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In the current study, strain sensors based on two polymer matrixes of polydimethylsiloxane (PDMS) and thermoplastic polyurethane (TPU) and conductive nanomaterials of the silver nanowires (AgNWs) were fabricated. The sensors were arranged with a sandwich like morphology in which AgNWs layer(s) were embedded with polymeric layers of PDMS or TPU. The effect of the polymer matrix type and the number of the conductive layers on sensor properties has been evaluated. Morphology and electromechanical properties of the sensors including electrical resistance (R), sensitivity of the resistance change to strain, linearity of the resistance change with strain and repeatability of the sensor response to cyclic loading were analyzed. The experimental results corroborated that with increasing conductive layers from one to three, the resistance decreased by 53% and 61% in respective PDMS and TPU based sensors. Moreover, the sensitivity decreased by 78% and 77% in PDMS and TPU based sensors, respectively. The calculation of the relative SD (RSD) of the maximum ΔR/R 0 values substantiated that sensors were able to represent a repeatable response to the sequential loading/unloading cycles. The repeatability was decreased with increasing conductive layers from one to two, and then augmented with further increase in conductive layers. With respect to polymer type, the resistance and repeatability of the TPU based sensors was higher than the PDMS counterparts, whereas the sensitivity of the TPU based sensors was lower than the PDMS ones.

Melt viscoelastic behavior and the die swell of Acrylonitrile‐Butadiene‐Styrene (ABS) and ABS/clay nanocomposites varying in organoclay loading were studied. A pronounced low‐frequency nonterminal behavior exhibited in linear viscoelastic experiments along with an apparent yield stress in transient startup flow tests suggested the existence of a network type, because of interconnection of rubber particles in ABS matrix. From the results of linear and nonlinear viscoelastic measurements, it was found that the incorporation of organoclay can lead to the formation of an additional network formed between organoclay tactoids that caused reduced temperature dependency of linear viscoelastic properties of the nanocomposite samples compared with ABS matrix. The swelling behavior of samples was interpreted using the results of stress relaxation experiments after cessation of steady shear flow. The great reduction in the die swell of nanocomposite samples could be explained in terms of great surface area and anisometric nature of organoclay tactoids and/or platelets, which promote energy consumption and less energy to be stored in chains. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers

In this study, the microstructural development and its effect on the thermal conductivity of polyamide6 (PA6)/polypropylene (PP) blends containing boron nitride (BN) and reduced graphene oxide (rGo) as hybrid fillers were investigated. Blend samples were prepared using the masterbatch method to localize BN and rGo in the matrix phase (PA6). Dynamic rheological results were consistent with selective localization of the fillers in PA6 as evidenced by nonterminal behavior (3D network) PP/PA-BN at low frequencies. Compared with the case where the matrix phase (PA6) was only filled with BN particles, thermal conductivity measurements showed that replacing 10% and 15% BN particles with rGo nanoparticles yielded higher thermal conductivity. The hybrid fillers had a synergetic effect on the heat conductive network, forming a more efficient percolating network of BN and rGo in the matrix phase (PA6). A comparison between the BN-filled PA6 blend and the BN-rGo-filled PA6 blend revealed higher thermal conductivity in the PP/PA6-BN-rGo sample with co-continuous morphology than in the PP/PA6-BN sample with matrix-disperse morphology.

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