Long-Chain Alkylimidazolium Ionic Liquid Functionalization of Cellulose Nanofibers and Their Embedding in HDPE Matrix

Table 1

Cellulose structural parameters obtained from FTIR and XRD spectra.

Material	FTIR analysis		XRD analysis
	CrI	LOI	Cr (%)	(nm)
CelNFs	0.084	1.75	76.41	2.26	0.24
CelNFs-IL 25°C	0.056	1.08	43.75	2.47	0.28
CelNFs-IL 35°C	0.050	0.84	40.62	3.61	0.48

CrI is the crystallinity index of the material (determined from the area ratio of the characteristic bands from the FTIR spectra, proportional to the content of cellulose I and cellulose II from the material).
LOI is the lateral order index of the material, proportional to the cellulose I content in the fibers (determined from FTIR spectroscopy).
Cr is the absolute crystallinity of the material, determined from the XRD diffractogram, as total contribution of the cellulose I and cellulose II anomer.
represents the apparent cellulose crystallite dimensions, determined from the XRD diffractogram, relative to that of the defect-free 100% crystalline cellulose I anomer.
represents relative proportion of cellulose crystallite interior chains, related to more tight packing of the cellulose architecture. As structure modification and functionalization of cellulose occur, values also increase.