Open Access. Powered by Scholars. Published by Universities.®

Polymer Science Commons

Open Access. Powered by Scholars. Published by Universities.®

1,397 Full-Text Articles 1,622 Authors 149,507 Downloads 55 Institutions

All Articles in Polymer Science

Faceted Search

1,397 full-text articles. Page 5 of 48.

Fractionation Of Cornstalk Into Cellulose And Lignin For The Production Of Sodium Carboxymethyl Cellulose, Tao Shui 2016 The University of Western Ontario

Fractionation Of Cornstalk Into Cellulose And Lignin For The Production Of Sodium Carboxymethyl Cellulose, Tao Shui

Electronic Thesis and Dissertation Repository

This thesis project aimed to fractionate cornstalk into cellulose and lignin, and utilize the crude cornstalk-derived cellulose for the production of sodium carboxymethyl cellulose and the lignin for the sybthesis of bio-based phenol-formaldehyde resole resins as wood adhesives. In this thesis work, cornstalk was efficiently fractionated into crude cellulose and crude lignin in mixed solvents of acetic acid, formic acid and water at a solid/agent ratio of 1:5 (g/mL) at 80-100 °C for 120-240 min. The best conditions for organosolv fractionation of cornstalk among the test conditions were determined as follows: mixed solvent of acetic acid/formic ...


Microbial Nanoculture As An Artificial Microniche, Tagbo H. R Niepa, Likai Hou, Hongyuan Jiang, Mark Goulian, Hyun Koo, Kathleen J. Stebe, Daeyeon Lee 2016 University of Pennsylvania

Microbial Nanoculture As An Artificial Microniche, Tagbo H. R Niepa, Likai Hou, Hongyuan Jiang, Mark Goulian, Hyun Koo, Kathleen J. Stebe, Daeyeon Lee

Departmental Papers (CBE)

Microbes self-organize in microcolonies while transitioning to a sessile form within a protective biofilm matrix. To enable the detailed study of microbial dynamics within these microcolonies, new sessile culture systems are needed that sequester cells and mimic their complex growth conditions and interactions. We present a new nanoliter-scale sessile culture system that is easily implemented via microfluidics-enabled fabrication. Hundreds of thousands of these nanocultures can be easily generated and imaged using conventional or confocal microscopy. Each nanoculture begins as a several nanoliter droplet of suspended cells, encapsulated by a polydimethylsiloxane (PDMS) membrane. The PDMS shell provides long-lasting mechanical support, enabling ...


Directed Self-Assembly Of Block Copolymer, No1, Hiromichi Yamamoto 2016 Singh Center

Directed Self-Assembly Of Block Copolymer, No1, Hiromichi Yamamoto

Protocols and Reports

The PS-rich and neutral PS-b-PMMA block copolymer (BCP) films were spin coated on the neutral random copolymer hydroxyl-terminated PS-r-PMMA layers grafted on the native oxide and 50 nm thick PECVD amorphous silicon oxide layers. Relationship between the grafting density of BCP and surface density of hydroxyl moiety on silicon oxide is discussed. Furthermore, optimization of annealing BCP films is reported, and wetted and de-wetted BCP films are shown in optical microscope images. In addition, finger print and nanopore structures of BCP films are also indicated in SEM images.


Mass And Charge Transport In Hydrated Polymeric Membranes, Marshall T. McDonnell 2016 University of Tennessee, Knoxville

Mass And Charge Transport In Hydrated Polymeric Membranes, Marshall T. Mcdonnell

Doctoral Dissertations

Mass and charge transport through hydrated polymer membranes has significant importance for many areas of engineering and industry. Multi-scale modeling and simulation techniques were used to study transport in relation to two specific membrane applications: (1) food packaging and (2) additives for polymer electrolytes.

Chitosan/chitin films were studied due to their use as a sustainable, biodegradable food packaging film. The effects of hydration on the solvation, diffusivity, solubility, and permeability of oxygen molecules in these films were studied via molecular dynamics and confined random walk simulations. With increasing hydration, the membrane was observed to have a more homogeneous water ...


Film Performance Of Poly(Lactic Acid) Blends For Packaging Applications, Carlos A. Diaz, HsunPao Y. Pao, Sungyoung Kim 2016 Rochester Institute of Technology

Film Performance Of Poly(Lactic Acid) Blends For Packaging Applications, Carlos A. Diaz, Hsunpao Y. Pao, Sungyoung Kim

Journal of Applied Packaging Research

Poly(lactic acid) (PLA), a biodegradable thermoplastic derived from renewable resources, stands out as a substitute to petroleum-based plastics. PLA based films for food packaging has been an area of both commercial and research interest within the context of sustainability. In spite of its high strength, packaging applications have been limited because PLA is more brittle than traditional oil-based plastics. Because of this, films display low tear and impact resistance and produce a loud crackling sound when manipulated. Although many studies address the toughening of PLA in the bulk, little attention has been placed on the film performance. The present ...


Occurrence Of Reverse Side Effects In Corona Treatment Of Dispersion-Coated Paperboard And Its Influence On Grease Barrier Properties, Sami-Seppo Ovaska, Ringaudas Rinkunas, Tadeusz Lozovksi, Robertas Maldzius, Jonas Sidaravicius, Leena-Sisko Johansson, Monika Österberg, Kaj Backfolk 2016 Lappeenranta University of Technology, Group of Packaging Technology

Occurrence Of Reverse Side Effects In Corona Treatment Of Dispersion-Coated Paperboard And Its Influence On Grease Barrier Properties, Sami-Seppo Ovaska, Ringaudas Rinkunas, Tadeusz Lozovksi, Robertas Maldzius, Jonas Sidaravicius, Leena-Sisko Johansson, Monika Österberg, Kaj Backfolk

Journal of Applied Packaging Research

The uncoated side of dispersion-barrier-coated paperboards was exposed to positive and negative direct current corona treatments in order to confirm the occurrence of backside treatment and clarify its effects on the usability of the paperboard. The main component of the coating dispersions was hydroxypropylated potato starch and the effects of talc and styrene-butadiene latex additions on backside treatment were evaluated. Coatings with a high talc proportion showed excellent initial grease resistance, but corona-induced strikethroughs caused a drastic decrease in grease penetration time. The root-mean-square roughness measurements revealed moderate surface roughening at the backside, indicating thus backside treatment. The alterations in ...


Atomic Force Microscopy Of Poly(Ethylane-Oxide) Crystalization, Xavier Capaldi 2016 Union College - Schenectady, NY

Atomic Force Microscopy Of Poly(Ethylane-Oxide) Crystalization, Xavier Capaldi

Honors Theses

Polymer crystallization is a complex process which is influenced by a variety of factors. Atomic force microscopy is used to explore the material properties of polymer crystals. Poly(ethylene-oxide) is used in a variety of molecular weights as the sample. In addition, a variety of sample preparation methods and microscopy modes were tested. A relatively new imaging technique was identified for the characterization of polymer crystals: amplitude modulation-frequency modulation viscoelastic mapping. This mode was used to measure material properties such as stiffness and dissipation.


Biodegradable Magnesium Alloys For Orthopaedic Applications: A Review On Corrosion, Biocompatibility And Surface Modifications., Sankalp Agarwal, James Curtin, Brendan Duffy, Swarna Jaiswal 2016 Dublin Institute of Technology

Biodegradable Magnesium Alloys For Orthopaedic Applications: A Review On Corrosion, Biocompatibility And Surface Modifications., Sankalp Agarwal, James Curtin, Brendan Duffy, Swarna Jaiswal

Articles

Magnesium (Mg) and its alloys have been extensively explored as potential biodegradable implant materials for orthopaedic applications (e.g. Fracture fixation). However, the rapid corrosion of Mg based alloys in physiological conditions has delayed their introduction for therapeutic applications to date. The present review focuses on corrosion, biocompatibility and surface modifications of biodegradable Mg alloys for orthopaedic applications. Initially, the corrosion behaviour of Mg alloys and the effect of alloying elements on corrosion and biocompatibility is discussed. Furthermore, the influence of polymeric deposit coatings, namely sol-gel, synthetic aliphatic polyesters and natural polymers on corrosion and biological performance of Mg and ...


Microstructure And Rheology Of Carbon Nanotubes At Air-Water Interfaces, Charles D. Young 2016 University of Connecticut - Storrs

Microstructure And Rheology Of Carbon Nanotubes At Air-Water Interfaces, Charles D. Young

Honors Scholar Theses

This work characterizes the material properties of carbon nanotubes at air-water interfaces for potential use in creating stable emulsions. Properties such as length, aspect ratio, contact angle, microstructural ordering, surface pressure, compression and shear elastic moduli, stresses, surface viscosities and non-linearity are explored. Challenges such as deviation from a classical analysis of monolayers are encountered in the form of aggregation, mechanical contributions, and interface relaxation. These factors are taken into account to explain experimental measurements and trends. Ultimately, existing models for more homogeneous systems are resolved with observations to offer insight and areas of promise moving forward.


Synthesis And Characterization Of Interpenetrating Polymer Networks For Applications In Extraterrestrial Radiation Shielding, Josiah Arevalo Hammack 2016 College of William and Mary

Synthesis And Characterization Of Interpenetrating Polymer Networks For Applications In Extraterrestrial Radiation Shielding, Josiah Arevalo Hammack

Undergraduate Honors Theses

During interplanetary voyages spacecraft are exposed to a variety of ionizing radiations, including high intensity electromagnetic radiation and galactic cosmic rays, creating conditions that are harmful to both instrumentation and human passengers. Current shielding methods offer a degree of protection, but they are not suitable for long term missions or for habitation on extraterrestrial environments, and traditional terrestrial shields are too heavy to be carried on these missions. Organic polymers offer a versatile, lightweight solution to many of the difficulties in shielding, however they also present difficulties establishing a sufficiently high hydrogen content while maintaining high mechanical and thermal stability ...


Polymer System And Molding Techniques For Surgical Training Models, Daniel J. Park 2016 The University of Western Ontario

Polymer System And Molding Techniques For Surgical Training Models, Daniel J. Park

Electronic Thesis and Dissertation Repository

Poly(vinyl alcohol) (PVA) hydrogels are used to produce high fidelity models for surgical training applications. PVA hydrogel mechanical properties are developed through the use of a freeze-thaw cycling, physical crosslinking process. The resulting gels exhibit a non-linear elastic modulus which can be tailored to match many tissues of the human body.

Methods for joining PVA hydrogels were investigated to aid in the production of complicated structures that would be difficult to produce in a single step. Bond strength of PVA gels was characterized using a modified peel test. The porosity and degree of crosslinking of the PVA substrate were ...


Engineered Quantum Dots For Eva Nanocomposite Films And Tio2 Photocatalysts, Md Abdul Mumin 2016 The University of Western Ontario

Engineered Quantum Dots For Eva Nanocomposite Films And Tio2 Photocatalysts, Md Abdul Mumin

Electronic Thesis and Dissertation Repository

Light absorbing inorganic nanoparticles in transparent plastics such as poly(ethylene-co-vinyl acetate) (EVA) are of enormous interest in emerging solar materials, including photovoltaic (PV) modules and commercial greenhouse films. Quantum dots (QDs) have the potential to absorb UV light and selectively emit visible light. However, how to stabilize the QDs for long product life spans without "blinking" while enabling their easy integration into polymer systems is lacking. This work examines different approaches for loading mesoporous silica encapsulated QDs into EVA polymer films which can control plant growth in greenhouses or enhance PV panel efficiencies.

Highly luminescent CdS and CdS-ZnS core-shell ...


Design And Implementation Of Multi-Responsive Azobenzene Triggers In Self-Immolative And Degradable Polymers, Andrew D. Wong 2016 The University of Western Ontario

Design And Implementation Of Multi-Responsive Azobenzene Triggers In Self-Immolative And Degradable Polymers, Andrew D. Wong

Electronic Thesis and Dissertation Repository

Self-immolative polymers are a recently developed class of degradable polymers capable of undergoing end-to-end depolymerization following the reaction of their endcaps with appropriate stimuli. Self-immolative materials originated in the field of prodrug chemistry, and evolved into self-immolative oligomers, dendrimers, and most recently, linear polymers. Many stimuli-responsive endcaps have been developed, but typically can only respond to one stimulus. Azobenzenes are a well-known class of stimuli-responsive molecules most commonly used as photoswitches, due to their facile trans-cis isomerization. In addition to their photochemistry, azobenzenes have recently been found to be selectively reduction-sensitive, and are therefore of interest as endcaps in ...


Investigation And Modeling Of Dip-Coating Process For Dispersions, Mahyar Javidi Soufiani 2016 The University of Western Ontario

Investigation And Modeling Of Dip-Coating Process For Dispersions, Mahyar Javidi Soufiani

Electronic Thesis and Dissertation Repository

Dip coating of liquid film deposition on cylindrical substrates is studied using mathematical modeling, numerical simulation and experimental investigation. A mathematical model based on the Landau-Levich approach for dip coating has been developed using the Ellis constitutive equation, for cylindrical geometries, to analyze the effects on the coating thickness of the substrate radius and hydrodynamic behavior for a non-Newtonian fluid. The influence of the viscosity at low shear rates near the surface of the withdrawal film is included in the Ellis model and coating thickness results for Ellis, power law and Newtonian models are compared with experimental data. Good agreement ...


The Effect Of Assembly Technique On Weak Polyelectrolyte Multilayer Film Morphology And Humidity Swelling/Deswelling Behavior, Ziyang Yin 2016 Rose-Hulman Institute of Technology

The Effect Of Assembly Technique On Weak Polyelectrolyte Multilayer Film Morphology And Humidity Swelling/Deswelling Behavior, Ziyang Yin

Graduate Theses - Chemical Engineering

The goal of this research is to investigate the film morphology and humidity swelling/deswelling behavior of polyelectrolyte multilayers (PEMs) that are constructed from poly(allylamine hydrochloride) (PAH) and poly(acrylic acid) (PAA) by two assembly techniques: automated dipping layer-by-layer (LbL) and spin-assisted (SA) LbL. Two sets of pH polyelectrolyte solution conditions were tested: (PAH7.5/PAA3.5) and (PAH7.0/PAA7.0). It was found that when the films were constructed with the same number of bilayers (=20 bilayers), SA-LbL (PAH7.5/PAA3.5) has a greater thickness than (PAH7.0/PAA7.0). (PAH7.5/PAA3.5) thin films ...


Development Of Pvdf Membrane Nanocomposites Via Various Functionalization Approaches For Environmental Applications, Douglas M. Davenport, Minghui Gui, Lindell E. Ormsbee, Dibakar Bhattacharyya 2016 University of Kentucky

Development Of Pvdf Membrane Nanocomposites Via Various Functionalization Approaches For Environmental Applications, Douglas M. Davenport, Minghui Gui, Lindell E. Ormsbee, Dibakar Bhattacharyya

Chemical and Materials Engineering Faculty Publications

Membranes are finding wide applications in various fields spanning biological, water, and energy areas. Synthesis of membranes to provide tunable flux, metal sorption, and catalysis has been done through pore functionalization of microfiltration (MF) type membranes with responsive behavior. This methodology provides an opportunity to improve synthetic membrane performance via polymer fabrication and surface modification. By optimizing the polymer coagulation conditions in phase inversion fabrication, spongy polyvinylidene fluoride (PVDF) membranes with high porosity and large internal pore volume were created in lab and full scale. This robust membrane shows a promising mechanical strength as well as high capacity for loading ...


Fabrication Of Micro-Meltblown Filtration Media Using Parallel Plate Die Design, Mohammad A. Hassan 2016 Biax-Fiberfilm Corporation, Cairo University

Fabrication Of Micro-Meltblown Filtration Media Using Parallel Plate Die Design, Mohammad A. Hassan

Mohammad Abouelreesh Hassan

Meltblown fibers are typically produced using a die technology based on the slot concept, an extension of the sheet die technology with a series of holes substituting the center rectangular slot of the sheet die. While this prevalent technology has met with considerable success, an economical, facile design would be desirable. In this study a new parallel plate die concept to fabricate micro-meltblown fibers that offers simplicity, ease of use, and low cost was examined. The new die concept had parallel plates forming channels for polymer melt to flow through with a set of air holes surrounding them. This die ...


Investigation Of Latex Resins For Use In Aerosol Coatings, Brian Robert Gosselin 2016 Lehigh University

Investigation Of Latex Resins For Use In Aerosol Coatings, Brian Robert Gosselin

Theses and Dissertations

Latex coatings have made large bounds in their development and have become a staple in architectural and decorative paints. Recent years have seen large growth in industrial and automotive coatings as well. However, one area that has not seen the same growth is aerosol coatings. While there are many consumer products that use latex resins, many latex resins do not product an acceptable coating from an aerosol. This study investigated many latex resins for their performance as an aerosol coating. The properties of the latex resins were examined for those that became a successful coating and those that did not ...


The Influence Of Branching Agent Concentration And Geometry On The Non-Isothermal Crystallization Behavior Of Branched Poly(Ethylene Terephthalate), Christopher William August Krohe 2016 Lehigh University

The Influence Of Branching Agent Concentration And Geometry On The Non-Isothermal Crystallization Behavior Of Branched Poly(Ethylene Terephthalate), Christopher William August Krohe

Theses and Dissertations

Poly(ethylene terephthalate) (PET) is a semi-crystalline polymer that has mechanical and thermal properties suitable for many applications. The rate of crystallization in manufacturing environments influences the final physical, mechanical, and optical properties of PET. Many industrial PET processes occur under dynamic or non-isothermal conditions and in the melt phase. The final material properties are influenced by the size, dimension, and distribution of crystallites and morphology that develop upon cooling from the melt. PET films of varying thickness for optical applications require clarity and transparency. One way achieving clarity and transparency in PET films is to limit or inhibit the ...


Bioactive Poly(Beta-Amino Ester) Biomaterials For Treatment Of Infection And Oxidative Stress, Andrew L. Lakes 2016 University of Kentucky

Bioactive Poly(Beta-Amino Ester) Biomaterials For Treatment Of Infection And Oxidative Stress, Andrew L. Lakes

Theses and Dissertations--Chemical and Materials Engineering

Polymers have deep roots as drug delivery tools, and are widely used in clinical to private settings. Currently, however, numerous traditional therapies exist which may be improved through use of polymeric biomaterials. Through our work with infectious and oxidative stress disease prevention and treatment, we aimed to develop application driven, enhanced therapies utilizing new classes of polymers synthesized in-house. Applying biodegradable poly(β-amino ester) (PBAE) polymers, covalent-addition of bioactive substrates to these PBAEs avoided certain pitfalls of free-loaded and non-degradable drug delivery systems. Further, through variation of polymer ingredients and conditions, we were able to tune degradation rates, release profiles ...


Digital Commons powered by bepress