Studying the roles of nanoclay and blend composition on the improved properties of natural rubber/chloroprene composites

Abstract

Hybrid clay polymer nanocomposites (CPNs) based on blends of natural rubber (NR) and chloroprene rubber (CR) with different compositions (100/0, 95/5, 90/10, 85/15, 80/20), reinforced with various contents of organomodified montmorillonite (OMMT), were prepared by a two-roll mill via a vulcanization process. Curing data of the prepared compounds indicated a reduction in scorch time (t 5 ) and optimum cure time (t 90 ) with increasing the nanoclay content. Mechanical properties of samples were markedly enhanced upon nanoclay inclusion, due to the proper level of interactions established between nanoclay particles and the rubber matrix as it was evidenced by SEM photomicrographs. Results of X-ray diffraction proved the expansion of the interlayer distance, and transmission electron microscopy micrographs further confirmed that the prepared CPN samples exhibit intercalated/partially exfoliated structures. Moreover, the reinforcement effect of OMMT was reflected in the stress-induced crystallization and network structure of the CPNs based on the rubber-elasticity and tube model theories as well as rheological properties. POLYM. COMPOS., 39:1562-1574

Enhancement of thermal, morphological, and mechanical properties of compatibilized based onPA6‐enriched graphene oxide/EPDM‐g‐MA/CR: Graphene oxide andEPDM‐g‐MAcompatibilizer role

“…Also, in this equation, the yield stress calculated by σ 0 = . In addition, n (Shear thinning behavior) is investigated the physical network strength and microstructure 50 and also the increase in GO nanoplatelets concentration indicates a stronger network at lower n value in the nanocomposite. In addition, higher yield stress related to the stronger GO networks and PA6/CR/GO interactions.…”

“…In addition, increasing the concentration of GO due to the Newtonian plateau of shear viscosity to the lower frequencies, leading to an earlier onset of shear thinning. The decreases in the complex modulus as the complex viscosity increase is represents of apparent yield stress, assigned to the formation of GO nanoplatelets networks 50 …”

“…The decreases in the complex modulus as the complex viscosity increase is represents of apparent yield stress, assigned to the formation of GO nanoplatelets networks. 50 The modified Herschel-Bulky model was used to better evaluate the apparent yield stress of nanocomposites:…”

Enhanced compatibility, morphology, rheological and mechanical properties of carboxylated acrylonitrile butadiene rubber/chloroprene rubber/graphene nanocomposites: effect of compatibilizer and graphene content

“…The interfacial adhesion between the graphene nanoplatelets, XNBR-g-GMA compatibilizer and the continuous phase of XNBR/CR can be attributed to the ring opening reaction of epoxide functional groups of the XNBR-g-GMA compatibilizer and carboxyl groups of XNBR. 28,29 Therefore, it can be concluded that the graphene nanoplatelets are effectively dispersed in the continuous phase of XNBR/CR due to the increased torque and viscosity of the nanocomposite blend. However, in nanocomposites containing CR, with increasing graphene, the scorch time decreased, but the optimum curing time increased.…”

“…where, l m is the maximum extension ratio at breaking point. Small upturn, (1/l) up , which can be usually observed in the nanocomposites stress-strain diagrams in large strain deformations, is approximated by eqn (12): 28 1…”