Effect of strain rate on tensile properties of polyurethane/(multiwalled carbon nanotube) nanocomposite

Abstract

In this research, polyurethane (PU)/(carbon nanotube) (CNT) samples, with two different contents of multiwalled carbon nanotubes (MWCNTs; i.e., 0.5 and 1.0 wt%) were fabricated through a solution casting method. To investigate the effect of strain rate on tensile properties, tensile tests were done on standard samples at constant temperature and different strain rates (2 3 10 25 to 2 3 10 22 s 21 ). Eyring's model was performed to clarify the role of both strain rate and CNTs content on activation volume and activation enthalpy of PU. To elucidate the role of strain rate and CNTs content on fracture behavior of PU, fracture surfaces of some samples were also investigated by scanning electron microscopy. The results of tensile tests show the intense effect of strain rate on tensile properties of PU/MWCNTs nanocomposites. Also, it was proved that the dependency of tensile properties of PU nanocomposites on strain rate decreases as CNTs content increases. The microscopic observations of the samples also demonstrate that increasing the strain rate changes the behavior of the fracture surface to less a ductile fracture, and increasing CNTs content causes much surface roughness. Finally, by investigation of the activation enthalpies, it is confirmed that much higher enthalpy is needed to fracture the samples with increased MWCNTs content, as the activation enthalpy changes from 45 for neat PU to 131 kJ/mol for PU/(1% MWCNTs) samples. J. VINYL ADDIT. TECHNOL.,

Experimental and modeling investigation of shape memory behavior of polyurethane/carbon nanotube nanocomposite

“…This could be attributed to the strong interfacial bonding between polar groups (COOH) of MWCNTs surface and amide group (CONH) of PU molecular chains, which appears as hydrogen bonding. The existence of these groups and interfacial bonding between PU and CNTs is also presented in our previous work by the investigation of FTIR spectra of nanocomposite samples 13. Mechanical properties of nanocomposite materials are also dependent on the presence of defects which cause to initiate fracture.…”

“…It is also due to the heterogeneous chemical and physical characteristics of PUs and also the ability to add different functional groups to polymer network as well as the fabrication of various copolymers. Depending on the structure, PUs can change from a hard rigid thermosetting to softer elastomeric materials …”

“…Depending on the structure, PUs can change from a hard rigid thermosetting to softer elastomeric materials. 13 SMPs have entered different industrial applications including intelligent packaging, aerospace, sensors and actuators, smart fabrics, biomedical devices, textiles, energy, electronic and civil engineering, and household products. 10,14 One of the biomedical applications of SMPU is a microactuator used to remove blood vessel clots.…”

Effect of strain rate on the fracture behaviour of epoxy–graphene nanocomposite

“…Therefore, a deep understanding about the effect of strain rate on polymer properties is crucial in the design and safe in service performance of polymeric structural components [1]. Almost all different mechanical properties of polymers, such as elastic modulus, yield and strength are sensitive to the rate of loading and deformation [2].…”

“…Jacob et al [13] have provided a nice review on works conducted to investigate the strain rate dependency of mechanical properties of polymer composite materials. Moghim and Zebarjad [2] investigated the effect of carbon nanotubes (CNTs) on the mechanical properties of polyurethane-based nanocomposites. They observed a positive intense effect of strain rate on tensile properties of polyurethane/multiwalled carbon nanotubes (PU/MWCNTs) nanocomposites and also proved that this dependency decreased as CNTs content increased.…”