Dispersed Silica Research Articles

In Ukrainian

Curcumin, a sparingly soluble polyphenol of plant origin, has antitumor, anti-inflammatory, antithrombotic, antidiabetic and antimicrobial properties. Currently, an important task is the development of medicinal composites based on curcumin, which provide an increase in its solubility and, accordingly, bioavailability. The aim of the work is to determine the optimal conditions for the adsorption of curcumin on the surface of a silica enterosorbent as soluble supramolecular complexes with a cationic dimeric surfactant decamethoxine. The UV/Vis spectroscopy data indicate that supramolecular interactions with decamethoxine lead to changes in the spectral characteristics of curcumin in solutions and on silica surface. The bathochromic shift of the absorption spectrum of curcumin in decamethoxine solutions characterizes the polarization of its carbonyl group in supramolecular complexes. The hypsochromic shift in the absorption spectra of curcumin adsorbed from decamethoxine solutions on silica is explained by the violation of its conjugated π-bond system, resulted probably from the change in the spatial orientation of the curcumin molecule at the adsorption of its complexes on the sorbent surface. Curcumin is adsorbed on highly dispersed silica much more effectively from decamethoxine solutions than from aqueous solutions. The adsorption of curcumin is maximal (92 %) at a concentration of decamethoxine 0.002 M, and decreases sharply to 9 % in the micellar region of concentrations (≥ 0.008 M). The dependence of curcumin adsorption on decamethoxine concentration is described by a domed curve, which indicates a significant contribution of hydrophobic interactions to the formation of supramolecular complexes of curcumin with cationic surfactant and their adsorption on silica surface. The results obtained are of practical importance and can be used in the development of new, more effective medicines containing bioactive curcumin, antiseptic decamethoxine and silica enterosorbent.

Recent progress of elastomer–silica nanocomposites toward green tires: simulation and experiment

AbstractThe concern regarding increasing oil consumption that originates from the high rolling resistance of automobiles has led to the development of green tires. The key enabling technique for preparing green tires involves the utilization of elastomer–silica nanocomposites. Elastomer–silica nanocomposites usually show low rolling resistance because of the intrinsic lubrication characteristics of siloxane and the excellent elastomer‐modified silica interfacial interaction, making them ideal raw materials for a green tire. It is supposed that the comprehensive properties of rolling resistance can be further improved via continually optimizing the microstructures of elastomer–silica nanocomposites. Regulating silica dispersion, understanding the interface between elastomer and silica and building the quantitative correlation between the microstructure and the static/dynamic macro‐mechanical properties are crucial in designing high‐performance elastomer–silica nanocomposites. This review aims to summarize the recent progress of elastomer–silica nanocomposites from the point of view of silica dispersion, the elastomer–silica interface and the microstructure–mechanical connection, combining simulation and actual experimental findings. A short conclusion and an outlook on the current limitations and possible future research directions for constructing high‐performance elastomer–silica nanocomposites for low‐energy green tires are also presented. © 2022 Society of Industrial Chemistry.

Crack growth rate determination of highly dispersible silica filled NR/SBR blends along with material parameters around the crack tip

AbstractBased on the viscous energy dissipation parameter around the crack tip, several intrinsic factors tend to govern the dissipation factor which in turn leads to the characteristic crack growth mechanism of the rubber vulcanizate. Herein, the crack growth behavior of different filled natural rubber (NR), styrene butadiene rubber (SBR), and NR/SBR blends was studied. It was deciphered that the 80/20 NR‐SBR (NSS) compound exhibited the lowest crack growth (dc/dn) value at all strain percentages which was in good accordance with its highest viscous energy dissipation as observed from the DMA (strain sweep) results. Also, from the theoretical calculations, dissipated energy per unit volume for NSS was 4.73 MPa, which was the highest out of all the compounds. This led to a decrement in crack growth. The lowest intensity peak in tan δ versus temperature curve, 6.5% decrement in ΔE'(storage modulus), and almost 44% decrement in ΔG’ (Payne Effect) indicates higher polymer‐filler interaction and lower filler‐filler disintegration respectively, as compared to 100 NR (NRS). The results from optical microscopy and scanning electron microscope suggested that NSS exudes the smallest crack deviation and extent of crack growth with lesser filler agglomerates making NSS the best fatigue‐resistant compound.

Synergistic impact of ionic liquid on interfacial interaction and viscoelastic behaviors of silica filled nitrile butadiene rubber nanocomposites

Ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate is used to explore the interactions between silica and rubber and replacement of silane for preparing volatile organic compounds-free vulcanizate nanocomposites. Herein we investigate the synergistic impact of IL on microscopic structure, nonlinear rheology and Mullins effect of silica filled nitrile butadiene rubber (NBR) nanocomposites. The results show that IL reacts with NBR chains and silica during compounding and vulcanization, which improves silica dispersion, bound rubber content and NBR crosslinking density and thus mediates the reinforcement and strain softening behaviors. In comparison with 5 phr usually used coupling agent bis(3-triethoxysilylpropyl)tetrasulfide, IL at the same amount could significantly improve tensile strength without influencing the dissipation energy of vulcanizates experiencing cyclic tensile deformation, which is enlightening for designing and producing vulcanizate nanocomposites with tailorable elasticity and dissipation behaviors.

Controlling the nanoparticle size of silica in an acidic environment by using a strong magnetic field and a modified sol-gel techniques

In this study, we were able to create highly dispersed silica nanoparticles with diameters of less than one nm by changing the sol-gel technique. During the poly-condensation process, a strong magnetic field was applied to the silica sol to control particle size. The size of silica nanoparticles has a substantial impact on preparation elements such pH, magnetic field intensity, and exposure time. These parameters can be changed in a systematic manner to reduce or increase particle size. A dynamic light scattering test was also used to investigate the effect of a magnetic field on the particle size and dispersion of silica dust. Despite the fact that silica is naturally diamagnetic, the magnetic field has a considerable impact on their size growth. Magnetic fields altered the typical influence on silicon structure, resulting in crystal formation in the silicon sample under consideration. Many applications require small particle sizes and/or a narrow particle size dispersion. The building blocks of nanotechnology are usually made of low-dimension particles. The experts concluded that additional research into such strange phenomena will be required in the future.

EFFECTS OF EVEN FUNCTIONAL GROUP DISTRIBUTION IN EMULSION STYRENE–BUTADIENE RUBBER PREPARED BY REVERSIBLE ADDITION–FRAGMENTATION CHAIN TRANSFER POLYMERIZATION ON THE PROPERTIES OF SILICA-FILLED COMPOUNDS

ABSTRACT Recently, considerable attention has been paid to the development of new functionalized polymers to improve the fuel efficiency of vehicles by reducing the rolling resistance of tires to adhere to strict CO2 emission regulations. Accordingly, multifunctionalized (MF) reversible addition–fragmentation chain transfer (RAFT) emulsion styrene–butadiene rubbers (ESBR) were synthesized, in which chain-end and in-chain functionalization were performed simultaneously by introducing a third monomer (glycidyl methacrylate; GMA) using RAFT polymerization. Compared with GMA ESBR, in which GMA is introduced as a third monomer by conventional radical polymerization (CRP), there was an even distribution of GMA per chain in the MF-RAFT ESBR. After preparing the silica-filled compounds, vulcanizate structure analysis and mechanical property evaluation of the compounds were performed. The MF-RAFT ESBR prepared by RAFT polymerization exhibited superior in-chain functionalization efficiency compared with GMA ESBR prepared by CRP because of the even distribution of GMA and higher crosslink density. Consequently, MF-RAFT ESBR compound showed superior silica dispersion, abrasion resistance, and lower rolling resistance compared with the GMA ESBR compound.

ПРИМЕНЕНИЕ ПОЛИСОРБА ПРИ НОВОЙ КОРОНАВИРУСНОЙ ИНФЕКЦИИ (SARS-CoV-2) И ОСТРОЙ РЕСПИРАТОРНОЙ ВИРУСНОЙ ИНФЕКЦИИ (ОРВИ) У ДЕТЕЙ

The continuation of the pandemic due to the mutations in the SARS-CoV-2 virus and the increase in the incidence of the new coronavirus infection (COVID-19) in children coupled with the intensification of severity make it necessary to continue studying of this infection. The purpose of this study was to determine the degree of influence of a modern inorganic, non-selective, multifunctional enterosorbent based on highly dispersed silica with particle sizes up to 0.09 mm, with the chemical formula SiO2, “Polisorb MP,” on the dynamics of clinical and laboratory manifestations of intoxication and diarrhea syndromes in children with SARS-CoV-2 and acute respiratory viral infection (ARVI) in the acute period of the disease. Materials and methods: the retrospective cohort study included 200 children aged 1 to 14 years old who were treated from Jan. 01, 2021 till Aug. 31, 2021 at the Tomsk Oblast Regional Children's Infectious Diseases Hospital named after G.E. Sibirtsev (Tomsk, Russia), of which 100 patients were diagnosed with COVID-19 (Group 1), and another 100 with ARVI (Group 2). The COVID-19 diagnosis was confirmed by the rRT-PCR Test detection of SARS-CoV-2 virus in nasal/oropharyngeal swabs and feces. Both groups did not differ statistically significantly by the gender (p=0.063). Results: the clinical signs corresponding to those in ARVI, but differed in the frequency of occurrence, were detected in patients with COVID-19; the statistically insignificant prevalence of upper respiratory tract lesions and mild form of the disease (71% in patients with COVID-19, and 73% in patients with ARVI, p=0.753) in the absence of specific symptoms of anosmia and dysgeusia was found. The mild gastrointestinal syndrome was observed in 37% of children in the Group 1 and in 28% of the Group 2 (p=0.175). There were no statistically significant changes in laboratory parameters found. The inorganic nonselective multifunctional enterosorbent “Polisorb MP” reduced the duration of diarrhea and intoxication by 1 to 1.5 days in both groups. Conclusion: the use of the “Polisorb MP” drug reduces the duration of intoxication and the diarrhea syndromes and normalizes the general laboratory parameters. Confirmation of the clinical form of COVID-19 requires a mandatory laboratory examination to determine the etiological significance of SARS-CoV-2 in each patient.

Fabrication and characteristics of electret using fine silica powder and its application of ultrasonic sensor

Electrets were prepared by spin-coating the dispersion of fine silica powders, and their charge retention characteristics were investigated. Finer silica aggregates were formed on the PTFE surface layer by spin-coating the dispersed solution of fine silica powder than those formed by spray-coating colloidal silica. Electrets using fine silica powder also showed better charge retention characteristics than those using colloidal silica. Such an improvement in the charge retention might be due to the suppression of discharge in the excessive gap caused by coarse silica aggregates. Then, ECSs were fabricated using the prepared electrets, and their transmitting and receiving characteristics of airborne ultrasound were also investigated. The peak sensitivity of the ECS using a spin coating of fine powdered silica dispersion was slightly improved from those using spray coating of colloidal silica. On the other hand, the peak frequency and frequency band were greatly improved using spin coating of fine powdered silica dispersion. Therefore, ECS using fine silica powder is expected to be applied as a broadband airborne ultrasonic sensor.

Cardanol grafted onto liquid isoprene rubber like groud brothers hanging on the vine: A green plasticizer and compatibilizer

The silica (SiO2) dispersion and interfacial adhesions are two essential factors for preparing rubber/SiO2 composites with excellent mechanical properties. However, the dispersion of SiO2 in natural rubber is very poor. In this study, cardanol grafted liquid isoprene rubber (CA-g-LIR) with groud-like structure was applied to adjust the interfacial adhesion between SiO2 and natural rubber (NR). The properties of the obtained rubber composites were also investigated. The results of scanning electron microscope (SEM), Mooney Viscometer (MV) and rubber process analyzer (RPA) demonstrated that CA-g-LIR improved the dispersion of SiO2 in NR, reduced the Mooney viscosity of NR, prolonged the scorching time of NR and decreased the Payne effect of SiO2 in NR. Furthermore, the tensile strength of NR100/CA-g-LIR15/SiO2 composites are higher 26.67%, 13.25% and 18.42% than NR100/LIR15/SiO2 composites when the added SiO2 is 30, 40, 50 phr respectively. In short, CA-g-LIR was found to be a plasticizer and compatibilizer as well as an anti-coke agent. The potential application of CA-g-LIR could provide a simple and convenient green strategy for industry to solve the problem of poor dispersion of polar SiO2 in non-polar rubber.

Performance Enhancement of Polymerized, Functionalized Solution Styrene–Butadiene Rubber Composites Using Oligomeric Resin towards Extremely Safe and Energy-Saving Tires

Polymerized, functionalized solution styrene–butadiene rubber (F-SSBR) is a new type of polymerized styrene–butadiene rubber solution containing specific terminal groups, which can be used in treads for high performances. However, the wet skid resistance related to safety, the rolling resistance to energy consumption, and the wear resistance to service life are often contradictory and form the performance “magic triangle”. In this work, oligomeric resins, including Coumarone resin, C9 resin, C5/C9 resin and a styrene-α-methyl styrene copolymer (SSC), were used as tire functional additives and selected to replace treated distillate aromatic extract (TDAE) to improve the performances of silica-filled F-SSBR composites. The C9 resin, C5/C9 resin and SSC could enhance the modulus at 300% and tensile strength of the F-SSBR composite. The four resins could improve the wet skid resistance and wear resistance of the composites. However, Coumarone resin caused poor silica dispersion in the F-SSBR matrix and eventually, the lower modulus, higher loss factor at 60 °C and the higher heat buildup in the composite were comparative to the composite with TDAE. Furthermore, the synergistic effect of the C5/C9 resin and SSC was found to improve the mechanical performance of the composites and it resulted in higher tensile strength and modulus, and a lower heat buildup, compared to the case when only TDAE was used. It is noted that the properties “magic triangle” was broken by the C5/C9 resin and SSC, and the C5/C910T15 increased the wet skid resistance by 21.7%, fuel-saving rate by 2.3%, and wear resistance by 8.3%, while S20T5 increased the wet skid resistance by 30.4%, fuel-saving rate by 7%, and wear resistance by 25% compared with CG.

3‐Octanoylthio‐1‐propyltriethoxysilane functionalized silica/rubber composites for application in tire: Structure, performance and synergism

AbstractIncreasing the polymer‐filler interaction is a challenge to develop high performance rubber composites. In this study, a new blocked mercaptosilane (3‐Octanoylthio‐1‐propyltriethoxysilane) was used to increase the rubber‐silica interaction by modifying highly dispersible silica and fumed silica surface with this silane. A two‐step process was used for the modification. Successful hydrolysis and condensation reaction was proved by Fourier‐transform infrared spectroscopy. Grafting density and grafting percentage were determined using thermogravimetric analysis. The modified silica/rubber composites were compared with the compositions where silane was separately added during mixing. Dynamic modulus versus strain signatures demonstrated strong polymer‐filler interaction after functionalization of the silica surface. The composites containing modified silica demonstrated improved mechanical properties and abrasion resistance over the unmodified one, which were correlated with the dispersion index. Dynamic mechanical analysis showed 28% improvement of rolling resistance and 67% improvement of ice traction after modification. Amount of silane modified silica also varied in total filler loading for precipitated silica/rubber composites. Silica‐rubber composites, where hybrid silica structure (75/25 modified and pristine silica ratio) was used, displayed interesting property to fulfill the requirement of green tire composites. Such a finding can be extended to developing tires for energy efficient vehicles.

Use of naturally small molecule as an intelligent interfacial modifier for strengthening and toughening silica-filled rubber composite

The incorporation of interfacial modifiers into silica-filled rubber composite is necessary to optimize the composite properties because abundant silanol groups on silica surface make it essentially incompatible with non-polar rubbers. The modification of silica-filled composites with the commonly used silanes generally causes many constraints such as excessive silane dosage, high temperature compounding, volatile organic compound emission, and loss of toughness of the composite. In this contribution, we reported the use of naturally small molecule thioctic acid (TA) as an intelligent interfacial modifier for silica-filled styrene-butadiene rubber (SBR) composite. The carboxyl group of TA can interact with silica through hydrogen bonds, meanwhile the disulfide bond of TA can be cleaved to generate sulfur radicals and then couple with SBR macroradicals during compounding and curing, making TA a bridge between silica and SBR matrix. In the TA-modified composite, silica dispersion is greatly improved and hydrogen bond-mediated interface is constructed. When comparing with the most widely used bis-(γ-triethoxysilylpropyl)-tetrasulfide, TA-modified composites exhibit simultaneously improved strength, modulus, toughness and tear strength, which is on account of the reversible energy-dissipating mechanism of the hydrogen bond-mediated interfaces.

Exploring the Effect of Dispersed Phase on the High Strain Rate Mechanical Response of Nanosilica Dispersions

Shear Thickening Fluids (STFs) constitute a special class of materials which exhibit phase transition from low to high viscosity state when exposed to shearing forces, particularly, when the applied shear rate exceeds a critical value. The last decade has witnessed a mutual symbiotic relationship between STF and high-performance fabrics such as Kevlar®, Dyneema®, Ultra High Molecular Weight Polyethylene (UHMWPE) etc., to produce new light weight and flexible protective materials systems with enhanced knife, stab and ballistic resistant properties than the existing ones. In this study, we explore the effect of particle shape and size on the high strain rate dynamic response of nanosilica dispersions. Shear thickening fluid (STF) was synthesized using fumed silica and spherical nanosilica particles, comprising the dispersed phase, whereas PPG400 (Polypropylene Glycol) was used as the dispersion medium. Ultrasonic homogenization technique was used for the synthesis of STF. The low strain rate rheological characterization was conducted on MCR302 rheometer at 25°C, whereas the high strain rate characterization was performed on inhouse designed and developed SHPB (Split Hopkinson Pressure Bar) apparatus. Fumed silica (FS) particles possess high specific surface area owing to their fractal structure. Therefore, their low molecular weight dispersions exhibit shear thickening behavior thus making them potential candidates for liquid body armour applications. On the other hand, spherical silica dispersions exhibit shear thickening behavior in high phase volume concentrations. Experimental studies showed that spherical silica based STF dispersions exhibited enhanced shear thickening in the low strain rate domain, as well as better mechanical response in terms of higher peak stress under high strain rate compressive loading conditions, during SHPB testing, in comparison to their fumed silica counterpart. Thus, it can be inferred that the mechanical response of nano-silica dispersions is influenced by the shape of the particles constituting the dispersed phase.

The Effect of Different Dosages of TESPT on Metal Friction and Metal Wear in the Mixing Process.

Studies show that the dispersion of silica in the mixing process is an important factor affecting the wear of the mixing chamber. As the most important mixing equipment, the long operational life of the internal mixer will cause wear in the rotor and chamber of the internal mixer. This wear increases the gap between the rotor and chamber of the internal mixer, reduces the mixing performance, weakens the dispersion of packing, and adversely affects the quality of the rubber produced. Therefore, it is important to investigate the metal wear in the mixing process. This article examines the effect of the addition of different amounts of silane coupling agents on metal friction and wear during the mixing process. The silane coupling agent has two functions. The first is to make the surface of the silica hydrophobic, enabling it to combine the inorganic matrix of the silica with the organic matrix of the rubber; the second is to inhibit the aggregation of the silica in the rubber. In the present study, we examine (1) the influence of different formulations on the friction and wear of the metal in the mixing chamber from the perspective of formulation technology, and (2) the correlation between corrosion wear and abrasive wear. It is found that a rubber compound with 6 phr of TESPT has the lowest metal wear and that adding more TESPT does not affect the degree of metal wear. As the amount of TESPT increases, the proportion of abrasive wear decreases, while the proportion of corrosive wear increases, reaching a maximum of 20.7%. In our study we found that abrasive wear is the predominant wear mechanism of a rubber compound on metal. In contrast, the corrosive wear caused by high-temperature water vapor still occupies a large proportion of the total wear. Therefore, improving silica dispersion and reducing abrasive wear are extremely important methods to protect the mixing chamber. However, the corrosion of metals by high-temperature water vapor should also be considered when preparing for the mixing process.

Experimental and Computational Studies on Octyl Hydroxamic Acid as an Environmentally Friendly Inhibitor of Cobalt Chemical Mechanical Polishing.

Octyl hydroxamic acid (OHA) was investigated as an inhibitor in H2O2-based alkaline silica dispersions for the polishing of cobalt (Co) films for interconnect applications. A combination of experiments and density functional theory (DFT) was used to investigate the inhibition effect and the mechanism of OHA on the Co surface. On the basis of the experiments, it can be proven that OHA has an inhibition effect on Co, which came from the inhibition of the cathodic reaction. The X-ray photoelectron spectroscopy (XPS) experiments show that the adsorption of OHA weakened the oxidation of the Co surface and protected the Co surface from corrosion. On the basis of the calculations, it can be proven that the OHAketone (ion) is most likely to react with the Co surface, and it can adsorb on the Co surface by Co-O bonds. This study provides important microscopic insights for understanding the corrosion protection of Co interconnect metals and helps to explain the corrosion inhibition mechanism of the organic-metal interface during the CMP process.

Performance enhancement of bio‐based rubber composites using epoxidized natural rubber for silica without carbon emissions and volatile organic compounds

AbstractTire development tendency is green, environment‐friendly, and safeguarding life and health. The conventional tires, consisting of solution polymerized styrene‐butadiene rubbers (SSBR), silica, silane coupling agents, and other rubber additives, will not be able to keep up with the demand. SSBR, as a synthetic rubber processed from nonrenewable petroleum resources, creates a large amount of carbon emissions in the production process and the reaction between silica and silane coupling agents generates a large amount of volatile organic compounds (VOCs), which is detrimental to the environment and human health. In this article, epoxidized natural rubber (ENR) with different epoxide degrees was successfully prepared and blended with natural rubber (NR)/silica composites to improve the dispersion of silica and the performance of nanocomposites. The effect of heat treatment temperature on the reaction between ENR and silica and the dynamic and static mechanical properties of ENR/NR/silica nanocomposites was investigated by mechanical properties test, transmission electron microscopy, x‐ray photoelectron spectroscopy, and Fourier transform infrared. The results showed that the epoxy groups on the ENR molecular chain could react with the silanol on the surface of silica to form a strong chemical bond, which improved the dispersion of silica in the rubber matrix and further enhanced the performance of the rubber composites without carbon emission and VOCs.

Optimization of highly dispersible silica/carbon black hybrid filler ratio for tire tread based on solution‐ andemulsion‐styrenebutadiene rubber

AbstractIn this study, the effects of hybrid filler ratio and styrene‐butadiene rubber (SBR) type on tire tread performance that is, wet grip (WG), fuel‐saving efficiency (FSE), and abrasion resistance, were focused. Two types of SBR that is solution‐SBR (S‐SBR) and emulsion‐SBR (E‐SBR) were selected and reinforced by various ratios of highly dispersible silica (HDSi) to carbon black (CB). Although increasing the CB ratio had negative effects on WG, FSE, heat build‐up, and dynamic set, it improved abrasion resistance. Results revealed a good balance of tire performance at a CB ratio of 40 wt%. Clearly, S‐SBR provided better overall tire performance than E‐SBR, particularly in the silica‐filled system. This is possibly due to the higher glass transition temperature (Tg) and the greater magnitudes of rubber‐filler interaction and crosslink density of S‐SBR. Surprisingly, the HDSi/CB hybrid ratio and the SBR type had little influence on the degree of filler dispersion, probably because of the sufficiently long mixing time employed in this experiment.

Jojoba seed powder as eco‐friendly antioxidant for rubber products

AbstractIn search of a new class of antioxidants for rubber products, plant based antioxidants have emerged as a suitable alternative to traditional antioxidants. Therefore, this study aimed to explore the efficiency of jojoba seed meal (JSM) as a natural antioxidant in rubber compounds. Hence, JSM was ground and sieved into a very fine powder (JSMP) where it was applied here in silica‐filled acrylonitrile butadiene rubber (NBR) composite at different loadings. Its effect on the curing, swelling, physico‐mechanical, aging and dielectric properties of the resulting composites was investigated. It was found that the incorporation of JSMP into silica‐NBR composites enhanced the curing, mechanical, and swelling properties compared to those of the composite prepared with the commercial antioxidant 2,2,4‐trimethyl‐1,2‐dihydroquinoline (TMQ) and the optimum concentration of JSMP was 4 phr. This result was proved by SEM which showed that using up to 4 phr of JSMP enhanced the dispersion of silica within the NBR matrix. Aging process results showed that the composites with JSMP exhibited a high resistance to the aging process compared to that with TMQ. Furthermore, the dielectric results revealed that the presence of JSMP caused an increase in the permittivity, dielectric loss, and conductivity of the resulting composites. The conductivity value reached to 8 × 10−7 S/cm which recommends the use of such composites for electrostatic dissipation applications.

Poly‐cardanol as plasticizer and compatibilizer on styrene butadiene rubber with improved processability and silica dispersion

AbstractNatural products used as plasticizer can inhibit its migration in rubber and improve the dispersion of inorganic power. Herein, styrene butadiene rubber (SBR) was plasticized by poly‐cardanol (PCA) originated from the Friedel–Crafts alkylation without solvent of cardanol which was extracted from abandoned cashew nut shell. Results show that the Mooney viscosity of SBR/PCA compounds decreases from 45.8 to 34.7 and Tg from −52°C to −56.3°C when PCA is added from 0 to 30 phr. Moreover, the elongation at break of SBR contained 30 phr PCA increases by 515% compared with SBR. PCA also shows amphiphilic, which is verified by the improved dispersion of SiO2 in SBR/PCA compounds. The swelling ratio of SBR/PCA/SiO2 vulcanized rubber decreases and the crosslinking density increases. Meanwhile, the elongation at break of SBR70‐40 vulcanized rubber is 17.3%, which is higher than that of SBR100‐40 vulcanized rubber. PCA, acted as plasticizer and compatibilizer, provides a simple and green way for the application of natural products in the rubber industry.

Dual-Silane Premodified Silica Nanoparticles-Synthesis and Interplay between Chemical, Mechanical, and Curing Properties of Silica-Rubber Nanocomposites: Application to Tire Tread Compounds.

In silica–rubber based nanocomposites, a single organo-silicon is often used to compatibilize and covalently link silica to rubber. In this work, we have investigated the impact, at micro- and macroscales, of the decoupling of the hydrophobization and the coupling activity of silane by pretreating silica with two different silane chemistries. The first one, a mercaptosilane, is the coupling agent that promotes a covalent link between silica and rubber during the sulfur-mediated vulcanization reaction. The second one, an alkylsilane, aims to improve the silica dispersion. For both kind of silanes, we have varied the chain length and studied at macroscale the dynamic mechanical properties through the key indicators that are E′′ as loss modulus, E′ as storage modulus, and their respective ratio tan δ. The shorter silanes combination yielded an improvement in terms of wet grip indicators with tan δ at 0 °C increasing from 0.205 to 0.237 while maintaining rolling resistance indicators at the same level. We have evaluated the impact of the silane chemistry onto the cross-linking reactivity within the fabricated rubber-based nanocomposites by using moving-dye rheometer measurements (MDR). By purposely using atomic force microscopy (AFM), we have studied the silica dispersion in the matrix and the rubber/silica interface and provided the rationale explanation of the mechanical properties observed at the macroscale. AFM observation pointed out the existence of a soft interface around silica fillers when long alkylsilanes were used. We infer that this interface impacts the polymer–filler dynamic and subsequently affects the mechanical properties of the composite material.