Butadiene Styrene Research Articles

From e-waste to living space: Flame retardants contaminating household items add to concern about plastic recycling

Brominated flame retardants (BFRs) and organophosphate flame retardants (OPFRs) are commonly used in electric and electronic products in high concentrations to prevent or retard fire. Health concerns related to flame retardants (FRs) include carcinogenicity, endocrine disruption, neurotoxicity, and reproductive and developmental toxicity. Globally, a lack of transparency related to chemicals in products and limited restrictions on use of FRs in electronics have led to widespread use and dissemination of harmful FRs. Despite the lack of transparency and restrictions, plastics from electronics are often recycled and can be incorporated in household items that do not require flame retardancy, resulting in potentially high and unnecessary exposure. This study sought to determine whether black plastic household products sold on the U.S. market contained emerging and phased-out FRs and whether polymer type was predictive of contamination. A total of 203 products were screened for bromine (Br), and products containing >50 ppm Br were analyzed for BFRs, OPFRs, and plastic polymers (e.g. acrylonitrile butadiene styrene, high impact polystyrene, polypropylene). FRs were found in 85% of analyzed products, with total FR concentrations ranging up to 22,800 mg/kg. FRs detected include the restricted compound deca-BDE, which was used widely in electronics casings, as well as its replacements decabromodiphenyl ethane (DBDPE) and 2,4,6-Tris(2,4,6-tribromophenoxy)-1,3,5-triazine (TBPP-TAZ) along with associated compound 2,4,6-tribromophenol (2,4,6-TBP), recently detected in breast milk. Plastic typically used in electronics (styrene-based) contained significantly higher levels of ∑FRs than plastics less typically used for electronics (polypropylene and nylon). Estimation of exposure to BDE-209 from contaminated kitchen utensils indicated users would have a median intake of 34,700 ng/day, exceeding estimates for intake from dust and diet. The detection of FRs in collected household products indicates that recycling, without the necessary transparency and restrictions to ensure safety, is resulting in unexpected exposure to toxic flame retardants in household items.

Enhanced Gas Barrier and Mechanical Properties of Styrene-Butadiene Rubber Composites by Incorporating Electrostatic Self-Assembled Graphene Oxide @ Layered Double Hydroxide Hybrids.

Rubber composites with a high gas barrier and mechanical properties have received considerable attention due to their potential applications. Constructing complex filler networks in a rubber matrix is an effective strategy to simultaneously enhance the gas barrier and mechanical properties. In this work, graphene oxide layered double hydroxide (GO@LDHs) hybrids were obtained by the electrostatic self-assembly method. A unique interspersed and isolated structure was formed in GO@LDHs hybrids due to the chemical interactions between the functional groups on GO sheets and the metal cations on LDH layers. Subsequently, the GO@LDHs hybrids were incorporated into a styrene-butadiene rubber (SBR) matrix using a green latex compounding method. The results showed that the GO@LDHs hybrids were uniformly embedded in the SBR matrix, constructing an overlapped filler network and forming physical bonding points that reduced the free volume of the composites. The electrostatic interactions between GO@LDHs hybrids facilitated energy dissipation during stretching, thereby improving the mechanical performance of the rubber composites. More importantly, the N2 gas permeability and fracture toughness of GO@LDHs/SBR composites decreased by 52.2% and increased by 845%, respectively, compared to those of a pure SBR matrix. The construction of GO@LDHs hybrids offers new insights for designing rubber composites with a high gas barrier and mechanical properties.

Assessment of various polymeric sulphur as soft bitumen improver for pavement applications

ABSTRACT In this study, five polymeric sulphurs are utilised, including polymeric sulphur based on both aliphatic copolymers and styrene copolymers, namely PS1 to PS5 correlated to amorphous poly alpha olefins (APAO) PS1, olefin residues from MAC carpet company PS2, Ethylene Vinyl Acetate (EVA) copolymer PS3, Styrene Butadiene Styrene (SBS) copolymer PS4 and Dicyclopentadiene monomer (DCPD) PS5. The five polymeric sulphur compounds were mixed by 25wt% with soft bitumen penetration grade (80/100) to produce five sulphur-extended asphalt binders, namely SEA1, SEA2, SEA3, SEA4, and SEA5. The physical properties, including softening point, viscosity, and penetration, are examined to characterise the consistency of SEA binder. The dynamic mechanical behaviour such as complex modulus, temperature sweep, and stress relaxation test was investigated for SEA binder and compared with a reference soft bitumen (Blank) using a dynamic mechanical analyzer (DMA). It is concluded that polymeric sulphur based on styrene compounds SEA2 and SEA4 binders have the highest resistance against cracking of the pavement at low temperatures according to penetration index readings, and have the least permanent (plastic) deformation at high temperatures according to temperature sweep from DMA data. It is noticed that SEA5 binder has a negative effect on the performance of soft bitumen.

Enhancing toughness in cement-based composites: Unraveling the composite effect mechanisms of polymers and fibers through physic testing and molecular dynamics simulations

To reveal the toughening mechanism of polymers and fibers in composite applications, a combination of physical tests (uniaxial compression, flexural fracture, single fiber pull-out, scanning electron microscopy, and X-ray diffraction (XRD)) and molecular dynamics simulations have been carried out. Three polymers, i.e. ethylene-vinyl acetate copolymer (EVA), styrene-acrylate copolymer (SAE), and styrene-butadiene copolymer (SB), and two fibers, i.e. polypropylene fiber (PP) and polyvinyl alcohol fiber (PVA) are considered. Their composite effect mechanisms are explained in the viewpoint of three scales. At the macro-scale, the pull-out tests of single fiber show that the polymer increased the equivalent bond strength between the fiber and the mortar matrix. At micro-scale, it was observed from the SEM experiments that the fiber and polymer film inhibited the crack extension at different scales, besides the polymer could absorb on the fiber surface to improve the interfacial transition zone (ITZ) density around the fiber and increase the roughness of the fiber surface. At nano-scale, MD simulations demonstrate that three polymers facilitated the bond strength between PP fiber and C–S–H at the nano-scale, mainly because of the formation of Ca–O coordination bond and H-bonds between the polymers and C–S–H, and the presence of van der Waals forces between the polymers and PP fiber. However, SAE facilitated the bonding between the PVA fibers and the C–S–H, which originated from the coordination bonds formed between Ca ions on the surface of SAE and O atoms in PVA. In addition, the large number of H-bonds formed between SAE and PVA.

Potential of Non-Contact Dynamic Response Measurements for Predicting Small Size or Hidden Damages in Highly Damped Structures.

Vibration-based structural health monitoring (SHM) is essential for evaluating structural integrity. Traditional methods using contact vibration sensors like accelerometers have limitations in accessibility, coverage, and impact on structural dynamics. Recent digital advancements offer new solutions through high-speed camera-based measurements. This study explores how camera settings (speed and resolution) influence the accuracy of dynamic response measurements for detecting small cracks in damped cantilever beams. Different beam thicknesses affect damping, altering dynamic response parameters such as frequency and amplitude, which are crucial for damage quantification. Experiments were conducted on 3D-printed Acrylonitrile Butadiene Styrene (ABS) cantilever beams with varying crack depth ratios from 0% to 60% of the beam thickness. The study utilised the Canny edge detection technique and Fast Fourier Transform to analyse vibration behaviour captured by cameras at different settings. The results show an optimal set of camera resolutions and frame rates for accurately capturing dynamic responses. Empirical models based on four image resolutions were validated against experimental data, achieving over 98% accuracy for predicting the natural frequency and around 90% for resonance amplitude. The optimal frame rate for measuring natural frequency and amplitude was found to be 2.4 times the beam's natural frequency. The findings provide a method for damage assessment by establishing a relationship between crack depth, beam thickness, and damping ratio.

Closed-loop circular economy in ‘upcycled’ acrylonitrile–butadiene–styrene vitrimer

Today, the issue of plastic waste pollution has reached unprecedented levels. The increasing production of plastics, combined with a decreasing rate of recycling, has significantly worsened this problem in recent years. While a wide range of plastics are manufactured, thermoplastics are a type that can be recycled relatively easily. However, recycled thermoplastics often have lower mechanical properties compared to new ones. Considering this challenge, making thermoplastics recyclable could revolutionize the recycling process and represent a major advancement towards establishing a circular economy for plastics. In this study, virgin acrylonitrile–butadiene–styrene (ABS) was transformed into a vitrimer through reactive melt extrusion using a bio-derived crosslinker containing dynamic imine linkages. This crosslinker results in a dynamic network, in the melt, as observed from the higher gel fraction and imparts recyclability to the resulting ABS vitrimer, which exhibits higher yield strength (by 15 %) and Young’s modulus (by 19 %). Remarkably, the mechanical and thermal properties of the vitrimer remain largely unchanged even after undergoing five cycles of reprocessing. In addition, the resulting vitrimer is dimensionally stable as inferred from creep studies and shows rapid stress relaxation at higher temperature following Arrhenius behaviour. The electron paramagnetic resonance (EPR) spectra were captured at room temperature for both ABS and its vitrimer. The difference in singlet band intensities in the spectra begins to suggest that the vitrimer is more stable post multiple recycling. While this research focused on virgin ABS, the approach outlined in the study has the potential to be applied to post-consumer recycled (PCR) ABS. This could introduce recyclability to PCR ABS and pave the way for a closed-loop circular economy for ABS plastics.

Experimental and Analytical Evaluation to Strengthened R.C Beams Using Ferrocement Under Torsion

The safety of structures around the globe represents a significant and pressing concern, underscoring the urgent need for the development and implementation of effective rehabilitation methods to ensure their continued functionality. Ferrocement has emerged as a durable method for the restoration of reinforced concrete (RC) structures, demonstrating resilience and versatility in addressing structural damage. A substantial body of research has been conducted to examine the mechanical properties of ferrocement, with a particular focus on its efficacy in reinforcing beams against a range of forces. In light of the limited understanding of the factors affecting the torsional strength of ferrocement-wrapped beams, it is imperative to conduct experimental investigations. The objective of this study is to evaluate and compare the torsional strength, angle of twist and crack development of different wrapping types using both analytical analysis and experimental data. The findings indicate that three-sided wrapping is an effective method for enhancing torsional behaviour, as evidenced by both experimental and analytical results. Furthermore, the utilization of styrene-butadiene rubber (SBR) as a connecting material has been demonstrated to be an effective method for maintaining cohesion across reinforced beams.

From Waste to Styrene-Butadiene (SBR) Reuse: Developing PP/SBR/SEP Mixtures with Carbon Nanotubes for Antistatic Application.

Styrene-butadiene rubber (SBR) waste from the shoe industry was repurposed to produce polypropylene (PP)-based compounds, with the aim of evaluating their antistatic potential. Styrene-ethylene-propylene (SEP) was added as a compatibilizing agent, while carbon nanotubes (MWCNT) were incorporated as a conductive nanofiller. The polymer compounds were processed in an internal mixer, and injection molded. The properties evaluated included torque rheometry, melt flow index (MFI), impact strength, tensile strength, Shore D hardness, electrical conductivity, heat deflection temperature (HDT), and differential scanning calorimetry (DSC), along with scanning electron microscopy (SEM) for morphology analysis. The production of the PP/SBR/SEP (60/30/10 wt%) compound resulted in a ductile material, enhancing impact strength and elongation at break to 161.2% and 165.2%, respectively, compared to pure PP. The addition of SEP improved the compatibility of the PP/SBR system, leading to an increase in the torque curve and a reduction in the MFI. Furthermore, the SBR/SEP combination in PP accelerated the crystallization process and increased the degree of crystallinity, suggesting a nucleating effect. Carbon nanotubes, in concentrations ranging from 0.5 to 2 phr (parts per hundred resin), were added to the PP/SBR/SEP system. Only the PP/SBR/SEP/MWCNT compound with 2 phr of MWCNT was suitable for antistatic applications, exhibiting an electrical conductivity of 4.52 × 10-07 S/cm. This was due to the greater distribution of MWCNT in the PP matrix, as demonstrated by SEM. In addition, remains tough at room temperature, with a 166% increase in impact strength compared to PP. However, there was a reduction in elastic modulus, tensile strength, Shore D hardness, and HDT due to increased flexibility. SBR waste can be reintegrated into the production chain to produce antistatic polymeric compounds, obtaining a tough material at room temperature.

Molecular dynamics simulation of interfacial interaction mechanisms between ground tire rubber and styrene-butadiene rubber enhanced by nanomaterial incorporation

The recycling of ground tire rubber (GTR) is an effective method for addressing black pollution. In this study, we investigated and compared the effects of acidic oxidation treatments and different nanomaterial contents on the interfacial properties of styrene-butadiene rubber (SBR) and GTR. Molecular models of GTR modified by acidic oxidation and nanomaterials, as well as SBR, were established. The interfacial interaction mechanisms between SBR and GTR were studied through tensile and shear behaviors. The results indicated that the properties of SBR-GTR interface were enhanced through acidic oxidation and nanomaterial modification, with the latter demonstrating superior advantages in augmenting the interfacial strength. Specifically, the addition of a carbon nanotube and graphene increased the interfacial cohesion strength by 55.12 % and 82.93 %, and the interfacial shear strength by 29.87 % and 43.05 %, respectively. Moreover, graphene exhibited superior performance in enhancing interfacial interactions compared to carbon nanotubes and increasing the nanomaterial content did not positively impact the improvement of interfacial properties. The interfacial properties of SBR and GTR were quantitatively analyzed using molecular dynamic (MD) simulations. This study provides a theoretical foundation for enhancing the mechanical properties of recycled rubber by using nanomaterials, thereby guiding the experimental preparation of recycled rubber.

Recognition and Characterization of Nanoscale Phases: Modulus Mapping of Asphalt Film in Pavement Mixture Cores.

The objective of this study is to recognize and characterize the nanoscale phase modulus mapping of the asphalt film in pavement mixture cores using atomic force microscopy quantitative nanomechanical technology. The pavement core samples from the upper and middle layers of four highways and laboratory samples were taken as the research object. The phase modulus-macro property correlation of recovered asphalt was analyzed using mathematical statistics. The results showed that the pavement core samples had more significant multi-phase and diversified phase characteristics compared to lab samples. This indicated that the asphalt in the pavement core had an obvious phase separation phenomenon due to aging. The phase modulus of each sample was distributed across a relatively wide numerical range, and there were also many numerical points with large fluctuations. Especially for the mixture sample containing SBS (Styrene-Butadiene-Styrene)-modified asphalt, the phase modulus distribution mappings presented a multi-peak phenomenon. Hence, considering the distribution characteristics of the data, the box plot method was introduced. Compared with quantified results from laboratory samples, the phase modulus of SBS-modified asphalt increased by 0.96 times, 1.18 times and 1.15 times, and that of base asphalt increased by 0.59 times, 0.56 times, 0.42 times, 1.24 times and 0.39 times, respectively. This indicates that the aging degree of asphalt in the upper layer was generally greater than that of the asphalt in the middle layer and that there was an aging gradient in the direction of pavement depth. All points were within the 95% confidence band in terms of correlation fitting, indicating a better fitting effect between phase modulus and complex shear modulus, as well as between phase modulus and penetration. This research provides innovative ideas for future multi-scale numerical simulation and cross-scale performance model development of asphalt binders.

Toxicological mechanisms and molecular impacts of tire particles and antibiotics on zebrafish

Tire microplastics (TMPs) and antibiotics are emerging pollutants that widely exist in water environments. The coexistence of these pollutants poses severe threats to aquatic organisms. However, the toxicity characteristics and key molecular factors of the combined exposure to TMPs in aquatic organisms remain unknown. Therefore, the joint toxicity of styrene–butadiene rubber TMPs (SBR-TMPs) and 32 antibiotics (macrolides, fluoroquinolones, β-lactams, sulfonamides, tetracyclines, nitroimidazoles, highly toxic antibiotics, high-content antibiotics, and common antibiotics) in zebrafish was investigated using a full factorial design, molecular docking, and molecular dynamics simulation. Sixty-four combinations of antibiotics were designed to investigate the hepatotoxicity of the coexistence of SBR-TMPs additives and antibiotics in zebrafish. Results indicated that low-order effects of antibiotics (e.g., enoxacin–lomefloxacin and ofloxacin–enoxacin–lomefloxacin) had relatively notable toxicity. The van der Waals interaction between additives and zebrafish cytochrome P450 enzymes primarily affected zebrafish hepatotoxicity. Zebrafish hepatotoxicity was also affected by the ability of SBR-TMPs to adsorb antibiotics, the relation between antibiotics, the affinity of antibiotics docking to zebrafish cytochrome P450 enzymes, electronegativity, atomic mass, and the hydrophobicity of the antibiotic molecules. This study aimed to eliminate the joint toxicity of TMPs and antibiotics and provide more environmentally friendly instructions for using different chemicals.

Characterisation of 3D-printable thermoplastics to be used as tissue-equivalent materials in photon and proton beam radiotherapy end-to-end quality assurance devices

Objective. To investigate the potential of 3D-printable thermoplastics as tissue-equivalent materials to be used in multimodal radiotherapy end-to-end quality assurance (QA) devices. Approach. Six thermoplastics were investigated: Polylactic Acid (PLA), Acrylonitrile Butadiene Styrene (ABS), Polyethylene Terephthalate Glycol (PETG), Polymethyl Methacrylate (PMMA), High Impact Polystyrene (HIPS) and StoneFil. Measurements of mass density ( ρ ), Relative Electron Density (RED), in a nominal 6 MV photon beam, and Relative Stopping Power (RSP), in a 210 MeV proton pencil-beam, were performed. Average Hounsfield Units (HU) were derived from CTs acquired with two independent scanners. The calibration curves of both scanners were used to predict average ρ, RED and RSP values and compared against the experimental data. Finally, measured data of ρ, RED and RSP was compared against theoretical values estimated for the thermoplastic materials and biological tissues. Main results. Overall, good ρ and RSP CT predictions were made; only PMMA and PETG showed differences >5%. The differences between experimental and CT predicted RED values were also <5% for PLA, ABS, PETG and PMMA; for HIPS and StoneFil higher differences were found (6.94% and 9.42/15.34%, respectively). Small HU variations were obtained in the CTs for all materials indicating good uniform density distribution in the samples production. ABS, PLA, PETG and PMMA showed potential equivalency for a variety of soft tissues (adipose tissue, skeletal muscle, brain and lung tissues, differences within 0.19%–8.35% for all properties). StoneFil was the closest substitute to bone, but differences were >10%. Theoretical calculations of all properties agreed with experimental values within 5% difference for most thermoplastics. Significance. Several 3D-printed thermoplastics were promising tissue-equivalent materials to be used in devices for end-to-end multimodal radiotherapy QA and may not require corrections in treatment planning systems’ dose calculations. Theoretical calculations showed promise in identifying thermoplastics matching target biological tissues before experiments are performed.

Experimental investigation and optimization for after-impact residual strength of a novel gradient corrugated structure

A novel structure based on a gradient corrugated architecture is introduced, and its after-impact residual strength is numerically and experimentally investigated. Low-velocity impact (LVI) and compression after impact (CAI) tests are conducted on designed specimens made of acrylonitrile butadiene styrene (ABS). The experiments reveal that the penetration depth increases linearly with increase in impact energy while the residual strength does not follow the same trend and its degradation rate is decreasing which implies that the structure tends to maintain its strength. A numerical model is developed to simulate the impact and after-impact response of structures with the error range of 2∼15 % for penetration depth values of LVI and less than 5 % error for the residual strength of CAI in comparison with experimental results. In order to maximize the after-impact tolerability, the structural architecture is optimized and realized that trapezoidal cells with decreasing gradient offer the highest specific strength. The sensitivity of the proposed structure to the impact location, with a higher average residual specific resistance, is lower than similar optimized configurations presented in literature.

Preparation of Poly(Styrene-co-Acrylonitrile)-Grafted Attapulgite via Simultaneous Reverse and Normal Initiation Atom Transfer Radical Polymerization (SR&NI ATRP) and Its Effect on Polycarbonate/Acrylonitrile-Butadiene-Styrene Terpolymer Ternary Composites

To further improve the comprehensive properties of polycarbonate/acrylonitrile–butadiene–styrene terpolymer blends (PC/ABS), in this work, styrene–acrylonitrile copolymer [P(St-co-An)] was grafted on the surface of attapulgite particles (ATP) by simultaneous reverse and normal initiation ATRP (SR&NI ATRP) to yield ATP@P(St-co-An) hybrid particles. Then a series of PC/ABS/ATP@P(St-co-An) composites were prepared via the melt blending method. The effects of ATP@P(St-co-An) content on the morphological, mechanical, thermal and rheological properties of the composites were investigated in detail. The core-shell ATP@P(St-co-An) hybrid particles with the polymer layer thickness of 20-40 nm were synthesized successfully according to the results of X-ray photoelectron spectrometer (XPS), Fourier transform infrared spectrometer (FTIR), gel permeation chromatography (GPC), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). The improvement in mechanical properties, reduced glass transition temperature (T g) difference between PC and ABS and micromorphology changes of the composites proved the compatibilization, strengthening, and toughening effect of the ATP@P(St-co-An). Compared with the PC/ABS blend, with strength and toughness of 50.8 MPa and 56.3 kJ/m2, when the ATP@P(St-co-An) content was 4 wt%, a reasonable balance (85.8 MPa and 86.2 kJ/m2) between strength and toughness was achieved with substantially enhanced thermal stability. Moreover, the composite showed more remarkable non-Newtonian behavior, and its processability was also improved. We believe this work provides an effective approach to optimize the compatibility and comprehensive properties of PC/ABS blends.

Design of Mold Flipper in an Effort to Improve The Efficiency of Mold Maintenance Process

Molding is a production process by forming raw materials using a rigid frame or model used in the manufacturing industry to mold materials called a mold. Injection molding is a technique in the manufacturing industry for molding thermoplastic materials. Thermoplasctic materials commonly molded with Injection Molding techniques are Polystyrene, Acrylonitrile Butadiene Styrene (ABS), PMMA (Polymethyl Methacrylatic) and others. The purpose of this research is to design and build a flipper molding tool for an easier and more efficient mold maintenance process. This research uses descriptive methods. Data is taken through direct observation and through reference books both from companies and websites and journals related to the report material. The data obtained was analyzed using descriptive analysis. it is found that the material used in the work is Carbon Steel (S45C). The process of making Flipper Clamps Mold has several stages, namely the Design Making Process, Material Selection Process, Cutting Process, Milling Process, Grinding Process, Drilling Process, Welding Process, and Assembly Process. With this Flipper Clamping tool, it is hoped that it can make it easier for operators to maintain and repair molds, because the previous mechanism requires two operators to flip molds that weigh more than 200 kg, now they only need to flip by turning the lever of this tool.

Characterization of the Alkali and Hydrolysis Resistance of Polymer-Impregnated, Alkali-Resistant Glass Filaments.

The aim of this series of tests was to characterize the alkali and water resistance of alkali-resistant (durability) glass filaments, which were optimized with two non-vulcanized formulations based on co-polymerizing styrene-butadiene rubbers (CemFil-SBR1 and CemFil-SBR2). Furthermore, it was assessed which of the two polymer-impregnated multifilament yarns is the better alternative for use in cementitious binders. For this purpose, the impregnated multifilament yarns were chemically conditioned for up to twelve months at temperatures of 23 and 50 °C in 2.5 percent sodium hydroxide solution and 2.5 percent potassium hydroxide solution as well as in 3 percent salt and distilled water. The samples were then subjected to material science tests. The liquid absorption capacities and the changes in the mass of the composite materials were determined at different times during conditioning. The load-bearing capacity of the samples was also tested using uniaxial fiber strand tensile tests. The durability of the polymer-impregnated multifilament yarns was described in detail in conjunction with scanning electron microscopy images and nominal cross-section determinations. The test liquids caused a reduction in strength during the storage period, which was accelerated by increased temperatures. The reduction in strength is mainly due to glass corrosion of the filaments. Glass corrosion is delayed due to the good impregnation quality, which fundamentally improves the durability of the yarns. The results of the durability tests show that the polymer-impregnated multifilament yarns CemFil-SBR2 are probably more suitable for use in cementitious binders, as they have better alkali and hydrolysis resistance.

The Effect of Acrylonitrile Butadiene Styrene (ABS) and Polypropylene (PP) Microplastics on Ulva lactuca L. and Ceramium diaphanum R. Algal Growth

The goal of this study was to determine the effects of acrylonitrile butadiene styrene and polypropylene microplastics as two typical classes for microplastic pollution on algal growth, lipids, carbohydrates, chlorophyll-a and total carotenoid content of Ulva lactuca L. and Ceramium diaphanum R. collected from the Gulf coast of Izmir province. The results demonstrate that ABS-MPs had no statistical effect (P&gt;0.05) on the various physiological parameters of U. lactuca macroalgae after 5 days of exposure, except for the total carbohydrate and lipid concentration. The chl-a value of C. diaphanum was considerably increased under the low concentration of ABS (25 mg L-1), increasing by 81.56% compared with the control while the amount of chl-a decreases (32.05%) in parallel with the increasing concentration of PP-MPs. Laboratory incubation experiments showed that MPs affect relative growth rate, pigments efficiency or carbohydrate content of C. diaphanum until reaching an extremely high concentration (100 mg L-1), indicating a high tolerance to MPs. The results showed that two macroalgae species, especially U. lactuca, were not highly affected at low MPs concentrations under laboratory conditions which were much higher than the levels of environmentally relevant concentrations.

DEVELOPMENT OF HYDROGENATED SBR-BASED VULCANIZATE WITH SUPERIOR TIRE TREAD PERFORMANCE

ABSTRACT Currently, the tire industry is exploring eco-friendly tires with improved rolling resistance, traction, abrasion resistance, and fatigue properties. The present study investigates the potentiality of the hydrogenated styrene butadiene rubber (HSBR), a special and modified grade of styrene butadiene rubber (SBR) as a tyre tread material. The rheological, mechanical, dynamic mechanical, abrasion resistance, fatigue resistance, aging resistance and ozone resistance properties of the developed HSBR-based composites were critically evaluated and compared with those of conventional rubbers such as natural rubber (NR), emulsion styrene butadiene rubber (ESBR) and solution styrene butadiene rubber (SSBR) based composites. Interestingly, the HSBR-based vulcanizates exhibited superior modulus, tensile strength, abrasion resistance, fatigue crack growth resistance, resistance to thermo-oxidative aging, and ozone resistance as compared to the conventional SBR–based vulcanizates. The modulus at 300% elongation of the HSBR-based vulcanizate was approximately 74% and 11% higher than that of the ESBR- and SSBR-based composites, respectively, whereas the improvements in tensile strength were approximately 88% and 64% and the improvements in abrasion resistance were approximately 250% and 200% than that of the ESBR and SSBR vulcanizates, respectively. The tensile strength and fatigue resistance characteristics of the HSBR vulcanizate were also nearly similar to those of the NR vulcanizate. The findings demonstrate that HSBR can be a potential tire tread material with robust physico-mechanical properties and durability.

Improving the energetic properties of 1,1-diamino-2,2-dinitroethene in PBX mixture

Abstract The new eyesight in the energetic materials focuses on reserving high efficiency together with optimization of safe handling. In this study, a novel nitramine, cis1,3,4,6-tetranitrooctahydroimidazo-[4,5-d]imidazole (BCHMX), is combined with 1,1diamino-2,2-dinitroethene (FOX7), and bound by a styrene-butadiene rubber fabricating an insensitive plastic bonded explosive (PBX) mixture. The obtained PBX was fully characterized in comparison with the familiar explosives; SEMTEX, EPX1 and other PBXs, filled by RDX (1,3,5trinitro-1,3,5-triazinane), HMX (1,3,5,7tetranitro-1,3,5,7-tetrazine). The related individual fillers were also included. Sensitivities to various stimuli and the velocities of detonation were measured for the composites in comparison with the selected explosives. EXPLO 05 has been applied to obtain the detonation properties of the tested explosives. Different relationships (comparing performance with sensitivities) are stated and discussed. The results showed that BC/FOX7 - SBR has very low sensitivity compared with the studied compositions while its performance has larger values.

Design and parametrization of TPMS lattice using computational and experimental approach

Triply periodic minimal surface (TPMS) based lattices are extensively explored as a scaffold design for bone regeneration. TPMS maintains zero mean curvature at each point and offers a large surface area comparable to a trabecular bone. The best four TPMS minimal surfaces (IWP. Neovius, primitive, and F-RD) were selected, designed, and fabricated using acrylonitrile butadiene styrene (ABS) resin through the stereolithography (SLA) technique. The results indicate that small changes in unit cell dimensions do not significantly alter the structure topology, which ensures stress distribution within the lattice remains relatively uniform across different unit cell sizes when the porosity level is constant. The optimal unit cell size (2 to 5 mm) and porosity (70 to 80%) significantly affect the compressive strength and surface area to volume (SA/V) ratio due to a unique arrangement of the internal architecture of each TPMS unit cell. The lattice structure (formed by stacking unit cell) of unit cell size 2.11 mm with 70% porosity exhibited a maximum compressive strength of 39.8 MPa in IWP, followed by Neovius, primitive, and F-RD-based lattice structures. Moreover, the lattice showed more stability under compression force, minimized stress concentration compared to a unit cell, and exhibited distinct deformation patterns at different strain levels during compression.