Journal of Applied Polymer Science最新文献

Ultra-high molecular weight polyethylene (UHMWPE) has long been used as a bearing component in joint replacement devices, particularly in total hip arthroplasty (THA) and total knee arthroplasty (TKA). These implants are conventionally manufactured using the machining route, and an alternative approaches to produce net-shaped UHMWPE implants has been explored to a limited extent. In this context, its high melt viscosity poses significant challenges in molding complex and thicker components, with uncompromised mechanical strength and ductility. To address both these aspects, a new processing strategy has been presented here, where a tailored amount of short-chain polyethylene grafted maleic anhydride (mPE) is introduced into UHMWPE via the melt compounding technique to enhance moldability. We optimized the injection molding parameters—including melt temperature, mold temperature, injection pressure, and injection time—within a narrow window to achieve a UHMWPE blend with enhanced mechanical properties. When compared to pristine UHMWPE 4% mPE blend exhibited a better melt flow index from 6.2 to 8.2 g/10 min and enhanced ultimate tensile strength (27.5 to 31.4 MPa) and elongation at break (46.4% to 77.7%). Additionally, the crystallinity of the mPE blends decreased to 51%, facilitating better flow characteristics, as indicated by a reduction in complex viscosity from 18.83 to 12.30 kPa·s. Using the optimised molding parameters, we successfully molded acetabular liners of commercial design with acceptable dimensional tolerances (shrinkage: 2.1%–2.4%; ovality: 0.06–0.09 mm) and without detectable internal defects, as analysed using micro-computed tomography (micro-CT). The present work highlights the potential of mPE blends in injection molding for producing high-performance orthopedic implants, addressing a critical gap in scalable manufacturing processes for components of varying sizes and shapes in biomedical applications.

Conventional gas separation membranes are mostly aimed at improving the permeability and selectivity of membranes. However, the actual application environment is complex and changeable, and the failure of the material is a common problem in the use process. Fluorinated polyurethane acrylate was synthesized via the fluorinated unit alcohol end-capping approach to enhance the antioxidant capacity of gas separation membranes. The fluorine element is used as an important part of the membrane structure, and then the antioxidant capacity of the membrane is enhanced. Specifically, hexamethylene diisocyanate isocyanurate (HDI) trimer and 1H, 1H, 2H, 2H-Tridecafluorooctanol (TFOA) were precisely metered and underwent an addition reaction. Subsequently, two molecules of the resulting addition products were connected to a molecule of 1,6-hexanediol (HDO). This was followed by a nucleophilic addition reaction between hydroxyethyl methacrylate and the fluorine-rich molecular formula, yielding fluorinated polyurethane acrylate (FPUA). To fabricate the gas separation membrane, photoinitiators were incorporated into the FPUA, followed by curing under UV irradiation. Under optimized conditions, the membrane exhibited exceptional performance in CO₂/SF₆ separation, achieving a gas selectivity of 126.11. The presence of abundant carbon, fluorine, and oxygen atoms in the separation layer significantly bolstered its antioxidant properties. After immersion in a 1 g/L NaClO solution for 7 days, the membrane exhibited minimal corrosion loss of only 1.5% ± 1.3%, and the water contact angle decreased by just 1.8°. This robust membrane material offers promise for the separation of mixed gases containing oxidizing components.

Hydrogen sulfide (H₂S), as a toxic gas, is one of the occupational hazards to workers' health. Traditional H₂S sensors often suffer from external circuits, measurement systems, liquid-phase reactions, or high detection limits. Herein, a colorimetric sensor for H₂S detection was developed by incorporating colorimetric dye [lead acetate, Pb(OAc)₂] into polyacrylamide (PAM)/polyvinyl alcohol (PVA) hydrogel. Benefitting from the interpenetrating polymer network, non-covalent interactions such as hydrogen bonds and dense internal structure, the hydrogel exhibited excellent adhesion to different substances (adhesion strength up to 14.11 kPa) and mechanical properties (tensile strength up to 116.92 kPa, elongation rate up to 576%). Furthermore, due to the liquid-phase reaction system and excellent [Pb(OAc)₂] loading capacity provided by the hydrogel, the prepared sensors exhibited excellent sensing performance response time, sensitivity, and simplicity. The theoretical detection limit of the sensor was 0.69 ppm, and the minimum exposure time required for detection was 14 s. The colorimetric effect of the hydrogels was positively correlated with the addition of Pb(OAc)₂ and the extension of time. The results showed that the color change of PAM/PVA/Pb(OAc)₂ hydrogel can be visible to the naked eye even if the concentration of H₂S is only 1 ppm. It is expected that this hands-free, arbitrarily adhesive, stretchable hydrogel colorimetric sensor strategy for visual detection of H₂S will extend toxic gas alarm systems to a new level.

Here, we report the findings of the development and characterization of a mechanically robust hydrophobic hexagonal boron nitride (h-BN)-polyaniline (PANI)-based polydimethylsiloxane (PDMS) coating for mild steel with active corrosion protection. PANI was in situ synthesized on the surface of h-BN sheets, resolving the inherent stacking nature of h-BN and agglomeration of PANI, and then incorporated into a PDMS coating. The wettability studies revealed that adding h-BN/PANI pigments enhanced the hydrophobicity of the PDMS coating. The impedance modulus (|Z| at 0.01 Hz) of the PDMS coating containing h-BN/PANI was approximately 10⁹ Ω·cm² after 35 days of immersion in a 3.5 wt.% NaCl solution, demonstrating excellent corrosion protection. Further, the results from scratch tests and salt spray tests revealed the active corrosion protection properties of the h-BN/PANI/PDMS coating. The scratch and pull-off adhesion tests confirmed the excellent adhesion of the h-BN/PANI/PDMS coating, and the Taber abrasion test revealed that adding h-BN enhances the wear resistance of the PDMS coating. Antibacterial studies against Gram-negative Escherichia coli bacteria revealed PANI-mediated antibacterial activity, signifying the potential of PANI-incorporated coatings in preventing bacterial-induced corrosion. This work will provide a new perspective on preparing a one-layer siloxane coating with durable anti-corrosion, hydrophobic, and antibacterial properties.

A novel bio-based and biodegradable plastic based on poly(lactic acid) (PLA) and corn starch (CS) was developed as a single-use rigid packaging material. Chitosan (Q) and eucalyptus essential oil (EEO) were incorporated as antimicrobial and antioxidant agents. The effects of these additives were evaluated using a three-factor, two-level factorial design, assessing the melt flow index (MFI) and tensile properties. The optimized formulation, containing 5 wt% of EEO and 3 wt% of Q, increased the thermal stability of CS due to the PLA matrix with two degradation steps: 145°C and 318°C. It also demonstrated low water interaction, with a solubility of approximately 0.6% and a moisture content of 5%, attributed to the absence of plasticizers. Additionally, the material achieved nearly 70% antioxidant activity through the synergistic effect of EEO and Q. Successful thermoforming trials confirmed the processability of the optimized formulation. Comparative analysis with polypropylene revealed that the bio-based material exhibited higher tensile strength while offering the critical advantage of biodegradability. These findings highlight the potential of this active, thermoformable bio-based material as a sustainable alternative to conventional non-biodegradable plastics.