Table 1.

Amount of reagents used to synthesize elastomers A1‐A4 and B1‐B3 and key properties of the resulting materials including T _g, Young's modulus at 10% strain (Y _10%), elongation at break, and permittivity at 100 kHz (ε'). The amount of initiator tetrabutylphosphonium hydroxide (TBPH) was kept constant at 25 µL (0.92 mol%)

Elastomer	D4 CN [g]	D4 CN [mol%]	D4 [g]	D4 [mol%]	tris‐D4 [mg]	tris‐D4 [mol%]	T g [°C]	Y 10% [kPa] a)	Elong. [%]	ε' (100 kHz)
A1	2	100	–	–	20	0.52	−59.0	130 ± 4	59 ± 3	18.1 ± 0.1
A2	2	100	–	–	50	1.3	−59.1	168 ± 12	48 ± 1	17.4 ± 0.6
A3	2	100	–	–	100	2.6	−59.0	176 ± 6	43 ± 2	17.3 ± 0.2
A4	2	100	–	–	150	3.9	−58.8	202 ± 10	41 ± 3	16.9 ± 0.3
B1	1	50	0.59	50	20	0.52	−74.3	178 ± 8	87 ± 6	12.7 ± 0.7
B2	1	50	0.59	50	50	1.3	−73.8	274 ± 3	64 ± 5	12.7 ± 0.2
B3	1	50	0.59	50	100	2.6	−74.1	444 ± 15	33 ± 1	12.7 ± 0.3

^a) Young's moduli were determined from the slope of the stress–strain curves with a linear fit in the first 10% of strain.