Lower Heat Build-up Research Articles

Green and energy-saving tread rubber by constructing chemical cross-linking interface between graphene oxide and natural rubber

The dispersibility of fillers and interfacial interaction are crucial for polymer nanocomposites. Developing a simple, efficient and green method to simultaneously reduce and functionalize graphene oxide (GO) for preparing graphene/rubber composites with excellent dispersibility and enhanced interfacial interactions remains one of the main trends in developing and expanding the application of graphene in the rubber industry. In this work, VOC (volatile organic compound) -free and environmentally friendly L-methionine (L-Met) was selected as the functional modifier of GO. Then, L-Met-modified GO (MGO) was blended with natural rubber (NR) in an aqueous phase to prepare MGO/NR composites. The amphiphilic property of L-Met not only reduced GO but also endowed it with less agglomeration and excellent water dispersibility, which was a prerequisite for achieving uniform dispersion of GO in the NR matrix. In addition, the amino acids on the surface of MGO enhanced the compatibility between GO and the protein-phospholipid layer on the outer layer of NR latex particles. Meanwhile, L-Met containing sulfur bonds promoted rubber vulcanization, resulting in the formation of a cross-linked network between the modified GO and NR molecular chains. Compared to unmodified GO/NR composites, MGO/NR composites exhibited excellent mechanical properties and low heat build-up. More importantly, the solid tire prepared by using L-Met as the interface modifier for GO filled rubber showed lower rolling resistance and temperature rise, and the energy saving efficiency was improved. This strategy is expected to provide a new insight into the green production of organically modified graphene and the preparation of low-energy-consumption green graphene tires.

Novel Design of Eco-Friendly High-Performance Thermoplastic Elastomer Based on Polyurethane and Ground Tire Rubber toward Upcycling of Waste Tires.

Waste rubber tires are an area of global concern in relation to reducing the consumption of petrochemical products and environmental pollution. Herein, eco-friendly high-performance thermoplastic polyurethane (PU) elastomers were successfully in-situ synthesized through the incorporation of ground tire rubber (GTR). The excellent wet-skid resistance of PU/GTR elastomer was achieved by using mixed polycaprolactone polyols with Mn = 1000 g/mol (PCL-1K) and PCL-2K as soft segments. More importantly, an efficient solution to balance the contradiction between dynamic heat build-up and wet-skid resistance in PU/GTR elastomers was that low heat build-up was realized through the limited friction between PU molecular chains, which was achieved with the help of the network structure formed from GTR particles uniformly distributed in the PU matrix. Impressively, the tanδ at 60 °C and the DIN abrasion volume (Δrel) of the optimal PU/GTR elastomer with 59.5% of PCL-1K and 5.0% of GTR were 0.03 and 38.5 mm3, respectively, which are significantly lower than the 0.12 and 158.32 mm3 for pure PU elastomer, indicating that the PU/GTR elastomer possesses extremely low rolling resistance and excellent wear resistance. Meanwhile, the tanδ at 0 °C of the above-mentioned PU/GTR elastomer was 0.92, which is higher than the 0.80 of pure PU elastomer, evidencing the high wet-skid resistance. To some extent, the as-prepared PU/GTR elastomer has effectively solved the "magic triangle" problem in the tire industry. Moreover, this novel research will be expected to make contributions in the upcycling of waste tires.

Novel polybutadiene rubber with long cis-1,4 and syndiotactic vinyl segments (CVBR) for high performance sidewall of all-steel giant off-the-road tire

The novel polybutadiene rubbers (CVBR) carrying 88–97% of long cis-1,4 polybutadiene segments (cis-PB, cis-1,4 content >98.3%) and 3–12% of long syndiotactic1,2-polybutadiene segments (sPB, 1,2 content >87.0%) could be successfully synthesized via in-situ coordination polymerizations of butadiene in hexanes in our lab and also be scaled up via continuous polymerization process in pilot (scale: 200 t/a). The natural rubber (NR)-based compound formulations containing different contents of CVBR, and carbon black (CB) fillers were developed and the optimized NR/CVBR/CB vulcanizates with 40% of CVBR were manufactured for the sidewall of all-steel giant off-the-road tire. The storage modulus of NR/CVBR/CB compounds and the elastic modulus, tensile strength and tear strength of NR/CVBR/CB vulcanizates could be remarkably increased by increasing CVBR content. The crack generation and growth could be effectively restricted due to both the fast relaxation, the rigid polymer-filler interface and synergistic effect of high cis-polybutadiene and crystalline 1,2-polybutadiene particles on the strain-induced crystallization behaviors of rubber matrix. The heat build-up of NR/CVBR/CB vulcanizates could be greatly reduced by introduction of cis-PB segments in CVBR for the easy mobility and low hysteresis of macromolecular chains. The NR/CVBR/CB vulcanizates with high strength and elastic modulus, good flex fatigue crack resistance and low heat build-up would meet the requirement for high performance sidewall in manufacturing giant all-steel off-the-road tires.

Synergistic effect of Tween 20 and TESPT compatibilizers on the performance characteristics of latex imprinted silica-reinforced green tyre tread formulation

The present study has a prime goal to develop a green tyre tread formulation with enhanced performance characteristics including low rolling resistance, improved wet grip, low heat build-up and enhanced mechanical properties which are essential for a high-performance tyre tread compound. A base formulation of natural rubber/polybutadiene (NR/BR) blend with minimum carbon filler was formulated initially without compromising the physical properties much by balancing the properties by incorporating precipitated silica. Enhanced surface area for silica was obtained through the latex imprinting method which had an ultimate effect on the interaction between the matrix macromolecules and filler particles positively. Further, ENR was used as a compatibilizing agent to upgrade physical properties in terms of 20% improvement in tensile and around 10% improvement in tear strength. Additional improvement in physical as well as rolling resistance performance was achieved via the incorporation of coupling agents including TESPT and polyoxyethylene(20) sorbitan monolaurate (Tween 20). Apart from the improvement in mechanical properties, rolling resistance and heat build-up properties are promising for the final tyre tread formulation as both the values tend to reduce considerably by 35% and 63% respectively concerning the base formulation.

Improvement of mechanical and dynamic properties of high silica filled epoxide functionalized natural rubber

In this research, 3 different low degrees (4, 8, and 14 mol%) of epoxide functionalized natural rubber were prepared via chemical modification of natural rubber, which was then vulcanized. Each of them was mixed with silica (50 parts per hundred of rubber) without a silane coupling agent and investigated their properties. It was found that the tensile and tear properties, as well as abrasion resistance of the silica filled epoxide functionalized natural rubber vulcanizates were higher than the silica filled natural rubber vulcanizate. These properties improvements could be attributed to the interaction of the silanol groups of the silica with the epoxide groups of the modified rubber chains via chemical and physical interactions. This could be supported by the occurrence of tear parts from the morphology investigation of the tensile fractured surface of the modified rubber vulcanizates using a scanning electron microscope. The presence of silicon elements in the rubber matrix was evidenced by scanning electron microscopy and energy dispersive X-Ray spectrometer. Moreover, the silica filled epoxide functionalized natural rubber having 14 mol% epoxide content without a silane coupling agent exhibited low abrasion loss, low heat build-up and enhancement in loss tangent at 0 °C, hence improved wet skid resistance, compared to the silica filled natural rubber without a silane coupling agent. This work demonstrated that the prepared low degree of epoxide functionalized natural rubber could be potentially applied to the tire tread rubber application without the use of a silane coupling agent.

Multifunctional and anti-migration plasticizers based on bio-based phenol-functionalized liquid 1,2-polybutadiene

With the increasing demands for environmental friendliness, bio-based additives in rubber materials have attracted extensive research attention from the academy and industry. However, the low molecular weight and high polarity are detrimental to mixing compatibility with rubber materials. In this work, we prepare a phenol-functionalized 1,2-PB (1,2-PB-g-CA) by grafting bio-based cardanol onto 1,2-polybutadiene rubber (1,2-PB) based on the olefin metathesis. The 1,2-PB-g-CA demonstrate a controlled number average molecular weight from 7 × 103 to 4 × 104 and tuned functionality from 0% to 20%. The open reaction system exhibited a higher functionality due to the removal of small molecules. The 1,2-PB-g-CA was used as a plasticizer for silica filled styrene-butadiene rubber (SBR). The enhanced interfacial interaction between phenolic hydroxyl groups of cardanol and the silanol groups of silica significantly increased the compatibility of silica and rubber matrix. Compared with the common paraffinic oil, the obtained SBR/silica compounds were afforded low rolling resistance, high wet grip, and low heat build-up. Moreover, the 1,2-PB-g-CA showed better anti-migration properties. Therefore, our preparation method of bio-based modified liquid rubber has broad application prospects in high-performance “green tire.”

Tuning the low rolling resistance, wet grip, and heat build‐up properties of tyre tread formulations using carbon black/thermally exfoliated graphite hybrid fillers

AbstractEcofriendly green tyre tread compounds were developed with low rolling resistance, low heat buildup, and improved wet grip properties. A standard formulation of natural rubber (NR) and butadiene (BR) with 50 phr carbon black was prepared in a brabender plasticoder. Based on the processability, successful reduction of carbon black and aromatic oil content was done up to a minimum value of 32 and 3 phr respectively. Partial replacement of graphite with carbon black was done to achieve the optimized formulation. A binary filler system with 10 phr graphite and 22 phr carbon black was optimized based on the mechanical properties and further addition of graphite leads to reduction in properties due to agglomeration. To enhance the properties further, the graphite was thermally treated to get an exfoliated structure which can significantly improve the area of the filler/matrix macromolecules interface. This ultimately had a positive impact on targeted properties. A sudden thermal shock for 15 min at various temperatures ranging from 400 to 550°C was given and prepared the optimized binary formulation and evaluated the properties. Excellent results in terms of low rolling resistance (0.039) and heat build‐up (18°C) were recorded for final formulation. The flex fatigue resistance was enhanced and the thermal stability improved by 29°C.

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.

Improved mechanical, thermal conductivity and low heat build-up properties of natural rubber composites with nano-sulfur modified graphene oxide/silicon carbide

It is still a bottleneck to simultaneously attain enhanced mechanical properties, thermal conductivity and low heat build-up properties for graphene-rubber composites obtained by conventional fabrication processes. The critical elements to enhance the comprehensive performance of rubber include excellent dispersion and the interaction of filler and matrix. In this work, the increased filler structure degree with point-surface structured SiC/GO (SG) and the strong interface modified with nano-sulfur synergistically improve the dispersibility and interfacial interaction, which effectively achieves excellent integrated performance at low filler content. More importantly, nano-sulfur not only acts as a modifier to improve interfacial compatibility, but also has a vulcanization function that enables SG and natural rubber (NR) molecular chains to form a uniformly distributed cross-linked network structure. Consequently, only when 4 phr of SiC/GO-S (SG-S) filler was added to NR, the tensile strength, thermal conductivity and low heat generation properties are higher than those of NR/GO rubber by 22.5%, 21.2% and 8.3%. Therefore, this work may open new horizons for the development of green tire.

Introduction to the New Copolymer of Chloroprene and Acrylonitrile with Differentiated Properties

The random copolymer of chloroprene and acrylonitrile is a newly developed rubber whose features and value propositions are not scientifically explored yet. This article focuses on the basic characterizations and properties of acrylonitrile-chloroprene rubber. Qualitative analyses through infrared (FTIR) and nuclear magnetic resonance (1H-NMR) spectra confirm the presence of both the -Cl and -CN groups in the new rubber. As evidenced through differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA), the single glass transition temperature of acrylonitrile-chloroprene rubber reflects its monophasic random microstructure. While compared against commercial grades of chloroprene rubber (CR) and nitrile rubber (NBR), the new rubber provides a distinctive combination of properties that are not available with either of the elastomer alone. Acrylonitrile-chloroprene rubber demonstrates slightly lower specific gravity, an improved low-temperature compression set, higher flex-fatigue resistance, and lower volume swelling in IRM 903 and Fuel C to chloroprene rubber. As compared to nitrile rubber, the new copolymer shows appreciably better heat aging and ozone resistance. Good abrasion resistance, low heat buildup, and remarkably high flex-fatigue resistance indicate excellent durability of the acrylonitrile-chloroprene rubber under dynamic loading. Based on the preliminary results, it is apparent that the new copolymer can be a candidate elastomer for various industrial applications which demand good fluid resistance, high heat and low-temperature tolerances, good weatherability, and durability under static and dynamic conditions.

Wet Mixing with Organic Solvent for Synthesized cis-1,4-Polyisoprene-Based Rubber Composites.

In this work, well-dispersed fumed SiO2/cis-1,4-polyisoprene rubber (IR) masterbatch was first obtained through an effective wet mixing method, and the properties of the corresponding vulcanizate were studied. Before curing with activator and sulfur, IR solution was blended and co-coagulated with SiO2 suspension modified by bis(3-trimethoxysilypropyl) tetrasulfide in n-hexane. The modification of TESPT imparted evenly distributed SiO2 particles in IR and improved interfacial binding among SiO2 and IR. Hence, the prepared compound presented better processability and the corresponding vulcanizate presented higher physical performance, including higher tensile strength, lower heat buildup, and better fatigue resistance than that prepared in the dry mixing method. Additionally, higher wet skid resistance and lower rolling resistance could be observed in fabricated SiO2/IR vulcanizate. The employed wet mixing method is economical and efficient, which is promising in preparing rubber composites with comprehensive performance.

Dodecanol and KH-592 Co-Modify Silica to Prepare Low Heat Build-Up and High Performance Natural Rubber Composites

Friction between filler/filler and filler/matrix in rubber composites is the main factor affecting the heat build-up. In this study, we used dodecanol and silane coupling agent KH-592 to co-modify silica to prepare silica/natural rubber (NR) composites. When dodecanol and KH-592 are grafted onto the surface of silica at the same time, dodecanol can also shield part of the hydroxyl groups by its molecular chain length, which further improves the dispersibility of silica particles. The silane coupling agent KH-592 can form a bridge structure between the silica and the NR matrix under the action of a mercapto group, and improve the interaction between the filler and the matrix. By controlling the use ratio of dodecanol and KH-592, the dispersion of the filler and the interaction between the filler and the matrix can be adjusted. Thereby, the friction between the filler/filler and the filler/matrix is reduced, and a low heat build-up rubber composite material is prepared. Through co-modification, we prepared a series of low-heat build-up silica/NR composites, where the minimum heat generation reached 13∘C. The co-modified silica/NR composite material not only meets the requirements of green tires, but also has low heat build-up characteristics, providing a new strategy for preparing green and energy-saving tires.

Stable ion bond for high damping, high wet resistance, and low rolling resistance high vinyl polybutadiene rubber‐based dicarboxylate ionomer

AbstractSince the implementation of European Union (EU) tire label, the focus of recent attention has been focused on high performance green tire with low rolling resistance, high wet resistance, low noise, and excellent auto‐braking properties. However, it is a significant challenge to simultaneously achieve these performances for rubber materials. In this research, we developed a novel concept on the construction of stable ion bonds for high performance high vinyl polybutadiene rubber (HVBR)‐based dicarboxylate ionomers. HVBR‐based dicarboxylate sodium ionomer (hereafter referred as Na ionomer) was fabricated through complexation reaction of some or all of carboxylic functional groups on the preprepared maleinized HVBR molecular chains with sodium hydroxide. In the case of Na ionomers, the formation of sodium carboxylate group was certified from Fourier transform infrared spectra. Physical and dynamic mechanical measurements indicated that the tensile strength, wear resistance, wet skid resistance, dry sliding resistance, low rolling resistance, and low heat buildup of the Na ionomer were significantly improved compared to that of HVBR, and Na ionomer simultaneously showed better damping properties and the effective damping temperature range was broadened from −8.8 to 30.1°C, which was closer to the room temperature. Consequently, the approach and results collectively represent a significant advance toward the development of high performance green tire rubber materials.

The Influence of Trans-1,4-poly(butadiene-co-isoprene) Copolymer Rubbers (TBIR) with Different Molecular Weights on the NR/TBIR Blends

The molecular weight of a polymer is of prime importance and greatly influences the processing and mechanical properties of the polymer. Trans-1,4-poly(butadiene-co-isoprene) multi-block copolymer rubbers (TBIR) exhibit outstanding fatigue resistance, low heat build-up and good abrasion resistance, and are expected to be desirable candidate for high performance tire. Study on the influence of TBIR with different molecular weights on the structure and properties of TBIR and natural rubber (NR)/TBIR blends is essential to understand its contribution to the greatly improved dynamic properties of the rubber vulcanizates. TBIR with different molecular weights characterized by 1H-NMR, 13C-NMR, GPC, and DSC were highly trans-1,4-copolymers with similar chain sequence distribution and crystalline trans-1,4-polyisoprene (TPI) blocks. The green strength and modulus of TBIR increased with the increasing molecular weight. The NR/TBIR compounds filled with 40 phr carbon black were chemically cured by sulfur for the preparation of NR/TBIR vulcanizates. The compatibility between NR and TBIR, filler distribution, crosslinking bond and density, and properties of NR/TBIR vulcanizates were studied. The NR/TBIR vulcanizates showed increasing tensile strength, hardness, modulus, rebound, abrasion resistance, and flexural fatigue properties with increasing molecular weight of TBIR. Furthermore, they presented significant improvement in flexural fatigue resistance when compared with that of NR vulcanizate. The contribution mechanism of TBIR on the NR/TBIR blends was discussed. The TBIR with a wide range of molecular weight are ideal rubbers for high performance tires.

Effect of electronegativity and steric hindrance of the cocatalyst on the activity and selectivity of butadiene polymerization catalyzed by molybdenum

ABSTRACTMolybdenum‐based random 1,2‐polybutadiene (1,2‐PB) rubber, with its excellent wet skid resistance, low rolling resistance, and low heat buildup, can be used for green tread rubber, and it has significant benefits for the enhancement of the mechanical strength of 1,2‐PB. In this study, we investigated in detail the effects of the electronegativity and steric hindrance of the cocatalyst on the stereoselectivity of the resulting polymers. In the case of cocatalysts with moderate electronegativities, the active centers were more stable; this resulted in a larger molecular weight and a higher conversion, whereas a cocatalyst with excessive electronegativity tended to initiate cationic polymerization. The high sterically hindered substituent restricted the coordination configuration of the monomer; this ultimately resulted in the increase in the 1,2 structure to 90%. Fourier transform infrared analysis showed that the content of trans‐1,4 structure increased from 7 to 66%, and its crystallinity reached 59.2%, as calculated with differential scanning calorimetry when triethyl aluminum was used as the cocatalyst. Consequently, trans‐1,4‐polybutadiene crystals were introduced into the 1,2‐PB elastomer in one step; this could be a promising facile route for strengthening 1,2‐PB. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46906.

Effects of Replacement of Part of the Silica Reinforcement with Hybrid Modified Microcrystalline Cellulose on the Properties of their Rubber Composites

ABSTRACTHybrid modified microcrystalline cellulose (HMCC), with SiO2 nanoparticles being in-situ loaded on the surface of microcrystalline cellulose (MCC), was obtained through a sol-gel process of tetraethoxysilane (TEOS) by using ammonia as catalyst. HMCC was characterized by thermogravimetric analysis and scanning electron microscopy. The results showed that the spherical nano-SiO2 particles had been loaded successfully on the surface of the MCC with a loading ratio of approximately 10%. Then the HMCC was used in high vinyl solution-polymerized styrene butadiene rubber (SSBR)/silica compounds to replace part of the silica, and its effects on the physio-mechanical and dynamic mechanical properties of the vulcanizates were investigated. The results showed that the HMCC samples had improved physio-mechanical properties and lower heat build-up than that of MCC ones. Dynamic mechanical analysis (DMA) showed that the tanδ value of the compounds decreased at 60°C while increased obviously at 0°C, which meant that the tires would have improved wet-skid resistance while maintaining low rolling resistance when HMCC was used in tire tread compounds. As observed from scanning electron microscopy (SEM) photos, the sizes of the HMCC were in-situ decreased from 20–90 µm to 0.5–10 µm during the processing of the rubber compounds. Compared with MCC, the interfacial adhesion between HMCC and rubber was also improved greatly.

Synergistic effect of CB and GO/CNT hybrid fillers on the mechanical properties and fatigue behavior of NR composites.

In this paper, graphene oxide (GO) and carbon nanotube (CNT) hybrid fillers were used to replace partial carbon black (CB), and GO/CNT/CB/NR composites were prepared with excellent crack growth resistance, low heat build-up and superior mechanical properties. Mechanical testing revealed a significant synergistic reinforcement between GO/CNT and CB in NR composites. The improved dispersion of GO/CNT hybrid fillers and CB in the NR matrix was characterized by transmission electron microscopy (TEM). Through the fatigue test, the GO/CNT/CB/NR composites showed excellent fatigue crack growth resistance and low heat build-up compared to CB/NR composites. These properties provide the NR composites with better applications in industry.

Influence of graphene oxide and multiwalled carbon nanotubes on the dynamic mechanical properties and heat buildup of natural rubber/carbon black composites

In this study, graphene oxide (GO) and multiwalled carbon nanotubes (MWNTs) were incorporated into natural rubber (NR) to study the influence of each of these materials when substituted for carbon black (CB) on the structure and properties of NR/CB composites. The influence of stirring time on the composites used to prepare the masterbatch was also studied. Morphological observations revealed that the dispersion of the filler was improved by partially substituting GO and MWNTs for CB. Improvements in the static mechanical properties and dynamic properties were achieved when the concentration of GO or MWNTs was 1 phr. The highest modulus and hardness was found in the composites with a short stirring time used for the preparation of the masterbatch. When compared to CB-filled vulcanizates, composites with GO had a greater tensile strength and equivalent heat buildup, which is mainly attributed to the larger cross-link density. In this article, compared with the MWNTs, GO is more beneficial to the preparation of rubber composite with high mechanical properties and low heat buildup. This is mainly due to the common functional groups carboxyl, hydroxyl, and epoxide in the GO can improve the dispersion of GO within a matrix.

Role of Rubber Stiffness and Surface Roughness in the Tribological Performance on Ice

ABSTRACTThe aim of this work is to investigate the effect of slider surface roughness and stiffness on the friction between rubber compounds and ice surfaces in order to provide insight into rubber–ice friction generation mechanisms. For this purpose, rubber compounds were designed to have different levels of macroscopic roughness and cured stiffness by modifying the filler system and plasticizer loading. In order to accurately evaluate the effects of surface and bulk rubber property on ice friction, linear friction tests were performed on laboratory ice with varied frictional heat buildup by modifying the friction test protocol. The results showed that the friction force was in general increased through the ploughing effect of a rough rubber block sliding on smooth ice. The increase in friction by ploughing was more pronounced when the contacting rubber block had sufficiently low stiffness and when the accumulation of frictional heat on ice was sufficiently high. It was also evidenced that a sufficiently hard rubber with test conditions leading to low heat buildup on ice could nevertheless lead to an opposite influence of roughness on rubber–ice friction; that is, lower friction force with a slider with a higher roughness.

Studies on natural rubber containing kaolin modified with hexamethylenediamine derivative of phosphorylated cashew nut shell liquid prepolymer

Kaolin was modified with a solution of phosphorylated cashew nut shell liquid prepolymer (PCNSL) containing hexamethylenediamine (HMDA). The organomodified kaolin was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and infrared spectroscopy (FTIR). Processability characteristics and physico-mechanical properties of natural rubber (NR) compositions of conventional vulcanization (CV), semi efficient vulcanization (SEV) and efficient vulcanization (EV) systems containing 6phr (parts per hundred rubber) of the HMDA-PCNSL modified kaolin and unmodified kaolin have been studied. Compositions containing the organomodified kaolin showed improved cure characteristics and vulcanizate properties such as hardness, tensile strength, tear strength, abrasion resistance and thermal stability along with lower heat build-up and compression set which could be advantageous for applications such as tire treads.