Hybrid Polymer Research Articles

Liposomal rose bengal and its butyl ester derivative formulations for antimicrobial photodynamic therapy

Patients with cystic fibrosis are highly susceptible to bacterial infections, which can often lead to irreversible damage. In this context, inhalable liposomal systems have shown great promise as drug delivery mechanisms, significantly enhancing drug permeation and accumulation in the lungs. However, the development of inhalable liposomes for various therapeutic applications is still in its early stages, providing ample opportunities for extensive research by the scientific community. Within this scenario, antimicrobial photodynamic therapy may emerge as a relevant technique, promoting greater selectivity due to its light trigger. We have developed lipid–polymer hybrid liposomes (DPPC/F127) and compare the inclusion of two types of xanthenes, one more hydrophilic (Rose Bengal - RB) and one more hydrophobic (Rose Bengal butyl ester - RBBUT). The systems were characterized in terms of morphology, thermal and kinetic stability, incorporation and release efficiency, photophysical properties, and possible location of the PS in the liposome. The studies showed that incorporation into DPPC/F127 prevented self-aggregation and significantly improved the photophysical properties of RB and RBBUT. The bacterium Pseudomonas aeruginosa proved to be more resistant to the photodynamic effect, requiring long illumination times. For Staphylococcus aureus, we observed a dependence between pre-incubation time and illumination time. Our results showed that the more external photosensitizer (PS) was more effective in experiments performed without incubation. However, with pre-incubation, the efficacy of both systems became comparable. Notably, only 10 min of illumination (warm white light; fluence: 139.7 J cm⁻2) resulted in complete bacterial inactivation.

Synthesis of ZnO/Poly(Styrene‐co‐Methacrylic Acid) Hybrid Polymer Particles for Enhanced UV‐Visible Photodegradation of Methylene Blue

AbstractIn this study, a series of submicron‐sized functional polymer particles poly(Sty‐co‐MAA) with variable methacrylic acid (MAA) content were prepared by soap‐free emulsion polymerization of styrene (Sty), methacrylic acid (MAA), and ethylene glycol dimethacrylate (EGDMA). The number‐average diameters of polymer particles (Dn) were in the range of 0.11 to 0.19 μm. A decrease in particle size was observed with increasing the molar ratio of MAA comonomer in the recipe. ZnO/poly(Sty‐co‐MAA) hybrid polymer particles were prepared by seeded emulsion copolymerization in presence of zinc oxide nanoparticles (ZnO NPs) as seed particles synthesized using Citrus lemon aqueous leaf extract. Scanning electron microscopy (SEM), transmission electron microsphere (TEM), X‐Ray Diffraction (XRD), and Fourier transformed infra‐red (FT‐IR) analysis were performed to characterize polymer particles. The crystalline size of ZnO NPs and ZnO/poly(Sty‐co‐MAA) hybrid polymer particles calculated from XRD analysis were 20.75 and 29.85 nm, respectively. These hybrid polymer particles were applied as photocatalyst in the photodegradation of methylene blue (MB) dye under UV irradiation, which showed high catalytic activity with degradation efficiency of 85.70 % at room temperature compared to bare ZnO NPs.

Halochromic Bacterial Cellulose/Anthocyanins Hybrid Polymer Film with Wound-Healing Potential.

Polymer-based dressings deriving from natural biomaterials have advantages such as nontoxicity, biocompatibility, and mechanical stability, which are essential for efficient wound healing and microbial infection diagnostics. Here, we designed a prototype of an intelligent hydrogel dressing on the base of bacterial cellulose (BC) for monitoring wound microbial infection due to the uploaded natural pH dye-sensor, anthocyanins (ANC) of elderberry fruit (Sambucus nigra L.). The highest sensor responses to bacterial metabolites for ANC immobilized to BC were observed at pH 5.0 and 6.0. The detection limit of the sensor signals was 3.45 A.U., as it was evaluated with a smartphone-installed application. The FTIR spectral analysis of the hybrid BC/ANC hydrogel films has proved the presence of anthocyanins within the BC matrix. Hybrid films differed from the control ones by thicker microfibrils and larger pores, as detected with scanning electron microscopy. Halochromic BC/ANC films exhibited antimicrobial activities mainly against gram-positive bacteria and yeast. They showed no cytotoxicity for the in vitro human cell lines and mouse fibroblasts within a selected range of anthocyanin concentrations released from the BC/ANC film/dressing prototype. Compared to the control, the in vitro healing test showed overgrowth of primary mouse fibroblasts after applying 0.024-2.4 µg/mL ANC.

Transferred Chiroptical Transitions in Chiral Binaphthyl /π‐Conjugated Polymer Hybrid Films: Significance of Aromatic Solvent‐Mediated Co‐Crystallization

Transferred Chiroptical Transitions in Chiral Binaphthyl /π‐Conjugated Polymer Hybrid Films: Significance of Aromatic Solvent‐Mediated Co‐Crystallization

Lipid polymer hybrid nanoparticles against lung cancer and their application as inhalable formulation.

Lung cancer is a leading cause of global cancer mortality, often treated with chemotherapeutic agents. However, conventional approaches such as oral or intravenous administration of drugs yield low bioavailability and adverse effects. Nanotechnology has unlocked new gateways for delivering medicine to their target sites. Lipid-polymer hybrid nanoparticles (LPHNPs) are one of the nano-scaled delivery platforms that have been studied to exploit advantages of liposomes and polymers, enhancing stability, drug loading, biocompatibility and controlled release. Pulmonary administration of drug-loaded LPHNPs enables direct lung deposition, rapid onset of action and heightened efficacy at low doses of drugs. In this manuscript, we will review the potential of LPHNPs in management of lung cancer through pulmonary administration.

Inhaled Ivermectin-Loaded Lipid Polymer Hybrid Nanoparticles: Development and Characterization.

Ivermectin (IVM), a drug originally used for treating parasitic infections, is being explored for its potential applications in cancer therapy. Despite the promising anti-cancer effects of IVM, its low water solubility limits its bioavailability and, consequently, its biological efficacy as an oral formulation. To overcome this challenge, our research focused on developing IVM-loaded lipid polymer hybrid nanoparticles (LPHNPs) designed for potential pulmonary administration. IVM-loaded LPHNPs were developed using the emulsion solvent evaporation method and characterized in terms of particle size, morphology, entrapment efficiency, and release pattern. Solid phase characterization was investigated by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Using a Twin stage impinger (TSI) attached to a device, aerosolization properties of the developed LPHNPs were studied at a flow rate of 60 L/min, and IVM was determined by a validated HPLC method. IVM-loaded LPHNPs demonstrated spherical-shaped particles between 302 and 350 nm. Developed formulations showed an entrapment efficiency between 68 and 80% and a sustained 50 to 60% IVM release pattern within 96 h. Carr's index (CI), Hausner ratio (HR), and angle of repose (θ) indicated proper flowability of the fabricated LPHNPs. The in vitro aerosolization analysis revealed fine particle fractions (FPFs) ranging from 18.53% to 24.77%. This in vitro study demonstrates the potential of IVM-loaded LPHNPs as a delivery vehicle through the pulmonary route.

Rational Design of Hybrid Electrolyte for All-Solid-State Lithium Battery Based on Investigation of Lithium-Ion Transport Mechanism

Lithium-ion batteries (LIBs) are widely used in various applications, including personal electronic devices, electric vehicles, and energy storage systems. Given the increasing demand for LIBs, there is need to develop rechargeable batteries with high energy densities, long cycle life, and enhanced safety. Lithium all-solid-state batteries (ASSBs) could improve operational safety by eliminating flammable liquid electrolytes and using non-flammable solid electrolytes. Among the various types of solid electrolytes explored, solid polymer electrolytes (SPEs) have garnered significant attention owing to their desirable properties, such as good processability, light weight, flexibility, and favorable interfacial contact with the electrodes. To develop practical battery systems using SPEs, improving the ionic conductivity mechanism of lithium-ion (Li+) in SPEs is crucial. Li+ transport mechanism of SPE is typically known as segmentation motion and ion hopping. In SPE, crystalline and amorphous phases coexist, and movement of Li+ occurs mainly in the amorphous phase. Therefore, the use of SPE at high temperatures improves ionic conductivity, but still that have limitation by low ionic conductivity (10-7~ 10-8 S cm-1) at ambient temperatures, low Li+ transference numbers, a restricted electrochemical window, and low mechanical strength. Hybrid polymer electrolytes (HPEs) combine an inorganic ceramic electrolyte (ICE) and SPE to create a ceramic-in-polymer or a polymer-in-ceramic hybrid and have improved ionic conductivity and mechanical stability compared to SPE. Ceramic materials of HPE can be classified into oxide-based materials and NASICON-type materials. Oxide-based materials such as SiO2, Al2O3, etc. induce an increase in the amorphous area of PEO and improve segmental mobility by preventing recrystallization of the polymer, thereby increasing ionic conductivity. NASICON-type materials, such as Li7La3Zr2O12 (LLZO), Li1+xAlxTi2-x(PO4)3 (LATP), etc. are promising candidates for improving ionic conductivity by increasing the mobility of Li+ because they form ionic conductive channels within the ceramic bulk. However, despite the observed improvements in performance, the Li+ ion transport mechanism in HPEs and its correlation with the electrochemical cell results remain unclear.In this study, we present a new approach to improve the performance of ASSB by establishing the Li+ transport mechanism through a designed HPE system proven through experimental results and density functional theory (DFT) calculations. To achieve high energy density ASSB, LiNi0.8Co0.1Mn0.1O2 (NCM811) Li ASSB cell was applied, and through a combination of experiment and DFT calculation, HPE was manufactured by PEO-based semi-interpenetrating polymer network (semi-IPN) SPE and Li1+xAlxTi2-x(PO4)3 (LATP) of NASICON-type. As a result, we confirmed that Li+ migrates through the interface of SPE and LATP, which has a significant effect on the improved ionic conductivity (7.23 × 10-4 S cm-1 at 45 ℃). In addition, it was confirmed that Li dendrites were suppressed and cycle performance were improved due to the improved physical strength of the electrolyte with the addition of ceramics. This suggests a promising design strategy for high-performance Li ASSB.

Experimental insights into the stability of graphene oxide nanosheet and polymer hybrid coupled by ANOVA statistical analysis

The synergistic potential of using graphene oxide (GO) nanosheets and hydrolyzed polyacrylamide (HPAM) as GO enhanced polymer hybrid (GOeP) for enhancing oil recovery (EOR) purposes has drawn attention. However, the hybridization method and stability of GOeP have not been comprehensively studied. To cover this gap, the current study evaluates the stability of GOeP under different conditions, including temperatures such as 60 and 80 °C, high and low salinities, and the presence of Mg2+ ions (6430 and 643 ppm). Hence, GO nanosheets were synthesized and characterized through XRD, Raman, FTIR, and DLS techniques. The performance of five preparation methods was assessed to determine their ability to produce stable hybrids. Zeta potential and sedimentation methods, coupled with the ANOVA statistical technique, were used for measuring and interpreting stability for 21 days. Results revealed that the stability of GOeP in the presence of brine is influenced by hydrolyzation duration, the composition of the water used in polymer hydrolyzation, the form of additives (being powdery or in aqueous solution), and the dispersion quality, including whether the GO solution was prediluted. The results revealed that the positive impact of higher temperatures on the long-term stability of GOeP is approximately seven times less significant than the reduction in stability caused by salinity. Under elevated salinity conditions, a higher Mg2+ concentration led to an 80% decrease in long-term stability, whereas the temperature impact was negligible. These findings highlight the potential of GOeP for EOR applications, offering insights into optimizing stability under challenging reservoir conditions.

Controlled Radical Copolymerization toward Tailored F/N Hybrid Polymers by Using Light‐Driven Organocatalysis

AbstractControlled radical copolymerizations present attractive avenues to obtain polymers with complicated compositions and sequences. In this work, we report the development of a visible‐light‐driven organocatalyzed controlled copolymerization of fluoroalkenes and acyclic N‐vinylamides for the first time. The approach enables the on‐demand synthesis of a broad scope of amide‐functionalized main‐chain fluoropolymers via novel fluorinated thiocarbamates, facilitating regulations over chemical compositions and alternating fractions by rationally selecting comonomer pairs and ratios. This method allows temporally controlled chain‐growth by external light, and maintains high chain‐end fidelity that promotes facile preparation of block sequences. Notably, the obtained F/N hybrid polymers, upon hydrolysis, afford free amino‐substituted fluoropolymers versatile for post modifications toward various functionalities (e.g., amide, sulfonamide, carbamide, thiocarbamide). We further demonstrate the in situ formation of polymer networks with desirable properties as protective layers on lithium metal anodes, presenting a promising avenue for advancing lithium metal batteries.

Controlled Radical Copolymerization toward Tailored F/N Hybrid Polymers by Using Light-Driven Organocatalysis.

Controlled radical copolymerizations present attractive avenues to obtain polymers with complicated compositions and sequences. In this work, we report the development of a visible-light-driven organocatalyzed controlled copolymerization of fluoroalkenes and acyclic N-vinylamides for the first time. The approach enables the on-demand synthesis of a broad scope of amide-functionalized main-chain fluoropolymers via novel fluorinated thiocarbamates, facilitating regulations over chemical compositions and alternating fractions by rationally selecting comonomer pairs and ratios. This method allows temporally controlled chain-growth by external light, and maintains high chain-end fidelity that promotes facile preparation of block sequences. Notably, the obtained F/N hybrid polymers, upon hydrolysis, afford free amino-substituted fluoropolymers versatile for post modifications toward various functionalities (e.g., amide, sulfonamide, carbamide, thiocarbamide). We further demonstrate the in situ formation of polymer networks with desirable properties as protective layers on lithium metal anodes, presenting a promising avenue for advancing lithium metal batteries.

Nanocomposites of Glass/Sisal Fibre Strengthened Hybrid Polymer Matrix and the Effect of SiC Nanofillers on its Mechanical Features

Introduction: This study investigates the mechanical characteristics of hybrid sisal fibre (SF)/glass fibre (GF) reinforced composites with various weight % of nSiC fillers (nano silicon carbide). SF/GF/nSiC reinforced hybrid composite materials were developed following ASTM specifications using the vacuum infusion technique. Method: The resulting composites were then evaluated for their tensile, impact, hardness, and flexural characteristics. The findings reveal that none of the composites can imitate the GF composite's mechanical advantages despite hybridization and the nanofiller addition. The hybrid composite laminates with 2 wt.% nSiC show better mechanical response than competing hybrid composites. Results: The GF/SF/2%nSiC composite's impact strength and shore D hardness of the GF/SF/2%nSiC composite are 1.25 and 1.2 times greater than those of the GF/SF/3%nSiC composites. The GF/SF/2%nSiC composites exhibit 1.64, 1.5, and 1.8 times higher tensile strength, tensile modulus, and toughness modulus than the GF/SF/3%nSiC composites. The GF/SF/2%nSiC composite has a flexural modulus and strength of 1.22 and 1.41 times higher than the GF/SF/3%nSiC composites. Conclusion: The improved mechanical properties of the GF/SF/2%nSiC composite can be attributed to the firm bond between the fibre and matrix, the uniform dispersion of nanofillers, and reduced porosity. result: The tensile, impact, hardness, and flexural properties of the developed composites were assessed. SEM of the fractured surface was also performed to corroborate the results and determine the fracture mode.

Thermomechanical properties of multifunctional polymer hybrid nanocomposites based on carbon nanotubes and nanosilica

AbstractNanocomposites containing low wt% of oxidized multi‐walled carbon nanotubes (MWCNT‐OXI), nanosilica (NS), and its hybrid (MWCNT‐OXI/NS) in epoxy resin were produced and evaluated. The used nanoparticles were studied by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Raman spectroscopy while the nanocomposites were investigated in relation to its morphology, thermal, and mechanical properties. The results demonstrated significant improvements in the storage modulus (E′), glass transition temperature (Tg), and cross link density (CD), for the produced nanocomposites. Increases in thermal conductivity (TC) of up to 85% at 90°C were observed for the nanocomposites containing 1.0 wt% of the hybrid MWCNT‐OXI + NS nanofiller, when compared with neat polymer. It was also verified increases in the resistance to plastic deformation for the nanocomposites, maintained the polymer thermal stability with the addition of these nanoparticles. Finally, the use of MWCNT‐OXI and NS, combined or not, significantly improved the thermal and mechanical properties of polymer, showing multifunctional characteristics for the produced nanocomposites.

Achieving a High‐Strength Bonding between Aluminum Alloys and Polymer Composites via Self‐Riveting Welding

Great challenges exist in producing reliable welding between metals and polymer composites. In this study, self‐riveting welding (SRW) is employed to obtain metal–polymer hybrid joints with high load‐bearing capability. In this investigation, it is shown that the SRW joints with a prefabricated hole of 5.8 mm in diameter are characterized by fewer void defects with sufficient polymer filling, a tightly bonded joint interface, and a relatively uniform stress distribution along the joint interface during the tensile test, leading to the high load‐bearing capability of the SRW joints. The maximum average tensile force is 1.5 kN. The fracture occurs across the polymer composite rather than along the joint interface. In the results, it is shown that SRW has the potential to be developed into a method for fabricating reliable hybrid joints for the aerospace and automotive industries.

Hybridization of Polymer-Encapsulated MoS2-ZnO Nanostructures as Organic-Inorganic Polymer Films for Sonocatalytic-Induced Dye Degradation.

The development of environmentally friendly technology is vital to effectively address the issues related to environmental deterioration. This work integrates ZnO-decorated MoS2 (MZ) to create a high-performing PVDF-based PVDF/MoS2-ZnO (PMZ) hybrid polymer composite film for sonocatalytic organic pollutant degradation. An efficient synergistic combination of MZ was identified by altering the ratio, and its influence on PVDF was assessed using diverse structural, morphological, and sonocatalytic performances. The PMZ film demonstrated very effective sonocatalytic characteristics by degrading rhodamine B (RhB) dye with a degradation efficiency of 97.23%, whereas PVDF only degraded 17.7%. Combining MoS2 and ZnO reduces electron-hole recombination and increases the sonocatalytic degradation performance. Moreover, an ideal piezoelectric PVDF polymer with MZ enhances polarization to improve redox processes and dye degradation, ultimately increasing the degradation efficiency. The degradation efficiency of RhB was seen to decrease while employing isopropanol (IPA) and p-benzoquinone (BQ) due to the presence of reactive oxygen species. This suggests that the active species •O2- and •OH are primarily responsible for the degradation of RhB utilizing PMZ2 film. The PMZ film exhibited improved reusability without substantially decreasing its catalytic activity. The superior embellishment of ZnO onto MoS2 and effective integration of MZ into the PVDF polymer film results in improved degrading performance.

Toward highly ionic polyelectrolyte membrane: Synthesis, characterization, membrane performance and theoretical studies of PVDF-g-PAN/PAMPS hybrid membranes

Novel highly ionic polyvinylidene fluoride (PVDF) membranes grafted with an acrylonitrile monomer to yield the target (PVDF-g-PAN) via radical polymerization and then blended with the amphiphilic copolymer poly (2-acrylamido-2-methyl-1-Propane sulfonic acid (PAMPS) via physical interactions (PVDF-g-PAN)/(PAMPS), were designed and constructed. The new functional groups obtained (fluoride, nitrile, and sulfonic functions) were confirmed via FTIR analysis, and the prepared membranes were characterized using SEM, TGA, tensile strength, water contact angle, and mechanical stability instruments. The essential characteristics of the polyelectrolyte membranes, including the IEC, ionic conductivity, methanol permeability, thermal stability, and high mechanical qualities, were examined. It was discovered that, the oxidative stability of the modified membrane (P3) with a high concentration of conductive PAMPS affected the percentage of weight loss (5.25 %) at the end of 24 h. In addition, the water absorption capacity increased with increasing in the concentration of PAMPS. Similarly, the highly concentrated PAMPS modified membranes (P3) have an ionic exchange capacity and proton conductivity equal to IEC= 1.93 meq/g, which is greater than that of the Nafion membrane by 0.91 meq/g. Furthermore, appropriate DFT theoretical studies such as EHOMO, ELUMO, energy band gap and dipole moment (µ) were thoroughly examined and employed to validate the highly ionic system. It was found that, the energy band gap of PVDF-g-PAN/PAMPS was 5.19 eV, which is lower than that of the grafted polymer value (7.17 eV), confirming that the electrons are transferred readily from the HOMO level to the LUMO level. In addition, the dipole moment of the PVDF-g-PAN/PAMPS was 7.10 Debye, which is greater than the dipole moment value of the grafted polymer (2.07 Debye), indicating the highly ionic character of the hybrid polymer. Finally, the promising results obtained demonstrated favorable film-forming and structural properties, making it a promising option for polyelectrolyte membranes. It also has the added advantage of being cost-effective and can be applied in many electrochemical applications.

Fabrication of ramie/hemp fibers-reinforced hybrid polymer composite—A comprehensive study on biological and structural application

This study primarily investigates the antibacterial properties, tensile strength, flexural strength, impact strength, hardness, and microstructural characteristics of a composite, utilizing Scanning Electron Microscopy (SEM) for detailed analysis. The composite, crafted through a hand layup technique, optimally blends ramie and hemp fibers within an epoxy matrix. Its antibacterial efficacy was rigorously tested against common bacterial strains, demonstrating significant potential for medical and hygienic applications. The evaluation of tensile strength revealed the composite’s enhanced capability to withstand longitudinal stresses, with a peak strength of 37.81 MPa, achieved by increasing ramie fiber content. In addition, a flexural strength of 39.72 MPa underscored the material’s robust resistance to bending forces, crucial for structural uses. The composite’s impact strength, accessed via the Izod impact test, registered at 0.021 J/m2, indicating its ability to absorb and dissipate energy upon sudden impacts, making it ideal for automotive and protective gear applications. The Rockwell hardness test further quantified the composite’s resistance to surface indentation, vital for wear-resistant surfaces. SEM analysis offered a comprehensive view of the microstructural dynamics between the fibers and the matrix, especially under tensile stress, highlighting the intricacies of fiber–matrix adhesion, crack propagation, and overall composite integrity. Notably, the antibacterial properties were confirmed by an 18 mm inhibition zone, which showcases the composite’s ability to inhibit bacterial growth effectively.

Application of artificial SEI layers for lithium metal battery anodes

Unpredictable lithium dendrite growth on the metal anode and repeated destruction and creation of the solid electrolyte interphase (SEI) layer result in hidden risks and low Coulombic efficiencies (CEs). Researchers have found that designing a high-quality SEI layer can prevent the growth of dendrite. However, designing and forming a high-quality SEI layer is still a problem. Making trade-off between capacity reduction caused by the SEI layer and better cycle stability significantly limits the general performance of lithium metal batteries. In this research, characteristics of SEI layers and some significant advancements made in SEI formation are outlined. Some designs for the SEI layers on the lithium metal anodes include designing hybrid polymer SEI layers, producing synthetic SEI layers. By controlling the behaviours of Li ions throughout the stripping and depositing processes, the capacity and stability of Li metal anodes may be improved. Finally, some case studies of the applying of SEI in lithium metal battery systems are introduced.

Investigation of Tensile and Impact Properties of Pineapple Leaf Fiber-Glass Fiber Reinforced Polymer (GFRP) Hybrid Composites

Kontes Kapal Cepat Tak Berawak Nasional (KKCTBN) held by Pusat Prestasi Nasional (Puspresnas) Kemendikbudristek RI aims to encourage innovation in the design and performance of shipping-maritime technology prototypes. The selection of the right material for the catamaran hull is very important because it affects the strength and weight of the ship. Materials such as fiber reinforced polymer, which uses glass fiber, are often used due to their good mechanical strength. However, natural fibers such as pineapple leaf fiber also have potential as composite reinforcement. The combination of natural and synthetic fibers, such as pineapple leaf fiber and glass fiber, in hybrid composites can improve the mechanical properties of the material. The purpose of this study was to investigate tensile and impact properties of pineapple leaf fiber-glass fiber reinforced polymer (GFRP) hybrid composites. Fiber preparation was carried out by separating pineapple leaf to produce fibers, alkaline treatment using 10% NaOH with a soaking time of 24 hours, and oven drying at 100?C for 60 minutes. Polymer as the matrix used was 50% while the percentage variations of pineapple leaf fiber and glass fiber were sequentially as follows 5%:45%, 10%:40% and 15%:35%. It was found that the tensile strength of the 10% pineapple leaf fiber composite was about 114 MPa and impact strength 49.96 J/mm², density 1.19 g/cm3. The results of this study indicate that the resulting composite can be used as an alternative material in the prototype hull of a catamaran type unmanned speedboat.

Development and characterization of hybrid polymer composite materials with reinforcement of glass/carbon fibers for enhanced mechanical properties: an experimental and numerical approach

Composite materials, particularly fiber-reinforced plastics (FRP), are used in aerospace and automotive industries due to their desirable properties and surpassing traditional metals in various applications. Researchers are countering the drawbacks of using a single fiber type in FRP by creating hybrid composites that combine different fibers in a single matrix. These hybrids harness the cost-effectiveness and corrosion resistance of glass fibers alongside the strength and stiffness of carbon fibers, resulting in a balanced combination of properties for various applications. Tensile tests were performed according to the ASTM D3039 standard, with a 2 mm/min strain rate. The results showed that increasing the carbon fiber percentage (6.56%, 13.79%, and 21.07%) led to significant improvements in the tensile strength of the hybrid composites (34.18%, 55.44%, and 85.40% higher than glass fiber composites). However, changing the stacking sequence did not significantly affect tensile strength, indicating its insignificance in this regard. Numerical simulations were conducted to validate the experimental results, and the errors between experimental and numerical data were below 10% for various stacking sequences. These discrepancies were attributed to factors such as fiber waviness, which resulted in heterogeneous property distribution within the composites, and the manufacturing process used for creating the hybrid composites. Scanning electron microscope analysis was also performed to study the failure modes on the fracture surface of the tensile-tested specimens.

Development of a quaternary photocurable system for 3D printing based on the addition of acrylate monomers to an epoxy/thiol‐Ene system

AbstractThe exothermic nature of acrylate photopolymerizations enables room temperature 3D printing of a quaternary formulation that incorporates an acrylate monomer, and an epoxy/thiol‐ene system (ETES). The latter comprises an epoxy monomer, a multifunctional thiol and a tetraallyl functionalized ditertiary amine curing agent. Pristine ETES necessitates temperatures of 85–95 °C for curing. Several mechanisms operate simultaneously during this process: homopolymerization of acrylates, thiol‐acrylate photopolymerization, thiol‐ene photopolymerization between the double bonds of curing agent and the multifunctional thiol, the Michael addition between thiolates derived from ETES and the double bonds of acrylates, and the anionic polymerization of the epoxy resin via the tertiary amine groups. To optimize the quaternary formulations for printing, parameters, such as reactivity, exothermicity, and viscosity, was explored. Subsequently, the thermal and viscoelastic properties of the printed cross‐linked polymers derived from these formulations were analyzed using Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA) and Thermogravimetric Analysis (TGA). The polymers derived from quaternary formulations exhibited lower crosslinked density compared to those obtained from the pristine acrylates. This reduction in crosslink density contributes to the improved toughness of the hybrid polymers.