. Notably, 1,5,7-triazabicyclo[4.4.0]dec-7-ene has exceptional efficiency in degrading various condensation polymers, including aliphatic polycarbonates and liquid-crystalline wholly aromatic polyesters, via a dual hydrogen-bonding activation mechanism. The functionalization of aliphatic polycarbonates via side-chain modifications is a promising approach for producing functionalized degradable polymers, supported by efficient monomer synthesis and established ring-opening polymerization (ROP) techniques using organic catalysts. Precise polymer synthesis enhances mechanical and thermal properties by incorporating rigid moieties while enabling degradation control. These advancements contribute to the development of sustainable materials within a future circular economy.

The aim of this study was to investigate the biodegradation capacity of hydrophilic polyurethane-ureas (PUUs) containing fragments of 4,4′-diaminodiphenylmethane (DADPh) and a grafted copolymer polyvinyl alcohol–polyethylene glycol (PVA–PEG) in their structure under model conditions of the inflammatory process when in contact with blood. The biodegradation capability was evaluated by infrared (IR) spectroscopy, physical-mechanical testing, and differential scanning calorimetry (DSC) by monitoring changes in the structure, physical-mechanical, and thermophysical properties of the PUUs under the influence of the Fenton reagent over incubation periods of 1, 3, and 6 months. According to IR spectroscopy data, exposure to the Fenton reagent initiates an oxidative degradation process of the investigated PUUs, accompanied by the cleavage of specific chemical bonds, alterations in hydrogen bonding, and structural transformations of the polymer matrix. The physical-mechanical properties depend on the incubation duration in the Fenton reagent and change nonlinearly. After 6 months of incubation, compared to the control, an increase in strength and relative elongation at break was observed, which can be explained by the formation of new hydrogen bonds under the influence of the model medium. DSC results revealed that after incubation in the Fenton reagent, the PUU samples exhibited an increase in the glass transition temperature (Tg) and a jump in heat capacity (ΔCp) at the glass transition, indicating structural changes during the oxidative degradation process. Thus, the investigated materials demonstrate the process of oxidative biodegradation under the influence of a model medium. Therefore, PUUs containing fragments of the grafted copolymer PVA–PEG in their structure represent a promising polymer matrix for temporary medical applications.