Journal of Polymer Research最新文献

The incorporation of β nucleating agents has been demonstrated to improve the toughness of isotactic polypropylene (iPP), but the underlying mechanism remains ambiguous. This study presents a comprehensive investigation on the toughening mechanism in β nucleated iPP through systematic analysis of both macro-properties and micro-structures. The results show that with the addition of 0.1 wt%, three distinct β nucleating agents, BNA-01, zinc adipate (ZnAA) and zinc phthalate (ZnPA), significantly enhances the impact strength of iPP from 3.6 kJ/m² to 11.7 kJ/m², 6.1 kJ/m², and 8.7 kJ/m², respectively. To elucidate the toughening mechanism, the relative content of β form iPP (k_β) and crystallinity of nucleated iPP were characterized using wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). The results reveal a strong correlation between the β form iPP content and toughness, with higher β form iPP content leading to enhanced toughness. However, the results also indicate that when the content of β form iPP is the same, the toughness of nucleated iPP also differs. To address it, the distribution of β form iPP and spherulite size were examined using polarized optical microscopy (POM). The results indicate that, as the content of β form iPP increases, a continuous distribution of β form iPP will be formed, which can significantly improve the toughness of nucleated iPP. Moreover, under the condition of both continuous distributions, smaller spherulite size contributes to a larger fracture surface, consequently demanding more energy for fracture propagation and ultimately enhancing the toughness. Scanning electron microscopy (SEM) was applied to observe the fracture sections of samples to confirm the toughening mechanism. This study provides new insights into the role of β form iPP content, distribution and spherulite size in the toughening of nucleated iPP, offering a deeper understanding of its structure-property relationships.

A temperature and pH-sensitive biodegradable cationic amphiphilic copolymer, poly [2-hydroxyethyl methacrylate-caprolactone-dimethylamine ethyl methacrylate quaternary ammonium alkyl halide] [P(HEMA-PCL-MADQUAT)], was synthesized via ring-opening polymerization (ROP) and free radical polymerization methods. Structure confirmation was obtained by FT-IR and ¹H-NMR spectroscopy. Nano-micelles derived from the copolymer were characterized by TEM (transmission electron microscopy), DLS (dynamic light scattering), zeta potential, and CMC (critical micelle concentration) analysis, revealing a uniform morphology with a surface charge of − 12.4 mV, an average diameter of 280 nm, and a CMC of 0.01 g/L. The micelles efficiently encapsulated methotrexate and ciprofloxacin, with loading efficiencies of 67.1% and 71.4%, respectively. MTT assays in MCF-7 cell lines demonstrated favorable biocompatibility and CIP@MTX micelles showed lower IC₅₀ than free CIP@MTX in MCF-7 cells (1.5 vs. 5.3 µg·mL⁻¹). These findings highlight P(HEMA-PCL-MADQUAT) micelles as a promising platform for breast cancer therapy, combining effective drug delivery with reduced side effects.

Epoxy resin is a class of thermosetting polymer widely used in high performance protective coating due to its excellent physical and chemical properties. However, its inherent brittleness, along with difficulties in self-healing and recycling, limits its application. In this study, an epoxy resin coating was modified by the combination of Diels-Alder (DA) dynamic reversible bond and soft polyurethane segment. The DA bonds endowed the coating with the ability to repair damage and to be reprocessed, while the polyurethane chain segments, introduced through the DA reaction, can effectively enhance the toughness of the epoxy resin. The chemical structure and properties of the materials were characterized by FTIR, DSC, TGA and universal testing machine. The results showed that due to the presence of soft polyurethane segment, improve the corrosion resistance and wear resistance of coating. Additionally, the Diels-Alder bond endowed the material with excellent thermal self-healing and recycling properties. Therefore, this modified epoxy coating shows great potential in extending service life of metal materials and bringing considerable economic and social benefit.

Rubber nanocomposites offer unique advantages over conventional polymer nanocomposites due to their exceptional flexibility, resilience, and dynamic mechanical properties, making them ideal for applications that require elasticity, impact resistance, and energy dissipation. Unlike rigid thermoplastic-based nanocomposites, rubber matrices can deform significantly while maintaining strong interfacial interactions with nanofillers, leading to materials with enhanced thermal stability, mechanical strength, barrier properties, and multifunctionality. This review presents recent advancements in rubber nanocomposites, highlighting the synergistic effects between elastomeric matrices and various nanofillers including silica, nanoclay, carbon nanotubes, and bio-based materials. Key processing techniques, including direct mixing, solution mixing, and in-situ polymerization, are discussed in relation to their impact on filler dispersion and composite performance. Industrial applications in tire manufacturing, electronics, biomedical devices, separation membranes, sporting goods, and catalysis are explored to showcase the broad potential of these materials. Despite remarkable progress, challenges remain regarding nanofiller dispersion, cost-effective scalability, environmental concerns, and long-term durability. Future directions include using artificial intelligence for material design, circular economy approaches for sustainable sourcing, and developing hybrid nanofiller systems. This review highlights the critical role of rubber nanocomposites in creating high-performance, flexible, and multifunctional materials for next-generation industrial applications.

We tested loading-unloading curves using nanoindentation and studied the mechanical properties of six polymer films, including polyethylene (PE), polypropylene (PP), polymethyl methacrylate (PMMA), Polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), and polyimide (PI). The loading-unloading curve is assumed to comprehensively reflect the relationship between intermolecular forces and intermolecular distances in polymer materials, and the force between organic molecules is usually the van der Waals force. We introduce the Lennard-Jones potential to describe the potential energy between the molecules of these materials and derive the intermolecular force as a function of the intermolecular distance. By fitting this relationship to the measured loading-unloading curves, it was found that they were consistent. Using the obtained fitting parameters, we calculated four mechanical parameters related to film compression: the binding energy between molecules on both sides of the cross-section per unit area (related to toughness); the binding force between molecules on both sides of the cross-section per unit area (related to strength); reduced Young’s modulus (related to stiffness); the total stretching distance between adjacent molecules stretched from the equilibrium position to the position where the binding force is maximum (related to the stretch performance of the material). The measured reduced modulus of PE, PP, PMMA, PTFE, PET, and PI films under zero stress/strain are 608.0, 42.8, 906.5, 36.1, 11.2, and 11.8 MPa, respectively. This research has the potential to develop an advanced and user-friendly universal testing tool for material mechanics, which can be utilized for sensing in robotics.

Here, the report on a facile synthesis of hemiamine thermoset containing iron oxide nanodomains by polycondensation of formaldehyde, polyetheramine (Jeffamine) D-400 and (3-aminopropyl)triethoxysilane (APTES) functionalized iron oxide nanoparticles is accomplished. The synthesized material was molded to required shapes by using high pressure mold press machine. Hemiamine thermosets were prepared by varying the percentage of APTES functionalized iron oxide nanoparticles as 5%, 10%, 15%, 20% and 25%. The characterizations of hemiamine thermoset were carried out by Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM). The augmentation of hemiamine with Fe₂O₃-NH₂ improved the thermomechanical characteristics in terms of glass transition temperatures (T_g,s) and tensile mechanical strength. The Young’s modulus and breaking strength was measured as 1.3 GPa and 72.5 MPa of the hemiamine thermoset containing 25% Fe₂O₃-NH₂ nanoparticles. The shape memory and self-healing properties were investigated. The impregnation of Fe₂O₃-NH₂ in hemiaminal dynamic covalent networks (HDCNs) was responsible of shape memory and self-healing properties due to improved thermal conductivity, reinforcement effect and interfacial interactions.

Two kinds of novel poly(arylene ether nitrile) copolymers (P-HFD and P-PFD) containing pendant aliphatic rings and fluorene groups were synthesized by 4, 4’-cyclohexane-1, 1’-diyldiphenol (CHDP) or 4, 4’-cyclopentane-1, 1’-diyldiphenol (CPDP), 4, 4’-(9-fluorenylidene) diphenol and 2, 6-dichlorobenzonitrile (DCBN) in this work. The inherent viscosities of these two copolymers were 0.455 and 0.576 dL/g. The copolymers P-HFD and P-PFD exhibited good thermal property, the glass transition temperatures (T_g) were 202.2–214.9 °C, and the weight-loss temperatures (T_5%) were 421.3–433.5 °C. The polymers’ films had good tensile strengths of 27.3–38.6 MPa. The result of dissolution experiment showed that the copolymers could be dissolved in some solutions at room temperature, such as NMP, DMF and CH₂Cl₂, implying they had good solubility, they can be processed by the solution method. Additionally, the optical transmittances of these two copolymers were 68.3–76.3% at 450 nm, indicating that they have the potential to be applied as the heat-resistant optical films.

The development of advanced electrode materials with high specific energy and robust cycling stability is critical for next-generation energy storage systems, including hybrid electric vehicles, solar energy harvesting, and grid-scale energy management. This work reports the in-situ synthesis of a ternary nanocomposite comprising polyaniline (PANI), benzene-1,2,4,5-tetracarboxylic acid (BTCA), and graphene oxide (GO), engineered to enhance supercapacitive performance. BTCA serves both as a dopant and structure-directing agent, facilitating the formation of uniform PANI nanorods and optimized at molar ratios of BTCA:aniline (1:4) and aniline:ammonium persulfate (1:1). Morphological analysis confirms homogeneous GO distribution, while selected-area electron diffraction reveals polycrystalline features. The composite exhibits excellent thermal stability (91% weight retention at 800 °C) and a BET surface area of 36.53 m²/g with type IV isotherm characteristics. Enhanced π-π stacking reduces chain disorder, improving conjugation length and charge transport. Electrochemical studies demonstrate dominant capacitive behavior where Nyquist plot reveal ~ 2.9Ω equivalent series resistance, ~ 0.0001978 Ω charge transfer resistance and the vertical-like tail at low frequencies demonstrates EDLC, achieving a specific capacitance of 274.8 F/g, energy density of 38.17 Wh/kg, and power density of ~ 1000 W/kg. Long-term cycling performance confirms 88% and 98% retention after 10,000 GCD and CV cycles respectively (two-electrode). Despite minor ohmic losses, the BTCA/PANI/GO composite in a device configuration while charged for approximately 40 s can glow a red LED for more than 90 s, offering a promising platform for high-performance supercapacitor electrodes with superior thermal resilience and electrochemical durability.

This study investigates the non-isothermal crystallization kinetics of polylactic acid (PLA), PLA/kenaf fiber (KF), and glycidyl methacrylate grafted polylactic acid (PLA-g-GMA)/KF biocomposites. Non-isothermal crystallization kinetics were analyzed with DSC, and crystallization morphologies were observed with POM. The Avrami, Ozawa, and Mo models described the non-isothermal crystallization kinetics. Determination of the half-time of crystallization (t_1/2) and Avrami-Jeziorny crystallization rate constant (Z_c) revealed that PLA/KF biocomposite reduced crystallization times across overall cooling rates and increased crystallization rates, indicating KF’s role as a nucleating agent. However, the crystallization rates of PLA/KF were hindered by the introduction of the PLA-g-GMA matrix. The Kissinger and Friedmann models agreed that activation energy (ΔE) for PLA/KF exhibited the lowest value, suggesting that KF accelerates the crystallization rate of PLA. Conversely, PLA-g-GMA/KF biocomposites exhibited the highest ΔE, providing direct kinetic evidence that the grafted GMA creates strong interfacial interactions with KF, which effectively restricts PLA chain mobility and dominates over the nucleating ability of the fiber. POM observations confirmed that KF promoted heterogeneous nucleation on PLA, while PLA-g-GMA inhibited crystallization by restricting PLA chain mobility.

It is well-established that molecular recognition concerning carrier agents is key in transporting and diffusing biologically active molecules across cell membranes. In this context, synthetic facilitated transport membranes (FTMs) have been utilized to extract and transport lactic acid (LA), a valuable compound with various industrial applications. We applied a PVDF-based Polymeric Inclusion Membrane (PIM) incorporating Aliquat 336 as the carrier, prepared via the standard phase inversion method. The resulting PIMs were subsequently characterized using infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and ATG-ATD thermal analysis. Macroscopic parameters, such as permeability (P) and initial flux (J₀), were evaluated to characterize membrane performance, while microscopic parameters, including the association constant (K_ass) and the apparent diffusion coefficient (D*), were determined to describe the transport mechanism of LA molecules through the membrane phase. These measurements were systematically performed by studying the effects of initial LA concentration (0.4, 0.5, 0.8, and 1 M), Aliquat 336 content in the membrane (20, 30, and 40 wt%), pH of the medium (2, 4, and 6), and temperature (298, 303, and 305 K). In addition, activation energy and thermodynamic parameters (E_a, ΔH^≠, ΔS^≠, and ΔH_th) were determined to explain the kinetic and energetic aspects governing the mechanisms of the processes. Data demonstrate that PIM-Aliquat 336 (30 wt%) displayed high effectiveness and performance in the extraction and recovery of the value-added compound LA, particularly in a medium with a pH of 6 with permeability (P) of 35.926 × 10⁻⁷ cm²·s⁻¹ and initial flux (J₀ ) of 16.750 × 10⁻⁵ mmol·cm⁻²·s⁻¹. These transport processes, generally directed by structural kinetic control within the PIM, remained efficient even at low temperatures, with activation energy (E_a) of 9.311 ∓ 0.199 kJ·mol⁻¹ and enthalpy of association ((:{varvec{varDelta:}varvec{H}}_{varvec{a}varvec{s}varvec{s}}^{ne:})) of 6.833 ∓ 0.199 kJ·mol⁻¹. Such characteristics make PIM- Aliquat 336 a promising membrane for the extraction and purification of temperature-sensitive biological compounds.