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Nanocellulose-based Sustainable Barrier and Antimicrobial Coatings.

紀錄類型:	書目-電子資源 : Monograph/item
正題名/作者:	Nanocellulose-based Sustainable Barrier and Antimicrobial Coatings./
作者:	Tyagi, Preeti.
出版者:	Ann Arbor : ProQuest Dissertations & Theses, : 2019,
面頁冊數:	186 p.
附註:	Source: Dissertations Abstracts International, Volume: 81-05, Section: B.
Contained By:	Dissertations Abstracts International81-05B.
標題:	Nanotechnology. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=27700914
ISBN:	9781392477021

Nanocellulose-based Sustainable Barrier and Antimicrobial Coatings.
Tyagi, Preeti.

Nanocellulose-based Sustainable Barrier and Antimicrobial Coatings. - Ann Arbor : ProQuest Dissertations & Theses, 2019 - 186 p.

Source: Dissertations Abstracts International, Volume: 81-05, Section: B.

Thesis (Ph.D.)--North Carolina State University, 2019.

This item must not be sold to any third party vendors.

The use of biomaterials, especially nanocellulose, has been limited due to their constraints for water barrier properties. The other main constraint with biomaterials used for large scale application is the cost of raw materials and limited supply. The aim of this study is to explore sustainable ways to modify nanocellulose materials including cellulose nanofibers (CNF) and cellulose nano crystals (CNC) for obtaining less hydrophilic nanocellulose-based coatings. Along with obtaining gas, oil and water barrier properties from CNF and CNC, the antimicrobial aspect was also integrated into nanocellulose coatings to improve the scope of application. The first part of the research was focused on obtaining a less hydrophilic and oleophobic sustainable modified CNC coating using a composite forming approach. For this task, CNC were preferred over CNF because the crystalline structure of CNC don't allow penetration any liquid through their crystalline packed structure. To prepare functionalized CNC-composite, additives such as high aspect ratio montmorillonite (MMT) clay, soy protein and alkyne-ketene-dimer (AKD) were employed to improve the packing density of the films. The Fourier-Transform Infrared Spectroscopy (FTIR) confirmed that fewer hydroxyl groups, which are the principal means of hydrophilicity of CNC, were exposed on the surface in CNC-composite coated paper compared to CNC. The CNC-composite coatings were confirmed to have improved water barrier properties and superior oil resistance. The second part of the research includes studying the potential of CNC-composites and CNF in a multilayer coating system. Employing CNF as bottom layer and CNC-composite as top layer was hypothesized to be the best way to minimize the surface energy of coatings along with obtaining highest oxygen and gas barrier properties. The results were validated by measuring surface energy and water contact angle hysteresis. The more hydrophobic protein moieties were confirmed over the top surface of multilayer coated paper surface using Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). A substantial increment in gas and oil barrier properties compared to commercial plastic materials and a significant improvement in water barrier properties were observed. In the third part of the research, potential of CNC along with chitosan was explored for their antimicrobial properties. There were two motives of using CNC in chitosan matrix: one, it would help in overcoming the water absorption and softness issues arising with chitosan. The second hypothesis was based upon the rod-like, rigid, stiff and narrow morphology of CNC particles; that would synergistically help chitosan as bactericidal agent by causing significant damage to the cell membrane due to its specified morphology. The morphology of rigid CNC particles protruding out of the chitosan surface was confirmed using scanning electron microscopy, auger microscopy and ToF-SIMS. The chitosan and CNC composite in a specified ratio showed a significant reduction in bacterial growth along with improving hydrophilicity of chitosan. The last part of the research (Chapter 5) was aimed at combining barrier and antimicrobial properties in one all-rounder coating recipe by changing the feedstock for preparing nanocellulose. In this work, the hemp hurds cellulose fibers were obtained using four different treatments ranging from mild (water) to a chemically intensive pulping process, namely water-autohydrolysis, mild alkaline/carbonate (4% Na2CO3), unbleached kraft, and bleached kraft. To see the impact of feedstock, hardwood (Eucalyptus) chips were also treated using similar pulping methods, except autohydrolysis. The obtained cellulose fibers were given mechanical treatment to obtain lignin containing and bleached CNF. The objective of using lignin containing hemp hurd cellulose fibers was to obtain a low-cost CNF, which are less hydrophilic and have the potential to show antimicrobial activity due to the presence of active compounds in them. The hemp hurd powder was confirmed to have the cannabidiol (CBD) using gas chromatography and mass spectrometry (GC-MS). The CBD peak in GC-MS was confirmed by comparing it with standard CBD. The antimicrobial activity of extractives from hemp hurd powder and auto hydrolyzed defibrillated cellulose fibers were confirmed against E. coli. The lignin containing CNF showed less hydrophilicity from both the feedstock hemp and Eucalyptus. The antimicrobial and barrier properties result of hemp hurd CNF gives a huge motivation to explore them deeply for qualitative and quantitative chemical characterization.

ISBN: 9781392477021Subjects--Topical Terms:

526235
Nanotechnology.
Subjects--Index Terms:

Nanocellulose

Nanocellulose-based Sustainable Barrier and Antimicrobial Coatings.
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