Query: RPA，rubber

title: Direct Measurement of Steady Shear Viscosity at High Shear Rates Using RPA
abstract: The characterization of the viscosity of rubber compounds is necessary for fully optimizing processing conditions. Measurement techniques for viscosity often include capillary rheology and dynamic oscillatory testing in an open or closed boundary rheometer. Due to the strain dependent nature of filled elastomer compounds, the Cox Merz relationship, which is often used to correlate dynamic viscosity with steady shear viscosity, does not hold and the dynamic viscosity values typically do not match the capillary rheometer. In this paper, we present a new method for directly measuring steady shear viscosity using a rubber process analyzer (RPA)

title: Enhancing Performances of Polyamide 66 Short Fiber/Natural Rubber Composites via In Situ Vulcanization Reaction
abstract: This paper details a new method for improving the interfacial bonding between PA66 short fiber (PSF) and natural rubber (NR) by reaction of the methacrylic acid (MAA) grafting modified PSF with rubber during vulcanization. Carbon carbon double bonds introduced to the SF surface by MAA grafting were opened, and a vulcanization reaction occurred between the modified PSF and rubber in the presence of sulfur. The chemical reactions were verified by FTIR and XPS. The processing rheological behaviors of the compounded composites were investigated by a rubber processing analyzer (RPA) The morphology of modified PSF was characterized by AFM and SEM. The improved interfacial bonding was confirmed by DMA, which enhanced deformational stress at definite elongation of the NR/PSF composites. The volume concentration of the MAA solution for grafting on the SF surface had a great influence on the interfacial bonding and mechanical properties of the composites; when the volume concentration was 30 the modified PSF reinforced NR/CB had the best interfacial bonding and mechanical properties.

title: Correlations between the Hysteresis Parameters Determining the Rolling Resistance in Rubber Composites
abstract: Recently, the research on low rolling resistance tires attracted interest for its reduction of petrol consumption, which is related to the hysteresis loss of rubber composites. Here, four common methods representing the hysteresis loss of rubber composites in lab were contrasted to explore the potential connections between them. The results indicated that tan d obtained by DMA showed good positive linearity with that obtained by RPA without distinguishing the rubber species and filler types, also for the positive relation between tan d and hysteresis loop area (HLA) The rolling power loss (L) captured by the rolling resistance testing machine appeared to have a positive correlation with tan d from DMA or RPA in NR composites, while a negative connection showed up in SBR composites. Further, considering the influence of strain on rolling energy loss, the 100% modulus was introduced leading to a good positive quadratic equation connection between tan d/100% modulus and L in all common rubber composites.

title: Preparation, carbon black dispersibility and performances of novel biobased integral solution polymerized styrene butadiene rubber with b myrcene bottlebrush segments
abstract: A series of green myrcene based styrene butadiene integral rubber were designed and prepared by anionic solution polymerization for solving the fossil depletion and achieving the excellent comprehensive performances, including SBR (75) MR (25) r SBMR, b SBMR and s b SBMR. The RPA, SAXS, SEM and TEM results revealed that flexible side chain in myrcene bottlebrush segments, which was beneficial to spread and infiltrate on the surface of the filler, could significantly improve carbon black (CB) dispersibility and inhibit the strong filler filler interactions. The degree of improvement in CB dispersibility can be ranked as follows: SBR (unmodified rubber) SBR (75) MR (25) (mechanical blending rubber) r SBMR (26) (random copolymerized rubber) b SBMR (26) (block copolymerized rubber) s b SBMR (26) (star block copolymerized rubber) Furthermore, for the star shaped integral rubber, rolling resistance decreased by 40.2% wet skid resistance increased by 74.8% and elongation at break increased by 8.30% without sacrificing the physical and mechanical properties compared with the unmodified SSBR/CB composites. The results show that the chain segment of the bottlebrush structure has reasonably obvious advantages over than that of the random distribution structure in improving the dynamic mechanical properties of rubber. On the basis of aforementioned assessment, we believe that CB reinforced b myrcene based styrene butadiene integrated rubber is a versatile and promising candidate for future tire tread elastomers.

title: Effect of Rosin Resin on the Properties of Natural Rubber/Polyester Layered Fibers
abstract: With the development of rubber technology the requirements for rubber products are becoming more and more strict. Enhancing the interfacial bonding strength between vulcanized natural rubber (NR) and polyester fibers (PEF) has become our research goal. In the research described here the effect of rosin resin (RR) on the properties of NR/PEF was studied. Dynamic experiments were conducted within the strain range from 1 to 100% using a rubber process analyzer (RPA) The adhesive properties of the RR in the NR matrices with the PEF were further studied by the peel test, which indicated an enhancement of the bonding effect in the vulcanized NR PEF composites. The failure modes of the mixtures following various aging conditions were studied by scanning electron microscopy (SEM) When 3phr of RR were added to the NR/PEF composite, the interfacial bonding strength between the rubber and fiber had the best value compare to samples with 0, 1, 2, 4 and 5phr. Our results indicated that RR used as a tackifier added to NR prior to vulcanization improved the bonding between vulcanized NR and the PEF.

title: Morphology, rheology and curing of (ethylene propylene elastomer/hydrogenate acrylonitrile butadiene rubber) blends reinforced by POSS and organoclay
abstract: Nanocomposites based on polyhedral silsesquioxanes POSS and modified montmorillonite MT reinforced ethylene propylene elastomer/hydrogenated butadiene acrylonitrile rubber blends (EPR/HNBR) are reported. The effect of the methacryloisobutyl MIB POSS and octavinyl OV POSS on the curing characteristics, viscoelastic properties, relaxation behavior and morphology of EPR/HNBR blends was determined. The rheometric characteristics, the viscosity of molded rubber blends and kinetic parameters of curing were determined using a RPA rheometer, in which the process of crosslinked network formation was monitored at various temperatures. The obtained results demonstrated a correlation between the calculated activation energies of crosslinking Ea and the viscoelastic properties of POSS functionalized EPR/HNBR composites, which can be particularly seen in OV POSS functionalized EPR/HNBR sample. The increase in EPR glass transition temperature Tg confirmed the formation of OV POSS crosslinks between phases of both rubbers. A relatively more homogeneous morphology, which was investigated by SEM, confirmed the influence of OV POSS on the miscibility of both rubbers.

title: Viscoelastic Behavior, Curing and Reinforcement Mechanism of Various Silica and POSS Filled Methyl Vinyl Polysiloxane MVQ Rubber
abstract: The role of Aerosil silicas, A90, R812, R812s on the complex dynamic viscosity e* of methyl vinyl polysiloxane MVQ at processing temperature 80degC was analyzed based on experiments with a torsional rheometer Rubber Process Analyzer RPA. The influence of surface area and surface activity on the Payne's effect was determined by oscillating rheometer Ares G2. The decrease in complex modulus G* by increasing strain for silicas R812, R812s was mostly due to the breaking down of filler filler networking, the modification of surface led to better processability resulting in the increase of tensile strength TS, from 0.42 MPa unfilled silicone to 9.31 MPa MVQ containing R812. Higher surface activity of silica A90 caused a decrease in filler networking due to a better filler polymer interactions, which resulted in the increase of the percentage of non covalent crosslinks determined for samples treated with ammonia. The decrease of static water contact angle th of silicone rubber after incorporation of A90 was observed. Influence of allylisobutylPOSS on curing, crosslink density, static and dynamic behavior of silicone rubber was considered.

title: Interactions Between an Ionic Liquid and Silica, Silica and Silica, and Rubber and Silica and Their Effects on the Properties of Styrene Butadiene Rubber Composites
abstract: An investigation of the effect of an ionic liquid, 1 butyl 3 methylimidazolium tetrafluoroborate (BMI) on the properties of silica reinforced styrene butadiene rubber (SBR) aimed to correlate the interactions between the ionic liquid and silica, silica and silica, and silica and rubber with the macro properties and microstructure of SBR and SBR/silica vulcanizates is described. The interaction between the ionic liquid and silica was characterized by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) the interaction between silica and silica was characterized by a rubber processing analyzer (RPA) and the interaction between rubber and silica was characterized by the bound rubber content. The FTIR analysis revealed that BMI can react with the hydroxyl groups on the surface of silica, improving the compatibility between the rubber and silica. The RPA and bound rubber testing indicated that the interactions between silica and silica particles were weakened and the interaction between silica and rubber increased with the incorporation of BMI into the SBR rubber. The bound rubber content showed a maximum with a BMI content of 3 phr. At the same time, the dispersion of silica in SBR was improved with the incorporation of BMI. With the increase of BMI content, the curing rate was greatly improved and the crosslink density increased. BMI also increased the tensile strength and abrasion resistance of the SBR vulcanizates. Most important, the BMI significantly improved the dynamic properties of the rubber composites, especially the wet skid resistance and rolling resistance. However, excessive BMI (beyond 3 phr) acted as a plasticizer and was detrimental to the mechanical properties, resulting in a decrease of tensile strength and abrasion resistance.

title: Investigation of Silane Coupling Agents on the Filler Filler and Filler Rubber Interaction and Mechanical Properties of EVM/ATH Composites
abstract: Ethylene vinyl acetate copolymer (EVM)/aluminium trihydrate (ATH) composites were prepared. Vinyl trimethoxysilane (VTMO) triethoxyvinylsilane (VTEO) ethyltrimethoxysilane (ETMO) amino propyl trimethoxysilane (AMMO) four kinds of silanes were used in this research. The effects of silane amount and different kinds of silane on the dispersion and adhesion of the ATH in EVM composites were characterized through RPA, electron microscopy, bound rubber. It was found that the addition of VTMO/AMMO/VTEO led to a dramatic increase in Payne effect and tensile property of the composites. Filler dispersion increased with silane adding, and the interaction of ATH and EVM was found in silane treated composites, in which silane had effective functional groups.

title: The different reinforcing behavior between siliceous earth nanoparticles and silica on natural rubber
abstract: The reinforcing behaviors of siliceous earth (SE) nanoparticles and silica on natural rubber (NR) were compared. SE employed in this work was formed by volcanic eruptions 100 million years ago and mainly consists of SiO2 ~80% Al2O3 ~14% and K2O ~4% and is composed of low quartz and illite in crystal structure and with a special flaky and laminated morphology. The effects of SE slurry with different filler loading of 30, 40, 50 per hundred parts of rubber (phr) and 40 phr silica(S 40) were investigated. Mechanical properties were measured, and the results show that 300% modulus, elongation at break, tensile, and tear strength of SE/NR are all higher than those of S 40. Combination results of tensile properties and rubber process analyzer (RPA) the rubber filler interaction parameter (I) was calculated and the results show the value of I increase slightly with SE loading, while obviously higher than that of S 40. But the results of dynamic mechanical analysis and bound rubber content show that S 40 has obviously lower tan d and higher bound rubber content, which indicate that there exists stronger rubber filler interaction between silica and NR. The seemingly conflicting results imply that the effect of the two fillers on the NR network structure should be different. The special morphology of SE can help them to distribute more evenly in the NR matrix, making it less likely to form particle networks and providing very strong filler rubber interaction, while showing higher average rubber filler interaction and results in better mechanical properties of SE/NR composites.