Kinetics and Mechanisms of the Oxidation Processes for Unsaturated-hydrocarbon-modified Scavengers
Kinetics and Mechanisms of the Oxidation Processes for Unsaturated-hydrocarbon-modified Scavengers

Author: Hao Li

Publisher:

Published: 2010

Total Pages: 221

ISBN-13:

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Poly(ethylene Terephthalate) (PET) is a prominent packaging material which is widely used in the plastic packaging industry. When compared with traditional packaging materials, such as steel and glass, the oxygen barrier property of PET is moderate at ambient temperature. The moderate oxygen barrier property of PET limits the application of PET for packaging some oxygen sensitive products, such as beer. Several approaches have been made to enhance "shelf life" of PET packaging material, especially for oxygen sensitive foods. The active barrier packaging technique, which absorbs oxygen during its permeation route into packaged article, was studied in this research. Unsaturated hydrocarbons were used to modify PET to develop an oxygen scavenging system which can react with oxygen as an oxygen scavenger. In this research the unsaturated hydrocarbon is low molecular weight hydroxyl terminated polybutadiene. After the modification, the modified PET should maintain the favorable properties of PET and have an oxygen scavenging capability. The reason for blending hydroxyl terminated polybutadiene (HTPB) and PET was that the hydroxyl end group of HTPB was expected to react with end groups of PET to form a copolyester. The PET/HTPB copolyester will have different optical, thermal and mechanical properties than those of a unreacted PET/PBD physical blend. In this research, the oxidation mechanisms and kinetics of pure polybutadiene was studied first. Factors such as the molecular weight and composition of polybutadiene, which can affect oxidation mechanisms and kinetics, were analyzed. Activation energies of unsaturated olefin groups in the oxidation reactions were obtained. In the second portion of this research, low levels of hydroxyl terminated polybutadiene were reactively extruded with PET to form a polybutadiene modified PET. The oxidation kinetics and mechanism of this polybutadiene modified PET were also studied. Factors that can affect oxidation kinetics, such as the molecular weight of polybutadiene, concentration of polybutadiene, dispersion effect of polybutadiene in the modified PET and catalyst effect on oxidation kinetics, were included in the study of this unsaturated hydrocarbon modified PET. The reactions between hydroxyl terminated polybutadiene and PET during the reactive extrusion process were also confirmed and identified by infrared end group analysis method, a proton NMR method and a content extraction method. The evaluation of reactive extrusion process between polybutadiene and PET, were also studied. Finally suggestions were made on the future study of oxygen scavenging packaging techniques.

Metal-Containing Polymeric Systems
Metal-Containing Polymeric Systems

Author: John E. Sheats

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 521

ISBN-13: 1461594154

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Research on metal-containing polymers began in the early 1960's when several workers found that vinyl ferrocene and other vinylic transition metal u -com plexes would undergo polymerization under the same conditions as conventional organic monomers to form high polymers which incorporated a potentially reactive metal as an integral part of the polymer structures. Some of these materials could act as semi-conducters and pos sessed one or two dimensional conductivity. Thus appli cations in electronics could be visualized immediately. Other workers found that reactions used to make simple metal chelates could be used to prepare polymers if the ligands were designed properly. As interest in homo geneous catalysts developed in the late 60's and early 70's, several investigators began binding homogeneous catalysts onto polymers, where the advantage of homo geneous catalysis - known reaction mechanisms and the advantage of heterogeneous catalysis - simplicity and ease of recovery of catalysts could both be obtained. Indeed the polymer matrix itself often enhanced the selectivity of the catalyst.

Organometallic Polymers
Organometallic Polymers

Author: Charles E. Jr. Carraher

Publisher: Elsevier

Published: 2012-12-02

Total Pages: 368

ISBN-13: 0323153909

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Organometallic Polymers focuses on the synthesis, characterization, and potential applications of organometallic polymers. The discussion is organized around seven themes: vinyl polymerization of organometallic monomers; condensation polymerization of organometallic monomers; polymer-bound catalysts; applications of organotin polymers; developments in organosilicon polymers; phosphonitrile and sulfur nitride polymers; and coordination polymers. This book is comprised of 33 chapters and begins with a general review of polymerized vinyl monomers containing transition metals, as well as the reactivity of such monomers in addition to homo- and copolymerizations. The following chapters explore the participation of the ferrocene nucleus in the polymerization of vinylferrocene and its effect on polymer properties; thermomechanical transitions of ferrocene-containing polymers; photocrosslinkable organometallic polyesters; and supported catalysts for ethylene polymerization. The remaining sections discuss antifouling applications of various tin-containing organometallic polymers; structure and applications of polyphosphazenes and polymeric sulfur nitride; and coordination of inorganic ions to polymers. This monograph will be a useful resource for organic chemists and research workers in the field.

Inorganic and Metal-Containing Polymeric Materials
Inorganic and Metal-Containing Polymeric Materials

Author: Charles E. Carraher Jr.

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 506

ISBN-13: 1461306698

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Research on metal-containing polymers began in the early 1960's when several workers found that vinyl ferrocene and other vinylic transition metal TI -complexes would undergo polymerization under the same conditions as conventional organic monomers to form high polymers which incorporated a potentially reactive metal as an integral part of the polymer structures. Some of these materials could act as semi conductors and possessed one or two dimensional conductivity. Thus applications in electronics could be visualized immediately. Other workers found that reactions used to make simple metal chelates could be used to prepare polymers if the ligands were designed properly. As interest in homogeneous catalysts developed in the late 60's and early 70's, several investigators began binding homogeneous catalysts onto polymers, where the advantage of homogeneous catalysis - known reaction mechanisms and the advantage of heterogeneous catalysis - simplicity and ease of recovery of catalysts could both be obtained. Indeed the polymer matrix itself often enhanced the selectivity of the catalyst. The first symposium on Organometallic Polymers, held at the National Meeting of the American Chemical Society in September 1977, attracted a large number of scientists interested in this field, both established investigators and newcomers. Subsequent symposia in 1977, 1979, 1983, and 1987 have seen the field mature. Hundreds of papers and patents have been published.