Improvement In Impact Strength Research Articles

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.

The search for rigid, tough polyesters with high T g - renewable aromatic polyesters with high isosorbide content.

Renewable polyesters with a good balance between impact strength and elastic modulus (stiffness) are not very common, especially when combined with high glass transition temperature (T g). Achieving such high performance properties would enable the substitution of high performance polymers like ABS and polycarbonate with chemically recyclable polyesters from bio-based or recycled sources. One of the challenges in developing these materials is to select the right composition of the right monomers/comonomer ratios and making these materials with high molecular weight, which can be challenging since some of the most promising rigid diols, such as isosorbide, are unreactive. This study comprises aromatic polyesters from (potentially) renewable monomers, using bio-based isosorbide as a means to increase their T g and to inhibit their crystallization, while using flexible co-diols to improve impact strength. To incorporate a high amount of isosorbide into the targeted polyesters, we used the synthesis method with reactive phenolic solvents previously developed in our group. The selected compositions display high T g's (>90 °C) and high tensile modulus (>1850 MPa). We show that more polar monomers such as the stiffer 2,5-furandicarboxylic acid (FDCA) and diethylene glycol cause high stiffness but decreased impact strength (<5 kJ m-2). Combining terephthalic acid and isosorbide with more flexible diols like 1,4-butanediol, 1,4-cyclohexanedimethanol (CHDM) and 1,3-propanediol provides a better balance, including the combination of high tensile modulus (>1850 MPa) and high impact strength (>10 kJ m-2).

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.

Flame retardant, strong and tough, low dielectric epoxy thermoset enabled by a novel bi-DOPO type epoxy with aggregation-induced emission

Multifunctional epoxy resins with excellent flame retardancy, high strength, high toughness, low dielectric loss and strong fluorescence show great potentials in electrical/electronic applications; however, simultaneously achieving those goals are difficult. To address those challenges, an epoxy resin with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) pendant group and flexible aliphatic spacer (DOPOEP) was developed. V-0 rating in UL-94 test and LOI of 33.1% are achieved at only 0.45 wt% phosphorus loading, benefitting from the flame retardant mechanism in gas and condensed phase. Compared with neat DGEBA, the cured epoxy with 10 wt% DOPOEP shows 13.4% and 37.6% improvements in tensile strength and impact strength, respectively; in addition, the tensile strength of the cured epoxy with 20 wt% DOPOEP is as high as 102.2 MPa, a 35.3% increase, without compromising toughness. The strengthening effects of DOPOEP derive from π-π stacking and hydrogen bonding, and the improved toughness is due to the flexible aliphatic spacer and reduced crosslinking density. Meanwhile, free volume reduction was observed after introducing DOPOEP, which is responsible for the improved modulus. DOPOEP addition also lowers the hydroxyl group concentration, leading to lower dielectric constant and dielectric loss tangent. Moreover, the aggregation-induced emission behavior of DOPOEP was reported, and its application in anti-counterfeiting field was explored. In air, the fluorescence of DOPOEP-containing thermoset steadily diminishes with increasing temperature, however the fluorescence changing trend is complex in vacuum. Besides, the fluorescence of DOPOEP is effective in the visual detection of defects and flaws in cured products. This work provides a new direction for developing high-performance epoxy with multifunction.

Experimental Study on Concrete by Adding Polyester Fibres

Abstract There are increased innovations in the field of concrete because there are endless opportunities for innovative materials, techniques, applications, and design. Today’s construction industry is looking for cost-effective materials to improve the strength of concrete structures. As a result, an attempt has been made in the current research to investigate the impact of adding polyester fibres (Recron 3s) to concrete. Fibres improve concrete's tensile and flexural strength, fatigue properties, durability, shrinkage properties, impact and erosion resistance, and serviceability. Polyester fibres (Recron 3s) are micro fibres; they contribute to enhancing the resistance of concrete to shrinkage and cracking and also help to improve mechanical properties such as the flexural / split tensile and transverse strength of concrete along with improvements in abrasion and impact strength. An experimental study was done using a M30 mix design. Polyester fibres (Recron 3s) were used in the concrete with varying dosage rates of 0.50 kgs / cu.m – 2.00 kgs / cu.m. This study describes the enhancement in the strength of the M30 grade mix concrete by the addition of polyester fibres (Recron 3s) in the proportions of 0.5, 1, 1.5, 2.0kg/cu.m, and M30 concrete with varying dosages of the polyester fibres (Recron 3s) were mixed and cast.

INVESTIGATING PRINTABILITY AND MECHANICAL PERFORMANCE OF 3D PRINTED RECYCLED PET WITH PLA AND TPU HYBRID ADDITIVES

This paper investigates the printability and mechanical performance of 3D printed recycled PET (rPET) filaments with the incorporation of PLA and TPU blend additives. The study focuses on evaluating the tensile, flexural, and impact properties of the resulting hybrid blends. Tensile testing revealed that the neat rPET specimens exhibited average maximum tensile strength of 51.4 MPa and a tensile elasticity modulus of 3.63 GPa. The addition of PLA and TPU additives slightly reduced the tensile strength and modulus. Regarding flexural properties, the rPET specimens demonstrated an average maximum flexural stress of 43.4 MPa, indicating their ability to withstand bending forces without significant deformation. The addition of the hybrid PLA and TPU additives led to a slight reduction in flexural performance. However, the specimens still exhibited acceptable flexural strength and modulus. Furthermore, the impact test results showed a significant improvement in impact strength for the hybrid blend, with the TPU/PLA (rPET blend) exhibiting a remarkable increase (%187 and 36%) compared to the commercial and neat rPET specimens, respectively. These findings suggest that the hybrid combination of PLA and TPU additives contributes to the microstructural integrity and printability of 3D printed objects made from recycled PET filaments, thereby contributing to the advancement of sustainable manufacturing practices.

Tailoring PLA/ABS Blends Compatibilized with SEBS-g-MA through Annealing Heat Treatment.

In this work, blends based on poly (lactic acid) (PLA)/acrylonitrile-butadiene-styrene (ABS) compatibilized with maleic anhydride-grafted (SEBS-g-MA) were prepared in a co-rotational twin-screw extruder by varying the concentrations of the compatibilizing agent. The influence of the compatibilizing agent on the morphology, mechanical, thermal, thermomechanical, and rheological properties of the prepared materials was analyzed. The effect of annealing on the properties of the blends was also investigated using injection-molded samples. The X-ray diffraction (XRD) results proved that the increments in crystallinity were an effect of annealing in the PLA/ABS/SEBS-g-MA blends, resonating at higher heat deflection temperatures (HDTs). The impact strength of the PLA/ABS blends compatibilized with 10 wt% SEBS-g-MA was significantly increased when compared to the PLA/ABS blends. However, the hardness and elastic modulus of the blends decreased when compared to neat PLA. The refined morphology shown in the scanning electron microscopy (SEM) analyses corroborated the improved impact strength promoted by SEBS-g-MA. The torque rheometer degradation study also supported the increased compatibility between SEBS-g-MA, PLA, and ABS. The TGA results show that the PLA/ABS and PLA/ABS/SEBS-g-MA blends are more thermally stable than the neat PLA polymer at higher temperatures. The results showed that the ideal composition is the heat-treated PLA/ABS/SEBS-g-MA (60/30/10 wt%), given the high impact strength and HDT results. The results of this work in terms of mechanical improvement with the use of compatibilizers and annealing suggest that the PLA/ABS/SEBS-g-MA system can be used in the production of 3D-printing filaments.

Jute woven fabric modified by phosphorus‐containing organosilicon compound reinforced flame retardant polylactic acid composites with enhanced flame retardant and mechanical properties

AbstractBalancing the flame retardant properties and mechanical performance is important for flame retardant composites. In this research, the polylactic acid (PLA)/fiber composite is prepared by treating jute woven fabric with phosphorus‐containing organosilicon compound (PCOC) and adding intumescent flame retardant (IFR) to PLA using a film‐stacking procedure, which is named flame retardant PLA (FRPLA)/PC‐F. The flame retardancy and mechanical properties of PLA/fiber composites were studied and analyzed. Mechanical/flame retardant index (M/F index) was developed to compare the comprehensive properties of the composites. The limited oxygen index (LOI) test results show the LOI value of FRPLA/PC‐F reaches 34.1%, 14.1% higher than untreated PLA/fiber composite (PLA/F). In the cone calorimeter test, the pk‐heat release rate (HRR) value of FRLA/PC‐F decreases from 549 to 388 kW/m2 compared with PLA/F. In addition, the char yield of FRPLA/PC‐F increases from 1.9% (PLA/F) to 18.6%. The scanning electron microscope images of the char yield for FRPLA/PC‐F obtained from cone calorimetry test shows a continuous network structure with the fibrous skeleton completely wrapping by the dense and uniform char layer, which plays a barrier effect that inhibits the release of volatile substance and the transfer of heat. Meanwhile, FRPLA/PC‐F exhibits 28% and 19% improvement in tensile strength and impact strength compared with PLA/F due to the boost of interfacial adhesion between fiber and PLA. The M/F index of FRPLA/PC‐F is 1.15, which is the highest among all the composites, proving the best comprehensive properties and practical applicability. The results in this manuscript above make a great development, which is attractive in the design of PLA/fiber composites with great comprehensive performance.