Separating Curing and Temperature Effects on the Temperature Coefficient of Resistance for a Single-Walled Carbon Nanotube Nanocomposite
The temperature coefficient of resistance (<i>TCR</i>) determines the electrical performance of materials in electronics. For a carbon nanotube (CNT) nanocomposite, change of resistivity with temperature depends on changes in CNT intrinsic conductivity, tunnelling thresholds and distance...
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MDPI AG
2023-01-01
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| Series: | Polymers |
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| Online Access: | https://www.mdpi.com/2073-4360/15/2/433 |
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| author | Milad Jafarypouria Biltu Mahato Sergey G. Abaimov |
| author_facet | Milad Jafarypouria Biltu Mahato Sergey G. Abaimov |
| author_sort | Milad Jafarypouria |
| collection | DOAJ |
| description | The temperature coefficient of resistance (<i>TCR</i>) determines the electrical performance of materials in electronics. For a carbon nanotube (CNT) nanocomposite, change of resistivity with temperature depends on changes in CNT intrinsic conductivity, tunnelling thresholds and distances, matrix’ coefficient of thermal expansion, and other factors. In our study, we add one more influencing factor–the degree of cure. Complexities of the curing process cause difficulties to predict, or even measure, the curing state of the polymer matrix while uncertainty in the degree of cure influences <i>TCR</i> measurements leading to biased values. Here we study the influence of the cure state on the <i>TCR</i> of a single-walled CNT/epoxy polymer nanocomposite. For the given degree of cure, <i>TCR</i> measurements are conducted in the temperature range 25–100 °C, followed by the next 24 h of post-curing and a new cycle of measurements, 8 cycles in total. We find that contrary to industry practice to expect a high degree of cure after 3 h at 130 °C, the curing process is far from reaching the steady state of the material and continues at least for the next 72 h at 120 °C, as we observe by changes in the material electrical resistivity. If <i>TCR</i> measurements are conducted in this period, we find them significantly influenced by the post-curing process continuing in parallel, leading in particular to non-monotonic temperature dependence and the appearance of negative values. The unbiased <i>TCR</i> values we observe only when the material reaches the steady state are no longer influenced by the heat input. The dependence becomes steady, monotonically increasing from near zero value at room temperature to 0.001 1/°C at 100 °C. |
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| id | doaj.art-4b60117e88514c03bc289d15d4e167f7 |
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| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-03-09T11:23:15Z |
| publishDate | 2023-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Polymers |
| spelling | doaj.art-4b60117e88514c03bc289d15d4e167f72023-12-01T00:09:59ZengMDPI AGPolymers2073-43602023-01-0115243310.3390/polym15020433Separating Curing and Temperature Effects on the Temperature Coefficient of Resistance for a Single-Walled Carbon Nanotube NanocompositeMilad Jafarypouria0Biltu Mahato1Sergey G. Abaimov2Center for Petroleum Science and Engineering, Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30 bld. 1, Moscow 121205, RussiaCenter for Petroleum Science and Engineering, Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30 bld. 1, Moscow 121205, RussiaCenter for Petroleum Science and Engineering, Skolkovo Institute of Science and Technology, Bolshoy Boulevard 30 bld. 1, Moscow 121205, RussiaThe temperature coefficient of resistance (<i>TCR</i>) determines the electrical performance of materials in electronics. For a carbon nanotube (CNT) nanocomposite, change of resistivity with temperature depends on changes in CNT intrinsic conductivity, tunnelling thresholds and distances, matrix’ coefficient of thermal expansion, and other factors. In our study, we add one more influencing factor–the degree of cure. Complexities of the curing process cause difficulties to predict, or even measure, the curing state of the polymer matrix while uncertainty in the degree of cure influences <i>TCR</i> measurements leading to biased values. Here we study the influence of the cure state on the <i>TCR</i> of a single-walled CNT/epoxy polymer nanocomposite. For the given degree of cure, <i>TCR</i> measurements are conducted in the temperature range 25–100 °C, followed by the next 24 h of post-curing and a new cycle of measurements, 8 cycles in total. We find that contrary to industry practice to expect a high degree of cure after 3 h at 130 °C, the curing process is far from reaching the steady state of the material and continues at least for the next 72 h at 120 °C, as we observe by changes in the material electrical resistivity. If <i>TCR</i> measurements are conducted in this period, we find them significantly influenced by the post-curing process continuing in parallel, leading in particular to non-monotonic temperature dependence and the appearance of negative values. The unbiased <i>TCR</i> values we observe only when the material reaches the steady state are no longer influenced by the heat input. The dependence becomes steady, monotonically increasing from near zero value at room temperature to 0.001 1/°C at 100 °C.https://www.mdpi.com/2073-4360/15/2/433temperature coefficient of resistanceCNT/epoxy nanocompositepost-curing |
| spellingShingle | Milad Jafarypouria Biltu Mahato Sergey G. Abaimov Separating Curing and Temperature Effects on the Temperature Coefficient of Resistance for a Single-Walled Carbon Nanotube Nanocomposite Polymers temperature coefficient of resistance CNT/epoxy nanocomposite post-curing |
| title | Separating Curing and Temperature Effects on the Temperature Coefficient of Resistance for a Single-Walled Carbon Nanotube Nanocomposite |
| title_full | Separating Curing and Temperature Effects on the Temperature Coefficient of Resistance for a Single-Walled Carbon Nanotube Nanocomposite |
| title_fullStr | Separating Curing and Temperature Effects on the Temperature Coefficient of Resistance for a Single-Walled Carbon Nanotube Nanocomposite |
| title_full_unstemmed | Separating Curing and Temperature Effects on the Temperature Coefficient of Resistance for a Single-Walled Carbon Nanotube Nanocomposite |
| title_short | Separating Curing and Temperature Effects on the Temperature Coefficient of Resistance for a Single-Walled Carbon Nanotube Nanocomposite |
| title_sort | separating curing and temperature effects on the temperature coefficient of resistance for a single walled carbon nanotube nanocomposite |
| topic | temperature coefficient of resistance CNT/epoxy nanocomposite post-curing |
| url | https://www.mdpi.com/2073-4360/15/2/433 |
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