Enhancement Of Tensile Strength Research Articles

Current Advancements in the Behavior Analysis of EPDM Elastomers in Peripheral Applications of the Cathodic Side of PEMFC Systems

This review examines the latest developments in the study of how Ethylene Propylene Diene Monomer (EPDM) elastomers behave in peripheral applications of Proton Exchange Membrane Fuel Cells (PEMFCs), specifically on the cathodic side. The review highlights the crucial role of EPDM in maintaining the integrity and efficiency of PEMFCs in challenging conditions characterized by varying temperatures, humidity, and acidic environments. The study examines the impact of various additives and vulcanization procedures on EPDM's mechanical and chemical properties, demonstrating enhancements in tensile strength, thermal stability, and chemical resistance. The study also investigates the compounding methods and selection of fillers, such as silica and carbon black, to optimize the performance of EPDM. Additionally, the effects of prolonged operational circumstances on EPDM's mechanical integrity and aging resistance in PEMFCs are being examined. This research emphasizes EPDM's suitability for long-term use in fuel cell systems. This review aims to guide the design of more durable and efficient PEMFC systems by optimizing the use of EPDM elastomers.

Characterisation of AZ31/TiC composites fabricated via ultrasonic vibration assisted friction stir processing

In this study, the effect of ultrasonic vibration during Friction Stir Vibration Processing (FSVP) on the microstructure and mechanical behaviour of AZ31/TiC surface composites was investigated. Specifically, Titanium Carbide (TiC) particles were introduced as a reinforcement (15 vol%) into the magnesium alloy AZ31 using both Friction Stir Processing (FSP) and FSVP. Comprehensive examinations were carried out to analyse the microstructure, hardness, and tensile behaviour of the resulting composites. The study revealed significant improvements in mechanical properties due to the application of ultrasonic vibration during FSP. Firstly, the stir zone region was found to be free from voids, enhancing material flow and promoting even dispersion of TiC powders within the matrix. Secondly, refinement of grains was observed due to dynamic recrystallization and the pinning effect imposed by TiC particles, leading to the formation of more dislocations in the composite and indicating a considerable alteration in the material’s structure. Importantly, the vibration during FSP introduced an auxiliary energy source, resulting in a remarkable enhancement in both hardness and tensile strength. Compared to the AZ31/15 vol% TiC FSP composite, the composites produced via FSVP exhibited a grain size reduction of about 64% and improvements in hardness and ultimate tensile strength (UTS) of about 55% and 21%, respectively. Notably, these improvements were achieved without compromising the ductility of the composite, which remained at appreciable levels.

Superhydrophobic Electrospun PI/PTFE Membranes with Ultralow Dielectric Constants for High-Frequency Telecommunication.

High-frequency, high-power, and high-speed telecommunication in a complex environment promotes the development of dielectric materials toward a low dielectric constant, low dielectric loss, good thermal properties, and long-term reliability. Here, polyimide/polytetrafluoroethylene (PI/PTFE) nanofiber membranes with an inherent super hydrophobicity, excellent dielectric properties, good thermal stability, and enhanced tensile strength were prepared via a simple electrospinning strategy and an imidization reaction. The obtained PI/PTFE membranes demonstrate a superlow average dielectric constant of 1.22-1.27 and a dielectric loss of 0.032-0.048 in high frequency, together with an enhanced tensile strength, benefiting from the special nanofiber-bead structure formed in the composite membrane. The mixing of polyamic acid (PAA) and PTFE in the electrospinning solution endows the obtained PI/PTFE nanofiber membrane with a uniform distribution of PTFE and thus an inherent superhydrophobicity with a water contact angle of 156.1 and 159.2° for PI/PTFE-30% and PI/PTFE-40%, respectively. Besides, the hydrophobicity could be kept even after standing more than 10,000 water drops, and the thermal properties exhibited promising results with Tmax = 587 °C and Td5% = 423 °C, rendering these PI/PTFE membranes favorable alternatives for prospective telecommunication.

Influence of carbon nanotubes on the absorption performance and mechanical behavior of basalt fiber composite materials

AbstractBasalt fibers (BF) are widely used in shipbuilding due to their excellent corrosion resistance. However, basalt fibers do not possess good electromagnetic wave absorption properties, failing to meet the stealth performance requirements of ships. Therefore, this study focuses on basalt fiber composite materials, modifying the matrix by adding different amounts of carbon nanotubes (CNTs). Carbon nanotube‐basalt fiber‐epoxy resin absorptive composite materials are prepared using Vacuum Assisted Resin Transfer Molding (VARTM) technique to investigate the influence of CNT content on the materials. Samples with added CNTs can effectively absorb electromagnetic waves in the low‐frequency range, reducing surface reflectivity. In the high‐frequency range, the impedance matching value of the samples initially increases slowly. When the CNT content reaches 1.5 wt%, at a thickness of 2.5 mm and a frequency of 9.6 GHz, the minimum reflection loss of the sample is −14.40 dB, with an effective absorption bandwidth of 0.7 GHz. Also, CNTs can enhance the mechanical properties of composite materials. With increasing CNT content, both the bending strength and tensile strength of the composite materials are improved. When the CNT content reaches 1.5 wt%, the average tensile fracture strength of the material increases by 21%, and the bending strength increases by 9%.Highlights Enhanced low‐frequency electromagnetic wave absorption from CNTs and reduced polarization. Improved impedance matching and attenuation at high frequencies with CNTs. Significant enhancement in flexural and tensile strength due to CNTs and basalt fibers.

Effect of radiation-induced graft polymerization onto pineapple nonwoven fabric reinforced polymer composite

Natural fiber-reinforced polymer composites are gaining attention for their environmental benefits, such as biodegradability and reduced carbon footprint, as well as the potential of the natural fibers to replace or partially substitute synthetic fibers in various applications. However, challenges, such as poor interfacial adhesion and moisture absorption, limit the effectiveness of natural fibers, such as pineapple nonwoven fabric (PNWF) as reinforcement materials in polymer composites. To address these challenges, this study aims to enhance the properties of PNWF through glycidyl methacrylate grafting via radiation-induced graft polymerization. A 22 factorial design was employed to assess the effects of absorbed dosage and monomer concentration on the properties of the grafted PNWF. Infrared spectroscopy and electron microscopy analyses confirmed successful grafting. The grafted PNWF exhibited improved thermal stability and mechanical properties. The resulting composites showed significant enhancements in tensile and flexural strength, specifically, with tensile strength increase ranging from 23.32 to 34.49 MPa and flexural strength from 39.14 to 54.59 MPa. Additionally, the tensile modulus ranged from 0.77 to 1.29 GPa, while the flexural modulus varied from 1.17 to 2.06 GPa. These findings highlight the potential of PNWF grafted with polyglycidyl methacrylate (PNWF-g-PGMA) as an effective reinforcement material for various applications.

RHEOLOGICAL BEHAVIOR OF ALUMINUM SOAP: A NEW PROSPECT FOR TREAD RUBBER APPLICATION

ABSTRACT Aluminum soaps are notable for their enormous power of thickening many organic hydrocarbon solvents. We investigated the rheological behavior of aluminum dioleate, an aluminum soap, in squalane. Intriguingly, its linear rheological properties resembled those of entangled polymer melts, whereas its nonlinear behavior exhibited similarities to the Payne effect observed in particle-suspended systems. Using high-resolution microscopy, we discovered that its thickening power arises from the formation of spherical nanoparticles from the aluminum soap molecules that then aggregate into highly fractal networks in the dispersion medium. Remarkably, this nanoparticle formation occurs not only in small-molecule organic media but also in long-chain macromolecular rubber matrices, such as SBR. This discovery suggests that the aluminum soap may reinforce the polymer matrices and offer some rheological benefits in resulting rubber compounds. We then incorporated 10 phr of the aluminum soap into a silica-filled tread rubber formulation. The results revealed significant enhancements in tensile strength, accompanied by reduced rolling resistance. These promising outcomes highlight the practical application potential of aluminum soaps in tread formulations.

Highly Filled Waste Polyester Fiber/Low-Density Polyethylene Composites with a Better Fiber Length Retention Fabricated by a Two-Rotor Continuous Mixer

A key challenge in the utilization of waste polyester fibers (PET fibers) is the development of fiber-reinforced composites with high filler content and the improvement of fiber length retention. Herein, the effects of a two-rotor continuous mixer and a twin-screw extruder on the structure and properties of waste polyester fiber composites were evaluated. The results revealed that the mechanical properties of the composites were improved significantly with increasing fiber content, especially when processed using the twin-rotor continuous mixer. This mixer facilitated the formation of a robust fiber network structure, leading to substantial enhancements in tensile strength, flexural strength, and heat resistance. Specifically, compared to those processed by the twin-screw extruder, with 60 wt% fibers content, the tensile and flexural strengths of specimens processed by the twin-rotor continuous mixer increase by 21% and 13%, respectively. The average fiber length in specimens processed by the twin-rotor continuous mixer was 32% longer than that in specimens processed by the twin-screw extruder, attributable to the lower shear frequency and the higher tensile ratio of the former. This blending technique emerges as an effective strategy, contributing significantly to promoting the development and practical application of waste textile fiber-reinforced polymer composites.

Influence of silane and polyethylene glycol functionalization of boron nitride nanosheets on mechanical and thermal properties of epoxy nanocomposites: Machine and deep learning forecasting

AbstractThe influence of hexagonal boron nitride (hBN) nanosheet surface modification on epoxy nanocomposites' mechanical and thermal properties were investigated. An innovative approach was developed for synthesizing hBN nanosheets (hBNNs) via optimized ultrasonic‐assisted liquid‐phase exfoliation (UALPE), followed by functionalization with 3‐aminopropyltriethoxysilane (APTS) and polyethylene glycol (PEG600) for nanocomposite preparation. Compared to unmodified epoxy, nanocomposites containing 0.3 wt% of pristine hBNNs exhibited significant enhancements in flexural strength (125.28 MPa) and tensile strength (53.35 MPa), with respective increases of 40.57% and 43.23%. PEG‐hBNNs improved flexural and tensile strengths to 136.83 and 58.57 MPa, respectively. The most substantial enhancements were observed with APTS‐hBNNs, yielding flexural and tensile strengths of 174.13 and 63.53 MPa, reflecting increases of 95.37% and 70.50%, attributed to better interfacial interactions and a more effective crack deflection mechanism. Thermal stability analyses revealed superior performance of modified hBNNs epoxy nanocomposites, increasing 8.2°C and 6.3°C at 50 wt% degradation as compared to the unmodified system, owing to enhanced physical barrier properties. Structural and morphological analyses validated the successful exfoliation and modification of hBNNs. Predictive models utilizing machine and deep learning (DL) techniques, particularly DL with the adaptive moment estimation (ADAM) optimizer, effectively forecasted mechanical properties, achieving high R2 values.HIGHLIGHTS 0.3 wt% modified hBNNs epoxy nanocomposite showed the highest mechanical strength Improved thermal stability of epoxy nanocomposite by modification of hBNNs Improved crack deflection mechanism in the presence of surface‐modified hBNNs Deep learning with ADAM optimizer showed high R2 and low prediction loss

Optimization of TIG welding process parameters using Taguchi technique for the joining of dissimilar metals of AA5083 and AA7075

This research paper aims to optimize the TIG welding parameters to join dissimilar metals of AA5083 and AA7075 using the Taguchi technique. The TIG welding current and root gap of butt geometry configuration are considered input parameters, and welding characteristics such as tensile strength, 0.2% of yield strength, hardness, and impact energy are output responses. The base metals are joined according to the Taguchi L-09 design of experiments. The welded samples were inspected using the X-ray radiography method for internal defects. Tensile properties, hardness number, and impact energy of different welding coupons were evaluated by conducting the uni-axial testing, a Brinell hardness test, and an Izod impact test, respectively. A better weld strength of 224 MPa was observed at 210 A welding current, and the root gap of 1.5 mm was maintained. Better hardness and impact energy values were observed when the root gap of 1.5 mm and welding current of 220 A were maintained. The root gap is the primary factor influencing tensile strength enhancement, which accounts for 44.78% of the effect, followed by 40.5% welding current. Root gap is the parameter that affects the tensile properties, hardness number, and impact toughness the most. The findings of this paper suggest the optimal parameters for welding AA5083 and AA7075 dissimilar base metals, which are suitable for complex structures requiring both durability and resistance to harsh environments.

Innovation in sustainable composite research: Investigating graphene-reinforced MMCs for liquid hydrogen storage tanks in aerospace and space exploration

The demand for lightweight materials in space exploration applications has seen a significant rise. This study presents a novel approach by integrating graphene with Aluminium alloy (AA) 2900 powder, synthesized through High energy ball milling technique. The resulting powder was used to reinforce Aluminium alloy 2195, creating metal matrix composites (MMCs) via squeeze casting. The findings demonstrate that incorporating 0.5 wt % 2D graphene nanoplatelets (2D-Grnp) in AA 2195 achieved density match, enabling homogeneous dispersion, addressing composite casting challenges. Consequently, the AA 2900 alloy embedded with 2D-Grnp facilitated the homogeneous dispersion of reinforcements during the squeeze casting process, yielding MMCs Ideal for potential use in lightweight liquid hydrogen fuel tank structures for launch vehicles. Following T8 heat treatment, the final casted composite plate exhibited significant enhancements in ultimate tensile strength, with a 4.5% increase over monolithic Al 2195-T8, exhibiting nominal reduction in elongation behavior and higher hardness. Additionally, scanning and transmission electron microscopy (SEM, TEM), Small Angle Neutron Scattering (SANS) and Electron Backscatter Diffraction (EBSD) revealed the squeeze casting technique's effectiveness by exhibiting enhanced bonding among homogeneously reinforced 2D-Grnp, T1/θ’ precipitates, and AA 2195.

Elevating mechanical and thermal performance on alkali‐treated pineapple/glass fibre sandwich composite

AbstractThe present work generated hybrid composite sandwiches by incorporating 65% epoxy resin and 35% reinforcements derived from pineapple and glass fibres. The specimens were subjected to mechanical characterization by tensile, flexural and impact examinations. Among the untreated samples, the specimens containing untreated pineapple fibres (PF) with a composition of 17% PF, 18% glass fibres (three layers) and 65% epoxy by weight (17PF/TLGF) showed the most superior mechanical characteristics. Nevertheless, specimens containing fibres treated with NaOH exhibited exceptional characteristics, attaining a tensile strength of 88.121 MPa, a flexural strength of 94.213 MPa and an impact energy of 4.1 J. These data indicate a 20% enhancement in both tensile and flexural strength as well as a 63% improvement in impact strength compared to specimens containing 35% PF and lacking glass fibres (35PF/0GF). In comparison to 17PF/TLGF, the specimens treated with NaOH exhibited a 4.34% gain in tensile strength, a 4.24% increase in flexural strength and a 9% increase in impact strength. Experimental TGA was performed on the chemically treated fibre composite specimens, specifically identified as 35PF/0GF and 17PF/TLGF. Approximately 260 °C marked the beginning of decomposition for the 35PF/0GF sample, but the 17PF/TLGF sample decomposed at roughly 310°C. In addition, the fragmented surface of the 17PF/TLGF sample was analysed using SEM. © 2024 Society of Chemical Industry.

Effect of β nucleating agent and rotational shear on morphology and mechanical properties of polypropylene pipes

AbstractHerein, we report a new method of introducing circumferential shear to polypropylene (PP) pipes via a self‐designed rotational shear system (RSS) with the addition of a β‐nucleating agent (TMB‐5). The prepared PP pipes exhibited remarkable enhancement in toughening and tensile strength over conventional PP pipes incorporating 0.025 wt% of the nucleating agent into the sheared sample increased the elongation at break to 243.30%. At 0.05 wt% nucleating agent content, an optimal tensile strength of 40.98 MPa was attained compared to 33.62 MPa for unsheared PP, and the elongation at break also reached 108.09%. In creep tests, the PP pipes prepared with nucleating agents and shear rotation exhibited a minimum displacement of 2.1 mm and the lowest creep rate of 3.23 × 10−5 mm/s. In addition, the samples also showed a high resistance to crack growth compared to conventional PP pipes with a crack initiation time of 24 h and a crack growth rate of 0.08 mm/s.Highlights Reinforced and toughened PP pipes were prepared using a rotational shear system. The shish‐kebab structure and β‐crystals exhibited a synergistic effect. Both short‐term and long‐term mechanical properties were studied.

Experimental Study on Fiber Extraction after Saturated Steam Softening of Pleioblastus amarus

At present, bamboo fiber is mainly prepared by rolling and carding after employing the alkali boiling softening method, which is not friendly to the environment. In order to obtain a green and environmentally friendly pretreatment method for preparing bamboo fiber, this paper starts with the current bamboo softening technology and explores the impact of various experimental factors on fiber extraction of Pleioblastus amarus (bitter bamboo) after application of the saturated steam softening method through studying the relationship between saturated steam temperature, holding time, moisture content of bamboo strips, fiber yield, fiber fineness, and the mechanical properties of Pleioblastus amarus fiber. Single-factor experiments revealed that optimal softening fiber extraction effects were achieved within a steam temperature range of 150–180 °C, a holding time of 10–30 min, and a moisture content of 12%–22%. Based on these findings, an orthogonal experiment was designed using a factorial-level table. Through the analysis of range, variance, and orthogonal experiment results, combined with the fibrillation effect and the practical application of fibers, the optimal process parameters of the saturated steam softening method for fiber extraction were determined: saturated steam temperature 170 °C, holding time 20 min, and moisture content 12%. In contrast to the method of conventional mechanical fiber extraction after alkali boiling softening treatment, bamboo fibers processed utilizing the optimized conditions of the saturated steam softening technique showcase a substantial 63% elevation in fiber yield, a notable 18% reduction in fiber fineness, a commendable 28% enhancement in fiber tensile strength, an equivalent tensile modulus, and a marked 53% decrease in elongation at break. The softening process can provide a green and environmentally friendly treatment method for bamboo fiber extraction and greatly promote the scope of application of Pleioblastus amarus.

Hierarchically Structured Cellulose Acetate@Silk Protein Membrane with Enhanced Mechanical and Electromagnetic Interference Shielding Performances.

Compared to conventional fibers, electrospun porous nanofibers with hierarchical structures often involve additional active sites, interfaces, and internal spaces which boost the performances of functional materials. Here in this study, coaxial composite cellulose acetate@silk fibroin (CA@SF) fibrous membranes are constructed through an electrostatic spinning technique combining solvent-induced phase separation. Hierarchical core-shell structures on the fibers are achieved, which significantly increases the surface area and benefits the mechanical property, flux, as well as the electroless deposition of Ag nanoparticles. The total electromagnetic shielding efficiency of the sandwiched hierarchical CA@SF@Ag composite membrane with a thickness of only 100 μm reaches up to 100 dB, surpassing around 82% beyond nonhierarchical ones. To be noticed, when post-treated by ethanol, the membrane enables an enhanced tensile strength of up to 10 MPa with a thickness of only 50 μm. Our findings pave the way to the application of electrospun fiber membranes in the field of ultrathin electromagnetic shielding films.

Refinement of microstructure and improvement of mechanical properties of directed energy deposited titanium alloys by adding Fe

Elemental alloying is a validated strategy for enhancing the mechanical properties of directed energy deposited titanium alloys. However, it is still a challenge to obtain titanium alloys with both high strength and high ductility. In this work, to balance strength and ductility, the alloying element Fe was in-situ added to the TC4 melt pool during the directed energy deposited process and the effects of its content on the microstructure and mechanical performance of the TC4 alloy deposits were investigated. The results showed that the Fe additive ranging from 0.5 to 2.0wt.% were completely solid-solved in the retained β phase of TC4 alloys. Moreover, the primary β columnar grains were transformed into fully equiaxed grains. Meanwhile, the presence of Fe refined the α-laths, increased the proportion of the retained β phase, and the continuous grain boundary α (GB-α) became discontinuous. The tensile strength of the deposited alloys was continually improved with increasing Fe content, while the elongation had a peak value. When the Fe content was 1.0wt.%, the deposited alloy exhibited the best comprehensive performance, with an ultimate tensile strength of 1071MPa and an elongation of 9.3%. The enhancement of tensile strength was attributed to the solid solution strengthening and the refinement of α-laths and primary β grains. The increased proportion of retained β phase and the formation of discontinuous GB-α were beneficial for the alloy ductility. However, increased α/β interfaces inhibited dislocation movements, resulting in a decrease in ductility. The development of this alloy is important for aerospace and other fields that require high strength, high ductility and lightweight.

A novel approach to improving the interfacial strength of 3D printed Al–GNP composites by modifying GNP with MgO

In this study, the MgO-coated graphene nanoplatelets (GNP)-reinforced aluminum matrix AlSi10Mg composites are fabricated by mechanical alloying and a 3D printing process. The interfacial structure of GNPs–Al has been investigated using high-resolution transmission electron microscopy, and their strengthening mechanism has been analyzed. A weak amorphous Al2O3 was found at the GNP–Al interface area in the composites made with uncoated GNPs. The structure of amorphous Al2O3 becomes distorted when load transfer is initiated, causing the detachment of GNPs from the matrix. This results in quick failure at the interface between uncoated GNPs and aluminum, restricting its overall strength. Once GNPs are coated with MgO, an Al/C mixing zone forms at the contact area, resulting in increased interface strength. The MgO coating on the GNP serves as a protective barrier, preventing the creation of a weaker amorphous Al2O3 layer at the interface and facilitating direct interaction between the GNP and Al matrix. The stress–strain curve demonstrates a 27.5% enhancement in tensile strength in the MgO-coated GNP–Al composite compared to the composite with uncoated GNPs. The strength is increased while maintaining toughness through load transmission of GNPs, bridging, and enhancing dislocation storage capacity by the Mg-rich phase. This study offers a new reference for strengthening 3D-printed aluminum alloys using GNPs.

Fabrication of kenaf fiber reinforced boron carbide fillers embedded epoxy matrix composite – An antimicrobial and structural analysis

This study investigates the incorporation of boron carbide (B4C) filler particulates into a kenaf fiber-reinforced epoxy matrix to explore its potential in lightweight applications, focusing on antimicrobial effectiveness, mechanical integrity, thermal properties, and microstructural characteristics. The composite material was formulated by blending varying seven different concentrations of boron carbide (0–50 g) and kenaf fibers (KFs) with an epoxy resin, aiming to achieve a balance between mechanical strength and minimal weight. Antimicrobial test revealed that the composite material, consisting of kenaf fiber reinforced with B4C particulates, exhibited significant antibacterial activity against common pathogens. Mechanical testing indicated that the addition of boron carbide and kenaf fibers significantly improved the tensile strength and flexural rigidity of the composites. Specifically, enhancements in tensile strength and flexural modulus were quantitatively analyzed, showing notable increases compared to the base epoxy resin. Scanning Electron Microscopy (SEM) was employed to examine the fracture surfaces following mechanical testing, revealing improved interfacial bonding between the kenaf fibers and the epoxy matrix due to the presence of boron carbide. This microscopic analysis also highlighted areas where stress distribution was optimized, contributing to the composite's enhanced mechanical properties.

Linear polydichlorophosphazene and Ti3C2Tx MXene nanohybrids: Synthesis and application to epoxy resin to improve the fire safety and mechanical properties

Enhancing the fire safety of epoxy resins (EPs) typically requires a significant amount of flame retardants, which often results in considerable degradation of their mechanical properties. To address this issue, a novel flame retardant known as PDCP@DPA@MXene was synthesized and integrated into EP to achieve notable improvements in flame retardancy, smoke suppression, and mechanical strength. By incorporating 1.5 wt% PDCP@DPA@MXene, the impact strength, tensile strength, and elongation at break of the resulting PDM-1.5 %/EP composite reached 12.1 kJ/m2, 57.4 MPa, and 13.0, respectively, reflecting enhancements of 63.5 %, 18.4 %, and 17.1 % compared to the pure EP. The enhancement in tensile strength may be attributed to the high rigidity of Ti3C2Tx MXene, which reinforces the EP matrix. Additionally, the intertwined structure of PDCP@DPA@MXene chains effectively mitigates material fracturing and absorbs impact forces, thus toughening the EP. The presence of phosphorus, nitrogen, and titanate in PDCP@DPA@MXene contributes to the formation of a more compact char layer. The PDM-1.5 %/EP sample achieved a V-0 rating in the vertical UL-94 test and exhibited a high limiting oxygen index of 32.0. Furthermore, the sample containing 2 wt% PDCP@DPA@MXene showed a significant reduction in peak heat release rate (p-HRR) and total heat release (THR), recording values of 689 kW/m2 and 71.9 MJ/m2, which are decreases of 45.1 % and 26.9 %, respectively, compared to pure EP. Additionally, the incorporation of PDCP@DPA@MXene led to a reduction in CO production. These flame-retarded EPs demonstrate strong potential for various applications due to their elevated glass transition temperature and robust thermal stability.

Study on the enhancement of paper tensile strength and hydrophobicity by adding PEI-KH560 in pulp suspension

Novel eco-friendly strength agent has inspired much attention of researchers. Herein, the PEI-KH560 prepared by PEI (polyethyleneimine) and KH560 (γ-glycidyl ether propyl trimethoxysilane) was added in the pulp suspension to enhance the paper performance. The results showed that the m(PEI):m(KH560) ratio and PEI's molecular weight were closely related with the paper strength and hydrophobicity. The SEM morphology of paper surface showed that the fiber-fiber crosslinking reached the tightest, at the optimal m(PEI):m(KH560) ratio and PEI's molecular weight. The results showed that when the Mw (molecular weight) of PEI was 10,000 and the m(PEI):m(KH560) ratio was 1:2, the PEI-KH560 presented the best strengthening performance on the paper strength and hydrophobicity. Dry tensile index and wet tensile index could reach 29.9 N·m/g and 1.37 N·m/g after adding the PEI10000-KH560 in pulp suspension before the paper formation. Further, the effect of process conditions (temperature, time, the addition amount, and pulp concentration) on the strength and hydrophobicity of paper network structure was investigated, after adding PEI-KH560 into the pulp suspension. It was of great significance for studying the mechanism between the chemical structures of PEI-KH560 and paper performance, which provided valuable theoretical practice on the preparation of novel strength agent.

Creating ultra-strong and recyclable green plastics from marine-sourced alginate-chitosan nanowhisker nanocomposites for controlled release urea fertilizer

In response to the pressing environmental challenge posed by petroleum-derived plastics, the development of green plastics derived from all-biomass nanocomposites offers promising solutions. However, conventional nanocomposites often prioritize enhanced stiffness at the expense of flexibility. We introduce sodium alginate (SA)/chitosan nanowhisker (CSW) nanocomposites, derived entirely from marine-sourced all-biomass, to create ultra-strong and flexible green plastics. Through the synergistic interaction between SA and CSW, these nanocomposites demonstrate simultaneous stiffening and toughening, overcoming the traditional trade-off. Two key mechanisms contribute: geometric reinforcement from the needle-like structure of CSW and electrostatic reinforcement at the interface between oppositely charged CSW and SA. Compared to control SA, the SA/CSW nanocomposites exhibit remarkable enhancements in tensile modulus, strength, and stretchability, by 49%, 85%, and 55%, respectively (7.6 GPa, 223.3 MPa, 14.7%). Cellulose nanocrystals, serving as a control, only stiffen the nanocomposites, adhering to the typical trade-off. Biodegradability in compost can be tailored based on the type of nanofillers. Due to the water resistance of CSW, SA/CSW nanocomposites are proven effective for the controlled release of urea fertilizer in agricultural applications. With recyclability and superior mechanical properties, these marine-sourced green plastics offer a sustainable alternative to conventional plastics, promising significant impact in the eco-plastic industry.