article i nfo Site directed therapy promises to minimize treatment-limiting systemic effects associated with cytotoxic agents that have no specificity for pathologic tissues One general strategy is to target cell surface receptors uniquely presented on particular tissues Highly specific in vivo targeting of an emerging neoplasm through a single molecular recognition mechanism has not generally been successful Nonspecific binding and specific binding to non-target cells compromise the therapeutic index of small molecule, ubiquitous cancer targeting ligands In this work, we have designed and fabricated a nanoparticle (NP) construct that could potentially overcome the current limitations of targeted in vivo delivery Quantum dots (QDs) were functionalized with a poly(ethylene glycol) (PEG) modified to enable specific cleavage by matrix metalloprotease-7 (MMP-7) The QDs were further functionalized with folic acid, a ligand for a cell surface receptor that is overexpressed in many tumors, but also expressed in some normal tissues The nanomolecular construct is designed so that the PEG initially conceals the folate ligand and construct binding to cells is inhibited MMP-7 activated peptide cleavage and subsequent unmasking of the folate ligand occurs only near tumor tissue, resulting in a proximity activated (PA) targeting system QDs functionalized with both the MMP-7 cleavable substrate and folic acid weresuccessfullysynthesizedandcharacterizedTheproteolyticcapabilityof thedualligandQDconstruct was quantitatively assessed by fluorometric analysis and compared to a QD construct functionalized with only the

Materials Science and Engineering C

The aim of this review is to provide an in-depth overview on the use of inorganic nano-sized entities for the generation of nanocomposite materials in the form of films and coatings for food packaging applications. According to recent trends toward “green” strategies, special focus has been dedicated to the development of nanocomposite coatings obtained using biopolymers as the main polymer matrix. After a first introductive part, the discussion has been addressed to the use of inorganic fillers, metals and metal-oxides, zeolites, and graphene. For each class of filler, a first ‘in-depth’ description of the most relevant physicochemical properties for the food packaging sector has been followed by case-by-case references to recent developments and envisaged implementations. The technical aspects that may be crucial in the design and end use of (bio)nanocomposite coatings have been covered in the last part of this work, which also includes an updated list of current applications on nano-sized inorganic fillers in the food packaging field.

https://pubs.rsc.org/en/content/articlepdf/2014/ra/c4ra01778a

Nanocomposite films and coatings using inorganic nanobuilding blocks (NBB): current applications and future opportunities in the food packaging sector

Nanocomposites made of poly(ethylene terephthalate) (PET) and graphene nanoplatelets (GNPs) were fabricated through micro-compounding and micro-injection molding. With an objective of improving the interactions between GNP sheets and PET chains, PET pellets were ground into a fine powder. PET pellets and powders were mixed with GNPs at 2%, 5%, 7.5%, and 10% (wt.%), molded to fabricate the nanocomposites, and then tested using several analytical characterization tools. Mechanical testing showed greater improvement through powder mixing, resulting in a 58% increase in the elastic modulus of the nanocomposites at 10% weight fraction. Thermal behavior of the nanocomposites was evaluated through differential scanning calorimetry (DSC), and it was observed that addition of GNPs into PET powders at 10% increased the crystallinity of the PET 50%. Confocal microscopy confirmed that mixing GNP with PET powders results in a more uniform distribution of the GNPs in the matrix compared to the mixture with PET pellets. X-ray diffraction (XRD) analysis confirmed the presence of GNPs with preferred orientation within the PET matrix.

Graphene/polyethylene terephthalate nanocomposites with enhanced mechanical and thermal properties

A modified melt blending method has been developed for preparing exfoliated nanocomposites of poly(ethylene terephthalate) with sodium-montmorillonite (Na-MMT) and poly(m-xylylene adipamide) with Na-MMT. In this novel compounding process, a Na-MMT water solution was blended with the polymer in a twin screw extruder. This mixing process ensured that the silica nanoparticles were exfoliated in the polymer matrix through fixing the nanoparticles within the polymer matrix almost as they were in water. Transmission electron microscopy (TEM) and X-ray diffraction were used to determine nanoparticle dispersion level. The absence of the X-ray basal reflections in conjunction with the TEM images revealed the exfoliation of clay platelets. Differential scanning calorimetry illustrated that the nucleating abilities of montmorillonite were related to clay content and dispersion morphology. Oxygen permeation results indicated that the improved morphologies had enhanced the barrier properties of the nanocomposites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Novel preparation method for enhancing nanoparticle dispersion and barrier properties of poly(ethylene terephthalate) and poly(m‐xylylene adipamide)

Copolymers of Poly(ethylene terephthalate) (PET) were synthesized by the melt polymerization of terephthalic acid (TPA) with ethylene glycol (EG) and with each of the active oxygen scavengers; monoolein (MO) and 3-cyclohexene-1,1-dimethanol (CHEDM) in separate compositions. Proton nuclear magnetic resonance spectroscopy (1H NMR) and 2D correlation spectroscopy (COSY) indicated that PET had reacted with both MO and CHEDM at their hydroxyl end groups. Oxygen barrier properties of the MO and CHEDM copolymers exhibited improvements of up to 40%, in comparison to an unmodified commercial PET. Effects of the oxygen scavengers on the copolymers' physical properties were investigated in terms of their crystallization, melting, and rheological behaviors. Both types of copolymers showed decreases in peak melting temperatures with increased scavenger concentrations and also crystallized more slowly as the scavenger concentrations increased. The PET/MO copolymer showed non-Newtonian rheological behavior with higher MO concentration; while the PET/CHEDM copolymers showed Newtonian behavior within the studied range of CHEDM concentrations. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Development of active barrier systems for poly(ethylene terephthalate)

Natural montmorillonite (MMT) clay nanomaterials were successfully dispersed in poly(ethylene terephthalate) (PET) through two new and enhanced in situ polymerization methods. In the case of PET/MMT nanocomposites prepared through the esterification (ES) reaction clay-addition method, unmodified MMT clays were dispersed in water and, then, the ethylene glycol monomer of PET before the preparation of bis(2-hydroxyl ethyl) terephthalate (BHET) nanocomposites, which later underwent in situ polymerization. For nanocomposites prepared through the polycondensation (PC) reactor method, selected amounts of clay were dispersed in ethanol, with stirring inside the reactor. A portion of crushed BHET was then added to the PC reactor, and the combined mixture was stirred to achieve dispersion. The remaining BHET was added and mixed, the ethanol was evaporated by heating, and in situ polymerization was initiated. Morphological analysis by X-ray diffraction and transmission electron microscopy confirmed the presence of exfoliated and intercalated clay structures in the nanocomposites prepared through both ES and PC clay-addition methods. Nanocomposites containing lower concentrations of clay showed increases in the oxygen barrier properties in comparison to values obtained for the unmodified PET. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Improved method for dispersing clay in a monomer or bis(2-hydroxyl ethyl terephthalate) before in situ polymerization of poly(ethylene terephthalate)/montmorillonite nanocomposites

.........................................................................................iii ACKNOWLEDGEMENT...........................................................................vi TABLE OF CONTENT...............................................................................vii LIST OF FIGURES..................................................................................xi LIST OF TABLES...................................................................................xvi CHAPTER

Rohan Khushal Labde

Papers

Improved method for dispersing clay in a monomer or bis(2-hydroxyl ethyl terephthalate) before in situ polymerization of poly(ethylene terephthalate)/montmorillonite nanocomposites

Preparation and Characterization of Polyethylene Terephthalate/Montmorillonite Nanocomposites by In-situ Polymerization Method