scholarly journals Monitoring of Curing and Cyclic Thermoresistive Response Using Monofilament Carbon Nanotube Yarn Silicone Composites

2021 ◽  
Vol 7 (3) ◽  
pp. 60
Author(s):  
Tannaz Tayyarian ◽  
Omar Rodríguez-Uicab ◽  
Jandro L. Abot
Keyword(s):  
Carbon Nanotube ◽  
Heating Rate ◽  
Electrical Resistance ◽  
Room Temperature ◽  
Electrical Response ◽  
Negative Temperature ◽  
Curing Kinetics ◽  
Curing Process ◽  
Resistance Change ◽  
Electrical Resistance Change

The curing process and thermoresistive response of a single carbon nanotube yarn (CNTY) embedded in a room temperature vulcanizing (RTV) silicone forming a CNTY monofilament composite were investigated toward potential applications in integrated curing monitoring and temperature sensing. Two RTV silicones of different crosslinking mechanisms, SR1 and SR2 (tin- and platinum-cured, respectively), were used to investigate their curing kinetics using the electrical response of the CNTY. It is shown that the relative electrical resistance change of CNTY/SR1 and CNTY/SR2 monofilament composites increased by 3.8% and 3.3%, respectively, after completion of the curing process. The thermoresistive characterization of the CNTY monofilament composites was conducted during heating–cooling ramps ranging from room temperature (RT~25 °C) to 100 °C. The thermoresistive response was nearly linear with a negative temperature coefficient of resistance (TCR) at heating and cooling sections for both CNTY/SR1 and CNTY/SR2 monofilament composites. The average TCR value was −8.36 × 10−4 °C−1 for CNTY/SR1 and −7.26 × 10−4 °C−1 for CNTY/SR2. Both monofilament composites showed a negligible negative residual relative electrical resistance change with average values of ~−0.11% for CNTY/SR1 and ~−0.16% for CNTY/SR2 after each cycle. The hysteresis amounted to ~21.85% in CNTY/SR1 and ~29.80% in CNTY/SR2 after each cycle. In addition, the effect of heating rate on the thermoresistive sensitivity of CNTY monofilament composites was investigated and it was shown that it reduces as the heating rate increases.

CYCLIC THERMORESISTIVITY OF CARBON NANOTUBE YARN/SILICONE RUBBER MATRIX MONOFILAMENT COMPOSITES

2021 ◽  
Author(s):  
TANNAZ TAYYARIAN ◽  
OMAR RODRIGUEZ-UICAB ◽  
TANJEE AFREEN ◽  
JANDRO L. ABOT
Keyword(s):  
Carbon Nanotube ◽  
Electrical Resistance ◽  
Room Temperature ◽  
Electrical Response ◽  
Negative Temperature ◽  
Curing Kinetics ◽  
Rubber Matrix ◽  
Continuous Heating ◽  
Average Value ◽  
Heating And Cooling

Thermoresistive characterization of CNTY monofilament composites was investigated by using the electrical response of a single carbon nanotube yarn (CNTY) embedded in a silicone polymer forming monofilament composites. Two room temperature vulcanizing (RTV) silicone rubbers with different polymerization mechanisms (OOMOO and Ecoflex) were used as the polymeric matrices. Continuous heating-cooling thermal cycling ranging from room temperature (RT~25 °C) to 80 °C was performed in order to determine the thermoresistive sensitivity, hysteresis and residual fractional change in electrical resistance after each cycle. The thermoresistive response was nearly linear, with negative temperature coefficient of resistance at the heating and cooling zones for CNTY/ OOMOO and CNTY/Ecoflex specimens. The average value of this coefficient at the heating and cooling sections was - 6.65×10-4 °C-1 for CNTY/OOMOO and -7.35×10-4 °C-1 for CNTY/Ecoflex. Both monofilament composites showed a negligible negative residual electrical resistance with an average value of ~ -0.08% for CNTY/OOMOO and ~ -0.20% for CNTY/Ecoflex after each cycle. The hysteresis yielded ~19.3% for CNTY/OOMOO and ~29.2% in CNTY/Ecoflex after each cycle. Therefore, the curing kinetics and viscosity play a paramount role in the electrical response of the CNTY immersed into these rubbery matrices.

EFFECT OF CURING TEMPERATURE OF EPOXY RESIN ON THE ELECTRICAL RESPONSE OF CARBON NANOTUBE YARN MONOFILAMENT COMPOSITES

2021 ◽  
Author(s):  
OMAR RODRIGUEZ-UICAB ◽  
JANDRO L. ABOT ◽  
FRANCIS AVILÉS
Keyword(s):  
Carbon Nanotube ◽  
Epoxy Resin ◽  
Electrical Resistance ◽  
Epoxy Resins ◽  
Room Temperature ◽  
Negative Temperature Coefficient ◽  
Electrical Response ◽  
Negative Temperature ◽  
Curing Temperature ◽  
Temperature Coefficient Of Resistance

The cyclic thermoresistive response of individual carbon nanotube yarns (CNTYs) embedded into epoxy resins is investigated. The influence of the temperature at which the epoxy resin cures on the thermoresistive response is investigated by using two epoxy resins, one that cures at room temperature and the other one that cures at 130 °C. Heating-cooling cycles ranging from room temperature (RT, 25 °C) to 80 °C, incremental cycles (RT to 40 °C, RT to 60 °C and RT to 80 °C) and incremental heating-dwell cycles are applied to monofilament composites, while their electrical resistance is simultaneously recorded. The monofilament composites showed a negative temperature coefficient of resistance during the heating-cooling cycles of -7.07x10-4 °C-1 for specimens cured at high temperature, and -5.93x10-4 °C-1 for specimens cured at room temperature. The hysteresis after the different heating-cooling cycles was slightly smaller for specimens cured at 130 °C, in comparison to specimens cured at room temperature. Several factors including the intrinsic thermoresistivity of CNTY, level of infiltration and the effect of curing temperature may explain the thermoresistive sensitivity of the monofilament composites.

scholarly journals Electrical Resistance Sensing of Epoxy Curing Using an Embedded Carbon Nanotube Yarn

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3230 ◽  
Author(s):  
Omar Rodríguez-Uicab ◽  
Jandro L. Abot ◽  
Francis Avilés
Keyword(s):  
Carbon Nanotube ◽  
Epoxy Resin ◽  
Electrical Resistance ◽  
Electrical Response ◽  
Curing Kinetics ◽  
Curing Temperature ◽  
Polymerization Process ◽  
Curing Agent ◽  
Resin Curing ◽  
Over Time

Curing effects were investigated by using the electrical response of a single carbon nanotube yarn (CNTY) embedded in an epoxy resin during the polymerization process. Two epoxy resins of different viscosities and curing temperatures were investigated, varying also the concentration of the curing agent. It is shown that the kinetics of resin curing can be followed by using the electrical response of an individual CNTY embedded in the resin. The electrical resistance of an embedded CNTY increased (~9%) after resin curing for an epoxy resin cured at 130 °C with viscosity of ~59 cP at the pouring/curing temperature (“Epon 862”), while it decreased (~ −9%) for a different epoxy cured at 60 °C, whose viscosity is about double at the corresponding curing temperature. Lowering the curing temperature from 60 °C to room temperature caused slower and smoother changes of electrical resistance over time and smaller (positive) residual resistance. Increasing the concentration of the curing agent caused a faster curing kinetics and, consequently, more abrupt changes of electrical resistance over time, with negative residual electrical resistance. Therefore, the resin viscosity and curing kinetics play a paramount role in the CNTY wicking, wetting and resin infiltration processes, which ultimately govern the electrical response of the CNTY immersed into epoxy.

Electrical Failure and Damage Analysis of Multi-Layer Metal Films on Flexible Substrate during Cyclic Bending Deformation

2011 ◽  
Author(s):  
Byoung-Joon Kim ◽  
Hae-A-Seul Shin ◽  
In-Suk Choi ◽  
Young-Chang Joo
Keyword(s):  
Fatigue Resistance ◽  
Electrical Resistance ◽  
Metal Film ◽  
Flexible Substrate ◽  
Resistance Change ◽  
Cyclic Bending ◽  
Capping Layer ◽  
Bending Strain ◽  
Cu Film ◽  
Electrical Resistance Change

Abstract The electrical resistance Cu film on flexible substrate was investigated in cyclic bending deformation. The electrical resistance of 1 µm thick Cu film on flexible substrate increased up to 120 % after 500,000 cycles in 1.1 % tensile bending strain. Crack and extrusion were observed due to the fatigue damage of metal film. Low bending strain did not cause any damage on metal film but higher bending strain resulted in severe electrical and mechanical damage. Thinner film showed higher fatigue resistance because of the better mechanical property of thin film. Cu film with NiCr under-layer showed poorer fatigue resistance in tensile bending mode. Ni capping layer did not improve the fatigue resistance of Cu film, but Al capping layer suppressed crack formation and lowered electrical resistance change. The NiCr under layer, Ni capping layer, and Al capping layer effect on electrical resistance change of Cu film was compared with Cu only sample.

A highly-deformable piezoresistive film composed of a network of carbon blacks and highly oriented lamellae of high-density polyethylene

RSC Advances ◽  
2015 ◽  
Vol 5 (39) ◽  
pp. 31074-31080 ◽  
Author(s):  
Shaodi Zheng ◽  
Jie Deng ◽  
Luqiong Yang ◽  
Danqi Ren ◽  
Wei Yang ◽  
...  
Keyword(s):  
Electrical Resistance ◽  
High Density Polyethylene ◽  
High Density ◽  
Resistance Change ◽  
Carbon Blacks ◽  
Electrical Resistance Change

The electrical resistance change of highly extensible films consisting of a network of carbon blacks in high-density polyethylene, with different regularity of stacked lamellae, is investigated.

Signal conditioning circuit for gel strain sensors

2021 ◽  
Author(s):  
Ismael Payo ◽  
J. L. Polo ◽  
Blanca Lopez ◽  
Diana Serrano ◽  
Antonio M. Rodríguez ◽  
...  
Keyword(s):  
Electrical Resistance ◽  
Pressure Sensors ◽  
Strain Sensors ◽  
Resistance Force ◽  
Electrode Impedance ◽  
Signal Conditioning ◽  
Resistance Change ◽  
Signal Conditioning Circuit ◽  
Conditioning Circuit ◽  
Electrical Resistance Change

Abstract Conductive Hydrogels are soft materials which have been used by some researchers as resistive strain sensors in the last years. The electrical resistance change, when the sensor is stretched or compressed, is usually measured by the two-electrode method. This method is not always suitable to measure the electrical resistance of polymers-based materials, like hydrogels, because it could be highly influenced by the electrode/sample interface, as explained in this study. For this reason, a signal conditioning circuit, based on four-electrode impedance measurements, is proposed to measure the electrical resistance change when the gel is stretched or compressed. Experimental results show that the tested gels can be used as resistance force/pressure sensors with a quite linear behaviour.

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