In order to minimize the oxidative degradation of SBR at high temperature, the nano-dispersed clay layers were introduced by using the SBR/clay (100/80) nanocompound to prepare SBR/clay/carbon black (CB) nanocomposites, then the effects of nano-clay on the properties of SBR nanocomposites are investigated. The clay layers and CB are uniformly dispersed in the SBR matrix at nano-scale. The mechanical properties of the SBR/clay/CB nanocomposites mostly decrease with the increase of clay loading, however, with the increase of clay loading, the change rate of the mechanical properties of the nanocomposites decreases and the aging coefficient of the nanocomposites rises, and the length and depth of the cracks of the aged nanocomposites after bending decrease, which means that the clay layers can provide the nanocomposites excellent thermal aging resistance and heat resistance. The experiment of aging with air and without air proved the importance of oxygen during rubber aging process. The FTIR spectra show the generation of oxygen-containing group on the external surface of the nanocomposites during aging. The DSC results indicate the differences between the internal layer and the external layer of the aged nanocomposites. 相似文献
Water‐induced mechanically adaptive rubber nanocomposites were prepared by mixing bacterial cellulose whiskers (BCWs) suspension with styrene‐butadiene rubber (SBR) latex, followed by evaporation method. The structure, morphology, dynamic mechanical properties, water stimuli‐responsive behavior, and biodegradability of SBR/BCWs nanocomposite films were investigated. The results showed that the hydrophilic whiskers had a significant reinforcement effect on the storage modulus of SBR matrix, which originated from the formation of a rigid three‐dimensional filler network within matrix by strong hydrogen bonding between whiskers. The SBR/BCWs nanocomposites showed pronounced water stimuli‐responsive behavior compared with neat SBR. The storage modulus of SBR/BCWs nanocomposite could be decreased by 99.2% after equilibrium water swelling. This remarkable water‐triggered modulus change is attributed to the disentanglement of BCWs network via competitive hydrogen bonding with water. 相似文献
Natural rubber (NR)/rectorite nanocomposite was prepared by co-coagulating NR latex and rectorite aqueous suspension. The transmission electron microscopy (TEM) and X-ray diffraction (XRD) were employed to characterize the microstructure of the nanocomposite. The results showed that the nanocomposite exhibited a higher glass transition temperature, lower tan δ peak value and slightly broader glass transition region compared with pure NR. The gas barrier properties of the NR/rectorite nanocomposites were remarkably improved by the introduction of nanoscale rectorite because of the increased tortuosity of the diffusive path for a penetrant molecule. The nanocomposites have a unique stress-strain behavior due to the reinforcement and the hindrance of rectorite layers to the tensile crystallization of NR. 相似文献
An aqueous slurry of α-ZrP lamellar nanofillers has been modified by amine type surfactants. The influence of the alkylamine chain length and of the cationic exchange rate on the nanofiller d-spacing has been analyzed. The strength of the interactions formed between the intercalating agent and the filler has been studied by Infra Red Spectroscopy (FTIR), Solid-state Nuclear Magnetic Resonance (31P MAS NMR) and Thermogravimetric Analysis (TGA). Different routes allowing to obtain optimized filler properties while minimizing the surfactant weight amount have been proposed from the detailed analysis of the intercalation mechanism. Styrene Butadiene Rubber nanocomposites have been prepared directly from the different slurries of modified α-ZrP. The dispersion of the organophilic α-ZrP in the SBR matrix has been characterized and the mechanical properties of the corresponding nanocomposites have been determined and discussed as a function of the filler modification, of the nanocomposite morphology and of the filler/matrix interfacial properties. 相似文献
Ethylene-co-acrylic acid (EAA) and ethylene-co-methacrylic acid ionomer (EMAZ) copolymers were used as compatibilizers for polyethylene-graphene nanocomposites generated by melt mixing. At 5 wt% content, the EAA compatibilizer enhanced the tensile modulus of PE by 40 % and shear modulus by >300 % (1 rad/s) due to efficient dispersion of graphene platelets which helped in effective stress transfer. These also resulted in enhanced thermal stability for PE-EAA-G nanocomposite as compared to nanocomposite with EMAZ. The properties of the nanocomposites were significantly better than the conventional nanocomposites based on layered silicate materials. Mapping of the component distribution in the nanocomposites was demonstrated by using hyperspectral imaging. The nanocomposite with EAA exhibited higher extent of spectral signal mixing due to better mixing of filler and compatibilizer in PE matrix. On the other hand, nanocomposite with EMAZ had no spectral mixing as the components did not mix optimally with each other. The DSC thermogram for this nanocomposite also exhibited a small shoulder at low temperature probably due to immiscibility of the compatibilizer with the matrix polymer. The hyperspectral imaging and mapping was thus demonstrated to be a useful method for determination of component distribution in complex nanocomposite systems. 相似文献
As a widely used reinforcing filler of rubber, carbon black(CB) often enhances the nonlinear Payne effect and its mechanism still remains controversial. We adopt simultaneous measurement of rheological and electrical behaviors for styrene-butadiene rubber(SBR)/CB compounds and CB gel(CBG) during large deformation/recovery to investigate the contribution of conductive CB network evolution to the Payne effect of the compounds. In the highly filled compounds, the frequency dependence of their strain softening behavior is much more remarkable than that of their CB network breakdown during loading, while during unloading the unrecoverable filler network hardly affects the complete recovery of modulus, both revealing that their Payne effect should be dominated by the disentanglement of SBR matrix. Furthermore,the bound rubber adjacent to CB particles can accelerate the reconstruction of continuous CB network and improve the reversibility of Payne effect. This may provide new insights into the effect of filler network, bound rubber, and free rubber on the Payne effect of CB filled SBR compounds. 相似文献
A series of blue dye molecules, Evans blue (EB), Chicago sky blue (CB), Niagara blue (NB) were incorporated by direct co-precipitation within the galleries of negatively charge layered double hydroxide (LDH). The materials of cation composition Zn/Al = 2 lead to well-defined organic inorganic assemblies. The molecular arrangement of the interleaved dye molecule is proposed by 1D electronic density projection along the stacking direction for the hydrothermally treated samples with alternatively a highly inclined orientation of EB and CB and a parallel-bilayer arrangement for NB. Blue coloured LDH assemblies were subsequently dispersed into polystyrene (PS). It was found that the hybrid fillers do not interfere in the radical polymerization of styrene, giving rise to similar molecular weight and polydispersity than filler free PS, while higher glass transition temperatures were obtained for the nanocomposites. This was consistent with the rheological behaviour with the observation for LDH/NB filler based nanocomposite of shear thinning exponent different from zero, underlining frictional interaction between filler and PS chain. The absorption maximum slightly blue-shifted for the hybrid filler in comparison to the corresponding organic dye was found unmodified for the PS nanocomposite, thus giving rise to blue coloured plastic films, reminiscent somehow of the blue Maya effect. 相似文献
Three nylon-6/unmodified clay/rubber nanocomposites with high toughness, high stiffness, high heat resistance and reduced flammability were studied in this paper, on basis of three compound powders of ultra-fine full-vulcanized powdered rubber (UFPR)/montmorillonite (UFPRM). It was found that all of the three UFPRs used in the study can help the silicate layers without organic treatment to be exfoliated in the nylon-6 matrix, despite some differences in compatibilities between them and nylon-6. Accordingly, the clay in different UFPRMs at the same loading content can lead to a similar improvement in stiffness and heat resistance of nanocomposites. In other words, UFPRs having different compatibilities with nylon-6 do not affect the stiffness and heat resistance of nanocomposites largely. However, the nylon-6 nanocomposites, modified with different UFPRMs, show different superior properties. Butadiene styrene vinyl-pyridine UFPRM (VP-UFPRM) is more effective in improving toughness of nylon-6. Nylon-6/silicone UFPRM (nylon-6/S-UFPRM) nanocomposite exhibits more reduced flammability, good flowability and high thermal stability. As for nylon-6/acrylate UFPRM (nylon-6/A-UFPRM) nanocomposite, it shows high toughness and thermal stability. Furthermore, the mechanism of unmodified clay exfoliation during the melt compounding and the effect of different UFPRs on the properties of the nylon-6/UFPRM nanocomposites are also discussed. 相似文献
The effect of polymer-filler interaction on interphase dynamics between filler particles in elastomer nanocomposites and the mechanisms of rubber reinforcement by carbon black (CB) are investigated with different techniques. To determine how polymer-filler interface influences the properties of the system, CB black was modified with the ionic liquid (IL) 1-allyl-3-methylimidazolium chloride (AMIC) and mixed with different, more or less, polar elastomers. For typical diene-elastomers (EPDM, SBR), this modification leads to a decreased polymer-filler coupling strength due to the coverage of active sites at the CB surface by AMIC. This is demonstrated by evaluating the energy site distribution from static gas adsorption isotherms with the polymer analogues gas 1-Butene. However, an improvement of polymer filler coupling was determined in the case of saturated, polar rubbers (HNBR) due to attractive dipolar interactions between the polar units of the polymer and the strongly adsorbed IL at the CB surface. The different couplings affect the polymer-filler interphase dynamics between filler particles, which determines the properties of the filler network and filler-filler bonds. To describe the effect of CB surface modification quantitatively, the Dynamic Flocculation Model (DFM) has been used to calculate polymer- and filler-specific material parameters from cyclic stress-strain measurements. The fitted data deliver a coherent picture of filler-filler- and polymer-filler couplings showing a characteristic dependence on rubber polarity. A confirmation of the effect of surface modification on the strength of filler-filler bonds is obtained by nonequilibrium molecular dynamics (MD) simulations of bond rupture under tension. They also provide indications for a glassy-like behavior of strongly confined polymer layers between attractive walls. 相似文献
The effect of Alkanolamide (ALK) loading on properties on three different types of carbon black (CB)-filled rubbers (SMR-L, ENR-25, and SBR) was investigated. The ALK loadings were 1.0, 3.0, 5.0 and 7.0 phr. It was found that ALK gave cure enhancement, better filler dispersion and greater rubber–filler interaction. ALK also enhanced modulus, hardness, resilience and tensile strength, especially up to 5.0 phr of loading in SMR-L and SBR compounds, and at 1.0 phr in ENR-25 compound. Scanning electron microscopy (SEM) proved that each optimum ALK loading exhibited the greatest matrix tearing line and surface roughness due to better rubber - filler interaction. 相似文献
Summary: The size and concentration of free‐volume holes of two kinds of montmorillonite (MMT)/styrene‐butadiene rubber (SBR) nanocomposites were investigated by positron annihilation lifetime spectroscopy (PALS). Strong interfacial interaction caused an apparent reduction of the free‐volume fraction of rubber probably by depressing the formation of free‐volume holes in the interfacial region. Interfacial interaction in MMT/SBR nanocomposites was weaker than that in SBR filled with carbon black.
Dependence of normalized o‐Ps intensity of four kinds of composites on filler volume fraction. 相似文献