Journal of Applied Polymer Science最新文献

With the rapid development of aerospace technology, solid rocket motors have put forward higher requirements for the comprehensive performance of insulation materials. Chloroprene rubber (CR) is widely regarded as an ideal matrix for thermal insulation materials due to its excellent tensile strength, high elongation at break, and good flame-retardant properties. In this study, a flexible and ablation-resistant composite insulation material was prepared by adding nano cerium oxide (CeO₂) to the CR/poly-p-phenylene terephthamide pulp (PPTA-pulp) composite matrix, and the effect of CeO₂ on its mechanical and ablation-resistant properties was systematically studied. Based on this, a three-component thermal conductivity model of CR/PPTA-pulp/CeO₂ was constructed, and molecular dynamics simulations were carried out with Reverse Non-Equilibrium Molecular Dynamics (RNEMD) to predict its thermal conductivity. The results show that when the amount of CeO₂ is added at 0.25 phr, the tensile strength and elongation at break are increased by 25.9% and 17.6%, respectively, while the linear ablation rate and thermal conductivity are reduced by 52.0% and 16.9%, respectively. The positive role of CeO₂ in enhancing the ablation performance of materials was confirmed by molecular dynamics simulation.

With the aim of developing a high-performance flame-retardant epoxy resin (EP), (oxiran-2-ylmethyl)diphenylphosphine oxide (DPO-EP) was synthesized via the epoxidation of allyldiphenylphosphane oxide and subsequently employed as a reactive flame retardant. Flame-retardant EP samples with various phosphorus contents were prepared by curing blends of diglycidyl ether of bisphenol A (DGEBA) and DPO-EP, using 4,4′-diaminodiphenylsulfone (DDS) as the curing agent. Among these, the EP sample containing 0.6 wt% phosphorus (EP/DPO-EP/0.6) exhibited a limiting oxygen index (LOI) value of 32.9% and achieved a UL-94 V-0 rating. In the cone calorimeter test, EP/DPO-EP/0.6 showed significant reductions in peak heat release rate (57.3%) and total heat release (14.0%) compared to pure EP. Mechanistic studies revealed that DPO-EP primarily exerted its flame-retardant effect through the release of phosphorus-containing radicals and non-flammable gases in the gas phase, while simultaneously facilitating the formation of a compact char layer in the condensed phase. Furthermore, the incorporation of DPO-EP accelerated the curing process of EP without compromising its transparency. In addition, the dielectric constant and dielectric loss of EP were reduced by the introduction of DPO-EP. The combination of high flame retardancy, excellent transparency, and improved dielectric properties renders DPO-EP-modified EP a promising candidate for advanced applications in electronic and optical fields.

This work tackles the challenge of flame-retarding high-porosity (porosity > 70%) polyphenylene oxide-polystyrene (PPO/PS) composite foams with traditional condensed-phase flame retardants. A synergistic system of phosphate ester (PX220) and brominated compound (BPS) was developed, relying on gas-phase flame retardancy (primary) and condensed-phase barrier/smoke suppression (supplementary). Their complementary decomposition temperatures enable timely gas-phase product release to suppress PPO/PS thermo-oxidative degradation, while PX220's plasticization improves BPS dispersion. For unfoamed samples, the system achieved a maximum LOI of 36.4%, with HRR reduced by up to 17 MJ/m² (4.8% higher than single systems). It also lowers smoke release via intumescent char. For 85% porosity foams, LOI reached 25.4% (HF-1 pass), and even at > 90% porosity, HRR and melt dripping were suppressed. Moreover, PX220 and BPS refine cell morphology (via viscosity reduction and heterogeneous nucleation), increasing compressive strength by 0.67 MPa at 85% porosity. This study provides a novel flame-retardant approach and strategy for lightweight, high-performance PPO/PS composite foams.

Rigid polyurethane foam (RPUF) is widely recognized as an ideal building material due to its low thermal conductivity and excellent compressive strength. However, achieving flame retardancy in RPUF typically requires high loadings of flame retardants, which can compromise the mechanical properties of the foam. In this study, a two-component waterborne flame-retardant coating (PA_x), composed of ammonium polyphosphate (APP) and polydopamine (PDA), is developed for the flame-retardant modification of RPUF. Experimental results indicate that surface modification with a minimal amount of PDA (1:75, mass ratio of PDA to APP) improves the dispersibility of APP in aqueous solution, resulting in a stable waterborne coating. With the aid of PDA mediated adhesion, APP firmly adheres to the surface of RPUF, forming a dense and stable flame-retardant layer. The PA_x-coated foam (RPUF-PA₁₅) demonstrates excellent flame-retardant performance, achieving a limiting oxygen index (LOI) of 50.9% and meeting the UL-94 V-0 rating. Additionally, the compressive strength of RPUF-PA₁₅ (733.5 kPa) is 6.4% higher than pristine RPUF (689.3 kPa). In conclusion, an efficient waterborne flame-retardant coating has been successfully developed, achieving efficient flame retardancy for RPUF and providing a solid foundation for the development of such coatings.

To address the synergistic removal of Congo Red (CR) and hexavalent chromium (Cr(VI)) from industrial wastewater, this study proposed an “electrospinning-surface modification” strategy. Using poly(vinyl alcohol-co-ethylene) (PVA-co-PE) as the substrate, a dual-functional composite nanofibrous membrane adsorbent (PVA-co-PE/chitosan (CS)/polydopamine (PDA)) was constructed via CS grafting and PDA coating. The structural and physicochemical properties of the PVA-co-PE/CS/PDA NF membranes were characterized by elemental mapping, spectroscopic analyses, and morphological observation, while batch experiments were conducted to investigate the adsorption behavior and key influencing factors. Results showed that the composite membrane exhibited maximum adsorption capacities of 716.9 mg/g for CR and 264.4 mg/g for Cr(VI), with the adsorption process conforming to the Langmuir monolayer adsorption model and pseudo-second-order kinetic model (dominated by chemical adsorption). After four adsorption–desorption cycles, the membrane retained adsorption capacities of 609.3 mg/g for CR and 224.5 mg/g for Cr(VI), demonstrating excellent cyclic stability. With advantages of simple preparation, strong recyclability, and negligible secondary pollution, the proposed composite membrane serves as a novel, efficient adsorbent for the synergistic advanced treatment of organic dyes and heavy metal ions in complex industrial and holds substantial engineering application value.

Rigid polyurethane foam (RPUF) is widely recognized as an ideal building material due to its low thermal conductivity and excellent compressive strength. However, achieving flame retardancy in RPUF typically requires high loadings of flame retardants, which can compromise the mechanical properties of the foam. In this study, a two-component waterborne flame-retardant coating (PA_x), composed of ammonium polyphosphate (APP) and polydopamine (PDA), is developed for the flame-retardant modification of RPUF. Experimental results indicate that surface modification with a minimal amount of PDA (1:75, mass ratio of PDA to APP) improves the dispersibility of APP in aqueous solution, resulting in a stable waterborne coating. With the aid of PDA mediated adhesion, APP firmly adheres to the surface of RPUF, forming a dense and stable flame-retardant layer. The PA_x-coated foam (RPUF-PA₁₅) demonstrates excellent flame-retardant performance, achieving a limiting oxygen index (LOI) of 50.9% and meeting the UL-94 V-0 rating. Additionally, the compressive strength of RPUF-PA₁₅ (733.5 kPa) is 6.4% higher than pristine RPUF (689.3 kPa). In conclusion, an efficient waterborne flame-retardant coating has been successfully developed, achieving efficient flame retardancy for RPUF and providing a solid foundation for the development of such coatings.

Epoxy-modified polysulfide is widely used in coatings and as an adhesive for rocket insulation. Understanding the curing process is essential for enhancing the properties of the material. This research investigates the curing kinetics of epoxy-modified polysulfide and examines how curing temperature influences its characteristics. In the study, epoxy, polysulfide, and cycloaliphatic amine curing agents are mixed and cured at 25°C, 40°C, and 60°C. The curing durations are determined based on a kinetics model. The curing kinetics are analyzed using differential scanning calorimetry (DSC), employing the Prout-Tompkins autocatalytic method for modeling. Changes in molecular structure during the curing process are assessed using second derivative analysis from Fourier Transform Infrared Spectroscopy (FTIR). Additionally, the mechanical properties such as hardness, tensile strength, elongation, elastic modulus, and density are measured using a Shore D durometer, a universal testing machine, and a densitometer. Phase separation is examined with a scanning electron microscope (SEM). The results indicate that higher curing temperatures increase density, hardness, tensile strength, and elastic modulus by factors of 1.013, 2.38, 1.75, and 14.95, respectively, while reducing flexibility by 0.75 times. Although phase separation does not occur, higher temperatures do affect the product's opacity.

Poly(ethylene oxide) (PEO) is a promising candidate to fabricate solid polymer electrolytes (SPEs). To improve the comprehensive performances of PEO-based SPEs, vinylidene fluoride (VDF) copolymers grafted with poly(ethylene glycol) were electrospun and applied as a support for the PEO matrix. The grafting of PEG onto the VDF copolymer was achieved by the nucleophilic substitution of a chlorine atom in the VDF copolymer by methoxy-polyethylene-glycol thiol. The ionic conductivity of the VDF copolymer was increased with the grafting site density of PEG at the same bis(trifluoromethane sulfonimide) (LiTFSi) concentration. SPEs were fabricated by solution casting of PEO/LiTFSi onto electrospun VDF graft copolymer fibers. Electric field poling induces a beneficial α-to-β phase transition in the VDF copolymer, and the compatibility between the VDF copolymer and PEO was improved due to the incorporated PEG side chains, which facilitate lithium ion (Li⁺) transport through additional conduction pathways and enhance lithium-ion solvation. The supported PEO SPEs exhibited good mechanical strength and toughness, and the optimized SPE with an EO/Li ratio of 6:1 exhibits excellent electrochemical performance at 60°C, including an ionic conductivity of 1.79 × 10⁻⁴ S cm⁻¹, a Li⁺ transference number of 0.49, and a wide ESW of 5.46 V (vs. Li⁺/Li).

This study reports the synthesis of an inherently hydrophobic, bio-based polyurethane foam (Bio-HPUF) derived from hemp seed oil (HSO) for efficient oil–water separation. Unlike conventional polyurethane foams, Bio-HPUF was synthesized without solvents, blowing agents, or catalysts, using HSO-derived polyol and hexamethylene diisocyanate (HDI). Structural characterization via FTIR confirmed successful urethane formation, while SEM revealed an open-cell porous morphology with pore sizes ranging from 163–567 $��\mu �$m. Thermal analysis showed multi-stage degradation with stability up to 330°C. The foam exhibited a water contact angle of 91° and an oil contact angle of 16°, indicating hydrophobic and oleophilic behavior. It demonstrated selective sorption capacities up to 1–27.8 g/g for oils and organic solvents, rapid oil uptake within 15 s, and high selectivity in water. Reusability studies showed minimal loss in performance over 10 oil adsorption–desorption cycles. The foam also maintained $��>�$ 99% of its original mass after 24 h exposure to acidic, saline, and basic media, with no structural degradation. Notably, Bio-HPUF effectively separated toluene-in-water emulsion, showed excellent compression recovery with self cleaning abilities, affirming its applicability in complex systems. These results highlight the material's sustainable synthesis, structural robustness, and high selectivity, positioning it as a promising sorbent for environmental oil remediation.