Zhidong Xia

With the progressive replacement of early-21st-century wind-power equipment, end-of-life wind-turbine blades made of carbon-fiber-reinforced polymer (CFRP) present a significant disposal challenge due to their poor natural degradability, making pyrolysis the mainstream treatment route. To simplify processing and minimize fiber damage, this study investigates direct pyrolysis of structural-scale CFRP specimens (50 × 10 × 20 mm) in a fixed-bed reactor. The overall mass loss stabilized at 31%, and the lamination-direction expansion reached 30–40%, yielding a decomposition extent comparable to millimeter-scale samples but with superior fiber integrity. A three-step “pyrolysis–oxidation–vacuum annealing” process was subsequently developed, producing well-dispersed carbon fibers whose electrical conductivity increased from 792 ± 16.4 S cm⁻¹ after oxidation to 885 ± 15.8 S cm⁻¹, while tensile strength improved from 1206 ± 193.7 MPa to 1670 ± 49.5 MPa. These results demonstrate the feasibility and advantages of efficient pyrolysis at the component scale and provide a robust process framework for maintaining carbon-fiber properties and enabling high-value recycling.

The development of electrochemical sensors (ECSs) with enhanced sensitivity has emerged as a focal point in contemporary sensor technology research due to the important biochemical roles of hydrogen peroxide (H ₂ O ₂ ) in the industrial and biological fields. In this paper, a high‐performance ECS based on laser‐irradiated carbon nanotube (LICNT) electrode as the working electrode (ECS‐LICNT) for sensitive detection of H ₂ O ₂ is designed and fabricated to achieve long‐term monitoring of trace concentrations of H ₂ O ₂ . The thickness and surface microcluster structure of LICNT electrodes were optimized by precise control of laser energy density and CNT suspension dose. The ECS‐LICNT, designed with a dual mechanism combining surface laser‐induced oxidation to increase active point density and ordered microcluster structure to enhance effective active area, possesses a high sensitivity of 475 μA·mM ⁻¹ ·cm ⁻² in a wide range (10–9000 μM), surpassing most reported pure carbon‐based sensors. In addition, the sensor exhibits excellent stability (current decay n = 7), maintaining 95.8% of its initial response even after 28 days of storage. The ECS demonstrates sufficient sensitivity to accurately determine H ₂ O ₂ concentration in the presence of interfering substances such as ascorbic acid (AA), glucose (Glu), and uric acid (UA). It can be foreseen that this sensor provides a novel strategy for designing efficient ECSs and has broad application prospects in the fields of biomedicine and food safety detection.

The monitoring of biophysical signal parameters, including respiration, heartbeat, and fetal movement (FM), is essential for disease prevention and diagnosis. In this paper, to achieve long-term monitoring of biophysical signal, a high-sensitivity flexible capacitive sensor (FCS) based on carbon nanotubes (CNTs)-filled dielectric composite (DC) with multi-layer pore architecture is designed and fabricated, where the exquisite structure of DC is constructed based upon the characteristics of low surface vapor pressure of 1,2-propanediol (1,2-PG) and 3D printing technology (3D-p), while the electrode material is consisted of conductive silicone rubber (CSR) filled with silver-coated glass fiber. The fabricated sensor exhibits a low detection limit (12 Pa), a high sensitivity in a wide range (2.3 kPa-1 to pressure load less than 1.5 kPa, and 0.73 kPa-1 to the pressure between 1.5 and 12.5 kPa), fast response time (0.3 s), and excellent stability (> 104 cycles). Numerical simulation and mechanism analysis indicates that the varying dielectric constant of CNTs-filled DC with pressure is the key to high sensitivity for the sensor, and the pore architecture enlarges the load response range. The FCS is sensitive enough to capture simultaneously multiple signals of subtle movements, including breathing, heartbeat, and skin touching in the abdomen, which could be distinguished with the help of post digital analysis. It is foreseeable that the sensor has a broadly prospective application in the field of biophysical signal monitoring in home or medical electronic healthcare.

The degradation of rubber performance in service environments is closely associated with the blooming behavior of additives in the rubber. This study investigates surface precipitates and changes in tensile properties of nitrile butadiene rubber (NBR) after storage at 85°C in air. The morphology, elemental composition, phase composition, and functional groups of the precipitates were analyzed by scanning electron microscopy, energy dispersion spectroscopy, X‐ray diffraction, and fourier transform infrared spectroscopy. Based on the morphology of internal rubber particles and precipitates and variations in the Zn/C mass ratio (ER_Zn), the reaction between zinc oxide and stearic acid in rubber under long‐term thermal environment was determined. Four stages of blooming for the mixture of zinc oxide and zinc stearate were inferred, and the impact of the blooming on the degradation of tensile properties of NBR was established. A dramatic decrease in the elongation at break (δ_k) of NBR was correlated with the blooming of zinc stearate and its correspondingly weakened plasticizing effect.Highlights: The core‐shell structured mixture of ZnO and Zn(St)₂ bloomed onto the surface of nitrile butadiene rubber. The ratio of mass percentages of Zn to C evaluated the blooming process of additives. The migration and blooming process of precipitates were divided into four stages. The decrease in elongation of the rubber was attributed to the blooming of Zn(St)₂.

The emission of chlorinated pollutants is one of the main problems when recovering copper (Cu) via pyrolysis from waste enameled wires. This is mainly attributed to other wastes which possess high poly(vinyl chloride) content, such as electrical wires and cables, which are often recycled together with enameled copper wires. In this research, to control the chlorinated pollutants, copper(II) oxide (CuO) was chosen and demonstrated to be an efficient dechlorinating agent, and CuO did not introduce any impurities that influence the quality of the recovered Cu. The pyrolysis and co-pyrolysis of polyester enameled wires, PVC, and CuO were investigated, and special attention was paid to chlorinated compounds in released pyrolytic products. In particular, the co-pyrolysis of this ternary mixture was studied for the first time, and some new pyrolysis behaviors were discovered. For example, the results of Py-GC/MS analyses showed that the addition of CuO removed about 75% of the chloro-organic products, the main types of which were chloroaromatic compounds rather than the more toxic chloroesters. Moreover, pyrolysis gases were collected and characterized via ion chromatography, and the results showed that the chlorine content in the pyrolysis gases decreased by about 71%. TG analysis indicated that CuO only minimally affected the pyrolysis of polyester paint. However, through the chlorine fixation effect, CuO influenced the dechlorination and dehydrochlorination of PVC, as well as secondary reactions between HCl and pyrolysis products of polyester paint, therefore changing the products and behaviors of co-pyrolysis. Mechanism of reducing chlorine-containing pollutants and reaction mechanism of forming typical pyrolysis products closely correlated to the effects of CuO were also proposed, providing theoretical guidance for the recycling of waste enameled wires.

Flexible strain sensors have been improved in sensing performance with the assistance of materials design, novel manufacturing, and microstructure fabrication. In this study, graphene was efficiently dispersed in ethanol and then re-dispersed into silicon rubber (SR) matrix, functioning as a flexible strain resistance sensor (FSRS) with functional macrostructure and modified microstructure to further improve the sensitivity. A stable dispersion of graphene was obtained in an ultrasound-aided ball milling process, where absolute ethanol was selected as the solvent and sodium dodecyl sulfonate as the surfactant. Graphene-filled conductive SR was embedded in the polydimethylsiloxane matrix as a conductive sensing layer, and the high sensing performance (GF = 25 ± 2) was achieved using a spiral printed. Micropores with an optimized interspacing of 10 mm were further introduced into the spiral CSM, and the results presented a significant improved sensitivity (GF = 51 ± 4) of the fabricated FSRS under a working strain (20%–30%) and cyclic test (>10 ⁴ cycles). The FRSR was sensitive enough to monitor various movements of single and multi-joints of human body and identify the rhythm of music sound, which exhibited its potential application as a wearable flexible sensor.

Traditional metallic interdigital electrodes are rigid and undeformable, flexible interdigital capacitors are therefore appealing as strain sensors. In this study, interdigital capacitors were parametrically designed by 3D printing and encapsulated by spraying process. The interdigital circuits of the structure were printed with conductive silicone rubber (CSR) filled with silver-coated glass fiber and carbon fiber (CF), and the circuits were encapsulated with polydimethylsiloxane (PDMS). Herein, the interdigital-flexible structures were parametrically designed and firstly served as capacitive sensor, namely flexible interdigital capacitive sensors (FICS). The spaces between interdigital electrodes (IEs), are extremely sensitive to strain, therefore provide the capacitors with excellent electromechanical behaviors. The optimized FICS benefited for a wide working range of strain (0~45%), high sensitivity (gauge factor, GF=2.7) to a tiny strain of 0.3 %, stable working duration at different stretching speeds (18 mm/min, 36 mm/min and 72 mm/min), prolonged service life (>800 cycles), as well as excellent capability to detect human movement (bulging, grasping and bending). Response mechanism of the FICS was modelled based upon its microstructure evolution, including the distances between IEs and the fillers migration. The printed FICS with optimized structure provide a comprehensive thought in the design of electronics, further would inspire the branch of 3d printed electronics.

3D printing electronics provides great potential to build structural objects with multiple functionalities, with the assistance of shape design and the shear force on the filler orientation. In the study, nano–microanisotropic sensors with oriented fillers assure its linear sensitive properties, where the sensors are 3D‐printed based upon the carbon fiber (CF)‐ and multiwalled carbon nanotube (MCNT)‐filled polydimethylsiloxane (PDMS). The synergistic effect of CF and MCNT modifies the printability, mechanical properties, and sensitivity of printed sensors. The introduction of anticatalyst and catalyst guarantee the printable mixtures with a stable printability in a long term (>15 days). Assisted by the shear flow, the fillers own the orientation ration of 78.53%, which further contribute to the linear sensing behaviors under the tensile strain of 0–20% and compressive stress of 0–20 kPa. Frequency‐domain signals and visual demonstration on the cyclic stretch test reveal that the double peak is originated from the hysteresis of the strain to applied stress. Anisotropic electromechanical behaviors of the resistors will inspire to quantitatively analyze multidimensional strains in practical applications. The fingerprint inspired resistors with multiple sensing signals further demonstrate the convenience of the printing process on the design of wearable electronics.