Butadiene Styrene Research Articles

Effects of Structurally Different Tertiary Amines on the Properties of Quaternized Anionic Exchange Membranes Potentially Applicable for Water Electrolysis.

In this work, two structurally different monoamines (trimethylamine [TMA] and N-methylpiperidine [N-MPip]) are used for the amination of a g-VBC-15 graft copolymer, obtained by the functionalization of a mechanically robust, commercially available styrene-butadiene block copolymer (SB) with vinylbenzyl chloride (VBC) via solution free-radical polymerization. Results demonstrate that g-VBC-15-based membranes quaternized with TMA have superior electrochemical performance than N-MPip counterparts; while, the mechanical properties are good and only slightly inferior to those of N-MPip. Therefore, TMA is the selected monoamine to be alternatively mixed with two polyamines (tetramethyl-1,3-propanediamine [TMPDA] and N,N,N',N'',N''-pentamethyldiethylenetriamine [PMDETA]) into different proportions, in order to modulate the average functionality of the amination mixture in terms of number of amine functional groups available for the quaternization reaction of the membranes. g-VBC-15-based membranes derived therefrom are extensively characterized to assess their thermal, mechanical, and ex situ electrochemical properties. Results indicate that membranes quaternized with a TMA/PMDETA mixture (90:10 in mole) display the highest conductivity among all the investigated membranes aminated with polyamine-based mixtures. Moreover, they have comparable mechanical and electrochemical properties to those quaternized with TMA, while exhibiting a reduced water uptake.

FTIR spectroscopy analysis assessment of reclaimed asphalt at asphalt mixing plants to optimize the recycling

Reclaimed asphalt pavements (RA) usually are fully recyclable in new asphalt mixtures. The properties of the individually aged and possibly modified bitumen in the RA will affect the mix design of the new asphalt mixture. Furthermore, the RA may contain hazardous PAH-contamination resulting from coal tar, which was applied in German road pavements up to the 1980′s. For identifying substances that impair or influence reusability of the RA the Fourier transform infrared spectroscopy (FTIR) method was modified. Within a total measuring time of approx. 20 min, the binder contained in a sample of granulated road construction material can be recovered by means of a rapid extraction and measured by FTIR-ATR. By evaluating the measured absorption spectra, samples which have to be considered as PAH-contaminated (with PAH contents ≥ 25 mg/kg) could be distinguished from non-contaminated reclaimed asphalt. Furthermore, the presence of styrene-butadiene-styrene (SBS) modification as well as viscosity-changing organic additives could be identified.

High flame retardant composite phase change materials with triphenyl phosphate for thermal safety system of power battery module

The thermal safety of battery pack has attracted much attention accompany with the growth in electric vehicles (EVs) in recent years. Although various battery thermal management systems (BTMS) are investigated by many research, the thermal runaway propagation (TRP) of battery packs under extremely abused conditions is just at the level of structural design and theoretical model. How to explore an innovative technology to improve the integrated thermal safety including the BTMS and TRP is still a great challenge. In this study, a multifunctional flame-retardant paraffin (PA)/styrene-butadiene-styrene (SBS)/expanded graphite (EG)/methylphenyl silicone resin (MPS)/triphenyl phosphate (TPP) composite phase change material (PSEMT) has successfully prepared. Besides, it has applied in 26650 ternary power battery modules. When the proportion of MPS and TPP is 1:2, the experimental results reveal that PSEMT possesses high thermal stability, and excellent flame-retardant properties owing to synergistic flame-retardant effect with phosphorus and silicon. Further, the cylindrical 26650 battery module with PSEMT exhibits optimum thermal management performance. Even at 2C discharge rate after ten cycles, the maximum operating temperature of battery module can still be maintained below 50 °C, and the maximum temperature difference is controlled within 4.6 °C. Additionally, it displays an excellent thermal runaway suppression through triggering by multiple heat sources. What's more, the battery with PSEMT can suppress the peak temperature and delay the occurrence time of thermal runaway. Therefore, it can be induced that the battery module with PSEMT can effectively avoid heat accumulation and significantly reduce its thermal safety risk. This study offers a new solution with promising prospects from the perspectives of energy storage and EVs, for balancing the temperature inconsistencies in batteries and suppressing thermal runaway in the battery packs.

Pyr-GC-Orbitrap-MS method for the target/untargeted analysis of microplastics in air

Pyrolysis-gas chromatography coupled to Orbitrap-mass spectrometry is a novel technique that allows the low level and precise determination of microplastics in environmental samples. In this paper, we develop and assess the target and untargeted performance of Pyr-GC-Orbitrap-MS. The method was optimized for 10 plastic polymers: polymethyl methacrylate, nylon-6,6, polypropylene, nitrile butadiene rubber, polyvinyl chloride, polyethylene terephthalate, acrylonitrile butadiene styrene, polyethylene, polycarbonate, and polystyrene. Standards were home-made using a diamond driller to attain mean sizes within the range of 45–382 µm. A step-by-step optimization of the analytical procedure was carried out. First, accurate mass measurement of each polymer at 60,000 resolution was studied to select the 3 most intense and selective quantification and confirmation ions. Second, internal standard quantification was optimized, and good linearity, repeatability, and reproducibility were obtained. Blank contribution and instrumental detection limit were evaluated for each polymer. Finally, the combined and expanded uncertainty of the Pyr-GC-Orbitrap-MS method was calculated to determine the sources of variation, considering that home-made standards were used. To evaluate method performance, targeted and non-targeted analysis of indoor air samples collected from gyms and department stores were carried out. The Pyr-GC-Orbitrap-MS methodology herein described can be applied for the quantitative assessment of MPs and other substances in different matrices.

A Study on the Properties of Composite Modified Mortar with Styrene-Butadiene Rubber Latex and Silica Fume.

To solve the problem of the poor abrasion resistance of concrete pavement surface mortar, this study substituted cement with equal amounts of styrene-butadiene rubber (SBR) latex and silica fume (SF) to investigate the effects of organic/inorganic material composite modification on the fluidity, drying shrinkage, mechanical properties, and abrasion resistance of cement mortar. Also in this study, the microstructure, product, and pore structure characteristics of the composite modified cement mortar were investigated using scanning electron microscope (SEM), X-Ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and the Brunauer-Emmett-Teller (BET) method. This research found that the sole substitution of SF negatively impacted the mortar's fluidity and drying shrinkage yet enhanced its mechanical strength and abrasion resistance; the incorporation of SBR latex improved fluidity, reduced shrinkage, and increased flexural strength but adversely affected the compressive strength of the mortar. Additionally, the enhancement of the mortar's abrasion resistance with SBR latex was significantly greater than that with SF. When SBR latex and SF were used together as substitutes, the latex struggled to offset the negative impact of SF on mortar fluidity but effectively reduced shrinkage; SF compensated for the detrimental effect of the latex on compressive strength. Moreover, the primary role in enhancing the mortar's abrasion resistance was played by the latex. Microscopic tests showed that SBR latex and SF could increase the content of calcium silicate hydrate (C-S-H) gel, inhibit the formation of ettringite (AFt) and reduce carbonation, refine the pore size of cement mortar, and effectively improve the microstructure of mortar.

Ultrafast universal fabrication of configurable porous silicone-based elastomers by Joule heating chemistry

Silicone-based elastomers (SEs) have been extensively applied in numerous cutting-edge areas, including flexible electronics, biomedicine, 5G smart devices, mechanics, optics, soft robotics, etc. However, traditional strategies for the synthesis of polymer elastomers, such as bulk polymerization, suspension polymerization, solution polymerization, and emulsion polymerization, are inevitably restricted by long-time usage, organic solvent additives, high energy consumption, and environmental pollution. Here, we propose a Joule heating chemistry method for ultrafast universal fabrication of SEs with configurable porous structures and tunable components (e.g., graphene, Ag, graphene oxide, TiO2, ZnO, Fe3O4, V2O5, MoS2, BN, g-C3N4, BaCO3, CuI, BaTiO3, polyvinylidene fluoride, cellulose, styrene-butadiene rubber, montmorillonite, and EuDySrAlSiOx) within seconds by only employing H2O as the solvent. The intrinsic dynamics of the in situ polymerization and porosity creation of these SEs have been widely investigated. Notably, a flexible capacitive sensor made from as-fabricated silicone-based elastomers exhibits a wide pressure range, fast responses, long-term durability, extreme operating temperatures, and outstanding applicability in various media, and a wireless human-machine interaction system used for rescue activities in extreme conditions is established, which paves the way for more polymer-based material synthesis and wider applications.

A machine learning approach to characterise fabrication porosity effects on the mechanical properties of additively manufactured thermoplastic composites

The investigation of the mechanical properties of additively manufactured (AM) composite has been the focus of several research over the past decades. However, testing constraints of time and cost have encouraged the exploration of more pragmatic methods such as machine learning (ML) for predicting these characteristics. This study builds on experimental investigations of the flexural, tensile, compressive, porosity, and hardness properties of 3D printed carbon fibre-reinforced polyamide (CF-PA) and carbon fibre-reinforced acrylonitrile butadiene styrene (CF-ABS) composites, proposing the application of ML for predicting these mechanical properties. A comprehensive comparative analysis of various machine learning approaches was executed, with a resultant accuracy ranging between 80 and 99%. The results unveiled the superior predictive performance of ensemble tree learners and the K-NN regressor algorithms when temperature and porosity are selected (based on correlation analysis) as predictors for material hardness and strength in tension, compression, and flexion. In particular, the model built on the extra-tree regressor algorithm demonstrated a remarkably robust fit, with R-squared evaluation scores of 0.9993 and 0.9996 for CF-PA and CF-ABS, respectively. This work develops a ML model that relates porosity to the other mechanical properties of AM composites and the prediction models’ exceptional accuracy, along with their precise alignment with experimental data, provide invaluable insights for the autonomous control and data-driven optimization of the structures.

Optimization of tribological characteristics in cryo-treated plastic/graphene oxide modified CFRP via ANN-based predictive modeling for aerospace applications

Carbon fiber reinforced polymers (CFRP) were modified with polycarbonate (PC)/acrylic butadiene styrene (ABS), and silanized graphene oxide deposited (using electrophoretic deposition) carbon fibers. Using Pin-on-Disc (POD) experiment, the wear rate (WR) and coefficient of friction (COF) of modified CFRP samples were determined for room-temperature (RT) and cryo-treated (CT) conditions. For RT samples, the largest reduction in COF compared to NEAT samples was for SGO samples by 25.6%, while the largest reduction in WR was for PC/ABS samples at 42.1%. But for CT samples, the maximum reduction in COF was 32.6% by SGO, and PC/ABS achieved the maximum reduction in WR by 41%. Also, Analysis of Variance (ANOVA) found “sample composition” to be the most critical component for volume loss mean, whereas Taguchi analysis refined the parameters and achieved the desired outcome. To predict wear behaviour, the Levenberg-Marquardt algorithm, artificial neural network, and linear regression were used. Based on mean squared error (MSE) loss, the Matlab-based Neural Network method performed best, with 0.35% MSE for RT samples and 0.88% for CT samples. This work helps to understand and enhance CFRP materials for wear-resistant applications using optimization techniques.

Study on the Compatibility of SBR and Asphalt Base Based on Molecular Simulation.

In the field of highway construction, the application of styrene-butadiene rubber (SBR)-modified asphalt has gained popularity across different levels of road surfaces. A crucial aspect in ensuring the efficacy of this modification lies in the compatibility between SBR and the matrix asphalt. To address this, the current study utilizes molecular dynamics simulation as a technique. By establishing a model for the SBR-modified asphalt mixture, the research quantifies the compatibility level between the SBR modifier and the asphalt. The aim is to uncover the underlying mechanisms of compatibility between the SBR modifier and the base asphalt, ultimately contributing to the improvement of the storage stability of SBR-modified asphalt, which holds significant importance. The investigation began with the creation of models for both the base asphalt and the SBR modifier. A model for the SBR-modified asphalt blending system was then formulated based on these initial models. After undergoing geometry optimization and annealing procedures, the model attained its lowest energy state, providing a reliable basis for examining the performance of SBR-modified asphalt. The study proceeded to calculate solubility parameters and interaction energies of the system to evaluate the compatibility between the SBR modifier and the base asphalt at various temperatures. The analysis of these parameters shed light on the compatibility mechanism between the two components. Notably, it was found that at a temperature of 160 ℃, the compatibility was significantly enhanced. The findings were further corroborated through scanning electron microscope and rheological tests. The outcomes of this research offer theoretical guidance for the application of SBR-modified asphalt.

Flexible phase change materials based on hexagonal boron nitride (hBN) surface modification and styrene-butadiene-styrene (SBS)/low-density polyethylene (LDPE) crosslinking for battery thermal management applications

In battery thermal management (BTM), flexible phase change materials (FPCMs) emerge as highly promising substances, owing to their simple installment and low contact thermal resistance. However, FPCMs based on high thermal conductivity fillers and polymers always suffer from the enduring challenges of poor high-temperature resistance and poor filler-matrix compatibility. To solve these problems, a novel strategy is reported in this work, wherein FPCMs with excellent filler-matrix compatibility and satisfactory high-temperature resistance are synthesized by two steps: functionalizing the hexagonal boron nitride (hBN) surface and inducing the inter crosslinking between Styrene-Butadiene-Styrene(SBS) and Low-density polyethylene(LDPE). Vinyltrimethoxysilane (VTMS) molecules were introduced on the surface of raw hBN by hydroxylation and silanization surface modification to improve the compatibility of hBN with the matrix. Concluding from the results, the addition of 6.7 wt% LDPE doubled the high-temperature resistance of FPCMs, enabling them to maintain their structural integrity even at 200 °C for 1 h. The prepared FPCMs also exhibited higher thermal conductivity (increased by 20.5 %), low leakage rate (<0.6 wt% after 70 heating–cooling cycles), high enthalpy (122 J g−1), and strong adhesion (>0.1 MPa), etc. In terms of BTM performance, the FPCMs-based passive cooling BTM presents remarkable temperature control capabilities (maximum temperature reduction by 16.3 ℃) and uniform temperature performance (maximum temperature difference < 2.5 ℃). Collectively, this work will provide a promising approach for the fabrication of high-performance FPCMs in BTM and other thermal management applications for electronic devices.

Investigation of NR, BR, and SBR composite material properties and internal mixer Wear under various lubricating oil media during mixing process

During the blending process, the choice of lubricant used in the internal mixer significantly affects the properties of composite materials. This study thoroughly investigates the mechanisms that enhance the mechanical properties and anti-wear characteristics of Natural Rubber/ Butadiene Rubber/Solution-Polymerized Styrene Butadiene Rubber composite materials by employing both commonly used lubricants and graphene-based lubricant mediums. The research offers data-driven insights to enhance material performance during internal mixer blending and protect the end-face metals. The incorporation of graphene as a lubricant additive results in its deposition on friction pair surfaces, forming a protective anti-wear layer that prevents direct contact between the friction pairs and effectively reduces wear.Throughout the blending process, the composite materials inevitably come into contact with the lubricant. This research reveals that the addition of lubricant improves the dispersion of SiO2 particles while reducing aggregate formation. Consequently, the SiO2 particles-TESPT-rubber crosslinking network becomes denser, significantly enhancing the performance of Natural Rubber/ Butadiene Rubber/Solution-Polymerized Styrene Butadiene Rubber composite materials. Specifically, when using commonly used lubricant mediums, the material's hardness, tensile strength, and tear strength increase by 0.88 %, 7.8 %, and 4.5 %, respectively. In contrast, under the graphene lubricant medium, these properties improve by 2.7 %, 16.8 %, and 24.9 %, respectively. Notably, Natural Rubber/ Butadiene Rubber/Solution-Polymerized Styrene Butadiene Rubber composite materials using the graphene lubricant medium experience substantial reductions in rolling resistance and improved anti-wet skid performance.When comparing Natural Rubber/ Butadiene Rubber/Solution-Polymerized Styrene Butadiene Rubber composite materials with and without lubricants, composites prepared with both commonly used lubricants and graphene lubricants show significant reductions in metal wear and changes in metal surface roughness. Metal wear decreases by 17.5 % and 28.7 %, respectively, while changes in metal surface roughness are reduced by 46.3 % and 68.7 %, respectively.

Fabrication of an Ultrastrong Formaldehyde-Free Wood Adhesive with an Organic-Inorganic Cross-Linking Network.

The wood industry faces challenges in producing eco-friendly, high-performance, and formaldehyde-free adhesives. In this study, carboxylated styrene-butadiene rubber (XSBR) was blended with polyamidoamine-epichlorohydrin (PAE) resin, and a controlled amount of CaCO3 powder was incorporated to create an adhesive with exceptional strength. The resulting three-layer plywood demonstrated remarkable dry and wet shear strengths of 3.09 and 2.36 MPa, respectively, and of 2.27 MPa after boiling water tests, comparable to that of phenolic resins. Additionally, the adhesive exhibited strong adhesion across various materials including glass, metal, etc. This exceptional performance was due to two primary factors: (1) the high-density chemical cross-linking reaction and the physical entanglement between XSBR and PAE; (2) the organic-inorganic hybrid involving metal ion complexation developed by CaCO3, which fostered molecular chain connections and enhanced the adhesive-material interface. These findings offer valuable references for further research in the field of wood adhesives.

Self-healing performance and rheological properties of styrene-butadiene-styrene block copolymer modified asphalt promoted by polyurea elastomers containing disulfide bonds

Self-healing asphalt is considered as one of the desirable methods to extend the service life of asphalt pavement. This research prepared a polyurea elastomer containing dynamic disulfide bonds (PUA)/styrene butadiene styrene block copolymer (SBS) composite modified asphalt. Moreover, a new asphalt self-healing performance evaluation method based on the damage process and results has been proposed. Subsequently, the self-healing ability of PUA, the distribution of modifier, the functional group and molecular weight of composite modified asphalt were characterized by fluorescence microscope, Fourier transform infrared spectroscopy (FTIR) and Gel permeation chromatography (GPC). The self-healing potential and limits of PUA/SBS composite modified asphalt was investigated through the proposed healing linear amplitude scanning (HLAS) test. Results show that the SBS content and fatigue load level are the main factors affecting the self-healing promotion effect of PUA. The critical point of healing fatigue strain (HFS) can indirectly characterize the threshold at which healing promoters exert their effects. Next, the addition of fillers will reduce the self-healing performance of PUA/SBS composite modified asphalt, but it still improves by at least 61.318% compared with SBS modified asphalt. Finally, the addition of self-healing elastomers (PUA) improves the permanent deformation resistance at high temperature and low-temperature crack resistance of SBS modified asphalt. The dynamic recombination of disulfide bonds can increase the fatigue cycle number of 4%SBS modified asphalt by 93.52% at a 5% load strain level.

Effect of pulverized coal/carbon black hybrid fillers on mechanical properties and thermal stability of styrene butadiene rubber composites

AbstractPulverized coal (coal) possesses a layered structure similar to graphite and is a potential reinforcing filler. In this paper, ball milling is used to reduce the particle diameter of coal. The coal is modified with KH‐560 to obtain K‐COAL and prepared K‐COAL/styrene‐butadiene rubber (SBR) composites. In addition, carbon black (CB) is modified to obtain CB‐Si69, K‐COAL and CB‐Si69 are added to SBR in different ratios to prepare COAL/CB/SBR composites. The results show that the addition of K‐COAL can improve the vulcanization performance, thermal stability, and mechanical properties of SBR composites, but the reinforcing effect is weak. In the COAL/CB/SBR composites, the vulcanization and mechanical properties of the composites gradually increase with the increase of CB, while those of the thermal stability decrease. The tensile strength of the 10 phr COAL/30 phr CB/SBR composite is 24.1 MPa, which is elevated by 1105% and 205% compared with the pure SBR and 40 phr K‐COAL/SBR composites, respectively. The composites maintain high elasticity while the tensile strengths are greatly improved, and the mechanical properties are significantly enhanced. In conclusion, this paper provides a reference for the clean utilization of coal and shows new possibilities for finding new fillers to replace CB.

Pengaruh Proses Annealing Terhadap Akurasi Dimensi Dan Kuat Tarik 3D Printing Menggunakan Filamen ST-PLA

3D printing is a tool used to make objects / test specimens in 3 dimensions, using the main material made from polymer. In 3D printers there are two types of filaments that are often used today, namely Polylactic acid or polylactide (PLA) material and Acrylonitrile butadiene styrene (ABS), the material used in this study is PLA material, this material was chosen because it has several advantages. Poly(lactic acid) (PLA) biodegradable thermoplastics have been used in various industrial fields including automotive, computer, food, and electrical equipment also used in medical devices, PLA is a biodegradable thermoplastic sourced from natural starches such as corn and sugarcane. Therefore, this study aims to find the highest tensile strength in PLA materials using several levels of testing, The highest tensile test result at one parameter level will be carried out by the annealing process to determine the effect of the annealing process on the tensile test specimen. The research method used in this study is the Taguchi method designed L9 with 3 factors and 3 levels, using the Analysis of Variance (ANOVA) analysis method. The test results showed that the highest tensile strength was located in study number 5, which was 44.866 Mpa, and the lowest average tensile test value was in study number 4, which was 40.033 Mpa.

Reducing the Environmental Impacts of Plastic Cosmetic Packaging: A Multi-Attribute Life Cycle Assessment

The global packaging industry has been growing significantly, resulting in an increase in waste and emissions. Social responsibilities, regulations and targets are shifting companies’ priorities to various sustainable practices. This study comprised a life cycle assessment (LCA) to quantify and compare key initiatives influencing the sustainability of plastic cosmetic packaging. The life cycle environmental effects of dematerialisation, recycled content, energy-saving initiatives and renewable energy powering the manufacturing processes, and the end-of-life (EoL) recycling rates of various scenarios, were evaluated. Moreover, a variety of fossil-based and bio-based polymers, such as acrylonitrile butadiene styrene (ABS), polypropylene (PP), polyethylene terephthalate (PET), wood–polymer composite (WPC) and polylactic acid (PLA), were considered. The study determined that dematerialisation and recycled content had the most beneficial impacts on packaging sustainability. When 100% recycled materials were used, an overall impact reduction of 42–60% was noted for all the materials considered. Using 100% renewable energy and applying measures to reduce the energy consumption in the manufacturing stage by 50% reduced the total impact by approximately 9–17% and 7–13%, respectively. Furthermore, it was concluded that PP had the lowest environmental impacts in the majority of the case scenarios considered, by an average of 46%.

Preparation of multifunctional chitosan derivative containing 10-undecenoyl and galloyl groups and its application in styrene-butadiene rubber/silica composites

The traditional small molecular rubber antioxidants have the shortcomings of single function, toxicity, and heavy dependence on non-renewable fossil resources, which limits their green, high-efficiency, and sustainable development in the rubber industry. To address this problem, in this work, we first developed a chitosan derivative containing 10-undecenoyl groups (COS-UC) and then combined it with the natural small molecular antioxidant gallic acid (GA) to prepare chitosan derivative containing 10-undecenoyl and galloyl groups (COS-UC-GA). The obtained COS-UC-GA was used as multifunctional modifier and applied in styrene-butadiene rubber (SBR)/silica composites. The effects of COS-UC-GA on the curing characteristics, crosslinking density, morphology, mechanical properties, and interfacial interaction of SBR/silica composites were explored in detail. The results indicated that the COS-UC-GA can effectively accelerate the vulcanization process of SBR/silica compounds, promote the uniform dispersion of silica, improve the mechanical properties of SBR/silica composites, and significantly enhance the interfacial interaction between the silica and rubber. This research provides a new perspective for developing green and eco-friendly multifunctional modifiers, which not only contributes to the comprehensive utilization of biomass resources, but also can promote the green development of the rubber industry.

Microscale mechanism and key factors of waterborne epoxy resin emulsified asphalt enhancing interlayer bonding performance and shear resistance of bridge deck pavement

In this research, samples of emulsified asphalt with varying concentrations of waterborne epoxy resin were prepared to augment the adhesion performance of emulsified asphalt in bonding layers. The bonding efficacy of waterborne epoxy resin emulsified asphalt (WEREA) was evaluated across different temperatures, application rates, and soaking durations. This evaluation simulated interlayer stress conditions using Binder Bond Strength (BBS) tests, 45° oblique shearing tests, and pull-out tests. To analyze the compositional evolution, polymer distribution, and microstructure of WEREA, a series of tests including Fourier Transform Infrared Spectroscopy, fluorescence microscopy, and Scanning Electron Microscopy were conducted. Findings suggest that WEREA significantly improves both bonding strength and shear strength of the bonding layer, exhibiting the least temperature sensitivity compared to unmodified and Styrene-Butadiene Rubber (SBR) modified emulsified asphalts. The optimal concentration of waterborne epoxy resin is identified as 20%, with an application rate of 0.9 kg/m². Upon curing, WEREA forms a cross-linked 'honeycomb' structure within the emulsified asphalt, facilitating the adsorption and anchoring of asphalt and leading to a transition from an asphalt continuous phase to an epoxy-asphalt biphasic structure. This study provides insights into the microscale mechanisms and critical factors underlying the enhanced interlayer bonding performance in bridge deck pavements offered by modified emulsified asphalt.

Types and concentrations of tire wear particles (TWPs) in road dust generated in slow lanes

Drivers commonly navigate their vehicles at moderate speeds in proximity to traffic lights. In this study, road dust samples were collected in the vicinity of traffic lights, as well as at a taxi stand (TS) situated between traffic lights, with considerations given to both forward direction (FD) and backward direction (BD). The characterization of tire wear particles (TWPs) in the road dust was meticulously conducted based on particle size. Notably, tire-road wear particles (TRWPs) were conspicuously absent in samples surpassing 500 μm. Furthermore, TRWPs comprised less than 1% of identified particles in the road dust samples of 212–500 μm, with their origin traceable to heavy vehicles rather than passenger cars. The abundance of TRWPs from heavy vehicles exhibited marked variations, with heightened prevalence in the TS and BD samples as opposed to the FD sample. For the samples smaller than 212 μm, the composition of natural rubber (NR) in TWPs demonstrated a diminishing trend with escalating particle size. Conversely, the composition of styrene-butadiene rubber (SBR) exhibited an upward trajectory independent of the sampling site. The NR composition ratio in TWPs followed the order: TS (17–55%) > FD (17–47%) > BD (13–36%), while the SBR composition ratio exhibited the sequence: BD (62–86%) > FD (48–79%) > TS (24–70%). The TWP concentrations in road dust obtained from the TS (0.35–0.82%) were discernibly lower than those in the FD (0.54–1.77%) and BD (0.61–1.29%) samples. Specifically, the average TWP concentrations in road dust samples, falling within the size range of 20–212 μm, were 0.45%, 1.06%, and 0.91% for the TS, FD, and BD samples, respectively. These concentrations were lower than the corresponding values observed in samples collected from a bus stop.

Evaluation method of modification effect of direct-to-plant SBS modifier on asphalt

To accurately evaluate the modification effect of direct-to-plant styrene–butadiene–styrene block copolymer (SBS) modifier on asphalt, a collection method for direct-to-plant SBS-modified asphalt was proposed in this paper, the qualitative and quantitative evaluation index system was established, and the feasibility of quantitative evaluation based on fluorescence microscopy images and visual inspection of the mixing effect was evaluated, the feasibility of quantitative evaluation indicators was also verified based on the asphalt indicators, rheological properties, and asphalt mixtures's pavement performances. The research results indicate that based on fluorescence microscopy images, by observing the distribution and swelling state of direct-to-plant SBS modifiers can qualitatively evaluate the modification effect of direct-to-plant SBS modifiers on asphalt. Based on the visual inspection of the mixing effect, observe the size and quantity of unmelted particles, determine the melting state of the direct-to-plant SBS modifier, and its modification effect on asphalt can be qualitatively evaluated. For the same direct-to-plant SBS-modified asphalt, the percentage of rotation viscosity between direct-to-plant SBS-modified asphalt and traditional SBS-modified asphalt at 135 ℃ (DAη(135℃)) and discrete coefficient of 135 ℃ rotational viscosity of direct-to-plant SBS-modified asphalt (CVη(135℃)) exhibit a linear relationship with direct-to-plant SBS-modified asphalt's penetration, softening point, and ductility, the smaller the CVη(135℃), the greater the DAη(135℃). The smaller the CVη(135℃) (the larger the DAη(135℃)), the larger the dynamic shear modulus (G*), the smaller the phase angle (δ), and the larger the rutting factor (G*/sinδ) at the same scanning temperature. The relationship between CVη(135℃) (DAη(135℃)) and direct-to-plant SBS modifier on the main technical indicators and rheological performance indicators of asphalt is relatively stable. There is a clear relationship between CVη(135℃) (DAη(135℃)) and the high-temperature stability, low-temperature crack resistance, and water stability of direct-to-plant SBS-modified asphalt mixture, all of which show that as CVη(135℃) decreases (DAη(135℃) increases), the pavement performances improve.