A complete description on effect of β-cyclodextrin-ester as a bio-based additive for preparation of safe PVC: From synthesis to computational study

Abstract

Due to existing additive in the PVC product in some crucial fields for example, toys and biomedical devices, migration of Di-2-ethylhexyl phthalate (DEHP) can be hazardous to human health. Therfore migration of DEHP has caused a wide concern and this problem must be solved. In the present study, a water-insoluble β-cyclodextrin-ester (β -CDPN) was synthesized by reaction of β-cyclodextrin with terephthaloyl chloride as a cross-linker using micro-emulsion method. The β -CDPN loading DEHP was introduced to Polyvinyl chloride (PVC) as an active inhibitor to reduce DEHP migration. DEHP migration was determined using the UV–vis spectroscopy. It was found that the addition of β -CDPN can decrease the levels of DEHP migration from the tree component sample containing β -CDPN by almost 57 % as compare with PVC-DEHP sample. Also the anti-migration efficiency results showed improvement about 57.19 %. Mechanical properties of β -CDPN and DEHP including the tensile strength (TS), Young’s modulus (YM) and elongation at break (EB) were investigated. The results of mechanical properties indicated that all the mechanical data in this samples were slightly improved in the presence of β -CDPN by loading DEHP as compare to the PVC/DEHP system. The PVC films containing 2.4 mass% of β –CDPN showed the increasing in tensile strength (13 %), Young’s modulus (6 %) and elongation at break (7.2 %) values as compare to the PVC/DEHP. Also, computational method was used to investigate the inclusion complex of DEHP and β -CDPN and also inclusion shape and orientation. Based on the obtained results, it can be suggested that the most energetically favorable structure is in the form that aromatic group of DEHP enters into the cavity of β -CDPN through its wide rim. Altogether the results showed that the synthesized β -CDPN has large potential as green inhibitor to reduce DEHP migration. This could be a promising option to overcome the environmental problems caused by DEHP plasticizer.