Research articles

This study presented a noval material derived from poly(vinyl alcohol) (PVA), which was crosslinked with L-glutamic acid to improve the poor stability of PVA in water and modified with surface porosity introduced by poly(ethylene glycol) (PEG). The research primarily focused on elucidating the influence of PEG on the physicochemical properties of the material, which were governed by phase separation and hydrogen bonding interactions with PVA. The presence of porous structures significantly altered the material’s properties and enhanced its adsorption capacity toward copper(II) ions.

New acrylate and methacrylate monomers (1 and 2) incorporating a bulky and rigid norbornadiene dimer were synthesized and polymerized using borane- and aluminum-based Lewis pair catalysts. The resulting polymers exhibited high glass transition temperatures (T_g). Notably, poly2 exhibited high syndiotacticity (rr = 87%), attributed to steric hindrance of the bulky MAD-coordinated chain end, resulting in a T_g of 206 °C. These findings indicate that incorporating sterically demanding side chains and enhancing syndiatacticity through Lewis pair polymerization can lead to the development of thermally stable (meth)acrylic polymers.

Carboxy groups on cellulose nanowhiskers (CNWs) were quantified using two dyes in four states (original and purified methylene blue (MB) and toluidine blue O (TBO)). Only purified TBO yielded satisfactory accuracy. Unpurified TBO resulted in overestimation, attributed to impurities (typically inorganic salts), whereas unpurified and purified MB led to underestimation, the reasons for which are still unknown.

Substituting hydroquinone into polyallylamine allows the resulting organic redox polymer to achieve 99% of its theoretical capacity in aqueous electrolytes. A polymer-air secondary battery fabricated with this redox polymer as the electrode-active material exhibited a constant discharge voltage, high cyclability, and high rate capability. In addition, facile acid treatment decomposes the redox polymer into its raw materials. This work demonstrates a polymer design strategy for integrating typically hydrophobic organic redox molecules into recyclable aqueous batteries.

Cellulose acetate sponges were fabricated by cryo-templating, without chemical crosslinking, from cellulose acetate nanofilms produced using a nonsolvent-induced phase separation (NIPS)-jet spinning technique. X-ray computed tomography (X-CT) revealed their open-cell, continuous microstructure. The sponges exhibited resilience, stability, and mechanical tunability via microstructural tailoring. Their viscoelasticity was attributed to the bending of the cell structure and the delamination and slippage of the uncrosslinked nanofilms.

Mucin is a biological compound that consists of high-molecular-weight glycoproteins and plays an important role in the evaporation of water from respiratory droplets. The detailed structure of mucin has been clarified by static light scattering and the Fujita plot. The molecular weight is 2.92 × 10⁷, and the radius of gyration is 289 nm. The hydrodynamic radius is 198 nm, which was determined from multiangle dynamic light scattering. The scattering function reveals that mucin has a chain-like, elongated structure.

The crystal structure of the nylon-6 α form has been established on the basis of wide-angle X-ray diffraction data analysis. We have believed it for the past 70 years. However, the combination of X-ray and neutron diffraction data has required us to introduce the statistical disorderliness to the chain-packing mode as well as revise the space group to that of a higher symmetry. The refined crystal structure makes it possible to perform a more reliable quantitative analysis of the structure‒property relationship of the α form.

This study aimed to elucidate the mechanism underlying the release of micrometer-scale particles from transient networks using a systematically controlled model system composed of tetra-armed polyethylene glycol (Tetra-PEG slime). The system features a well-defined structure with uniform strand lengths and functionalities. Our results demonstrate that particle release is governed by the dissolution of the matrix and that the release barrier depends on the surrounding network topology. This release behavior is primarily determined by network connectivity and is independent of polymer concentration and strand length.

Biomass-derived tricomponent polymers were synthesized consisting of Levoglucosenone, aliphatic dithiol, and dicarboxylic dihydrazide. Sequential treatment of LGO with 1,4-butanedithiol followed by polycondensation with several dicarboxylic dihydrazides resulted in the formation of the corresponding polyhydrazones. All the C-S and C = N bonds were formed stereoselectively, which provided us their optical properties. In addition, these polymers also formed organogels with DMF after further heating. The degree of swelling varied between 170% and 469% depending on the carbon number of the dicarboxylic dihydrazide.

Graft copolymerization of a bifunctional monomer, triethylene glycol dimethacrylate (TEGDMA), onto deproteinized natural rubber (DPNR) was performed in latex stage using a redox initiator. It was found that TEGDMA could be grafted onto NR chain with low conversion and grafting efficiency. TEM revealed the formation of a continuous nanomatrix of poly(TEGDMA) surrounding the rubber particles. This nanomatrix enhanced structural integrity, gel content and slightly shifted the glass transition temperature. Thermal and mechanical properties, assessed by DSC, TGA, DMA, and swelling tests, demonstrated that polyTEGDMA significantly influenced the graft copolymer’s performance.

The entanglement dynamics of salt-free aqueous solutions of poly(sodium styrenesulfonate) was investigated using conventional bulk shear rheometry and diffusing wave spectroscopy microrheometry. Our scaling analysis of the entanglement concentration, plateau modulus, and relaxation time revealed a clear crossover from polyelectrolyte-like to neutral polymer-like behavior at a critical monomer concentration c_D ~ 0.3 M and a critical degree of polymerization N^* ~ 6000. We also found that the polymer concentration and molecular weight dependence of the tested entanglement parameters showed good agreement with the Dobrynin model.

A well-controlled ring-opening alternating copolymerization (ROAC) of cyclic anhydrides and isobutylene oxide (IBO) using organobase catalysts was developed. Using t-BuP₂ as a catalyst, the ROAC of phthalic anhydride (PA) and IBO proceeds smoothly, yielding crystalline P(PA-alt-IBO) with narrow molecular weight distribution (Đ ≤ 1.1). This method was extended to other cyclic anhydrides and initiators. Additionally, this ROAC system was applied to the synthesis of copolymers, including statistical copolymer and block copolymer. This study provides a straightforward and precise strategy for synthesizing crystalline polyesters and further macromolecular designs.

In this study, we used coarse-grained molecular dynamics simulations with iterative defect removal algorithm to investigate structure-properties relationship of star polymer networks (SPNs) and telechelic polymer networks (TPNs). SPNs possess a mechanism that eliminates loop defects during network formation, resulting in a greater number of elastically effective junctions than in TPNs. Despite the differences in cross-linking mechanisms, both network types exhibit shear moduli approximately twice the value predicted by the phantom network model using the effective closed cycle density, independently on the number of branches or the binding ratios.

Optical microscopy combined with a stretching stage allows the comparison of stress‒strain curves and real-time visualization of microscale structural changes in a microparticle-based polymer film under tensile testing. In films composed of inter-crosslinked microparticles, particle deformation deviated from affine behavior due to limited deformability. Local clusters of microparticles exhibited more location-dependent deformation, suggesting that the separation of neighboring particles contribute to film fracture.

A double-layer-coated slow-release fertilizer (DCSRF) was prepared with urea as the core, citric acid-modified starch and polyvinyl alcohol as the inner coating, and sodium alginate as the outer coating. Compared with the single-layer coated fertilizer (SCSRF), the DCSRF demonstrated superior slow-release effects, releasing 69.2% of the nutrients within 38 days in water. Additionally, adding 2% DCSRF to soil increased its maximum water-holding capacity by 8%. Pot trials revealed that the DCSRF considerably improved target crop growth, including tiller number, plant height, root depth, and leaf width, outperforming the other methods.

A π-conjugated Lewis acid dopant, branched octyloxy borane (BOB), was designed to modulate the solid-state microstructure of DPP-based polymers. BOB suppresses long-range crystallinity and promotes short-range aggregation via non-covalent interactions. At 1 wt%, it improves the crack onset strain from 20 to 100%, while retaining high carrier mobility over 1.0 cm² V^–1 s^–1. This strategy enables simultaneous enhancement of mechanical and electronic performance through dopant-induced morphology tuning.

Poly(ether ether ketone) (PEEK), a high-performance engineering plastic, was investigated to evaluate how its aggregation structure is influenced by crystallization pathway, cold crystallization and melt crystallization, and temperature affect. The degree of crystallinity increased with increasing crystallization temperature, while crystallographic lattice distortion decreased, regardless of the crystallization pathway. These results indicate that crystallization temperature plays a more dominant role than the pathway in determining the structure. The findings highlight the importance of thermal molecular motion during crystallization and provide valuable insights for optimizing the processing and design of semicrystalline engineering plastics.

Ring-opening copolymerization using the cyclic comonomer 3,7-bis(methylene)-1,5-dithiacyclooctane (BMDTO) introduces cleavable C–S bonds for chemical recyclability; however, it suffers from low molar mass via bulk free radical polymerization due to undesired radical transfer. To this end, this study leverages emulsion polymerization to produce polystyrene-BMDTO copolymers (1–7 mol% BMDTO), achieving higher molar mass (81 vs. 17 kg/mol) at 2.4 mol% BMDTO. Nuclear magnetic resonance spectroscopy and size exclusion chromatography confirm the incorporation and cleavability of BMDTO, establishing emulsion polymerization as a viable method for producing recyclable, high-performance vinyl copolymers.

A trifunctional five-membered cyclic carbonate resin synthesized from resveratrol (Res-TC) was thermally cured with diamines: trioxyethylene diamine (TODA), dioxyethylene diamine (DODA), m-xylene diamine (mXDA), pentamethylene diamine (PMDA), and Jeffamine ED-600. An adhesion test of the metal substrates revealed that cured Res-TC/TODA adhered strongly to metal substrates. After treatment with enzymes such as lipase and protease, some cured resins exhibited greater water uptake than did those treated with pure water, indicating that the enzymes cleaved the network of the cured resins and gradually decomposed the materials.

Cyclic ketene acetal esters derived from acetylsalicylic acid with various substituents on their aromatic rings were investigated. Substitution by two tert-butyl groups improved the stability of the monomer against moisture. Furthermore, the polymer solubility was increased by the flexible substituents, and the glass transition temperature was significantly increased owing to restricted bond rotation. The bulkiness of the tert-butyl group reduces the monomer reactivity, resulting in an almost ideal alternating copolymer with dimethyl maleate.