Butadiene Styrene Polymer Research Articles

Evaluation of asphalt anti-cracking performance of SBS polymer with SCB method and deep learning

In recent years, there have been unprecedented developments in artificial intelligence. Object detection, voice recognition, face recognition etc. are some of the artificial intelligence applications. In this study, an auxiliary method for the automatic detection of cracks, one of the main deterioration problems on highways, is proposed. The crack formation of hot mix asphalts is investigated with an image processing method modeled with Attention SegNet architecture. Styrene-butadiene-styrene (SBS), the most widely used additive in bitumen modification, was used at 2 %, 3 %, and 4 % ratios to modify 50/70 bitumen. Semi-circular asphalt specimens obtained with SBS modified bitumen were subjected to a semicircular bending (SCB) test and fracture performance was investigated. The effects of different temperature, notch size and additive on crack detection performance are evaluated. In the experimental study, maximum load, fracture energy, fracture toughness (KIC) values were obtained at low temperature, and resistance values against crack propagation were obtained by applying the J-integral method at intermediate temperature. The results demonstrated that with the addition of SBS, the fracture strength and maximum load values increased at each temperature value, with the 4 % SBS mixture offering the highest performance. Moreover, the image segmentation performed with SegNet provided high accuracy and precision values for cracks. It was observed that the accuracy values of the image processing methods decreased at low temperature, while at high temperature, higher accuracy values were obtained as the cracking rate.

Upcycling of waste acrylonitrile butadiene styrene as N-doped carbocatalyst for peroxymonosulfate-induced degradation by solvothermal process

Advanced upcycling of post-consumer waste plastics into functional carbocatalyst has emerged rapidly as a strategy for simultaneously achieving waste plastics disposal and alternative catalysts fabrication. In this study, this type of magnetic N-doped carbocatalyst hybrid was fabricated by a facile solvothermal impregnation of metallic nitrates into waste acrylonitrile butadiene styrene polymer. The key point of the process was that solvothermal impregnation remarkably enhanced a homogeneous metal dispersion and graphitic N structure was stably introduced into carbocatalyst due to N heteroatoms in inherent structure of waste plastics. It was found that carbocatalyst with predominant encapsulation of magnetic CoFe2O4, Fe0.64Ni0.36 and CoFe possessed excellent catalytic performance to activate peroxymonosulfate with substantial degradation of 98.3% synthetic azo contaminant. Mechanism study indicated that graphitic N and metal species exhibited strong synergistic effects for peroxymonosulfate activation to generate SO4·−, ·OH and 1O2. This system achieves a dual-pathway degradation and electron transfer from azo contaminant to peroxymonosulfate to dominate degradation of azo contaminant, providing a new insight into magnetic carbocatalyst confinement from plastic scrap for peroxymonosulfate activation and its versatile application in wastewater reclamation.

Thermoplastic Vulcanizates with an Integration of High Wear-Resistant and Anti-Slip Properties Based on Styrene Ethylene Propylene Styrene Block Copolymer/Styrene Ethylene Butylene Styrene Block Copolymer/Solution-Polymerization Styrene-Butadiene Rubber.

Distinguished from traditional vulcanized rubber, which is not reusable, thermoplastic elastomer (TPV) is a material that possesses both the excellent resilience of traditional vulcanized rubber and the recyclability of thermoplastic, and TPVs have been widely studied in both academia and industry because of their outstanding green properties. In this study, new thermoplastic elastomers based on solution polymerized styrene butadiene rubber (SSBR) and thermoplastic elastomers (SEPSs/SEBSs) were prepared by the first dynamic vulcanization process. The high slip resistance and abrasion resistance of SSBR are utilized to improve the poor slip resistance of SEPSs/SEBSs, which provides a direction for the recycling of shoe sole materials. In this paper, the effects of different ratios of the rubber/plastic phase (R/P) on the mechanical properties, rheological properties, micro-morphology, wear resistance, and anti-slip properties of SSBR/TPE TPVs are investigated. The results show that the SSBR/TPE TPVs have good mechanical properties. The tensile strength, tear strength, hardness, and resilience of the TPVs decrease slightly with an increasing R/P ratio. Still, TPVs have a tensile strength of 18.1 MPa when the ratio of R/P is 40/100, and this reaches the performance of the vulcanized rubber sole materials commonly used in the market. In addition, combined with microscopic morphology analysis (SEM), it was found that, with the increase in the R/P ratio, the size of the rubber particles gradually increased, forming a stronger crosslinking network, but the rheological properties of TPVs gradually decreased; crosslinking network enhancement led to the increase in the size of the rubber particles, and the increase in the size of rubber particles made the material in the abrasion of rubber particles fall easily, thus increasing its abrasion volume. Through dynamic mechanical analysis and anti-slip tests, when the R/P ratio was 40/100, the tan δ of TPVs at 0 °C was 0.35, which represents an ordinary vulcanized rubber sole material in the market. The viscoelasticity of TPVs increased with the increase in the R/P ratio, which improved the anti-slip performance of TPVs. SSBR/TPE TPVs are expected to be used in footwear and automotive fields due to their excellent abrasion resistance and anti-slip performance.

Predicting glass transition temperature of polymers by combining molecular dynamics simulations and machine learning techniques

Polymeric materials, valued for their cost-effectiveness and ease of processing, play a pivotal role in diverse applications. Among them, solution polymerized styrene butadiene rubber (SSBR) stands out with low rolling and wet skid resistance, ideal for eco-friendly tire. The glass transition temperature (Tg) is an important parameter in determining the performance of SSBR, which is time-consuming to test with conventional experiments. In recent years, machine learning (ML) has emerged as a useful tool in materials science. In this study, all-atom molecular dynamics (AAMD) simulation provided the foundational training data. Subsequently, ML techniques are utilized to efficiently predict SSBR’s Tg based on its content of four key structural components. To address the challenge of limited sample sizes, the innovative integration of Ordinary Kriging (OK) from geostatistics and Nearest Neighbor Interpolation (NNI) was employed to compute label values for interpolation points, which surpasses previous studies relying solely on NNI. Comparative analysis of four ML models (XGBoost, Ridge, LASSO, and SVR) reveals XGBoost’s superior performance in handling this nonlinear problem, with consistently high R2 and low RMSE scores. Through 900 repeated experiments, the model demonstrates robustness, maintaining an average R2 of approximately 0.9703. Ultimately, the novel integrated ML approach (NNI-OK-XGBoost) was proposed. Furthermore, four new combinations of structural unit content were evaluated using both ML predictions and AAMD simulations. The validation confirms the efficiency and accuracy of this method in predicting SSBR’s Tg across varying composition ratios within a specified composition space. This work presents a viable solution for accurately and rapidly predicting the Tg of polymeric materials, particularly in scenarios with limited sample sizes.

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.

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.

Comparing Degradation Mechanisms, Quality, and Energy Usage for Pellet- and Filament-Based Material Extrusion for Short Carbon Fiber-Reinforced Composites with Recycled Polymer Matrices

Short carbon fiber (sCF)-based polymer composite parts enable one to increase in the material property range for additive manufacturing (AM) applications. However, room for technical and material improvement is still possible, bearing in mind that the commonly used fused filament fabrication (FFF) technique is prone to an extra filament-making step. Here, we compare FFF with direct pellet additive manufacturing (DPAM) for sCF-based composites, taking into account degradation reactions, print quality, and energy usage. On top of that, the matrix is based on industrial waste polymers (recycled polycarbonate blended with acrylonitrile butadiene styrene polymer and recycled propylene), additives are explored, and the printing settings are optimized, benefiting from molecular, rheological, thermal, morphological, and material property analyses. Despite this, DPAM resulted in a rougher surface finish compared to FFF and can be seen as a faster printing technique that reduces energy consumption and molecular degradation. The findings help formulate guidelines for the successful DPAM and FFF of sCF-based composite materials in view of better market appreciation.

The Effect of the Temperature–Humidity Coupling Cycle on the Performance of Styrene Butadiene Styrene Polymer-Modified Asphalt Mastic

To study the variation laws and effects of asphalt mastic under the cooperative interaction of different temperatures and humidities, cyclic conditions for different temperature ranges were set to conduct indoor experimental simulations of thermal–humidity coupling cycles. Firstly, the macroscopic performance changes in styrene butadiene styrene polymer (SBS)-modified asphalt mastic were evaluated by the penetration test, softening point test, ductility test, Brookfield rotational viscosity test, and double-edge notched tensile (DENT) test; then, the mechanism of performance changes was explored from the perspective of chemical composition by combining this with Fourier transform infrared spectroscopy (FTIR). The research results show that with the increase in thermal–humidity coupling cycles, SBS-modified asphalt mastic exhibited aging phenomena such as hardening and embrittlement, and its macroscopic performance deteriorated; under the same test conditions, the interval with a higher temperature difference had a greater impact on the performance of the mastic; the sulfoxide index (IS=O) of SBS-modified asphalt mastic increases after thermal–humidity coupling cycles, while the isoprene index (IB) decreases.

Thermo-rheological behaviour of styrene-butadiene-styrene, hard plastics with or without graphene oxide modified bitumens

With the increase in traffic volume and heavy vehicles, as the changes in climatic conditions, in recent years the design of the road surface has completely changed because it has to guarantee the suitable performance of the pavement. To this end, in recent decades, modifiers have been introduced into the bitumen and, currently, the most performing modifier is SBS (styrene-butadiene-styrene) polymer, but in recent years the investigation on the so-called green additives, obtained from recycled materials or of natural origin is growing. The study intends to investigate, from a rheological point of view, the possibility of using waste hard plastics also in combination with graphene oxide because considered a promising material for new binder generation. For this purpose, the influence that hard plastics, with or without graphene oxide addition, have on the bitumen performance compared to standard SBS-modified bitumens has been studied. The comparison has shown that the plastomeric additive can improve the rheological properties, in the intermediate and high in-service temperature region, while the graphene oxide addition acts on the transitions from viscoelastic to viscous material at high temperature; nevertheless, the aging reduces the effect. In addition, it was found that 4 %w/w of hard plastics improve the performance of bitumen and the rheological properties are not affected by the influence of aging.

Modelling Fatigue Crack Growth in High-Density Polyethylene and Acrylonitrile Butadiene Styrene Polymers.

Prior studies into fatigue crack growth (FCG) in fibre-reinforced polymer composites have shown that the two methodologies of Simple-Scaling and the Hartman-Schijve crack growth equation, which is based on relating the FCG rate to the Schwalbe crack driving force, Δκ, were able to account for differences observed in the measured delamination growth curves. The present paper reveals that these two approaches are also able to account for differences seen in plots of the rate of crack growth, da/dt, versus the range of the imposed stress intensity factor, ΔK, associated with fatigue tests on different grades of high-density polyethylene (HDPE) polymers, before and after electron-beam irradiation, and for tests conducted at different R ratios. Also, these studies are successfully extended to consider FCG in an acrylonitrile butadiene styrene (ABS) polymer that is processed using both conventional injection moulding and additive-manufactured (AM) 3D printing.

Rheological and microstructural properties of nano-composite bitumen modified by nano-alumina and low-SBS content

This study explores a new nanocomposite-modified bitumen (NCMB) that could be more cost-effective and environmentally friendly than current options. It achieves this by combining a lower amount of styrene butadiene styrene (SBS) polymer with nano-alumina, aiming to improve performance at high and moderate temperatures. This innovative material aims to overcome the performance limitations of traditional polymer-modified bitumen (PMB). Moreover, this NCMB, which uses less modifier (SBS) and nano-alumina, paves the way for more economical and eco-friendly roads, leading to significant fuel savings. The new NCMB was prepared by mixing various nano-alumina contents (2, 3, 4, and 5 % by weight of bitumen) with low-SBS content (2.5 % by weight of bitumen) PMB. Multiple stress creep recovery (MSCR) and linear amplitude sweep (LAS) tests, further the Superpave standard method, were used to assess the rutting and fatigue cracking resistance of PMB and NCMBs. Field emission scanning electron microscopy (FESEM) with elemental analysis by energy dispersive X-ray spectroscopy map (EDS) techniques and Fourier-transform infrared spectroscopy (FTIR) was used to investigate the microstructural and elemental characteristics of NCBBs. The results demonstrated that adding nano-alumina to low-SBS content PMB significantly enhanced both the storage stability and its durability over time (i.e. aging resistance) of the NCMBs. The MSCR test results showed that samples with 5 % nano-alumina had a rutting resistance higher than the PMB, up to 31 %. The NCMB samples with 4 % nano-alumina demonstrated a significant improvement in fatigue resistance of up to 67 %. The FTIR results revealed a 64 % improvement in aging resistance for NCMBs containing 3 % nano-alumina compared to the PMB. The storage stability values increased for all NCMB types and reached 62 % for the samples with 5 % nano-alumina. Overall, adding nano-alumina to low-SBS content PMB led to a remarkable improvement of rheological properties at intermediate and high temperatures and a stable system under storage conditions with high anti-aging resistance.

COMPATIBILITY STUDY OF HYDROCARBON RESINS WITH RUBBER COMPOUNDS FOR TIRE APPLICATIONS

ABSTRACT The addition of hydrocarbon resins to rubber compounds has a significant impact on their properties such as wet grip and rolling resistance. These performance characteristics have a strong correlation with the compatibility of the resin with the rubber matrix. Incompatible resins can cause excessive broadening of the damping curve, which results in poor rolling resistance. Compatibility, however, allows maximization of wet grip while minimizing the effect on rolling resistance. Compatibility is promoted by lower resin molecular weight and structural similarity to the polymers being blended. In this study, a method based on the Fox equation has been developed to quantitatively characterize the compatibility between resin and natural rubber (NR), a binary system. The dynamic shear rheometer (DSR), a tool new to the tire industry, is used to investigate the interaction between resin and two rubbers (i.e., a ternary system of NR–butadiene rubber [BR]–resin and solution polymerized styrene–butadiene rubber [SSBR]–butadiene rubber [BR]–resin), with a specific emphasis on resin partitioning among rubber blends. In addition, the DSR is applied to assess the Tg shift and tangent delta peak height, providing insight into the compatibility between rubbers and resin. A curve-fitting model was developed for the SSBR–BR–resin system to depict the relationship between these two parameters and the physical and chemical properties of resins, with the selection of resins featuring different degrees of aromaticity, Tg, and molecular weight. The findings indicated that higher Tg increased aromaticity and that lower molecular weight of the resin resulted in an elevated Tg shift in the blend, while lower molecular weight led to an increase in the tangent delta peak height. Our findings supply insight into the performance of rubber–resin blends and introduce a new screening tool for characterizing these blends in their green state.

Performance evaluation of 3D-printed ABS and carbon fiber-reinforced ABS polymeric spur gears

Acrylonitrile butadiene styrene (ABS) polymer and carbon fiber reinforced acrylonitrile butadiene styrene (CF/ABS) spur gears were 3D-printed using fusion deposition modeling (FDM) with different fillet radii of 0.25, 0.50, and 0.75 mm. The performance of the fabricated gears was studied with the effect of fillet radius on varying load and speed conditions. The thermal properties of the gears were also investigated. The results indicated that 3D-printed CF/ABS spur gear exhibited better performance than the pure ABS. The 3D-printed CF/ABS gear with fillet radius of 0.25 mm recorded the highest wear and thermal stresses. However, the optimum performance was exhibited by the gear sample with highest fillet radius of 0.75 mm. Repeated gear tooth loading during service caused an increase in gear temperature due to the hysteresis and friction. Using optical microscopy, the tooth structures of both 3D-printed ABS and CF/ABS spur gears were analyzed before and after loading conditions to establish their failure mechanism. Evidently, various applications of the FDM 3D-printed spur gears depend on their different performances under loads and operating speeds. The methods and findings of this work can be regarded as helpful for future related work related to cellulosic reinforcing particles in a polymer matrix.

Evaluating and Comparing Flexure Strength of Dental Models Printed Using Fused Deposition Modelling, Digital Light Processing, and Stereolithography Apparatus Printers.

The introduction of three-dimensional (3D) printing in dentistry has mainly focused on applications such as surgical planning, computer-guided templates, and digital impression conversions. Additive manufacturing (AM), also known as 3D printing, involves layering resin material sequentially to construct objectsand is gaining recognition for its role in creating custom-made medical appliances. The field of orthodontics has also embraced this technological waveand with the advent of cost-effective printers and biocompatible resins, 3D printing has become increasingly feasible and popular in orthodontic clinics. The limitations of traditional plaster models may have prompted the emergence of 3D-printed models, but it led to enhancing treatment planning and device fabrication, particularly in orthodontics. Notable desktop printing technologies include fused deposition modelling (FDM), digital light processing (DLP), and stereolithography (SLA), each employing distinct methods and materials for fabricating appliances. Evaluating mechanical properties, like flexure strength, is crucial to determine the material's ability to withstand bending forces and thus prove useful in fabricating thermoformable appliances, surgical templates, etc. This study aims to assess the flexure strength of 3D-printed models using FDM, DLP, and SLA technology, providing insights into their suitability as replacements for conventional models and shedding some light on the durability and sustainability of 3D-printed models. Cuboids measuring 20 x 5 x 2 mm were cut from models, creating 10 samples per printer group. These samples underwent flexure strength testing using a three-point bending system in a universal testing machine. The FDM group exhibited the highest flexure strength at 69.36 ± 6.03 MPa, while the DLP group showed the lowest flexure strength at 67.47 ± 20.58 MPa. The results can be attributed to the differences in resin materials used for fabrication, with FDM using acrylonitrile butadiene styrene (ABS) polymer and SLA/DLP using polymethyl methacrylate (PMMA), and also to the variation in their printing mechanism. The findings affirm the suitability of FDM models for orthodontic applications, suggesting enhanced efficiency and reliability in clinical practices.

Performance and Lifecycle of Hot Asphalt Mix Modified with Low-Percentage Polystyrene and Polybutadiene Compounds

The paper investigates the improvement of bitumen mixture fatigue resistance and the rutting performance by using a specific low percentage of a styrene–butadiene–styrene (SBS) polymer, which contains polystyrene and polybutadiene compounds. A Fourier transform infrared (IR-FT) spectroscopy of the SBS polymer used in following test was carried out to ascertain the polybutadiene and polystyrene compound ratio, which may affect the modificant properties. Unmodified, low-percentage modified SBS, and common polymer-modified bitumen (PMB) as a reference were tested to ascertain the properties, fatigue resistance, and the rutting performance. The test results of the low-percentage modification with SBS are compared against unmodified mixtures and standard PMB mixtures. Finally, a simulation of the practical application was performed using the HDM-4 software (version 2.0), where the material research findings, with an emphasis on the rutting performance, were translated into the pavement performance with a varying binder course layer under simulated traffic conditions. Lifecycle analysis, with a focus on emissions production (CO2, SO2, and NOx) during pavement operation, was conducted for pavements with unmodified, low-percentage modified SBS, and standard PMB binder courses. The lifecycle analysis showed that a 3% modification of the binder course with the SBS polymer can extend the rutting parameter pavement lifecycle by approximately 34.5%, which is about half of the extension provided by the standard PMB modification. The resulting improvement in the pavement serviceability translated to a 9% reduction in CO2 and SO2 emissions and a 7.2% reduction in NOx emissions over a 20-year period.

The role of polymer modification in mitigating ‘sunburn’ damage on asphalt roads

Asphalt roads suffer from ageing throughout their service life due to exposure to ultraviolet light (UV). The aim of this study is to determine the role of polymers such as ethylene vinyl acetate (EVA), styrene butadiene styrene (SBS) and crumb rubber from end-of-life tyres (CR) in protecting bitumen against the damage caused by UV radiations when roads are exposed to sunlight. One unmodified bitumen and four polymer-modified commercial binders were exposed to a filtered xenon-arc light for 10, 20 and 30 days before being tested. Overall, SBS modified binders were less damaged by UV exposure, followed by CR and EVA modified binders. More specifically, SBS provided the best cracking resistance to the binder after ageing compared to conventional unmodified bitumen, followed by CR. EVA did not improve the cracking resistance of the binder. A deep chemical analysis of the photo-oxidation mechanism of polymer-modified binders revealed that SBS is more effective in reducing the formation of carbonyls and aromatics in aged bitumen compared to CR and EVA. The 3D network formed by SBS polymer chains in bitumen was found to be more resistant to oxidation than CR and EVA chains, hence providing a superior UV resistance to SBS-modified binders. Overall, CR seems to provide a sustainable alternative to conventional polymers since using CR for bitumen modification would reduce landfilling of tyres while increasing roads service life and reducing maintenance costs.

An investigation on the toughening behavior and morphology of acrylonitrile butadiene styrene/polybutylene terephthalate blends reinforced by carbon nanotubes

Acrylonitrile butadiene styrene (ABS) and polybutylene terephthalate (PBT) polymers are widely exploited polymers in the plastics industry. In this research, PBT polymer is added into ABS polymer as a second phase due to its good fluidity and some superior mechanical characteristics. Carbon nanotubes (CNTs) are added as a reinforcement into the ABS/PBT polymer blend (80/20). Standard samples of mechanical tests including tensile, flexural, and impact were made by injection molding and standard samples of fracture tests were made by hot press method. The essential work of fracture (EWF) method was used to check fracture toughness. The presence of PBT into ABS improved its tensile and flexural strength while it diminished the impact strength and fracture toughness of ABS. The addition of carbon nanotubes into ABS/PBT blends increased its tensile and flexural strength, impact resistance as well as fracture toughness. The results of microscopic tests demonstrate a relatively uniform distribution of carbon nanotubes in the polymer blend. In addition, the morphological observations illustrate a rather proper adhesion between carbon nanotubes and the polymeric matrix. As importantly, investigations on the fractured sections of fracture specimens revealed that the nanocomposites containing CNTs have a tendency toward a ductile failure in comparison with ABS/PBT polymer blend.

Investigating the unique entropy-elasticity of polymer modified asphalt

Crafting Styrene-Butadiene-Styrene (SBS) polymer into the bitumen can notably improve the elastic response of the polymer modified bitumen (PMB), which will significantly enhance the overall performance of bituminous pavement. But the molecular mechanism of the PMB’s unique entropy elasticity has not been fully understood yet. The prominent entropy-elasticity of SBS polymer modified asphalt was investigated in this study. To do so, Fourier Transform Infrared (FTIR), Gel Permeation Chromatography (GPC) and Dynamic Mechanical Analysis (DMA) were conducted to investigate the molecular modification mechanism of PMB. Afterwards, polymer molecular model with a polymerization degree over 2000 is constructed and dynamic simulation is conducted to reveal the mesoscopic mechanism of SBS polymer’s entropy elasticity. As for macroscopic evaluation, a series of creep and recovery tests associated with different testing temperatures (10 °C to 100 °C with a 6 °C gap), recovery times (0.01 s, 0.1 s, 1 s, 4 s and 9 s) and SBS dosages (0 %, 2.5 %, 4.2 %, 7.5 %) were carried out to characterize the elasticity of various PMBs. The results show that plain bitumen mainly shows energy-elasticity, which is small, instantaneous and highly temperature-dependent, while PMB mainly shows entropy-elasticity, which is strong, delayed and less temperature-dependent. Under the condition of low temperature and short recovery time, the bitumen molecules freeze and prevent the SBS polymer to demonstrate its entropy-elasticity, hence the energy-elasticity dominates. Higher temperatures and long recovery time render the SBS molecule more time to relax and thus the entropy-elasticity dominates. The predominant influence of entropy-elasticity in PMA leads to a unique increasing recovery rate within a specific high-temperature range. This phenomenon can be utilized as a fingerprint approach for the identification of the entropy-elasticity and polymer modification.

The Influence of Single-Walled Carbon Nanotubes on the Aging Performance of Polymer-Modified Binders.

The use of polymer-modified binders in asphalt concrete makes it possible to increase the efficiency and durability of highways. However, at present, there is an important and unresolved problem in this area, making it impossible to fully exploit the potential of modified binders. This is a tendency of aging processes that leads to the premature destruction of the pavement. In many literary sources, it is reported that reasons are related to the peculiarity of the chemical composition and occur at the submicron level. Therefore, the influence of single-walled carbon nanotubes has been studied for a better understanding of aging processes. The aging processes of the RTFOT (rolling thin film oven test) and PAV (pressure aging vessel) modified with SBS (styrene-butadiene-styrene) polymer, single-walled carbon nanotubes, and waste industrial oil were simulated in a laboratory furnace. Microstructural features were studied using the method of infrared spectral analysis. The dependences of viscoelastic properties on the component composition of binders were investigated. The optimal content of single-walled carbon nanotubes (0.001%), SBS (styrene-butadiene-styrene) polymer (3.5%), and waste industrial oil (4%) in the binder composition was established, which synergistically improved the performance of the modified binder from PG (52-22) (performance grade) to PG (64-34). It was established that single-walled carbon nanotubes provide improvement in the durability parameter ∆Tc binder by 150%, improved relaxation properties at low temperatures, and resistance to fatigue damage.

Qualitative Evaluation for Asphalt Binder Modified with SBS Polymer

Solutions for safer, more durable infrastructure are required in light of increasing traffic and severe weather in Iraq. The most significant road conservation and maintenance challenges are the pavement's low resistance to dynamic loads and short service life. As a result, vast sums of money are spent annually to enhance the road service capacities in Iraq. Thermoplastic electrometric polymers for bitumen modification create long-lasting, cost-effective roadways. This study aims to determine how the mechanical properties of neat asphalt binder change when styrene butadiene styrene (SBS) is added as a modifier. The current research investigates adding three percentages of SBS (3, 5, and 7% of the weight of bitumen). Both neat and polymer-modified bitumen (PMB) were subjected to a series of physical laboratory and Superpave tests, including a dynamic shear rheometer tester (DSR) and a storage stability test. In addition, a chemical analysis test was conducted to identify any change in the neat binder chemical composition due to the addition of SBS polymer. The results indicated that 5% of SBS polymer was the optimum addition percentage to the local asphalt in Iraq. Additionally, it reduced the susceptibility of bitumen to temperature changes and enhanced its characteristics in all laboratory tests. The obtained PMB significantly improved rutting and fatigue factors compared to the neat asphalt binder. Based on the DSR tester and the storage stability test, the ratio of 5% SBS met the requirements of class PG76-10, used in the central and southern governorates of Iraq. Using SBS polymer on the surface course in Iraq reduces road damage due to the scorching summer sun, reduces the likelihood of rutting and fatigue cracking, and works well in hot regions, resulting in roads that last longer, provide comfortable riding, and require less maintenance.