Journal of Polymer Research最新文献

The use of polymeric materials in orthopedics is becoming increasingly important. Polylactide (PLA) has the necessary set of properties for use in this area. In particular, the ability to degrade in biological fluids allows avoiding repeated surgery to remove a PLA implants. The addition of various fillers can affect the change in mechanical, structural and biological characteristics. In this paper, the effect of the biodegradation process on PLA-based composites with the addition of HA and SiO₂ particles was studied. The biodegradation process in this study was carried out for 4 weeks in two environments: phosphate buffered saline (PBS) and fetal bovine serum (FBS). The mechanical characteristics of the materials were reduced after biodegradation, while the degradation rate increased with an increase in the concentration of the additive. The study of the material biocompatibility showed that their extracts did not induce cytotoxicity. The PLA-based composites more actively stimulated the adhesion of cells with osteogenic potential after incubation in FBS. In combination with good biocompatibility, it indicates the prospects of using implants for the reparation of bone defects.

Cross-linked polyethylene (XLPE) is commonly used as an insulation material for high-voltage direct current (HVDC) cables due to its excellent dielectric strength, low dielectric loss, superior insulating properties, as well as its good thermal stability and mechanical performance. This study introduces benzophenone-based voltage stabilizers—3,3’,4,4’-Benzophenonetetracarboxylic dianhydride (BTDA), 4,4’-Diaminobenzophenone (DABP), and 2-hydroxy-4-prop-2-enyloxybenzophenone (ALOH)—which are incorporated into XLPE to enhance its electrical performance. Experimental results show that XLPE incorporated with DABP exhibited the most significant improvement, achieving a 16.5% increase in DC breakdown strength at 30 ℃ and nearly one order of magnitude reduction in conductivity at 70 ℃ and 40 kV·mm^− 1 compared with pure XLPE. Space charge accumulation was also effectively suppressed. These stabilizers mitigate space charge accumulation, enhance conductivity, and maintain stable breakdown strength, especially under elevated temperature conditions, thereby improving the decline in electrical performance of conventional materials in high-temperature environments. Density functional theory (DFT) analysis suggested that the synergistic interaction between electron-withdrawing groups (EWGs) and electron-donating groups (EDGs) in DABP facilitates balanced charge trapping and transport. These results demonstrate that DABP is a promising molecular stabilizer for improving the dielectric reliability of XLPE insulation in HVDC applications.

A magnolol-based phosphonate flame retardant (DPDO) was synthesized using magnolol and phenylphosphonyl dichloride, and DPDO was subsequently grafted onto fullerene (C₆₀) through the Friedel-Crafts alkylation reaction. The successful synthesis of C₆₀-DPDO was confirmed via nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR). Flame-retardant polypropylene (PP/IFR) was prepared by the melt blending method, and the thermal stability, flame-retardant performance and combustion behavior were evaluated using thermogravimetric analysis (TGA), limiting oxygen index (LOI), vertical burning and cone calorimetry. The results indicated that C₆₀ significantly impaired the thermal stability and flame retardancy of PP/IFR, whereas C₆₀-DPDO notably enhanced both properties. With the incorporation of 0.5% C₆₀-DPDO, PP/IFR achieved a UL94 V-0 rating, with an LOI value reaching 34.5%. Furthermore, C₆₀-DPDO effectively inhibited and delayed the combustion process of PP/IFR, significantly reducing heat release and smoke generation, particularly delaying the peak heat release rate by over 1,000 s. To investigate the flame-retardant mechanisms in both the condensed and gaseous phases, scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), Raman spectroscopy, thermogravimetric-infrared spectrometry (TG-IR) and pyrolysis gas chromatography-mass spectrometry (Py-GC/MS) were employed. The findings revealed that in PP/IFR, the radical addition reaction of C₆₀ primarily disrupted the intumescent flame-retardant action of IFR, while that of C₆₀-DPDO mainly suppressed the pyrolysis of PP.

This study visualized and recorded the foaming process of a polypropylene/azodicarbonamide (PP/AC) system using in-situ observation equipment. The obtained data were fitted and analyzed using nucleation and growth models. By combining real-time pressure measurements from sensors integrated into the visualization mold, the influence of the cavity pressure environment on cell nucleation and growth was systematically investigated. The results demonstrate that adjusting the cavity volume and shot size can effectively modulate the internal cavity pressure. Building a higher cavity pressure is beneficial for improving the thermodynamic stability of gas/polymer systems. Meanwhile, the pressure drop generated during the core-back process induces extensive cell nucleation within a short period. The final foaming quality is simultaneously affected by the cavity pressure and pressure drop rate. Additional experiments with increased foaming agent content confirmed that foam quality continues to improve with higher initial cavity pressure.

Polymer additives play an important role in retaining, enhancing, and modifying the properties of polymers for various end-use applications such as construction, automotive, electronics, pharmaceuticals, food, and medical industries. Polyolefin-based products are particularly significant in the packaging industry due to their low cost and large-scale availability in the market. The demand for polyolefin products in the form of bottles, jars, drums, cans and other types of containers has increased exponentially due to their sustainability, high recyclability, light weight, chemical resistance, barrier properties, and lower carbon footprint compared to other packaging materials. Additives such as UV stabilizers, antioxidants, processing aids and pigments are required for the processing and long-term stability of polyolefin-based products. Simultaneously, it is essential that these chemical additives be either eco-friendly or have reduced hazardous effects after migration into the environment. This review presents the most recent advances in research and development of functional additives for polyolefin materials. Emphasis is placed on the basic understanding of various types of antioxidant stabilizers and their reaction mechanisms involved in polymer stabilization. Different formulations of stabilizers, antioxidants, and processing aids are discussed, including their concentrations and specific applications. Additionally, the hazardous effects of chemicals present in additives and their migration into the environment are addressed. Finally, the use of bio-based functional additives and their formulations in polyolefin materials is encouraged and discussed in light of environmental, health, regulatory, and economic issues.

Bamboo fiber filled polymer composite (BPC) characteristically display elevated mechanical strength, low density, degradability, corrosion inhibition, electromagnetic interference as well as inferior heat dissipation features especially with nanostructures including graphene (GRN) and derivatives, carbon nanotubes (CNTs) including multiwall and single-wall CNTs. Bamboo is a natural fiber depicted by rapid development, brief duration of cultivation, elevated strength and satisfactory toughness, and amongst strongest natural fibers globally. Due to their inherent environmental compliancy and inexpensiveness, natural fiber composites are garnering great attraction for multifacet uses. With inherent display of one directional specific strength and specific modulus greater than glass fiber, BPC exhibit applicability prospects in packaging, aerospace, wind power, aviation, and construction, automotive, biomedical and so on. Nanotechnological emergence has promoted the addition of organic or inorganic nanostructures such as GRN, montmorillonites, along with graphene nanoplateletes, and so on, within natural fiber reinforced polymeric composites and nanocomposites thereby enhancing their features hence, increasing their versatility of applications. Hence, this paper elucidates emerging advances in bamboo fiber filled polymeric composites.

In this work, a series of 3D-printed orthopedic footpad composite samples were fabricated using thermoplastic polyurethane (TPU) and polylactic acid (PLA) as supporting structures, infused with biopolymeric fillers including polycaprolactone (PCL), sodium alginate, and natural mastic resin. Twelve different formulations were prepared and systematically assessed through structural (FTIR, SEM), physicochemical (wettability, absorbency), biological (antifungal and antibacterial activity and cytotoxicity), and mechanical (tensile and compressive strength) tests to estimate their performance under simulated physiological conditions. Among all samples, TPU-based composite filled with 90% PCL and 10% sodium alginate (TPA) exhibited superior multi-functional performance. FTIR analysis confirmed successful physical compatibility between TPU and PLA with hydrophilic additives without chemical bonding. FESEM images revealed a well-integrated, homogeneous microstructure with minimized voids and enhanced surface coherence for both groups. Wettability measurements showed lowest contact angle (41.06°) presented a significant increase in hydrophilicity for PCL-based composites e.g., TPA and PPM (PLA filled with 90% PCL + 10% mastic), resulting in high hydrophilicity, which correlated with its maximum sweat absorbency up to 63.58% in TPA and 56.50% in PPM. Furthermore, TPA demonstrated effective antifungal activity against C. albicans (13 mm inhibition zone) and C. parapsilosis (10 mm). In terms of mechanical behavior, PLA-based samples had higher tensile strength (up to 28.79 MPa for sample P) had higher compressive strength (up to 40.71 MPa), while TPU-based samples presented superior elasticity (elongation > 250%) and impact-absorbing capabilities. Statistical analysis confirmed highly significant differences (p < 0.01) among all formulations in terms of wettability, absorbency, tensile strength, compressive strength, and cell viability. Cytotoxicity predictions revealed that PCL/alginate-rich composites (TPA, PA, PPA) achieved the highest viability (≈ 88–90%), whereas resin-rich samples (TM, PM) fell near the lower viability range due to bioactive compound release. Overall, among all formulations, TPA and PPA demonstrated the most balanced and optimal combination of structural integrity, hydrophilicity, mechanical robustness, antimicrobial activity, and cytocompatibility, making them the strongest candidates for next-generation biomedical and orthopedic footpads.

Recently, energy and environmental issues have become widespread concerns in human sustainable development. In the present research work, a novel bifunctional material ethylenediamine tetra(methylene phosphonic acid)-modified alginate-based polymer composite EDTMPA-F/A has been successfully developed, which has been utilized both in the biodiesel catalytic synthesis process of free fatty acid (FFA) oleic acid with short-chain alcohol ethanol and heavy metal ions removal from aqueous solutions. EDTMPA-F/A has displayed excellent catalytic performance for biodiesel synthesis, and the corresponding reaction parameters such as molar ratio of alcohol to acid, catalytic amount and reaction temperature have been optimized by response surface methodology (RSM), and the highest conversion ratio (89.0 ± 0.6%) could be achieved at the optimum conditions with 10.76 wt% of catalyst amount and 6.63: 1 of ethanol to oleic acid molar ratio at 81.27 °C. Furthermore, a systematic kinetic study on the esterification reaction was conducted. Meanwhile, EDTMPA-F/A has also exhibited efficient adsorption properties for heavy metal ions, especially for lead ions. The adsorption kinetics and the adsorption isotherms of EDTMPA-F/A for lead ions at different temperatures have been investigated, and the maximum adsorption capacity of EDTMPA-F/A for lead ions could reach 735.29 mg/g at 15 °C. Therefore, it is concluded that the extraordinary features of EDTMPA-F/A for both biodiesel catalytic synthesis and lead ions removal can effectively achieve the highly efficient integration of the functional material and ensure its applicability and feasibility in the industrial scale.

Polyisocyanurate (PIR) foams, which are a special type of polyurethane foam, are mainly used in various industries and for building insulation. However, the flammability of these foams has always been a concern. For this purpose, flame-retardant (FR) additives have been used and investigated in recent research in the formulation of these foams. However, many of these FR additives are not environmentally friendly and do not maintain mechanical strength. On the other hand, petroleum-based polyols are often used in the formulation of these foams, which also pose environmental risks. In this study, soybean oil (SBO) polyol was synthesized using transamidation method. Also, aluminum hydroxide nanoparticles (ATH NPs) additive was produced using mechanical crushing method. PIR foams containing 100% SBO-based polyol and ATH NPs as a halogen-free FR were produced. The properties of SBO-PIR foams containing different percentages of ATH NPs (0, 5, 10, and 20%) were investigated. The effect of ATH NPs on the properties of SBO-based PIR foams including physical properties, thermal stability, morphology, mechanical stability, and flammability was investigated by TGA-DTG, XRD, FT-IR, SEM, tensile strength test, compressive strength test, and open flame test. The findings showed that the addition of ATH NPs significantly improves the thermal and mechanical properties of SBO-based PIR foam.

As a sustainable energy source, solar power has emerged as a key focus in renewable energy research. Nevertheless, its practical implementation faces substantial challenges due to inherent spatiotemporal intermittency. This investigation presents an innovative approach to overcome these limitations through advanced phase change material (PCM) engineering. This work developed hierarchically structured composite PCMs via scalable injection molding technology, integrating high-density polyethylene (HDPE), polyketone (PK), and functional graphite additives. The engineered materials demonstrate an elevated phase transition temperature (Tm = 129.1 °C, ΔH = 101.2 J g⁻¹), making them particularly suitable for mid-temperature solar energy conversion. A breakthrough alternating layered encapsulation architecture enables scalable manufacturing while preventing leakage; 95% dimensional retention is achieved after 100 melt–freeze cycles with < 5.1% latent-heat loss. The synergistic incorporation of 4.5 wt % graphite nanofillers enhances thermal conductivity by 36% (from 0.50 to 0.68 W m⁻¹ K⁻¹), enabling a photothermal conversion efficiency of 23.4% under 250 mW cm⁻² (AM 1.5). These multifunctional composites demonstrate significant potential for next-generation thermal energy management systems, particularly in addressing critical energy storage challenges in solar applications.