Polybutadiene Research Articles

“Re-Think” Sulfur Curing

Since Charles Goodyear discovered the method of sulfur curing Natural Rubber in 1839, many studies have been carried out to understand its mechanism. Currently, the broadly accepted mechanism includes an activated accelerator complex formed by Zinc oxide, stearic acid, accelerators and sulfur. Furthermore, it is also broadly accepted that the coupling of the sulfur to the polymer takes place in the allylic position to the double bond. Modern passenger car tire treads no longer contain Natural Rubber but instead a blend of Solution Styrene Butadiene Rubber and Butadiene Rubber, filled with a silica/silane system. Is it possible to transfer all the gained knowledge from the Natural Rubber crosslink reaction to such modern passenger car tire tread formulations, or is it required to “re-think” sulfur curing?

Diffusion Mechanism of Waste Crumb Rubber Composite Modified Asphalt Based on Molecular Dynamics Simulation

Waste crumb rubber composite modified asphalt (CRCMA), composed of base asphalt, waste rubber powder, and several additives (softener, activator, and cross-linking agent), has been shown to effectively improve asphalt properties. The interactions between the components in CRCMA are complex, involving molecular diffusion that significantly impacts its performance. The diffusion behavior in asphalt molecules will affect various properties of asphalt and the reasons for the different properties of asphalt can be explained by studying its diffusion mechanism. Therefore, understanding the diffusion mechanism of CRCMA is essential. The molecular dynamics simulation was employed to analyze the factors influencing the diffusion mechanism, using the diffusion coefficient as a key indicator of molecular mobility. The findings showed that the diffusion coefficient of the asphalt system decreased over time but increased with temperature. The rubber composition type also had a significant impact on diffusion, with butadiene rubber (BR) showing the highest coefficient, followed by natural rubber (NR), crumb rubber (CR), and styrene-butadiene rubber (SBR). The diffusion coefficient was the lowest and the diffusion rate was slowest after adding softeners. The diffusion coefficient increased slightly with the addition of CR, and the diffusion rate was slightly accelerated but not significantly. The diffusion coefficient increased rapidly with adding activator and the diffusion rate increased significantly. With the addition of cross-linking agent, the diffusion coefficient began to decrease and the diffusion rate became slower. The CRCMA microscopic performance tests indicated that the swelling effect of CR limits diffusion, while activators promote degradation and desulfurization of CR due to the large molecule structure getting smaller, enhancing diffusion. The S=O bond in the asphalt system was regenerated and re-crosslinked to create a mesh after adding the cross-linking agent. The small molecule structure was transformed into large one. The molecular diffusion was restricted partly and thus the diffusion rate was slowed down.

4D printable and recyclable two-way shape memory butadiene rubber as ultrasensitive, longer-lasting, and lower-cost fire warning sensors

4D printable and recyclable two-way shape memory butadiene rubber as ultrasensitive, longer-lasting, and lower-cost fire warning sensors

Nitrile glove composition and performance-Substandard properties and inaccurate packaging information.

The durability and mechanical properties of synthetic medical gloves, such as those made from nitrile, vary drastically depending on the manufacturer. This study reports the chemical composition of several brands of nitrile gloves via FTIR and solid-state NMR analysis and relates composition to glove durability (found via GAD), mechanical performance (found via Instron), and whether the gloves meet or fail ASTM International standards. Out of the four nitrile examination glove brands tested, American Nitrile Slate brand had superior durability results and was found to be made of acrylonitrile butadiene rubber, as expected. The U.S. Medical glove brand, which was also found to be pure nitrile, had the superior tensile results, consistently reaching over 800% elongation before breaking. Although Restore Touch brand exam gloves were made of nitrile, they exhibited substandard tensile strength and durability due to the thinness of the glove, which barely met the ASTM minimum thickness value. The Vglove brand glove had the overall worst mechanical properties, did not meet ASTM requirements, and had an NMR spectrum consistent with that of a polyvinyl chloride glove, rather than nitrile. Gloves that fail to meet the minimum performance requirements should not be used for medical purposes to protect the health and safety of consumers.

Investigating the Effect of Nano-Crystalline Cellulose in Nitrile Butadiene Rubber Matrix for Improved Thermo-Mechanical Properties

The escalating demand for sustainable rubber products has spurred research into alternative reinforcing fillers, driven by concerns regarding the detrimental effects of using conventional fillers like carbon black and silica. In this investigation, nano-crystalline cellulose (NCC), derived from micro crystalline cellulose (MCC), sourced from sugarcane bagasse via acid hydrolysis, serves as a bio-filler to reinforce Nitrile Butadiene Rubber (NBR) matrices. NBR-NCC nano-composites were prepared using a two-roll mill, varying NCC from 1–5 parts per hundred rubber matrices, followed by hot press curing. NCC and NBR-NCC nano-composites were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), curing characteristics, thermo-mechanical testing, thermal aging and motor oil resistance. Chemical interactions between the NCC and NBR matrix were verified with FTIR. The SEM images of the NCC showed a combination of rod-like and spherical morphologies and a homogenous dispersion of NCC in NBR-NCC nano-composites with some agglomeration, notably at higher percentages of NCC. It is shown that the cure time decreases with increasing NCC loading which mimics a shorter industrial production cycle. The results also showed an increase in tensile strength, hardness, oil resistance and a rise in degradation temperature when compared to NBR at approximately 34%, 36%, 38% and 32 °C, respectively, at 3 phr NCC loading. Furthermore, NBR-NCC nano-composites showed a lower decrease in mechanical properties after aging when compared to NBR. The findings of this research suggest that the NBR-NCC nano-composites may find applications in high oil resistance seals and rubber gloves where higher thermal stability is strictly required.

Exploring the mechanical and thermal properties of rubber-based nanocomposite: A comprehensive review

Abstract The emergence and progression of synthetic rubber have paved the way in variegated prospects across various engineering and technological fields. Nonetheless, its inherent limitations such as poor mechanical and thermal properties including wear resistance, poor tensile strength, and lower thermal conductivity, as evident in styrene butadiene rubber and silicone rubber, have constrained its utility in numerous load-bearing scenarios. This limitation has been addressed by incorporating specific nanofillers into various rubber compositions, resulting in promising outcomes up to a certain threshold. Many nanofillers were trialed, such as graphite oxide, aluminum oxide, carbon nanotubes, and boron nitride. However, an attempt should be made to explore the disparity in dimensional attributes of nanofillers and their effect on different properties of rubber, thereby delineating the scope for future research. The exploration of dimensionally distinct nanofillers, such as 1D multiwalled carbon nanotubes and 2D graphene, can overcome these limitations and augment rubber’s mechanical properties and thermal properties. The study also delineates the scope of future research, which should be focused on optimizing the nanofillers’ dispersion and interfacial bonding within the rubber matrix by trying dimensionally different nanofillers.

Effect of talc modified by poly (glycidyl methacrylate)- block -polybutadiene- block -poly (glycidyl methacrylate) on the properties of nitrile butadiene rubber

Effect of talc modified by poly (glycidyl methacrylate)- block -polybutadiene- block -poly (glycidyl methacrylate) on the properties of nitrile butadiene rubber

Sustainable rubber nanocomposites for hydrogen sealings: Impact of carbon nano-onions and bio-based plasticizer

Additives play a crucial role in modifying and enhancing the properties of rubbers, improving mechanical strength, thermal stability, and chemical resistance to make them more suitable for various applications. The rubber industry faces challenges related to high resource consumption and toxic emissions, which are further impacted by the use of performance-enhancing additives. In hydrogen storage systems, tailored additives are required for rubbers to withstand elevated temperatures and high pressures, preventing hydrogen-induced swelling, a major cause of sealing failure. Herein, a novel form of carbonaceous material, carbon nano-onions (CNOs), and the bio-based plasticizer additive epoxidized soybean oil (ESO) are utilized in conventional silica-filled nitrile butadiene rubber (NBR) nanocomposites to develop low-carbon manufacturing high pressure hydrogen resistant O-rings for sealing applications. The results reveal that the incorporation of CNOs increases the crosslinking density (vc), assisted by ESO, in silica-filled NBR nanocomposites. While the conventional adipate-based plasticizer and ESO were found to be susceptible to high pressure hydrogen exposures, ESO demonstrated sustained compressive sealing properties with increase in von-Mises stress and in elevated thermo-oxidative conditions over time. The results of the life cycle assessment (LCA) recommend ESO for low-carbon manufacturing in rubber processing over conventional plasticizer.

Transforming waste into valuable resources: Recycled nitrile-butadiene rubber scraps filled with electric arc furnace slag

This study investigates the valorization of two industrial waste streams - nitrile butadiene rubber (NBR) scraps and electric arc furnace (EAF) slag – in the development of recycled NBR compounds filled with EAF slag as filler. A new recycling method for NBR scraps is employed via calendering at room temperature without the need for curatives, chemical agents, or pre-grinding. The resulting recycled NBR is then used as a matrix for EAF slag particles to produce sustainable rubber compounds that are entirely recycled. Characterization reveals that incorporating EAF slag enhances the devulcanization process of recycled NBR during recycling. The filler grain size affects composite properties like hardness, crosslink density, and tensile modulus, with finer slag particles (<50 μm) exhibiting improved reinforcement due to increased interaction surface with the rubber matrix. Dynamic mechanical analysis indicates that recycled NBR filled with EAF slag exhibits a more significant Payne effect compared to unfilled recycled NBR, due to filler-matrix interactions. Interestingly, EAF slag facilitates the rapid fractional recovery of the low-strain storage modulus after experiencing high-amplitude strain, ascribed to the formation of a rigid rubber layer around the slag particles.Overall, the findings highlight the potential to valorize these two waste materials effectively by producing functional recycled NBR/EAF slag composites with desirable properties through a simple, industrially viable recycling method without capital-intensive equipment. This represents both environmental and economic benefits through waste valorization and industrial symbiosis.

Evaluating and optimizing NBR-modified bituminous mixes: a rheological and RSM-based study.

Bitumen shows visco-elastic behavior, exhibiting both elastic and viscous properties as predicted by dynamic response and phase angle. Modern asphalt bituminous pavements face issues such as early-stage fatigue cracks, rutting, and permanent deformations due to low-temperature cracking, high-temperature deformation, moisture susceptibility, and overloading. These pavement distresses result in the formation of potholes, alligator cracks, and various deformations, which accelerate the need for rehabilitation and maintenance. To address these concerns, this study focused on utilizing Nitrile Butadiene Rubber derived from surgical gloves as an additive in conventional asphalt pavements to assess its effect on stiffness. Nitrile Butadiene Rubber was added in intervals of 2%, 4%, 6%, and 8% to conventional bituminous pavement. The rheological properties, marshall properties, dynamic modulus, and phase angle were evaluated for varying percentages of Nitrile Butadiene Rubber at different temperature, and frequency. The dynamic response was determined using a simple performance tester at four different temperatures (4.4°C, 21.1°C, 37.8°C, and 54.4°C) and six different frequencies (0.1, 0.5, 1, 5, 10, and 25Hz). Response surface methodology was employed to establish a relationship between input and output variables and to optimize the amount of Nitrile Butadiene Rubber in the mix based on dynamic modulus and phase angle. The study concluded that adding up to 6% of Nitrile Butadiene Rubber improved Marshall stability, while higher percentages led to reduced stability. A similar trend was observed in the dynamic modulus, which peaked with the addition of 6% Nitrile Butadiene Rubber, regardless of frequency and temperature. The response surface methodology model indicated that coupling the percentage of Nitrile Butadiene Rubber with frequency increased the dynamic modulus at a constant temperature, with the highest value occurring at 4.4°C. However, the dynamic modulus decreased as the temperature rose for the same combinations of Nitrile Butadiene Rubber percentages and frequencies. Numerical optimization suggested that a maximum of 5.9% Nitrile Butadiene Rubber should be added to achieve the highest dynamic modulus and lowest phase angle.

Device Model for a Solid‐State Barocaloric Refrigerator

Solid‐state refrigeration represents a promising alternative to vapor compression cooling systems. Solid‐state devices based on magnetocaloric, electrocaloric, and elastocaloric effects have demonstrated the ability to achieve high‐efficiency, reliable, and environment‐friendly refrigeration. Cooling devices based on the barocaloric (BC) effect—entropy change due to applied hydrostatic pressure, however, has not yet been realized despite the significant promise shown in material‐level studies. As a step toward demonstrating a practical cooling system, this work presents a thermodynamic and heat transfer model for a BC refrigerator The model simulates transient thermal transport within the solid refrigerant and heat exchange with hot and cold thermal reservoirs during reversed Brayton refrigeration cycle operation. The model is used to evaluate the specific cooling power (SCP) and coefficient of performance (COP) of the device comprising nitrile butadiene rubber (NBR) as a representative BC refrigerant. Experimentally validated BC properties of NBR are used to quantify the contribution of different operating parameters including cycle frequency, applied pressure, operating temperatures, and heat transfer coefficient. The results show that a BC refrigerator operating with a temperature span of 2.4 K and 0.1 GPa applied pressure can achieve an SCP of 0.024 W g−1 at 10 mHz cycle frequency and a COP as high as 5.5 at 1 mHz cycle frequency—exceeding that of conventional vapor compression refrigerators. In addition, to identify key refrigerant properties, the effect of bulk modulus, thermal expansion coefficient, heat capacity, and thermal conductivity on device performance are quantified. The results highlight the trade‐off between different material properties to maximize the BC response, while minimizing mechanical work and improving thermal transport. This work demonstrates the promise of solid‐state cooling devices based on soft BC materials and provides a framework to quantify its performance at the device‐level.

Study of Styrene Butadiene Rubber Reinforced by Polybutadiene Liquid Rubber-Modified Silica.

The dispersion of silica in rubber systems and its interaction with rubber are two key factors in the preparation of rubber composites with excellent properties. In view of this, silica modified with terminal isocyanate-based polybutadiene liquid rubber (ITPB) is used to improve the dispersion effect of silica in rubber and enhance its interaction with the rubber matrix to improve the rubber's performance. The impact of different modification conditions on the dispersion of silica and the properties of modified silica-filled rubber composites were studied by changing the amount of ITPB and the modification method of silica, including blending and chemical grafting. The experimental results show that ITPB is successfully grafted onto silica, and the use of modified silica improves the cross-linking density of rubber, promotes the rate of rubber vulcanization, and overcomes the shortcomings of the delayed vulcanization of silica itself. When the ratio of ITPB liquid rubber to silica equals 1:20, the comprehensive performance of rubber is the best, the ITPB-modified silica has a better dispersion effect in rubber, and the rolling resistance is slightly improved, with tensile strength reaching 12.6 MPa. The material demonstrates excellent overall performance and holds promise for applications in the rail, automotive, and electrical fields.

DYNAMICS IN ELASTOMERS WITH HYDROGEN BOND INTERACTIONS

ABSTRACT The dynamics of low molecular weight polybutadiene (PB) functionalized with side chains able to form hydrogen-bonded networks is investigated by a combination of calorimetry, rheology, and broadband dielectric spectroscopy (BDS). The modified PBs are found to have extremely different macroscopic viscosities with respect to the starting polymer; however, rather unexpectedly, when investigated using these three techniques, we find that the changes to the segmental motion responsible for the glass transition temperature remain unchanged. This is attributed to the high flexibility of the side chain, which does not restrict the motions of the highly flexible segments in the PB chain. In the presence of the hydrogen-bonded network we observe in both the rheological and dielectric spectra an additional relaxation, orders of magnitude slower than the segmental relaxation. We find that the temperature dependence and its dynamics are well explained in terms of the lifetime of the hydrogen bond, with a binding energy of about 100 kJ/mol.

Application of DPG/KH550 modified pyrolysis carbon black in oil and high temperature‐resistant NBR composites

AbstractIn this paper, pyrolysis carbon black (CBp) was introduced into nitrile butadiene rubber (NBR), the effects of the ratio of CBp and carbon black (N326) on the properties of NBR composites were investigated, and the optimal ratio was determined. On this basis, the accelerator DPG, coupling agent KH550 and CBp were modified by ball milling and plasma. The results showed that when the ratio of CBp to N326 was 40:15, the overall properties of NBR composites was better. Compared with the unmodified CBp/NBR composites, the change rate of tensile product, resilience and DIN abrasion of ball milling‐plasma modified CBp/NBR composites in oil environment were reduced by 52.96%, 12.81%, and 27.19%, respectively, and the tear strength after double damage by high temperature and oil bath was increased by 15.63%, which resulted in better oil and high temperature‐resistance. In summary, the ball milling‐plasma combined with DPG/KH550 modified CBp can not only replace N326 carbon black, but also realize the preparation of NBR composites with better oil and high temperature‐resistance.

Liquid carboxylated nitrile butadiene rubber via metathetic degradation with acrylic acid as chain transfer agent

Liquid carboxylated nitrile butadiene rubber (LXNBR) shows promising application in various fields. Facing the challenges in its preparation via radical emulsion copolymerization, such as gelation, molecular weight and carboxyl group content, novel approach has been developed for the controlled preparation of LXNBR via the metathetic degradation of nitrile butadiene rubber (NBR) with acrylic acid (AA) as chain transfer agent (CTA). Based on the molecular weight and carboxyl group content of the resultant products, the reaction pathway was proposed. Such understanding is expected to prepare LXNBR with designed Mn and carboxyl group content for various applications, by facile adjusting the reaction condition, mainly the feeding mode of AA, NBR concentration and reaction time.

Effect of Butadiene Rubber Crystallization on Low-Temperature Properties of Butadiene/Silicone Rubber Blends with Potential for Mars Applications

This study explores the impact of butadiene rubber (BR) crystallization on the low-temperature properties of butadiene/silicone (VMQ) rubber blends (BR/VMQ) designed for Martian applications. Two types of BR, semi-crystalline high-cis Buna CB24 and amorphous Buna CB550, were blended with VMQ, and their mechanical and thermal properties were evaluated. Kinetics of vulcanization, static mechanical properties, dynamical mechanical analysis, thermal shrinkage, and differential scanning calorimetry were utilized. The research demonstrates that the semi-crystalline BR improves mechanical properties but induces greater shrinkage at low temperatures. Conversely, using amorphous BR provided more consistent mechanical properties across the Martian temperature range and reduced material shrink by 6.71% for samples with carbon black, by 8.36% for samples with silica, and by 11.63% for unfilled samples. Future research will be required to evaluate the impact of volume change on the sealing properties of the BR/VMQ blends.

Raw rubber network of acid-free natural rubber and its application with solution-polymerized styrene butadiene rubber in green tires

Natural raw rubber was prepared by flash evaporation process (VNR), its raw rubber network was compared with that of acid-coagulated rubber (STR20), and the effects of the ratios of VNR and STR20 to SSBR on the comprehensive performance of green tire composites were investigated. The results showed that compared with 80SSBR composites, the tensile strength and tensile product coefficient of 80VNR composites were improved by 23 % and 94 %, and the Payne effect, compression heat generation, and rolling resistance were reduced by 39 %, 9 %, and 5 %, respectively. Compared with 40STR20/40SSBR composites, the tensile product coefficient, wear resistance, and wet skid resistance of 40VNR/40SSBR composites are increased by 11 %, 5 %, and 5 %, respectively, and the Payne effect, compression heat generation, and rolling resistance were reduced by 46 %, 11 %, and 5 %, respectively. This study increased the amount of natural rubber in the green tire formulations, improving the performance of composites while achieving sustainability.

Tire and road wear particles in infiltration pond sediments: Occurrence, spatial distribution, size fractionation and correlation with metals

Stormwater systems, such as infiltration ponds or basins, play a critical role in managing runoff water and reducing particulate pollution loads in downstream environments through decantation. Road runoff carries several pollutants, including trace metals and tire and road wear particles (TRWP). To improve our understanding of infiltration ponds as regards TRWP and their capacity to reduce TRWP loads, we have studied the occurrence, spatial distribution and size distribution of TRWP, as well as their relationship with metals, in considering the input of metals as tire additives, in the sediments of an infiltration pond located along the Nantes urban ring road (Western France), which happens to be a high-traffic roadway site. The sediment was analyzed using pyrolysis coupled with gas chromatography–mass spectrometry to determine the polymeric content of tires, specifically in quantifying the styrene-butadiene rubber (SBR) and butadiene rubber (BR) pyrolytic markers. By applying an SBR + BR-to-TRWP conversion factor, the results showed significant TRWP contamination, up to 65 mg/g, with a spatial enrichment from the entrance to the overflow section of the pond. Size fractionation revealed a bimodal distribution, indicating two distinct types of TRWP. The first type is characterized by small diameters (63–160 μm), suggesting the presence of TRWP less integrated with mineral and organic particles. The second type, characterized by larger diameters (200–500 μm), suggests a more pronounced integration with these same mineral and organic particles. A significant positive correlation between TRWP and metals (As, Cd, Cr, Cu, Li, Mo, Ni, Sb, V, Zn) was found (r > 0.739, p < 0.05). This correlation implies that TRWP and/or their associated phases may act as an indicator of metal contamination in the pond sediments. Lastly, a mass balance between TRWP inputs and the amount retained in the sediments underscores the role of infiltration ponds as “sinks” for TRWP.

Stimulating the Electrostatic Interactions in Composite Cathodes Using a Slurry-Fabricable Polar Binder for Practical All-Solid-State Batteries

In this work, poly vinylidene fluoride–chlorotrifluoroethylene (PVdF-CTFE) is introduced as a slurry-fabricable polymer binder to fabricate a stable composite cathode using the complex materials of a Li[Ni0.7Co0.1Mn0.2]O2 cathode, Li6PS5Cl electrolyte, and super C carbon, for sulfide-based all-solid-state batteries (ASSBs). The high electronegativity of fluorine in the poly(vinylidene fluoride–chlorotrifluoroethylene (PVdF-CTFE) binder creates a polarized electronic environment in the composite cathode, promoting electrostatic interactions with Li ions. Compared with that of butadiene rubber (BR), the PVdF-CTFE binder has a stronger binding energy to the complex materials in the composite cathode, which enhances the mechanical rigidity of the composite cathode with highly uniform adhesion. In addition, uniform and close contact between the complex materials in the composite cathode reduces the resistance at the interfaces, lowering the energy barrier for Li+ diffusion, and eventually creates a fast Li+ diffusion pathway in the composite cathode. Thus, the pouch-type ASSBs cell, which comprises the composite cathode with the PVdF-CTFE binder, Li6PS5Cl electrolyte sheet, and silver-carbon (Ag/C) Li-free anode delivers a high reversible capacity of 198.5 mAh g–1 at 0.1 C and long-term cycling stability over 300 cycles with a capacity retention of 74.5 % at 0.5 C at 60 °C.

Robust and Flexible Rubber Composite with High Photothermal Properties Achieved by In Situ ZDMA Assisted Dispersion of Eumelanin and its Hydrophobic Photothermal Application.

Eumelanin, a natural, biocompatible, and biodegradable photothermal agent derived from biomass, has attracted increasingly considerable attention due to its outstanding photothermal conversion efficiency. Unfortunately, its tendency to aggregate in flexible non-polar polymers, owing to its abundant polar groups on the surface, severely restricted the application of eumelanin in photothermal composite field. Herein, a feasible strategy is proposed to disperse eumelanin in non-polar rubber matrix via in situ generation of Zinc dimethacrylate (ZDMA). The graft-polymerization of ZDMA promotes the interfacial compatibility between styrene butadiene rubber (SBR) and eumelanin, achieving a uniform dispersion of eumelanin in SBR. The rubber composite exhibits a considerable tensile strength of 11.4MPa, acceptable elongation at break of 146%, and outstanding photothermal conversion efficiency of up to 75.2% with only 1wt% of eumelanin. Furthermore, based on the easy-processing of SBR matrix, the composite is treated with a sandpaper template technique and sprayed with trimethoxy(1H,1H,2H,2H-perfluorodecyl)silane (PFDTMS) to endow the material with near superhydrophobicity (water contact angle of 147.9°) capacity. Hydrophobicity provides excellent icing resistance, with droplet surfaces extending more than twice as long to freeze. Moreover, this hydrophobic photothermal material exhibits remarkable anti-frosting, de-frosting, and de-icing capabilities.