Butadiene Styrene Research Articles

Investigating the reinforcing effect of jute fiber in a PLA & PBAT biopolymer blend matrix for advanced engineering applications: Enhancing sustainability with bioresources

Renewable and biodegradable jute fiber (JF) is strategically incorporated as reinforcement in the poly (lactic acid) (PLA)/ poly (butylene adipate-co-terephthalate) (PBAT) matrix through melt blending. The resulting composites are comprehensively characterized to assess their mechanical properties, thermal stability, and morphological features. Scanning electron microscopy (SEM) is employed to scrutinize the interfacial bonding between the jute fibers and the biopolymer blend matrix. "The impact properties of the PLA/PBAT/JF 15 % composite (PLA/PBAT reinforced with 15 % jute fiber) are compared with a commercially available car dash box. Additionally, a composite fabricated from the recycled car dash box reinforced with 15 % jute fiber is evaluated. The results indicate that the developed composite demonstrates compatibility comparable to Acrylonitrile Butadiene Styrene (ABS) based engineering plastics." This investigation offers insights into the potential of bio-inspired jute fiber reinforcement to enhance the properties of the PLA/PBAT biopolymer blend matrix, thereby increases the scope in engineering applications other than single use application.

Quantifying microplastics in sediments of Jinzhou Bay, China: Characterization and ecological risk with a focus on small sizes

Small-sized microplastics (MPs) pose greater ecological toxicity due to their larger surface area, which makes them more likely to act as carriers for other pollutants and to be ingested by aquatic organisms. However, traditional visual analysis often neglects small-sized MPs and their associated ecological risk. This study utilized Laser Direct Infrared (LDIR) spectroscopy and traditional visual analysis to examine MPs in 31 sediment samples from Jinzhou Bay, a typical semi-enclosed bay located at the economic center of Dalian, China. The results showed significant heterogeneity in MP distribution, with averages of 1192 and 2361 items/kg dry weight reported by visual analysis and LDIR spectroscopy, respectively. LDIR spectroscopy identified MPs as small as 10 μm, with the majority of MPs (89.21 %) within the 10–250 μm range, and a significant proportion (46.45 %) between 10 and 50 μm among them. However, visual analysis was limited to detecting MPs >50 μm, and significant portions were identified between 50 and 100 μm (49.36 %) and 100–250 μm (31.01 %), missing a substantial fraction of smaller MPs. The predominant polymers identified were polyamide (PA), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and acrylonitrile butadiene styrene (ABS). LDIR spectroscopy demonstrated a strong positive correlation between MP abundance and clay content, a relationship not observed with traditional visual analysis. The Potential Ecological Risk Index (PERI) indicated that over 87 % of sites posed an extremely high risk according to LDIR spectroscopy, compared to 51 % by traditional visual analysis. These discrepancy underscores the underestimation of ecological risks by traditional methods, particularly for small-sized MPs. High-risk polymers such as polyvinyl chloride (PVC), ABS, and polyurethane (PUR) significantly influenced PERI values. These findings highlight the critical need for precise identification and thorough risk assessment of small-sized MPs in environmental studies and offer insights for understanding of MP vertical migration in aquatic environments, particularly in the context of co-settlement with sediments.

Improved wet skid resistance of NR/SBR composites induced by irradiation vulcanised styrene-butadiene rubber particles

Improving the wet skid resistance of tire tread is very important for the safety of vehicle driving. Using a novel ultrafine full-vulcanised powdered styrene-butadiene rubber (UFPSBR), this work prepared an advanced UFPSBR/nature rubber (NR)/styrene-butadiene rubber (SBR) composites used for the tire tread. On one hand, the UFPSBR improves the loss factor (tanδ) values of the UFPSBR/NR/SBR composites in temperature range from 0 °C to 10 °C, indicating that the UFPSBR modified tire tread has better wet skid resistance. On the other hand, the UFPSBR increases the surface roughness and complex modulus of the UFPSBR/NR/SBR composites while decreasing the water contact angle of the UFPSBR/NR/SBR composites, which is conducive to increasing the wet skid resistance of tire tread by puncturing the water film or leading a thinner water film between tire tread surface and road surface. Above researches are more comprehensive and benefit for studying the advanced green tire with high wet skid resistance.

Revealing the Impact of Viscoelastic Characteristics on Performance Parameters of UV-Crosslinked Hotmelt Pressure-Sensitive Adhesives: Insights from Time-Temperature Superposition Analysis.

This study emphasizes the influential role of rheology in decoding the viscoelastic properties of pressure-sensitive adhesives (PSAs) vital to predicting key application features such as shear, tack, and peel, depending on the flow characteristics of PSAs during bonding and debonding processes. By applying the principle of time-temperature superposition (TTS), we extend the scope of our frequency analysis, surpassing the technical constraints of the available apparatus. Our exploration aims to uncover the general correlations between PSAs' viscoelastic properties and their performance in end-use applications. Initially, the adhesive performance and viscoelastic properties of a UV-crosslinkable styrene-butadiene-styrene (SBS) model adhesive prior and subsequent to UV irradiation were examined. The subsequent crosslinking reaction increased cohesive strength and heat resistance, although tack and peel strength observed a substantial decline. We successfully demonstrated these effects by logging the viscoelastic properties, specifically the storage modulus G' at lower frequencies, which mirrors the shear strength at higher temperatures and the shift in the tan δ peak to represent each PSA's tack. These correlations were partially reflected in three commercial UV crosslinkable acrylic PSA products, although the effect of UV irradiation was less distinctive. This study also revealed the challenges in predicting tack and peel strength, which result from a complex interplay of bonding and debonding processes. Our findings reinforce the necessity for more sophisticated analysis techniques and models that can accurately predict the end-use performance of PSAs across different physical structures and chemical compositions. Further research is needed to develop these predictive models, which may reduce the need for labor-intensive testing under real-life conditions.

Evaluating exposure-response relationship in 1,3-butadiene and leukemia studies.

1,3-Butadiene (BD) exposure's link to leukemia is under regulatory scrutiny. The assessment methods for BD exposure risks have evolved from early animal and limited human studies to advanced exposure-response modelling with comprehensive quantitative data. The objec- tive of this study is to explore the nuances of exposure-response modelling, investigating how various statistical methods have influenced the quan- tification of exposure-response relationships. Although this study was not conducted as a formal systematic review, a search was performed in Medline/Pubmed to identify all human studies on leukemia risk assessment for BD exposure. This search included articles written in English. The electronic search spanned from inception of records until July 23, 2023, using the search term: "butadiene AND (leukaemia OR leukemia OR myeloid OR lymphoid)" and was restricted to human species. Focusing on the synthetic styrene-butadiene rubber (SBR) industry cohort study conducted by the University of Alabama at Birmingham, USA, this review evaluates various statistical models and factors influenc- ing exposure-response modelling. Peak exposures to BD may be more influential in the dose-response relationship than cumulative or long-term exposure. The authors recommend utilizing β-coefficients derived from the latest SBR study update, employing Cox proportional hazard modelling, non-lagged and non-transformed cumulative BD exposure, and adjusting for age and peak BD exposure. The study reveals that statistical model selection has a limited impact on the calculated dose-response effects. The significant variation in estimated cancer mortality values arises from additional assumptions needed for metrics like the excess leukemia risk or the occupational BD effective concentration. In con- clusion, this study provides insights into exposure-response modelling for BD exposure and leukemia mortality, highlighting the importance of peak exposures. The recommended statistical approach offers a reliable basis for regulatory risk assessment and public health population metrics. Int J Occup Med Environ Health. 2024;37(3):300-10.

Mechanically sustainable and primary recycled thermo-responsive ABS–PLA polymer composites for 4D printing applications: Fabrication and studies

Abstract 3D printing is one of the plastic recycling processes that deliver a mechanically sustainable product and may be used for 4D printing applications, such as self-assembly, sensors, actuators, and other engineering applications. The success and implementation of 4D printing are dependent on the tendency of the shape memory with the action of external stimuli, such as heat, force, fields, light, and pH. Acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) are the most common materials for fused filament fabrication-based 3D printing processes. However, the low-shaped memory tendency on heating and weaker and less rigidity of ABS limit the application domains. PLA is an excellent responsive behavior when the action of heat has high stiffness. The incorporation of PLA into ABS is one of the solutions to tune the shape memory effect for better applicability in the 4D printing domain. In this study, the primary recycled PLA was incorporated into the primary recycled ABS matrix from 5 to 40% (weight%), and composites were made by extrusion in the form of cylindrical filaments for 4D printing. The tensile and shape memory properties of the recycled ABS–PLA composites were investigated to select the best combination. The results of the study were supported by fracture analysis by shape memory analysis, scanning electron microscopy, and optical microscopy. This study revealed that the prepared ABS–PLA-based composites have the potential to be applied in self-assembly applications.

Assessment of microplastic pollution and polymer risk in the sediment compartment of the Limfjord, Denmark

Estuarine sediments intercept and temporarily retain microplastics before they reach the marine seafloor, impacting various organisms, including key commercial species. This highlights the critical need for research on microplastic exposure in these transitional environments. This study provides a detailed assessment of microplastic pollution in the sediment compartment of the Limfjord, a 1500 km2 large Danish fjord, and introduces the Polymer Hazard Index (PHI) as a tool for evaluating polymer-specific risks. Thirteen sediment samples were collected, covering an anthropogenic gradient along the fjord. State-of-the-art methods were applied for extracting and identifying (FPA-μFT-IR imaging) microplastics (10–5000 μm). Our results indicate that microplastic contamination is pervasive across all sampled locations with concentrations ranging from 273 to 4288 particles kg−1, with a predominance of small microplastics (<100 μm). The estimated mass-based concentrations ranged between 2.60 × 104–1.11 × 106 ng kg−1. Overall, we estimated a microplastic stock of 3.8 × 103–1.65 × 105 kg in the surface sediments of the Limfjord, i.e., some 2.5–110 kg km−2. The application of the PHI revealed significant risks associated with specific polymers, such as polyacrylonitrile (PAN) and acrylonitrile butadiene styrene (ABS), underscoring the importance of considering polymer-specific hazards in environmental assessments.

Enhancing asphalt-based waterproof materials for building cement substrates: Modifications, construction, and weathering resistance

Three distinct systems of asphalt-based waterproof material structures were designed for building cement substrates. These asphalt-based waterproof materials were modified using either Styrene Butadiene Rubber (SBR) or Ethylene Acrylic Acid Copolymer (EAA) along with various inorganic fillers. To enhance the adhesion between the waterproof materials and the cement substrate, the surface of the cement substrate was chemically treated with either γ-methacryloyloxypropyltrimethoxy silane (KH-570) or vinyltrimethoxy silane (SG-Si 171) through atomization spraying and infrared irradiation. The adhesion properties and debonding failure modes of waterproof materials for cement substrates were analyzed, and six groups of samples with relatively good adhesion properties were screened for further environmental aging tests. The samples were subjected to temperature fluctuations, water immersion, freeze-thaw cycles, thermal aging, acid, alkali, and salt, to identify favorable asphalt-based waterproof structure systems for five climate zones, acid rain-affected regions, and saline-alkali-affected regions in China. These results provide valuable insights for designing effective waterproof materials for different environments.

Improving the crashworthiness of bi-tubular architectures with ABS cores under axial loading: Experimental and numerical investigation

In this study, quasi-static axial compression tests were conducted on mild steel bi-tubular architectures with rectangular nested tube (RNT) and square nested tube (SNT) geometries to evaluate their crushing and crashworthiness performance. A multi-criteria decision-making approach was employed to identify the optimal energy-absorbing architecture. The SNT structure, with the smallest gap size between the inner and outer tubes, exhibited the most desirable energy absorption characteristics among the considered cases. Acrylonitrile butadiene styrene (ABS) cores, with either rhombic or square cell configurations, were used to enhance the energy absorption performance of the SNT structure. A finite element model was created to evaluate the responses of the SNT structure filled with ABS cores. The validity of finite element simulations of the ABS cores and optimal architecture under axial compression were confirmed by comparing them with experimental results. The integration of the cores into the nested architecture enhanced crashworthiness performance and contributed to the control of the structure deformation. The SNT structure filled with rhombic ABS core exhibited superior crashworthiness performance compared to the counterpart filled with square core. The energy absorption of nested SNT structures filled with rhombic ABS core can be 116.93% greater than the corresponding non-filled structure. The crashworthiness indices of ABS-filled structures were highly sensitive to the number of cells and wall thickness of the core. A nested architecture with an ABS core could serve as a novel architecture for energy-absorbing devices.

Laboratory Evaluation of Wear Particle Emissions and Suspended Dust in Tire–Asphalt Concrete Pavement Friction

This study aims to evaluate the tire–road-wear particles (TRWPs) and suspended dust generated based on the nominal maximum aggregate size (NMAS) of the polymer-modified stone mastic asphalt (SMA) mixtures indoors. The SMA mixtures containing styrene butadiene styrene (SBS) polymer and the NMASs of 19, 13, 10, 8, and 6 mm were used. Dust was generated from the wear of the tires and the pavement inside the indoor chamber by using the laboratory tire–road-wear particle generation and evaluation tester (LTRWP tester) developed by Korea Expressway Corporation (KEC). In this method, a cylindrical asphalt-mixture specimen rotates in the center, and a load is applied using three tires on the sides of the test specimen. During the test, a digital sensor was used to measure the concentration for each particle size. After the test was completed, the dust was collected and weighed. According to the test results, the generated TRWP emissions were reduced by approximately 0.15 g as the NMAS of the SMA mixture decreased by 1 mm. TRWP emissions decreased by 20% when using the 6 mm SMA mixture compared to the 13 mm SMA mixture. For practical application, a predicted equation of TRWP emissions estimation was developed by using the concentration of suspended dust measured by the digital sensor in the LTRWP tester. LTRWP can be used as an indoor test method to evaluate pavement and tire materials to reduce the amount of dust generated from tire and pavement wear.

Rheo-Optical Near-Infrared (NIR) Characterization of Styrene-Butadiene Rubber (SBR) Using Two-Trace Two-Dimensional (2T2D) Correlation Analysis.

A rheo-optical characterization technique based on the combination of near-infrared (NIR) spectroscopy and tensile testing was applied for the first time to an actual rubber sample based on styrene-butadiene rubber (SBR) including silica filler. When SBR samples were subjected to mechanical deformation, changes in the NIR spectral features were readily captured. Two-trace two-dimensional (2T2D) correlation analysis was then applied to the sets of NIR spectra to clearly reveal the subtle but pertinent difference between the NIR spectral features of the initial and deformed SBR. The initial deformation of the sample induces greater deformation of the soft butadiene groups than of the hard styrene groups. The inclusion of the silica filler and a coupling agent (CA) essentially develops firm links between the silica and butadiene via the CA to restrict the displacement of the butadiene during the tensile deformation of the system. The development of such linkage requires even more mechanical force to deform the SBR, which, in turn, improves Young's modulus of the rubber system. Asynchronous correlation spectra of SBR with no silica filler revealed that, during the deformation of the SBR, the butadiene groups were initially deformed, and this feature was then replaced by the predominant deformation of the hard styrene groups. On the other hand, this correlation feature became somewhat unclear when a similar analysis was applied to the SBR sample with silica filler, revealing subtle differences in interaction between individual comonomer functional groups distributed randomly along the copolymer chain and CA.

Development of a Zr-Based Metal-Organic Framework (UiO-66) for a Cooperative Flame Retardant in the PC/ABS.

Polycarbonate/acrylonitrile butadiene styrene (PC/ABS) blends are widely used as engineering plastic alloys; however, they have a low fire safety level. To improve the flame-retardant property of PC/ABS, a zirconium-based metal-organic framework material (UiO-66) was synthesized with zirconium chloride and terephthalic acid and used as a flame-retardant cooperative agent. Its flame-retardant performance and mode of action in the PC/ABS blends were carefully investigated. The results showed that UiO-66 had good thermal stability and delayed the pyrolysis of the materials, thus significantly enhancing the efficiency of intumescent flame retardants. By compounding 7.0 wt% hexaphenyloxy-cyclotri-phosphazene (HPCTP) with 3.0 wt% UiO-66, the PC/ABS blends reached a limiting oxygen index value of 27.0% and V0 rating in the UL-94 test, showing significantly improved resistance to combustion dripping. In addition, UiO-66 enhanced the smoke and heat suppression characteristics of the intumescent flame-retardant materials. Finally, the flame-retardant mode of action in the blends was indicative of UiO-66 having a cooperative effect on the flame-retardant performance of PC/ABS/HPCTP materials. This work provides good ideas for further development of the flame-retardant ABS/PC.

Efficient adsorption of waste carbon nanotube by polyacrylamide gel to form wrinkled core-shell particles towards multifunctional composites for EMI shielding and sensing

Waste carbon nanotubes (CNTs) have always been a potential threat to the environment and biological health. However, the efficient recycling and utilization of CNTs has received little attention. Here, we used chemically cross-linked polyacrylamide (PAM) particles to adsorb waste CNTs in water to prepare PAM@CNT core-shell particles, which were blended with thermoplastic styrene-butadiene rubber (SBS) to prepare flexible composites. The concentration of residual CNTs in the supernatant was less than 3.5 μg mL−1, which meets the safety standards for discharge. The unique core-shell structure enables the composites with a thickness of 1 mm to exhibit high electromagnetic interference shielding effectiveness (53.3 dB) and low reflectivity (1.4 dB) at 30 wt% CNT content. In addition, at a CNT content of 10 wt%, the composites exhibit superior sensing properties concerning strain and solvents. Moreover, the composites prepared from different sources of waste CNTs have the same sensing properties. This work provides an effective strategy for the highly efficient recycling of waste CNTs for the preparation of green, high-performance multifunctional polymer composites for EMI shielding, human motion and solvent leakage monitoring, and solvent category differentiation.

Autohesion Mechanisms at Interfaces Between Random Copolymer Melts: Mesoscopic Simulations with Realistic Coarse-Grained Models.

The increase in welding time during the interdiffusion of a pair of non reacting random copolymer melts favors the strength rate of healing at the interface. Furthermore, the diffusion kinetic during the interpenetration of copolymer chains across the interface is strongly dependent on molecular weight. In this paper we perform mesoscopic simulations with realistic coarse grain models to study the autohesion mechanism across the interface between slightly entangled styrene-butadiene random copolymer melts.

High Young's Modulus Li6.4La3Zr1.4Ta0.6O12-Based Solid Electrolyte Interphase Regulating Lithium Deposition for Dendrite-Free Lithium Metal Anode.

Artificial solid electrolyte interphase (SEI) layers have been widely regarded as an effective protection for lithium (Li) metal anodes. In this work, an artificial SEI film consisting of dense Li6.4La3Zr1.4Ta0.6O12 (LLZTO) nanoparticles and polymerized styrene butadiene rubber is designed, which has good mechanical and chemical stability to effectively prevent Li anode corrosion by the electrolyte. The LLZTO-based SEI film can not only guide Li to uniformly deposit at the interface but also accelerate the electrochemical reaction kinetics due to its high Li+ conductivity. In particular, the high Young's modulus of the LLZTO-based SEI will regulate e- distribution in the continuous Li plating/stripping process and achieve uniform deposition of Li. As a consequence, the Li anode with LLZTO-based SEI (Li@LLZTO) enables symmetric cells to demonstrate a stable overpotential of 25 mV for 600 h at a current density of 1 mA cm-2 for 1 mA h cm-2. The Li@LLZTO||LFP (LiFePO4) full cell exhibits a capacity of 106 mA h g-1 after 800 cycles at 5 C with retention as high as 90%. Our strategy here suggests that the artificial SEI with high Young's modulus effectively inhibits the formation of Li dendrites and provides some guidance for the design of higher performance Li metal batteries.

3D printing of continuous metal fiber-reinforced recycled ABS with varying fiber loading

PurposeThe current study aims to develop a 3D-printed continuous metal fiber-reinforced recycled thermoplastic composite using an in-nozzle impregnation technique.Design/methodology/approachRecycled acrylonitrile butadiene styrene (RABS) plastic was blended with virgin ABS (VABS) plastic in a ratio of 60:40 weight proportion to develop a 3D printing filament that was used as a matrix material, while post-used continuous brass wire (CBW) was used as a reinforcement. 3D printing was done by using a self-customized print head to fabricate the flexural, compression and interlaminar shear stress (ILSS) test samples to evaluate the bending, compressive and ILSS properties of the build samples and compared with VABS and RABS-B samples. Moreover, the physical properties of the samples were also analyzed.FindingsUpon three-point bend, compression and ILSS testing, it was found that RABS-B/CBW composite 3D printed with 0.7 mm layer width exhibited a notable improvement in maximum flexural load (Lmax), flexural stress at maximum load (sfmax), flex modulus (Ef) and work of fracture (WOF), compression modulus (Ec) and ILSS properties by 30.5%, 49.6%, 88.4% 13.8, 21.6% and 30.3% respectively.Originality/valueLimited research has been conducted on the in-nozzle impregnation technique for 3D printing metal fiber-reinforced recycled thermoplastic composites. Adopting this method holds the potential to create durable and high-strength sustainable composites suitable for engineering applications, thereby diminishing dependence on virgin materials.

Insights into the photoreactivity mechanisms of micro-sized rubber particles with different structure: The crucial role of reactive oxygen species and released dissolved organic matter

Micro-sized rubber particles (MRPs), as a significant component of tire wear particles (TWPs), increasingly garnered attention due to the potential ecological risks. However, the impact of photoaging of MRPs and the characteristics of the dissolved organic matter (DOM) derived from MRPs on the photoreactivity of co-existing pollutants is remain unclear. To bridge this knowledge gap, this study selected MRPs with different structure including butadiene rubber (BR), styrene butadiene rubber (SBR) and nitrile butadiene rubber (NBR) and took tetracycline (TC) as the target pollutant to firstly study potential effects of structural characteristics and active components of MRPs on TC photodegradation process under simulated sunlight irradiation. The results indicated that BR, NBR and SBR enhanced TC photodegradation to varying extents, with SBR having the most pronounced effect. This effect was attributed mainly to the high electron transport capacity and the generation of more triple excited DOM (3DOM*) of SBR, thereby producing more active species (•OH and 1O2) and significantly promoting TC photodegradation. Additionally, the unsaturated bonds and aromatic groups in MRPs-DOM was identified as another crucial factor influencing their photoreactivity. This study will provide a new perspective for understanding the potential ecological effects between MRPs and co-existing pollutants in the natural environment.

Enhanced carbon-based back contact electrodes for perovskite solar cells: Effect of carbon paste composition on performance and stability

To address the issue of cost and instability in perovskite solar cells (PSCs), it is promising to substitute the regular hole collecting electrode i.e., spiro-OMeTAD/Au with inorganic hole transport layer (HTL)/carbon electrode. In this study, three carbon pastes were investigated with different binders: polymethyl methacrylate (PMMA), styrene-butadiene-styrene (SBS) and ethyl cellulose (EC). Carbon layers were compared in terms of mechanical stability, conductivity and performance as back contact electrodes in PSCs with an inorganic HTM composed of CuInS2 nanoparticles. To assess mechanical properties of the carbon pastes, adhesion tests by using tape, ultrasonication in the media of deionized water and acidic deionized water, and also flexibility test were performed. The carbon layer based on SBS carbon paste (SBS-CP) was intact after adhesion tests and over 1017 cycles of flexibility test. The one based on PMMA carbon paste (PMMA-CP) didn't tolerate all mechanical tests and disintegrated. The carbon layer based on EC carbon paste (EC-CP) partly damaged after adhesion tests and didn't pass the flexibility test. The best efficiency of 18.6 % was obtained for a device based on SBS-CP and significant shelf-life stability over 172 days stored in relative humidity of 40 % and dark.

Abrasion Behaviors of Silica-Reinforced Solution Styrene-Butadiene Rubber Compounds Using Different Abrasion Testers.

Solution styrene-butadiene rubber (SSBR) is widely used to improve the properties of tire tread compounds. Tire wear particles (TWPs), which are generated on real roads as vehicles traverse, represent one of significant sources of microplastics. In this study, four SSBR compounds were prepared using two SSBRs with high styrene (STY samples) and 1,2-unit (VIN samples) contents, along with dicyclopentadiene resin. The abrasion behaviors were investigated using four different abrasion testers: cut and chip (CC), Lambourn, DIN, and laboratory abrasion tester (LAT100). The abrasion rates observed in the Lambourn and LAT100 abrasion tests were consistent with each other, but the results of CC and DIN abrasion tests differed from them. The addition of the resin improved the abrasion rate and resulted in the generation of large wear particles. The abrasion rates of STY samples in the Lambourn and LAT100 abrasion tests were lower than those of VIN samples, whereas the values in the CC and DIN abrasion tests were higher than those of VIN samples. The wear particles were predominantly larger than 1000 μm, except for the VIN sample in the DIN abrasion test. However, TWPs > 1000 μm are rarely produced on real roads. The size distributions of wear particles > 1000 μm were 74.0-99.5%, 65.9-93.4%, 7.2-95.1%, and 37.5-83.0% in the CC, Lambourn, DIN, and LAT100 abrasion tests, respectively. The size distributions of wear particles in the Lambourn and LAT100 abrasion tests were broader than those in the other tests, whereas the distributions in the CC abrasion test were narrower. The abrasion patterns and the morphologies and size distributions of wear particles generated by the four abrasion tests varied significantly, attributable to differences in the bound rubber contents, crosslink densities, and tensile properties.

Effect of additively manufactured polymeric inserts on impact response of construction safety helmets

Purpose Struck-by accidents (i.e. being hit by a falling object) are a leading cause of traumatic brain injuries in the construction industry. Despite the critical role of hard hats in minimizing such injuries, their overall design has not appreciably changed in decades. Therefore, this study aims to explore the potential benefits of modifying commercially available hard hat designs by incorporating a compliant cantilever and a sacrificial, energy-absorbing structure to enhance their protective capabilities against impacts. Design/methodology/approach This study involved conducting experimental impact tests to obtain the head acceleration attenuation using hard hats with a variety of compliant cantilever lattice insert designs. These lattice inserts were additively manufactured using three polymeric materials, including polylactide (PLA), acrylonitrile butadiene styrene, high-impact polystyrene and three porosity levels. A Hybrid III head/neck assembly was fitted with each hard hat design, and experimental drop tests were conducted using a 1.8-kg steel impactor dropped from 1.83 m. The maximum acceleration and head injury criterion (HIC) values were obtained for each test. Findings Analysis of variance revealed that HIC was significantly reduced for all lattices with 56% porosity (p &lt; 0.023) compared to the control (unmodified) hard hat. The most effective insert was found to be a PLA insert with 56% porosity, which reduced the HIC value by 38% compared to the control (unmodified) hard hat, with a statistically significant p-value of 0.018. Originality/value The data present in this study reveals that simple and inexpensive modifications can be made to existing hard hat designs to reduce injury risk from overhead impacts.