Table 1.

The symbols and the molar ratio of substrates used in the synthesis of unmodified PU foams.

Type	Symbol	Polyester PEBA	Chain extender BDO	Chain extender EHEE	Water	Catalyst DABCO	Isocyanate HDI
Series I	PU-0.8/BDO/G0*	0.582	0.116	—	0.017	0.008	0.278
	PU-0.9/BDO/G0	0.560	0.112	—	0.017	0.007	0.303
	PU-1/BDO/G0	0.544	0.109	—	0.016	0.007	0.323
	PU-1.1/BDO/G0	0.525	0.105	—	0.016	0.007	0.347
Series II	PU-0.8/EHEE/G0	0.539	—	0.178	0.016	0.007	0.260
	PU-0.9/EHEE/G0	0.522	—	0.172	0.016	0.007	0.283
	PU-1/EHEE/G0	0.507	—	0.167	0.015	0.007	0.303
	PU-1.1/EHEE/G0	0.490	—	0.1618	0.015	0.007	0.327

*PU: polyurethane; 0.8 molar ratio of NCO : OH (0.8 : 1); BDO or EHEE: type of chain extender.