تحضير وتوصيف ألياف نانوية مضادة للبكتريا بتقنية الغزل الكهربائي لتطبيقات تغليف المواد الغذائية

الباحث

رسل محمد عبد الرضا فليح

المشرف

هناء جواد كاظم - علي عبد الأمير الزبيدي

الجامعة

جامعة بابل

الكلية / القسم

هندسة المواد / هندسة البوليمر والصناعات البتروكيمياوية

الشهادة

دكتوراه

السنة

2022

لغة الرسالة

انكليزي

الكلمات المفتاحية

Electrospinning;Nanofibers;Food packaging;Antibacterial

Nowadays, polymeric materials are widely used in the development of food packages, especially when increment demand for food quality and safety. So it was necessary to develop efficient packaging strategies for prolonging the shelf life of food. Meanwhile, packaging field has been focused on the production of functional materials able to reach such further protection as repression of microorganism growth, resistance to oxidation, and stability against environmental hazards. By using a new technique as electrospinning technique which different from traditional techniques. So employing a bio-based functional layer/coating on a polymeric layer as food packaging material could be a potential way to available this protection for foods. Hence in this thesis, the main objective was to used natural environmentally friendly materials and non- toxic solvent for purpose of sustainability and minimize the consumption of synthetic materials. Thus three parts were prepared in this thesis. The first part consists of utilization starch (ST) and cress seed mucilage (CSM) as a new source of bio macromolecules and natural polymers has piqued attention in food packaging as two separate blend with PVA (polyvinyl alcohol) which used as a spin ability aid. Afterward, the two blend from PVA-ST-CSM were combined in various volume ratios and selected the ideal volume ratio based on the highest contact angle was (40:30:30) which was choice the basic blend to prepare the second part of nanofiber mats was strengthen by different filler additions from essential oils, such as ((moringa oil (MO), cardamom oil (CO), clove bud oil (CBO), thyme oil (TO), and fenugreek oil (FO)) in various concentration (1, 5, and 10%). Furthermore, to another filler from walnut tree bark (WB) powder in different percentage (0.3, 0.5, 0.7 wt.%) and were examined by Field-Emission Scanning Electron Microscopy (FESEM), Wettability test, and Atomic Force Microscopy (AFM). As well as to biological tests as Anti-bacterial activity and Anti-oxidant activity. Based on these findings was chosen the best percentage from these additions which was (10%) from essential oils and (0.5%) of (WB). These percentages was selected to prepare the third part which represent the final blend and was studied the structural and physical characteristics by (FESEM), Wettability test, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), (AFM), Ultraviolet- visible Spectrophotometer (UV), X-Ray Diffraction (XRD) and Thermogravimetric Analysis (TGA). As well as to biological tests as Anti-bacterial activity, Anti-oxidant activity and Anti-fungi activity and mechanical test such as Nano-indentation. The results clarified that by increasing the WCA value from (74.049o to 105.358o) for basic sample and final sample respectively. While the average diameter and surface roughness increased from ((86.873 to 277.302 nm) and (159.012 to 210.046 nm) of basic and final sample respectively. In addition, the morphology of final sample consist of multi-layer strand that can fill pores of the membranes. Thus, affect on the air permeability of nanofiber web which can be considered as feasible for food packaging applications. FTIR results showed that just physical reactions existed among the components and no chemical reactions occurred. The nanofibers of basic sample have not antibacterial and antifungal properties, while nanofibers containing all additives (final sample) show antibacterial activity against E. coli about (37%) and S. aureus about (20%) and antifungal against candida bacteria about (18%). As well as, incorporating all additives in basic sample improved the antioxidant of the generated nanofibers. The amount of radical scavenging for the basic sample was (37%) and increasing up to (55%) for final sample. Observed the young modulus from nano-indentation test increased thus the tensile strength increasing and these properties necessary for the effective packaging to retain its shape under food loading and during their storage. Different fruits and vegetables were packed in a plastic container and closed by nanofiber mats and without nanofiber. All samples were observed after a specific period of time which was 10 days in room temperature. The results observed that fruits and vegetables closed by nanofiber exhibited better freshness as compared to that without nanofiber. From the results of performed tests, it was observed that nanofiber mats possess enough morphological, structural, biological, mechanical and physical properties to be used as food packaging.

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