Journal of Polymer Research最新文献

Phase change materials (PCMs) hold tremendous potential in sustainable energy utilization, with green preparation and efficient application emerging as key research hotspots in this field. However, PCMs face two persistent challenges in practical use: liquid leakage when temperatures exceed the melting point, and the inherently low thermal conductivity of PCMs. Therefore, we prepared a shape-stable SA/PEG/PDA@CNTs (SPC) composite phase change material using bio-based sodium alginate (SA) as the carrier material, polyethylene glycol (PEG) as the phase change component, and polydopamine (PDA)-modified carbon nanotubes (CNTs) as the functional filler. The results indicate that SPC2 possesses a high phase-change energy storage density, with a melting enthalpy of 137.8 J/g. The introduction of PDA-modified CNTs (PDA@CNTs) significantly improved the thermal conductivity of SPC2, increasing its thermal conductivity by 108%. Meanwhile, PDA@CNTs endow SPC2 with photothermal conversion capability, achieving a photothermal conversion efficiency of 88.4%. Therefore, composite phase change materials designed using this method have advantages such as environmental friendliness, low cost, and excellent thermal performance. Furthermore, this material has promising application prospects in fields such as solar energy utilization, industrial waste heat recovery, and thermal management of electronic devices.

This study explores a surface functionalization approach using stearic acid to enhance the performance of polypropylene (PP)-based nanocomposites reinforced with titanium dioxide (TiO₂) nanostructures. Both untreated and stearic acid-treated TiO₂ were incorporated into the PP matrix to systematically investigate their influence on the multifunctional properties of the composites. Comprehensive characterization was carried out to assess the effects of surface treatment on structural, morphological, electrical, and mechanical behaviors. Fourier Transform Infrared (FTIR), and X-ray Diffraction (XRD) analyses confirmed the successful surface modification of TiO₂ and its influence on the crystalline structure of the polymer matrix. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) observations revealed improved nanoparticle dispersion, reduced agglomeration, and enhanced interfacial compatibility in composites containing treated TiO₂. Electrical conductivity measurements showed significant enhancement with increasing TiO₂ content, particularly in treated systems, due to better nanoparticle distribution. Rheological and impact resistance analyses indicated that surface-modified TiO₂ preserved flow properties at low filler content and improved toughness at higher loadings. These results demonstrate that stearic acid-modified TiO₂ can serve as an effective strategy for improving the multifunctionality of PP-based nanocomposites.

Addressing the technological challenges in the automotive industry concerning energy consumption, environmental protection, aging susceptibility, and safety, this study focuses on the lightweighting and UV-resistant modification of polypropylene (PP)-the most widely used and highest-volume polymeric material in automotive plastics. Such design holds critical significance for the green transformation of the automotive industry. The research employs hollow glass beads (HGB) and titanium dioxide (TiO₂) as functional fillers, and successfully develops a novel PP-based composite material through surface grafting modification of HGB using tetrabutyl titanate (TBT). The results indicate that the coupling agent TBT uniformly coated the surface of HGB via chemical bonding, significantly enhancing the interfacial interaction between the filler and the PP matrix, thereby laying the foundation for improved mechanical properties of the material. The self-lubricating effect of TiO₂ effectively reduces intermolecular friction within the system, elevating the MFR of the composite material to 15.43 g/10min, thus significantly improving its processability. After undergoing 100 h of artificial accelerated hygrothermal aging tests, pure PP specimens exhibit obvious cracking and performance degradation, whereas the PP/TBT-HGB/TiO₂ (0.50 wt%) composite material shows no visible surface cracks and maintains excellent mechanical property retention, with a flexural strength of 59.54 MPa, flexural modulus of 1842 MPa, tensile strength of 35.24 MPa, impact strength of 23.58 kJ/m², and a reduced density of 0.886 g/cm³. Compared to traditional PP materials, this composite material not only meets the lightweighting demands of the automotive industry but also enhances weather resistance through the synergistic UV-resistant effect of TiO₂. Its balance of low density and excellent mechanical properties demonstrates significant engineering application advantages in terms of achieving carbon neutrality goals and optimizing overall performance.

Furfural residue (FR), a major lignocellulosic byproduct of industrial furfural production, poses significant environmental challenges due to its disposal via landfilling or incineration. To valorize this underutilized resource, this study presented a sequential acid-periodate approach for extracting dialdehyde-functionalized cellulose nanocrystals (FR-DCNC) from FR. The process initiates with efficient delignification using formic acid/hydrogen peroxide (FA/H₂O₂) pretreatment, yielding purified cellulose (FR-C) with minimal lignin content. Subsequent sulfuric acid hydrolysis liberated cellulose nanocrystals, which were selectively oxidized by sodium periodate to introduce aldehyde functionalities via C2-C3 bond cleavage. Comprehensive characterization revealed that FR-DCNC exhibited high crystallinity (78.6%), a rod-like morphology (diameter = 12.6 nm), and an exceptionally high specific surface area (289 m²/g). FTIR confirmed successful dialdehyde formation while thermogravimetric analysis demonstrated enhanced thermal stability (T_max=221 °C) compared to raw FR. The introduced aldehyde groups (2.6 mmol/g) endow FR-DCNC with high surface reactivity for advanced applications in polymer composites, adsorption, and functional materials. This work establishes a sustainable pathway to transform industrial biowaste into high-value functional nanomaterials, aligning with circular economy principles.

The growing demand for sustainable materials with competitive performance drives research into natural fiber-reinforced composites, a promising alternative to synthetics. Optimizing their properties and expanding applications depend on various factors, such as reinforcement configurations and architectures. Thus, investigating hybrid composites combining jute and flax is strategic for advancing composite materials knowledge and offering solutions to engineering challenges. This study examines the effects of unidirectional (UD) and twill flax reinforcements on the mechanical properties of interlaminated jute/flax hybrids produced by compression molding. Composites were developed with a fixed core of five layers of bidirectional jute fabric, symmetrically covered by one to three external UD or twill flax layers. The influence of flax fabric architecture and number of external layers was assessed by tensile, flexural, and impact tests using a neat jute composite as reference. Results showed that both fabric architecture and number of layers significantly affected mechanical properties. Tensile strength and stiffness increased nearly monotonically with more flax layers. Flexural tests revealed substantial improvements, with a plateau between two and three layers. Under impact, all hybrids outperformed neat jute, with three-layer samples achieving the best results. Overall, hybrids reinforced with UD flax exhibited superior performance across all properties. These findings highlight flax reinforcement’s potential to enhance natural fiber composites for diverse applications.

Polyester, the most widely used synthetic fibre, has been challenging to dye sustainably with its hydrophobic surface and low reactivity, necessitating energy- and resource-intensive high-temperature high-pressure (HTHP) dyeing processes. Enzymatic surface modification with esterase was investigated as a green method to enhance the dyeability of polyester with reactive dyes. Development of -OH and -COOH groups was successfully confirmed by FTIR. A machine learning model, Extreme Gradient Boosting (XGBoost), was trained to predict the concentrations of -OH and -COOH groups (in mmol/g) and the color strength (K/S value) for modified polyester. A data set consists of 351 experimental data points, each experiment repeated 3 times, comprising process parameters (esterase (%), time, temperature, and pH), was used to train and evaluate the model. Strong predictive capability was demonstrated by the model, with R² values exceeding 0.9 for -OH, -COOH, and K/S. Interpretability by SHAP analysis identified enzyme concentration as the most influential factor, followed by pH, time, and temperature. Residual analysis confirmed normally distributed errors and small deviations of approximately 2 mmol/g for more than 90% predictions, affirming the robustness of the model. Improvement in wicking height, absorbency, and reduced contact angle demonstrated enhancement in hydrophilicity, without affecting the tensile strength. Thermal analysis using DSC revealed melting as well as crystallisation behaviour modifications, complementing modifications at the surface level. Overall, this integrated (enzymatic processing and machine learning) approach for a cleaner production strategy reduces energy usage, minimizes environmental discharge, and presents a viable path toward more sustainable, eco-efficient textile dyeing.

Global water scarcity and soil desertification underscore the critical need for efficient, cost-effective water-retentive materials in sustainable agriculture. To address this, graphene oxide (GO), carbon nanotubes (CNT), and rice husk biochar (RBC) were incorporated into an acrylic acid/2-acrylamido-2-methylpropanesulfonic acid/sodium alginate copolymer network, fabricating three carbon-composite superabsorbent polymers (GO-SAP, CNT-SAP, RBC-SAP). Systematic evaluation revealed that carbon materials dispersed uniformly within the polymer matrix via hydrogen bonding and van der Waals forces, with surface oxygen-containing groups significantly enhancing hydrophilicity. XRD and SEM analyses confirmed amorphous porous structures, with GO-SAP and RBC-SAP exhibiting superior pore distribution. Maximum swelling ratios occurred at loadings of 0.08 g (GO), 0.12 g (CNT), and 0.12 g (RBC). At equivalent loadings, GO-SAP demonstrated the highest absorption capacity, attributable to GO’s strong hydrophilicity, 2D lamellar structure, and exceptional dispersibility. All composites maintained high swelling ratios between pH 5–10 and 20–50 °C but showed sensitivity to multivalent ions. Swelling kinetics followed a pseudo-second-order model (R² > 0.99), indicating chemically controlled absorption governed by hydrophilic groups. Remarkably, the composites retained water for > 4.5 h at 50 °C and preserved > 97% water retention after centrifugation (12,000 rpm). Cyclic stability exceeded 80% of initial swelling capacity after 6 absorption-desorption cycles. This work provides a robust foundation for developing high-performance, sustainable superabsorbents.

A novel gradient copolymer, poly(norbornadiene-grad-cyclohexadiene), was synthesized via ring-opening metathesis polymerization (ROMP) of norbornadiene (NBD) and vinyl-addition of cyclohexadiene (CHD) mechanism using Grubbs’ third-generation catalyst (G3). To overcome the intrinsic brittleness and limited thermal performance of cyclic olefin copolymers, the material was further modified through catalytic hydrogenation using a palladium supported on porous nickel decorated with carbon nanotubes (Pd@PN-CNT). The post-polymerization (catalytic hydrogenation) significantly enhanced the thermomechanical properties: the glass transition temperature increased from 127 ℃ to 139 ℃, and the degradation temperature rose from 438 ℃ to 519 ℃. Mechanical testing revealed improvements in tensile strength (from 14.58 MPa to 28.93 MPa), elongation at break (from 16.44% to 32.34%), and elastic modulus (from 28.61 MPa to 39.87 MPa). These improvements are attributed to the saturation of unsaturated bonds, reduction in chain defects, and enhanced phase separation. The high hydrogenation efficiency of the Pd@PN-CNT catalyst also demonstrated excellent reusability. This work presents a viable route for tailoring the thermal and mechanical performance of gradient copolymers, positioning hydrogenated poly(NBD-grad-CHD) as a promising candidate for advanced applications in elastomers and high-performance engineering materials.

In the present study, we investigated the segregation behavior of a plasticizer, i.e., dibutyl phthalate (DBP) in a polymer, i.e., polystyrene, subjected to a temperature gradient. We confirmed homogeneous distribution without phase separation when the DBP content was ≤ 15%. A sample film containing 10% DBP was annealed in a compression-molding machine, in which the top and bottom plates were held 3 mm apart at 200 and 120 °C, respectively. After exposure to the temperature gradient, a DBP gradient distribution was confirmed in the thickness direction: there was a high DBP content at the high-temperature side and a low DBP content at the low-temperature side. The result indicates that a plasticized polymer adopts a plasticizer concentration gradient, i.e., a graded structure, when subjected to a temperature gradient.

Emulsified oil has dynamic stability, and its harmless treatment has become a challenging problem worldwide. Membrane filtration technology has garnered significant attention in the field of oil-water separation due to its low cost, high efficiency, and environmental friendliness. In this study, NH₂-CAU-1 was incorporated into a polyphenylsulfone (PPSU) matrix to fabricate superhydrophilic and antifouling mixed matrix membranes (MMMs) via the phase inversion method, which were subsequently used for the separation of several oil-in-water emulsions. By adjusting the NH₂-CAU-1 loading capacity, the mechanical properties, wettability, separation performance, and antifouling properties of the MMMs were optimized. The results indicated that when the NH₂-CAU-1 loading is 0.1 wt%, the MMMs exhibited superhydrophilicity (water contact angle is 4.2°) and underwater superoleophobicity (underwater oil contact angle is 153.4°), achieving a separation efficiency of over 99.55% for various oil-in-water emulsions, with an irreversible fouling rate of only 2.66%.