Search

The incompatible thermoplastic poly lactic acid/carboxylated acrylonitrile butadiene rubber (PLA/XNBR) was prepared, and the effect of graphene oxide (GO) as a reinforcement and glycidyl methacrylate (GMA)-grafted XNBR (XNBR-g-GMA) as a compatibilizer on the properties of PLA/XNBR blend was investigated in this research. The microstructure, mechanical behavior, thermal, rheology, and dynamic mechanical properties of PLA/XNBR composites were investigated by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), tensile test, and dynamic mechanical thermal analysis (DMTA). The incorporation of XNBR-g-GMA improved the compatibility of the PLA/XNBR blend phases, as confirmed by microstructure and DMTA analysis. The results of the mechanical properties showed that with an increase in GO content in the PLA/XNBR/XNBR-g-GMA matrix, there was a significant improvement in tensile strength, Young's modulus, hardness, and impact strength. In order to validate the experimental mechanical and rheological results, various theoretical models were applied and a good agreement was observed between the theoretical and experimental data. [ABSTRACT FROM AUTHOR]

In this research, nanocomposites based on carboxylated nitrile rubber (XNBR)/natural rubber (NR) with different concentrations of graphene oxide (GO) were prepared by melt mixing method. The role of XNBR-grafted maleic anhydride (XNBR-g-GMA) as a compatibilizer and the effect of GO content on the morphological, mechanical, rheological, and vulcanization properties were evaluated. It was observed that with increasing the concentration of GO, the scorch and vulcanization time decreased, while the torque of the samples increased. Morphological studies illustrated that by raising the concentration of GO in the presence of a compatibilizer, the fracture surface of nanocomposites became rougher and the average size of dispersed phase decreased. In addition, the presence of XNBR-g-GMA compatibilizer improved the uniform dispersion of GO within the XNBR/XNBR-g-GMA/NR matrix. The mechanical properties of nanocomposites showed the best results for XNBR/NR with a ratio of 75/25. Theoretical studies on the mechanical and rheological properties of nanocomposites performed by Mori-Tanaka and Carreau-Yasuda models and illustrated a good agreement with experimental data. [ABSTRACT FROM AUTHOR]

The current research aimed to investigate the different aspects of novel nanocomposites based on carboxylated acrylonitrile butadiene rubber (XNBR), carboxylated styrene butadiene rubber (XSBR), graphene oxide (GO), and glycidyl methacrylate-grafted XNBR compatibilizer (XNBR-g-GMAC) blend. For this purpose, the novel nanocomposites of GO-XNBR-g-GMAC/XNBR/XSBR with different XNBR, XSBR, and GO composition and with and without XNBR-g-GMAC were synthesized. The related characteristics including curing properties, swelling behavior, morphological, electrical and mechanical characteristics were studied through rheometry, swelling test, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) observation, electrical resistivity, mechanical test, dynamic mechanical thermal analysis (DMTA), etc. Results of rheometric tests revealed that the addition of XNBR-g-GMAC and increasing GO content reduces the scorch time (t5) and optimum cure time (t90) and increases the crosslink density (CLD). So that the addition of 5 phr of compatibilizer and 1 phr of GO to the XNBR75/XSBR25 blend reduced the t5 and t90 by 29% and 34%, respectively. TEM micrograph confirms the GO dispersion in rubber matrix and SEM observation shows that incorporation of XNBR-g-GMAC and GO reduces dispersed-phase droplet size due to the improved compatibility of XNBR and XSBR. According to the DMTA result, all the samples except XNBR/XSBR (without XNBR-g-GMAC) show one glass transition temperature (Tg) which means XNBR-g-GMAC successfully enhanced the compatibility of XNBR/XSBR. The mechanical properties of samples showed that by the increase of GO concentration tensile strength, elongation at break, modulus, fatigue life, and hardness increased. Testing surface temperature changes in constant voltage (75 V) showed that the addition of 0.3 phr GO showed the best result and the further increase of GO up to the value of 1 phr revealed the opposite result and caused a decrease of about 54%. The results of practical tests also confirm the theories. [ABSTRACT FROM AUTHOR]

In this study, nanocomposites based on polyamide 6/carboxylated acrylonitrile butadiene rubber (PA6/XNBR) reinforced by the clay montmorillonite (OMMT) (Cloisite 20A and Cloisite 30B) were prepared by melt mixing. Glycidyl methacrylate‐grafted XNBR (XNBR‐g‐GMA) compatibilizer was used for immiscible blends of PA6/XNBR. The results illustrated that OMMT wanted to be selectively present in the more hydrophilic PA6 phase. Also, by adding the XNBR‐g‐GMA compatibilizer and increasing OMMT content, tensile strength, rheological and dynamic mechanical properties of the nanocomposites improved. According to transmission electron microscopy (TEM) images, a few layers of OMMT (Cloisite 20A) in the XNBR‐g‐GMA compatibilizer phase was observed. The results of X‐ray diffractometry and TEM analyses demonstrated that the formation of intercalated or exfoliated structures for both types of OMMT nanocomposites. In end of all analysis was found PA6/XNBR reinforced by the Cloisite 30B could be substantially improved by adding XNBR‐g‐GMA as a compatibilizer when compared to those reinforced by Cloisite 20A. [ABSTRACT FROM AUTHOR]

Nonlinear elastoplastic behavior of the nanocomposites based on the styrene–acrylonitrile/carboxylated acrylonitrile butadiene rubber (SAN/XNBR) blend was investigated using experimental and theoretical analysis. Graphene, graphene oxide nanoparticles, and glycidyl methacrylate‐grafted‐XNBR (XNBR‐g‐GMA) as a compatibilizer were incorporated in the SAN/XNBR blends. In this regard, the focus of this study is on modeling of the stress–strain behavior of these nanocomposites, considering the effect of the interfacial interactions made by compatibilizer. For this purpose, field emission scanning electron microscopy (FESEM) and transmission electron microscope (TEM) techniques were used to investigate the relationship between microstructure and mechanical properties of nanocomposites. In addition, FESEM and TEM images showed that the presence of a compatibilizer could influence the dispersion and localization of the nanoparticles. According to the tensile test results, the presence of the compatibilizer increased the mechanical properties of the nanocomposites, specifically elongation at break. Considering the nanocomposite containing compatibilizer and graphene oxide, the elongation at break increased about 570% compared with the nanocomposite without compatibilizer. Better dispersion of graphene oxide and the creation of chemical interaction among components in the presence of the XNBR‐g‐GMA compatibilizer could be the reasons for these improvements, as confirmed by TEM. The usage of the Bergstrom–Boyce model for analyzing the nonlinear elastoplastic behavior of the nanocomposites illustrated proper conformity with the experimental data in the elastic region. However, there are some deviations in the viscoplastic region, particularly close to the breaking elongation region. [ABSTRACT FROM AUTHOR]