Journal of Applied Polymer Science最新文献

Twenty types of polyethylene (PE) including high density polyethylene (HDPE) and linear low-density polyethylene (LLDPE) with various viscosity were used to study the in-situ formation of PE- ethylene propylene rubber (EPR) core-shell rubber particles (CSRP) in polypropylene (PP) matrix by melt blending. The results show that PE and EPR cannot form CSRP if PE melt flow index (MFI) is lower than about 0.3 g/10 min. As a result, the impact fracture of PP/PE/EPR composite is brittle. If PE MFI is higher than 0.3 g/10 min, PE and EPR can form CSRP, leading to the ductile impact fracture of PP/PE/EPR composite. Interestingly, upper limit content of PE for the formation of CSRP depends on the type and viscosity of PE. For HDPE, upper limit content of PE tends to increase with the increase of its MFI, whereas it drops considerably for LLDPE. Understanding these relationships provides insights into optimizing the selection of core types and viscosity for enhancing the mechanical properties of polymer composites with core-shell structure. This may potentially guide the development of cost-effective and high-performance polymer composites.

Hemostatic materials used in penetrating injuries or incompressible wounds must possess exceptional efficacy in preventing bleeding. In this study, mesoporous bioglass (MBG) was synthesized using a two-step acid-catalyzed self-assembly method, and a novel hemostatic sponge (MBG/CH/GEL) was prepared by combining chitosan (CH), gelatin (GEL), and MBG using a freeze-drying method. The characteristics and hemostatic effects of the MBG/CH/GEL composite hemostatic sponge were analyzed and evaluated. Research has shown that the high specific surface area of MBG (730 m²/g) provides more blood cell adhesion sites during hemostasis, resulting in a low hemolysis rate, favorable swelling rate, and porosity of the hemostatic sponge. Additionally, MBG can release Si⁴⁺ and Ca²⁺ ions during hemostasis, giving the composite hemostatic sponge excellent cell compatibility and promoting cell growth. Compared with commercially available gelatin hemostatic sponges, it cannot only quickly stop bleeding but also has a greater compressive strength (212.07 kPa) and adhesion strength (11.54 ± 0.16 kPa), making it suitable for use in hemostasis of incompressible wounds. Furthermore, the composite hemostatic sponge exhibited significant antibacterial effects against Staphylococcus aureus and Escherichia coli. These results indicate that the MBG/CH/GEL composite hemostatic sponge, which is a hemostatic material, has promising applications.

In this study, the reaction of six natural phenolic aldehydes, namely, ethyl vanillin (EV), syringaldehyde (SA), vanillin (VA), isovanillin (ISA), 2-hydroxy-4-methylbenzaldehyde (HDA), and p-hydroxy benzaldehyde (PHDA), with chitosan produces Schiff bases of chitosan films. All the complex films were characterized through instrumental analysis. The findings suggested that the degrees of substitution of CS-EV, CS-SA, CS-VA, CS-ISA, CS-HDA and CS-PHDA were 73.48%, 42.22%, 58.04%, 51.52%, 40.89% and 45.23%, respectively. The results of X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) analysis confirmed that natural phenolic aldehydes conjugated with chitosan through dynamic imine bonds. The tensile strength and water barrier properties of the films were significantly better than those of the chitosan film. Film thermal stability was altered as a result of the grafting of natural phenolic aldehydes on chitosan. According to the ABTS and DPPH data, the blended films showed better antioxidant packaging performance.

Selective adsorption plays an important role in the resource utilization of dye wastewater. Hydrated calcium silicate (CSH), as an ideal adsorption material, is successfully compounded on the surface of polypropylene (PP) fibric by quasi-solid-phase method, and porous calcium silicate film is formed on the surface of PP fabric. The contact angle of the surface of PP fibers is changed from 130.7° to 62.4° due to the hydrophilic characteristics of CSH and polyvinyl alcohol. The adsorption for dyes shows obvious selectivity, and the removal ratio for methylene blue can reach more than 90%, while there is almost no adsorption for methyl orange. The obvious selectivity can be attributed to the electrostatic interaction between CSH and dyes. CSH contains silicate anion chains, resulting in a large number of negatively charged sites distributed on the surface, which may be the main reason for the adsorption for cationic dyes through electrostatic interactions. The investigation of adsorption kinetics shows that the formation of coordination bonds between calcium silicate and methylene blue will also lead to further enhancement of adsorption capacity.

Poly(butylene adipate-co-butylene terephthalate) (PBAT)/thermoplastic starch (TPS) blends were prepared by melt blending. However, the processability and practical application of PBAT/TPS blends are limited by their poor compatibility. To enhance the compatibility between PBAT and TPS, PBAT was functionalized by maleic anhydride (MA) to prepare PBAT-MA, and then it was employed as a compatibilizer for PBAT/PBAT-MA/TPS blends. The effects of PBAT-MA on the tensile properties, rheological properties, morphology, and dynamic mechanics of PBAT/PBAT-MA/TPS blends were studied in detail. Rheological results revealed that the interaction between PBAT-MA and TPS enhanced the segment entanglement ability and improved the compatibility of the blends, which enhanced the tensile properties of the blends. Compared with the PBAT/PBAT-MA/TPS (50/0/50) blend, the tensile strength of the PBAT/PBAT-MA/TPS (40/10/50) blend increased from 9.2 to 15.8 MPa, and the elongation at break increased from 326.9% to 1017.6%. The dynamic mechanical results showed that the T_g of PBAT and TPS were close to each other after the addition of PBAT-MA, which confirmed that the compatibility of the blend was improved. This study provides a feasible approach to preparing high-performance and cost-effective PBAT/PBAT-MA/TPS blends while expanding the application prospects of PBAT in the packaging industry and agricultural film.

The unique morphology of thermoplastic vulcanizates (TPVs) reveals a significant correlation between the microstructure and performance, and the development of high-performance TPV composites for specialized applications has become a current research priority. This study is devoted to developing heat- and oil-resistant TPV composites filled with carbon black (CB) based on hydrogenated acrylonitrile butadiene rubber (HNBR) and thermoplastic polyester elastomer (TPEE) following the masterbatch procedure of dynamic vulcanization. Herein, it focuses on the effects of CB content on the morphology, filler network structure, and properties of the TPV/CB composites. As observed by morphological studies, CB nanoparticles are interconnected and aggregated to form a dual network structure of rubber and CB particles in the composite. With the increasing CB content, it's demonstrated that dual networks have enhanced and shifted to rigid. Consequently, the hardness, thermal stability, and oil resistance of TPV/CB composites are improved, with a 104% elevation in the stress at 300% strain. The flowability in the molten state, toughness (the elongation at break decreased from 690% to 310%), and elasticity deteriorated by oversized (0.5 ~ 1.2 μm) CB agglomerates and rigid rubber particles. This study gives new insight into the microstructure-properties relationship of TPVs, offering theoretical guidance for fabricating HNBR-based TPV composites.

In this study, two cardanol based epoxidized resins, NC514 with less than two epoxies per molecule and side chain epoxidized cardanol glycidyl ether (SCECGE) with approximately 2.45 epoxies (1.0 phenolic+1.45 aliphatic epoxies) per molecule were methacrylated. The methacrylated versions of cardanol based NC514 (NC514VE) and SCECGE (SCECGEVE) epoxy resins were used as cross-linker units in vinyl ester formulations with methacrylated lauric acid (MFA) and styrene (ST) as bio-based and synthetic based reactive diluents respectively, at various concentrations (10–40 wt%). The curing reactions of the resins were studied via FTIR and the extent of polymerization was determined for different cross-linker units in the presence of ST and MFA. Our mechanical and thermomechanical characterizations showed that VER formulations prepared with cardanol based SCECGEVE cross-linker unit have significantly improved properties than the samples prepared with commercially available counterpart NC514VE using either reactive diluent. These properties of SCECGEVE were also comparable with to that of methacrylated petroleum-based diglycidyl ether of bisphenol A vinyl ester (DGEBAVE) formulations unlike NC514VE formulations due to more effective side chain functionalization and cross-linking.

Contaminated water sources from various industries pose severe environmental challenges due to their complex compositions, high toxicity, and fluctuating qualities. This study introduces a groundbreaking strategy for fabricating advanced polysulfate (PSE) ultrafiltration membranes using a novel reverse thermally induced phase separation (RTIPS) process. By manipulating the cloud point through the DMAc/DEG solvent/nonsolvent system, our work innovatively controls membrane microstructure, overcoming limitations of conventional nonsolvent-induced phase separation (NIPS). Our findings reveal that RTIPS, when employed above the cloud point, yields PSE membranes with a unique bicontinuous sponge-like structure, significantly improving upon conventional NIPS products. Specifically, the optimized RTIPS membranes exhibit enhanced pure water flux (916.23 vs. 336.23 LMH), larger pore sizes (0.083 vs. 0.054 μm), increased tensile strength (1.32 vs. 0.84 MPa), and improved fouling resistance (FRR 65.5% vs. 55.2%). This research pioneers a facile yet potent method for tailoring membrane properties, achieving a balance between permeability, mechanical stability, and filtration efficacy. The demonstrated success of RTIPS in enhancing PSE membrane performance not only contributes to the development of high-performance water treatment technologies but also charts a new course in membrane science, offering a promising avenue for sustainable wastewater management solutions.

With the development of electronic devices and wireless communication technology, the quality of human life has improved. However, shielding from electromagnetic interference (EMI) is required due to device malfunctions and harmful effects on human health. Polymer-based shielding materials getting much attention due to their light weight, flexibility, good processability, and other desirable traits. However, achieving consistent dispersion of conductive fillers and optimizing the balance between electrical, mechanical, and thermal properties remain challenges despite the advantages of polymer-based materials. Especially, epoxy resins are promising polymer materials for EMI shielding applications due to their excellent mechanical strength, chemical resistance, and excellent adhesive properties. Additionally, epoxy resin exhibits remarkable processability allowing for various fabrication techniques such as casting, molding, and three-dimensional printing. However, one of the significant drawbacks of epoxy resin is the difficulty in achieving uniform dispersion of conductive fillers within the epoxy matrix. In this study, we propose an iron-nickel alloy (FeNi) embedded in an epoxy matrix (FeNi/Epoxy) for EMI shielding material. It is manufactured by facile fabrication process due to the advantages of epoxy, which has excellent processability. EMI shielding effectiveness at 12 GHz is enhanced from 9.12 to 17.86 dB by the increase of FeNi concentrations. Furthermore, thermal and mechanical properties were improved by the increase of FeNi concentration. Thermal conductivity for efficient heat dissipation is increased from 0.63 to 1.49 Wm⁻¹ K⁻¹. Moreover, polydopamine (PDA) was employed as a surface coating material for FeNi to overcome the non-uniform dispersion of FeNi particles in the epoxy matrix. Surface coating by PDA significantly enhanced the dispersion uniformity and strengthened the adhesion between the filler and matrix. Elastic modulus is greatly increased from 83.03 MPa to 1.29 GPa by the surface coating. The enhancement of mechanical properties is derived from the chemical bonds between the filler and matrix.

This research explores the development of new composite material by integrating Azadirachta Indica (AI) with LLDPE to create wood-plastic composites using the rotational molding process. By examining various proportions of AI wood flour blended with LLDPE, we investigated their impact on mechanical and physical properties. Our tests elucidate a clear correlation between mechanical properties and composite morphologies. Despite identical molding conditions, higher wood particle concentrations reduced mechanical properties compared to lower concentrations. Remarkably, a 12% wood content emerges as optimal, yielding a tensile modulus of 3.69 MPa and a flexural modulus of 468.5 MPa, with an acceptable reduction of 11% density and 13% porosity versus pure LLDPE. Additionally, we observed declines in tensile strength, impact strength, and hardness by up to 23%, 62%, and 11%, respectively, compared to neat LLDPE. Natural fillers enhance aesthetics, making these materials ideal for consumer products like garden equipment and furniture accessories.