Butadiene Styrene Research Articles

Effects of photodegradation performance with PLA‐containing samples on double injection molding

AbstractThe influence of different overlay layers (ABS, PC, and PLA) is investigated on the photodegradation behavior of poly(lactic acid) (PLA)‐containing samples in double injection molding, and PLA/PLA samples serve as the control group. In terms of microstructure, an analysis is conducted on the chemical structure, thermal performance, crystallinity, and molecular weight of the base layer of samples. The carbonyl index and molecular weight of the base layer of PLA/PLA samples decrease rapidly, and the trend of crystallinity change is also fast. Among them, the number of molecular chain scissions decreases to 0.61, and the crystallinity increases to a maximum of 17.93%, which indicates that the photodegradation degree of the base layer of PLA/PLA samples is greater than that of the other two samples. The microscopic surface morphology change of the base layer of three PLA‐containing samples is analyzed. The base layer of PLA/PLA samples becomes rougher after 600 h of UV degradation. Meanwhile, compared with other PLA‐containing samples, the percentage of tensile strength loss of PLA/PLA samples is higher, decreasing by 16.64%. In summary, using acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) materials as overlay layers for double injection molding can mitigate the photodegradation of the base layer of PLA‐containing samples in double injection molding.

A High‐Sensitive Rubber‐Based Sensor with Integrated Strain and Humidity Responses Enabled by Bionic Gradient Structure

AbstractReal‐time detection of different physiological characteristics is crucial for human physical and mental health. A detection system with multimodal sensing capability, high sensitivity, excellent mechanical properties, and environmental stability is highly desirable, but it is still a great challenge. Inspired by the structural gradient of biological tissues, a multifunctional sensor based on carboxylic styrene butadiene rubber (XSBR) and sodium polyacrylate (PAANa) non‐covalently modified MXenes is prepared in this study, in which the MXenes exhibit a gradient distribution and simultaneously formed an orientation arrangement at the bottom of the matrix through the formation of hydrogen bonding interactions with PAANa. The material shows a considerable stretchability of 244% and strength of 7.67 MPa, high electrical conductivity of 55.40 S m‒1, low percolation threshold of 2.48 wt%, and excellent response to strain (gauge factor of 906.7 within 98% strain) and humidity (relative resistance change of 530% within 11–93% relative humidity). Based on the superior performances of the XSBR/PAANa/MXene composite, an integrated detection system is designed to accurately detect respiration and body movements at various scales. This work provides a new perspective for the development of a novel biomimetic functional material for sensor applications.

Unveiling the physico‐mechanical properties of kenaf yarn fiber‐reinforced acrylonitrile butadiene styrene composites: Effect of quasi‐isotropic lay‐up sequences

AbstractThe rapid advancement of polymer composites, particularly those reinforced with hybrid kenaf, has positioned them as viable structural materials across diverse industries such as automotive, defense, aerospace, marine, construction, and naval. Despite their growing popularity, recent advances in kenaf yarn‐reinforced thermoplastic acrylonitrile butadiene styrene (ABS) composites for structural applications need more comprehensive coverage in the literature. This article addresses this gap by critically examining the influence of quasi‐isotropic stacking orientation on water absorption, flexural strength, and impact properties in kenaf yarn fiber‐reinforced ABS composites. Prepared using hand layup and compression molding techniques, the composites featured varying stacking orientations, including 0°/0°/0°/0°, 0°/90°/0°/90°, −45°/90°/0°/45°, 90°/−45°/0°/45°, 90°/0°/45°/−45°, and 0°/45°/−45°/90° for kenaf yarn reinforced ABS. The findings reveal that the 0°/45°/−45°/90° configuration offers the best overall mechanical properties and water penetration resistance among quasi‐isotropic stacking sequences, exhibiting low water uptake and higher tensile and flexural strengths of 35.3 and 85.4 MPa, respectively, compared to other sequences. This suggests that incorporating ±45° plies contributes to a balanced distribution of mechanical strength and modulus across different directions, making the 0°/45°/−45°/90° configuration ideal for high‐strength structural applications in kenaf yarn/ABS composites.Highlights Fiber stacking orientation is the key factor affecting the mechanical performance of kenaf‐based composites. Using the hand layup technique, six stacking orientations (0°/0°/0°/0°, 0°/90°/0°/90°, −45°/90°/0°/45°, 90°/−45°/0°/45°, 90°/0°/45°/−45°, and 0°/45°/−45°/90°) were employed to create kenaf fiber‐reinforced ABS composites. A quasi‐isotropic sequence of 0°/45°/−45°/90° allows the least water penetration due to the strategic placement of ±45° plies in the middle layers of composites. 0°/45°/−45°/90° configuration offers the best flexural and tensile properties due to better force distribution within the ±45° plies in the middle layers. Under surface morphological analysis, the optimal fiber stacking sequence contributes to fewer voids and fiber pull‐outs.

Preparation and performance of biaxially stretched CNT-SBS/POE flexible strain sensor with a double percolation structure

Wearable flexible strain sensors have prospective application prospects in human motion monitoring, human-computer interaction, and information transmission. However, facilely manufacturing flexible strain sensors with a high sensitivity and extended sensing range remains challenging. Herein, a flexible strain sensor with a double percolation structure was prepared through simple melting mixing and biaxial stretching. To this end, carbon nanotubes (CNTs) filled styrene butadiene styrene (SBS) and polyolefin elastomer (POE) were employed as the conductive and insulating phases, respectively. The effects of biaxial stretching on sensor performance were systematically studied. During biaxial stretching, the as-obtained CNT-SBS/POE nanocomposites with double percolation structure exhibited better processing performance and stability than conventional CNT-SBS binary composites. Biaxial stretching results in better dispersion and planar orientation of CNTs in polymers, improving the sensing property of strain sensors. The optimized stretching ratio of double percolation structured composites was determined as 1.5, with 3 wt% CNT-SBS/POE sensor exhibiting high sensitivity (gauge factor = 7501.69) over a wide strain monitoring range (0–300% strain). Additionally, the flexible strain sensors could monitor physiological activities and information transmission with good reliability, thereby promising for human-machine interaction, wearable, and medical monitoring.

Effect of filler surface treatment on the physico-mechanical properties of filler/styrene-butadiene rubber nanocomposites

In the present work, the effects of various filler types and content on the characteristics and properties of styrene-butadiene rubber (SBR) were studied. This study prepared SBR filled with different fillers: kaolin, metakaolinite, synthetic zeolite Na-A, alumina (Al2O3) nanoparticles, and hybrid filler (synthetic zeolite Na-A/Al2O3). The silane coupling agent 3-aminopropyltriethoxysilane (APTES) was employed to treat the surface with fillers. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were used to determine the surface morphology. The results demonstrated that fillers improved the physicomechanical properties. Tensile strength and elongation at break (%) in composites containing synthetic zeolite Na-A increased by up to 158.6% at 3 phr and 100% at 2 phr, respectively. The results showed that the surface properties displayed by SEM analysis indicated a good distribution of filler particles. Also, the rubber compound’s resistance to organic solvents such as toluene was improved, as evidenced by swelling properties; the swelling ratio decreased by 17.5% while the crosslink density increased by 42.6% at 5 phr Al2O3/synthetic zeolite Na-A. The constants of the various hyperelastic models that explain the behavior of the composite materials under study were determined, and their predictions of the experimentally obtained stress-strain curves were compared. The study’s experimental findings will be helpful for several industrial uses, including an extender in water-based paints, rubber fillers, ceramic materials, paper fillers, and coating pigments.

معجل ثالثي مستدام لفلكنة الكبريت لمطاطي ال NR و ال SBR من مستخلص اوراق شجرة

تم تحضير معجل جديد, طبيعي, رخيص, ومتاح يستخدم في انظمة فلكنة المطاط الطبيعي NR)) و مطاط الستايرين بيوتادايين ((SBR وقد تم تحضير هذا المعجل من المخلفات الزراعية. حيث تم اضافة مسحوق مجفف لمستخلص من اوراق شجرة الكينوكاربس لانسيفوليوس Conocarpus lancifolius بالنسب المئوية التالية: 0.5, 1.0, 1.5, 2.0) wt%) الى العجينة الرئيسية لمطاطي ال NR و ال SBR والتي تحتوي على معجلات البنزوثايوزول (MBT, MBTS). تم اختيار مستخلص CLLE)) نظرًا لاحتوائه على مركبات الفلافونويد, السابونين و الفينولات داخل هيكلها، مما يعزز الترابط الهيدروجيني (H-bond) كرابطة ثانوية ، والتي بدورها تعزز معدل المعالجة. اظهرت النتائج قابلية مستخلص CLLE)) على تعجيل (curing systems)نظامي الفلكنة المذكورين حيث كان التركيز الامثل مع مطاط ال 0.5( pphr) SBR والتركيز الامثل لمطاط ال NR 1 (pphr) . وكان تأثير هذا المستخلص على نظام معالجة مطاط NR اكبر من مطاط ال SBR حيث انخفض زمن الانضاج الامثل Tc90 لمطاط ال SBR بمقدار (2.42 %) في حين انخفض بمقدار 17.74 % لمطاط ال NR , اما بالنسبة لمؤشر معدل النضوج (CRI) فقد ازداد في مطاط ال SBR بمقدار 5.9 % فقط, في حين انه ازداد بمقدار 24.83 % لمطاط ال NR. بالإضافة الى ذلك فان اضافة مستخلص CLLE)) قد عملت على تقليل زمن الاحتراق (ts2) ولكلا المطاطين. وكانت قيم ال ts2 لعينات مطاط ال SBR اكبر من قيم ال ts2 لعينات مطاط ال NR. كما بينت النتائج ان اضافة CLLE)) لم تؤثر على قيم مقاومة الشد وكان هناك انخفاض طفيف في قيمة الصلابة وزيادة في معامل الاستطالة عند (300%) وزيادة في قيم الاجهاد و الانفعال قبل الفشل. أدت إضافة CLLE إلى زيادة معدلات المعالجة بسبب احتوائها على مكونات نشطة (الفلافونويد والسابونين والفينولات) ، والتي شجعت على استخدام هذه المنتجات المرنة للتطبيقات الحيوية وتعمل كعامل اقتران للبوليمرات المحبة للماء والطارئة للماء.

A NOVEL SBS COMPOUND VIA BLENDING WITH PS-B-PMBL DIBLOCK COPOLYMER FOR ENHANCED MECHANICAL PROPERTIES

ABSTRACT Styrene–butadiene–styrene (SBS) rubbers are one of the most frequently used thermoplastic elastomers globally. The upper operating temperature of SBS is limited by the glass transition temperature (Tg) of poly(styrene) (PS), circa 100 °C. This study demonstrates a noteworthy enhancement in the properties of SBSs by introducing a diblock copolymer consisting of styrene and α-methylene-γ-butyrolactone (α-MBL). Polymers derived from α-MBL exhibit exceptional thermal stability, attributable to a Tg of 195 °C. Notably, α-MBL, also recognized as Tulipalin A, is a biorenewable compound naturally found in tulips. This investigation encompasses both crosslinked and noncrosslinked blends of poly(styrene)-block-poly(α-methylene-γ-butyrolactone) diblock copolymer (PS-b-PMBL) and poly(styrene)-block-poly(butadiene)-block-poly(styrene) triblock copolymer, within the 0–20 wt% PS-b-PMBL range. Thorough examination using thermal analysis and linear shear rheology reveals that all blends surpass the properties of their pure SBS counterparts. Specifically, blending at 200 °C induces crosslinking between the polymers, yielding heightened Young’s modulus and complex viscosity, thereby resulting in a robust and rigid material compared with noncrosslinked blends. For noncrosslinked blends, an increase in strength is observed while maintaining commendable rubbery properties. Notably, the noncrosslinked blends permit the recycling of components (SBS and PS-b-PMBL) through the redissolving of rubber in tetrahydrofuran. These findings present a promising avenue for the enhancement of rubbers through the incorporation of biorenewable compounds.

Study of the active anti-icing properties of modified biological antifreeze protein micro-surfacing

The accumulation of snow and ice on the surface of roadways can threaten driving safety, which is a major pain point in winter. To address the issue of pavement icing, this paper researched the biological antifreeze protein (AFP) filler, which was then mixed with a portion of mineral powder to create a blend. This blend was further combined with emulsified asphalt modified by a combination of styrene-butadiene rubber (SBR) and waterborne epoxy resin (WER) to produce a micro-surfacing mixture with active anti-icing capabilities. The road performance tests were conducted to assess whether the anti-icing micro-surfacing mixture’s road performance was affected. Subsequently, improved and innovative anti-icing tests were conducted to evaluate the anti-icing performance of the anti-icing micro-surfacing. The anti-icing tests encompassed freezing tests, ice-melting and snow-melting tests, active de-icing simulation tests, and ice adhesion force tests. The road performance tests indicate that the incorporation of antifreeze filler enhances the resistance of the micro-surfacing mixture against water erosion during freeze-thaw cycles, with a minimal impact on rutting resistance and abrasion resistance. The freezing test demonstrates the excellent active antifreeze function of the anti-icing micro-surfacing. Furthermore, the ice-melting and snow-melting test reveals that the anti-icing micro-surfacing effectively speeds up the melting process of snow and ice on the surface of roadways. The active de-icing simulation test and adhesion test confirm that the anti-icing micro-surfacing significantly accelerates the rate of active de-icing. Overall, the anti-icing micro-surfacing demonstrates a significant active anti-icing effect while maintaining its road performance capabilities.

Utilization of Bamboo Roots as Reinforcing Composite Materials for Light Vehicle Dashboards

Bamboo roots are residual material from the utilization of bamboo trees’ waste. Bamboo roots utilize in engineering by making new materials in the form of composites. Bamboo roots are easy to get, and getting bamboo root fiber is relatively easy compared to getting bamboo stem fiber. Bamboo root fibers are used as reinforcement in composites with resin binders and catalysts as hardeners. The composite made by mixing the composition consists of 10% bamboo root fiber, 89% resin, and 1% catalyst from the weight of the specimen. This composition uses three variations of fiber direction; straight, random, and woven fiber—each variation tests tensile strength, impact, and bending strength. Those three test results show that the highest values come from the woven fiber, which are 21.04 MPa from the tensile strength, 0.0693 J/mm2 from the impact value, and 34.789 MPa from the bending strength value. The test result found that applying bamboo roots composite material suits dashboard material for light vehicles (cars and motorcycles). This test result meets the standard material for dashboard vehicles based on plastic material data ABS (Acrylonitrile butadiene styrene). This research on natural fiber composite material is novel and valuable as a waste utilization solution for engineering materials.

Prediction surface roughness of 3D printed parts using genetic algorithm optimized hybrid learning model

The final product of additive manufacturing (AM) or 3D printing critically depends on the surface quality. An experimental study on the 3D printed intake manifold flange using acrylonitrile butadiene styrene (ABS) material was executed by varying the four process parameters. A fused deposition modeling (FDM) based 3D printer was used to fabricate the flanges. The association between the parameters and the surface roughness of printed ABS flanges was investigated. A feed forward neural network (FFNN) model trained on particle swarm optimization (PSO) optimized with a genetic algorithm (GA) was used to estimate the surface roughness. A Box-Behnken design (BBD) with printing parameters at three levels was used, and 25 parts were fabricated. The suggested model demonstrated a coefficient of determination (R2) of 0.9865 on test values, mean of root-mean-square-error (RMSE) of 0.1231 after 500 times training for generalization. And also mean of overfitting factor is 0.7110. This means that the suggested system could generalize. Comparing the results from the suggested model and ANN, the suggested hybrid model outperformed ANN in predicting the surface roughness values with no overfitting. This suggests that GA optimized PSO based FFNN may be a more suitable method for estimating product quality in terms of surface roughness.

An impedance transformer for UHF RFID and WiFi cross‐technology communication‐based tourism crowd counting

AbstractThis letter proposes a novel cross‐shaped structure‐based parallel coupled line transformer and its application to tag antenna for 920‐MHz radio frequency identification (RFID) and 5‐GHz WiFi Cross‐Technology Communication (CTC). This transformer can be tuned by some lumped capacitors and the equivalent transmission line length for high order harmonic matching. The WiFi is applicable for tourism crowd counting and its counting accuracy may be increased with an additional number of the virtual WiFi Access Points contributed by 5‐GHz resonance of said tags attached with touristic metallic objects. To study the 5‐GHz resonance of these tags the tag antenna is a square patch with a rectangular slot built with 3D acrylonitrile butadiene styrene printing material. The working frequency of the antenna is around 920 MHz, which can achieve a gain of 5.4 dBi and there is also a resonance at 5.6 GHz with a gain of −6.7 dBi. When the capacitor is tuned, the 5‐GHz band of WiFi is varied from 5.2 to 5.6 GHz applicable to emerging WiFi 5 and 6 CTC applications. It is anticipated that the prototype tag provides a flexible tourism crowd counting solution using CTC in the future.

3D Non-Newtonian deposition flow and thermal simulations to evaluate the scale-up potential for material extrusion of single walled ABS parts with overhang

Material extrusion (MEX) is one of the most widely used additive manufacturing (AM) techniques for polymeric materials. In the present work, 3D simulations using Ansys Polyflow are employed to address two MEX challenges: (i) avoiding sub-optimal thermal control in the deposited part, with a too low temperature leading to a weak bond between individual strands and a too high temperature resulting in too much deformation, so that a dimensionally accurate part with the same mechanical properties of the bulk material can be printed; (ii) applicability for larger nozzle diameters away from the original application of a sub 1 mm size and going to 10 mm or more, implying a higher industrial relevance. Focus is on the scale-up potential for a single walled acrylonitrile butadiene styrene (ABS) part with an overhanging structure (e.g. 30 or 45°) and strand aspect ratios between 2 and 4, considering up to 4 layers in the simulations. The small scale results are experimentally validated, showcasing the relevance of accurate 3D deposition simulations at other scales with more difficult validation procedures. It is shown that upscaling of the MEX process changes the cooling mechanism from conduction to convection driven. It is further demonstrated how simulations can be used to predict the failure of a print at a given scale and how the printing speed can be adapted to avoid such failure.

Conventional and Green Rubber Plasticizers Classified through Nile Red [E(NR)] and Reichardt’s Polarity Scale [ET(30)

After a survey on polymer plasticization theories and conventional criteria to evaluate polymer–plasticizer compatibility through the solubility parameter, an attempt to create a polymer–plasticizer polarity scale through solvatochromic dyes has been made. Since Reichardt’s ET(30) dye is insoluble in rubber hydrocarbon polymers like polyisoprene, polybutadiene and styrene–butadiene copolymers and is not useful for the evaluation of the hydrocarbons and ester plasticizers, the Nile Red solvatochromic dye was instead used extensively and successfully for this class of compounds. A total of 53 different compounds were evaluated with the Nile Red dye and wherever possible also with Reichardt’s ET(33) dye. A very good correlation was then found between the Nile Red scale E(NR) and Reichardt’s ET(30) scale for this class of compounds focusing on diene rubbers and their typical hydrocarbons and new ester plasticizers. Furthermore, the E(NR) scale also shows a reasonable correlation with the total solubility parameter calculated according to the Van Krevelen method. Based on the above results, some conclusion was made about the compatibility between the diene rubbers and the conventional plasticizers, as well as a new and green plasticizer proposed for the rubber compounds.

Parameter Sensitivity Analysis of 3D-Printed W-Band Reflective Fresnel Lens Antenna based on Acrylonitrile Butadiene Styrene Plastic

To improve the design of the 3D-printed W-band reflective Fresnel lens antenna based on acrylonitrile butadiene styrene (ABS) plastic, we have examined the parameter sensitivity related to the dielectric material constant. Although we have developed a high-gain millimeter-wave reflective Fresnel lens antenna, the material constant of the ABS filament used in 3D printing needs further investigation to optimize antenna performance. First, a 150-mm-diameter W-band reflector Fresnel antenna is designed and analyzed using finite-difference time-domain (FDTD) analysis. The analyzed and measured maximum antenna gains are 33.3 and 32.4 dBi, respectively. Subsequent sensitivity analysis focused on the impact of the loss tangent, relative dielectric constant, and folding length of the lens, based on both FDTD analysis and measurements.

Novel Distance-Based Molecular Descriptors for Styrene Butadiene Rubber Structures

Styrene-butadiene rubber (SBR) is a general-purpose rubber produced from a copolymer of styrene and butadiene. It is used largely in automobile and truck tires. In general, it is considered to be an abrasion-resistant replacement for natural rubber. In this article, we compute a set of recently introduced distance-based topological descriptors namely, Zagreb connection indices and reformulated Zagreb connection indices for the SBR structures. Zagreb indices and Reformulated Zagreb indices were applied to forecast numerous molecular properties through QSAR studies of boiling point, Molar volume and bioactivity. These indices offer a quick and effective measure of molecular complexity and features of their composition resulting in approximate molecular behavior.

RMPD-22-12-09.R3 - Improvement in rheological properties of polymer-modified asphalt binder through sulfur addition using traditional and advanced analyses

The use of crosslinking agents, particularly sulfur, addresses compatibility issues in Polymer-modified binders (PmB), impacting storage stability and rheological properties. Through comprehensive rheological assessments, including Superpave grading and advanced techniques such as Glover-Rowe, master curves, Arrhenius and Power-law models, this study aimed to provide a deeper understanding of the role of sulfur as a crosslinking agent between asphalt and styrene-butadiene copolymer (SB), investigating its influence on the durability and performance of the asphalt binder. Results show sulfur levels up to 0.3%, enhanced PmB's elasticity, resistance to shear deformation, rutting, low-temperature cracking, and fatigue, making it suitable for a wider range of climatic conditions and heavier traffic levels. Beyond this threshold, the binder became very stiff and less workable, suggesting the potential onset of gelation. An optimal sulfur content in PmB enhanced compatibility, rheological properties, and overall efficiency of binder modification, potentially reducing polymer modification costs.

Mechanical and Durability Evaluation of Latex Modified Lightweight Concrete

Modified polymer concretes are popular materials in the construction industry due to their relatively high performance, versatility and stability compared to ordinary cement concrete. In this research, by adding three different latexes, including styrene butadiene rubber, ethylene vinyl acetate and acrylic latex, the mechanical and durability properties of Light weight concrete with Leca aggregates were measured. In this regard, 15 different mixtures are carried out in two laboratory programs. in the first stage, the effect of each latex with 5, 7.5 and 10% percentages with cement are investigated, and in the next stage, the simultaneous effect of latex with Microsilica. It was measured on the properties of lightweight concrete. The results showed that the addition of latex has a significant effect on increasing the durability factors of lightweight concrete several times. With the combination of 7.5% latex and 7% Microsilica, the best compressive strength has been recorded. By using latex, the flexural strength of concrete increased around 30%. Also, the passing charge of the lightweight concrete sample without latex is 4124 coulombs, while the sample containing 10% ethylene vinyl acetate passes 451 coulombs of charge.

Evaluation of a Strain Sweep Tests Protocol as a Tool for Assessing the Homogeneity of SBR Copolymer Composition

Global competition in products and services demands constant improvement in production systems. Similarly, it is essential for industries to have quality control tools capable of assessing the compliance of a given product at a lower cost and with greater effectiveness. In the rubber and composite industry, where complex formulation and mixing systems can affect not only the quality of the final product but also the processing of rubber, the development of a protocol that assumes this function is important. The present study developed samples of elastomeric blends based on styrene-butadiene copolymer (SBR) with different filler concentrations (30, 60, and 90 phr of ground tire rubber as filler), which were analyzed using an oscillating cavity rheometer (MDpt-TechPro). Based on a proprietary testing protocol, the degree of homogeneity of the composites was evaluated, which was compared with scanning electron microscopy studies. The implemented protocol, which provides results within 30 minutes, proved to be promising for quality control of these blends, and it can be used by rubber processing industries, saving both time and cost, being an unprecedented study on the 'homogeneity-rheology' relationship.

Nano Zero-Valent Iron (nZVI) Encapsulated with ABS (nZVI/(ABS + EC)) for Sustainable Denitrification Performance and Anti-Aggregation

Aggregation and sharp reactivity decrease are the key problems of using nano zero-valent iron (nZVI) as a potential reaction medium for a permeable reactive barrier (PRB). In this study, nZVI particles encapsulated within an acrylonitrile–butadiene–styrene (ABS) matrix (nZVI/(ABS + EC)) was fabricated, which for the first time successfully simultaneously solved the above problems via accurately regulating the distribution of nZVI particles in the ABS matrix and regulating the contact between nZVI particles and the contaminated aqueous environment. In addition, the size and number of the pores throughout the ABS matrix were first regulated by ethyl cellulose (EC) for the purpose of controlling the contact between nZVI particles and the nitrate contaminant, affording apparent rate constants (kobs) for denitrification performance in the range of 0.0423 to 0.0820 min−1. The remediation of simulated nitrate-contaminated solution by nZVI/(ABS + EC) was suitably described by the first-order kinetics model, with kobs ranging from 0.0423 to 0.2036 min−1, and functional relationship models of kobs with the dosages of EC (dEC) and nZVI (dFe) during encapsulation were developed for the quantitative regulation of a sustainable denitrification performance. Results revealed that encapsulation prevents the aggregation of nZVI, rendering a sustainable denitrification performance of the material; the denitrification performance was demonstrated to be affected and quantitatively regulated by the encapsulation and application conditions. Using nZVI/(ABS + EC) as the reaction medium for PRB, the pore blocking of PRB can be avoided, and the sustainable remediation performance can be quantitatively regulated and predicted.

Study on fire resistance and mechanical properties of modified recycled waste oyster powder in asphalt binder

AbstractIn this study, an eco‐friendly approach is presented for the innovative use of waste oyster shell (OS) powder modified with zinc stannate, aliphatic alcohols, and silane coupling agents blended with styrene‐butadiene‐styrene (SBS) modified asphalt to make a flame‐retardant binder (modified oyster shell [MOS]/styrene‐butadiene‐styrene [SBS]/MA), which is rendered flame retardant and smoke suppressive. Compared with the original SBS/MA, MOS/SBS/MA with a 2% addition rate showed a 35.44% increase in ultimate oxygen index, a 30.62% reduction in peak exotherm, a 10.87% reduction in smoke density, and a 75% reduction in volatile organic compound (VOC) emissions. It also has excellent mechanical properties, with increases in composite modulus, elastic modulus, and storage modulus of 68.58%, 97.29%, and 59.59%, respectively, at 46°C. The thermal stability of MOS/SBS/MA is also improved, with a decomposition temperature 26°C higher than that of SBS/MA. Pavement performance tests show that the water‐soaked Marshall's split strength has increased by 3.87% and the coefficient of rutting by 3.51%. Increased by 3.51%, this method effectively utilizes the waste OS, improves the fire‐retardant properties of asphalt while retaining the mechanical properties of the modified asphalt binder, and provides a model for developing sustainable fire‐retardant asphalt in coastal areas.