Rubber Filler Research Articles

Deformation Characteristics of Rubber Waste Powder–Clay Mixtures

With the increasing accumulation of rubber waste, the potential reuse of rubber fillers offers a promising solution to enhance the engineering properties of low-plasticity soils while promoting environmental sustainability. In this study, the effect of rubber waste powders (RWPs) on the consolidation and deformation properties of low-plasticity clay soil (CS) was investigated using a fully automated consolidation testing procedure for clay–rubber mixtures. The study involved adding 2% up to 30% RWPs to Tehran clay, and various parameters were evaluated through consolidation, compaction, and uniaxial strength tests. The results revealed that the consolidation volume of the mixture differed from that of the CS due to the elastic nature of the rubber wastes (RWs). To achieve higher precision, a new equation was proposed to determine the void ratio, along with modified e-log p’ curves for the clay–rubber mixture. Furthermore, the addition of RWPs to the CS resulted in moderated free swelling of the soil while enhancing ductility, compression index (Cc), swelling index (Cs), and recompression index (Cr). However, it was observed that the strength and modulus of elasticity of the mixture decreased with the increase in rubber content. Considering the variations in geotechnical parameters with different rubber contents, the appropriate rubber content can be selected based on specific applications in soil and rubber mixtures, considering the required geotechnical parameters. This study highlights the potential applications of RWPs as a material in civil and geotechnical engineering projects, providing valuable insights for sustainable and eco-friendly engineering practices.

Preparation of Calcium Carbonate from Cockle Shells as Fillers in Natural Rubber

The purpose of this research is to study the preparation of calcium carbonate from cockle shells by precipitation method and compare it to calcium carbonate from high temperature heating, commercial calcium carbonate, and cockle shell powder. The properties of the vulcanized natural rubber mixed with different types of calcium carbonate were observed. It appeared that the precipitated calcium carbonate delivered the best properties (hardness, 300% modulus, tensile strength, elongation at break, tear strength, and abrasion resistance), followed by the high temperature heated calcium carbonate, the commercial calcium carbonate, and the cockle shell powder, respectively. This result corresponded to the morphology from the scanning electron microscope (SEM); the precipitated calcium carbonate had crystalline form and the most uniform particle size, followed by the high temperature heated calcium carbonate, the commercial calcium carbonate, and the cockle shell powder. In particular, the cockle shell powder was composed of large and small particles dispersed over a wide range, which brought about the weak point of vulcanized rubber and caused the lowest properties of the vulcanized rubber mixed with cockle shell powder.

The Mechanical Properties Improvement of Polyurethane Rubbers by Using Titanium Oxide and Calcium Carbonate Modifiers (Additives)

The structure of polyurethane and the physico-chemical properties of its components are considered. The most promising modifiers have been selected: TiO2, CaCO3. The features of the preparation of the studied polyurethane mixture, its composition, manufacturing technology and equipment are described in detail. The geometric properties, manufacturing processes and testing methods of samples are presented. The graphical dependencies of the influence of the parameters of sample preparation on their mechanical properties such as hardness, tensile stress at break, Jung s modulus are given. The rational parameters of the technology for the production of samples modified with fillers to give them stable mechanical properties have been set. The maximum proportions of these fillers in polyurethane rubber are limited to 30-35%. It is proved that the addition of TiО2 and CaCО3 to the composition of polyurethane rubbers gives them special properties that allow them to expand the range of their industrial usage.

The development of composite reinforced hybrid fiber musa acuminata stem-hibiscus tiliaceust bark with filler liquid rubber as vehicle bumper

The characterized of the polyester composites reinforced of the hybrid fiber musa acuminata stem fiber (MASF)-hibiscus tiliaceust bark fiber (HTBF) with liquid rubber filler was studied. The object of research is the polyester composite material, hybrid natural fiber reinforcement and filler Carboxyl Terminated Butadiene Acrylonitryle (CTBN). The polyester composite material which is used as a vehicle bumper, is easily broken and has low heat resistance so that its shape easily changes/shrinks due to heat. This research aims to develop the tensile strength, impact toughness and heat resistance of polyester composites. The reason for using the MASF-HTBF hybrid fiber as a reinforcement for polyester composite materials is because MASF and HTBF are natural fibers that have great potential to be developed to improve the mechanical properties of polyester composites, as substitutes for synthetic fibers. In this study, the conditions of MASF and HTBF were given alkaline treatment by immersing them in 5 % NaOH solution for 24 hours then drying. The combined/hybrid ratio between the MASF and CTBF volume fractions is: 5 %:25 %, 10 %:20 % and 15 %:15 %. To increase impact toughness, CTBN filler is added with variations of 5 %, 10 %. The mechanical characteristics of the specimens were carried out by means of a tensile test and an impact test. The change in mass or shrinkage as a result is tested by TGA. The results showed that the MASF-HTBF hybrid fiber-reinforced polyester composite material with CTBN filler has better mechanical properties than single natural fibers, so it is important to develop it further as a material for making vehicle bumper

English

Starch fillers were extracted from three plant sources namely amora tuber, Tacca lentopeteloides; sweet potato, Ipomoea batatas; yam starch, Dioscorea rotundata and their particle size, pH, amylose, and amylopectin percentage decomposition determined accordingly. The starch was introduced into natural rubber in liquid phase (through gelatinization) by the latex compounding method and compounded according to standard method. The prepared starch/natural rubber composites was characterized by Instron Universal testing machine (UTM) for tensile mechanical properties. The composites was further characterized by x-ray diffraction and crosslink density analysis. The particle size determination showed that amora starch granules has the smallest particle size (156 × 47 μm) followed by yam starch (155 × 40 μm) and then sweet potato starch (153 × 46 μm) with the biggest particle size. The pH test also revealed that amora starch has a near neutral pH of 6.9, yam 6.8, and sweet potato 5.2 respectively. Amylose and amylopectin determination showed that yam starch has a higher percentage of amylose (29.68), followed by potato (22.34) and then amora starch with the lowest value (14.86) respectively. The tensile mechanical properties testing revealed that yam starch produced the best tensile mechanical properties followed by amora starch and then sweet potato starch. The structure, crystallinity/amorphous nature of the product composite was confirmed by x-ray diffraction, while the nature of crosslinking was confirmed by swelling test in toluene solvent using the Flory-Rehner approach. The increasing values of crosslink density in the starch/rubber composite is a clear evidence of good interfacial adhesion between the starch fillers and the rubber, hence good dispersion of starch fillers in the rubber. This research has rendered a workable strategy for enhancing interfacial interaction between a hydrophilic filler (Starch) and hydrophobic polymeric matrix (natural rubber) yielding moderately good tensile mechanical properties with prospects for the rubber processing industry. The studied fillers can partially replace carbon black as natural rubber fillers with reduced cost, no risk to human health and also an environment friendly approach. Key words: Natural rubber, fillers, starch, amylose, amylopectin, crosslink density, mechanical properties.

Preliminary Study on the Preparation of Conductive Nanosized Calcium Carbonate Utilizing Biogas Slurry by a Synchronous Double Decomposition Coating Method.

Nanosized calcium carbonate (NCC) plays a vital role in the rubber and plastic fields as a filler, but it cannot resolve the electrostatic problem. Humic-acid-based NCC (HA-NCC) was accidentally discovered in the reaction between biogas slurry and calcium chloride (CaCl2), based on nutrient recovery and gradient treatment technology to solve the biogas slurry problem. A preliminary study on the preparation of conductive nanosized calcium carbonate (CNCC) from the HA-NCC was implemented. Meanwhile, a synchronous double decomposition coating method was proposed to properly explain the formation of HA-NCC in the biogas slurry. The CNCC was further obtained through drying and carbonizing the HA-NCC sample. The morphology of CNCC was a square shape with aggregation, and its crystals were calcite. The C content of CNCC was 5% higher than that of the normal CaCO3, implying a synchronous coating effect of soluble HA in biogas slurry on NCC. The weight loss of CNCC was about 2.5% at 630 °C, explaining why the HA-NCC remained black at 550 °C for 4 h. The CNCC was partly ordered and graphitized. The resistivity of the CNCC reached 2.62 × 106 Ω·cm. It could be used as a conductive powder. In view of the favorable characteristics described above, CNCC would be expected to be a filler and antistatic agent for plastics and rubbers to enhance the tensile and bending resistance of polymer materials, while eliminating electrostatic hazards. The results are also of great significance for developing high-end products to realize resource utilization of biogas slurry.

Preparation of high‐performance and low‐rolling resistance tire tread compound based on hydrogen‐bonded self‐assembled graphene/carbon nanotube‐silica hybrid

AbstractGraphene/carbon nanotubes and silica hybrids (CTGS) with high dispersion and strong interface were prepared by hydrogen bond self‐assembly technique using green modifiers Tween‐80 (TW) and Oleylamine (YA) as “molecular bridge.” CTGS was added into natural rubber (NR) as an effective functional filler to prepare high‐performance, low‐rolling resistance, and antistatic tire tread. In the vulcanization process of NR filled with CTGS (CTGS/NR), CTGS can participate in the rubber vulcanization, and co‐vulcanization is a catalyst for constructing the strong interfacial interactions between CTGS and rubber. The extreme dispersion of CTGS hybrid in NR and the strong interfacial interaction between CTGS and NR are the basis for obtaining excellent comprehensive properties of CTGS/NR composites. The results show that compared with NR filled with silica modified by triethoxysilyl propyldisulfide (ST@SiO2/NR), NR filled with carbon nanotubes and silica hybrid (CTGS4) using YA as the molecular bridge (CTGS4/NR) has the best comprehensive performance. Its tensile strength increased from 27.41 to 30.18 MPa, increasing by 10.1%, the rolling resistance decreased from 0.098 to 0.087, decreasing by 11.2%, and the conductivity increased by three orders of magnitude (increasing from 2.321 × 10−7 S∙m−1 to 4.111 × 10−5 S∙m−1) indicating excellent electrostatic conductivity for CTGS hybrid with carbon nanotubes loading as low as 0.6 wt%. CTGS hybrid is expected to be a new functional filler for rubber, especially good for green tires with high‐performance, low‐rolling resistance, and antistatic performances.

Natural Rubber Composites Using Hydrothermally Carbonized Hardwood Waste Biomass as a Partial Reinforcing Filler-Part II: Mechanical, Thermal and Ageing (Chemical) Properties.

Natural rubber composites were reinforced by the co-fillers 'hydrochar' (HC), obtained by hydrothermal carbonization of hardwood sawdust and commercial carbon black (CB). The content of the combined fillers was kept constant while their ratio was varied. The aim was to test the suitability of HC as a partial filler in natural rubber. Due to its larger particle size and hence smaller specific surface area, large amounts of HC reduced the crosslinking density in the composites. On the other hand, due to its unsaturated organic character, HC was found to display interesting chemical effects: if it was used as the exclusive filler component, it displayed a very strong anti-oxidizing effect, which greatly stabilized the rubber composite against oxidative crosslinking (and hence embrittlement). HC also affected the vulcanization kinetics in different ways, depending on the HC/CB ratio. Composites with HC/CB ratios 20/30 and 10/40 displayed interesting chemical stabilization in combination with fairly good mechanical properties. The performed analyses included vulcanization kinetics, tensile properties, determination of density of permanent and reversible crosslinking in dry and swollen states, chemical stability tests including TGA, thermo-oxidative aging tests in air at 180 °C, simulated weathering in real use conditions ('Florida test'), and thermo-mechanical analyses of degraded samples. Generally, the results indicate that HC could be a promising filler material due to its specific reactivity.

Elucidation of Response and Electrochemical Mechanisms of Bio-Inspired Rubber Sensors with Supercapacitor Paradigm

The electrochemical paradigm of a supercapacitor (SC) is effective for investigating cutting-edge deformable and haptic materials made of magnetic compound fluid (MCF) rubber in order to advance the production of bio-inspired sensors as artificial haptic sensors mimicking human tissues. In the present study, we measure the cyclic voltammetry (CV) profiles and electric properties with electrochemical impedance spectroscopy (EIS) to morphologically evaluate the intrinsic structure of MCF rubber containing fillers and agents. In addition, the electrochemical mechanisms of molecule and particle behavior are theorized using the SC physical framework. The solid-doped fillers in the MCF rubber characterized the behavior of the electrical double-layer capacitor (EDLC). Meanwhile, the liquid agents showed the characteristics of a pseudocapacitor (PC) due to the redox response among the molecules and particles. The potential responses to extraneous stimuli relevant to the EIS properties, categorized as slow adaption (SA), fast adaption (FA), and other type (OT), were also analyzed in terms of the sensory response of the bio-inspired sensor. The categories were based on how the response was induced from the EIS properties. By controlling the EIS properties with different types of doping agents, sensors with various sensory responses become feasible.

Aging resistance under short time ultraviolet (UV) radiations of polymer wood composites entirely based on wastes

The paper studies the UV exposure influence on the mechanical properties, crystalline, interface and morphology of the optimised (previously water immersed) composites with wastes of rubber, PET, HDPE, wood and inorganic filler (CaO and fly ash). The mechanical strength, photo-degradation, crystalline structure and surface morphologies changes of the composites are evaluated after their exposure under simulated UV light and compared to unexposed ones. Experimental results showed UV exposure lead to the increase of Young moduli, compressive strength and tensile for high content PET samples. Significant mechanical strength even after water immersion and UV exposure were recorded for the rubber–PET–HDPE–wood–fly ash with a compression strength of about 70 MPa and for the 40 wt% PET composites with Young moduli of about 15 MPa. Therefore short term UV treatment could be used to enhance de composite’interface strength aiming at their outdoor applications.

Enhancing silica dispersion and interfacial interaction in styrene butadiene/silica rubber composites by using epoxidized styrene butadiene rubber as interfacial compatibilizer

AbstractIt is usually desired but often challenging to improve the wet traction, and reduce the abrasion and rolling resistance simultaneously in tread rubber, which is referred to as “magic triangle” in tire industry. To fulfill this goal, the filler dispersion and interfacial interaction required to be improved, as they are two essential factors to concurrently govern the ultimate properties of rubber composites. Herein, we synthesized the epoxidized solution polymerized styrene butadiene rubber (ESSBR) with different epoxy level, and used them as interfacial compatibilizer to promote the silica dispersion and silica/rubber interfacial interaction. The epoxy of ESSBR would react with silanol on silica surface and co‐crosslink with SSBR simultaneously, therefore build a strong bridge between rubber matrix and filler. By incorporation of 20 phr of ESSBR‐15% (15% of double bonds on main chain was epoxidized), the wet grip was improved by 40%, and DIN abrasion and rolling resistance were reduced by 38% and 21%, respectively with hardly sacrifice the mechanical properties. We envisage that this study provides an approach for the fabrication of rubber composites with improved silica dispersion and strengthened interfacial interaction.

Effects of Air Void Content, Crumb Rubber, and Pozzolanic Fillers on OGFC Laboratory Performance

Open-graded friction course (OGFC) is recognized for its ability for rapid stormwater drainage and effective noise reduction. Yet, several state highway agencies have limited its use because of concerns about its durability. The objective of this study was to investigate the impacts of air void (AV) reduction, crumb rubber (CR), and pozzolanic fillers on OGFC durability. Six mixtures were fabricated in the laboratory and their performance was evaluated. A control mix, 9.5-NMAS mix, two mixes incorporating CR, and two mixes prepared with pozzolanic fillers (i.e., Portland cement and fly ash) were evaluated. The test factorial was designed so that each mix would be evaluated at three different stages (i.e., production, construction, and field performance). A suite of laboratory tests was conducted including draindown, prediction of compaction effort, Cantabro abrasion loss, Hamburg wheel-tracking, Texas overlay tester, modified Lottman test, and boiling test to evaluate production, compaction, and OGFC resistance to raveling, permanent deformation, cracking, and moisture damage. Results showed that the reduction in AV and the use of CR and pozzolanic fillers considerably enhanced OGFC durability while maintaining appropriate functional performance (i.e., permeability).

Fill two needs with one deed: Simultaneous devulcanization and silica reinforcement of waste rubber for green tyre tread compound

The proper disposal of waste rubber without disturbing the environment is one of the most challenging tasks towards the researchers and scientists in the 21st century. The existing disposal techniques other than recycling of waste rubber goods, does not add any value either on the waste polymeric material or in the raw material from which those polymeric materials are originated. The mechanochemical devulcanization of waste natural rubber by bis(3-triethoxysilylpropyl)tetrasulfide and its subsequent dispersion in fresh natural rubber-silica composites in various proportions ranging from 20% to 70% wt% are both addressed in this investigation. The mechanical performance of the composites clearly indicates that tensile strength, tear strength and elongation at break gradually increases with increasing devulcanized rubber (r-NR) content up to a certain proportion and the values are much superior to that of the control formulation. The evaluated mechanical properties clearly specify that the optimum level of r-NR in the composite is 40 phr. The developed green composites showed superior thermal behavior compared to that of its control formulation. The rubber filler interaction between devulcanized natural rubber (r-NR) and silica was further explored by measuring the fraction of immobilized polymer chains using differential scanning calorimetry. Scanning electron microscopic images (SEM) of the r-NR based NR/r-NR/SiO2 composites reveal a homogeneous and uniform dispersion of the silica filler.

A comparative study for the main properties of silica and carbon black Filled bagasse-styrene butadiene rubber composites

A comparative study has been done to investigate the effect of carbon black (CB) and fumed silica (Si) on the physico-mechanical and thermal properties of Bagasse/styrene-butadiene rubber (B-SBR) composites. Based on the incorporation of 25 phr from natural ground bagasse powder (GBP) as a supplement reinforcing filler in styrene butadiene rubber (SBR) vulcanizates, two identical sets of formulations have been prepared using different concentrations (20, 40, 60 and 80 phr) of carbon black and silica as the main reinforcing fillers in SBR composites. The ground bagasse powder (GBP) employed in this work, has a selective grain size distribution ranging from about 20–180 μm. As well, 2.5 phr of maleic anhydride (MA) was incorporated to improve the interfacial adhesion between SBR and bagasse. The distinguishing effect of different fillers on the rheological properties was clearly established. Tensile strength, elongation at break, modulus at 100% elongation (M 100), hardness (Shore A), abrasion loss, degree of swelling, as well as, thermal gravimetric analysis (TGA) of the rubber vulcanizates were studied. The prepared samples were morphologically analysed by scanning electron microscopy (SEM). The tensile strength and M 100% values of carbon black-filled compounds were obviously higher than those of the silica filled ones. In addition, hardness, wear and swelling properties were improved more and more by increasing the filler content. Whereas, the Si filled B/SBR showed a decreasing trend in elongation at break values but with an evidently higher plateau than that of CB filled ones. Overall, the CB filled vulcanizates recorded dominant mechanical properties compared to the Si filled vucanizates. On the other hand, both fillers offered a noticeable improvement in thermal stability, but with a preference favored for the silica filled compounds. Furthermore, the findings for SEM were found to be in agreement with the observed mechanical properties. This study summarizes a detailed discussion of the emerging green technologies for tyre production and depicted comprehensive data from the available literature.

Evolution of the Viscoelastic Properties of Filler Reinforced Rubber under Physical Aging at Room Temperature.

Filler reinforced rubber is widely used for engineering applications; therefore, a sound characterization of the effects of physical aging is crucial for accurately predicting its viscoelastic properties within its operational temperature range. Here, the torsion pendulum is used to monitor the evolution of the storage and loss modulus of carbon black filled samples for four days after a temperature drop to 30 °C. The storage modulus presents a continuous increase, while the loss modulus generally displays a steady decrease throughout the four days that each test was conducted. The relationship of the recovery rates with the carbon black properties is also studied, analysing its dependency on the particle size and aggregate structure. The evolution of the recovery rate seems to depend linearly on the surface area while the carbon black structure appears to have a much weaker influence on the physical aging behavior for the set of compounds tested. The obtained results corroborate the presence of physical aging at room temperature for filler rubber materials and the ability of the torsion pendulum to monitor the storage and loss modulus change, providing pivotal data on the influence of physical aging on the viscoelastic properties of the material.

UNDERSTANDING RECOVERED CARBON BLACK

ABSTRACT As the rubber industry turns its focus to sustainability, recovered carbon black (rCB) has emerged as a commercial candidate to replace conventional fossil-based fillers. Since rCB is a new class of rubber filler, much is still to be understood regarding which of its properties influence final applications performance. The research presented in this paper demonstrates the importance of controlling the aggregate size distribution, silica content, carbonaceous residue content, and organic residue content in producing a consistent rCB product. These parameters are also demonstrated to be the fundamental reasons behind the disparity in performance of rCB and carbon black of similar colloidal properties. The findings of this study also reveal that the properties of an rCB can be tailored for a given application with precise control of the process conditions.

Effect of methyl methacrylate/nitrile rubber/graphene oxide on the anticorrosion and mechanical properties of epoxy‐based coating

AbstractGraphene oxide has a wide application prospect as filler due to its excellent physical blocking, coating reinforcement, and cathodic protection properties. However, graphene oxide is highly susceptible to agglomerative reunions. Three types of anti‐corrosion coatings were prepared on 5083 Al alloy by a simple smearing method. The coatings are based on neat epoxy resin by introducing different amounts of graphene oxide, methyl methacrylate/nitrile rubber, and methyl methacrylate/nitrile rubber/ graphene oxide fillers. Thermogravimetric analysis (TGA) results show that methyl methacrylate/nitrile rubber/graphene oxide fillers enhance the thermal stability of the epoxy resin‐based coatings. The SEM morphology shows the well‐dispersed methyl methacrylate/nitrile rubber/graphene oxide in the coating. The 2 and 1 wt% methyl methacrylate/nitrile rubber/graphene oxide coating exhibits excellent mechanical properties and outstanding anti‐corrosion properties, respectively. At 1 wt%, the OCP of the coating is −0.21 V. Additionally, the coating exhibits great anti‐corrosion performance after immersion for 196 h. Compared to the pristine coating and methyl methacrylate/nitrile rubber coatings, the methyl methacrylate/nitrile rubber/graphene oxide coatings show better thermal stability, mechanical properties and anti‐corrosion properties. The methyl methacrylate/nitrile rubber fillers degrade the thermal stability and anti‐corrosion protection and do not affect mechanical properties. Compared with graphene oxide coatings, the surface of methyl methacrylate/nitrile rubber/graphene oxide coatings is smoother with better dispersion, possessing better mechanical and anti‐corrosion properties though only a fewer amounts of graphene oxide were filled in epoxy resin. The better corrosion resistance of the coating can be attributed to the synergistic effect of a physical barrier and a coulomb block.

Assessment of the influence of electric arc furnace slag as a non-conventional filler for Nitrile Butadiene Rubber

Reinforcement of polymers by the addition of particles filler is a complex phenomenon that depends mainly on the hydrodynamic effect and a complex interplay between polymer, filler, and interfacial region. Mineral fillers are usually adopted as low-cost extenders due to their lower cost.In this study, the influence of a waste material such as electric arc furnace steel slag is assessed as filler for Nitrile-Butadiene Rubber following experimental procedures and analytical calculations adopted for traditional fillers. It was found that the slag content affects the static and the dynamic properties by increasing the material's capability to storage and dissipate energy. In addition to an important contribution of the hydrodynamic effect, the presence of an increasing immobilized rubber fraction around the slag particles (quantified by a differential scanning calorimetry analysis) plays a central role. The slag stiffens the NBR composite; the increase of static tensile and dynamic shear storage moduli was found to be consistent with the Halpin-Tsai and Guth-Gold prevision models respectively. Moreover, the non-linear dynamic behavior was found to be well-fitted by the Kraus equation models. The reinforcing ability of the slag particles as filler was confirmed by the negative slope of the Kraus plot on swelling data.

Natural Rubber Composites Using Hydrothermally Carbonized Hardwood Waste Biomass as a Partial Reinforcing Filler- Part I: Structure, Morphology, and Rheological Effects during Vulcanization.

A new generation biomass-based filler for natural rubber, 'hydrochar' (HC), was obtained by hydrothermal carbonization of hardwood waste (sawdust). It was intended as a potential partial replacement for the traditional carbon black (CB) filler. The HC particles were found (TEM) to be much larger (and less regular) than CB: 0.5-3 µm vs. 30-60 nm, but the specific surface areas were relatively close to each other (HC: 21.4 m2/g vs. CB: 77.8 m2/g), indicating a considerable porosity of HC. The carbon content of HC was 71%, up from 46% in sawdust feed. FTIR and 13C-NMR analyses indicated that HC preserved its organic character, but it strongly differs from both lignin and cellulose. Experimental rubber nanocomposites were prepared, in which the content of the combined fillers was set at 50 phr (31 wt.%), while the HC/CB ratios were varied between 40/10 and 0/50. Morphology investigations proved a fairly even distribution of HC and CB, as well as the disappearance of bubbles after vulcanization. Vulcanization rheology tests demonstrated that the HC filler does not hinder the process, but it significantly influences vulcanization chemistry, canceling scorch time on one hand and slowing down the reaction on the other. Generally, the results suggest that rubber composites in which 10-20 phr of CB are replaced by HC might be promising materials. The use of HC in the rubber industry would represent a high-tonnage application for hardwood waste.

Interplay of regio-selectively modified dendritic silica particles with styrene-butadiene rubber: The route towards better tires with lower rolling-resistance and higher grip

The current study presents for the very first time to our knowledge the synthesis, characterization, and application of regio-selectively modified dendritic silica particles (RMDS) in tire rubber composites. So far, no study has ever reported mesoporous silica bringing greater mechanical properties than small fractal precipitated silica. With mechanical testing (DMA, tensile strength) and advanced imaging (TEM-EDS, HIM-SIMS, micro-CT), it was demonstrated that dendritic particles enable superior mechanical reinforcement of rubber-based nanocomposites without any drawback as usually reported with fractal fillers. On one side, their modified porous surface mimics the porous aggregates formed by classic fillers, enabling the rubber chains to permeate the pores and closely interact with the particles. On the other side, unlike fractal fillers, RMDS consist of single particles instead of aggregates, and therefore do not suffer as much from the Payne effect and irreversible dislocations under mechanical solicitations. Also, the excellent dispersibility of RMDS allows to combine them with small amount of fractal filler. Dual filler composite shows superior mechanical performances versus materials using one filler family, leading to higher reinforcement, better traction and rolling resistance indicators. The use of porous particles as “unbreakable” fillers for rubber with a small amount of fractal silica as additive fillers paves the way for novel reinforcing dual-filler systems to be used in disruptive tires technology.