Characterization of Biobased Polyurethane Foams Employing Lignin Fractionated from Microwave Liquefied Switchgrass

Table 1

Cell diameter and number of cells by surface area () of different polyurethane foams.

Index	Lignin content (%)
	0	5	10	15
Diameter (μm)	513.4 ± 112.7	523.1 ± 89.8	521.3 ± 130.7	838.8 ± 167.1
Number of cells by surface area () (N/mm^2)	1.98	1.82	1.87	1.02