Formation of Beta-Cyclodextrin Inclusion Complex with a Phenolic Antioxidant and its Industrial Applications in Polyethylene Film

Abstract

AGRAWAL, MANISHA. Formation of [beta]-Cyclodextrin Inclusion Complex with a Phenolic Antioxidant and its Industrial Applications in Polyethylene Film. (Under the guidance of Dr. Hyun Suk Whang)

Butylated hydroxytoluene (BHT) is a phenolic antioxidant, which is primarily used in food additives. Due to its high volatility, it can be suspected to have losses through volatilization in high temperature applications. However, there is barely any research work focused on the formation of BHT-[beta]-CD-IC. In this study, we have successfully formed the inclusion compound between BHT and [beta]-CD (BHT-[beta]-CD-IC) and characterized it using wide-angle x-ray diffraction (WAXD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), nuclear magnetic resonance spectroscopy (NMR) and ultra violet visible spectroscopy (UV-Vis). We produced on pilot scale three sets of low density polyethylene (LDPE) films with the addition of BHT, [beta]-CD, and BHT-[beta]-CD-IC. The determination of BHT content in the films was carried out using Gas Chromatography- Mass Spectrometry (GC-MS). The results show that 44% BHT was lost from BHT-[beta]-CD-IC LDPE films while 78% BHT was lost from the BHT LDPE film. Hence, the complex proved to be more efficient in preventing loss of BHT due to encapsulation of volatile guest. In addition, microscopy studies indicate that BHT-[beta]-CD-IC LDPE film shows small aggregates uniformly distributed over a large range in the LDPE matrix. The oxidative performance of the films was studied using differential scanning calorimetry (DSC) for determining the oxidation induction time (OITtime) and oxidation induction temperature (OITtemp.). It was found that OITtemp.method is less sensitive as compared to the OITtime method. The OITtime was 35 min for the BHT-[beta]-CD-IC LDPE film as compared with 16 min and 26 min values of LDPE and BHT LDPE films, respectively. Hence, the encapsulation of BHT in the CD maximizes the efficiency and stability to thermal degradation for BHT-[beta]-CD-IC film. The viscoelastic behavior of the films was also studied using dynamic mechanical analysis (DMA). The results indicate increase in storage modulus (El) and loss modulus of the complex (Ell). Also, the maxima of tan delta (Ell/El) for LDPE films processed with BHT, [beta]-CD and BHT-[beta]-CD-IC are shifted to lower temperature. Further, a migration study of BHT from the complex using food stimulant, which is underway, will give an insight on the controlled release of active component in the film. This may open a great potential for industrial applications of CD-ICs.