Chinese Journal of Polymer Science最新文献

In rotationally extruded fittings, high-density polyethylene (HDPE) pipes prepared using conventional processing methods often suffer from poor pressure resistance and low toughness. This study introduces an innovative rotary shear system (RSS) to address these deficiencies through controlled mandrel rotation and cooling rates. We successfully prepared self-reinforced HDPE pipes with a three-layer structure combining spherical and shish-kebab crystals. Rotational processing aligned the molecular chains in the ring direction and formed shish-kebab crystals. As a result, the annular tensile strength of the rotationally processed three-layer shish-kebab structure (TSK) pipe increased from 26.7 MPa to 76.3 MPa, an enhancement of 185.8%. Notably, while maintaining excellent tensile strength (73.4 MPa), the elongation at break of the spherulite shishkebab spherulite (SKS) tubes was improved to 50.1%, as compared to 33.8% in the case of shish-kebab spherulite shish-kebab (KSK) tubes. This improvement can be attributed to the changes in the micro-morphology and polymer structure within the SKS tubes, specifically due to the formation of small-sized shish-kebab crystals and the low degrees of interlocking.In addition,2D-SAXS analysis revealed that KSK tubes have higher tensile strength due to smaller crystal sizes and larger shish dimensions, forming dense interlocking structures. In contrast, the SKS and TSK tubes had thicker amorphous regions and smaller shish sizes, resulting in reduced interlocking and mechanical performance.

Development of polymers with underwater self-healing and antifouling properties is crucial, particularly in harsh marine environments. In this study, polydimethylsiloxane (PDMS)-based antifouling polymers with tunable self-healing capabilities in aqueous conditions were fabricated by incorporating amphiphilic segments and Fe³⁺-catechol dynamic coordination crosslinking. The microphase formed within the PDMS matrix imparted static antifouling properties to the coatings. The mechanical properties of the damaged sample were restored at room temperature in an aqueous environment for 24 h, achieving a self-healing efficiency of almost 100%. The synthesized material exploited the dynamic coordination between Fe³⁺ and catechol to facilitate underwater self-healing. No bacterial adhesion was observed at the scratch site after the coating was repaired. This material enables the long-term antifouling and autonomous repair of marine vessels and sensors, thereby reducing maintenance costs.

An inverse vulcanized polymer, SZIM combining Zn²⁺-imidazole coordination bonds and polysulfide bonds was synthesized and incorporated into bio-based Eucommia ulmoides gum (EUG) to generate EUG-SZIM-xs. The residual crystallinity of the EUG matrix synergistically interacted with the dual cross-linking networks to establish reversible deformation domains, providing EUG-SZIM-xs with quick shape memory capability at moderate temperatures. The damping properties were also investigated, and EUG-SZIM-xs displayed high tanδ values (>0.3) when the SZIM dosage was higher than 5.5 phr, which showed a positive correlation with SZIM concentration. Such good damping performance endowed the EUG-SZIM-xs with broadband low-frequency sound absorption. In addition, the dual cross-linking networks endowed the materials with reprocessability under different catalytic systems, and the 1,8-diazobicyclic[5.4.0]undeca-7-ene (DBU)-catalyzed samples exhibited better mechanical properties than EUG-SZIM-xs.

Herein, the effect of in situ formation of the stereocomplex polylactide (sc-PLA) on the crystallization behaviors of poly(L-lactide)/poly(D-lactide) (PLLA/PDLA) blends was assessed. When the melt-blending temperature of the PLLA/PDLA blend approached the melting temperature of sc-PLA (approximately 220 °C), a higher relative content of sc-PLA was achieved. Additionally, the relative content of sc-PLA in the PLLA/PDLA blend increased progressively with the increase in PDLA content. Differential scanning calorimetry analysis revealed that the overall crystallization rate of the homocrystal polylactide were enhanced by the presence of sc-PLA. After crystallization at the same temperature (115 and 120 °C), the PLLA/PDLA blends exhibited a shorter half-crystallization time compared to PLLA alone. The size of the microcrystals of PLLA decreased as the sc-PLA content increased. Furthermore, the storage modulus and complex viscosity of the PLLA/PDLA blend increased with higher sc-PLA content. Dynamic mechanical analysis indicated that the glass transition temperature of PLLA in the PLLA/PDLA blends increased with increasing sc-PLA content. Additionally, the Vicat softening temperature increased from 67.8 °C for PLLA alone to 164.7 °C for the PLLA/25PDLA blend, enhancing the heat resistance of the PLLA/PDLA blends. Compared to PLLA alone, the hydrolytic resistance of the PLLA/PDLA blends showed marked improvement.

Supramolecular materials that combine toughness, transparency, self-healing, and environmental stability are crucial for advanced applications, such as flexible electronics, wearable devices, and protective coatings. However, integrating these properties into a single system remains challenging because of the inherent trade-offs between the mechanical strength, elasticity, and structural reconfigurability. Herein, we report a supramolecular ionogel designed via a simple one-step polymerization strategy that combines hydrogen bonding and ion-dipole interactions in a physically crosslinked network. This dual-interaction architecture enables the ionogel to achieve high tensile strength (9 MPa), remarkable fracture toughness (23.6 MJ·m⁻³), and rapid self-healing under mild thermal stimulation. The material remains highly transparent and demonstrates excellent resistance to moisture, acid, and salt environments, with minimal swelling and performance degradation. Furthermore, it effectively dissipates over 80 MJ·m⁻³ of energy during high-speed impacts, providing reliable protection to fragile substrates. This study offers a broadly applicable molecular design framework for resilient and adaptive soft materials.

Understanding the mechanisms that influence the formation of stereocomplex crystals (SCs) in poly(lactic acid) (PLA) is critical for achieving effective regulation of SC content. In the current simulations, we constructed polymer blends with different initial chain conformations and then obtained four groups of polymer blend systems with similar segment miscibility but different chain extension degrees by controlling the high-temperature relaxation time. The simulation results indicate that the fraction of SCs formed in these systems is closely correlated with the average mixing parameters during the crystallization process rather than the initial chain extension degrees. In other words, the average segment miscibility in the crystallization process is the key factor controlling the formation ability of SCs.

The optimization of polymer structures aims to determine an optimal sequence or topology that achieves a given target property or structural performance. This inverse design problem involves searching within a vast combinatorial phase space defined by components, sequences, and topologies, and is often computationally intractable due to its NP-hard nature. At the core of this challenge lies the need to evaluate complex correlations among structural variables, a classical problem in both statistical physics and combinatorial optimization. To address this, we adopt a mean-field approach that decouples direct variable-variable interactions into effective interactions between each variable and an auxiliary field. The simulated bifurcation (SB) algorithm is employed as a mean-field-based optimization framework. It constructs a Hamiltonian dynamical system by introducing generalized momentum fields, enabling efficient decoupling and dynamic evolution of strongly coupled structural variables. Using the sequence optimization of a linear copolymer adsorbing on a solid surface as a case study, we demonstrate the applicability of the SB algorithm to high-dimensional, non-differentiable combinatorial optimization problems. Our results show that SB can efficiently discover polymer sequences with excellent adsorption performance within a reasonable computational time. Furthermore, it exhibits robust convergence and high parallel scalability across large design spaces. The approach developed in this work offers a new computational pathway for polymer structure optimization. It also lays a theoretical foundation for future extensions to topological design problems, such as optimizing the number and placement of side chains, as well as the co-optimization of sequence and topology.

In recent years, cellulose-based fluorescent polymers have received considerable attention. However, conventional modification methods face challenges such as insolubility in most solvents, fluorescence instability, and environmental risks. In this study, a novel biosynthesis strategy was developed to fabricate fluorescent cellulose by adding fluorescent glucose derivatives to a bacterial fermentation broth. The metabolic activity of bacteria is utilized to achieve in situ polymerization of glucose and its derivatives during the synthesis of bacterial cellulose. Owing to the structural similarity between triphenylamine-modified glucose (TPA-GlcN) and glucose monomers, the TPA-GlcN were efficiently assimilated by the bacterial cells and incorporated into the cellulose matrix, resulting in a uniform distribution of fluorescence. The fluorescence color and intensity of the obtained cellulose could be adjusted by varying the amount of the fluorescent glucose derivatives. Compared to the fluorescent cellulose synthesized through physical dyeing, the fluorescence of the products obtained by in situ polymerization showed higher intensity and stability. Furthermore, fluorescent bacterial cellulose can be hydrolyzed into nanocellulose-based ink, which demonstrates exceptional anti-counterfeiting capabilities under UV light. This biosynthesis method not only overcomes the limitations of traditional modification techniques but also highlights the potential of microbial systems as platforms for synthesizing functional polymers.

Polymer acceptor configuration and aggregation behavior are critical in determining the photovoltaic performance of all-polymer solar cells (all-PSCs). Effectively manipulating polymer self-aggregation through structural design to optimize the blend morphology remains challenging. Herein, we present a simple yet effective design strategy to modulate the aggregation behavior of the Y-series-based polymer acceptor PY-V-γ by introducing a pendant-fluorinated Y-series acceptor (Y2F-ET) into the main-conjugated backbone. Two random copolymer acceptors (PY-EY-5 and PY-EY-20) were synthesized with varying molar fractions of Y2F-ET pendant monomers. Our findings revealed that both the solution-phase and solid-state aggregation behaviors were progressively suppressed as the Y2F-ET content increased. Compared to the highly self-aggregating PY-V-γ-based all-PSCs, the more amorphous PY-EY-5 enabled devices to achieve an increased device efficiency from 17.31% to 18.45%, which is attributed to the slightly smaller polymer phase-separation domain sizes and reduced molecular aggregation in the PM6:PY-EY-5 blend. Moreover, the finely tuned blend morphology exhibited superior thermal stability, underscoring the significant advantages of the Y-series pendant random copolymerization approach.