Microencapsulation Of Vanillin And Its Application To Functionalization Of Textile Fabrics

This work is a contribution to the introduction of emergent technologies in the textile sector, namely the microencapsulation of fragrances and its application to obtain value-added products.It is an efficient way to encapsulate flavor compounds by using superior wall material and choosing suitable method. This research aimed to obtain vanillin microcapsules with high encapsulation efficiency and loading rate.Preparation of β-cyclodextrin/vanillin and chitosan/vanillin microcapsules through spray-drying method has been investigated, respectively. The results show that encapusulation efficiency and loading rate of the β-cyclodextrin inclusion with vanillin using spray-drying are about108%and172%higher than those using coprecipitation method, respectively; compared with β-cyclodextrin/vanillin microcapsules, loading rate of the chitosan/vanillin microcapsules using spray-drying method increased by78%,which indicated that chitosan is an excellent encapsulant.The effect of side chain methoxy group on complexation process, binding energy and low encapsulation efficiency of vanillin within β-cyclodextrin (β-CD) was investigated by using FTIR, NMR, UV-Vis methods and quantum chemical simulation. FTIR spectra were used to prove intermolecular interaction between the two guests and β-CD. UV-Vis studies indicated that vanillin and β-hydroxybenzaldehyde both form1:1inclusion complexes with β-CD.NMR and quantum computational method gave the most favorable orientation in which the guest molecule (vanillin or p-hydroxybenzaldehyde) is totally sequestered in the hydrophobic cavity of the β-CD with the phenolic end located near the primary hydroxyls of the β-CD and the aldehyde group near the secondary hydroxyls with hydrogen bonding formation.Encapsulation efficiency of the β-CD inclusion with vanillin is about29%lower than that with PHBA.This result could be attributable to the effect that the side chain methoxy group weakened the guest/host non-covalent intermolecular interaction, specifically, hydrogen bond interaction and the stability of the complexes was weakened.Furthermore,the other aim of this work is to explain the behavior of the cotton fabrics with microcapsules bound to their fibers, to determine the relationship between their macroscopic properties and microscopic characteristics.SEM micrographs have shown an effective adhesion between microcapsules and cotton fabrics and illustrated that the vanillin microcapsules were spherical in shape.FTIR spectra corroborated by XPS techniques were used to check the success of the cross-linking reaction leading to the adhesion of microcapsules to cotton fabrics.TG-DSC results confirmed the thermal stability of cotton fabrics was improved after finishing with microcapsules.When impregnated cotton fabrics were subjected to steady temperature damp test, the remaining vanillin content was of21.2%under65℃and80%humidity condition for2h. The microcapules finished fabrics were able to keep8.6%of perfumes after the fourteen wash cycle.This work has demonstrated how the calculation and experimental studies could give reasonable results which reveal the details of β-CD complex molecule and may be a key to increased understanding of inclusion complexes formation at the molecular level.An aroma finishing method using chitosan/vanillin microcapsules was developed for textile application and may be used as a guidance to develop such products.