Table 6.

Reaction compositions for cross-linking of the thirteen formulations.

Formulations	Point type	Factors
		Conc. of ECH (%, w/w)	Cross-linking time (h)
F-1	Factorial	3.00 (-1)	1.00 (-1)
F-2a	Factorial	16.00 (+1)	1.00 (-1)
F-3	Factorial	3.00 (-1)	10.00 (+1)
F-4	Factorial	16.00 (+1)	10.00 (+1)
F-5b	Axial	0.31 (-α)	5.50 (0)
F-6c	Axial	18.69 (+α)	5.50 (0)
F-7d	Axial	9.50 (0)	0.86 (-α)
F-8e	Axial	9.50 (0)	11.86 (+α)
F-9	Center point	9.50 (0)	5.50 (0)
F-10	Center point	9.50 (0)	5.50 (0)
F-11	Center point	9.50 (0)	5.50 (0)
F-12	Center point	9.50 (0)	5.50 (0)
F-13	Center point	9.50 (0)	5.50 (0)