Humanoid robots represent a pivotal physical carrier for embodied intelligence, demonstrating significant developmental potential and broad application prospects. Polymers, featured by the merits such as low density, high specific strength, ease of processing, and tunable functionality, are increasingly being utilized in load-bearing and functional components of humanoid robots. This article reviews recent research achievements in polymers for humanoid robotic applications. Placing focus on key performance requirements for lightweight skeletal structural materials, bionic skin materials, and intelligent sensing-actuation materials, this review elaborates on advances in microstructural design, functional network construction, preparation and processing methods, as well as structure-property relationships. Finally, current challenges and future development directions in this field are discussed and summarized.

Biomass-based self-healing polymers combine the sustainability of renewable resources with intelligent repair capabilities, demonstrating unique promise for advancing green materials. In recent years, with the rapid progress in dynamic chemistry, the construction of self-healing materials from biomass has become an important research direction in polymer science, which not only expands the functional boundaries of traditional polymers but also provides new pathways for material recycling and lifespan extension. This review systematically outlines the design strategies of biomass-based self-healing polymers, focusing on the design principles and healing mechanisms of dynamic covalent bonds (e.g., imine, disulfide, and boronic ester bonds), dynamic non-covalent interactions (e.g., hydrogen bonding, metal coordination, and electrostatic interactions), and synergistic multi-dynamic bonding systems. Furthermore, self-healing polymer systems developed from various biomass sources, including polysaccharides (such as cellulose, starch, and chitosan), lignin, vegetable oils, proteins, natural rubber, Eucommia ulmoides gum, and other distinctive biomaterials (e.g., DNA, tea polyphenols, itaconic acid, and lipoic acid), are summarized. The healing behaviors and performance characteristics of these materials under different stimuli (e.g., heat, light, moisture, and pH) were analyzed. These materials have broad application potential in fields such as flexible electronics, biomedical devices, smart coatings, sensors, and sustainable packaging. Finally, the challenges and future development trends in this emerging field are discussed.

Carbon fiber-reinforced phthalonitrile (CF/APN) composites suffer from low through-thickness thermal conductivity, which limits their application in high thermal conductivity fields. To address this issue, in this work, two types of phthalonitrile resin (APN) microspheres with average particle sizes of 25 μm and 200 μm were first prepared via reaction-induced phase separation. Subsequently, few-layer graphene (FLG) was coated on the surface of the microspheres to obtain APN25@FLG and APN200@FLG core-shell particles. These APN@FLG particles were introduced into the CF/APN composite system as thermally conductive fillers, and their effects were compared with the direct addition of FLG. The regulation of core-shell particles on the thermal conductivity of composites and their influence on mechanical properties were systematically investigated. The results demonstrated that the modification strategy incorporating APN@FLG particles exhibited a significantly superior thermal conductivity enhancement effect over the direct addition of FLG. The APN resin microspheres in APN@FLG could effectively impede the in-plane orientation of FLG under molding pressure, thereby remarkably improving the through-thickness thermal conductivity of the composites. At an FLG loading of 3.6 wt%, the through-thickness thermal conductivity of the APN200@FLG/CF/APN composite reached 1.62 W/(m·K), representing a 189% increase compared to the unmodified CF/APN composite. Meanwhile, the interlaminar shear properties of the composites remained largely unchanged after the introduction of APN@FLG particles, while the flexural strength decreased slightly only at relatively high particle loadings. This study provides an efficient and feasible novel strategy for the design and preparation of high-performance thermally conductive composites.

To address the deterioration of polyester quality caused by the dehydration etherification of bis(2-hydroxyethyl) terephthalate (BHET) during polyester synthesis from coal-based ethylene glycol (EG), the esterification behavior of coal-based EG with terephthalic acid was systematically investigated. The target product BHET and various by-products formed during the esterification reaction were structurally characterized by proton nuclear magnetic resonance spectroscopy (¹H-NMR) and liquid chromatograph-tandem mass spectrometry (LC-MS/MS). These by-products included BHET dimers and trimers, as well as BHET monomers, dimers, and trimers terminated with bis[2-(2-hydroxyethoxy)ethyl] groups. The results revealed the characteristic esterification behavior of coal-based EG. Tetrabutyl titanate was employed as a catalyst to suppress etherification side reactions. Combined with solubility differences and thin-layer silica gel filtration, BHET was effectively separated and purified. The purity of the obtained BHET reached 99.14%, and the residual titanium content was reduced to 147 μg/g. Fiber-grade poly(ethylene terephthalate) (PET) was prepared via polycondensation of the purified BHET and subsequently processed into polyester fibers by melt spinning. The tensile strength and elongation at break of the obtained fibers were comparable to those of fibers prepared from commercial BHET under the same polymerization and spinning conditions. These results demonstrate that, through appropriate esterification catalysis and BHET purification, coal-based ethylene glycol shows strong potential for application in the production of polyester fibers.

High-performance optical resins are increasingly vital for advanced applications such as high-definition lenses and optoelectronic devices, yet simultaneously achieving high refractive index and high Abbe number remains a significant challenge. This study presents a metal-free, one-pot terpolymerization strategy to synthesize random poly(ester-carbonate)s from CO₂, epoxides (cyclohexene oxide or vinyl cyclohexene oxide), and bio-based tricyclic anhydrides using a triethylborane (TEB)/bis(triphenylphosphine) iminium chloride (PPNCl) Lewis pair catalyst system. The resulting copolymers exhibit a high number-average molecular weight (M_n) of up to 148.6 kg/mol. By adjusting the epoxide/anhydride feed ratio, the glass transition temperature (T_g) can be tuned from 114 ℃ to 142 ℃, with thermal decomposition temperatures exceeding 219 ℃. Notably, the incorporation of the rigid, saturated tricyclic skeleton enables the resins to achieve a high refractive index (n_d=1.50-1.52) while maintaining a high Abbe number (V_d=46-57), overcoming the trade-off typically found in organic optical materials. The films prepared via drop-casting demonstrate excellent transparency (>91%). This work provides a green, efficient pathway for developing high-performance, metal-free optical materials with superior thermal and optical properties.

To address the insufficient understanding of how amide bond incorporation affects the kinetic pathways of chemical imidization and the subsequent evolution of the structure and properties of polyimides, colorless polyimide (CPI) and copolyamide-imide (CPAI) were selected as model systems. The effects of amide bond incorporation and dehydrating agent content (60%~160%) on the kinetics of chemical imidization, the aggregated structure after complete imidization, and the mechanical and optical properties of the films were systematically investigated. The results showed that incorporating amide bonds significantly altered the kinetic pathway of chemical imidization. In the CPI system, the reaction changed from second-order kinetics to first-order kinetics when the dehydrating agent content exceeds 120%. In contrast, the CPAI system exhibited first-order kinetics at 60%~100% due to the intramolecular hydrogen-bonding-induced "built-in catalysis" effect, whereas it reverted to second-order kinetics above 120% as the hydrogen-bonding network was weakened. The difference in the kinetic pathways further affected the evolution of the aggregated structure of the films. X-ray diffraction and birefringence analyses revealed that increasing the dehydrating agent content promoted denser chain packing and enhanced in-plane orientation, thereby enabling the synergistic improvement of the mechanical and optical properties of CPI films. When the dehydrating agent content was ≥120%, the tensile strength, elongation at break, and transmittance at 550 nm of CPI films reached 130.3 MPa, 10.3%, and 89.8%, respectively. In contrast, CPAI films exhibited higher toughness, and their optical properties were further improved owing to the enhanced film uniformity. This work provides a theoretical basis for regulating the chemical imidization process and optimizing the overall performance of CPI/CPAI films.

In recent years, porous hydrogels have demonstrated broad application prospects in fields such as drug delivery, tissue engineering, and flexible sensors, due to their highly tunable pore structure, large specific surface area, low density, and deformability. However, influenced by high porosity and high water content, porous hydrogels often suffer from insufficient mechanical properties. To address this challenge, we proposed a strategy based on the synergistic effect of salting-out and multiple crosslinking for preparing high-strength and high-toughness porous hydrogels. Utilizing the hydrogen gas generated by the in situ redox reaction between gallium-based liquid metal (LM) and the aqueous medium, rapid foaming of the system was driven to form a porous structure. Combined with hydrophobic association induced by the salting-out effect and the interaction of multiple physical-chemical crosslinks such as dynamic borate ester bonds, metal ion coordination bonds, and hydrogen bonds, an LMCNF porous hydrogel with high strength, high toughness, and high conductivity was fabricated. Experimental results showed that under optimal preparation conditions with an LM (7.5 wt%), PVA (16 wt%), and sodium citrate solution (20 wt%), the LMCNF porous hydrogel achieved a tensile strength of 1009.47 kPa, toughness of 1520.6 kJ/m³, elongation at break of 266.06%, and electrical conductivity of 8.39 mS/cm. Furthermore, the hydrogel exhibited a sensitive, stable, and reversible resistance response during compression, with a high gauge factor (GF up to 1.68) and a wide operating range. It also demonstrated excellent cyclic compression stability and fatigue resistance, maintaining its initial morphology after 100 compression cycles at 70% compressive strain. These characteristics highlight its potential applications in flexible electronic devices, smart sensors, and health monitoring.

A variety of indoor accelerated aging experiments were conducted to study the aging behavior of polyolefin elastomer (POE) encapsulation films under conditions such as thermal oxygen, damp heat, xenon lamps, and iodized gallium lamps, and to explore the sensitivity of POE encapsulation films to different aging factors. By characterizing the changes in mechanical properties, crosslinking degree, optical properties, thermal stability, surface morphology, chemical structure, etc., the changes in macroscopic properties and microstructure before and after aging were evaluated. The aging mechanism and additive precipitation behavior of POE under different aging conditions were compared and analysed. It was found that under thermal oxygen conditions, there is a competition between oxidative degradation and post-crosslinking, resulting in no significant change in macroscopic properties. Photo-oxidative aging showed a significant accelerating effect on the degradation of molecular chains. Xenon lamps with low irradiation showed the most severe oxidative degradation after aging, while iodized gallium lamps with high irradiation led to the break of molecular chains after aging. The temperature and humidity of the environment affected the precipitation ability of small-molecule additives in the material matrix. Under high-temperature or high-humidity conditions, the precipitation phenomenon of additives was more obvious, thereby affecting the anti-aging ability of the material.

Using dimethyl oxalate (DMO), dimethyl carbonate (DMC), and 1,4-butanediol (BDO) as raw materials, a series of high-molecular-weight poly(butylene oxalate-co-butylene carbonate) (PBOC) were successfully synthesized via a two-step transesterification polycondensation method, the effect of the butylene carbonate (BC) segment content on the structure and properties of PBOC was investigated. It was found that PBOC was a random copolymer of BC and poly(butylene oxalate) (PBO), exhibiting a single glass transition temperature (T_g), which decreased with increasing BC content. The introduction of BC segments would disrupt the regularity of the PBO molecular chains, significantly inhibiting the crystallization ability of PBO, and the melting temperature, crystallinity, and crystallization rate of PBOC all decreased with increasing BC content. The mechanical properties, barrier properties, and degradation performance of PBOC could be effectively controlled by adjusting the BC content. When the BO content is 80%, the obtained PBO₈₀C achieved a tensile strength of 48 MPa and an elongation at break of 600%. Taking the permeability coefficient of commercial poly(butylene succinate-co-terephthalate ) (PBST) as a reference, the barrier improvement factors of PBO₈₀C for O₂ and H₂O, BIFp (O₂) and BIFp (H₂O), are 6.4 and 5.2, respectively, much higher than those of other commercial copolyesters. This study provides a valuable reference for the research and development of high-performance biodegradable materials.

To address the insufficient load-bearing capacity and poor friction stability of poly(ether ether ketone) (PEEK) under severe conditions, a multiscale synergistic reinforcement system combining carbon fibers (CF) and carbon nanotubes (MWCNTs) with interfacial chemical modification was developed. Polyetherimide (PEI) and third-generation poly(amidoamine) (PAMAM) dendrimers were employed to functionalize the CF surface, enabling uniform anchoring of MWCNTs via sizing and grafting. The results showed that stable covalent bonding was formed at the interface, significantly enhancing interfacial adhesion and load transfer. Compared with neat PEEK, the composites exhibited improved hardness and thermal conductivity, with CF-PAMAM-MWCNTs/PEEK showing the best overall performance. At 130 N, its friction coefficient and wear rate decreased by 15.8% and 31.97%, respectively, while the wear rate was reduced by 65%-75% within 3-9 mm·s^-1. The enhanced tribological performance was attributed to the multiscale synergistic effect and the formation of a stable tribofilm, which effectively suppress fiber pull-out and three-body abrasion.

The high-performance development of ultra-high molecular weight polyethylene (UHMWPE) fibers has long been a central issue in high-strength and high-modulus polymer fibers, while the cooperative roles of raw material molecular weight, microstructure, and complex processing pathways remain insufficiently understood. In this study, spinning-grade UHMWPE resins with different molecular weights were investigated, focusing on gel spinning and multistage drawing as representative nonequilibrium processing routes. The relationships among the raw material structure, chain topological evolution, and drawing behavior were examined. It was found that increasing the molecular weight of the raw material alone did not directly improve the mechanical properties of the fiber; instead, its potential contribution was released through chain disentanglement and orientation reorganization during processing. Resins with a concentrated particle size distribution and moderate pore structures were more favorable for homogeneous swelling and the formation of stable gel network structures. By coordinating the screw temperature and rotational speed, the molecular weights of the gel fibers derived from different initial viscosity-average molecular weights were regulated and converged to approximately 3.60×10⁶ g/mol. However, different temperature-shear pathways introduced path-dependent nonequilibrium chain topologies, which persisted during subsequent drawing as topological memory effects and continuously influenced the chain flexibility and fiber mechanical performance. Systems with higher chain flexibility, particularly those with intermediate molecular weights, were more suitable for achieving a high draw-ratio orientation. Overall, the results suggest that the high-performance fabrication of UHMWPE fibers depends on the cooperative regulation of chain topology and drawing kinetics rather than molecular weight maximization alone, providing a basis for structure-process design in UHMWPE fiber manufacturing.

Close-packed structure, owing to the coexistence of tetrahedral and octahedral voids, leads to a very narrow stable phase region in the pure AB diblock copolymers. Moreover, previous studies have shown that in the simple AB diblock copolymers, the stable close-packed spherical phase is only the hexagonal close packed (HCP) structure. In this work, we employed the self-consistent field theory (SCFT) to investigate the phase behavior of AB/B binary blends. The results demonstrated that this blending strategy can effectively broaden the stability region of close-packed spherical phases. Furthermore, it was found that, at appropriate concentrations and chain length of the added homopolymers, the face centered cubic (FCC) phase was more stable than the HCP phase. This transition was attributed to the enhanced "local segregation" between the B-blocks and B-homopolymers as the increasing concentration and chain length of the homopolymer, which promoted the formation of FCC structures with larger spherical domains and unit cell sizes. This study provides theoretical guidance for the experimental fabrication of similar nanostructures with specialized functionalities.

To address insulation aging and breakdown issues in high-voltage electrical equipment caused by uneven electric field distribution, we proposed a novel method for enhancing the nonlinear conductive properties of SiC nanowire/epoxy composites through magnetic field-induced orientation in this work. First, magnetic Fe₃O₄ nanoparticles were loaded onto the SiC nanowire surface to impart magnetic field responsiveness. Subsequently, curing under an ex-ternal magnetic field achieved the oriented arrangement of nanowires within the epoxy matrix. Results demonstrated that the oriented composites exhibit exceptionally high nonlinear conductance even at low volume fractions. At a volume fraction of 5% loading, the nonlinear coefficient α reached a maximum of 30.88, with all oriented samples exceeding a α of 15. By adjusting the volume fraction of SiC@Fe₃O₄ filler and the loading amount of Fe₃O₄, the threshold electric field (E_s) strength of the composite material could be effectively tuned. XPS analysis and First-principles calculations confirmed that the built-in electric field and Schottky barrier formed at the SiC-Fe₃O₄ interface due to electron transfer were the dominant factors responsible for the nonlinear conductivity properties. TSDC test further revealed that Fe₃O₄ loading modulated E_s by introducing deep-level traps. This study provides novel fabrication strategies and theoretical foundations for designing high-performance nonlinear conductive insulating materials.

Foamed expanded graphite (EG)/thermoplastic polyurethane elastomer (TPU) composite sheets were prepared using melt blending, supercritical fluid foaming, and other processes. Capacitive pressure sensors were assembled by adopting these foamed sheets as the dielectric layer. Thus, the influence of EG and supercritical fluid on the pressure-sensing performance was studied, and the influence mechanism was revealed. The results showed that EG could effectively increase the permittivity of the EG/TPU composites and the sensitivity of the corresponding sensor, which was related to the interfacial polarization between the introduced EG layers and the TPU matrix. By conducting supercritical fluid foaming on the EG/TPU composites, three-dimensional microcellular structures were effectively constructed, and the foaming process enhanced the deaggregation of the EG aggregates in the composites with higher EG content. The former could effectively increase the thickness variation of the dielectric layer during the compression process and cause a large amount of low-permittivity air to be replaced by high-permittivity EG/TPU solids during compression, thereby effectively increasing the apparent permittivity change of the dielectric layer during the compression process. The latter was favorable for forming the micro-capacitance structure of the EG layer-air-EG layer within the dielectric. The functions of the above two aspects could significantly improve the sensitivity values of the micro-cellular EG/TPU sensors: compared with the 1.5 wt% EG composite, the sensitivity in the medium-pressure region was increased by approximately 71 times after foaming. The test results of other performances and applications of the sensor showed that the capacitive pressure sensor based on the foamed EG/TPU sheets exhibited low resolution (as low as 0.5 N), low pressure detection limit (as low as 1 kPa), and good cyclic stability. It had a good application prospect in movement monitoring for wrist bending, finger grasping and sitting/standing.

The composition of copolymer units plays a crucial role in determining the structure and performance of poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) copolymers. This study employed samples with varying HFP contents to systematically investigate the crystallization behavior of P(VDF-HFP) melts under high-pressure external fields, as well as the evolution of their phase structures and morphologies under different temperature and pressure conditions. The results demonstrated that an increase in the HFP copolymer unit content progressively suppresses the formation of extended chain crystals (ECCs) under high pressure. This suppression can be primarily attributed to the large side group volume of HFP, which thermodynamically and kinetically hinders the growth of the high-pressure hexagonal (h) phase. Consequently, both the ECC content and melting point decreased. Conversely, the introduction of HFP significantly enhanced the generation of the polar β-phase induced by high pressure. As the HFP content increased, the β-phase emerged successively in the form of ECCs and folded chain crystals (FCCs). Under high-pressure external fields, the promoting effect of HFP on β-phase formation is likely due to its steric hindrance, which facilitates the generation of the all-trans (TTTT) conformation and stabilizes the TTTT conformation, induced by high pressure. This stabilization prevents the h-phase, which cannot thicken, from relaxing into α-FCCs during crystallization. During this process, the β-phase exhibits significant lattice expansion, with the (110) interplanar distances approaching those of the α-phase. This suggests that a small number of HFP units were incorporated into the lattice as defects, which reduced the crystalline order. Furthermore, unlike pure PVDF, the incorporation of HFP effectively mitigates the thermal degradation of the material while significantly promoting the formation of the β-phase under high pressure. This characteristic provides substantial advantages for practical applications of the material.

Coil coatings play a pivotal role in safeguarding metal substrates against environmental degradation; however, their durability optimization remains a critical challenge in industrial applications, which are mainly characterized by excessive dependence on empirical methods and intricate interactions among multiple influential factors. Thus, this study aims to address these critical issues. The design of experiments (DOE) methodology was adopted as the core research framework, implemented using Minitab statistical software to ensure rigorous experimental design and data analysis. The key variables investigated included pigment blending (ranging from 0.2 to 0.8 by weight) and the blending ratio of high-durability resins (with weight ratios ranging from 1:1 to 4:1). The color change and gloss retention of coil coating were tested after ultraviolet fluorescent aging test. The effects of pigment loading and the blending ratio of high-durability resins on aging resistance were systematically investigated. Statistical analysis of the DOE data revealed that pigment loading, high-durability resin blending, and their interaction effect were statistically significant (P<0.05). Specifically, moderate pigment loading (0.4) provided optimal color stability, while a blending ratio of 1:1 (weight ratio of general to high-durability resin) synergistically enhanced both color stability and gloss retention. Furthermore, the established model elucidated the regularity of the response between the aforementioned factors and the aging resistance of the coating. The synergistic mechanism between pigment loading and high-durability resin blending was quantified, validating the high efficiency and feasibility of the DOE approach in coil coating formulation development. These findings provide a scientific basis for rational formulation design with tailored performance and reduced development costs.