Incorporation of Oligomeric Hydrocarbon Resins for Improving the Properties of Aircraft Tire Retreads

This study focuses on the use of oligomeric hydrocarbon resins in order to benefit from their effect on improving the performance of aircraft tire retreads. The aim was to enhance the tackiness for the retreading process and their final performance in terms of superior stress–strain properties and low heat generation in order to decrease treadwear; thus, increasing the tire’s service life, and in terms of traction or skid resistance to improve safety during landing of an aircraft. Two types of resins are investigated: a terpene phenol and an aromatic hydrocarbon C9 resin, added to compounds with different filler systems: Carbon Black (CB), hybrid Carbon Black/Silica (CB/SI), and pure Silica (SI). The rubber compounds and vulcanizates are compared to their controls for each filler system. The use of resins improves processing independent of the filler system, with a slight improvement of tensile strength, Modulus at 300% (M300%) and Elongation at Break (EAB). The incorporation of resins improves the tackiness for the compounds with all filler systems, which is beneficial for the retreading process. A significant improvement in Ice Traction (ICT) and Wet Skid Resistance (WSR) with a trade-off in Heat Build-Up (HBU) is observed in CB- and CB/SI-reinforced compounds when resins are added. Terpene phenol and aromatic hydrocarbon C9 resin show comparable ICT, while the aromatic hydrocarbon C9 resin gives a better WSR performance than the terpene phenol in all compounds. However, a slight improvement in HBU with the use of both resins is only observed in the SI-filled system. The present exploratory study into the addition of resins demonstrates the potential to significantly improve the overall performance of aircraft tire retreads, justifying more in-depth investigations into this possibility in real tires.

Multiple Intermolecular Interaction to Improve the Abrasion Resistance and Wet Skid Resistance of Eucommia Ulmoides Gum/Styrene Butadiene Rubber Composite

A rubber composite was prepared by using methyltriethoxysilane (MTES) to modify silica (SiO2) and epoxidized eucommia ulmoides gum (EEUG) as rubber additives to endow silica with excellent dispersion and interfacial compatibility under the action of processing shear. The results showed that compared with the unmodified silica-reinforced rubber composite (SiO2/EUG/SBR), the bound rubber content of MTES-SiO2/EEUG/EUG/SBR was increased by 184%, and its tensile strength, modulus at 100% strain, modulus at 300% strain, and tear strength increased by 42.1%, 88.5%, 130.8%, and 39.9%, respectively. The Akron abrasion volume of the MTES-SiO2/EEUG/EUG/SBR composite decreased by 50.9%, and the wet friction coefficient increased by 43.2%. The wear resistance and wet skid resistance of the rubber composite were significantly improved.

The effect of silica modified by deep eutectic solvents on the properties of nature rubber/silica composites

The effect of deep eutectic solvent (DES) modified silica on the properties of nature rubber (NR) composites were investigated. The DES is an environment-friendly and low-cost solvent, which was prepared by mixing choline chloride and urea in a 1:2 molar ratio. The NR composites filled with DES modified silica were prepared and the properties were tested. The interaction between the DES and silica were characterized by Fourier transform infrared spectroscopy (FTIR), the interaction between silica and silica were tested by differential scanning calorimetry (DSC). The dynamic properties, such as rolling resistance and wet skid resistance, and were tested by dynamic mechanical analysis (DMA). Morphologies of the composites were characterized by scanning electron microscopy (SEM). The results indicate that the DES can interact with silica by hydrogen bond to improve the compatibility between the rubber and silica. When the content of DES was 3 phr, the tensile strength, modulus at 300%, tear strength, and the crosslinking density of the composites was increased. At the same time, the proper content of DES can reduce the rolling resistance of the vulcanized rubber while maintaining good wet skid resistance.

Maleic Anhydride Modified Dicyclopentadiene Resin for Improving Wet Skid Resistance of Silica Filled SSBR/BR Composites

As commercial rubber in tires, silica-filled solution-polymerized styrene-butadiene rubber/butadiene rubber (SSBR/BR) compounds exhibited preferable wet skid resistance (WSR) properties, which could be further enhanced by the incorporation of some oligomeric resins. However, the untreated dicyclopentadiene (DCPD) resin shows a slight improvement in wet friction even if the good compatibility between DCPD and SBR owing to their common cyclic structures. For this problem to be addressed, we aimed to enhance its resin-silica interaction by reaction with maleic anhydride (MAH). In detail, the effect of MAH content on WSR, curing characteristics, physical-mechanical properties of the silica-filled SSBR/BR composites was investigated. When the MAH content is 4 wt% in the modified DCPD resin, the maximum enhancement of about 15% in tan δ values at 0 °C, as well as that of 17% in British pendulum skidding tester (BPST) index is obtained, indicating a desirable improvement in WSR. In addition of these two commonly used methods, water contact angles of the vulcanizates increase gradually with increasing MAH content, further confirming the remarkable performance of modified DCPD resin in WSR.

ENHANCING PERFORMANCE OF SILICA-REINFORCED NATURAL RUBBER TIRE TREAD COMPOUNDS BY APPLYING ORGANOCLAY AS SECONDARY FILLER

ABSTRACT Silica-reinforced natural rubber (NR) tire tread compounds are investigated using organoclay (OC) as secondary filler. By varying mixer temperature settings at a silica/OC ratio of 45/10 phr, dump temperatures are reached of approximately 120, 140, 150, and 160 °C. The increased dump temperature leads to a better silanization reaction resulting in lower mixing torque, Mooney viscosity, and Payne effect. The optimum mixing dump temperature was found to be around 150 °C. By varying the loadings of OC in the silica-filled NR compounds from 0 to 36 wt% relative to total filler amount, the increased OC loadings decreased the Payne effect and compound viscosities, significantly shortened scorch and cure times, and raised the tan delta at −20 and 0 °C as indications for ice traction and wet skid resistance of tire treads made therefrom. The optimum loading of OC of 18 wt% relative to total filler content shows better Payne effect, cure rate index, tan delta at −20 and 60 °C indicative for rolling resistance, and DIN abrasion resistance index. The results indicate that the use of this hybrid filler may provide tires with better wet traction and lower rolling resistance and wear resistance compared with the pure silica-filled system.

Effect of Graphene Oxide Modified with Organic Amine on the Aging Resistance, Rolling Loss and Wet-Skid Resistance of Solution Polymerized Styrene-Butadiene Rubber

Graphene oxide (GO) was modified by p-phenylenediamine (PPD), aiming at improving the wet-skid resistance and reduce the rolling loss of solution polymerized styrene-butadiene rubber (SSBR). PPD with amino groups enabled GO to obtain anti-aging function. The structure of modified GO (PPD-GO) was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Raman spectroscopy. Mechanical tests showed that the mechanical properties of SSBR before and after aging were improved by adding PPD-GO. The results of thermogravimetric-differential scanning calorimeter synchronization analysis (TGA-DSC) indicated that SSBR/PPD-GO obtained good thermo-oxidative stability. The dynamic mechanical analysis (DMA) of SSBR composites showed that the mechanical loss factor (tanδ) peak moved to high temperature with the content of PPD-GO. The tanδ values of SSBR composites showed that it had a good effect on improving the wet-skid resistance and reducing the rolling loss of SSBR by adjusting the content of PPD-GO. In particular, with the addition of 4 phr GO, SSBR was effectively improved in mechanical properties, aging resistance, wet-skid resistance and low rolling loss.

ELASTOMERIC NANOPARTICLES: EFFECTIVE ADDITIVE FOR HIGH PERFORMANCE RUBBER NANOCOMPOSITES

ABSTRACT The “magic triangle” is the most important challenge to rubber composites for the automobile industry. According to the magic triangle, it is difficult to improve the rolling resistance (energy saving), wet skid resistance (safety), and wear (life) of a tire simultaneously. However, ∼5% decrease of rolling resistance, >20% increase of wet skid resistance, and 15% decrease of wear were achieved after adding a small amount of elastomeric nanoparticle (ENP). The effect of ENP on the performances of rubber composites was expounded by characterization of the dispersion of filler and the relationship between filler and rubber. The main difference between ENPs and other nanoparticles was that ENPs acted as not only a part of filler but also as a part of rubber in rubber composites.

Preparation and Performance of Silica/ESBR Nanocomposites Modified by Bio-Based Dibutyl Itaconate

Ester-functionalized styrene-butadiene rubber (dibutyl itaconate-styrene-butadiene rubber) (D-ESBR) was synthesized by low-temperature emulsion polymerization using dibutyl itaconate (DBI) as a modified monomer containing ester groups. Nonpetroleum-based silica with hydroxy groups was used as a filler to enhance the D-ESBR, which can provide excellent mechanical properties, low rolling resistance, and high wet skid resistance. During the preparation of the silica/D-ESBR nanocomposites, a hydrogen-bonding interface was formed between the hydroxy groups on the surface of silica and the ester groups in the D-ESBR macromolecules. As the content of ester groups in the D-ESBR increases, the dispersion of silica in the nanocomposites is gradually improved, which was verified by rubber process analyzer (RPA) and scanning electron microscopy (SEM). Overall mechanical properties of the silica/D-ESBR modified with 5 wt % DBI were improved and became superior to that of the non-modified nanocomposite. Compared with the non-modified silica/D-ESBR, the DBI modified silica/D-ESBR exhibited a lower tan δ value at 60 °C and comparable tan δ value at 0 °C, indicating that the DBI modified silica/D-ESBR had lower rolling resistance without sacrificing wet skid resistance.