Improvement In Impact Strength Research Articles

Machine learning strategy to improve impact strength for PP/cellulose composites via selection of biomass fillers

ABSTRACT Lignocellulosic materials have inherent complexities and natural nanoarchitectures, such as various chemical constituents in wood cell walls, structural factors such as fillers, surface properties, and variations in production. Recently, the development of lignocellulosic filler-reinforced polymer composites has attracted increasing attention due to their potential in various industries, which are recognized for environmental sustainability and impressive mechanical properties. The growing demand for these composites comes with increased complexity regarding their specifications. Conventional trial-and-error methods to achieve desired properties are time-intensive and costly, posing challenges to efficient production. Addressing these issues, our research employs a data-driven approach to streamline the development of lignocellulosic composites. In this study, we developed a machine learning (ML)-assisted prediction model for the impact energy of the lignocellulosic filler-reinforced polypropylene (PP) composites. Firstly, we focused on the influence of natural supramolecular structures in biomass fillers, where the Fourier transform infrared spectra and the specific surface area are used, on the mechanical properties of the PP composites. Subsequently, the effectiveness of the ML model was verified by selecting and preparing promising composites. This model demonstrated sufficient accuracy for predicting the impact energy of the PP composites. In essence, this approach streamlines selecting wood species, saving valuable time.

Mechanical Properties of Basalt / Chopped E-Glass Fiber and Graphite Powder Reinforced Hybrid Composites

In the current investigation an effort has put to study the effect of E-glass chopped mat and graphite powder in variations of 5g, 10g, and 15g on the tensile and flexural behavior of a basalt fiber-reinforced epoxy composite laminate reinforced with E-Glass fiber and Graphite powder. Hand layup technique has been used for the fabrication of the composites. Tensile, flexural, impact, and hardness tests were done on the Basalt/E-glass/Graphite epoxy composite in accordance with ASTM standards. The results indicate significant improvement in tensile strength, impact strength and hardness when E-glass was incorporated in the basalt/epoxy composite. However, basalt/E-glass/10% graphite epoxy composite was shown to have a greater flexural strength. An excellent dispersion of the reinforcements in the polymeric matrix, which elevated surface area for solid interfacial contact and effective load transmission, could possibly be accountable for the improved performance of the laminates that were successfully developed.

Synergistic effects of organosilicon flame retardant and DOPO-based reactive compatibilizer for high performance PC/PBT composites

PC/PBT alloy is flammable resulting in fire safety hazards in practical applications and the existing flame retardants have a great influence on the mechanical properties, which limits its application range. Therefore, it is an urgent problem to improve the flame retardancy of PC/PBT alloy while taking its mechanical properties into account. Herein, a novel flame retardant and reactive compatibilizer was synthesized by grafting 9,10-dihydro-9-oxa-10-phosphophenanthrene-10-oxide (DOPO) onto ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA), named as DOPO-EG, to improve the flame retardancy and mechanical properties of PC/PBT alloy simultaneously. Additionally, based on the effective synergistic effect of enhancing the charring and flame retardancy between silicon and phosphorus, the organosilicon flame retardant (RMSi) is introduced and compounded with DOPO-EG to prepare excellent flame retardancy PC/PBT/DOPO-EG/RMSi composites. The results showed that the PC/PBT/DOPO-EG/RMSi composites with 10 wt% DOPO-EG and 8 wt% RMSi (CBE10P10Si8) reached UL-94 V-0 rating and the peak of heat release rate (PHRR) and total heat release rate (THR) of CBE10P10Si8 decreased by 42% and 16% respectively. This is due to the fact that DOPO is cracked into phosphorus radicals to capture and eliminate the active H and OH radicals, inhibiting the chain free radical reaction, and RMSi is enriched on the surface of CBE10P10Si8 to form an inorganic oxygen insulation protective layer during combustion. The impact strength of CBE10P10Si8 increased from 5.8 kJ/m2 to 11.9 kJ/m2. The improvement of impact strength is owing to the existence of DOPO-EG which promotes the formation of the interface layer between PC and PBT phases, resulting in the transfer of stress between the two phases. This work provides a new method for the preparation of PC/PBT alloy with excellent flame retardancy and mechanical properties, and also provides a certain reference value for the research of flame retardancy and toughening modification of polymer composites.

Cross-Linked Polyolefins through Tandem ROMP/Hydrogenation.

Cross-linked polyolefins have important advantages over their thermoplastic analogues, particularly improved impact strength and abrasion resistance, as well as increased chemical and thermal stability; however, most strategies for their production involve postpolymerization cross-linking of polyolefin chains. Here, a tandem ring-opening metathesis polymerization (ROMP)/hydrogenation approach is presented. Cyclooctene (COE)-co-dicyclopentadiene (DCPD) networks are first synthesized using ROMP, after which the dispersed Ru metathesis catalyst is activated for hydrogenation through the addition of hydrogen gas. The reaction temperature for hydrogenation must be sufficiently high to allow mobility within the system, as dictated by thermal transitions (i.e., glass and melting transitions) of the polymeric matrix. COE-rich materials exhibit branched-polyethylene-like crystallinity (25% crystallinity) and melting points (Tm = 107 °C), as well as excellent ductility (>750% extension), while majority DCPD materials are glassy (Tg = 84 °C) and much stiffer (E = 710 MPa); all materials exhibit high tensile toughness. Importantly, hydrogenation of olefins in these cross-linked materials leads to notable improvements in oxidative stability, as saturated networks do not experience the same substantial degradation of mechanical performance as their unsaturated counterparts upon prolonged exposure to air.

Molecular dynamics simulation and experimental study on the mechanical properties of PET nanocomposites filled with CaCO3, SiO2, and POE-g-GMA

Abstract This work investigated the mechanical properties of polyethylene terephthalate (PET) reinforced with calcium carbonate (CaCO3) and silica (SiO2) nanoparticles, respectively, and the improvement in toughness of the ternary system with the incorporation of graft-modified ethylene-1-octene copolymer (POE-g-GMA). PET nanocomposites were prepared by melt blending extrusion and injection molding. Molecular dynamics (MD) simulation was employed to construct models for binary system filled with nanoparticles and ternary system with the additional inclusion of POE-g-GMA elastomers. The results of mechanical property tests and MD simulation revealed that the binary system exhibited increased elastic modulus and tensile strength, mainly attributed to the effective reinforcement of rigid nanoparticles and the surface adsorption between nanoparticles and the PET matrix enhanced the interfacial interactions. CaCO3 indicated a more pronounced reinforcing effect, possibly due to the higher crystallinity of its composites. The incorporation of POE-g-GMA resulted in a significant improvement in impact strength and the elongation at break of PET nanocomposites. This enhancement in toughness is attributed to the elastomer’s ability to absorb a substantial amount of impact energy, while the elastic modulus is higher than that of pure PET.

Gadolinium oxide Nanoparticles Infusion in Heat-Cured Acrylic Denture Base Material: Impact on Glass Transition Temperature and Mechanical Strength Enhancement

Introduction: Nano dentistry has paved the way for advanced therapeutic opportunities in various dental disciplines, particularly in the improvement of oral health. One area of focus is the enhancement of mechanical properties of dental materials, such as acrylic resins commonly used in denture base materials. Various strategies, including chemical corrections and the addition of particles, have been explored to augment the mechanical qualities. This study investigates the impact of incorporating Gadolinium oxide nanoparticles into heat-cured acrylic denture materials. Materials and Methods: The denture base was processed using a standardized approach, with the addition of Gadolinium oxide nanoparticles during the monomer phase. A total of 120 specimens were fabricated. 30 specimens for each test using 10 specimens for each nanoparticle concentration (Control 0%, 1%, and 1,5% nanoparticles). The nanoparticles were dispersed using sonication to ensure uniform distribution. The study assessed properties such as glass transition temperature using a differential scanning calorimeter, impact strength and transverse strength utilizing an Instron universal testing machine, and surface roughness via profilometer measurements. Scanning electron microscope also utilized. One way ANOVA was used to determine the mean differences. Results: The study revealed significant improvements in glass transition temperature, impact strength, and transverse strength. The peak values were often seen in the 1.5% wt. group. Surface roughness, however, showed non-significant changes with nanoparticle additions, possibly due to the minimal involvement of nanoparticles on the outer surface. Conclusion: Incorporating Gadolinium oxide nanoparticles into heat-cured acrylic denture base materials demonstrated notable enhancements in key mechanical properties. The findings suggest that nanoparticle additions contribute to increased strength and rigidity, as evidenced by improvements in impact and transverse strength. However, surface roughness remained largely unaffected. This study contributes valuable insights into the potential benefits of nanotechnology in optimizing dental materials for improved clinical performance and patient outcomes.

Thermal, mechanical, electrical properties of poystyrene/poly (styrene-b-isobutylene-b-styrene/carbon nanotube nanocomposites

In this study, high impact polystyrene (HIPS) materials was prepared by using a styrenic elastomer (10, 20, 30 wt%) and carbon nanotube (CNT) (3, 5, 7, 10 phr) by melt blending technique as alternative to commercial HIPS including polybutadiene rubber. The poly (styrene- b-isobutylene- b-styrene) (SIBS) was used as thermoplastic elastomer with polystyrene (PS) to improve its poor impact resistance and CNT was added to PS/SIBS blend matrix to maintain its strength and stiffness. The modulus, tensile strength and toughness values of the blends decreased while those of impact resistance increased in comparison to neat PS. The impact strength of PS20SIBS blend containing 20 wt% SIBS was found to be approximately 530% higher than pure PS. The nanocomposites of the PS20SIBS exhibited a decrease in the size of SIBS particles with increasing CNT compared to PS20SIBS. This was ascribed to the increased viscosity of PS matrix via CNT filler, preventing the coalescence of the elastomer domains. Compared to the PS20SIS, its nanocomposites showed higher strength, modulus and toughness, but lower impact strength. The toughness of the nanocomposite containing 5 phr CNT (PS20SIBS-5CNT), increased by 117% while its creep deformation decreased by approximately 40%, in comparison with PS20SIBS blend. Although PS20SIBS-5CNT exhibited lower impact strength than the PS20SIBS blend due to the dispersion of smaller SIBS particles in the PS matrix, it still increased the impact strength of pure PS by 188%. The PS20SIBS-5CNT nanocomposite, which improved impact strength and creep resistance with optimal toughness and tensile modulus can be used as a novel HIPS material that tunes the hardness-toughness/impact balance effectively. Moreover, the same nanocomposite was found to reach the conductivity threshold by exhibiting 106 times lower electrical resistance in comparison with that containing 3 phr CNT, leading to a conductive filer network with 5 phr loading of the nanotubes into the system.

An Approach to Testing Antivandal Composite Materials as a Function of Their Thickness and Striker Shape-A Case Study.

Our research material comprised antivandal fire-retardant hybrid composites modified with inorganic and organic fillers intended for application in public transport vehicles. This paper presents an approach to studying their impact strength as a function of the composite thickness (3 to 6 mm) and striker shape (hemispherical, semicylindrical, wedge-shaped) used in the experimental stand. Group A composites, made of single fabric layers (n = 5), were thinner and their impact strength was lower by 73% than that for Group B composites made of double fabric layers. Study results show an almost threefold improvement in impact strength for a thickness increase of as little as 0.3 mm. Statistical analysis (the Shapiro-Wilk test, p > 0.05) did not show any significant differences in the quantitative evaluation of changes (n = 3) on the surface of the examined materials caused by impacts with strikers of different shapes. In turn, a linear correlation (Shapiro-Wilk test, W = 0.0857, p = 0.022) was found between impact strength and the thickness of the studied materials. It was observed that appropriate arrangement of fabrics and powder fillers can lead to a different distribution of forces and energy absorbed by the tested material. A lower impact strength was observed for the composite which had powder fillers in its composition, which caused the formation of microvoids in the structure of the material and thus led to a weakening in their strength properties. An effect of the placement of the glass fabric layer in the composite on the results was also observed. Moreover, SEM evaluation of the composites revealed their layered structure and the impregnation of woven fabrics with resin.

A Bio-Inspired Approach to Improve the Toughness of Brittle Bast Fibre-Reinforced Composites Using Cellulose Acetate Foils.

Bast fibre-reinforced plastics are characterised by good strength and stiffness but are often brittle due to the stiff and less ductile fibres. This study uses a biomimetic approach to improve impact strength. Based on the structure of the spicules of a deep-sea glass sponge, in which hard layers of bioglass alternate with soft layers of proteins, the toughness of kenaf/epoxy composites was significantly improved by a multilayer structure of kenaf and cellulose acetate (CA) foils as impact modifiers. Due to the alternating structure, cracks are deflected, and toughness is improved. One to five CA foils were stacked with kenaf layers and processed to composite plates with bio-based epoxy resin by compression moulding. Results have shown a significant improvement in toughness using CA foils due to increased crack propagation. The unnotched Charpy impact strength increased from 9.0 kJ/m2 of the pure kenaf/epoxy composite to 36.3 kJ/m2 for the sample containing five CA foils. The tensile and flexural strength ranged from 74 to 81 MPa and 112 to 125 MPa, respectively. The tensile modulus reached values between 9100 and 10,600 MPa, and the flexural modulus ranged between 7200 and 8100 MPa. The results demonstrate the successful implementation of an abstract transfer of biological role models to improve the toughness of brittle bast fibre-reinforced plastics.

Acrylonitrile‐styrene‐acrylate particles with different acrylonitrile contents for improving the toughness of poly(vinyl chloride) resin

AbstractPoly(butyl acrylate) grafted styrene and acrylonitrile copolymer (PBA‐g‐SAN, ASA) with core–shell structures were prepared by emulsion polymerization technology to improve the toughness of the poly(vinyl chloride) (PVC). The mechanical properties of the PVC/ASA blends were investigated. The notch impact strength of the PVC/ASA blend could reach 1200 J/m when the 13 phr ASA was added to the PVC. This was several times more than pure PVC resin. Scanning electron microscopy analysis results indicated that the improvement in impact strength of the PVC/ASA blend was attributed to shear yielding induced by ASA particles. Additionally, subtle changes in the ratio of monomers in the shell layer led to significant fluctuations in the mechanical properties of the composites. Dynamic mechanical analysis showed that the intermolecular interaction forces between ASA particles and PVC resins played a key role in improving the toughness of PVC/ASA blend.

Hemp fiber reinforced dual dynamic network vitrimer biocomposites with direct incorporation of amino silane

Natural fiber composites are inexpensive and renewable alternatives to traditional fiber reinforced polymers (FRPs). However, existing natural fiber composites primarily rely on petrochemical based thermosetting matrices, which are difficult to recycle due to their stable crosslinked network structures. To address this challenge, it is desirable to develop natural fiber composites with inherently recyclable biobased matrices. In this study, we developed a dual dynamic network vitrimer matrix from hempseed oil and limonene derivatives and demonstrated its application in hemp fiber reinforced composites. To improve the weak interface between hemp fiber and the polymer matrix, a common challenge in the realm of natural fiber composites, we directly incorporated amino silane into the vitrimer matrix. The amino silane participated in the polymer network, increasing the crosslink density and toughening the matrix, as evidenced by the significant improvement of impact strength from 3.5 kJ/m2 to 10.3 kJ/m2. Moreover, the incorporation of amino silane resulted in a lower water absorption by 11 % in a 7-day soaking for the composites, demonstrating improved fiber/matrix interfacial interaction. Furthermore, our biobased vitrimer matrix exhibits both imine and hydroxy-ester dynamic bonds, which enable the recycling of the biocomposite through a mild and cost-effective aminolysis process (100 °C, 3 h, ambient pressure). The decomposed polymer matrix was successfully reused as a polyol for polyurethane adhesives, and the surface morphology of recovered hemp fibers was analyzed and compared with that of the original fibers. These findings will help broaden the use of vitrimers for practical natural fiber composite applications, raise awareness of the problem of recycling natural fiber composite waste, and shed light on the interfacial challenge of natural fiber reinforced vitrimer composites.

Polyolefin Blends with Selectively Crosslinked Disperse Phase Based on Silane-Modified Polyethylene.

Polypropylene-based multiphase compositions with a disperse elastomer phase provide superior impact strength. Making this property indifferent to processing steps requires stabilization of the morphology of these materials. Various approaches have been tested over time, each of which shows limitations in terms of performance or applicability. Using polyethylene (PE) homo- and copolymers capable of silane-based crosslinking as modifiers was explored in the present study, which allows decoupling of the mixing and crosslinking processes. Commercial silane-copolymerized low-density PE (LD-PEX) from a high-pressure process and silane-grafted high-density PE (HD-PEX) were studied as impact modifiers for different types of PP copolymers, including non-modified reference PE grades, LDPE and HDPE. Blends based on ethylene-propylene random copolymers (PPR) and based on impact- (PPI) and random-impact (PPRI) copolymers show improvements of the stiffness-impact balance; however, to different degrees. While the absolute softest and most ductile compositions are achieved with the already soft PPRI copolymer base, the strongest relative effects are found for the PPR based blends. Modifiers with lower density are clearly superior in the toughening effect, with the LD-PEX including acrylate as second comonomer sticking out due to its glass transition around -40 °C. The impact strength improvement found in most compositions (except at very high content) results, however, not from the expected phase stabilization. For comparable systems, particle sizes are normally higher with crosslinking, probably because the process already starts during mixing. Thermoplastic processability could be retained in all cases, but the drop in melt flow rate limits the practical applicability of such systems.

Mechanical, morphological, and numerical evaluation of biocompatible ultra‐high molecular weight polyethylene/nano‐zeolite nanocomposites

AbstractThe incorporation of bio‐friendly nano‐zeolite (NZ) into ultra‐high molecular weight polyethylene (UHMWPE), renowned for its exceptional biocompatibility, presents an intriguing pathway for robust structural biomedical applications. This study aimed to investigate the influence of NZ integration on the tensile and impact properties of UHMWPE/NZ nanocomposites through experimental and morphological assessments. The morphology examinations primarily entailed particle distribution, clustering extent, and the primary toughening response induced by fillers under impact loading. Fourier transform infrared spectroscopy (FTIR) was utilized to investigate the bonding characteristics between NZ and UHMWPE within the nanocomposites. Moreover, differential scanning calorimetry (DSC) was employed to examine alterations in the crystalline structure of the nanocomposites, revealing an increase of up to 9% in crystallinity () following the incorporation of NZ. Tensile tests demonstrated significant improvements, with a 45% increase in tensile modulus and a 14% increment in strength upon the inclusion of NZ. Impact toughness consistently showed enhancements of up to 24%. The improved impact strength was attributed to the extensive partial particle‐induced debonding and subsequent release of plastic constraints within the matrix. The micro‐mechanisms responsible for nanoparticle‐triggered toughening were further investigated using super‐magnified images from impact‐fractured SEM micrographs, and various impact toughening mechanisms were observed, classified, and discussed in the UHMWPE/NZ nanocomposites. Various analytical solutions were employed to predict the elastic modulus and tensile strength of nanocomposites. Subsequently, the results were compared to experimental data, and any discrepancies were thoroughly justified.Highlights The mechanical traits of UHMWPE/nano‐zeolite nanocomposites were explored. Tensile and impact strength increased up to 14% and 24% with NZ addition. Morphological inspections were conducted to assess filler‐induced debonding. Toughening mechanisms were assessed through super‐magnified SEM micrographs. Micromechanical models were used to predict the tensile modulus and strength.

Development of a micro-scale hybridized yarn structure from recycled carbon, aramid and polyamide 6 staple fibers for thermoplastic composites with improved impact strength

The aim of this research is to improve the impact strength of thermoplastic composites manufactured from recycled carbon fiber (rCF). For this purpose, the development of a novel multi-material, micro-scale hybridized and low-cost hybrid yarn by blending aramid fibers with rCF and polyamide 6 (PA 6) fibers through the processing route of carding, drawing and flyer spinning is reported in this paper. In addition, two other hybrid yarns were produced from rCF/PA 6 and aramid/PA 6 for comparison with the multi-material rCF/aramid/PA 6 hybrid yarn. Finally, the tensile, flexural and impact properties of composites based on the developed rCF/aramid/PA 6 multi-material hybrid yarn were compared with those of composites reinforced only with rCF and aramid fiber. The results of the Charpy impact test showed that the inclusion of 24 volume percentage aramid fiber increased the impact strength by 70% compared to the composite reinforced with rCF alone. The multi-material hybrid yarn consisting of rCF/aramid/PA 6 fibers shows good potential for designing a hybrid composite with tailored tensile, flexural and impact resistant properties.

Electromagnetic Shielding Effectiveness and Impact Test Performance of Carbon Fiber Reinforced Polymer Composites with Hematite and Goethite

AbstractCarbon fibers (CFs) are versatile materials widely employed in carbon fiber‐reinforced polymer (CFRP) composites, known for their superior mechanical properties and electromagnetic interference (EMI) shielding capabilities. This study focuses on the successful production of 2‐layer CFRP composites reinforced with hematite (Fe2O3) particles, in two different sizes (≈44 µm (325 mesh) and 50 nm), and goethite (FeO(OH)), utilizing the hand lay‐up method. The investigation encompasses EMI shielding effectiveness (SE) within a frequency range of 700 to 6000 MHz, and the drop‐impact strength resistance properties (under a 6 J load). Results indicate that the highest EMI SE value, 60.19 dB at 5900 MHz, is achieved with 5 wt.% goethite reinforcements, while with a reduction in drop‐impact strength. For hematite‐reinforced composites, the highest EMI SE, measuring 57.85 dB at 5800 MHz, is observed for samples containing 15 wt.% hematite particles with a size of 50 nm, which exhibited an overall improvement in impact strength compared to non‐reinforced samples. This research highlights the potential of these CFRP composites for EMI shielding applications, with considerations for their impact on mechanical properties, providing valuable insights for applications demanding both EMI protection and structural integrity.

A green flame retardant coating based on one-step aqueous complexation of phytic acid and urea for fabrication of lightweight and high toughness flame retardant EPS insulation board

Green flame retardants have drawn much attention because of their environmental friendliness. But for the high flame retardancy of flammable polymers, most existing green flame retardants are unsatisfactory, even the flame-retardant process can not achieve high efficiency and environmental protection. In this work, flame retardants and flame-retardant process are addressed in a two-pronged approach. An eco-friendly bio-based synergistic flame retardant (PAU) was synthesized based on phytic acid (PA) and urea (U) through simple complexation assembly in water. The designed flame retardant coating can be directly coated on the surface of any topological shape with polydopamine as an adhesive. Flame retardant expandable polystyrene (EPS-PAU) with light weight and high toughness is prepared with the designed PAU flame-retardant coating. The coated EPS plates exhibit V-0 UL-94 rating and 42.0 % of limited oxygen index and excellent smoke suppression. Moreover, the density of EPS-PAU is slightly increased only by 2.27 % on the basis of the neat EPS, and the hard shell formed using PDA as an adhesive layer is beneficial for the improvement of impact strength. This novel biomass-based PAU system provides a promising strategy for manufacturing polymer products with excellent flame retardancy, smoke inhibition and light weight.

Texture and damage evolution in additively manufactured 18 %Ni-M350 maraging steel under dynamic impact loading: Processing parameters and heat treatment effects

The mechanical and microstructural responses of 18 % Ni M350 maraging steel produced by additive manufacturing (AM) using the direct energy deposition (DED) laser process under impact loading are investigated. The material is manufactured using low and high energy area density (EAD) to identify the influence of AM processing parameters on the impact strength, microstructural, and texture evolution during deformation. In addition to the as-built (AB) state, maraging steel samples subjected to solutionizing and aging heat treatment (HT) are also investigated. Electron backscatter diffraction (EBSD) is used to characterize texture evolution under impact loading. The test results reveal that the low-EAD material exhibits the greatest impact strength for the applied strain rates that ranged from 200 to 3300 s−1 in its as-built state. This finding is attributed to the high local misorientation that is closely correlated with the dense dislocation network generated as a result of the rapid cooling process. The activation of a new slip systems {112}〈111¯〉 and {123}〈111¯〉 is observed after deformation at high strain rates in the as-built material. A higher degree of new slip system activation in low-EAD samples suggests a higher susceptibility to the initiation of an adiabatic shear band (ASB). The effects of processing parameters on impact strength, strain, and propensity to defects are eliminated by heat treatment. The improvement in impact strength of the steel materials after heat treatment can be attributed to the dominance of precipitate-dislocation interactions as the primary strengthening mechanism. Furthermore, heat-treated materials exhibit the highest susceptibility to deformation-induced defects, such as adiabatic shear bands and fracture.

Thermosetting polymer composites: Manufacturing and properties study

Abstract In the proposed study, TiC is used in different sizes (i.e., 70–150 nm and 200–250 μm) and different ratios (e.g., 0, 10, 20, and 30 wt%) to reinforce the epoxy matrix. Micro- or nano-epoxy–TiC mixtures are poured into molds that have been prepared. The results obtained show a significant improvement in hardness, impact, creep, and tensile strength when the hard particles of nano- and micro-TiC are increased up to 20 wt%. This is due to the good dispersion of the TiC powder with minimal agglomeration and air bubbles. In addition, the results obtained show a decrease in hardness, impact, creep, and tensile strength when the ratio of the hard particles of nano- and micro-TiC is increased to 30 wt% due to agglomeration and air bubbles, which create a path for cracks to propagate. The results of the hardness, impact, creep, and tensile strength tests when 20 wt% nano-TiC composite specimens are used are 22.4, 67.55 J·m−2, 0.0132, and 34.7 MPa, respectively. These results show higher values than other composite specimens. A pin-on-disc wear testing process with various sliding lengths is used to analyze wear behavior. The maximum wear resistance of the 10 wt% of micro-epoxy–TiC composites is found at a load of 5 N and a 100 m sliding distance. Optical microscopy shows small scratches on the 10 wt% micro-epoxy–TiC composite specimens in comparison with the 10 wt% nano-epoxy–TiC composites at a load of 5 N and a 200 m sliding distance.

Mechanical Properties' Strengthening of Photosensitive 3D Resin in Lithography Technology Using Acrylated Natural Rubber.

Acrylated natural rubber (ANR) with various acrylate contents (0.0-3.5 mol%) was prepared from natural rubber as a raw material and then incorporated with commercial 3D resin to fabricate specimens using digital light processing. As a result, the utilization of ANR with 1.5 mol% acrylate content could provide the maximum improvement in stretchability and impact strength, approximately 155% and 221%, respectively, over using pure 3D resin, without significant deterioration of tensile modulus and mechanical strength. According to evidence from a scanning electron microscope, this might be due to the partial interaction between the dispersed small rubber particles and the resin matrix. Additionally, the glass-transition temperature of the 3D-printed sample shifted to a lower temperature by introducing a higher acrylate content in the ANR. Therefore, this work might offer a practical way to effectively enhance the properties of the fundamental commercial 3D resin and broaden its applications. It also makes it possible to use natural rubber as a bio-based material in light-based 3D printing.

Enset Fiber-Reinforced Polylactic Acid-Based Biocomposites for High-Performance Application

In recent years, there has been growing interest in using plant fibers to reinforce materials in modern manufacturing. This study focuses on the development of a novel biocomposite made from an enset fiber (EF) and polylactic acid (PLA) matrix using compression molding at a hot-pressing temperature of 170 °C and pressure of 7 MPa for 7 min. Before preparing the biocomposites, the fibers were chemically modified with different concentrations of sodium hydroxide (NaOH) and cut into shorter fibers with a 40 mm average length in size. Then, the extent of modifications on the mechanical properties, dynamic mechanical behavior, morphology, and water absorption were investigated. The tensile, flexural, and Charpy impact tests were carried out to evaluate the mechanical properties of the samples as per ASTM standards. Moreover, dynamic mechanical analysis (DMA) and the water absorbency of the biocomposites were investigated, and the results were graphically shown and explained. The results indicate that the biocomposite treated with 5% NaOH exhibited significant improvements in tensile strength, flexural strength, and impact strength compared to the untreated composite. The tensile modulus and flexural modulus of 5% NaOH-modified enset fiber biocomposite were also enhanced by 55.8% and 70.3% compared to untreated enset fiber biocomposite. The highest tensile strength, flexural strength, and impact strength found for the PLA composite reinforced by EF treated with 5% w/v NaOH solution were 20.16 MPa, 30.21 MPa, and 12.02 kJ/m2, respectively. In general, the modification of natural fibers improves adhesion at the interface and therefore decreases the water absorption and improves the dynamic mechanical properties of biocomposites.