Introduction
Materials and method
Polyurethane precursors
Description | Trade name | Mass/g |
---|---|---|
Polyether Polyol | Caradol MC28-02 | 10 |
Polypropylene glycol (PPG-400) | ALCUPOL D4011 | 5 |
Monoethylene glycol | MEG | 10 |
Catalyst | Dabco 33-LV | 0.3 |
Moisture scavenger | Finmasorb 430 PR | 5 |
4,4′-Diphenylmethane diisocyanate (MDI) | ONGRONAT XP 1117 | 29.92–30.60(a) |
Benzoic Acid | – | 2, 4, 6 |
4(para)-nitro-benzoic acid | – | 2, 4, 6 |
3, 5- din-nitro-benzoic acid | – | 2, 4, 6 |
Synthesis method (Solution casting)
Results and discussion
Effect of doping on electrical properties
Dielectric constant and Loss factor
Sample Name | Capacitance (C, pF) | Loss factor (D) | Permittivity (ε, pFm−1) | Dielectric constant (εr) |
---|---|---|---|---|
Pure PU | 55.15 | 0.0452 | 48.666 | 5.499 ± 0.601 |
PU + 2% BA | 59.22 | 0.0476 | 54.878 | 6.201 ± 0.101 |
PU + 4% BA | 58.14 | 0.0515 | 51.312 | 5.798 ± 0.302 |
PU + 6% BA | 63.20 | 0.0518 | 55.772 | 6.302 ± 0.202 |
PU + 2% PNBA | 65.76 | 0.0593 | 57.454 | 6.492 ± 0.226 |
PU + 4% PNBA | 66.73 | 0.0997 | 58.887 | 6.654 ± 0.064 |
PU + 6% PNBA | 68.90 | 0.112 | 62.020 | 7.008 ± 0.290 |
PU + 2% DNBA | 69.26 | 0.1 | 59.295 | 6.7 ± 0.241 |
PU + 4% DNBA | 66.60 | 0.112 | 60.542 | 6.841 ± 0.100 |
PU + 6% DNBA | 71.60 | 0.112 | 64.454 | 7.283 ± 0.342 |
DC volume resistivity
Sample Name | Resistance (R, MΩ) | Volume Resistivity (ρ, Ω-cm) |
---|---|---|
Pure PU | 1.75 × 103 | 7.727 × 1011 |
PU + 2% BA | 0.7 × 103 | 2.943 × 1011 |
PU + 4% BA | 0.32 × 103 | 1.412 × 1011 |
PU + 6% BA | 0.29 × 103 | 1.280 × 1011 |
PU + 2% PNBA | 2.45 × 102 | 1.092 × 1011 |
PU + 4% PNBA | 0.65 × 102 | 2.870 × 1010 |
PU + 6% PNBA | 1.22 × 101 | 5.281 × 109 |
PU + 2% DNBA | 7.9 × 101 | 3.596 × 1010 |
PU + 4% DNBA | 4.6 × 101 | 1.972 × 1010 |
PU + 6% DNBA | 1.7 × 101 | 7.359 × 109 |
Effect of doping on thermo-mechanical properties
Differential scanning calorimetry (DSC)
Sample name | DSC | DMA | ||
---|---|---|---|---|
Tg, SS / °C | Tg, HS / °C | Tg, SS / °C | Tg, HS / °C | |
Pure PU | -59 | NA | -48 | -1 |
PU + 2% BA | -56 | NA | -47 | -3 |
PU + 4% BA | -57 | NA | -49 | -8 |
PU + 6% BA | -54 | NA | -44 | -11 |
PU + 2% PNBA | -62 | NA | -50 | 0 |
PU + 4% PNBA | -59 | NA | -46 | -7 |
PU + 6% PNBA | -59 | NA | -47 | -4 |
PU + 2% DNBA | -62 | NA | -50 | 6 |
PU + 4% DNBA | -63 | NA | -49 | 8 |
PU + 6% DNBA | -63 | NA | -48 | 0.5 |
Dynamic mechanical analysis (DMA)
Thermal conductivity
Doping Content (%) | Thermal conductivity (Wm−1 K−1) |
---|---|
Pure PU | 0.26 |
PU + 2% BA | 0.26 |
PU + 4% BA | 0.25 |
PU + 6% BA | 0.25 |
PU + 2% PNBA | 0.26 |
PU + 4% PNBA | 0.28 |
PU + 6% PNBA | 0.35 |
PU + 2% DNBA | 0.31 |
PU + 4% DNBA | 0.39 |
PU + 6% DNBA | 0.28 |