A study on the life extension of polymer materials under radiation environment

International Nuclear Information System (INIS)

Park, K. J.; Park, S. W.; Cho, S. H.; Hong, S. S.

2000-12-01

The object of this study is to improve the stability and the economic profit by reducing the radiation-induced degradation rate of polymer material used under the radiation environment. So far, the resistance to radiation-induced oxidation of a polymer has been improved by the stabilizers. They can play an important role in the anti-oxidants that interrupt the radical-mediated oxidation chain reaction. The stabilization effect could be larger than that achieved in an inert-atmosphere irradiation. Stabilization is a function of stabilizer concentration up to a certain threshold, but it is not further improved above this concentration. Beyond the threshold, the rate of radiation-induced oxidation goes up to the rate that is characteristic for the unstabilized polymer. To make up for this weakness, a technique depositing a thin layer of diamond-like carbon (DLC) on the polymer surface was developed for protecting the radiation-induced oxidation in the air

Polymer-Silica Nanocomposites: A Versatile Platform for Multifunctional Materials

Science.gov (United States)

Chiu, Chi-Kai

Solution sol-gel synthesis is a versatile approach to create polymer-silica nanocomposite materials. The solution-to-solid transformation results in a solid consisting of interconnected nanoporous structure in 3D space, making it the ideal material for filtration, encapsulation, optics, electronics, drug release, and biomaterials, etc. Although the pore between nano and meso size may be tunable using different reaction conditions, the intrinsic properties such as limited diffusion within pore structure, complicated interfacial interactions at the pore surfaces, shrinkage and stress-induced cracking and brittleness have limited the applications of this material. To overcome these problems, diffusion, pore size, shrinkage and stress-induced defects need further investigation. Thus, the presented thesis will address these important questions such as whether these limitations can be utilized as the novel method to create new materials and lead to new applications. First, the behaviors of polymers such as poly(ethylene glycol) inside the silica pores are examined by studying the nucleation and growth of AgCl at the surface of the porous matrix. The pore structure and the pressure induced by the shrinkage affect have been found to induce the growth of AgCl nanocrystals. When the same process is carried out at 160 °C, silver metallization is possible. Due to the shrinkage-induced stresses, the polymer tends to move into open crack spaces and exterior surfaces, forming interconnected silver structure. This interconnected silver structure is very unique because its density is not related to the size scale of nanopore structures. These findings suggest that it is possible to utilize defect surface of silica material as the template to create interconnected silver structure. When the scale is small, polymer may no longer be needed if the diffusion length of Ag is more than the size of silica particles. To validate our assumption, monoliths of sol-gel sample containing AgNO3

Radiation induced estane polymer crosslinking

International Nuclear Information System (INIS)

Fletcher, M.; Foster, P.

1997-01-01

The exposure of polymeric materials to radiation has been known to induce the effects of crosslinking and degradation. The crosslinking phenomena comes about when two long chain polymers become linked together by a primary bond that extends the chain and increases the viscosity, molecular weight and the elastic modules of the polymer. This process has been observed in relatively short periods of time with fairly high doses of radiation, on the order of several megarads/hour. This paper address low dose exposure over long periods of time to determine what the radiation effects are on the polymeric binder material in PBX 9501. An experimental sample of binder material without explosives will be placed into a thermal and radiation field produced from a W-48 put mod 0. Another sample will be placed in a thermal environment without the radiation. The following is the test plan that was submitted to the Pantex process. The data presented here will be from the first few weeks of exposure and this test will be continued over the next few years. Subsequent data will hopefully be presented in the next compatibility and aging conference

Laser-induced damage study of polymer PMMA

International Nuclear Information System (INIS)

Mansour, N.

2001-01-01

This article presents the results of bulk laser-induced damage measurements in polymer PMMA at 532 nm and 1064 nm for nanosecond laser pulses. The damage thresholds were measured for focused spot sizes ranging over two orders of magnitude. In this work, self-focusing effects were verified to be absent by measurements of breakdown thresholds using both linearly and circularly polarized light. At both 1064 nm and 532 nm, the dependence of the breakdown field, E B , on the spot size, ω, was empirically determined to be E B = C/√ω, where C depends on the wavelength. The extracted value for C(λ) at 1064 nm is larger by a factor of 5 than at 532 nm. Possible reasons for this strong dispersion and mechanism for laser-induced damage in polymer materials will be discussed

EDITORIAL Light-induced material organization Light-induced material organization

Science.gov (United States)

Vainos, Nikos; Rode, Andrei V.

2010-12-01

horizons to production processing (Koroleva et al). The use of femtosecond lasers enables polymerization for flexible production of micro-optics and integrated optics (Malinauskas et al). Laser beams of moderate intensity are used to create surface relief patterning in polymer and hybrid matter (Babeva et al) while the use of optimized acrylamide photopolymers results in submicron holographic structures (Trainer et al). In a different concept, the application of laser radiation forces in soft polymer matter offers intriguing, yet unexplored, means for the organization of dense structures and filaments in polymer solutes, pointing to nonlinear optical applications (Anyfantakis et al). Finally, high laser intensities are used for the processing of soft polymer and hybrid matter. In the two modes of operation available, laser-induced forward transfer of polymers is a promising alternative for the creation of controlled structures (Palla-Papavlu et al), while ablative structuring creates interfaces with enhanced properties by excimer laser irradiation at the deep ultraviolet 193 nm and 157 nm wavelengths (Athanasekos et al). Such methods provide flexible tools for the fabrication of optimized photonic sensor structures based on hybrid nanocomposites incorporating diffractive optic interfaces, a technology enabling the recent advent of remote point sensing of chemical and physical agents by light (Vasileiades et al). A substantial part of this work has been supported in the framework of COST MP0604 Action `Optical Micro-Manipulation by Nonlinear Nanophotonics' of the European Science Foundation. We are confident that this collection of papers on light-induced material organization will guide the reader in this emerging field, inspire the interested scientific community and stimulate further research and innovation in this exciting and growing field.

Solid electrolyte material manufacturable by polymer processing methods

Science.gov (United States)

Singh, Mohit; Gur, Ilan; Eitouni, Hany Basam; Balsara, Nitash Pervez

2012-09-18

The present invention relates generally to electrolyte materials. According to an embodiment, the present invention provides for a solid polymer electrolyte material that is ionically conductive, mechanically robust, and can be formed into desirable shapes using conventional polymer processing methods. An exemplary polymer electrolyte material has an elastic modulus in excess of 1.times.10.sup.6 Pa at 90 degrees C. and is characterized by an ionic conductivity of at least 1.times.10.sup.-5 Scm-1 at 90 degrees C. An exemplary material can be characterized by a two domain or three domain material system. An exemplary material can include material components made of diblock polymers or triblock polymers. Many uses are contemplated for the solid polymer electrolyte materials. For example, the present invention can be applied to improve Li-based batteries by means of enabling higher energy density, better thermal and environmental stability, lower rates of self-discharge, enhanced safety, lower manufacturing costs, and novel form factors.

Selectivity of radiation-induced processes in hydrocarbons, related polymers and organized polymer systems

International Nuclear Information System (INIS)

Feldman, V.I.; Sukhov, F.F.; Zezin, A.A.; Orlov, A.Yu.

1999-01-01

was found that kinetics of radical decay was affected strongly by local molecular dynamics of polymeric chains in specific microphases. These features are especially important at low temperatures and for 'well-organized' polymeric systems, such as highly oriented and highly crystalline polymers or microheterogeneous bicomponent systems. The results obtained show that the radiation-induced chemical events in solid polymers are far more selective than it might be expected from formal energetic reasons. The localization of primary events is controlled by conformation, weak molecular interactions, and microstructure of polymeric system. Some important mechanisms of this selectivity could be understood taking into account the properties of prototype ionized molecules. Significance of the concept of 'selective radiation chemistry' for prediction and improvement of the radiation resistance of polymers and polymeric materials is discussed. (author)

Using Light-Induced Thermocleavage in a Roll-to-Roll Process for Polymer Solar Cells

DEFF Research Database (Denmark)

Krebs, Frederik C; Norrman, Kion

2010-01-01

We report on the use of intense visible light with a narrow spectral distribution matched to the region where the conjugated polymer material absorbs to selectively heat the active material and induce thermocleavage. We show a full roll-to-roll process, leading to complete large-area polymer solar...... ion mass spectrometry, attenuated total reflectance infrared, and transmission/reflection UV−vis techniques....

Polymer electronic devices and materials.

Energy Technology Data Exchange (ETDEWEB)

Schubert, William Kent; Baca, Paul Martin; Dirk, Shawn M.; Anderson, G. Ronald; Wheeler, David Roger

2006-01-01

Polymer electronic devices and materials have vast potential for future microsystems and could have many advantages over conventional inorganic semiconductor based systems, including ease of manufacturing, cost, weight, flexibility, and the ability to integrate a wide variety of functions on a single platform. Starting materials and substrates are relatively inexpensive and amenable to mass manufacturing methods. This project attempted to plant the seeds for a new core competency in polymer electronics at Sandia National Laboratories. As part of this effort a wide variety of polymer components and devices, ranging from simple resistors to infrared sensitive devices, were fabricated and characterized. Ink jet printing capabilities were established. In addition to promising results on prototype devices the project highlighted the directions where future investments must be made to establish a viable polymer electronics competency.

Fluctuation-induced long-range interactions in polymer systems

International Nuclear Information System (INIS)

Semenov, A N; Obukhov, S P

2005-01-01

We discover a new universal long-range interaction between solid objects in polymer media. This polymer-induced interaction is directly opposite to the van der Waals attraction. The predicted effect is deeply related to the classical Casimir interactions, providing a unique example of universal fluctuation-induced repulsion rather than normal attraction. This universal repulsion comes from the subtracted soft fluctuation modes in the ideal counterpart of the real polymer system. The effect can also be interpreted in terms of subtracted (ghost) large-scale polymer loops. We establish the general expressions for the energy of polymer-induced interactions for arbitrary solid particles in a concentrated polymer system. We find that the correlation function of the polymer density in a concentrated solution of very long chains follows a scaling law rather than an exponential decay at large distances. These novel universal long-range interactions can be of importance in various polymer systems. We discuss the ways to observe/simulate these fluctuation-induced effects

Photo-induced Mass Transport through Polymer Networks

Science.gov (United States)

Meng, Yuan; Anthamatten, Mitchell

2014-03-01

Among adaptable materials, photo-responsive polymers are especially attractive as they allow for spatiotemporal stimuli and response. We have recently developed a macromolecular network capable of photo-induced mass transport of covalently bound species. The system comprises of crosslinked chains that form an elastic network and photosensitive fluorescent arms that become mobile upon irradiation. We form loosely crosslinked polymer networks by Michael-Addition between multifunctional thiols and small molecule containing acrylate end-groups. The arms are connected to the network by allyl sulfide, that undergoes addition-fragmentation chain transfer (AFCT) in the presence of free radicals, releasing diffusible fluorophore. The networks are loaded with photoinitiator to allow for spatial modulation of the AFCT reactions. FRAP experiments within bulk elastomers are conducted to establish correlations between the fluorophore's diffusion coefficient and experimental variables such as network architecture, temperature and UV intensity. Photo-induced mass transport between two contacted films is demonstrated, and release of fluorophore into a solvent is investigated. Spatial and temporal control of mass transport could benefit drug release, printing, and sensing applications.

A study on the life extension of polymer materials under radiation environment

International Nuclear Information System (INIS)

Park, K. J; Park, S. W.; Jung, K. S.; Cho, S. H.; Seo, H. S.

2001-12-01

The object of this project is to improve the stability and the economics by reducing the radiation-induced oxidation as a factor of degradation of polymer materials used under the radiation environment. In order to attain the objective of this study and to check the effect of diamond-like carbon(DLC) coating on the anti-oxidation reaction, polymer specimens such as ABS, Acryl, Polycarbonate, Polyethylene, Polypropylene, PVC coating DLC thin layer were exposed to high-level gamma radiation, and their irradiation effects were investigated. A plasma-enhanced chemical vapor deposition method was adopted in fabricating a DLC thin film on the polymer specimens, which were irradiated with the non-DLC film deposited specimens under the gamma radiation emitted from Co-60 source from 1x10 5 to 1x10 8 rads exposure. According to the characterization of irradiated specimens from the elapsed time of minimum 4 hours to a maximum of 105 days after the irradiation, the DLC deposition on the polymer surface was revealed to contribute to the improvement on the resistance of the radiation-induced oxidation in this study

METHODS FOR DETECTING BACTERIA USING POLYMER MATERIALS

NARCIS (Netherlands)

Van Grinsven Bart Robert, Nicolaas; Cleij, Thomas

2017-01-01

A method for characterizing bacteria includes passing a liquid containing an analyte comprising a first bacteria and a second bacteria over and in contact with a polymer material on a substrate. The polymer material is formulated to bind to the first bacteria, and the first bacteria binds to the

Conjugated polymer photovoltaic devices and materials

International Nuclear Information System (INIS)

Mozer, A.J.; Niyazi, Serdar Sariciftci

2006-01-01

The science and technology of conjugated polymer-based photovoltaic devices (bulk heterojunction solar cells) is highlighted focusing on three major issues, i.e. (i) nano-morphology optimization, (ii) improving charge carrier mobility, (iii) improving spectral sensitivity. Successful strategies towards improved photovoltaic performance are presented using various novel materials, including double-cable polymers, regioregular polymers and low bandgap polymers. The examples presented herein demonstrate that the bulk heterojunction concept is a viable approach towards developing photovoltaic systems by inexpensive solution-based fabrication technologies. (authors)

LASER INDUCED SELECTIVE ACTIVATION UTILIZING AUTO-CATALYTIC ELECTROLESS PLATING ON POLYMER SURFACE

DEFF Research Database (Denmark)

Zhang, Yang; Nielsen, Jakob Skov; Tang, Peter Torben

2009-01-01

. Characterization of the deposited copper layer was used to select and improve laser parameters. Several types of polymers with different melting points were used as substrate. Using the above mentioned laser treatment, standard grades of thermoplastic materials such as ABS, SAN, PE, PC and others have been......This paper presents a new method for selective micro metallization of polymers induced by laser. An Nd: YAG laser was employed to draw patterns on polymer surfaces using a special set-up. After subsequent activation and auto-catalytic electroless plating, copper only deposited on the laser tracks....... Induced by the laser, porous and rough structures are formed on the surface, which favours the palladium attachment during the activation step prior to the metallization. Laser focus detection, scanning electron microscopy (SEM) and other instruments were used to analyze the topography of the laser track...

Improving geotechnical properties of clayey soil using polymer material

OpenAIRE

Karim Hussein; Al-Soudany Kawther

2018-01-01

This study illustrates the application of polymer material for clayey soil stabilization. The article will focus on studying the strength behavior of the clayey soils reinforced with homogenously polymer fiber. In the current research, “polypropylene” was selected as polymer material to reinforce the natural clay soil. This polymer fiber was added to the clayey soil with four different percentages of (0, 1.5, 3, and 5%) by weight of soil. Various tests with different polymer contents were per...

Polymer Materials for the Heat Recovery

International Nuclear Information System (INIS)

Kolasińska, E; Mazurek, B; Kolasiński, P

2016-01-01

Many of the processes in the industry, agriculture and microscale systems are associated with the waste heat generation, which often may be a menace or lower the efficiency of the processes. The thermoelectric cooling is becoming increasingly popular and gives the possibility to convert waste heat into electricity. The current thermoelectric cooling solutions are based on alloy materials. However, the new technologies pay attention to the environment burden, moreover the regulations of the production and recycling are becoming more and more restrictive. Conducting polymers are thermoelectrically active at low temperatures, cheap and environmentally safe. In this paper authors discuss the possibility of the application of conducting polymers for the heat recovery. Due to the operating temperature range and different nature of the waste heat sources, polymers might be an interesting solution and a complement for alloy-based thermoelectric materials. The character and nature of the formation of waste heat sources and conventional technologies of its recovery are also described in this paper. Moreover the advantages of thermoelectric cooling with the use of polymers are presented and two materials based on polyaniline are proposed. (paper)

Functional and Multifunctional Polymers: Materials for Smart Structures

Science.gov (United States)

Arnold, S.; Pratt, L. M.; Li, J.; Wuagaman, M.; Khan, I. M.

1996-01-01

The ultimate goal of the research in smart structures and smart materials is the development of a new generation of products/devices which will perform better than products/devices built from passive materials. There are a few examples of multilayer polymer systems which function as smart structures, e.g. a synthetic muscle which is a multilayer assembly of a poly(ethylene) layer, a gold layer, and a poly(pyrrole) layer immersed in a liquid electrolyte. Oxidation and reductions of the active pyrrole layer causes the assembly to reversibly deflect and mimic biological muscles. The drawback of such a setup is slow response times and the use of a liquid electrolyte. We have developed multifunctional polymers which will eliminate the use of a liquid electrolyte, and also because the functionalities of the polymers are within a few hundred angstroms, an improved response time to changes in the external field should be possible. Such multifunctional polymers may be classified as the futuristic 'smart materials.' These materials are composed of a number of different functionalities which work in a synergistic fashion to function as a device. The device performs on the application of an external field and such multifunctional polymers may be scientifically labeled as 'field responsive polymers.' Our group has undertaken a systematic approach to develop functional and multifunctional polymers capable of functioning as field responsive polymers. Our approach utilizes multicomponent polymer systems (block copolymers and graft copolymers), the strategy involves the preparation of block or graft copolymers where the functionalities are limited to different phases in a microphase separated system. Depending on the weight (or volume) fractions of each of the components, different microstructures are possible. And, because of the intimate contact between the functional components, an increase in the synergism between the functionalities may be observed. In this presentation, three

Development directions of packaging made from polymer materials

Directory of Open Access Journals (Sweden)

Jovanović Slobodan

2011-01-01

Full Text Available World packaging market achieves turnover of about $620 billion per year with one third of this amount being associated to packaging made from polymer materials. It is expected that this kind of packaging consumption will hold at least 3% of world packaging market share in the next five years and that it will surpass the consumption of all other materials used in the packaging production. This can be contributed to product quality, low production costs as well as significant investments made in the development of polymer materials, packaging technology and packaging. This paper presents some development directions for packaging made from polymer materials, such as: packaging in the protective atmosphere, the use of active and intelligent packaging, and the use of biopolymers and recycled polymers for packaging production that come into direct contact with the packed product.

Developing polymer composite materials: carbon nanotubes or graphene?

Science.gov (United States)

Sun, Xuemei; Sun, Hao; Li, Houpu; Peng, Huisheng

2013-10-04

The formation of composite materials represents an efficient route to improve the performances of polymers and expand their application scopes. Due to the unique structure and remarkable mechanical, electrical, thermal, optical and catalytic properties, carbon nanotube and graphene have been mostly studied as a second phase to produce high performance polymer composites. Although carbon nanotube and graphene share some advantages in both structure and property, they are also different in many aspects including synthesis of composite material, control in composite structure and interaction with polymer molecule. The resulting composite materials are distinguished in property to meet different applications. This review article mainly describes the preparation, structure, property and application of the two families of composite materials with an emphasis on the difference between them. Some general and effective strategies are summarized for the development of polymer composite materials based on carbon nanotube and graphene. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multilayer Electroactive Polymer Composite Material

Science.gov (United States)

Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Park, Cheol (Inventor); Draughon, Gregory K. (Inventor); Ounaies, Zoubeida (Inventor)

2011-01-01

An electroactive material comprises multiple layers of electroactive composite with each layer having unique dielectric, electrical and mechanical properties that define an electromechanical operation thereof when affected by an external stimulus. For example, each layer can be (i) a 2-phase composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation, or (ii) a 3-phase composite having the elements of the 2-phase composite and further including a third component of micro-sized to nano-sized particles of an electroactive ceramic incorporated in the polymer matrix.

Temperature and strain registration by fibre-optic strain sensor in the polymer composite materials manufacturing

Science.gov (United States)

Matveenko; Kosheleva; Shardakov; Voronkov

2018-04-01

The presence of process-induced strains induced by various manufacturing and operational factors is one of the characteristics of polymer composite materials (PCM). Conventional methods of registration and evaluation of process-induced strains can be laborious, time-consuming and demanding in terms of technical applications. The employment of embedded fibre-optic strain sensors (FOSS) offers a real prospect of measuring residual strains. This paper demonstrates the potential for using embedded FOSS for recording technological strains in a PCM plate. The PCM plate is manufactured from prepreg, using the direct compression-moulding method. In this method, the prepared reinforcing package is placed inside a mould, heated, and then exposed to compaction pressure. The examined technology can be used for positioning FOSS between the layers of the composite material. Fibre-optic sensors, interacting with the material of the examined object, make it possible to register the evolution of the strain process during all stages of polymer-composite formation. FOSS data were recorded with interrogator ASTRO X 327. The obtained data were processed using specially developed algorithms.

Laser-evoked coloration in polymers

International Nuclear Information System (INIS)

Zheng, H.Y.; Rosseinsky, David; Lim, G.C.

2005-01-01

Laser-evoked coloration in polymers has long been a major aim of polymer technology for potential applications in product surface decoration, marking personalised images and logos. However, the coloration results reported so far were mostly attributed to laser-induced thermal-chemical reactions. The laser-irradiated areas are characterized with grooves due to material removal. Furthermore, only single color was laser-induced in any given polymer matrix. To induce multiple colors in a given polymer matrix with no apparent surface material removal is most desirable and challenging and may be achieved through laser-induced photo-chemical reactions. However, little public information is available at present. We report that two colors of red and green have been produced on an initially transparent CPV/PVA samples through UV laser-induced photo-chemical reactions. This is believed the first observation of laser-induced multiple-colors in the given polymer matrix. It is believed that the colorants underwent photo-effected electron transfer with suitable electron donors from the polymers to change from colorless bipyridilium Bipm 2+ to the colored Bipm + species. The discovery may lead to new approaches to the development of laser-evoked multiple coloration in polymers

Encapsulation of dye molecules into mesoporous polymer resin and mesoporous polymer-silica films by an evaporation-induced self-assembly method

Energy Technology Data Exchange (ETDEWEB)

Chi Yue; Li Nan; Tu Jinchun; Zhang Yujie [School of Material Science and Engineering, Key Laboratory of Automobile Materials of Ministry of Education, Jilin University, Changchun 130012 (China); Li Xiaotian, E-mail: xiaotianli@jlu.edu.c [School of Material Science and Engineering, Key Laboratory of Automobile Materials of Ministry of Education, Jilin University, Changchun 130012 (China); Shao Changlu, E-mail: clshao@nenu.edu.c [Center for Advanced Optoelectronic Functional Materials Research, Northeast Normal University, Changchun 130024 (China)

2010-03-15

Polymer resin and polymer-silica films with highly ordered mesostructure have been used as host materials to encapsulate DCM (4-(dicyanomethylene) -2-methyl-6-(4-dimethylaminostyryl)-4h-pyran), a kind of fluorescent dye, through evaporation-induced self-assembly method (EISA). After encapsulation, the composites show significant blue-shift in photoluminescence (PL) spectra. Particularly, by changing the excitation wavelength, the samples show different emission bands. These phenomena are related to the mesostructure and the positions of DCM molecules in the host.

Naphthalene Diimide Based n-Type Conjugated Polymers as Efficient Cathode Interfacial Materials for Polymer and Perovskite Solar Cells.

Science.gov (United States)

Jia, Tao; Sun, Chen; Xu, Rongguo; Chen, Zhiming; Yin, Qingwu; Jin, Yaocheng; Yip, Hin-Lap; Huang, Fei; Cao, Yong

2017-10-18

A series of naphthalene diimide (NDI) based n-type conjugated polymers with amino-functionalized side groups and backbones were synthesized and used as cathode interlayers (CILs) in polymer and perovskite solar cells. Because of controllable amine side groups, all the resulting polymers exhibited distinct electronic properties such as oxidation potential of side chains, charge carrier mobilities, self-doping behaviors, and interfacial dipoles. The influences of the chemical variation of amine groups on the cathode interfacial effects were further investigated in both polymer and perovskite solar cells. We found that the decreased electron-donating property and enhanced steric hindrance of amine side groups substantially weaken the capacities of altering the work function of the cathode and trap passivation of the perovskite film, which induced ineffective interfacial modifications and declining device performance. Moreover, with further improvement of the backbone design through the incorporation of a rigid acetylene spacer, the resulting polymers substantially exhibited an enhanced electron-transporting property. Upon use as CILs, high power conversion efficiencies (PCEs) of 10.1% and 15.2% were, respectively, achieved in polymer and perovskite solar cells. Importantly, these newly developed n-type polymers were allowed to be processed over a broad thickness range of CILs in photovoltaic devices, and a prominent PCE of over 8% for polymer solar cells and 13.5% for perovskite solar cells can be achieved with the thick interlayers over 100 nm, which is beneficial for roll-to-roll coating processes. Our findings contribute toward a better understanding of the structure-performance relationship between CIL material design and solar cell performance, and provide important insights and guidelines for the design of high-performance n-type CIL materials for organic and perovskite optoelectronic devices.

Swift heavy ion induced modification of aliphatic polymers

International Nuclear Information System (INIS)

Hossain, Umme Habiba

2015-01-01

In this thesis, the high energy heavy ion induced modification of aliphatic polymers is studied. Two polymer groups, namely polyvinyl polymers (PVF, PVAc, PVA and PMMA) and fluoropolymers (PVDF, ETFE, PFA and FEP) were used in this work. Polyvinyl polymers were investigated since they will be used as insulating materials in the superconducting magnets of the new ion accelerators of the planned International Facility for Antiproton and Ion Research (FAIR) at the GSI Helmholtz-Centre of Heavy Ion Research (GSI) in Darmstadt. In order to study ion-beam induced degradation, all polymer foils were irradiated at the GSI linear accelerator UNILAC using several projectiles (U, Au, Sm, Xe) and experimentation sites (beam lines X0 and M3) over a large fluence regime (1 x 10 10 - 5 x 10 12 ions/cm 2 ). Five independent techniques, namely infrared (FT-IR) and ultraviolet-visible (UV-Vis) spectroscopy, residual gas analysis (RGA), thermal gravimetric analysis (TGA), and mass loss analysis (ML), were used to analyze the irradiated samples. FT-IR spectroscopy revealed that ion irradiation led to the decrease of characteristic band intensities showing the general degradation of the polymers, with scission of side groups and the main backbone. As a consequence of the structural modification, new bands appeared. UV-Vis transmission analysis showed an absorption edge shift from the ultraviolet region towards the visible region indicating double bond and conjugated double bond formation. On-line massspectrometric residual gas analysis showed the release of small gaseous fragment molecules. TGA analysis gave evidence of a changed thermal stability. With ML analysis, the considerable mass loss was quantified. The results of the five complementary analytical methods show how heavy ion irradiation changes the molecular structure of the polymers. Molecular degradation mechanisms are postulated. The amount of radiation damage is found to be sensitive to the used type of ionic species. While

Electric Field Induced Strain in Electrostrictive Polymers Under High Hydrostatic Pressure - System Development and Material Characterization

National Research Council Canada - National Science Library

Zhang, Q

2000-01-01

... of (i) developing a high performance piezo-bimorph based dilatometer which can be used to characterize the electric field induced strain response in polymer films under high hydrostatic pressure, (ii...

A review of piezoelectric polymers as functional materials for electromechanical transducers

International Nuclear Information System (INIS)

Ramadan, Khaled S; Evoy, S; Sameoto, D

2014-01-01

Polymer based MEMS and microfluidic devices have the advantages of mechanical flexibility, lower fabrication cost and faster processing over silicon based ones. Also, many polymer materials are considered biocompatible and can be used in biological applications. A valuable class of polymers for microfabricated devices is piezoelectric functional polymers. In addition to the normal advantages of polymers, piezoelectric polymers can be directly used as an active material in different transduction applications. This paper gives an overview of piezoelectric polymers based on their operating principle. This includes three main categories: bulk piezoelectric polymers, piezocomposites and voided charged polymers. State-of-the-art piezopolymers of each category are presented with a focus on fabrication techniques and material properties. A comparison between the different piezoelectric polymers and common inorganic piezoelectric materials (PZT, ZnO, AlN and PMN–PT) is also provided in terms of piezoelectric properties. The use of piezopolymers in different electromechanical devices is also presented. This includes tactile sensors, energy harvesters, acoustic transducers and inertial sensors. (topical review)

Temperature- and light-responsive smart polymer materials.

Science.gov (United States)

Jochum, Florian D; Theato, Patrick

2013-09-07

Stimuli-responsive polymers have been attracting great interest within the scientific community for several decades. The unique feature to respond to small changes in the environmental conditions has made this class of materials very promising for several applications in the field of nanoscience, nanotechnology and nanomedicine. So far, several different chemical, physical or biochemical stimuli have been investigated within natural or synthetic polymers. Very interesting and appealing seems to be the combination of several stimuli to tune the properties of these materials in manifold ways. Within this present review, we want to highlight the recent progress in the field of synthetic stimuli-responsive polymers combining temperature and light responsiveness.

Materials comprising polydienes and hydrophilic polymers and related methods

Science.gov (United States)

Mays, Jimmy W [Knoxville, TN; Deng, Suxiang [Knoxville, TN; Mauritz, Kenneth A [Hattiesburg, MS; Hassan, Mohammad K [Hattiesburg, MS; Gido, Samuel P [Hadley, MA

2011-11-22

Materials prepared from polydienes, such as poly(cyclohexadiene), and hydrophilic polymers, such as poly(alkylene oxide), are described. Methods of making the materials and their use in fuel cell membranes, batteries, breathable chemical-biological protective materials, and templates for sol-gel polymerization are also provided. The materials can be crosslinked and sulfonated, and can include copolymers and polymer blends.

Inorganic polymers and materials. Final report

Energy Technology Data Exchange (ETDEWEB)

Sneddon, Larry G.

2001-01-01

This DOE-sponsored project was focused on the design, synthesis, characterization, and applications of new types of boron and silicon polymers with a goal of attaining processable precursors to advanced ceramic materials of technological importance. This work demonstrated a viable design strategy for the systematic formation of polymeric precursors to ceramics based on the controlled functionalization of preformed polymers with pendant groups of suitable compositions and crosslinking properties. Both the new dipentylamine-polyborazylene and pinacolborane-hydridopolysilazane polymers, unlike the parent polyborazylene and other polyborosilazanes, are stable as melts and can be easily spun into polymer fibers. Subsequent pyrolyses of these polymer fibers then provide excellent routes to BN and SiNCB ceramic fibers. The ease of synthesis of both polymer systems suggests new hybrid polymers with a range of substituents appended to polyborazylene or polysilazane backbones, as well as other types of preceramic polymers, should now be readily achieved, thereby allowing even greater control over polymer and ceramic properties. This control should now enable the systematic tailoring of the polymers and derived ceramics for use in different technological applications. Other major recent achievements include the development of new types of metal-catalyzed methods needed for the polymerization and modification of inorganic monomers and polymers, and the modification studies of polyvinylsiloxane and related polymers with substituents that enable the formation of single source precursors to high-strength, sintered SiC ceramics.

Development of Self-Assembled Nanoscale Templates via Microphase Separation Induced by Polymer Brushes

Science.gov (United States)

Chu, Elza

Phase separation in soft matter has been the crucial element in generating hybrid materials, such as polymer blends and mixed polymer brushes. This dissertation discusses two methods of developing self-assembled nanoscale templates via microphase separation induced by polymer brush synthesis. This work introduces a novel soft substrate approach with renewable grafting sites where polyacrylamide is "grafted through" chitosan soft substrates. The mechanism of grafting leads to ordered arrays of filament-like nanostructures spanning the chitosan-air interface. Additionally, the chemical composition of the filaments allows for post-chemical modification to change the physical properties of the filaments, and subsequently tailor surfaces for specific application. Unlike traditional materials, multi-functional or "smart" materials, such as binary polymer brushes (BPB) are capable of spontaneously changing the spatial distribution of functional groups and morphology at the surface upon external stimuli. Although promising in principle, the limited range of available complementary polymers with common non-selective solvents confines the diversity of usable materials and restricts any further advancement in the field. This dissertation also covers the fabrication and characterization of responsive nanoscale polystyrene templates or "mosaic" brushes that are capable of changing interfacial composition upon exposure to varying solvent qualities. Using a "mosaic" brush template is a unique approach that allows the fabrication of strongly immiscible polymer BPB without the need for a common solvent. The synthesis of such BPB is exemplified by two strongly immiscible polymers, i.e. polystyrene (polar) and polyacrylamide (non-polar), where polyacrylamide brush is "graft through" a Si-substrate modified with the polystyrene collapsed "mosaic" brush. The surface exhibits solvent-triggered responses, as well as application potential for anti-biofouling.

Development of neutron shielding material using metathesis-polymer matrix

Energy Technology Data Exchange (ETDEWEB)

Sakurai, Yoshinori E-mail: ysakurai@rri.kyoto-u.ac.jp; Sasaki, Akira; Kobayashi, Tooru

2004-04-21

A neutron shielding material using a metathesis-polymer matrix, which is a thermosetting resin, was developed. This shielding material has characteristics that can be controlled for different mixing ratios of neutron absorbers and for formation in the laboratory. Additionally, the elastic modulus can be changed at the hardening process, from a flexible elastoma to a mechanically tough solid. Experiments were performed at the Kyoto University Research Reactor in order to determine the important characteristics of this metathesis-polymer shielding material, such as neutron shielding performance, secondary gamma-ray generation and activation. The metathesis-polymer shielding material was shown to be practical and as effective as the other available shielding materials, which mainly consist of thermoplastic resin.

Radiation-Induced Graft Polymerization: Gamma Radiation and Electron Beam Technology for Materials Development

International Nuclear Information System (INIS)

Madrid, Jordan F.; Cabalar, Patrick Jay; Lopez, Girlie Eunice; Abad, Lucille V.

2015-01-01

The formation of functional hybrid materials by attaching polymer chains with advantageous tailored properties to the surface of a base polymer with desirable bulk character is an attractive application of graft copolymerization. Radiation-induced graft polymerization (RIGP) has been a popular approach for surface modification of polymers because of its merits over conventional chemical processes. RIGP, which proceeds primarily via free radical polymerization process, has the advantages such as simplicity, low cost, control over process and adjustment of the materials composition and structure. RIGP can be performed using either electron beam or gamma radiation and it can be applied to both synthetic and natural polymers. These merits make RIGP a popular research topic worldwide. Moreover, the materials synthesized and produced via RIGP has found applications, and were proposed to produce continuous impact, in the fields of medicine, agriculture, pollution remediation, rare earth and valuable metals recovery, fuel cell membrane synthesis and catalysis to name a few. From 2012 our group has performed electron beam and gamma radiation-induced graft polymerization of various monomers onto polymers of natural and synthetic origins (e.g. monomers - glycidyl methacrylate, styrene, acrylonitrile, N,N-dimethylaminoethyl methacrylate; base polymers – polyethylene/polypropylene nonwoven fabric, polypropylene nonwoven fabric pineapple fibers, cellulose nonwoven fabric microcrystalline cellulose). We tested these grafted materials for heavy metals (Pb, Ni, Cu) and organic molecule removal from aqueous solutions and E. coli activity (using reversible addition fragmentation chain transfer RAFT mediated grafting). The results clearly showed the success of materials modified via FIGP in these applications. Currently, we are studying the applications of grafted materials on treatment of waste waters from tanning industry, value addition to abaca nonwoven fabrics cell sheet

Reducing burn-in voltage loss in polymer solar cells by increasing the polymer crystallinity

KAUST Repository

Heumueller, Thomas

2014-08-01

In order to commercialize polymer solar cells, the fast initial performance losses present in many high efficiency materials will have to be managed. This burn-in degradation is caused by light-induced traps and its characteristics depend on which polymer is used. We show that the light-induced traps are in the bulk of the active layer and we find a direct correlation between their presence and the open-circuit voltage loss in devices made with amorphous polymers. Solar cells made with crystalline polymers do not show characteristic open circuit voltage losses, even though light-induced traps are also present in these devices. This indicates that crystalline materials are more resistant against the influence of traps on device performance. Recent work on crystalline materials has shown there is an energetic driving force for charge carriers to leave amorphous, mixed regions of bulk heterojunctions, and charges are dominantly transported in pure, ordered phases. This energetic landscape allows efficient charge generation as well as extraction and also may benefit the stability against light-induced traps. This journal is © the Partner Organisations 2014.

Cationic polymers and porous materials

KAUST Repository

Han, Yu

2017-04-27

According to one or more embodiments, cationic polymers may be produced which include one or more monomers containing cations. Such cationic polymers may be utilized as structure directing agents to form mesoporous zeolites. The mesoporous zeolites may include micropores as well as mesopores, and may have a surface area of greater than 350 m2/g and a pore volume of greater than 0.3 cm3/g. Also described are core/shell zeolites, where at least the shell portion includes a mesoporous zeolite material.

Cationic polymers and porous materials

KAUST Repository

Han, Yu; Tian, Qiwei; Dong, Xinglong; Liu, Zhaohui; Basset, Jean-Marie; Saih, Youssef; Sun, Miao; Xu, Wei; Shaikh, Sohel

2017-01-01

According to one or more embodiments, cationic polymers may be produced which include one or more monomers containing cations. Such cationic polymers may be utilized as structure directing agents to form mesoporous zeolites. The mesoporous zeolites may include micropores as well as mesopores, and may have a surface area of greater than 350 m2/g and a pore volume of greater than 0.3 cm3/g. Also described are core/shell zeolites, where at least the shell portion includes a mesoporous zeolite material.

A review of mechanical and tribological behaviour of polymer composite materials

Science.gov (United States)

Prabhakar, K.; Debnath, S.; Ganesan, R.; Palanikumar, K.

2018-04-01

Composite materials are finding increased applications in many industrial applications. A nano-composite is a matrix to which nanosized particles have been incorporated to drastically improve the mechanical performance of the original material. The structural components produced using nano-composites will exhibit a high strength-to-weight ratio. The properties of nano-composites have caused researchers and industries to consider using this material in several fields. Polymer nanocomposites consists of a polymer material having nano-particles or nano-fillers dispersed in the polymer matrix which may be of different shapes with at least one of the dimensions less than 100nm. In this paper, comprehensive review of polymer nanocomposites was done majorly in three different areas. First, mechanical behaviour of polymer nanocomposites which focuses on the mechanical property evaluation such as tensile strength, impact strength and modulus of elasticity based on the different combination of filler materials and nanoparticle inclusion. Second, wear behavior of Polymer composite materials with respect to different impingement angles and variation of filler composition using different processing techniques. Third, tribological (Friction and Wear) behaviour of nanocomposites using various combination of nanoparticle inclusion and time. Finally, it summarized the challenges and prospects of polymer nanocomposites.

Laser induced forward transfer of soft materials

International Nuclear Information System (INIS)

Palla-Papavlu, A; Dinca, V; Luculescu, C; Dinescu, M; Shaw-Stewart, J; Lippert, T; Nagel, M

2010-01-01

A strong research effort is presently aimed at patterning methodologies for obtaining controlled defined micrometric polymeric structures for a wide range of applications, including electronics, optoelectronics, sensors, medicine etc. Lasers have been identified as appropriate tools for processing of different materials, such as ceramics and metals, but also for soft, easily damageable materials (biological compounds and polymers). In this work we study the dynamics of laser induced forward transfer (LIFT) with a gap between the donor and the receiver substrates, which is the basis for possible applications that require multilayer depositions with high spatial resolution

Affects of Microgravity on the Polymerization and Material Properties of Biomedical Grade Polymers

Science.gov (United States)

Crane, Deborah J.

2002-01-01

the material of choice in the production of acetabular cups for hip and tibial cradles for knee orthopeadic implant components for over 30 years. Although UHMWPE is used for more than 1.5 million implants a year in the United States alone and more than 3 million implant surgeries a year worldwide, problems with debris particle formation, pitting and fracture continue to induce premature failure of implant components. chains produced during polymerization are capable of packing into crystalline structures called lamellae, which are embedded within randomly oriented amorphous regions. Crosslinks, or tie molecules bridge the crystalline structures, which contribute to the materials' toughness and strength as a biomedical material. Research has been conducted providing evidence that a crosslinked gradient at the articulating surface of the polymer component provides resistance to surface degradation and subsequent debris formation. Recently, the introduction of highly crosslinked UHMWPE had proven to reduce some of the problems associated with the applications of this polymer as a biomedical material and was seen as the answer to solving the continuing problems associated with UHMWPE implant components. Yet current research into the fatigue characteristics of highly crosslinked UHMWPE has shown that subsurface crack propagation and subsequent delamination continues to produce problematic debris generation. Studies have shown that various sterilization and accelerated aging (to emulate natural oxidation rates) protocols adversely effects the material properties. Additional research has shown that alignment of the lamellae, caused by processing technique, fabrication or surface articulation may be the precursor to debris particle formation. Processing techniques performed under high pressure has proven to effect the width of the crystalline lamellae and therefore, the material's response to wear and fracture. UHMWP due to a microgravity environment, which could be

Bergman cyclization in polymer chemistry and material science.

Science.gov (United States)

Xiao, Yuli; Hu, Aiguo

2011-11-01

Bergman cyclization of enediynes, regarded as a promising strategy for anticancer drugs, now finds its own niche in the area of polymer chemistry and material science. The highly reactive aromatic diradicals generated from Bergman cyclization can undergo polymerization acting as either monomers or initiators of other vinyl monomers. The former, namely homopolymerization, leads to polyphenylenes and polynaphthalenes with excellent thermal stability, good solubility, and processability. The many remarkable properties of these aromatic polymers have further endowed them to be manufactured into carbon-rich materials, e.g., glassy carbons and carbon nanotubes. Whereas used as initiators, enediynes provide a novel resource for high molecular weight polymers with narrow polydispersities. The aromatic diradicals are also useful for introducing oligomers or polymers onto pristine carbonous nanomaterials, such as carbon nano-onions and carbon nanotubes, to improve their dispersibility in organic solvents and polymer solutions. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High performance lignin-acrylonitrile polymer blend materials

Energy Technology Data Exchange (ETDEWEB)

Naskar, Amit K.; Tran, Chau D.

2017-11-14

A polymer blend material comprising: (i) a lignin component having a weight-average molecular weight of up to 1,000,000 g/mol; and (ii) an acrylonitrile-containing copolymer rubber component comprising acrylonitrile units in combination with diene monomer units, and having an acrylonitrile content of at least 20 mol %; wherein said lignin component is present in an amount of at least 5 wt % and up to about 95 wt % by total weight of components (i) and (ii); and said polymer blend material possesses a tensile yield stress of at least 5 MPa, or a tensile stress of at least 5 MPa at 10% elongation, or a tensile stress of at least 5 MPa at 100% elongation. Methods for producing the polymer blend, molded forms thereof, and articles thereof, are also described.

Modification of Polymer Materials by Ion Bombardment: Case Studies

International Nuclear Information System (INIS)

Bielinski, D. M.; Jagielski, J.; Lipinski, P.; Pieczynska, D.; Ostaszewska, U.; Piatkowska, A.

2009-01-01

The paper discusses possibility of application of ion beam bombardment for modification of polymers. Changes to composition, structure and morphology of the surface layer produced by the treatment and their influence on engineering and functional properties of wide range of polymer materials are presented. Special attention has been devoted to modification of tribological properties. Ion bombardment results in significant reduction of friction, which can be explained by increase of hardness and wettability of polymer materials. Hard but thin enough skin does not result in cracking but improves their abrasion resistance. Contrary to conventional chemical treatment ion beam bombardment works even for polymers hardly susceptible to modification like silicone rubber or polyolefines.

Radiation resistance of polymer materials. Degradation evaluation by accelerated testing for application condition

International Nuclear Information System (INIS)

Seguchi, Tadao; Tamura, Kiyotoshi; Sorimachi, Masami

2010-02-01

This paper presents re-evaluated radiation resistance property data of polymer materials, which had been tested in past times in TAKASAKI Quantum Beam Science Directorate, for the future study of ageing evaluation of low voltage electric cable insulation materials used in light-water nuclear reactors. The radiation resistance of 25 types of plastics and rubbers materials applied in practical environments was evaluated by the accelerated testing of gamma-ray irradiation under oxygen pressure, and was compared with the radiation resistance determined from the traditional testing by irradiation with a high dose rate in air. The polymer materials were formulated to be similar or equivalent to practical materials, and the most of formulation (chemical compounds and quantities) were described. For all materials, the tensile properties (elongation at break, ultimate strength, 100% or 200% modulus), electric resistivity, gel-fraction, and density were measured after irradiation in oxidation conditions and irradiation in air with a high dose rate (non-oxidation conditions). The data of relations between each properties and total dose at various conditions were compiled, and the relations among the changes of mechanical properties, electrical properties, and radiation induced chemical reactions were discussed. (author)

Biocompatible Polymer/Quantum Dots Hybrid Materials: Current Status and Future Developments

Directory of Open Access Journals (Sweden)

Lei Shen

2011-12-01

Full Text Available Quantum dots (QDs are nanometer-sized semiconductor particles with tunable fluorescent optical property that can be adjusted by their chemical composition, size, or shape. In the past 10 years, they have been demonstrated as a powerful fluorescence tool for biological and biomedical applications, such as diagnostics, biosensing and biolabeling. QDs with high fluorescence quantum yield and optical stability are usually synthesized in organic solvents. In aqueous solution, however, their metallic toxicity, non-dissolubility and photo-luminescence instability prevent the direct utility of QDs in biological media. Polymers are widely used to cover and coat QDs for fabricating biocompatible QDs. Such hybrid materials can provide solubility and robust colloidal and optical stability in water. At the same time, polymers can carry ionic or reactive functional groups for incorporation into the end-use application of QDs, such as receptor targeting and cell attachment. This review provides an overview of the recent development of methods for generating biocompatible polymer/QDs hybrid materials with desirable properties. Polymers with different architectures, such as homo- and co-polymer, hyperbranched polymer, and polymeric nanogel, have been used to anchor and protect QDs. The resulted biocompatible polymer/QDs hybrid materials show successful applications in the fields of bioimaging and biosensing. While considerable progress has been made in the design of biocompatible polymer/QDs materials, the research challenges and future developments in this area should affect the technologies of biomaterials and biosensors and result in even better biocompatible polymer/QDs hybrid materials.

Use of polymer concrete for construction materials

International Nuclear Information System (INIS)

Vrtanoski, Gligorche; Dukovski, Vladimir; Yamaguchi, Kitazumi

2002-01-01

Polymer concrete (PC), or resin concrete, consists of a polymer binder, which may be a thermoplastic but more frequently is a thermosetting polymer, and a mineral filler such as aggregate, gravel and crushed stone. PC has higher strength, greater resistance to chemicals and corrosive agents, lower water absorption and higher freeze-thaw stability than the conventional Portland cement concrete and Cast Iron. This paper is a review of the key features of PC materials as a bases for comparison with the cast iron. (Original)

Water-Induced Degradation of Polymer Solar Cells Studied by (H2O)-O-18 Labeling

DEFF Research Database (Denmark)

Norrman, Kion; Gevorgyan, Suren; Krebs, Frederik C

2009-01-01

Water-induced degradation of polymer photovoltaics based on the active materials poly(3-hexylthiophene) (P3HT) or poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] (MEHPPV) was studied. The solar cell devices comprised a bulk heterojunction formed by the active material and [6,6]-phenyl......-C61-butyric acid methyl ester (PCBM) in a standard device geometry. The use of H218O in conjunction with time-of-flight secondary ion mass spectrometry enabled mapping of the parts of the device that were induced by water. A comparison was made between the two active materials and between devices...

21 CFR 874.3620 - Ear, nose, and throat synthetic polymer material.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ear, nose, and throat synthetic polymer material. 874.3620 Section 874.3620 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN..., and throat synthetic polymer material. (a) Identification. Ear, nose, and throat synthetic polymer...

Chemical modifications of polymer films induced by high energy heavy ions

International Nuclear Information System (INIS)

Zhu Zhiyong; Sun Youmei; Liu Changlong; Liu Jie; Jin Yunfan

2002-01-01

Polymer films including polyethylene terephthalate (PET), polystyrene (PS) and polycarbonate (PC) were irradiated at room temperature with ions of 35 MeV/u 40 Ar, 25 MeV/u 84 Kr, 15.1 MeV/u 136 Xe and 11.4 MeV/u 238 U to fluences ranging from 9x10 9 to 5.5x10 12 ions/cm 2 . The radiation-induced chemical changes of the materials were investigated by Fourier-transform infrared (FTIR) and ultraviolet/visible spectroscopies. It is found that the absorbance in the ultraviolet and visible range induced by all irradiations follows a linear relationship with fluence. The radiation-induced absorbance normalized to one particle increases slowly with increasing of electronic energy loss below about 8 keV/nm followed by a sharp increase up to about 15 keV/nm above which saturation is reached. FTIR measurements reveal that the materials suffer serious degradation through bond breaking. The absorbance of the typical infrared bands decays exponentially with increase of ion fluence and the bond-disruption cross-section shows a sigmoid variation with electronic energy loss. In PET loss of crystallinity is attributed to the configuration transformation of the ethylene glycol residue from trans into the gauche. Alkyne end groups are induced in all the materials above certain electronic energy loss threshold, which is found to be about 0.8 keV/nm for PS and 0.4 keV/nm for PC. The production cross-section of alkyne end group increases with increasing of electronic energy loss and shows saturation at high electronic energy loss values. It is concluded that not only the physical processes but also the chemical processes of the energy deposition determine the modification of polymer

Improving geotechnical properties of clayey soil using polymer material

Directory of Open Access Journals (Sweden)

Karim Hussein

2018-01-01

Full Text Available This study illustrates the application of polymer material for clayey soil stabilization. The article will focus on studying the strength behavior of the clayey soils reinforced with homogenously polymer fiber. In the current research, “polypropylene” was selected as polymer material to reinforce the natural clay soil. This polymer fiber was added to the clayey soil with four different percentages of (0, 1.5, 3, and 5% by weight of soil. Various tests with different polymer contents were performed to study the effect of using such a polymer as a stabilizing agent on geotechnical properties of clay. As the fiber content increases, the optimum moisture content (OMC is increased while the specific gravity decreases. For Atterberg’s limits, the results indicated increasing liquid limit and plasticity index while decreasing plastic limit with increase in polymer content. The outcomes of the tests also reflected a considerable improvement in the unconfined compressive strength with noticeable improvement in the shear strength parameter (undrained shear strength, cu of the treated soils. The undrained shear strength obtained from treated soil with 5% polymer addition is more than three times that of the untreated soil. With an increase in polymer content, the consolidation parameters (Compression index Cc and recompression index Cr decreases. Finally, the benefit of the reinforcement is increased with increasing polymer fiber content.

Assembling and properties of the polymer-particle nanostructured materials

Science.gov (United States)

Sheparovych, Roman

Complementary properties of the soft and hard matter explain its common encounter in many natural and manmade applications. A combination of flexible organic macromolecules and hard mineral clusters results in new materials far advantageous than its constituents alone. In this work we study assembling of colloidal nanocrystals and polymers into complex nanostructures. Magnetism, surface wettability and adhesion comprise properties of interest for the obtained nanocomposites. Applying a magnetic field induces a reversible 1D ordering of the magnetically susceptible particles. This property was employed in the fabrication of the permanent chains of magnetite nanocrystals (d=15nm). In the assembling process the aligned particles were bound together using polyelectrolyte macromolecules. The basics of the binding process involved an electrostatic interaction between the positively charged polyelectrolyte and the negative surface of the particles (aqueous environment). Adsorption of the polymer molecules onto several adjacent particles in the aligned 1D aggregate results in the formation of the permanent particulate chains. Positive charges of the adsorbed polyelectrolyte molecules stabilize the dispersion of the obtained nanostructures in water. Magnetization measurements revealed that superparamagnetic nanoparticles, being assembled into 1D ordered structures, attain magnetic coercivity. This effect originates from the magnetostatic interaction between the neighboring magnetite nanocrystals. The preferable dipole alignment of the assembled nanoparticles is directed along the chain axis. Another system studied in this project includes polymer-particle responsive surface coatings. Tethered polymer chains and particles bearing different functionalities change surface properties upon restructuring of the composite layer. When the environment favors polymer swelling (good solvent), the polymer chains segregate to the surface and cover the particles. In the opposite case

Reutilization of discarded biomass for preparing functional polymer materials.

Science.gov (United States)

Wang, Jianfeng; Qian, Wenzhen; He, Yufeng; Xiong, Yubing; Song, Pengfei; Wang, Rong-Min

2017-07-01

Biomass is abundant and recyclable on the earth, which has been assigned numerous roles to human beings. However, over the past decades, accompanying with the rapid expansion of man-made materials, such as alloy, plastic, synthetic rubber and fiber, a great number of natural materials had been neglected and abandoned, such as straw, which cause a waste of resource and environmental pollution. In this review, based on introducing sources of discarded biomass, the main composition and polymer chains in discarded biomass materials, the traditional treatment and novel approach for reutilization of discarded biomass were summarized. The discarded biomass mainly come from plant wastes generated in the process of agriculture and forestry production and manufacturing processes, animal wastes generated in the process of animal husbandry and fishery production as well as the residual wastes produced in the process of food processing and rural living garbage. Compared with the traditional treatment including burning, landfill, feeding and fertilizer, the novel approach for reutilization of discarded biomass principally allotted to energy, ecology and polymer materials. The prepared functional materials covered in composite materials, biopolymer based adsorbent and flocculant, carrier materials, energy materials, smart polymer materials for medical and other intelligent polymer materials, which can effectively serve the environmental management and human life, such as wastewater treatment, catalyst, new energy, tissue engineering, drug controlled release, and coating. To sum up, the renewable and biodegradable discarded biomass resources play a vital role in the sustainable development of human society, as well as will be put more emphases in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

Supramolecular materials based on hydrogen-bonded polymers

NARCIS (Netherlands)

ten Brinke, Gerrit; Ruokolainen, Janne; Ikkala, Olli; Binder, W

2007-01-01

Combining supramolecular principles with block copolymer self-assembly offers unique possibilities to create materials with responsive and/or tunable properties. The present chapter focuses on supramolecular materials based on hydrogen bonding and (block co-) polymers. Several cases will be

MLKL forms disulfide bond-dependent amyloid-like polymers to induce necroptosis.

Science.gov (United States)

Liu, Shuzhen; Liu, Hua; Johnston, Andrea; Hanna-Addams, Sarah; Reynoso, Eduardo; Xiang, Yougui; Wang, Zhigao

2017-09-05

Mixed-lineage kinase domain-like protein (MLKL) is essential for TNF-α-induced necroptosis. How MLKL promotes cell death is still under debate. Here we report that MLKL forms SDS-resistant, disulfide bond-dependent polymers during necroptosis in both human and mouse cells. MLKL polymers are independent of receptor-interacting protein kinase 1 and 3 (RIPK1/RIPK3) fibers. Large MLKL polymers are more than 2 million Da and are resistant to proteinase K digestion. MLKL polymers are fibers 5 nm in diameter under electron microscopy. Furthermore, the recombinant N-terminal domain of MLKL forms amyloid-like fibers and binds Congo red dye. MLKL mutants that cannot form polymers also fail to induce necroptosis efficiently. Finally, the compound necrosulfonamide conjugates cysteine 86 of human MLKL and blocks MLKL polymer formation and subsequent cell death. These results demonstrate that disulfide bond-dependent, amyloid-like MLKL polymers are necessary and sufficient to induce necroptosis.

Ceramic/polymer functionally graded material (FGM) lightweight armor system

Energy Technology Data Exchange (ETDEWEB)

Petrovic, J.J.; McClellan, K.J.

1998-12-31

This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Functionally graded material is an enabling technology for lightweight body armor improvements. The objective was to demonstrate the ability to produce functionally graded ceramic-polymer and ceramic-metal lightweight armor materials. This objective involved two aspects. The first and key aspect was the development of graded-porosity boron-carbide ceramic microstructures. The second aspect was the development of techniques for liquid infiltration of lightweight metals and polymers into the graded-porosity ceramic. The authors were successful in synthesizing boron-carbide ceramic microstructures with graded porosity. These graded-porosity boron-carbide hot-pressed pieces were then successfully liquid-infiltrated in vacuum with molten aluminum at 1,300 C, and with liquid polymers at room temperature. Thus, they were able to demonstrate the feasibility of producing boron carbide-aluminum and boron carbide-polymer functionally graded materials.

Polymer materials basic research needs for energy applications

Energy Technology Data Exchange (ETDEWEB)

Macknight, W.J.; Baer, E.; Nelson, R.D. (eds.)

1978-08-01

The larger field covered in the workshop consists of (1) synthesis and characterization, (2) physical chemistry, (3) physics, and (4) engineering. Polymeric materials are properly regarded as new materials in their own right, not as replacements for existing materials. As such they need to be studied to understand the properties which are unique to them by virtue of their particular molecular structures. Technological applications will rationally follow from such studies. It is the objective of this report to point out basic research needs in polymer materials related to energy. The development of sophisticated instrumentation makes the task of molecular characterization possible on a level hitherto unattainable. Many of these instruments because of their size and complexity must of necessity be located at the DOE National Laboratories. The importance of personnel trained in the polymer field located at these facilities is emphasized. In the past there has been relatively little concerted polymer research within the energy community. This report attempts to describe the present situation and point out some needs and future research directions. (GHT)

EFRC: Polymer-Based Materials for Harvesting Solar Energy (stimulus)"

Energy Technology Data Exchange (ETDEWEB)

Russell, Thomas P. [Univ. of Massachusetts, Amherst, MA (United States)

2016-12-08

The University of Massachusetts Amherst is proposing an Energy Frontier Research Center (EFRC) on Polymer-Based Materials for Harvesting Solar Energy that will integrate the widely complementary experimental and theoretical expertise of 23 faculty at UMass-Amherst Departments with researchers from the University of Massachusetts Lowell, University of Pittsburgh, the Pennsylvania State University and Konarka Technologies, Inc. Collaborative efforts with researchers at the Oak Ridge National Laboratory, the University of Bayreuth, Seoul National University and Tohoku University will complement and expand the experimental efforts in the EFRC. Our primary research aim of this EFRC is the development of hybrid polymer-based devices with efficiencies more than twice the current organic-based devices, by combining expertise in the design and synthesis of photoactive polymers, the control and guidance of polymer-based assemblies, leadership in nanostructured polymeric materials, and the theory and modeling of non-equilibrium structures. A primary goal of this EFRC is to improve the collection and conversion efficiency of a broader spectral range of solar energy using the directed self-assembly of polymer-based materials so as to optimize the design and fabrication of inexpensive devices.

Analysis of Void Growth and Coalescence in Porous Polymer Materials. Coalescence in Polymer Materials

Directory of Open Access Journals (Sweden)

S. A. Reffas

2013-06-01

Full Text Available The use of polymeric materials in engineering applications is growing more and more all over the world. This issue requests new methodologies of analysis in order to assess the material’s capability to withstand complex loads. The use of polyacetal in engineering applications has increased rapidly in the last decade. In order to evaluate the behavior, the damage and coalescence of this type of polymer, a numerical method based on damage which occurs following several stages (nucleation of cavities, their growth and coalescence in more advanced stages of deformation is proposed in this work. A particular attention is given on the stress-strain and the volumetric strain evolution under different triaxiality and for three initial void shapes. Its application to polyacetal allows approving this approach for technical polymers. Finally, this method allow us to compare the obtained results of basic calculations at different triaxiality and to discuss their possible influence on the initial size and the geometrical shape of the porosity on the material failure.

Blended polymer materials extractable with supercritical carbon dioxide

Science.gov (United States)

Cai, Mei

Supercritical carbon dioxide is drawing more and more attention because of its unique solvent properties along with being environmentally friendly. Historically most of the commercial interests of supercritical carbon dioxide extraction are in the food industry, pharmaceutical industry, environmental preservation and polymer processing. Recently attention has shifted from the extraction of relatively simple molecules to more complex systems with a much broader range of physical and chemical transformations. However the available data show that a lot of commercially valuable substances are not soluble in supercritical carbon dioxide due to their polar structures. This fact really limits the application of SCF extraction technology to much broader industrial applications. Therefore, the study of a polymer's solubility in a given supercritical fluid and its thermodynamic behavior becomes one of the most important research topics. The major objective of this dissertation is to develop a convenient and economic way to enhance the polymer's solubility in supercritical carbon dioxide. Further objective is to innovate a new process of making metal casting parts with blended polymer materials developed in this study. The key technique developed in this study to change a polymer's solubility in SCF CO2 is to thermally blend a commercially available and CO2 non-soluble polymer material with a low molecular weight CO2 soluble organic chemical that acts as a co-solute. The mixture yields a plastic material that can be completely solubilized in SCF CO2 over a range of temperatures and pressures. It also exhibits a variety of physical properties (strength, hardness, viscosity, etc.) depending on variations in the mixture ratio. The three organic chemicals investigated as CO2 soluble materials are diphenyl carbonate, naphthalene, and benzophenone. Two commercial polymers, polyethylene glycol and polystyrene, have been investigated as CO2 non-soluble materials. The chemical

Integrated Photonic Devices Incorporating Low-Loss Fluorinated Polymer Materials

Directory of Open Access Journals (Sweden)

Hyung-Jong Lee

2011-06-01

Full Text Available Low-loss polymer materials incorporating fluorinated compounds have been utilized for the investigation of various functional optical devices useful for optical communication and optical sensor systems. Since reliability issues concerning the polymer device have been resolved, polymeric waveguide devices have been gradually adopted for commercial application systems. The two most successfully commercialized polymeric integrated optic devices, variable optical attenuators and digital optical switches, are reviewed in this paper. Utilizing unique properties of optical polymers which are not available in other optical materials, novel polymeric optical devices are proposed including widely tunable external cavity lasers and integrated optical current sensors.

An affine microsphere approach to modeling strain-induced crystallization in rubbery polymers

Science.gov (United States)

Nateghi, A.; Dal, H.; Keip, M.-A.; Miehe, C.

2018-01-01

Upon stretching a natural rubber sample, polymer chains orient themselves in the direction of the applied load and form crystalline regions. When the sample is retracted, the original amorphous state of the network is restored. Due to crystallization, properties of rubber change considerably. The reinforcing effect of the crystallites stiffens the rubber and increases the crack growth resistance. It is of great importance to understand the mechanism leading to strain-induced crystallization. However, limited theoretical work has been done on the investigation of the associated kinetics. A key characteristic observed in the stress-strain diagram of crystallizing rubber is the hysteresis, which is entirely attributed to strain-induced crystallization. In this work, we propose a micromechanically motivated material model for strain-induced crystallization in rubbers. Our point of departure is constructing a micromechanical model for a single crystallizing polymer chain. Subsequently, a thermodynamically consistent evolution law describing the kinetics of crystallization on the chain level is proposed. This chain model is then incorporated into the affine microsphere model. Finally, the model is numerically implemented and its performance is compared to experimental data.

Helical Polyacetylenes Induced via Noncovalent Chiral Interactions and Their Applications as Chiral Materials.

Science.gov (United States)

Maeda, Katsuhiro; Yashima, Eiji

2017-08-01

Construction of predominantly one-handed helical polyacetylenes with a desired helix sense utilizing noncovalent chiral interactions with nonracemic chiral guest compounds based on a supramolecular approach is described. As with the conventional dynamic helical polymers possessing optically active pendant groups covalently bonded to the polymer chains, this noncovalent helicity induction system can show significant chiral amplification phenomena, in which the chiral information of the nonracemic guests can transfer with high cooperativity through noncovalent bonding interactions to induce an almost single-handed helical conformation in the polymer backbone. An intriguing "memory effect" of the induced macromolecular helicity is observed for some polyacetylenes, which means that the helical conformations induced in dynamic helical polyacetylene can be transformed into metastable static ones by tuning their helix-inversion barriers. Potential applications of helical polyacetylenes with controlled helix sense constructed by the "noncovalent helicity induction and/or memory effect" as chiral materials are also described.

Polymer-Block-Polypeptides and Polymer-Conjugated Hybrid Materials as Stimuli-Responsive Nanocarriers for Biomedical Applications.

Science.gov (United States)

John, Johnson V; Johnson, Renjith P; Heo, Min Seon; Moon, Byeong Kyu; Byeon, Seong Jin; Kim, Il

2015-01-01

Stimuli-responsive nanocarriers are a class of soft materials that includes natural polymers, synthetic polymers, and polypeptides. Recently, modern synthesis tools such as atom transfer radical polymerization, reversible addition-fragmentation chain transfer polymerization, nitroxide-mediated radical polymerization, ring-opening polymerization of α-amino acid N-carboxyanhydrides, and various "click" chemistry strategies were simultaneously employed for the design and synthesis of nanosized drug delivery vehicles. Importantly, the research focused on the improvement of the nanocarrier targetability and the site-specific, triggered release of therapeutics with high drug loading efficiency and minimal drug leakage during the delivery to specific targets. In this context, nanocarriers responsive to common stimuli such as pH, temperature, redox potential, light, etc. have been widely used for the controlled delivery of therapeutics to pathological sites. Currently, different synthesis and self-assembly strategies improved the drug loading efficacy and targeted delivery of therapeutic agents to the desired site. In particular, polypeptide-containing hybrid materials have been developed for the controlled delivery of therapeutic agents. Therefore, stimuli-sensitive synthetic polypeptide-based materials have been extensively investigated in recent years. This review focuses on recent advances in the development of polymer-block-polypeptides and polymer-conjugated hybrid materials that have been designed and evaluated for various stimuli-responsive drug and gene delivery applications.

Photodeformable polymer materials: towards light-driven spoke-type micromotor application

Science.gov (United States)

Zhu, Yutian; Zheng, Lihui; Liu, Zhao; Liu, Heng; Yu, Yanlei

2014-06-01

Using a photodeformable polymer material, liquid-crystalline polymer incorporated with azobenzene moieties, a spoke-type micromotor is designed, which could convert light energy directly into mechanical work. It consists of four driving belts, whose mechanical model is established and the driving moment of the micromotor upon irradiation with UV light and without photoirradiation is calculated, respectively. According to the calculated driving moment, the UV light and the visible light are arranged to irradiate from parallel and opposite direction of the micromotor simultaneously, which convert the bending deflection of the photodeformable polymer material belts to continuous rotation of the micromotor. As light is a green energy source that can be controlled remotely, instantly and without the aid of electric wires, the photodeformable polymer material has great potential to be utilized in micro-actuator and other relative applications.

Method of processing radiation-contaminated organic polymer materials

International Nuclear Information System (INIS)

Kobayashi, Yoshii.

1980-01-01

Purpose: To process radiation contaminated organic high polymer materials with no evolution of toxic gases, at low temperature and with safety by hot-acid immersion process using sulfuric acid-hydrogen peroxide. Method: Less flammable or easily flammable organic polymers contaminated with radioactive substances, particularly with long life actinoid are heated and carbonized in concentrated sulfuric acid. Then, aqueous 30% H 2 O 2 solution is continuously added dropwise as an oxidizing agent till the solution turns colourless. If the carbonization was insufficient, addition of H 2 O 2 solution is stopped temporarily and the carbonization is conducted again. Thus, the organic polymers are completely decomposed by the wet oxidization. Then, the volume of the organic materials to be discharged is decreased and the radioactive substances contained are simultaneously concentrated and collected. (Seki, T.)

Study of multilayer polymer materials after ionization treatment

Science.gov (United States)

Tarasyuk, V. T.; Semkina, A. A.; Solovyeva, V. I.; Fedotova, D. D.; Strokova, N. E.; Malenko, D. M.; Baranov, O. V.; Bakumenko, A. V.; Puchkov, S. N.; Prokopenko, A. V.

2017-12-01

Electron-beam technologies of food products processing involves the use of modern packaging materials in form of polymer films of different composition. The objective of the research is to study the impact of accelerated electrons on the structure of the polymeric packaging materials used for storage of agricultural products. It was investigated radiation exposure on film material PE/PA (80/20) with a thickness of 80 mkm. This film used for storage of vegetables and fruits and has the necessary indicators for gas and vapor permeability. Electron beam treatment of the films was performed on a compact radiation sterilization installation with local bio-protection with electron energy of 5 MeV. A polymer films were irradiated with doses from 1 to 10 kGy. Changing the structure of the film composition was monitored by IR spectrometry. As a result of irradiation by accelerated electrons with doses up to 18 kGy is established that the polymer film is modification of the polymeric material in the form of a partial degradation with subsequent intra-molecular crosslinking. This improves the physico-mechanical properties in the transverse direction, and such film can be used for food packaging before electron-beam treatment.

Distribution of products in polymer materials induced by ion-beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Sugimoto, Masaki; Kudoh, Hisaaki; Sasuga, Tsuneo; Seguchi, Tadao [Japan Atomic Energy Research Inst., Tokyo (Japan); Hama, Yoshimasa; Hamanaka, Ken-ichi; Matsumoto, Hideya

1997-03-01

The depth profile of double bond formed in low density polyethylene (LDPE) sheet by ion beams irradiation was observed by a micro FT-IR spectrometer in order to investigate the linear energy transfer (LET) dependency on radiation effects to polymer materials. The distribution of double bond formation in LDPE by irradiation of light ions as H+ was found to be same with the dose distribution calculated from TRIM code, and the yield was also same with that by gamma-rays irradiation, which means that the LET dependency is very small. However, the distribution of double bond to depth was much different from the calculated depth-dose in heavy ions irradiation as Ar and Kr. Then, the dose evaluation was difficult from the TRIM code calculation for heavy ions. (author)

Radiation-induced polymerization and radiation effect on polymers

International Nuclear Information System (INIS)

Seguchi, Tadao

1977-12-01

The processes of radiation-induced polymerization of monomers and also radiation effects on polymers have been studied by instrumental analyses of electron spin resonance (ESR), nuclear magnetic resonance (NMR) and electron microscopy. In radiation-induced polymerization, graft-copolymerization and absorbed state polymerization were taken up. For graft-copolymerization, monomers such as methylmethacrylate and butadiene were made to react with irradiated polyethylene, and behaviors of the initiating radicals and propagating radicals were followed under the reaction by ESR. For absorbed state polymerization, acrylonitrile/zeolite and methylmethacrylate/zeolite were chosen. Absorbed monomers were irradiated at 77 0 K and polymerized at room temperature. Active species and the concentrations were measured by ESR and the yields of polymer were observed by NMR. In radiation effect on polymers, polyvinylfluoride, polyvinylidenfluoride and polytetrafluoroethylene were taken up. Active species trapped in the polymer matrixes were identified and decay and reactivity of the species were also studied. On the basis of information from the electron microscopy and x-ray analysis, radiation effects on these polymers are described. In polytetrafluoroethylene produced by radiation polymerization, the relation between morphology and polymerization conditions and also the process of crystallization during polymerization were studied. (auth.)

Studies of positron induced luminescence from polymers

International Nuclear Information System (INIS)

Xu, J.; Hulett, L.D. Jr.; Lewis, T.A.; Tolk, N.H.

1994-01-01

Light emission from polymers (anthracene dissolved in polystryrene) induced by low-energy positrons and electrons has been studied. Results indicate a clear difference between optical emissions under positron and electron bombardment. The positron-induced luminescence spectrum is believed to be generated by both collisional and annihilation processes

Radiation synthesis of functionalising polymer and creation of composition materials on their basis

International Nuclear Information System (INIS)

Mun, G.A.; Nurkeeva, Z.S.; Akhmetkalieva, G.T.; Urkimbaeva, P.I.; Park, L.K.; Lyssukhin, S.N.; Chakrov, P.V.

2005-01-01

Full text: Hydrogels are three-dimensional crosslinked hydrophilic polymers capable of swelling in water and retaining possibly huge volumes of water in the swollen state. The ability of polymer gels to undergo substantial swelling and collapse, as a function of their environment is one of the most remarkable properties of these materials. By this reason such polymer hydrogels belong to so-called 'intelligent', 'smart' or stimuli-responsive materials. The phenomenon of gel volume transitions, which can be induced by temperature, pH, ionic environment and electric fields, has prompted researchers to investigate gels as potential sensors, force actuators, controllable membranes for separations, and modulators for delivery of drugs and other molecules. One of the most perspective applications of stimuli-responsive hydrogels is the designing of controlled drug delivery devices for medicine. In particular, so-called thermo-responsible hydrogels, which undergo a volume phase transition in an aqueous environment induced by a change in temperature, are the most interesting class of stimuli-responsive polymers. It should be noted that all such polymers were obtained usually by homo polymerization of amphiphilic monomers which have hydrophilic and hydrophobic fragments in their structure simultaneously. We used another approach for synthesis of thermo sensitive polymers of linear and cross-linked structure. This approach includes radiation copolymerization of monomers having significant difference in hydrophobic/hydrophilic balance. Some of thermo-sensitive hydrogels and water-soluble polymers were obtained by copolymerization of the following monomeric pairs: vinyl ether of ethyleneglycol (VEEG)-vinyl butyl ether (VBE), VEEG-vinyl isobutyl ether, vinyl ether of diethyleneglycol-VBE, VEEG-hydroxyethylmethacrylate (HEMA), hydroxyethylacrylate (HEA)-HEMA, HEA- butylacrylate, HEA-methylacrylate. The synthesis regularities have been studied. The linear copolymers show lower

Fundamental radiation effect on polymers energy transfer from radiation to polymer

International Nuclear Information System (INIS)

Seguchi, T.

2007-01-01

Polymer modification as cross-link, chain scission, and graft-polymerization by radiation is initiated by the quantum energy transferred from radiation to polymers. The active species for chemical reactions are produced through ionization or activation of polymer molecules for any radiation source. The energy transfer occurs mainly by ionic interaction between radiation and polymer molecule, and the contribution from the collision interaction is miner. The radiation of electromagnetic wave as X-ray or γ-ray generates the energetic electron which induces ionic interaction with polymer molecule. The energy loss profile along the penetration to polymer material is much different among the radiation sources of EB, γ-ray, and ion beams in the macroscopic mechanism. In this article, the behavior of single event, that is, the event induced by one electron, γ-ray, ion, and neutron is described by the macroscopic mechanism and by the microscopic mechanism. (authors)

Coupled effects of director orientations and boundary conditions on light induced bending of monodomain nematic liquid crystalline polymer plates

International Nuclear Information System (INIS)

You, Yue; Ding, Shurong; Huo, Yongzhong; Xu, Changwei

2012-01-01

A photo-chromic liquid crystal polymers (LCPs) is a smart material for large light-activated variation or bending to transfer luminous energy into mechanical energy. We study the light induced behavior by modeling planar and homeotropic nematic network polymer plates. We effectively illustrate some reported experimental outcomes and theoretically predict some possible bending patterns. This paper constructs an understanding between the bending behaviors and interactions among the alignments, aspect ratios and boundary conditions, etc. Our work provides information on optimizing light induced bending in the process of micro-opto-mechanical system (MOMS) design. (paper)

Polymer-coated compliant receivers for intact laser-induced forward transfer of thin films: experimental results and modelling

Science.gov (United States)

Feinaeugle, Matthias; Horak, Peter; Sones, Collin L.; Lippert, Thomas; Eason, Rob W.

2014-09-01

In this study, we investigate both experimentally and numerically laser-induced forward transfer (LIFT) of thin films to determine the role of a thin polymer layer coating the receiver with the aim of modifying the rate of deceleration and reduction of material stress preventing intact material transfer. A numerical model of the impact phase during LIFT shows that such a layer reduces the modelled stress. The evolution of stress within the transferred deposit and the substrate as a function of the thickness of the polymer layer, the transfer velocity and the elastic properties of the polymer are evaluated. The functionality of the polymer layer is verified experimentally by LIFT printing intact 1- m-thick bismuth telluride films and polymeric light-emitting diode pads onto a layer of 12-m-thick polydimethylsiloxane and 50-nm-thick poly(3,4-ethylenedioxythiophene) blended with poly(styrenesulfonate) (PEDOT:PSS), respectively. Furthermore, it is demonstrated experimentally that the introduction of such a compliant layer improves adhesion between the deposit and its substrate.

Investigation of the possibilities for application of NORM into polymer materials

OpenAIRE

Srebrenkoska, Vineta

2016-01-01

The main aim of the proposed STSM project is to perform: • Comparison of fly ash characteristics (chemical composition, granulometry and density) from different origins: Slovenia and Macedonia. • Characterization of the polymer materials: thermoset and thermoplastic. • Estimate the possibilities for preparing of the composites based on fly ash as NORM material from different origins and polymers. The analyses of the inorganic fillers and organic polymer matrices will be made in or...

Characterization of temperature-dependent optical material properties of polymer powders

Energy Technology Data Exchange (ETDEWEB)

Laumer, Tobias [Bayerisches Laserzentrum GmbH, 91052 Erlangen (Germany); SAOT Erlangen Graduate School in Advanced Optical Technologies, 91052 Erlangen (Germany); CRC Collaborative Research Center 814 - Additive Manufacturing, 91052 Erlangen (Germany); Stichel, Thomas; Bock, Thomas; Amend, Philipp [Bayerisches Laserzentrum GmbH, 91052 Erlangen (Germany); CRC Collaborative Research Center 814 - Additive Manufacturing, 91052 Erlangen (Germany); Schmidt, Michael [Bayerisches Laserzentrum GmbH, 91052 Erlangen (Germany); University of Erlangen-Nürnberg, Institute of Photonic Technologies, 91052 Erlangen (Germany); SAOT Erlangen Graduate School in Advanced Optical Technologies, 91052 Erlangen (Germany); CRC Collaborative Research Center 814 - Additive Manufacturing, 91052 Erlangen (Germany)

2015-05-22

In former works, the optical material properties of different polymer powders used for Laser Beam Melting (LBM) at room temperature have been analyzed. With a measurement setup using two integration spheres, it was shown that the optical material properties of polymer powders differ significantly due to multiple reflections within the powder compared to solid bodies of the same material. Additionally, the absorption behavior of the single particles shows an important influence on the overall optical material properties, especially the reflectance of the powder bed. Now the setup is modified to allow measurements at higher temperatures. Because crystalline areas of semi-crystalline thermoplastics are mainly responsible for the absorption of the laser radiation, the influence of the temperature increase on the overall optical material properties is analyzed. As material, conventional polyamide 12 and polypropylene as new polymer powder material, is used. By comparing results at room temperature and at higher temperatures towards the melting point, the temperature-dependent optical material properties and their influence on the beam-matter interaction during the process are discussed. It is shown that the phase transition during melting leads to significant changes of the optical material properties of the analyzed powders.

From precision polymers to complex materials and systems

Science.gov (United States)

Lutz, Jean-François; Lehn, Jean-Marie; Meijer, E. W.; Matyjaszewski, Krzysztof

2016-05-01

Complex chemical systems, such as living biological matter, are highly organized structures based on discrete molecules in constant dynamic interactions. These natural materials can evolve and adapt to their environment. By contrast, man-made materials exhibit simpler properties. In this Review, we highlight that most of the necessary elements for the development of more complex synthetic matter are available today. Using modern strategies, such as controlled radical polymerizations, supramolecular polymerizations or stepwise synthesis, polymers with precisely controlled molecular structures can be synthesized. Moreover, such tailored polymers can be folded or self-assembled into defined nanoscale morphologies. These self-organized macromolecular objects can be at thermal equilibrium or can be driven out of equilibrium. Recently, in the latter case, interesting dynamic materials have been developed. However, this is just a start, and more complex adaptive materials are anticipated.

Functionalised hybrid materials of conducting polymers with individual wool fibers.

Science.gov (United States)

Kelly, Fern M; Johnston, James H; Borrmann, Thomas; Richardson, Michael J

2008-04-01

Composites of natural protein materials, such as merino wool, with the conducting polymers polypyrrole (PPy) and polyaniline (PAn) have been successfully synthesised. In doing so, hybrid materials have been produced in which the mechanical strength and flexibility of the fibers is retained whilst also incorporating the desired chemical and electrical properties of the polymer. Scanning electron microscopy shows PPy coatings to comprise individual polymer spheres, approximately 100 to 150 nm in diameter. The average size of the polymer spheres of PAn was observed to be approximately 50 to 100 nm in diameter. These spheres fuse together in a continuous sheet to coat the fibers in their entirety. The reduction of silver ions to silver metal nanoparticles onto the redox active polymer surface has also been successful and thus imparts anti-microbial properties to the hybrid materials. This gives rise to further applications requiring the inhibition of microbial growth. The chemical and physical characterisation of such products has been undertaken through scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electrical conductivity, cyclic voltammetry, X-ray photoelectron spectroscopy (XPS) and the testing of their anti-microbial activity.

Design, preparation, and application of ordered porous polymer materials

International Nuclear Information System (INIS)

Liu, Qingquan; Tang, Zhe; Ou, Baoli; Liu, Lihua; Zhou, Zhihua; Shen, Shaohua; Duan, Yinxiang

2014-01-01

Ordered porous polymer (OPP) materials have extensively application prospects in the field of separation and purification, biomembrane, solid supports for sensors catalysts, scaffolds for tissue engineering, photonic band gap materials owing to ordered pore arrays, uniform and tunable pore size, high specific surface area, great adsorption capacity, and light weight. The present paper reviewed the preparation techniques of OPP materials like breath figures, hard template, and soft template. Finally, the applications of OPP materials in the field of separation, sensors, and biomedicine are introduced, respectively. - Highlights: • Breath figures involve polymer casting under moist ambience. • Hard template employs monodisperse colloidal spheres as a template. • Soft template utilizes the etched block in copolymers as template

3D optical printing of piezoelectric nanoparticle-polymer composite materials.

Science.gov (United States)

Kim, Kanguk; Zhu, Wei; Qu, Xin; Aaronson, Chase; McCall, William R; Chen, Shaochen; Sirbuly, Donald J

2014-10-28

Here we demonstrate that efficient piezoelectric nanoparticle-polymer composite materials can be optically printed into three-dimensional (3D) microstructures using digital projection printing. Piezoelectric polymers were fabricated by incorporating barium titanate (BaTiO3, BTO) nanoparticles into photoliable polymer solutions such as polyethylene glycol diacrylate and exposing to digital optical masks that could be dynamically altered to generate user-defined 3D microstructures. To enhance the mechanical-to-electrical conversion efficiency of the composites, the BTO nanoparticles were chemically modified with acrylate surface groups, which formed direct covalent linkages with the polymer matrix under light exposure. The composites with a 10% mass loading of the chemically modified BTO nanoparticles showed piezoelectric coefficients (d(33)) of ∼ 40 pC/N, which were over 10 times larger than composites synthesized with unmodified BTO nanoparticles and over 2 times larger than composites containing unmodified BTO nanoparticles and carbon nanotubes to boost mechanical stress transfer efficiencies. These results not only provide a tool for fabricating 3D piezoelectric polymers but lay the groundwork for creating highly efficient piezoelectric polymer materials via nanointerfacial tuning.

Radiation detectors based by polymer materials

International Nuclear Information System (INIS)

Cherestes, Margareta; Cherestes, Codrut; Constantinescu, Livia

2004-01-01

Scintillation counters make use of the property of certain chemical compounds to emit short light pulses after excitation produced by the passage of charged particles or photons of high energy. These flashes of light are detected by a photomultiplier tube that converts the photons into a voltage pulse. The light emitted from the detector also can be collected, focussed and dispersed by a CCD detector. The study of the evolution of the light emission and of the radiation damage under irradiation is a primary topic in the development of radiation hard polymer based scintillator. Polymer scintillator thin films are used in monitoring radiation beam intensities and simultaneous counting of different radiations. Radiation detectors have characteristics which depend on: the type of radiation, the energy of radiation, and the material of the detector. Three types of polymer thin films were studied: a polyvinyltoluene based scintillator, fluorinated polyimide and PMMA. (authors)

Metal{Polymer Hybrid Materials For Flexible Transparent Conductors

Science.gov (United States)

Narayanan, Sudarshan

The field of organic electronics, till recently a mere research topic, is currently making rapid strides and tremendous progress into entering the mainstream electronics industry with several applications and products such as OLED televisions, curved displays, wearable devices, flexible solar cells, etc. already having been commercialized. A major component in these devices, especially for photovoltaic applications, is a transparent conductor used as one of the electrodes, which in most commercial applications are highly doped wide bandgap semiconducting oxides also called Transparent Conducting Oxides (TCOs). However, TCOs exhibit inherent disadvantages such as limited supply, brittle mechanical properties, expensive processing that present major barriers for the more widespread economic use in applications such as exible transparent conductors, owing to which suitable alternative materials are being sought. In this context we present two approaches in realizing alternative TCs using metal-polymer hybrid materials, with high figures of merit that are easily processable, reasonably inexpensive and mechanically robust as well. In this context, our first approach employs laminated metal-polymer photonic bandgap structures to effectively tune optical and electrical properties by an appropriate design of the material stack, factoring in the effect of the materials involved, the number of layers and layer properties. We have found that in the case of a four-bilayer Au/polystyrene (AujPS) laminate structure, an enhancement in optical transmittance of ˜ 500% in comparison to a monolithic A film of equivalent thickness, can be achieved. The high conductivity (˜ 106 O--1cm--1) of the metallic component, Au in this case, also ensures planar conductivity; metallic inclusions in the dielectric polymer layer can in principle give rise to out-of-plane conductivity as well enabling a fully functional TC. Such materials also have immense potential for several other applications

Control of Porosity in Ladder Polymers by Solvent-induced Aggregation

Science.gov (United States)

Brady, Michael; Gamo, Eri; Wang, Cheng; Xia, Yan

Porous polymers hold promise as materials for gas absorption, membranes, and organic electronics. In all of these applications, attaining in-plane ordering of backbones and thus porous free volume impacts the ability to adsorb gas, selectively filter molecules, and conduct charges. In this work, hard and soft x-ray scattering and soft x-ray spectroscopy are of focus to study the pore structure, induced by the solution-driven aggregation of ladder polymer thin films made of LP-1 and LP-2. Using GISAXS and AFM it is shown that thermal annealing drives the growth of crystallites in thin films. Due to the completely sp2nature of the ladder polymer backbones, it is expected that backbones are extremely stiff and thus preventing them from packing once left in a metastable state following casting. Therefore, the combination of GIWAXS and GISAXS will be shown to be critical in correctly understanding how pores develop in this 700 m2/g sorbent (N2). Finally, application in CO2/N2 separation membranes towards carbon sequestration will be presented that show gas selectivity is achieved through heteroatom incorporation and polymer blending. In this talk, focus will be placed on state-of-the-art x-ray scattering and spectroscopy, highlighting the importance of chemically sensitive structural information enabled by the combination of spectroscopy and scattering at play with the use of resonant soft x-rays.

Multilayer Electroactive Polymer Composite Material Comprising Carbon Nanotubes

Science.gov (United States)

Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Draughon, Gregory K. (Inventor)

2009-01-01

An electroactive material comprises multiple layers of electroactive composite with each layer having unique dielectric, electrical and mechanical properties that define an electromechanical operation thereof when affected by an external stimulus. For example, each layer can be (i) a 2-phase composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation, or (ii) a 3-phase composite having the elements of the 2-phase composite and further including a third component of micro-sized to nano-sized particles of an electroactive ceramic incorporated in the polymer matrix.

Porous Polymer Drug-Eluting Coating Prepared by Radiation Induced Polymerization

International Nuclear Information System (INIS)

Veres, M.; Beiler, B.; Himics, L.; Tóth, S.; Koós, M.

2010-01-01

Many areas of modern medicine are almost unimaginable without the use of different kinds of implants. They used as replacements, supports, auxiliary devices etc. for various parts or functions of the body. Their use has many advantages, however there could be some drawbacks too, like the possibility of rejection, inflammation and other side-effects. Many of these drawbacks are directly related to the materials used for the implant fabrication. Coatings are widely used to eliminate the unwanted effects appearing after the implantation. In addition to the protection and separation of tissues from the implant material they could also enhance the functionality and the acceptance of the artificial device and also promote the regeneration of the tissues after the intervention. Drug-eluting coatings are a good example for the latter. By delivery and controlled elution of drugs they could actively suppress inflammatory reactions, allergy and rejection of the implant, and their activity is localized to the place where these effects could mainly occur – to the region of the implant. This project is aimed to develop a drug-eluting porous polymer coating by radiation induced polymerization that can be used in different medical implants. The primary objects for this research are coronary stents however these porous layers could have perspective in other types of medical devices too. The main objectives are to develop a method for coating the surface of medical grade metallic alloy wires, plates and tubes with a porous polymer nanocomposite layer prepared by radiation induced polymerization and to characterize the obtained coatings

Porous Polymer Drug-Eluting Coating Prepared by Radiation Induced Polymerization

Energy Technology Data Exchange (ETDEWEB)

Veres, M.; Beiler, B.; Himics, L.; Tóth, S.; Koós, M., E-mail: vm@szfki.hu [Hungarian Academy of Sciences, Research Institute for Solid State Physics and Optics, Department of Laser Applications, Konkoly Thege Miklós ut 29-33, 1121 Budapest, P.O. Box 49, 1525 Budapest (Hungary)

2010-07-01

Many areas of modern medicine are almost unimaginable without the use of different kinds of implants. They used as replacements, supports, auxiliary devices etc. for various parts or functions of the body. Their use has many advantages, however there could be some drawbacks too, like the possibility of rejection, inflammation and other side-effects. Many of these drawbacks are directly related to the materials used for the implant fabrication. Coatings are widely used to eliminate the unwanted effects appearing after the implantation. In addition to the protection and separation of tissues from the implant material they could also enhance the functionality and the acceptance of the artificial device and also promote the regeneration of the tissues after the intervention. Drug-eluting coatings are a good example for the latter. By delivery and controlled elution of drugs they could actively suppress inflammatory reactions, allergy and rejection of the implant, and their activity is localized to the place where these effects could mainly occur – to the region of the implant. This project is aimed to develop a drug-eluting porous polymer coating by radiation induced polymerization that can be used in different medical implants. The primary objects for this research are coronary stents however these porous layers could have perspective in other types of medical devices too. The main objectives are to develop a method for coating the surface of medical grade metallic alloy wires, plates and tubes with a porous polymer nanocomposite layer prepared by radiation induced polymerization and to characterize the obtained coatings.

Graphene-epoxy flexible transparent capacitor obtained by graphene-polymer transfer and UV-induced bonding.

Science.gov (United States)

Sangermano, Marco; Chiolerio, Alessandro; Veronese, Giulio Paolo; Ortolani, Luca; Rizzoli, Rita; Mancarella, Fulvio; Morandi, Vittorio

2014-02-01

A new approach is reported for the preparation of a graphene-epoxy flexible transparent capacitor obtained by graphene-polymer transfer and UV-induced bonding. SU8 resin is employed for realizing a well-adherent, transparent, and flexible supporting layer. The achieved transparent graphene/SU8 membrane presents two distinct surfaces: one homogeneous conductive surface containing a graphene layer and one dielectric surface typical of the epoxy polymer. Two graphene/SU8 layers are bonded together by using an epoxy photocurable formulation based on epoxy resin. The obtained material showed a stable and clear capacitive behavior. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radiolytically-induced novel materials and their application to waste processing

International Nuclear Information System (INIS)

Massimo Bertino; Akira Tokuhiro; Tadashi Tokuhiro

2007-01-01

In the present NEER project we investigated two different types of gel materials with respect to potential applications in environmental remediation, including mixed waste generated from the nuclear fuel cycles. The materials under study were: (1) silica-polymer based aerogel composites into which specific metallic cations diffuse into and remain, and (2) polymer gels made of thermo-sensitive polymer networks, whose functional groups can be ''tailored'' to have a preferred affinity for specific cations, again diffusing into and remaining in the network under a volumetrically, contractive phase-transition. The molecular, diffusion of specific cations, including those of concern in low-level waste streams, into the gel materials studied here indicates that a scaled, engineered system can be designed so that it is passive; that is, minimal (human) intervention and risk would be involved in encapsulating LLW species. In addition, the gel materials hold potential significance in environmental remediation of and recovery of metallic cations identified in respective domains and physico-chemical processes. In brief, silica gels start as aqueous/liquid solutions of base catalyzed silica hydrogels and metal ions (targeted species), such as silver. The metal ions are reduced radiolytically and migrate through the solution to form clusters. Upon post-irradiation processing, aerogel monoliths, extremely lightweight but mechanically strong, that encapsulate the metals are produced. Interestingly the radiolytic or photonic source can be gamma-rays and/or other rays from ''artificial sources'', such as reactors, or ''inherent sources'' like those characterizing mixed waste. Polymer gels, in contrast exhibit thermally-induced volumetric contraction at 20-50 C by expelling water from the gels physical state. Further, some functional groups that capture di- or tri-valent cations from aqueous solutions can be incorporated into the polymer networks on synthesis, including by radiolytic

Radiolytically-induced novel materials and their application to waste processing

Energy Technology Data Exchange (ETDEWEB)

Massimo Bertino, Akira Tokuhiro, Tadashi Tokuhiro

2007-12-05

In the present NEER project we investigated two different types of gel materials with respect to potential applications in environmental remediation, including mixed waste generated from the nuclear fuel cycles. The materials under study were: (1) silica-polymer based aerogel composites into which specific metallic cations diffuse into and remain, and (2) polymer gels made of thermo-sensitive polymer networks, whose functional groups can be ''tailored'' to have a preferred affinity for specific cations, again diffusing into and remaining in the network under a volumetrically, contractive phase-transition. The molecular, diffusion of specific cations, including those of concern in low-level waste streams, into the gel materials studied here indicates that a scaled, engineered system can be designed so that it is passive; that is, minimal (human) intervention and risk would be involved in encapsulating LLW species. In addition, the gel materials hold potential significance in environmental remediation of and recovery of metallic cations identified in respective domains and physico-chemical processes. In brief, silica gels start as aqueous/liquid solutions of base catalyzed silica hydrogels and metal ions (targeted species), such as silver. The metal ions are reduced radiolytically and migrate through the solution to form clusters. Upon post-irradiation processing, aerogel monoliths, extremely lightweight but mechanically strong, that encapsulate the metals are produced. Interestingly the radiolytic or photonic source can be gamma-rays and/or other rays from ''artificial sources'', such as reactors, or ''inherent sources'' like those characterizing mixed waste. Polymer gels, in contrast exhibit thermally-induced volumetric contraction at 20-50 C by expelling water from the gels physical state. Further, some functional groups that capture di- or tri-valent cations from aqueous solutions can be incorporated

Reactive ion etching of polymer materials for an energy harvesting device

DEFF Research Database (Denmark)

Wang, Fei; Bertelsen, Christian Vinther; Skands, Gustav

2012-01-01

In this paper, we have demonstrated deep reactive ion etching (RIE) of two MEMS compatible polymer materials CYTOP and TOPAS, which may be useful for energy harvesting devices. The CYTOP polymer was patterned and used as the electret for the following corona charging while the TOPAS polymer...

Main chain acid-degradable polymers for the delivery of bioactive materials

Science.gov (United States)

Frechet, Jean M. J. [Oakland, CA; Standley, Stephany M [Evanston, IL; Jain, Rachna [Milpitas, CA; Lee, Cameron C [Cambridge, MA

2012-03-20

Novel main chain acid degradable polymer backbones and drug delivery systems comprised of materials capable of delivering bioactive materials to cells for use as vaccines or other therapeutic agents are described. The polymers are synthesized using monomers that contain acid-degradable linkages cleavable under mild acidic conditions. The main chain of the resulting polymers readily degrade into many small molecules at low pH, but remain relatively stable and intact at physiological pH. The new materials have the common characteristic of being able to degrade by acid hydrolysis under conditions commonly found within the endosomal or lysosomal compartments of cells thereby releasing their payload within the cell. The materials can also be used for the delivery of therapeutics to the acidic regions of tumors and other sites of inflammation.

Radiation Synthesis of Superabsorbent Polymers Based on Natural Polymers

International Nuclear Information System (INIS)

Sen, Murat; Hayrabolulu, Hande

2010-01-01

The objectives of proposed research contract were first synthesize superabsorbent polymers based on natural polymers to be used as disposable diapers and soil conditioning materials in agriculture, horticulture and other super adsorbent using industries. We have planned to use the natural polymers; locust beam gum, tara gum, guar gum and sodium alginate on the preparation of natural superabsorbent polymers(SAP). The aqueous solution of natural polymers and their blends with trace amount of monomer and cross-linking agents will be irradiated in paste like conditions by gamma rays for the preparation of cross-linked superabsorbent systems. The water absorption and deswellling capacity of prepared super adsorbents and retention capacity, absorbency under load, suction power, swelling pressure and pet-rewet properties will be determined. Use of these materials instead of synthetic super absorbents will be examined by comparing the performance of finished products. The experimental studies achieved in the second year of project mainly on the effect of radiation on the chemistry of sodium alginate polymers in different irradiation conditions and structure-property relationship particularly with respect to radiation induced changes on the molecular weight of natural polymers and preliminary studies on the synthesis of natural-synthetic hydride super adsorbent polymers were given in details

Comparative study of 150 keV Ar+ and O+ ion implantation induced structural modification on electrical conductivity in Bakelite polymer

Science.gov (United States)

Aneesh Kumar, K. V.; Krishnaveni, S.; Asokan, K.; Ranganathaiah, C.; Ravikumar, H. B.

2018-02-01

A comparative study of 150 keV argon (Ar+) and oxygen (O+) ion implantation induced microstructural modifications in Bakelite Resistive Plate Chamber (RPC) detector material at different implantation fluences have been studied using Positron Annihilation Lifetime Spectroscopy (PALS). Positron lifetime parameters viz., o-Ps lifetime (τ3) and its intensity (I3) upon lower implantation fluences can be interpreted as the cross-linking and the increased local temperature induced diffusion followed by trapping of ions in the interior polymer voids. The increased o-Ps lifetime (τ3) at higher O+ ion implantation fluences indicates chain scission owing to the oxidation and track formation. This is also justified by the X-Ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) results. The modification in the microstructure and electrical conductivity of Bakelite materials are more upon implantation of O+ ions than Ar+ ions of same energy and fluences. The reduced electrical conductivity of Bakelite polymer material upon ion implantation of both the ions is correlated to the conducting pathways and cross-links in the polymer matrix. The appropriate energy and fluence of implanting ions might reduce the leakage current and hence improve the performance of Bakelite RPC detectors.

Solvent-annealing-induced nanowetting in templates: towards tailored polymer nanostructures.

Science.gov (United States)

Chen, Jiun-Tai; Lee, Chih-Wei; Chi, Mu-Huan; Yao, I-Chun

2013-02-25

We study the solvent-annealing-induced nanowetting in templates using porous anodic aluminum oxide membranes. The morphology of polystyrene and poly(methyl methacrylate) nanostructures can be controlled, depending on whether the swollen polymers are in the partial or complete wetting regimes, which are characterized by the spreading coefficient. When the swollen polymers are in the partial wetting regime, polymers wet the nanopores by capillary action, resulting in the formation of polymer nanorods. When the swollen polymers are in the complete wetting regime, polymers form wetting layers in the nanopores, resulting in the formation of polymer nanotubes. The solubility parameters of polymers and solvents are also used to predict the wetting behavior of swollen polymers in cylindrical geometry. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Diffusion and solubility of oxygen in γ-ray irradiated polymer insulation materials

International Nuclear Information System (INIS)

Seguchi, Tadao; Yamamoto, Yasuaki.

1986-03-01

The effects of 60 Co γ-rays irradiation on diffusion and solubility of oxygen in polymer materials for electric cable insulation materials were investigated. The polymers were polyethylene, ethylene-propylene rubber, chlorinated polyethylene, chlorosulphonated polyethylene, and chloroprene rubber. They were pure grade and several types of formulation grade. The sheets of these polymers were irradiated up to 5 - 200 Mrad under vacuum or in oxygen under pressure of 3 - 15 atm at room temperature or at 70 deg C. By a method of gas desorption, the diffusion coefficient (D) and solubility coefficient (S) of oxygen or argon in polymer materials were determined at various temperatures of 10 - 80 deg C. The D and S decreased with increase of dose, and the decrease by irradiation with oxidation was more remarkable than that by irradiation without oxidation. However, the decreases of D and S by irradiation were reduced by the formulation of polymers. The additives in formulated polymers would reduce the reactions of crosslinking or oxidation by γ-ray irradiation. The activation energy of D was scarcely changed by irradiations with and without oxidation. (author)

Investigating accidents involving aircraft manufactured from polymer composite materials

Science.gov (United States)

Dunn, Leigh

This study looks into the examination of polymer composite wreckage from the perspective of the aircraft accident investigator. It develops an understanding of the process of wreckage examination as well as identifying the potential for visual and macroscopic interpretation of polymer composite aircraft wreckage. The in-field examination of aircraft wreckage, and subsequent interpretations of material failures, can be a significant part of an aircraft accident investigation. As the use of composite materials in aircraft construction increases, the understanding of how macroscopic failure characteristics of composite materials may aid the field investigator is becoming of increasing importance.. The first phase of this research project was to explore how investigation practitioners conduct wreckage examinations. Four accident investigation case studies were examined. The analysis of the case studies provided a framework of the wreckage examination process. Subsequently, a literature survey was conducted to establish the current level of knowledge on the visual and macroscopic interpretation of polymer composite failures. Relevant literature was identified and a compendium of visual and macroscopic characteristics was created. Two full-scale polymer composite wing structures were loaded statically, in an upward bending direction, until each wing structure fractured and separated. The wing structures were subsequently examined for the existence of failure characteristics. The examination revealed that whilst characteristics were present, the fragmentation of the structure destroyed valuable evidence. A hypothetical accident scenario utilising the fractured wing structures was developed, which UK government accident investigators subsequently investigated. This provided refinement to the investigative framework and suggested further guidance on the interpretation of polymer composite failures by accident investigators..

Hydrogen storing and electrical properties of hyperbranched polymers-based nanoporous materials

International Nuclear Information System (INIS)

Abdel Rehim, Mona H.; Ismail, Nahla; Badawy, Abd El-Rahman A.A.; Turky, Gamal

2011-01-01

Highlights: · The hydrogen storage capacity of hyperbranched P-Urea, PAMAM and PAMAM and VO x is studied and electrical properties of the samples are also investigated; the measurements showed complete insulating behavior at hydrogenation measuring temperature. These investigations ensure that the polymer conductivity does not play a role in hydrogen uptake, also hyperbranched polymers are promising materials for hydrogen storage. · Electrical properties measurements for the samples showed complete insulating behavior at hydrogenation measuring temperature. · These investigations ensure that the polymer conductivity does not play a role in hydrogen uptake, also hyperbranched polymers are promising materials for hydrogen storage. - Abstract: Hydrogen storage and electrical properties of different hyperbranched polymer systems beside a nanocomposite are studied. The polymers examined are aliphatic hyperbranched poly urea (P-Urea), polyamide amine (PAMAM) and polyamide amine/vanadium oxide (PAMAM/VO x ) nanocomposite. At 80 K and up to 20 bar hydrogen pressure, the hydrogen storage capacity of hyperbranched P-Urea reached 1.6 wt%, 0.9 wt% in case of PAMAM and 0.6 wt% for VO x . The hydrogen storage capacity significantly enhanced when PAMAM and VO x form a nanocomposite and increased up to 2 wt%. At 298 K and up to 20 bar, all the samples did not show measurable hydrogen uptake. Electrical properties of the samples are also investigated; the measurements showed complete insulating behavior at hydrogenation measuring temperature. These investigations ensure that the polymer conductivity does not play a role in hydrogen uptake, also hyperbranched polymers are promising materials for hydrogen storage.

Resonant infrared laser deposition of polymer-nanocomposite materials for optoelectronic applications

Science.gov (United States)

Park, Hee K.; Schriver, Kenneth E.; Haglund, Richard F.

2011-11-01

Polymers find a number of potentially useful applications in optoelectronic devices. These include both active layers, such as light-emitting polymers and hole-transport layers, and passive layers, such as polymer barrier coatings and light-management films. This paper reports the experimental results for polymer films deposited by resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) and resonant infrared pulsed laser deposition (RIR-PLD) for commercial optoelectronic device applications. In particular, light-management films, such as anti-reflection coatings, require refractive-index engineering of a material. However, refractive indices of polymers fall within a relatively narrow range, leading to major efforts to develop both low- and high-refractive-index polymers. Polymer nanocomposites can expand the range of refractive indices by incorporating low- or high-refractive-index nanoscale materials. RIR-MAPLE is an excellent technique for depositing polymer-nanocomposite films in multilayer structures, which are essential to light-management coatings. In this paper, we report our efforts to engineer the refractive index of a barrier polymer by combining RIR-MAPLE of nanomaterials (for example, high refractive-index TiO2 nanoparticles) and RIR-PLD of host polymer. In addition, we report on the properties of organic and polymer films deposited by RIR-MAPLE and/or RIR-PLD, such as Alq3 [tris(8-hydroxyquinoline) aluminum] and PEDOT:PSS [poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate)]. Finally, the challenges and potential for commercializing RIR-MAPLE/PLD, such as industrial scale-up issues, are discussed.

Bioactivity of freeze-dried platelet-rich plasma in an adsorbed form on a biodegradable polymer material.

Science.gov (United States)

Nakajima, Yu; Kawase, Tomoyuki; Kobayashi, Mito; Okuda, Kazuhiro; Wolff, Larry F; Yoshie, Hiromasa

2012-01-01

Owing to the necessity for the immediate preparation from patients' blood, autologous platelet-rich plasma (PRP) limits its clinical applicability. To address this concern and respond to emergency care and other unpredictable uses, we have developed a freeze-dried PRP in an adsorbed form on a biodegradable polymer material (Polyglactin 910). On the polymer filaments of PRP mesh, which was prepared by coating the polymer mesh with human fresh PRP and subsequent freeze-drying, platelets were incorporated, and related growth factors were preserved at high levels. This new PRP mesh preparation significantly and reproducibly stimulated the proliferation of human periodontal ligament cells in vitro and neovascularization in a chorioallantoic membrane assay. A full-thickness skin defect model in a diabetic mouse demonstrated the PRP mesh, although prepared from human blood, substantially facilitated angiogenesis, granulation tissue formation, and re-epithelialization without inducing severe inflammation in vivo. These data demonstrate that our new PRP mesh preparation functions as a bioactive material to facilitate tissue repair/regeneration. Therefore, we suggest that this bioactive material, composed of allogeneic PRP, could be clinically used as a promising alternative in emergency care or at times when autologous PRP is not prepared immediately before application.

Polymers for nuclear materials processing

International Nuclear Information System (INIS)

Jarvinen, G.; Benicewicz, B.; Duke, J.

1996-01-01

This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The use of open-celled microcellular foams as solid sorbents for metal ions and other solutes could provide a revolutionary development in separation science. Macroreticular and gel-bead materials are the current state-of-the-art for solid sorbents to separate metal ions and other solutes from solution. The new polymer materials examined in this effort offer a number of advantages over the older materials that can have a large impact on industrial separations. The advantages include larger usable surface area in contact with the solution, faster sorption kinetics, ability to tailor the uniform cell size to a specific application, and elimination of channeling and packing instability

Photocatalytic activity of PANI loaded coordination polymer composite materials: Photoresponse region extension and quantum yields enhancement via the loading of PANI nanofibers on surface of coordination polymer

International Nuclear Information System (INIS)

Cui, Zhongping; Qi, Ji; Xu, Xinxin; Liu, Lu; Wang, Yi

2013-01-01

To enhance photocatalytic property of coordination polymer in visible light region, polyaniline (PANI) loaded coordination polymer photocatalyst was synthesized through in-situ chemical oxidation of aniline on the surface of coordination polymer. The photocatalytic activity of PANI loaded coordination polymer composite material for degradation of Rhodamine B (RhB) was investigated. Compared with pure coordination polymer photocatalyst, which can decompose RhB merely under UV light irradiation, PANI loaded coordination polymer photocatalyst displays more excellent photocatalytic activity in visible light region. Furthermore, PANI loaded coordination polymer photocatalyst exhibits outstanding stability during the degradation of RhB. - Graphical abstract: PANI loaded coordination polymer composite material, which displays excellent photocatalytic activity under visible light was firstly synthesized through in-situ chemical oxidation of aniline on surface of coordination polymer. Display Omitted - Highlights: • This PANI loaded coordination polymer composite material represents the first conductive polymer loaded coordination polymer composite material. • PANI/coordination polymer composite material displays more excellent photocatalytic activity for the degradation of MO in visible light region. • The “combination” of coordination polymer and PANI will enable us to design high-activity, high-stability and visible light driven photocatalyst in the future

Three dimensional extrusion printing induces polymer molecule alignment and cell organization within engineered cartilage.

Science.gov (United States)

Guo, Ting; Ringel, Julia P; Lim, Casey G; Bracaglia, Laura G; Noshin, Maeesha; Baker, Hannah B; Powell, Douglas A; Fisher, John P

2018-04-16

Proper cell-material interactions are critical to remain cell function and thus successful tissue regeneration. Many fabrication processes have been developed to create microenvironments to control cell attachment and organization on a three-dimensional (3D) scaffold. However, these approaches often involve heavy engineering and only the surface layer can be patterned. We found that 3D extrusion based printing at high temperature and pressure will result an aligned effect on the polymer molecules, and this molecular arrangement will further induce the cell alignment and different differentiation capacities. In particular, articular cartilage tissue is known to have zonal collagen fiber and cell orientation to support different functions, where collagen fibers and chondrocytes align parallel, randomly, and perpendicular, respectively, to the surface of the joint. Therefore, cell alignment was evaluated in a cartilage model in this study. We used small angle X-ray scattering analysis to substantiate the polymer molecule alignment phenomenon. The cellular response was evaluated both in vitro and in vivo. Seeded mesenchymal stem cells (MSCs) showed different morphology and orientation on scaffolds, as a combined result of polymer molecule alignment and printed scaffold patterns. Gene expression results showed improved superficial zonal chondrogenic marker expression in parallel-aligned group. The cell alignment was successfully maintained in the animal model after 7 days with distinct MSC morphology between the casted and parallel printed scaffolds. This 3D printing induced polymer and cell alignment will have a significant impact on developing scaffold with controlled cell-material interactions for complex tissue engineering while avoiding complicated surface treatment, and therefore provides new concept for effective tissue repairing in future clinical applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2018. © 2018 Wiley Periodicals, Inc.

Radiation crosslinking of polymer materials

International Nuclear Information System (INIS)

Yoshii, Fumio

2004-01-01

It was found that some polyfunctional monomers (PFM) like triallyl isocyanurate (TAIC) and trimethallyl isocyanurate (TMAIC) when incorporated at low concentrations, are effective for promotion of crosslinking of biodegradable polymers such as polycaprolactone (PCL), poly(butylene succinate-co-adipate) (PBS) and poly(lactic acid) (PLA). PFM are kneaded with biodegradable polymers at molten condition before irradiation. Radiation crosslinking of PBS and PCL with 1% TAIC gave gel fractions of 80% at 20 kGy. This crosslinking is effective to improve deformation of biodegradable polymers at high temperature. The irradiated materials retained their biodegradability even after crosslinking when subjected to soil burial test. Irradiation at molten state (melting temperature, 340degC) led to crosslinking structures for polytetrafluoroethylene (PTFE). Crosslinked PTFE forms transparent films with high abrasion property and high radiation resistance. High-density polyethylene (HDPE) has a higher gel fraction in irradiation at molten state than irradiation at ordinary temperature. Crosslinked HDPE has been applied as knee joints in order to have high abrasion. Radiation crosslinked polycarbosilane (PCS) fiber gives high heat resistant silicon carbide (SiC) after firing. EB irradiation of PCS is effective to improve strength of product and to inhibit flow during carbonization. SiC, being resistant to high temperature will be applied in turbine and body of rockets. (author)

Structure and Dynamics of Polymer/Polymer grafted nanoparticle composite

Science.gov (United States)

Archer, Lynden

Addition of nanoparticles to polymers is a well-practiced methodology for augmenting various properties of the polymer host, including mechanical strength, thermal stability, barrier properties, dimensional stability and wear resistance. Many of these property changes are known to arise from nanoparticle-induced modification of polymer structure and chain dynamics, which are strong functions of the dispersion state of the nanoparticles' and on their relative size (D) to polymer chain dimensions (e.g. Random coil radius Rg or entanglement mesh size a) . This talk will discuss polymer nanocomposites (PNCs) comprised of Polyethylene Glycol (PEG) tethered silica nanoparticles (SiO2-PEG) dispersed in polymers as model systems for investigating phase stability and dynamics of PNCs. On the basis of small-angle X-ray Scattering, it will be shown that favorable enthalpic interactions between particle-tethered chains and a polymer host provides an important mechanism for creating PNCs in which particle aggregation is avoided. The talk will report on polymer and particle scale dynamics in these materials and will show that grafted nanoparticles well dispersed in a polymer host strongly influence the host polymer relaxation dynamics on all timescales and the polymers in turn produce dramatic changes in the nature (from diffusive to hyperdiffusive) and speed of nano particle decorrelation dynamics at the polymer entanglement threshold. A local viscosity model capable of explaining these observations is discussed and the results compared with scaling theories for NP motions in polymers This material is based on work supported by the National Science Foundation Award Nos. DMR-1609125 and CBET-1512297.

The radiation induced degradation of polymers

International Nuclear Information System (INIS)

Wilski, H.

1987-01-01

A compilation was made of all data about the radiation stability of thermoplastic polymeric materials, published in the literature up to the end of 1985. From those experiments in which the irradiation was carried out in air half value doses (elongation) (= hvd) as a measure of radiation stability were extracted and compared on the basis of the chemical structure of the polymers, the chemical composition of the materials under test and the dose rate, respectively. The first result is that our knowledge of the radiation stability of polymers, if irradiated in air, is still very incomplete. On the other hand enough data were found for some polymers, to see that there is a region at low dose rates where the half value dose Dsub(e) increases with the dose rate (dD/dt) according to the equation Dsub(e)=Dsub(el).(dD/dt)sup(n). This seems to be the normal behavior. Values for the hvd at 1 Gy/h (in air) were found to lie between 1 and 500 kGy (with PTFE and PS at the respective ends of the scale), whereas n varied only between 0.1 and 0.4. The range of validity of the equation and the magnitude of the coefficients strongly depend on the chemical nature of the polymer and also on the kind and amount of the additives used. At dose rates in the neighborhood of 10 5 Gy/h the influence of the dose rate (and the atmosphere) disappears. (author)

Continuous cellularization of calcium phosphate hybrid scaffolds induced by plasma polymer activation

Energy Technology Data Exchange (ETDEWEB)

Bergemann, Claudia [University Medical Center Rostock, Cell Biology, Schillingallee 69, D-18057 Rostock (Germany); Cornelsen, Matthias [University of Rostock, Fluid Technology and Microfluidics, Justus-von-Liebig Weg 6, D-18059 Rostock (Germany); Quade, Antje [Leibniz-Institute for Plasma Science and Technology (INP), Felix-Hausdorff-Str. 2, D-17489 Greifswald (Germany); Laube, Thorsten; Schnabelrauch, Matthias [INNOVENT e.V., Biomaterials Department, Pruessingstrasse 27B, D-07745 Jena (Germany); Rebl, Henrike [University Medical Center Rostock, Cell Biology, Schillingallee 69, D-18057 Rostock (Germany); Weißmann, Volker [Institute for Polymer Technologies (IPT) e.V., Alter Holzhafen 19, D-23966 Wismar (Germany); Seitz, Hermann [University of Rostock, Fluid Technology and Microfluidics, Justus-von-Liebig Weg 6, D-18059 Rostock (Germany); Nebe, Barbara, E-mail: barbara.nebe@med.uni-rostock.de [University Medical Center Rostock, Cell Biology, Schillingallee 69, D-18057 Rostock (Germany)

2016-02-01

The generation of hybrid materials based on β-tricalcium phosphate (TCP) and various biodegradable polymers like poly(L-lactide-co-D,L-lactide) (PLA) represents a common approach to overcoming the disadvantages of pure TCP devices. These disadvantages lie in TCP's mechanical properties, such as brittleness. The positive characteristic of PLA — improvement of compressive strength of calcium phosphate scaffolds – is diametrically opposed to its cell attractiveness. Therefore, the objective of this work was to optimize osteoblast migration and cellularization inside a three-dimensionally (3D) printed, PLA polymer stabilized TCP hybrid scaffold by a plasma polymer process depositing amino groups via allylamine. MG-63 osteoblastic cells inside the 10 mm hybrid scaffold were dynamically cultivated for 14 days in a 3D model system integrated in a perfusion reactor. The whole TCP/PLA hybrid scaffold was continuously colonized due to plasma polymerized allylamine activation inducing the migration potential of osteoblasts. - Highlights: • Mechanical stabilization of β-tricalcium phosphate scaffolds by PLA infiltration • Hybrid scaffolds with higher cell attraction due to plasma polymerized allylamine • 3D perfusion in vitro model for observation of cell migration inside scaffolds • Enhanced cell migration within plasma polymer coated TCP hybrid scaffolds.

Continuous cellularization of calcium phosphate hybrid scaffolds induced by plasma polymer activation

International Nuclear Information System (INIS)

Bergemann, Claudia; Cornelsen, Matthias; Quade, Antje; Laube, Thorsten; Schnabelrauch, Matthias; Rebl, Henrike; Weißmann, Volker; Seitz, Hermann; Nebe, Barbara

2016-01-01

The generation of hybrid materials based on β-tricalcium phosphate (TCP) and various biodegradable polymers like poly(L-lactide-co-D,L-lactide) (PLA) represents a common approach to overcoming the disadvantages of pure TCP devices. These disadvantages lie in TCP's mechanical properties, such as brittleness. The positive characteristic of PLA — improvement of compressive strength of calcium phosphate scaffolds – is diametrically opposed to its cell attractiveness. Therefore, the objective of this work was to optimize osteoblast migration and cellularization inside a three-dimensionally (3D) printed, PLA polymer stabilized TCP hybrid scaffold by a plasma polymer process depositing amino groups via allylamine. MG-63 osteoblastic cells inside the 10 mm hybrid scaffold were dynamically cultivated for 14 days in a 3D model system integrated in a perfusion reactor. The whole TCP/PLA hybrid scaffold was continuously colonized due to plasma polymerized allylamine activation inducing the migration potential of osteoblasts. - Highlights: • Mechanical stabilization of β-tricalcium phosphate scaffolds by PLA infiltration • Hybrid scaffolds with higher cell attraction due to plasma polymerized allylamine • 3D perfusion in vitro model for observation of cell migration inside scaffolds • Enhanced cell migration within plasma polymer coated TCP hybrid scaffolds

Smart Materials for Advanced Applications: Self-Decontaminating Polymers, Photofunctional Composites, and Electroconductive Fibers

Science.gov (United States)

Little, Brian Kevin

2011-12-01

Materials capable of providing multifunctional properties controllable by some external stimulus (pH, light, temperature, etc) are highly desirable and obtainable given recent advancements in material science. Development of these so called "Smart" materials spanned across many disciplines of science with applications in industrial areas such as medical, military, security, and environmental. Furthermore, next-generation materials require the ability to not only sense/respond to changes in their external/internal environment, but process information in regards to these changes and adapt accordingly in a dynamic fashion, autonomously, so called "Intelligent" materials. Findings reported in this manuscript detail the synthesis, characterization, and application of smart materials in the following three areas: (1) self-cleaning polymers (2) photoresponsive composites and (3) electroconductive fibers. Self-Cleaning Polymers: Self-decontaminating polymers are unique materials capable of degrading toxic organic chemicals (TOCs). Barriers composed of or coated with our photochemical reactive polymer matrix could be applied to multiple surfaces for defense against TOCs; for example, military garments for protection against chemical warfare agents. This study investigates conditions necessary for formation of peroxides via O2 reduction induced by long-lived, strongly reducing benzophenyl ketyl (BPK) polymer radicals. Photolysis of aqueous solutions composed of sulphonated poly(ether etherketone), SPEEK, and poly(vinyl alcohol), PVA lead to the formation of the BPK radicals. Experiments investigate the formation and decomposition of peroxides in aqueous solutions of SPEEK/PVA under photolysis. Photofunctional Composites: Photoresponsive nanoporous (PN) films and powders were studied and evaluated as possible additives to sensitize the initiation of CH3NO2 via a mechanism involving coalescence of reaction sites. Such materials consist of a 3-D mesoporous silica framework

Investigating accidents involving aircraft manufactured from polymer composite materials

OpenAIRE

Dunn, Leigh

2013-01-01

This thesis looks into the examination of polymer composite wreckage from the perspective of the aircraft accident investigator. It develops an understanding of the process of wreckage examination as well as identifying the potential for visual and macroscopic interpretation of polymer composite aircraft wreckage. The in-field examination of aircraft wreckage, and subsequent interpretations of material failures, can be a significant part of an aircraft accident investigation. ...

Standard Guide for Testing Polymer Matrix Composite Materials

CERN Document Server

American Society for Testing and Materials. Philadelphia

2011-01-01

1.1 This guide summarizes the application of ASTM standard test methods (and other supporting standards) to continuous-fiber reinforced polymer matrix composite materials. The most commonly used or most applicable ASTM standards are included, emphasizing use of standards of Committee D30 on Composite Materials. 1.2 This guide does not cover all possible standards that could apply to polymer matrix composites and restricts discussion to the documented scope. Commonly used but non-standard industry extensions of test method scopes, such as application of static test methods to fatigue testing, are not discussed. A more complete summary of general composite testing standards, including non-ASTM test methods, is included in the Composite Materials Handbook (MIL-HDBK-17). Additional specific recommendations for testing textile (fabric, braided) composites are contained in Guide D6856. 1.3 This guide does not specify a system of measurement; the systems specified within each of the referenced standards shall appl...

Material Compressing Test of the High Polymer Part Used in Draft Gear of Heavy Load Locomotive

Directory of Open Access Journals (Sweden)

Wei Yangang

2016-01-01

Full Text Available According to the actual load cases of heavy load locomotive, the material compressing tests of the high polymer parts used in the locomotive are researched. The relationship between stress and strain during the material compressing are acquired by means of comparing the many results of the material compressing tests under different test condition. The relationship between stress and strain during the material compressing is nonlinear in large range of strain, but the relationship is approximately linear in small range of strain. The material of the high polymer made in China and the material of the high polymer imported are compared through the tests. The results show that the compressing property of the material of the high polymer made in China and the material of the high polymer imported are almost same. The research offers the foundation to study the structure elasticity of the draft gear.

Polymer-induced liquid precursor (PILP) phases of calcium carbonate formed in the presence of synthetic acidic polypeptides - relevance to biomineralization

NARCIS (Netherlands)

Schenk, A.S.; Zope, H.; Kim, Y.; Kros, A.; Sommerdijk, N.A.J.M.; Meldrum, F.C.

2012-01-01

Polymer-induced liquid precursor (PILP) phases of calcium carbonate have attracted significant interest due to possible applications in materials synthesis, and their resemblance to intermediates seen in biogenic mineralisation processes. Further, these PILP phases have been formed in vitro using

Advanced materials and processes for polymer solar cell devices

DEFF Research Database (Denmark)

Petersen, Martin Helgesen; Søndergaard, Roar; Krebs, Frederik C

2010-01-01

The rapidly expanding field of polymer and organic solar cells is reviewed in the context of materials, processes and devices that significantly deviate from the standard approach which involves rigid glass substrates, indium-tin-oxide electrodes, spincoated layers of conjugated polymer/fullerene...... be performing less than the current state-of-the-art in their present form but that may have the potential to outperform these pending a larger investment in effort....

Vacuum ultraviolet photochemistry of polymers

International Nuclear Information System (INIS)

Skurat, Vladimir

2003-01-01

The interaction of vacuum UV radiation (wavelength range from 1 to 200 nm) with polymers is interesting for fundamental and applied sciences. This interest is stimulated by various reasons: - Wide applications of polymeric materials in semiconductor technology, where they are used as photoresist materials in combination with VUV light sources (lasers, excimer lamps, synchrotron radiation and others). - Polymers are widely used as spacecraft materials in the last 20 years. On near-Earth orbits, the polymeric materials of spacecraft surfaces are destroyed by solar radiation. - VUV radiation is one of the components of gas discharge plasmas, which are used for treatment of polymer, with the aim of modifying their surface properties. The main features of interaction of VUV radiation with polymers are discussed. The spectra of intrinsic absorption of saturated polymers (polyethylene, polypropylene, polytetrafluoroethylene and others) are situated mainly in the VUV region. The photochemistry of polymers in the VUV region is very different from their photochemistry at wavelengths longer than 200 nm, where the absorption spectra belong to impurities and polymer defects. The polymer photochemistry in the VUV region is wavelength-dependent. At wavelengths longer than about 140 nm, the main role is played by transformations of primary-formed singlet excited molecules. At shorter wavelengths the role of photoionization increases progressively and the main features of VUV photolysis become similar to the picture of radiolysis, with significant contributions of charge pairs and triplet excited molecules. Very important features of VUV light absorption in polymers are high absorption coefficients. Because of this, the surface layers absorb large doses of energy. This leads to very profound transformation of material on the polymer surface. In particular for polymers which are considered destroyed by radiation (for example, perfluoropolymers), this leads to VUV-induced erosion

Three-Dimensional (3D) Printing of Polymer-Metal Hybrid Materials by Fused Deposition Modeling.

Science.gov (United States)

Fafenrot, Susanna; Grimmelsmann, Nils; Wortmann, Martin; Ehrmann, Andrea

2017-10-19

Fused deposition modeling (FDM) is a three-dimensional (3D) printing technology that is usually performed with polymers that are molten in a printer nozzle and placed line by line on the printing bed or the previous layer, respectively. Nowadays, hybrid materials combining polymers with functional materials are also commercially available. Especially combinations of polymers with metal particles result in printed objects with interesting optical and mechanical properties. The mechanical properties of objects printed with two of these metal-polymer blends were compared to common poly (lactide acid) (PLA) printed objects. Tensile tests and bending tests show that hybrid materials mostly containing bronze have significantly reduced mechanical properties. Tensile strengths of the 3D-printed objects were unexpectedly nearly identical with those of the original filaments, indicating sufficient quality of the printing process. Our investigations show that while FDM printing allows for producing objects with mechanical properties similar to the original materials, metal-polymer blends cannot be used for the rapid manufacturing of objects necessitating mechanical strength.

Fracture mechanics of polymer mortar made with recycled raw materials

Directory of Open Access Journals (Sweden)

Marco Antonio Godoy Jurumenha

2010-12-01

Full Text Available The aim of this work is to show that industrial residues could be used in construction applications so that production costs as well as environmental protection can be improved. The fracture properties of polymer mortar manufactured with recycled materials are investigated to evaluate the materials behaviour to crack propagation. The residues used in this work were spent sand from foundry industry as aggregate, unsaturated polyester resin from polyethylene terephthalate (PET as matrix and polyester textile fibres from garment industry, producing an unique composite material fully from recycled components with low cost. The substitution of fresh by used foundry sand and the insertions of textile fibres contribute to a less brittle behaviour of polymer mortar.

A new system for crack closure of cementitious materials using shrinkable polymers

International Nuclear Information System (INIS)

Jefferson, Anthony; Joseph, Christopher; Lark, Robert; Isaacs, Ben; Dunn, Simon; Weager, Brendon

2010-01-01

This paper presents details of an original crack-closure system for cementitious materials using shrinkable polymer tendons. The system involves the incorporation of unbonded pre-oriented polymer tendons in cementitious beams. Crack closure is achieved by thermally activating the shrinkage mechanism of the restrained polymer tendons after the cement-based material has undergone initial curing. The feasibility of the system is demonstrated in a series of small scale experiments on pre-cracked prismatic mortar specimens. The results from these tests show that, upon activation, the polymer tendon completely closes the preformed macro-cracks and imparts a significant stress across the crack faces. The potential of the system to enhance the natural autogenous crack healing process and generally improve the durability of concrete structures is addressed.

Nanocomposite polymer materials used in radioprotection

International Nuclear Information System (INIS)

Cherestes, Codrut; Cherestes, Margareta; Constantinescu, Livia

2004-01-01

A thermoplastic polymer-tungsten composite has been developed with characteristics that preserve the performance attributes of Pb (good radiation absorption, easy of forming, etc.) while avoiding its toxicity. This poly-metal composite formed primarily of tungsten and polymeric resins can be used in a wide range of applications in which lead and other toxic heavy metals have been historically applied. With density equal to that of Pb, the new material offers greater yield strength than Pb, can be injection molded, is nontoxic, and can be formulated to be very flexible or very stiff, depending on the application. With a large applicability in radiation shielding for nuclear medicine, radiology and nuclear power, the new material represents an ecologically sound alternative to toxic, environmentally undesirable traditional materials. The properties of the new material, its applications and its characteristics relative to Pb will be examined. (authors)

Hybrid waste filler filled bio-polymer foam composites for sound absorbent materials

Science.gov (United States)

Rus, Anika Zafiah M.; Azahari, M. Shafiq M.; Kormin, Shaharuddin; Soon, Leong Bong; Zaliran, M. Taufiq; Ahraz Sadrina M. F., L.

2017-09-01

Sound absorption materials are one of the major requirements in many industries with regards to the sound insulation developed should be efficient to reduce sound. This is also important to contribute in economically ways of producing sound absorbing materials which is cheaper and user friendly. Thus, in this research, the sound absorbent properties of bio-polymer foam filled with hybrid fillers of wood dust and waste tire rubber has been investigated. Waste cooking oil from crisp industries was converted into bio-monomer, filled with different proportion ratio of fillers and fabricated into bio-polymer foam composite. Two fabrication methods is applied which is the Close Mold Method (CMM) and Open Mold Method (OMM). A total of four bio-polymer foam composite samples were produce for each method used. The percentage of hybrid fillers; mixture of wood dust and waste tire rubber of 2.5 %, 5.0%, 7.5% and 10% weight to weight ration with bio-monomer. The sound absorption of the bio-polymer foam composites samples were tested by using the impedance tube test according to the ASTM E-1050 and Scanning Electron Microscope to determine the morphology and porosity of the samples. The sound absorption coefficient (α) at different frequency range revealed that the polymer foam of 10.0 % hybrid fillers shows highest α of 0.963. The highest hybrid filler loading contributing to smallest pore sizes but highest interconnected pores. This also revealed that when highly porous material is exposed to incident sound waves, the air molecules at the surface of the material and within the pores of the material are forced to vibrate and loses some of their original energy. This is concluded that the suitability of bio-polymer foam filled with hybrid fillers to be used in acoustic application of automotive components such as dashboards, door panels, cushion and etc.

Radiation crosslinking of polymer materials and its functional properties

International Nuclear Information System (INIS)

Yoshii, Fumio

2006-01-01

It was found out that radiation crosslinking of biodegradable polymer such as poly (butylene succinate, PBS) and poly(ε-caprolactone, PCL) could be achieved by radiation in the presence of small amount of trimethallyl isocyanurate (TMAIC) or 1% triallyl isocyanurate (TAIC). Such modification is very effective to improve heat resistance for PBS and PCL. Poly (lactic acid, PLA) undergoes crosslinking effectively with 3% TAIC by radiation. Outstanding feature of these polymers is their biodegradability even after crosslinking. Radiation crosslinking of polysaccharide derivatives such as carboxymethyl-cellulose (CMC) is also achieved in aqueous solution at high concentration (paste-like state). The crosslinking behavior was largely affected by the degree of substitution (DS) and polymer concentration. After removal of water the dry CMC gel is used as water absorbent material. This dry gel is the most effective for removal of large amounts of water from organic wastes, resulting in the acceleration of their fermentation. Measurement of swelling ratio of the dry CMC gel in 0.9% NaCl aqueous solution was carried out to expand application fields for this material. Radiation crosslinked poly (vinyl alcohol) hydrogel was successfully commercialized from July 2004 as wound dressing for accelerated healing. Furthermore, this material was also used as gel protector to prevent shore sore and was further commercialized. (author)

A study on the improvement of radiation-induced oxidation resistance for polypropylene and PVC materials

International Nuclear Information System (INIS)

Park, K. Z.; Jeong, K. S.; Cho, S. H.; Cho, Y. H.; Seok, H. C.

2002-01-01

The object of this project is to improve the stability and the economics by reducing the radiation-induced oxidation as a factor of degradation of polymer materials used under the radiation environment. In order to attain the objective of this study and to check the effect of diamond-like carbon (DLC) coating on the anti-oxidation reaction, polymer specimens such as Polyproplyene, PVC coating DLC thin layer were exposed to high level gamma radiation, and their irradiation effects were investigated. A plasma-enhanced chemical vapor deposition method was adopted in fabricating a DLC thin film on the polymer specimens, which were irradiated with the non-DLC film deposited specimens under the gamma radiation emitted from Co-60 source from 1 x 10 5 to 1 x 10 8 rads exposure. According to the characterization of irradiated specimens from the elapsed time of minimum 4 hours to a maximum of 105 days after the irradiation, the DLC deposition on the polymer surface was revealed to contribute to the improvement on the resistance of the radiation-induced oxidation in this study

Using Rouse-Fowler model to describe radiation-induced electrical conductivity of nanocomposite materials

Science.gov (United States)

Dyuryagina, N. S.; Yalovets, A. P.

2017-05-01

Using the Rouse-Fowler (RF) model this work studies the radiation-induced electrical conductivity of a polymer nanocomposite material with spherical nanoparticles against the intensity and exposure time of gamma-ray, concentration and size of nanoparticles. The research has found the energy distribution of localized statesinduced by nanoparticles. The studies were conducted on polymethylmethacrylate (PMMA) with CdS nanoparticles.

Light-induced second-order nonlinear optical properties of molecular materials

International Nuclear Information System (INIS)

Fiorini, Celine

1995-01-01

We present a theoretical and experimental study of all-optical orientation. The work focusses more particularly on the realization of poled polymers for quadratic nonlinear optics. It is shown that the coherent superposition of two beams at fundamental and second harmonic frequencies results in the breaking of the former centro-symmetry of the material. The source is a Neodymium-YAG laser delivering 25 ps pulses at 1064 nm. The incident second-harmonic beam is obtained by frequency doubling in a KDP crystal. Using a phase conjugation configuration based on six-wave mixing interactions, we have Investigated in detail the mechanism of photo-induced second-harmonic generation in initially centrosymmetric materials. It is shown that the light-induced non-centro-symmetry is due to an orientational hole burning of the molecules. The process involves interference effects between one and two photon absorptions. Experiments are performed in various solutions of an azo-dye molecule (Disperse Red One). The possibility of inducing quasi-permanent second-order susceptibility in a PMMA polymer matrix doped with the azo-dye molecule of Disperse Red One is also demonstrated. The method of all-optical poling consists in a seeding type process with alternate writing and probing phases. Permanent orientation of the molecules can be described in terms of photo-isomerization processes. It leads to a poling of the molecules with a spatial modulation which is phase-matched for frequency doubling. Relevant parameters leading to an efficient polarisation of the sample are identified. A theoretical modelling of the different phenomena observed is proposed. Last part of the study is devoted to an enlarged study of the potentialities offered by this dual-frequency holography technique: orientation of octupolar molecules, polarisation of highly transparent materials. We also show that the new techniques developed during this work can also reveal to be complementary methods for nonlinear

Light-induced antibacterial activity of electrospun chitosan-based material containing photosensitizer

Energy Technology Data Exchange (ETDEWEB)

Severyukhina, A.N., E-mail: severyuhina_alexandra@mail.ru [Institute of Nanostructures and Biosystems, Saratov State University, 410012 Saratov (Russian Federation); Petrova, N.V.; Yashchenok, A.M. [Institute of Nanostructures and Biosystems, Saratov State University, 410012 Saratov (Russian Federation); Bratashov, D.N. [Institute of Nanostructures and Biosystems, Saratov State University, 410012 Saratov (Russian Federation); Department of Nano- and Biomedical Technologies, Saratov State University, 410012 Saratov (Russian Federation); Smuda, K. [Institute of Transfusion Medicine, Charité-Universitätsmedizin, 10117 Berlin (Germany); Mamonova, I.A. [Institute of Traumatology and Orthopedics, 410002 Saratov (Russian Federation); Yurasov, N.A. [Institute of Nanostructures and Biosystems, Saratov State University, 410012 Saratov (Russian Federation); Puchinyan, D.M. [Institute of Nanostructures and Biosystems, Saratov State University, 410012 Saratov (Russian Federation); Institute of Traumatology and Orthopedics, 410002 Saratov (Russian Federation); Georgieva, R. [Institute of Transfusion Medicine, Charité-Universitätsmedizin, 10117 Berlin (Germany); Department of Medical Physics, Biophysics and Radiology, Medical Faculty, Trakia University, 6000 Stara Zagora (Bulgaria); Bäumler, H. [Institute of Transfusion Medicine, Charité-Universitätsmedizin, 10117 Berlin (Germany); Lapanje, A. [Institute of Nanostructures and Biosystems, Saratov State University, 410012 Saratov (Russian Federation); Josef Stefan Institute, 1000 Ljubljana (Slovenia); Gorin, D.A. [Institute of Nanostructures and Biosystems, Saratov State University, 410012 Saratov (Russian Federation); Department of Nano- and Biomedical Technologies, Saratov State University, 410012 Saratov (Russian Federation)

2017-01-01

Increasing antimicrobial resistance requires the development of novel materials and approaches for treatment of various infections. Utilization of photodynamic therapy represents an advanced alternative to antibiotics and metal-based agents. Here, we report the fabrication of electrospun material that possesses benefits of both topical antimicrobial and photodynamic therapies. This material combines chitosan, as a biocompatible polymer, and a second generation photosensitizer. The incorporation of photosensitizer doesn't affect the material morphology and its nearly uniform distribution in fibers structure was observed by confocal Raman microscopy. Owing to photosensitizer the prepared material exhibits the light-induced and spatially limited antimicrobial activity that was demonstrated against Staphylococcus aureus, an important etiological infectious agent. Such material can be potentially used in antibacterial therapy of chronic wounds, infections of diabetic ulcers, and burns, as well as rapidly spreading and intractable soft-tissue infections caused by resistant bacteria. - Highlights: • Chitosan with a phthalocyanine photosensitizer was electrospun into fibers. • Photosensitizer was uniformly distributed in the electrospun material. • The incorporation of photosensitizer does not affect the fiber morphology. • Chitosan/photosensitizer composites possess light-induced antibacterial activity. • The antibacterial activity of the material is limited to the area of irradiation.

Oxygen ion implantation induced microstructural changes and electrical conductivity in Bakelite RPC detector material

Energy Technology Data Exchange (ETDEWEB)

Kumar, K. V. Aneesh, E-mail: aneesh1098@gmail.com; Ravikumar, H. B., E-mail: hbr@physics.uni-mysore.ac.in [Department of Studies in Physics, University of Mysore, Mysore-570006 (India); Ranganathaiah, C., E-mail: cr@physics.uni-mysore.ac.in [Govt. Research Centre, Sahyadri Educational Institutions, Mangalore-575007 (India); Kumarswamy, G. N., E-mail: kumy79@gmail.com [Department of Studies in Physics, Amrita Vishwa Vidyapeetham, Bangalore-560035 (India)

2016-05-06

In order to explore the structural modification induced electrical conductivity, samples of Bakelite Resistive Plate Chamber (RPC) detector materials were exposed to 100 keV Oxygen ion in the fluences of 10{sup 12}, 10{sup 13}, 10{sup 14} and 10{sup 15} ions/cm{sup 2}. Ion implantation induced microstructural changes have been studied using Positron Annihilation Lifetime Spectroscopy (PALS) and X-Ray Diffraction (XRD) techniques. Positron lifetime parameters viz., o-Ps lifetime and its intensity shows the deposition of high energy interior track and chain scission leads to the formation of radicals, secondary ions and electrons at lower ion implantation fluences (10{sup 12} to10{sup 14} ions/cm{sup 2}) followed by cross-linking at 10{sup 15} ions/cm{sup 2} fluence due to the radical reactions. The reduction in electrical conductivity of Bakelite detector material is correlated to the conducting pathways and cross-links in the polymer matrix. The appropriate implantation energy and fluence of Oxygen ion on polymer based Bakelite RPC detector material may reduce the leakage current, improves the efficiency, time resolution and thereby rectify the aging crisis of the RPC detectors.

Development of nanocomposite polymer materials for electrical and electronic applications

International Nuclear Information System (INIS)

Chine, Bruno

2007-01-01

Some results and experimental procedures of laboratory are reported in the frame of researches conducted for the development of new nanostructured composite materials. These new materials, which are constituted by an organic phase: the polymer and an inorganic phase: the silicate, are being strongly investigated nowadays so it is expected that they could provide, among other, better electrical insulation properties and flame-delay in electrical and electronic applications. The laboratory experimental work has been developed from two families of polymers, thermoplastics and thermosets and clays silicates providing lamellar type. There are now some preliminary results, such as obtaining thin films of these nanocomposite materials, their complete characterization by X-ray diffraction, scanning microscopy and thermogravimetric analysis, they do well to wait for future research activities. (author) [es

Induced helical backbone conformations of self-organizable dendronized polymers.

Science.gov (United States)

Rudick, Jonathan G; Percec, Virgil

2008-12-01

information to rationalize function as retrostructural analysis. Retrostructural analysis validates our hypothesis that the self-assembling dendrons induce a helical backbone conformation in cylindrical self-organizable dendronized polymers. This helical conformation mediates unprecedented functions. Self-organizable dendronized polymers have emerged as powerful building blocks for nanoscience by virtue of their dimensions and ability to self-organize. Discrete cylindrical and spherical structures with well-defined dimensions can be visualized and manipulated individually. More importantly, they provide a robust framework for elucidating functions available only at the nanoscale. This Account will highlight structures and functions generated from self-organizable dendronized polymers that enable integration of the nanoworld with its macroscopic universe. Emphasis is placed on those structures and functions derived from the induced helical backbone conformation of cylindrical self-organizable dendronized polymers.

Three-Dimensional (3D Printing of Polymer-Metal Hybrid Materials by Fused Deposition Modeling

Directory of Open Access Journals (Sweden)

Susanna Fafenrot

2017-10-01

Full Text Available Fused deposition modeling (FDM is a three-dimensional (3D printing technology that is usually performed with polymers that are molten in a printer nozzle and placed line by line on the printing bed or the previous layer, respectively. Nowadays, hybrid materials combining polymers with functional materials are also commercially available. Especially combinations of polymers with metal particles result in printed objects with interesting optical and mechanical properties. The mechanical properties of objects printed with two of these metal-polymer blends were compared to common poly (lactide acid (PLA printed objects. Tensile tests and bending tests show that hybrid materials mostly containing bronze have significantly reduced mechanical properties. Tensile strengths of the 3D-printed objects were unexpectedly nearly identical with those of the original filaments, indicating sufficient quality of the printing process. Our investigations show that while FDM printing allows for producing objects with mechanical properties similar to the original materials, metal-polymer blends cannot be used for the rapid manufacturing of objects necessitating mechanical strength.

Polymer-Ceramic Composite Materials for Pyroelectric Infrared Detectors: An Overview

Science.gov (United States)

Aggarwal, M. D; Currie, J. R.; Penn, B. G.; Batra, A. K.; Lal, R. B.

2007-01-01

Ferroelectrics:Polymer composites can be considered an established substitute for conventional electroceramics and ferroelectric polymers. The composites have a unique blend of polymeric properties such as mechanical flexibility, high strength, formability, and low cost, with the high electro-active properties of ceramic materials. They have attracted considerable interest because of their potential use in pyroelectric infrared detecting devices and piezoelectric transducers. These flexible sensors and transducers may eventually be useful for their health monitoring applications for NASA crew launch vehicles and crew exploration vehicles being developed. In the light of many technologically important applications in this field, it is worthwhile to present an overview of the pyroelectric infrared detector theory, models to predict dielectric behavior and pyroelectric coefficient, and the concept of connectivity and fabrication techniques of biphasic composites. An elaborate review of Pyroelectric-Polymer composite materials investigated to date for their potential use in pyroelectric infrared detectors is presented.

Ion induced modification of polymers at energies between 100 keV and 1 GeV applied for optical waveguides and improved metal adhesion

International Nuclear Information System (INIS)

Rueck, D.M.

2000-01-01

Polymers are a class of materials widely used for a broad field of applications. Ion irradiation ranging from several eV to GeV is a quite efficient tool to modify the properties of polymers like wettability, optical properties, adhesion between metal and polymer surfaces. In this paper ion induced chemical changes of polymers will be discussed in relation to the modified macroscopic properties. In the field of optical telecommunication, polymers are discussed as a new class of materials for the fabrication of passive optical devices. Ion irradiation is a promising method to generate structures with a modified index of refraction, which is necessary for the guidance of light with different wavelengths in optical devices. Modified optical properties of different polymers under ion irradiation will be discussed. Analytical investigations like infrared measurements and measurement of the outgassing reaction products during irradiation will be discussed to interpret the chemical changes of the polymers. Metallization of polymers is of interest in several fields of application like for multilayer systems in microtechnology or casings for radiation shielding for example. Ion beam mixing at low energies is a promising method to improve the metal/polymer adhesion. Also ion irradiation at high energies applied to a metal/polymer multilayer can improve the adhesion of a metal layer to a polymer surface, if not sufficient. Different metal/polymer systems will be presented as well as specific applications

Effect that radiation exerts to insulation breakdown of heat resistant polymer materials

International Nuclear Information System (INIS)

Fujita, Shigetaka; Baba, Makoto; Noto, Fumitoshi; Ruike, Mitsuo.

1990-01-01

Artificial satellites are always exposed to cosmic rays which contain the radiations which do not reach the ground, therefore, the radiation resistance of the polymer insulators for cables and others used in such environment becomes a problem. Also the polymer insulator materials used for nuclear facilities require excellent radiation resistance. It is important to examine the effect that radiation exerts to electric insulation characteristics from the viewpoint of material development. In this paper, the insulation breakdown characteristics of heat resistant polymer films and the mini-cables made for trial of heat resistant polymer materials in the case without irradiation and in the case of gamma ray irradiation, and the results of the structural analysis are reported. The specimens tested, the experimental method and the results are described. The insulation breakdown strength of PFA and FEP films lowered from 0.15-0.2 MGy, but that of PEEK film did not change up to 5 MGy. It was found that fluorine group resins were apt to deteriorate by oxidation as dose increased. (K.I.)

Particle localization and hyperuniformity of polymer-grafted nanoparticle materials

Energy Technology Data Exchange (ETDEWEB)

Chremos, Alexandros [Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD (United States); Douglas, Jack F.

2017-05-15

The properties of materials largely reflect the degree and character of the localization of the molecules comprising them so that the study and characterization of particle localization has central significance in both fundamental science and material design. Soft materials are often comprised of deformable molecules and many of their unique properties derive from the distinct nature of particle localization. We study localization in a model material composed of soft particles, hard nanoparticles with grafted layers of polymers, where the molecular characteristics of the grafted layers allow us to ''tune'' the softness of their interactions. Soft particles are particular interesting because spatial localization can occur such that density fluctuations on large length scales are suppressed, while the material is disordered at intermediate length scales; such materials are called ''disordered hyperuniform''. We use molecular dynamics simulation to study a liquid composed of polymer-grafted nanoparticles (GNP), which exhibit a reversible self-assembly into dynamic polymeric GNP structures below a temperature threshold, suggesting a liquid-gel transition. We calculate a number of spatial and temporal correlations and we find a significant suppression of density fluctuations upon cooling at large length scales, making these materials promising for the practical fabrication of ''hyperuniform'' materials. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Glass interface effect on high-strain-rate tensile response of a soft polyurethane elastomeric polymer material

NARCIS (Netherlands)

Fan, J.T.; Weerheijm, J.; Sluys, L.J.

2015-01-01

The glass interface effect on dynamic tensile response of a soft polyurethane elastomeric polymer material has been investigated by subjecting a glass-polymer system of this polymer material matrix embedded a single 3 mm-diameter glass particle to impact loading in a split Hopkinson tension bar

Gamma Radiation Induced Preparation of Functional Conducting Polymer Hollow Spheres

Energy Technology Data Exchange (ETDEWEB)

Lee, K. -P.; Gopalan, A. I.; Philips, M. F.; Jeong, K.M., E-mail: kplee@knu.ac.kr [Department of Chemistry Education, Teacher' s College, Kyungpook National University 1370, Sankyuk-dong, Buk-gu, Daegu 702-701 (Korea, Republic of)

2010-07-01

New materials are sought for applications in many of the emerging fields that include catalysis, sensors, biomedical, optics and electronic application. With the advent of nanotechnology, innovative materials with novel properties are being synthesized towards target applications. Changing the sizes of particles, chemical, optical, and mechanical properties of the materials can often be tailored according to the specific needs of the application. Nanocrystalline, nanoparticles, nanocapsules, nanoporous materials, nanofibers, nanowires, fullerenes, nanotubes, nanosprings, nanobelts, dendrimers and nanospheres, ets, are few of the nanostructured materials. The examples of nanostructured materials include semiconducting nanowire quantum dots for gas sensing and self-assembled flower-like architectures. Self-assembly of nanoparticles can result in specific structures with unique and useful electronic, optical, and magnetic properties. Self or induced assemby of simple nanoparticles and rods could result into complex geometries, such as nanoflowers, binary superlattices, optical grating. Over the past decade, hollow spherical nanomaterials have received considerable attention due to their interesting properties such as low density, high surface area and good permeation. Various methods like solvothermal, self-assembly, sonochemical, solvent evaporation, chemical vapor deposition, microwave-assisted aqueous hydrothermal and electrochemical are being pursued for the production of hollow spherical materials. Polymer capsules and hollow spheres have increasingly received interest because of their large surface area and potential applications in catalysis, controlled delivery, artificial cells, light fillers and photonics.

Gamma Radiation Induced Preparation of Functional Conducting Polymer Hollow Spheres

International Nuclear Information System (INIS)

Lee, K.-P.; Gopalan, A.I.; Philips, M.F.; Jeong, K.M.

2010-01-01

New materials are sought for applications in many of the emerging fields that include catalysis, sensors, biomedical, optics and electronic application. With the advent of nanotechnology, innovative materials with novel properties are being synthesized towards target applications. Changing the sizes of particles, chemical, optical, and mechanical properties of the materials can often be tailored according to the specific needs of the application. Nanocrystalline, nanoparticles, nanocapsules, nanoporous materials, nanofibers, nanowires, fullerenes, nanotubes, nanosprings, nanobelts, dendrimers and nanospheres, ets, are few of the nanostructured materials. The examples of nanostructured materials include semiconducting nanowire quantum dots for gas sensing and self-assembled flower-like architectures. Self-assembly of nanoparticles can result in specific structures with unique and useful electronic, optical, and magnetic properties. Self or induced assemby of simple nanoparticles and rods could result into complex geometries, such as nanoflowers, binary superlattices, optical grating. Over the past decade, hollow spherical nanomaterials have received considerable attention due to their interesting properties such as low density, high surface area and good permeation. Various methods like solvothermal, self-assembly, sonochemical, solvent evaporation, chemical vapor deposition, microwave-assisted aqueous hydrothermal and electrochemical are being pursued for the production of hollow spherical materials. Polymer capsules and hollow spheres have increasingly received interest because of their large surface area and potential applications in catalysis, controlled delivery, artificial cells, light fillers and photonics

Non-destructive evaluation of porosity and its effect on mechanical properties of carbon fiber reinforced polymer composite materials

Science.gov (United States)

Bhat, M. R.; Binoy, M. P.; Surya, N. M.; Murthy, C. R. L.; Engelbart, R. W.

2012-05-01

In this work, an attempt is made to induce porosity of varied levels in carbon fiber reinforced epoxy based polymer composite laminates fabricated using prepregs by varying the fabrication parameters such as applied vacuum, autoclave pressure and curing temperature. Different NDE tools have been utilized to evaluate the porosity content and correlate with measurable parameters of different NDE techniques. Primarily, ultrasonic imaging and real time digital X-ray imaging have been tried to obtain a measurable parameter which can represent or reflect the amount of porosity contained in the composite laminate. Also, effect of varied porosity content on mechanical properties of the CFRP composite materials is investigated through a series of experimental investigations. The outcome of the experimental approach has yielded interesting and encouraging trend as a first step towards developing an NDE tool for quantification of effect of varied porosity in the polymer composite materials.

Thick film laser induced forward transfer for deposition of thermally and mechanically sensitive materials

International Nuclear Information System (INIS)

Kattamis, Nicholas T.; Purnick, Priscilla E.; Weiss, Ron; Arnold, Craig B.

2007-01-01

Laser forward transfer processes incorporating thin absorbing films can be used to deposit robust organic and inorganic materials but the deposition of more delicate materials has remained elusive due to contamination and stress induced during the transfer process. Here, we present the approach to high resolution patterning of sensitive materials by incorporating a thick film polymer absorbing layer that is able to dissipate shock energy through mechanical deformation. Multiple mechanisms for transfer as a function of incident laser energy are observed and we show viable and contamination-free deposition of living mammalian embryonic stem cells

Polymer reinforcement of cement systems

International Nuclear Information System (INIS)

Swamy, R.N.

1979-01-01

In the last couple of decades several cement- and concrete-based composites have come into prominence. Of these, cement-polymer composites, like cement-fibre composites, have been recognised as very promising, and considerable research and development on their properties, fabrication methods and application are in progress. Of the three types of concrete materials which incorporate polymers to form composites, polymer impregnated concrete forms a major development in which hardened concrete is impregnated with a liquid monomer which is subsequently polymerized to form a rigid polymer network in the pores of the parent material. In this first part of the extensive review of the polymer reinforcement of cement systems, the process technology of the various monomer impregnation techniques and the properties of the impregnated composite are assessed critically. It is shown that the high durability and superior performance of polymer impregnated concrete can provide an economic and competitive alternative in in situ strengthening, and in other areas where conventional concrete can only at best provide adequate performance. The review includes a section on radiation-induced polymerization. (author)

Swift heavy ion induced modification of aliphatic polymers

Energy Technology Data Exchange (ETDEWEB)

Hossain, Umme Habiba

2015-01-15

In this thesis, the high energy heavy ion induced modification of aliphatic polymers is studied. Two polymer groups, namely polyvinyl polymers (PVF, PVAc, PVA and PMMA) and fluoropolymers (PVDF, ETFE, PFA and FEP) were used in this work. Polyvinyl polymers were investigated since they will be used as insulating materials in the superconducting magnets of the new ion accelerators of the planned International Facility for Antiproton and Ion Research (FAIR) at the GSI Helmholtz-Centre of Heavy Ion Research (GSI) in Darmstadt. In order to study ion-beam induced degradation, all polymer foils were irradiated at the GSI linear accelerator UNILAC using several projectiles (U, Au, Sm, Xe) and experimentation sites (beam lines X0 and M3) over a large fluence regime (1 x 10{sup 10} - 5 x 10{sup 12} ions/cm{sup 2}). Five independent techniques, namely infrared (FT-IR) and ultraviolet-visible (UV-Vis) spectroscopy, residual gas analysis (RGA), thermal gravimetric analysis (TGA), and mass loss analysis (ML), were used to analyze the irradiated samples. FT-IR spectroscopy revealed that ion irradiation led to the decrease of characteristic band intensities showing the general degradation of the polymers, with scission of side groups and the main backbone. As a consequence of the structural modification, new bands appeared. UV-Vis transmission analysis showed an absorption edge shift from the ultraviolet region towards the visible region indicating double bond and conjugated double bond formation. On-line massspectrometric residual gas analysis showed the release of small gaseous fragment molecules. TGA analysis gave evidence of a changed thermal stability. With ML analysis, the considerable mass loss was quantified. The results of the five complementary analytical methods show how heavy ion irradiation changes the molecular structure of the polymers. Molecular degradation mechanisms are postulated. The amount of radiation damage is found to be sensitive to the used type of ionic

Radiation Processed Materials in Products from Polymers for Agricultural Applications

International Nuclear Information System (INIS)

2014-07-01

This publication results from a technical meeting on radiation processed materials in products from polymers for agricultural applications, which was held from 8 to 12 July 2013 at the IAEA in Vienna. The meeting provided a forum for the sharing of practical experiences and lessons learned, and reviewed the recent developments in the use of radiation technologies for the preparation of environmental friendly products based on polymers for agricultural applications

Radiation Processed Materials in Products from Polymers for Agricultural Applications

Energy Technology Data Exchange (ETDEWEB)

NONE

2014-07-15

This publication results from a technical meeting on radiation processed materials in products from polymers for agricultural applications, which was held from 8 to 12 July 2013 at the IAEA in Vienna. The meeting provided a forum for the sharing of practical experiences and lessons learned, and reviewed the recent developments in the use of radiation technologies for the preparation of environmental friendly products based on polymers for agricultural applications.

Accelerated Aging of Polymer Composite Bridge Materials

Energy Technology Data Exchange (ETDEWEB)

Carlson, Nancy Margaret; Blackwood, Larry Gene; Torres, Lucinda Laine; Rodriguez, Julio Gallardo; Yoder, Timothy Scott

1999-03-01

Accelerated aging research on samples of composite material and candidate ultraviolet (UV) protective coatings is determining the effects of six environmental factors on material durability. Candidate fastener materials are being evaluated to determine corrosion rates and crevice corrosion effects at load-bearing joints. This work supports field testing of a 30-ft long, 18-ft wide polymer matrix composite (PMC) bridge at the Idaho National Engineering and Environmental Laboratory (INEEL). Durability results and sensor data from tests with live loads provide information required for determining the cost/benefit measures to use in life-cycle planning, determining a maintenance strategy, establishing applicable inspection techniques, and establishing guidelines, standards, and acceptance criteria for PMC bridges for use in the transportation infrastructure.

Inorganic-organic hybrid polymer for preparation of affiliating material using electron beam irradiation

International Nuclear Information System (INIS)

Chung, Jaeseung; Kim, Seongeun; Kim, Byounggak; Lee, Jongchan; Park, Jihyun; Lee, Byeongcheol

2011-01-01

Recently, silver nano materials have gained a lot of attentions in a variety of applications due to the unique biological, optical, and electrical properties. Especially, the antifouling property of these material is considered to be an important character for biomedical field, marine coatings industry, biosensor, and drug delivery. In this study, we design and synthesize the inorganic-organic hybrid polymer for preparation of affiliating materials. Silver nano materials having antifouling property with different shapes are prepared by control the electron beam irradiation conditions. Inorganic-organic hybrid polymer was synthesized and characterized. → Morphology and size controlled nano materials are prepared using electron beam irradiation. → Silver nano materials having various shapes can be used for antifouling material

Use of radiation-induced polymers in cement slurries

International Nuclear Information System (INIS)

Knight, B.L.; Rhudy, J.S.; Gogarty, W.B.

1976-01-01

Water loss from cement slurries is reduced by incorporating within a cement slurry a polymer obtained as a product of radiation-induced polymerization of acrylamide and/or methacrylamide and acrylic acid, methacrylic acid, and/or alkali metal salts thereof. The polymerization is preferably carried out in 10-60 percent aqueous monomer solution with gamma radiation. The aqueous monomer solution preferably contains 25-99 percent acrylamide and 75-1 percent sodium acrylate. The polymer can be present in concentration of about 0.001 to about 3.0 weight percent, based on the aqueous phase of the slurry

Atomic layer deposition on polymer based flexible packaging materials: Growth characteristics and diffusion barrier properties

International Nuclear Information System (INIS)

Kaeaeriaeinen, Tommi O.; Maydannik, Philipp; Cameron, David C.; Lahtinen, Kimmo; Johansson, Petri; Kuusipalo, Jurkka

2011-01-01

One of the most promising areas for the industrial application of atomic layer deposition (ALD) is for gas barrier layers on polymers. In this work, a packaging material system with improved diffusion barrier properties has been developed and studied by applying ALD on flexible polymer based packaging materials. Nanometer scale metal oxide films have been applied to polymer-coated papers and their diffusion barrier properties have been studied by means of water vapor and oxygen transmission rates. The materials for the study were constructed in two stages: the paper was firstly extrusion coated with polymer film, which was then followed by the ALD deposition of oxide layer. The polymers used as extrusion coatings were polypropylene, low and high density polyethylene, polylactide and polyethylene terephthalate. Water vapor transmission rates (WVTRs) were measured according to method SCAN-P 22:68 and oxygen transmission rates (O 2 TRs) according to a standard ASTM D 3985. According to the results a 10 nm oxide layer already decreased the oxygen transmission by a factor of 10 compared to uncoated material. WVTR with 40 nm ALD layer was better than the level currently required for most common dry flexible packaging applications. When the oxide layer thickness was increased to 100 nm and above, the measured WVTRs were limited by the measurement set up. Using an ALD layer allowed the polymer thickness on flexible packaging materials to be reduced. Once the ALD layer was 40 nm thick, WVTRs and O 2 TRs were no longer dependent on polymer layer thickness. Thus, nanometer scale ALD oxide layers have shown their feasibility as high quality diffusion barriers on flexible packaging materials.

Atomic layer deposition on polymer based flexible packaging materials: Growth characteristics and diffusion barrier properties

Energy Technology Data Exchange (ETDEWEB)

Kaeaeriaeinen, Tommi O., E-mail: tommi.kaariainen@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Maydannik, Philipp, E-mail: philipp.maydannik@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Cameron, David C., E-mail: david.cameron@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Lahtinen, Kimmo, E-mail: kimmo.lahtinen@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland); Johansson, Petri, E-mail: petri.johansson@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland); Kuusipalo, Jurkka, E-mail: jurkka.kuusipalo@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland)

2011-03-01

One of the most promising areas for the industrial application of atomic layer deposition (ALD) is for gas barrier layers on polymers. In this work, a packaging material system with improved diffusion barrier properties has been developed and studied by applying ALD on flexible polymer based packaging materials. Nanometer scale metal oxide films have been applied to polymer-coated papers and their diffusion barrier properties have been studied by means of water vapor and oxygen transmission rates. The materials for the study were constructed in two stages: the paper was firstly extrusion coated with polymer film, which was then followed by the ALD deposition of oxide layer. The polymers used as extrusion coatings were polypropylene, low and high density polyethylene, polylactide and polyethylene terephthalate. Water vapor transmission rates (WVTRs) were measured according to method SCAN-P 22:68 and oxygen transmission rates (O{sub 2}TRs) according to a standard ASTM D 3985. According to the results a 10 nm oxide layer already decreased the oxygen transmission by a factor of 10 compared to uncoated material. WVTR with 40 nm ALD layer was better than the level currently required for most common dry flexible packaging applications. When the oxide layer thickness was increased to 100 nm and above, the measured WVTRs were limited by the measurement set up. Using an ALD layer allowed the polymer thickness on flexible packaging materials to be reduced. Once the ALD layer was 40 nm thick, WVTRs and O{sub 2}TRs were no longer dependent on polymer layer thickness. Thus, nanometer scale ALD oxide layers have shown their feasibility as high quality diffusion barriers on flexible packaging materials.

Shadowgraphy investigation of laser-induced forward transfer: Front side and back side ablation of the triazene polymer sacrificial layer

International Nuclear Information System (INIS)

Fardel, Romain; Nagel, Matthias; Nueesch, Frank; Lippert, Thomas; Wokaun, Alexander

2009-01-01

Thin films of a photodecomposible triazene polymer are used as sacrificial layer for the micro-deposition of sensitive materials by laser-induced forward transfer. To understand the ablation process of this sacrificial layer, the ultraviolet laser ablation of triazene films was investigated by time-resolved shadowgraphy. Irradiation from the film side shows a complete decomposition into gaseous fragments, while ablation through the substrate causes ejection of a solid flyer of polymer. The occurence of the flyer depends on the film thickness as well as on the applied fluence, and a compact flyer is obtaind when these two parameters are optimized

Polymers Containing Diphenylvinyl-Substituted Indole Rings as Charge-Transporting Materials for OLEDs

Science.gov (United States)

Grigalevicius, S.; Zostautiene, R.; Sipaviciute, D.; Stulpinaite, B.; Volyniuk, D.; Grazulevicius, J. V.; Liu, L.; Xie, Z.; Zhang, B.

2016-02-01

Monomers and polymers containing electronically isolated diphenylvinyl-substituted indole rings were synthesized and characterized by nuclear magnetic resonance (NMR) and mass spectroscopies as well as by gel permeation chromatography. The polymers represent amorphous materials with glass transition temperatures of 91-109°C and thermal decomposition starting above 307°C. Electron photoemission spectra of thin films of the synthesized polymers revealed ionization potentials of 5.54-5.58 eV. The synthesized polymers were tested as hole-transporting materials in simple electroluminescent organic light-emitting diode (OLED) devices with tris(quinolin-8-olato)aluminium (Alq3) as an emitter as well as an electron-transporting layer. A green OLED device containing a hole-transporting layer of poly[1-(2,3-epithiopropyl)-2-methyl-3-(2,2-diphenylvinyl)índole] exhibited the best overall performance with a driving voltage of 4.0 V, maximum photometric efficiency of 2.8 cd/A and maximum brightness of about 4200 cd/m2.

Reducing burn-in voltage loss in polymer solar cells by increasing the polymer crystallinity

KAUST Repository

Heumueller, Thomas; Mateker, William R.; Sachs-Quintana, I. T.; Vandewal, Koen; Bartelt, Jonathan A.; Burke, Timothy M.; Ameri, Tayebeh; Brabec, Christoph J.; McGehee, Michael D.

2014-01-01

In order to commercialize polymer solar cells, the fast initial performance losses present in many high efficiency materials will have to be managed. This burn-in degradation is caused by light-induced traps and its characteristics depend on which

Biodegraded polymers as materials for sowing of grain crops seeds

Directory of Open Access Journals (Sweden)

L. S. Shibryaeva

2015-01-01

Full Text Available Increase of efficiency of grain production, solution of problems of food security demand search and development of innovative technologies at all stages. One of ways of environmentally friendly production is sowing of seeds on an excipient located in the soil, for example, nonwoven fabric made of eco- decomposable decomposed biodegraded polymer. Biodegraded polymeric materials influence on sowing properties of grain crops seeds and provide realization of their potential productivity. The authors used an electroforming method with chloroform and a dichloroethane application to receive nonwoven fabric from poly-3-hydroxybutyrate (PHB and its compositions together with synthetic nitrile rubber (PHB-SNR. Polymeric material influences on energy of germination and viability of wheat seeds. Germination index is calculated, heat physical parameters are determined for the polymeric excipient. The major factor influencing seeds germination is a structure of nonwoven fabric. Water diffusion, its supply to seeds and their viability depend on morphological features of polymeric material. Polymer excipient structure influence on speed of development of root system on which, in turn, intensity of destruction of polymer depends. The best indicators of energy of germination and viability of seeds correspond to the greatest value of decrease of melting heat of PHB in mix PHB-SNR. In addition, among the studied samples of PHB-SNR the material received from blend of solvents is most effective. The cause is in feature of its structure favorable for a seed germination.

Resin bond to indirect composite and new ceramic/polymer materials: a review of the literature.

Science.gov (United States)

Spitznagel, Frank A; Horvath, Sebastian D; Guess, Petra C; Blatz, Markus B

2014-01-01

Resin bonding is essential for clinical longevity of indirect restorations. Especially in light of the increasing popularity of computer-aided design/computer-aided manufacturing-fabricated indirect restorations, there is a need to assess optimal bonding protocols for new ceramic/polymer materials and indirect composites. The aim of this article was to review and assess the current scientific evidence on the resin bond to indirect composite and new ceramic/polymer materials. An electronic PubMed database search was conducted from 1966 to September 2013 for in vitro studies pertaining the resin bond to indirect composite and new ceramic/polymer materials. The search revealed 198 titles. Full-text screening was carried out for 43 studies, yielding 18 relevant articles that complied with inclusion criteria. No relevant studies could be identified regarding new ceramic/polymer materials. Most common surface treatments are aluminum-oxide air-abrasion, silane treatment, and hydrofluoric acid-etching for indirect composite restoration. Self-adhesive cements achieve lower bond strengths in comparison with etch-and-rinse systems. Thermocycling has a greater impact on bonding behavior than water storage. Air-particle abrasion and additional silane treatment should be applied to enhance the resin bond to laboratory-processed composites. However, there is an urgent need for in vitro studies that evaluate the bond strength to new ceramic/polymer materials. This article reviews the available dental literature on resin bond of laboratory composites and gives scientifically based guidance for their successful placement. Furthermore, this review demonstrated that future research for new ceramic/polymer materials is required. © 2014 Wiley Periodicals, Inc.

Printable polymer actuators from ionic liquid, soluble polyimide, and ubiquitous carbon materials.

Science.gov (United States)

Imaizumi, Satoru; Ohtsuki, Yuto; Yasuda, Tomohiro; Kokubo, Hisashi; Watanabe, Masayoshi

2013-07-10

We present here printable high-performance polymer actuators comprising ionic liquid (IL), soluble polyimide, and ubiquitous carbon materials. Polymer electrolytes with high ionic conductivity and reliable mechanical strength are required for high-performance polymer actuators. The developed polymer electrolytes comprised a soluble sulfonated polyimide (SPI) and IL, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C2mim][NTf2]), and they exhibited acceptable ionic conductivity up to 1 × 10(-3) S cm(-1) and favorable mechanical properties (elastic modulus >1 × 10(7) Pa). Polymer actuators based on SPI/[C2mim][NTf2] electrolytes were prepared using inexpensive activated carbon (AC) together with highly electron-conducting carbon such as acetylene black (AB), vapor grown carbon fiber (VGCF), and Ketjen black (KB). The resulting polymer actuators have a trilaminar electric double-layer capacitor structure, consisting of a polymer electrolyte layer sandwiched between carbon electrode layers. Displacement, response speed, and durability of the actuators depended on the combination of carbons. Especially the actuators with mixed AC/KB carbon electrodes exhibited relatively large displacement and high-speed response, and they kept 80% of the initial displacement even after more than 5000 cycles. The generated force of the actuators correlated with the elastic modulus of SPI/[C2mim][NTf2] electrolytes. The displacement of the actuators was proportional to the accumulated electric charge in the electrodes, regardless of carbon materials, and agreed well with the previously proposed displacement model.

Electric field induced dewetting at polymer/polymer interfaces

NARCIS (Netherlands)

Lin, Z.Q.; Kerle, T.; Russell, T.P.; Schäffer, E.; Steiner, U

2002-01-01

External electric fields were used to amplify interfacial fluctuations in the air/polymer/polymer system where one polymer dewets the other. Two different hydrodynamic regimes were found as a function of electric field strength. If heterogeneous nucleation leads to the formation of holes before the

Creep-induced anisotropy in covalent adaptable network polymers.

Science.gov (United States)

Hanzon, Drew W; He, Xu; Yang, Hua; Shi, Qian; Yu, Kai

2017-10-11

Anisotropic polymers with aligned macromolecule chains exhibit directional strengthening of mechanical and physical properties. However, manipulating the orientation of polymer chains in a fully cured thermoset is almost impossible due to its permanently crosslinked nature. In this paper, we demonstrate that rearrangeable networks with bond exchange reactions (BERs) can be utilized to tailor the anisotropic mechanical properties of thermosetting polymers. When a constant force is maintained at BER activated temperatures, the malleable thermoset creeps in the direction of stress, and macromolecule chains align themselves in the same direction. The aligned polymer chains result in an anisotropic network with a stiffer mechanical behavior in the direction of creep, while with a more compliant behavior in the transverse direction. The degree of network anisotropy is proportional to the amount of creep strain. A multi-length scale constitutive model is developed to study the creep-induced anisotropy of thermosetting polymers. The model connects the micro-scale BER kinetics, orientation of polymer chains, and directional mechanical properties of network polymers. Without any fitting parameters, it is able to predict the evolution of creep strain at different temperatures and anisotropic stress-strain behaviors of CANs after creep. Predictions on the chain orientation are verified by molecular dynamics (MD) simulation. Based on parametric studies, it is shown that the influences of creep time and temperature on the network anisotropy can be generalized into a single parameter, and the evolution of directional modulus follows an Arrhenius type time-temperature superposition principle (TTSP). The presented work provides a facile approach to transform isotropic thermosets into anisotropic ones using simple heating, and their directional properties can be readily tailored by the processing conditions.

College-Mentored Polymer/Materials Science Modules for Middle and High School Students

Science.gov (United States)

Lorenzini, Robert G.; Lewis, Maurica S.; Montclare, Jin Kim

2011-01-01

Polymers are materials with vast environmental and economic ramifications, yet are generally not discussed in secondary education science curricula. We describe a program in which college mentors develop and implement hands-on, polymer-related experiments to supplement a standard, state regents-prescribed high school chemistry course, as well as a…

Nanomaterials for Polymer Electrolyte Membrane Fuel Cells; Materials Challenges Facing Electrical Energy Storate

Energy Technology Data Exchange (ETDEWEB)

Gopal Rao, MRS Web-Editor; Yury Gogotsi, Drexel University; Karen Swider-Lyons, Naval Research Laboratory

2010-08-05

Symposium T: Nanomaterials for Polymer Electrolyte Membrane Fuel Cells Polymer electrolyte membrane (PEM) fuel cells are under intense investigation worldwide for applications ranging from transportation to portable power. The purpose of this seminar is to focus on the nanomaterials and nanostructures inherent to polymer fuel cells. Symposium topics will range from high-activity cathode and anode catalysts, to theory and new analytical methods. Symposium U: Materials Challenges Facing Electrical Energy Storage Electricity, which can be generated in a variety of ways, offers a great potential for meeting future energy demands as a clean and efficient energy source. However, the use of electricity generated from renewable sources, such as wind or sunlight, requires efficient electrical energy storage. This symposium will cover the latest material developments for batteries, advanced capacitors, and related technologies, with a focus on new or emerging materials science challenges.

Fluorinated Polymers as Smart Materials for Advanced Biomedical Applications

Directory of Open Access Journals (Sweden)

Vanessa F. Cardoso

2018-02-01

Full Text Available Fluorinated polymers constitute a unique class of materials that exhibit a combination of suitable properties for a wide range of applications, which mainly arise from their outstanding chemical resistance, thermal stability, low friction coefficients and electrical properties. Furthermore, those presenting stimuli-responsive properties have found widespread industrial and commercial applications, based on their ability to change in a controlled fashion one or more of their physicochemical properties, in response to single or multiple external stimuli such as light, temperature, electrical and magnetic fields, pH and/or biological signals. In particular, some fluorinated polymers have been intensively investigated and applied due to their piezoelectric, pyroelectric and ferroelectric properties in biomedical applications including controlled drug delivery systems, tissue engineering, microfluidic and artificial muscle actuators, among others. This review summarizes the main characteristics, microstructures and biomedical applications of electroactive fluorinated polymers.

Ionizing radiation effect on physico-mechanical characteristics of thermoplastic polymer materials

International Nuclear Information System (INIS)

Stankevich, V.M.; Pleskachevsky, Yu.M.; Smirnov, V.V.

2001-01-01

Investigation results in the field of ionizing radiation effect on structure and physico-mechanical properties of novel polymer materials are presented. The materials under study are various grades of PETP, PA-6 and polyethylene concentrate of technical carbon (PECC) commercially produced and extensively used in Belarus and abroad. It has been proved using EPR, thermomechanical and gel analyses that a combined effect of ionizing radiation within 0 to 10 MGy of absorbed dose range under different concentrations of mineral fillers (TiO 2 , kaolin, carbon black, graphite) and intensive cross-linking processes in amorphous phase are able to considerably improve strength characteristics of the studied polymers and their compositions. Most informative parameter was found to be breaking strength at rapture (σ r ) which enables to estimate the character of ionizing effect on the targets. At 0.01-0.05 MGy absorbed dose the highest σ r was shown as compared to initial PETP by the following materials: PN grade - 9 times, D - two and a half. When absorbed dose of PETP reached 0.2 MGy, σ r of PN surpassed the initial material 7.8 times, that of D - by 30% and E - by 1,5%. This is the evidence of elevated resistance of named materials to ionizing radiation in contrast to non-filled PETP 215. Growth of σ r in PA-6 has been noticed at absorbed dose above 2 MGy in response to maximum gel-formation values. Abrupt reduction of the studied parameters of PP upon irradiation is attributed to its destruction. Domination of cross-linking processes has been observed in PEVP and PECC which reduces macromolecular mobility and elasticity of the material as a whole but promotes polymer strengthening. Drop of PEVP impact strength can be related to its embrittlement. Presence of the filler (carbon black) in PECC at the initial stage of exposure resulted in improvement of studied parameters. Their further impairment is the result of limited mobility of macromolecules owing to cross-linking in

The use of radiation-induced graft polymerization for modification of polymer track membranes

International Nuclear Information System (INIS)

Shtanko, N.I.; Kabanov, V.Ya.; Apel, P.Yu.; Yoshida, M.

1999-01-01

Track membranes (TM) made of poly(ethylene terephtalate) (PET) and polypropylene (PP) films have a number of peculiarities as compared with other ones. They have high mechanical strength at a low thickness, narrow pore size distribution, low content of extractables. However, TM have some disadvantages such as low chemical resistance in alkaline media (PET TM), the low water flow rate due to the hydrophobic nature of their surface. The use of radiation-induced graft polymerization makes it possible to improve the basic characteristics of TM. In this communication our results on the modification of PET and PP TM are presented. The modified membranes were prepared by radiation-induced graft polymerization from the liquid phase. Three methods of grafting were used: (a) the direct method in argon atmosphere; (b) the pre-irradiation of TM in air followed by grafting in argon atmosphere; (c) pre-irradiation in vacuum followed by grafting in vacuum without contacting oxygen. The aim of the work was to investigate some properties of TM modified by grafted poly(methylvinyl pyridine) (PMVP) and poly(N-isopropylacrylamide) (PNIPAAM). It was shown that the modification of TM with hydrophilic polymer results in the growth of the water flow rate. In the past few years many works have been devoted to the synthesis of new polymers - the so-called 'intelligent' materials - such as PNIPAAM. However, it is very difficult to make thin membranes of this polymer. Recently, it has been proposed to manufacture composite membranes by grafting stimulus-responsive polymers onto TM. Following this principle, we prepared thermosensitive membranes by the radiation-induced graft polymerization of N-isopropylacrylamide (NIPAAM) onto PET TM. PET TM with the pore size of about 1 μm and pore density of 10 6 cm -2 were first inserted into a solution of NIPAAM containing inhibitor of homopolymerization (CuCl 2 ) and then exposed to the γ-rays from a 60 Co source. The transport properties of the

The use of radiation-induced graft polymerization for modification of polymer track membranes

Science.gov (United States)

Shtanko, N. I.; Kabanov, V. Ya.; Apel, P. Yu.; Yoshida, M.

1999-05-01

Track membranes (TM) made of poly(ethylene terephtalate) (PET) and polypropylene (PP) films have a number of peculiarities as compared with other ones. They have high mechanical strength at a low thickness, narrow pore size distribution, low content of extractables. However, TM have some disadvantages such as low chemical resistance in alkaline media (PET TM), the low water flow rate due to the hydrophobic nature of their surface. The use of radiation-induced graft polymerization makes it possible to improve the basic characteristics of TM. In this communication our results on the modification of PET and PP TM are presented. The modified membranes were prepared by radiation-induced graft polymerization from the liquid phase. Three methods of grafting were used: (a) the direct method in argon atmosphere; (b) the pre-irradiation of TM in air followed by grafting in argon atmosphere; (c) pre-irradiation in vacuum followed by grafting in vacuum without contacting oxygen. The aim of the work was to investigate some properties of TM modified by grafted poly(methylvinyl pyridine) (PMVP) and poly(N-isopropylacrylamide) (PNIPAAM). It was shown that the modification of TM with hydrophilic polymer results in the growth of the water flow rate. In the past few years many works have been devoted to the synthesis of new polymers - the so-called "intelligent" materials - such as PNIPAAM. However, it is very difficult to make thin membranes of this polymer. Recently, it has been proposed to manufacture composite membranes by grafting stimulus-responsive polymers onto TM. Following this principle, we prepared thermosensitive membranes by the radiation-induced graft polymerization of N-isopropylacrylamide (NIPAAM) onto PET TM. PET TM with the pore size of about 1 μm and pore density of 10 6 cm -2 were first inserted into a solution of NIPAAM containing inhibitor of homopolymerization (CuCl 2) and then exposed to the γ-rays from a 60Co source. The transport properties of the grafted

Mass spectrometric comparison of swift heavy ion-induced and anaerobic thermal degradation of polymers

Science.gov (United States)

Lima, V.; Hossain, U. H.; Walbert, T.; Seidl, T.; Ensinger, W.

2018-03-01

The study of polymers irradiated by highly energetic ions and the resulting radiation-induced degradation is of major importance for space and particle accelerator applications. The mechanism of ion-induced molecular fragmentation of polyethylene, polyethyleneimine and polyamide was investigated by means of mass spectrometry and infrared spectroscopy. The results show that the introduction of nitrogen and oxygen into the polymer influences the stability rendering aliphatic polymers with heteroatoms less stable. A comparison to thermal decomposition data from literature reveals that ion-induced degradation is different in its bond fracture mechanism. While thermal degradation starts at the weakest bond, which is usually the carbon-heteroatom bond, energetic ion irradiation leads in the first step to scission of all types of bonds creating smaller molecular fragments. This is due to the localized extreme energy input under non-equilibrium conditions when the ions transfer kinetic energy onto electrons. These findings are of relevance for the choice of polymers for long-term application in both space and accelerator facilities.

Fabrication of a reinforced polymer microstructure using femtosecond laser material processing

International Nuclear Information System (INIS)

Alubaidy, M; Venkatakrishnan, K; Tan, B

2010-01-01

This paper presents a new method for the formation of microfeatures with reinforced polymer using femtosecond laser material processing. The femtosecond laser was used for the generation of a three-dimensional interweaved nanofiber and the construction of microfeatures, such as microchannels and voxels, through two-photon polymerization of a nanofiber-dispersed polymer resin. This new method has the potential of direct fabrication of reinforced micro/nanostructures.

New approach to design of ceramic/polymer material compounds

International Nuclear Information System (INIS)

Todt, A; Nestler, D; Trautmann, M; Wagner, G

2016-01-01

The damage tolerance of carbon fibre-reinforced ceramic-matrix composite materials depends on their porosity and can be rather significant. Complex structures are difficult to produce. The integration of simple geometric structures of ceramic-matrix composite materials in complex polymer-based hybrid structures is a possible approach of realising those structures. These hybrid material compounds, produced in a cost-efficient way, combine the different advantages of the individual components in one hybrid material compound. In addition the individual parts can be designed to fit a specific application and the resulting forces. All these different advantages result in a significant reduction of not only the production costs and the production time, but also opens up new areas of application, such as the large-scale production of wear-resistant and chemically inert, energy dampening components for reactors or in areas of medicine. The low wettability of the ceramic component however is a disadvantage of this approach. During the course of this contribution, different C/C composite materials with a specific porosity were produced, while adjusting the resin/hardening agent-ratio, as well as the processing parameters. After the production, different penetration tests were conducted with a polymer component. The final part of the article is comprised of the microstructural analysis and the explanation of the mechanical relationships. (paper)

Development of polymer hybrid materials and analyzing techniques for their depletions

International Nuclear Information System (INIS)

Takaya, Haruo; Kobayashi, Yoshinori; Hirata, Koichi; Nakahara, Hisae; Kinugasa, Shinichi; Kamiya, Yoshinori

1999-01-01

The purpose of this research project was to develop new methods for evaluation and analysis of deterioration of polymer materials under radiological environment and its complicated environment including chemical effects. Furthermore, a screening and development for new radio-resistant polymer materials were attempted. In 1996, the third year of this project, the effects of γ-ray exposure on cardo-type polymers, novel high performance molecules were investigated and the early radiochemical changes due to the exposure were studied according to measurement of the life-time of cation. Cardo-type polymers were exposed to γ-ray and the changes in the molecular size and its distribution were analyzed by size exclusion chromatography and multi-angle laser light scattering (SEC/MALLS). Two cardo-type polymers, PI-BP and PA-T were used as the test subjects and polystyrene was as the standard control. Three membranes made from these three polymers were exposed to γ-ray at 0.2-1.2 MGy. The exposed membranes were applied onto SEC/MALLS after dissolving in NMP. The molecular weight of PI-BP was decreased as an increase of the radiation dose and there appeared a peak in a low molecular range when exposed at higher than 0.4 MGy. The molecular weight was decreased depending to the dose for all of the two cardo-type polymers and the control polystyrene sample. The ratio, Mw/Mn for PI-BP was decreased as an increase of the dose, whereas the ratio for PA-T was hardly changed by the exposure. On the contrary, the ratio for the polystyrene sample was greatly changed as an increase of the dose. These results suggest that various molecular-sized chains were produced by the exposure from the molecule, of which size was mono-dispersed before the exposure. (M.N.)

A facile route to ketene-functionalized polymers for general materials applications

Science.gov (United States)

Leibfarth, Frank A.; Kang, Minhyuk; Ham, Myungsoo; Kim, Joohee; Campos, Luis M.; Gupta, Nalini; Moon, Bongjin; Hawker, Craig J.

2010-03-01

Function matters in materials science, and methodologies that provide paths to multiple functionality in a single step are to be prized. Therefore, we introduce a robust and efficient strategy for exploiting the versatile reactivity of ketenes in polymer chemistry. New monomers for both radical and ring-opening metathesis polymerization have been developed, which take advantage of Meldrum's acid as both a synthetic building block and a thermolytic precursor to dialkyl ketenes. The ketene-functionalized polymers are directly detected by their characteristic infrared absorption and are found to be stable under ambient conditions. The inherent ability of ketenes to provide crosslinking via dimerization and to act as reactive chemical handles via addition, provides simple methodology for application in complex materials challenges. Such versatile characteristics are illustrated by covalently attaching and patterning a dye through microcontact printing. The strategy highlights the significant opportunities afforded by the traditionally neglected ketene functional group in polymer chemistry.

Multi-functionalized side-chain supramolecular polymers: A methodology towards tunable functional materials

Science.gov (United States)

Nair, Kamlesh Prabhakaran

Even as we see a significant growth in the field of supramolecular polymers in the last ten years, multi-functionalized systems have been scarcely studied. Noncovalent multi-functionalization provides unique advantages such as rapid materials optimization via reversible functionalization as well as for the tuning of materials properties by exploiting the differences in the nature of these reversible interactions. This thesis involves the design principles, synthesis & methodology of supramolecular side-chain multi-functionalized polymers. The combination of a functionally tolerant & controlled polymerization technique such as ROMP with multiple noncovalent interactions such as hydrogen bonding, metal coordination and ionic interactions has been successfully used to synthesize these polymers. Furthermore, the orthogonality between the above interactions in block/random copolymers has been studied in detail. It has been found that the studied interactions were orthogonal to each other. To validate the viability of this methodology using multiple orthogonal interactions towards materials design noncovalent crosslinking of polymers has been used as a potential application. Three classes of networks have been studied: complementary multiple hydrogen bonded networks, metal crosslinked networks, & multi-functionalized hydrogen bonded and metal coordinated networks. The first room temperature decrosslinking by exclusive complementary hydrogen bonded interactions has been successfully achieved. Furthermore network properties have been successfully tuned by varying the network micro-structure which in turn was tuned by the hydrogen bonding motifs used for inter-chain crosslinking. By combining two different noncovalent interactions used for inter-chain crosslinking, it was possible to make multi-functionalized materials whose properties could be controlled by varying the crosslinking strategy. Hence by employing multi-functionalization methodology, important materials

Dynamic compressive mechanical response of a soft polymer material

NARCIS (Netherlands)

Fan, J.T.; Weerheijm, J.; Sluys, L.J.

2015-01-01

The dynamic mechanical behaviour of a soft polymer material (Clear Flex 75) was studied using a split Hopkinson pressure bar (SHPB) apparatus. Mechanical properties have been determined at moderate to high strain rates. Real time deformation and fracture were recorded using a high-speed camera.

Application of polymer nanocomposite materials in food packaging

Directory of Open Access Journals (Sweden)

Amra Odobašić

2015-01-01

Full Text Available The term “nano” refers to nano particle size from 1 to 100 nanometers. The term "nanotechnology" was first introduced by Norio Taniguchi in 1974. Nanotechnology may be used to improve the taste and texture of food and for the production of packaging that maintain fresh product. The primary function of packaging is to maintain the quality and safety of products during transport and storage period, as well as to extend its viability by preventing unwanted effect agents such as microorganisms, chemical contaminants, oxygen, moisture and light. The aim of this paper is to point out the achievements of nanotechnology in terms of food packaging with an overview of polymers that are commonly used in food packaging, as well as strategies to improve the physical properties of polymers, including mechanical strength, thermal stability and barrier to gases. By studing of recently published literature, it was clear that nanomaterials such as nano polymers are trying to replace conventional materials in food packaging. Nanosensors can be used to prove the presence of contaminants, microtoxins and microorganisms in food.

Kinetics of radiation-induced structural alterations in electron-irradiated polymer-based composites

International Nuclear Information System (INIS)

Zaikin, Yu.A.; Potanin, A.S.; Koztaeva, U.P.

2002-01-01

Complete text of publication follows. In our previous studies measurements of internal friction temperature dependence were used for characterization of thermally activated and radiation-induced structural evolution in different types of polymer-based composites. This paper supplements these measurements with kinetic studies of internal friction (IF) parameters and EPR signals in a glass-cloth epoxy-filled laminate ST-ETF after electron irradiation up to doses of 1-10 MGy. Experiment have shown that the lifetime of free radicals in this composite considerably exceeds the characteristic time of molecular structural rearrangement due to scission and cross-linking after irradiation, as determined from IF measurements. This result is explained by slow proceeding of sterically hindered disproportionation reactions that stabilize the end groups of the macro-chain disrupt during irradiation and finally fix the act of scission. A mathematical model is formulated for description of structural evolution and alterations of IF parameters in polymer-based composites during and after electron irradiation. The description is based on the track model of radiation damage in polymers and phenomenological theory of radiation-induced structural transformations. General description does not give details of radiation-chemical conversion in different structural components of composites but indicates the direction of their structural evolution. In the model considered a composite material was divided into three parts (binder, filler, and a boundary layer). It was supposed that after primary distribution of radiation energy radiation-chemical conversion proceeds independently in each of these regions. It was also suggested that all the radical reactions were of the second order. On the example of glass-cloth laminate ST-ETF it is shown that this model allows to describe alterations in composite structural characteristics during irradiation and in the course of their self-organization after

Development of Biomedical Polymer-Silicate Nanocomposites: A Materials Science Perspective

Directory of Open Access Journals (Sweden)

Chia-Jung Wu

2010-04-01

Full Text Available Biomedical polymer-silicate nanocomposites have potential to become critically important to the development of biomedical applications, ranging from diagnostic and therapeutic devices, tissue regeneration and drug delivery matrixes to various bio-technologies that are inspired by biology but have only indirect biomedical relation. The fundamental understanding of polymer-nanoparticle interactions is absolutely necessary to control structure-property relationships of materials that need to work within the chemical, physical and biological constraints required by an application. This review summarizes the most recent published strategies to design and develop polymer-silicate nanocomposites (including clay based silicate nanoparticles and bioactive glass nanoparticles for a variety of biomedical applications. Emerging trends in bio-technological and biomedical nanocomposites are highlighted and potential new fields of applications are examined.

Relaxation induced optical anisotropy during dynamic overshoot swelling of zwitterionic polymer films

NARCIS (Netherlands)

Ogieglo, Wojciech; de Grooth, Joris; Wormeester, Herbert; Wessling, Matthias; Nijmeijer, Dorothea C.; Benes, Nieck Edwin

2013-01-01

In-situ spectroscopic ellipsometry was used to investigate the swelling behavior of thin supported zwitterionic polymers based on sulfobetaine methacrylate and n-butylacrylate. This material represents an interesting class of zwitterionic polymers, with large potential in reduction of biofouling of

Concentrated Light for Accelerated Photo Degradation of Polymer Materials

DEFF Research Database (Denmark)

Madsen, Morten Vesterager; Tromholt, Thomas; Norrman, Kion

2013-01-01

Concentrated light is used to perform photochemical degradation of polymer solar cell materials with acceleration factors up to 1200. At constant temperature the photon efficiency in regards to photo degradation is constant for 1–150 suns and oxygen diffusion rates are not a limiting factor...

Shock wave emission from laser-induced cavitation bubbles in polymer solutions.

Science.gov (United States)

Brujan, Emil-Alexandru

2008-09-01

The role of extensional viscosity on the acoustic emission from laser-induced cavitation bubbles in polymer solutions and near a rigid boundary is investigated by acoustic measurements. The polymer solutions consist of a 0.5% polyacrylamide (PAM) aqueous solution with a strong elastic component and a 0.5% carboxymethylcellulose (CMC) aqueous solution with a weak elastic component. A reduction of the maximum amplitude of the shock wave pressure and a prolongation of the oscillation period of the bubble were found in the elastic PAM solution. It might be caused by an increased resistance to extensional flow which is conferred upon the liquid by the polymer additive. In both polymer solutions, however, the shock pressure decays proportionally to r(-1) with increasing distance r from the emission centre.

Nano-Particle Enhanced Polymer Materials for Space Flight Applications

Science.gov (United States)

Criss, Jim M., Jr.; Powell, William D.; Connell, John W.; Stallworth-Bordain, Yemaya; Brown, Tracy R.; Mintz, Eric A.; Schlea, Michelle R.; Shofne, Meisha L.

2009-01-01

Recent advances in materials technology both in polymer chemistry and nano-materials warrant development of enhanced structures for space flight applications. This work aims to develop spacecraft structures based on polymer matrix composites (PMCs) that utilize these advancements.. Multi-wall carbon nano-tubes (MWCNTs) are expected ·to increase mechanical performance, lower coefficient of thermal expansion (CTE), increase electrical conductivity (mitigate electrostatic charge), increase thermal conductivity, and reduce moisture absorption of the resultant space structures. In this work, blends of MWCNTs with PETI-330 were prepared and characterized. The nano-reinforced resins were then resin transfer molded (RTM) into composite panels using M55J carbon fabric and compared to baseline panels fabricated from a cyanate ester (RS-3) or a polyimide (PETI-330) resin containing no MWCNTs. In addition, methods of pre-loading the fabric with the MWCNTs were also investigated. The effects of the MWCNTs on the resin processing properties and on the composite end-use properties were also determined.

Polymeric Materials for Aerospace Power and Propulsion: Overview of Polymer Research at NASA Glenn

Science.gov (United States)

Meador, Michael A.

2007-01-01

Weight, durability and performance are all major concerns for any NASA mission. Use of lightweight materials, such as fiber reinforced polymer matrix composites can lead to significant reductions in vehicle weight and improvements in vehicle performance. Research in the Polymeric Materials Branch at NASA Glenn is focused on improving the durability, properties, processability and performance of polymeric materials by utilizing both conventional polymer science and engineering as well as nanotechnology and bioinspired approaches. This presentation will provide an overview of these efforts and highlight recent progress.

Application of plasma technology for the modification of polymer and textile materials

Directory of Open Access Journals (Sweden)

Radetić Maja M.

2004-01-01

Full Text Available Plasma treatment is based on the physico-chemical changes of the material surface and as an ecologically and economically acceptable process it can be an attractive alternative to conventional modifications. The possibilities of plasma technology application to the modification of polymer and textile materials are discussed. Different specific properties of the material can be achieved by plasma cleaning, etching, functionalization or polymerization. The final effects are strongly influenced by the treatment parameters (treatment time, pressure, power, gas flow, the applied gas and nature of the material. The plasma treatment of polymers is predominantly focused on cleaning and activation of the surfaces to increase adhesion, binding, wettability, dye ability and printability. Current studies deal more with plasma polymerization where an ultra thin film of plasma polymer is deposited on the material surface and, depending on the applied monomer, different specific properties can be obtained (i.e. chemical and thermal resistance, abrasion resistance, antireflexion, water repellence, etc.. Plasma application to textiles is mostly oriented toward wool and synthetic fibres, though some studies also consider cotton, hemp, flax and silk. The main goal of plasma treatment is to impart a more hydrophilic fibre surface and accordingly increase wettability, dye ability, printability and particularly, shrink resistance in the case of wool. Recent studies have favored technical textiles, where plasma polymerization can offer a wide range of opportunities.

SU-E-T-184: Feasibility of Superabsorbent Polymers as a Buildup Material

Energy Technology Data Exchange (ETDEWEB)

Tseng, T; Sheu, R; Lo, Y [Mount Sinai Medical Center, NY, NY (United States)

2014-06-01

Purpose: To investigate the feasibility of superabsorbent polymers as a buildup material for radiation therapy Methods: A standard bolus, a layered damp towel, and a superabsorbent polymer (SAP) phantom were created and scanned to compare the Hounsfield units of each buildup material. A single field plan was developed on Eclipse TPS with AAA dose calculation algorithm to examine dose buildup. Relative film dosimetery (EBT3) was performed to evaluate the surface dose with each buildup material. Each buildup material had an approximate thickness of 0.5 cm and 100 monitor units with 6MV were delivered with solid water placed underneath film to simulate backscatter and more realistic surface dose. Results: The average HU units of the bolus, wet towel, and SAP phantom were 75 (SD=3), -378 (SD=113), -198 (SD=45) respectively. AAA dose calculation demonstrated sufficient dose buildup in all three materials. The relative surfaces doses to film were 23.7% without buildup, 87.5% with 0.5 cm bolus, 92.4% for the SAP phantom, and 87.1% for the damp towel. Conclusion: We demonstrate that superabsorbent polymers can provide sufficient dose buildup. Furthermore, due to the form in which SAPs are traditionally manufactured, this material is less expensive conforms more easily to irregular surfaces than standard sheets of bolus. Also, as a substance which is designed to absorb and retain water efficiently, SAPs are much more comfortable and more consistent than damp towels.

SU-E-T-184: Feasibility of Superabsorbent Polymers as a Buildup Material

International Nuclear Information System (INIS)

Tseng, T; Sheu, R; Lo, Y

2014-01-01

Purpose: To investigate the feasibility of superabsorbent polymers as a buildup material for radiation therapy Methods: A standard bolus, a layered damp towel, and a superabsorbent polymer (SAP) phantom were created and scanned to compare the Hounsfield units of each buildup material. A single field plan was developed on Eclipse TPS with AAA dose calculation algorithm to examine dose buildup. Relative film dosimetery (EBT3) was performed to evaluate the surface dose with each buildup material. Each buildup material had an approximate thickness of 0.5 cm and 100 monitor units with 6MV were delivered with solid water placed underneath film to simulate backscatter and more realistic surface dose. Results: The average HU units of the bolus, wet towel, and SAP phantom were 75 (SD=3), -378 (SD=113), -198 (SD=45) respectively. AAA dose calculation demonstrated sufficient dose buildup in all three materials. The relative surfaces doses to film were 23.7% without buildup, 87.5% with 0.5 cm bolus, 92.4% for the SAP phantom, and 87.1% for the damp towel. Conclusion: We demonstrate that superabsorbent polymers can provide sufficient dose buildup. Furthermore, due to the form in which SAPs are traditionally manufactured, this material is less expensive conforms more easily to irregular surfaces than standard sheets of bolus. Also, as a substance which is designed to absorb and retain water efficiently, SAPs are much more comfortable and more consistent than damp towels

Tetrazole amphiphile inducing growth of conducting polymers hierarchical nanostructures and their electromagnetic absorption properties

Science.gov (United States)

Xie, Aming; Sun, Mengxiao; Zhang, Kun; Xia, Yilu; Wu, Fan

2018-05-01

Conducting polymers (CPs) at nano scales endow materials with special optical, electrical, and magnetic properties. The crucial factor to construct and regulate the micro-structures of CPs is the inducing reagent, particular in its chemical structure, such active sites, self-assembling properties. In this paper, we design and synthesize an amphiphile bearing tetrazole moiety on its skeleton, and use this amphiphile as an inducing reagent to prepare and regulate the micro-structures of a series of CPs including polypyrrole, polyaniline, poly(3,4-ethylenedioxythiophene) and poly(p-phenylenediamine). Because of the unique electric properties of CPs and size effect, we next explored the electromagnetic absorption performances of these CPs nanostructures. A synergetic combination of electric loss and magnetic loss is used to explain the absorption mechanism of these CPs nano-structures.

Structure carbon materials: clusters, nanotubes, ion-implant polymers and diamonds

International Nuclear Information System (INIS)

Lapchuk, N.M.; Odzhaev, V.B.; Poklonskij, N.A.; Sviridov, D.V.

2009-01-01

The paper summarizes the series of research works dealing with the physics of nanostructured carbon materials, which were awarded a Sevchenko Prize in 2008. The paper considers the mechanism of synthesis of 3D carbon nanospecies and their nanomechanics, magnetic properties of ion-implanted diamonds, as well as the regularities of formation of novel forms of amorphous hydrogenated carbon and metal-carbon nanocomposites via ion bombardment of polymers, as well as electronic, magnetic, and structural properties of ion-implanted polymers an their possible applications in micro- and nanoelectronics. (authors)

Method of Making an Electroactive Sensing/Actuating Material for Carbon Nanotube Polymer Composite

Science.gov (United States)

Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Draughon, Gregory K. (Inventor)

2009-01-01

An electroactive sensing or actuating material comprises a composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation of the composite when such composite is affected by an external stimulus. In another embodiment, the composite comprises a, third component of micro -sized to nano-sized particles of an electroactive ceramic that is also incorporated in the polymer matrix. The method for making the three-phase composite comprises either incorporating the carbon nanotubes in the polymer matrix before incorporation of the particles of ceramic or mixing the carbon nanotubes and particles of ceramic together in a solution before incorporation in the polymer matrix.

Self-positioning of polymer membranes driven by thermomechanically induced plastic deformation

DEFF Research Database (Denmark)

Häfliger, Daniel; Hansen, Ole; Boisen, Anja

2006-01-01

Stress in polymeric resins is tailored by a thermomechanical process. It allows for controlled self-positioning of membranes in microdevices (see Figure). The process makes specific use of plastic deformation that results from the low viscosity of the polymer. This demonstrates that polymers offer...... new approaches to microfabrication that cannot be realized for common semiconductor materials without severe difficulties....

United States of America [Status and technology of polymer-containing fibrous materials in the Western Hemisphere

International Nuclear Information System (INIS)

Rotariu, G.J.; Mott, W.E.

1968-01-01

A research and development program on the radiation curing of wood impregnated with a monomer was initiated in the United States in 1961 by the U.S. Atomic Energy Commission at West Virginia University; this program has continued until today. The USAEC has also sponsored three studies covering different geographical areas of the country, in an attempt to determine the potential of wood-polymer materials. Another effort led to the design of a 200 pound per hour pilot plant for the manufacture of wood-methyl methacrylate materials and projected costs for a 300 pound per hour production plant. And the most recent AEC study involved the evaluation of over 8000 pounds of wood-polymer materials by 68 manufacturers of wood products; the wood-polymer materials utilizing 41 species of wood were produced for the AEC by Lockheed-Georgia Company, Dawsonville, Georgia. In 1965, studies on the thermal-catalytic production of wood polymers were begun at the College of Forestry, Syracuse University, Syracuse, New York

United States of America [Status and technology of polymer-containing fibrous materials in the Western Hemisphere

Energy Technology Data Exchange (ETDEWEB)

Rotariu, G. J.; Mott, W. E. [United States Atomic Energy Commission, Washington, DC 2054 (United States)

1968-10-15

A research and development program on the radiation curing of wood impregnated with a monomer was initiated in the United States in 1961 by the U.S. Atomic Energy Commission at West Virginia University; this program has continued until today. The USAEC has also sponsored three studies covering different geographical areas of the country, in an attempt to determine the potential of wood-polymer materials. Another effort led to the design of a 200 pound per hour pilot plant for the manufacture of wood-methyl methacrylate materials and projected costs for a 300 pound per hour production plant. And the most recent AEC study involved the evaluation of over 8000 pounds of wood-polymer materials by 68 manufacturers of wood products; the wood-polymer materials utilizing 41 species of wood were produced for the AEC by Lockheed-Georgia Company, Dawsonville, Georgia. In 1965, studies on the thermal-catalytic production of wood polymers were begun at the College of Forestry, Syracuse University, Syracuse, New York.

Polymerization Simulator for Introductory Polymer and Material Science Courses

Science.gov (United States)

Chirdon, William M.

2010-01-01

This work describes how molecular simulation of polymerization reactions can be used to enrich introductory polymer or material science courses to give students a deeper understanding of free-radical chain and stepwise growth polymerization reactions. These simulations have proven to be effective media for instruction that do not require material…

Space environment effects on polymers in low earth orbit

International Nuclear Information System (INIS)

Grossman, E.; Gouzman, I.

2003-01-01

Polymers are widely used in space vehicles and systems as structural materials, thermal blankets, thermal control coatings, conformal coatings, adhesives, lubricants, etc. The low earth orbit (LEO) space environment includes hazards such as atomic oxygen, UV radiation, ionizing radiation (electrons, protons), high vacuum, plasma, micrometeoroids and debris, as well as severe temperature cycles. Exposure of polymers and composites to the space environment may result in different detrimental effects via modification of their chemical, electrical, thermal, optical and mechanical properties as well as surface erosion. The high vacuum induces material outgassing (e.g. low-molecular weight residues, plasticizers and additives) and consequent contamination of nearby surfaces. The present work reviews the LEO space environment constituents and their interactions with polymers. Examples of degradation of materials exposed in ground simulation facilities are presented. The issues discussed include the erosion mechanisms of polymers, formation of contaminants and their interaction with the space environment, and protection of materials from the harsh space environment

Making Molecular Balloons in Laser-Induced Explosive Boiling of Polymer Solutions

International Nuclear Information System (INIS)

Leveugle, Elodie; Sellinger, Aaron; Fitz-Gerald, James M.; Zhigilei, Leonid V.

2007-01-01

The effect of the dynamic molecular rearrangements leading to compositional segregation is revealed in coarse-grained molecular dynamics simulations of short pulse laser interaction with a polymer solution in a volatile matrix. An internal release of matrix vapor at the onset of the explosive boiling of the overheated liquid is capable of pushing polymer molecules to the outskirts of a transient bubble, forming a polymer-rich surface layer enclosing the volatile matrix material. The results explain unexpected 'deflated balloon' structures observed in films deposited by the matrix-assisted pulsed laser evaporation technique

Advances in supramolecular polymer chemistry : well-defined terpyridine-functionalized materials

NARCIS (Netherlands)

Ott, C.

2008-01-01

Controlled/"living" polymerization techniques have attracted enormous attention in the field of polymer science since they have opened an avenue to the preparation of well-defined materials with precisely designed molecular architectures like random, block, graft and comb copolymers. These

Evaluation of extractables in processed and unprocessed polymer materials used for pharmaceutical applications.

Science.gov (United States)

Stults, Cheryl L M; Ansell, Jennifer M; Shaw, Arthur J; Nagao, Lee M

2015-02-01

Polymeric materials are often used in pharmaceutical packaging, delivery systems, and manufacturing components. There is continued concern that chemical entities from polymeric components may leach into various dosage forms, particularly those that are comprised of liquids such as parenterals, injectables, ophthalmics, and inhalation products. In some cases, polymeric components are subjected to routine extractables testing as a control measure. To reduce the risk of discovering leachables during stability studies late in the development process, or components that may fail extractables release criteria, it is proposed that extractables testing on polymer resins may be useful as a screening tool. Two studies have been performed to evaluate whether the extractables profile generated from a polymer resin is representative of the extractables profile of components made from that same resin. The ELSIE Consortium pilot program examined polyvinyl chloride and polyethylene, and another study evaluated polypropylene and a copolymer of polycarbonate and acrylonitrile butadiene styrene. The test materials were comprised of polymer resin and processed resin or molded components. Volatile, semi-volatile, and nonvolatile chemical profiles were evaluated after headspace sampling and extraction with solvents of varying polarity and pH. The findings from these studies indicate that there may or may not be differences between extractables profiles obtained from resins and processed forms of the resin depending on the type of material, the compounds of interest, and extraction conditions used. Extractables testing of polymer resins is useful for material screening and in certain situations may replace routine component testing.

Polymer electronics

CERN Document Server

Hsin-Fei, Meng

2013-01-01

Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

Numerical modelling of porous cement-based materials by superabsorbent polymers

DEFF Research Database (Denmark)

Viejo, Ismael; Esteves, Luis Pedro; Laspalas, Manuel

2016-01-01

The development of new cementitious materials raises new challenges with regard to structural design. One of the potential applications of superabsorbent polymers (SAP) is to deliver well-defined porosity to cement systems. This is particularly interesting for the development of porous cement...

Desolvation Induced Origami of Photocurable Polymers by Digit Light Processing.

Science.gov (United States)

Zhao, Zeang; Wu, Jiangtao; Mu, Xiaoming; Chen, Haosen; Qi, H Jerry; Fang, Daining

2017-07-01

Self-folding origami is of great interest in current research on functional materials and structures, but there is still a challenge to develop a simple method to create freestanding, reversible, and complex origami structures. This communication provides a feasible solution to this challenge by developing a method based on the digit light processing technique and desolvation-induced self-folding. In this new method, flat polymer sheets can be cured by a light field from a commercial projector with varying intensity, and the self-folding process is triggered by desolvation in water. Folded origami structures can be recovered once immersed in the swelling medium. The self-folding process is investigated both experimentally and theoretically. Diverse 3D origami shapes are demonstrated. This method can be used for responsive actuators and the fabrication of 3D electronic devices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pseudo-stationary separation materials for highly parallel separations.

Energy Technology Data Exchange (ETDEWEB)

Singh, Anup K.; Palmer, Christopher (University of Montana, Missoula, MT)

2005-05-01

Goal of this study was to develop and characterize novel polymeric materials as pseudostationary phases in electrokinetic chromatography. Fundamental studies have characterized the chromatographic selectivity of the materials as a function of chemical structure and molecular conformation. The selectivities of the polymers has been studied extensively, resulting in a large body of fundamental knowledge regarding the performance and selectivity of polymeric pseudostationary phases. Two polymers have also been used for amino acid and peptide separations, and with laser induced fluorescence detection. The polymers performed well for the separation of derivatized amino acids, and provided some significant differences in selectivity relative to a commonly used micellar pseudostationary phase. The polymers did not perform well for peptide separations. The polymers were compatible with laser induced fluorescence detection, indicating that they should also be compatible with chip-based separations.

Ions-induced nanostructuration: effect of specific ionic adsorption on hydrophobic polymer surfaces.

Science.gov (United States)

Siretanu, Igor; Chapel, Jean-Paul; Bastos-González, Delfi; Drummond, Carlos

2013-06-06

The effect of surface charges on the ionic distribution in close proximity to an interface has been extensively studied. On the contrary, the influence of ions (from dissolved salts) on deformable interfaces has been barely investigated. Ions can adsorb from aqueous solutions on hydrophobic surfaces, generating forces that can induce long-lasting deformation of glassy polymer films, a process called ion-induced polymer nanostructuration, IPN. We have found that this process is ion-specific; larger surface modifications are observed in the presence of water ions and hydrophobic and amphiphilic ions. Surface structuration is also observed in the presence of certain salts of lithium. We have used streaming potential and atomic force microscopy to study the effect of dissolved ions on the surface properties of polystyrene films, finding a good correlation between ionic adsorption and IPN. Our results also suggest that the presence of strongly hydrated lithium promotes the interaction of anions with polystyrene surfaces and more generally with hydrophobic polymer surfaces, triggering then the IPN process.

New frontiers in Combinatorial and High-Throughput Materials and Polymer Research: 3rd DPI workshop on automated synthesis and high-throughput experimentation in Polymer and Materials Research at the Eindhoven University of Technology

NARCIS (Netherlands)

Adams, N.; Schubert, U.S.

2005-01-01

The Third International Workshop on Combinatorial and High-Throughput Materials and Polymer Research, sponsored and organized by the Dutch Polymer Institute (DPI), took place at the Eindhoven University of Technol., The Netherlands, on May 26 - 27, 2004. The workshop's purpose is two-fold: its

Gas-Transport-Property Performance of Hybrid Carbon Molecular Sieve−Polymer Materials

KAUST Repository

Das, Mita

2010-10-06

High-performance hybrid materials using carbon molecular sieve materials and 6FDA-6FpDA were produced. A detailed analysis of the effects of casting processes and the annealing temperature is reported. Two existing major obstacles, sieve agglomeration and residual stress, were addressed in this work, and subsequently a new membrane formation technique was developed to produce high-performing membranes. The successfully improved interfacial region of the hybrid membranes allows the sieves to increase the selectivity of the membranes above the neat polymer properties. Furthermore, an additional performance enhancement was seen with increased sieve loading in the hybrid membranes, leading to an actual performance above the upper bound for pure polymer membranes. The membranes were also tested under a mixed-gas environment, which further demonstrated promising results. © 2010 American Chemical Society.

Fracture mechanics of polymer mortar made with recycled raw materials

OpenAIRE

Jurumenha,Marco Antonio Godoy; Reis,João Marciano Laredo dos

2010-01-01

The aim of this work is to show that industrial residues could be used in construction applications so that production costs as well as environmental protection can be improved. The fracture properties of polymer mortar manufactured with recycled materials are investigated to evaluate the materials behaviour to crack propagation. The residues used in this work were spent sand from foundry industry as aggregate, unsaturated polyester resin from polyethylene terephthalate (PET) as matrix and po...

Synthesis by plasma of polymer-metal materials

International Nuclear Information System (INIS)

Fernandez R, G.

2004-01-01

The objective of this work is the design of an experimental set-up to synthesize polymer- metal composites by plasma with versatility in the conditions of synthesis. The main components are a vacuum system capable to reach up to 10 -2 mbar and valves and accessories to control the pressure in the system. In order to generate the electrical discharges and the plasma, an electrical circuit with an inductive connection at 13.56 MHz of frequency was constructed. The electric field partially ionizes the reactor atmosphere where the polymer-metal composites were synthesized. The reactor has two metallic electrodes, one in front of the other, where the particles electrically charged collide against the electrodes producing ablation on them. The polymer-metal composites were synthesized by means of an inductive connection at 13.56 MHz. Aniline, 3-chlorine-ethylene and electrodes of silver (Ag) and copper (Cu) were used in a cylindrical reactor coupled with an external coil to generate glow discharges. The average pressures were 6.15 X 10 -1 and 5.2 X 10 -1 mbar for the synthesis of Poly aniline (P An) and Poly chloroethylene (PE-CI), respectively. The synthesis was performed during 60 and 180 minutes for P An and PE-CI, respectively. The polymers were formed, as films, with an average thickness of 6.42 μm for P An and, in the case of PE-CI, with an approximately growing rate of 14 ηm/W. The power in the syntheses was 30, 50, 70 and 90 W for P An and 50, 100, 120, 140 170, and 200 W for PE-CI. The characterization of the polymer-metal composites was done by energy dispersive spectroscopy to study the composition and the relation of the elements involved in the synthesis. The morphology of the films was studied by means of scanning electron microscopy. The infrared analysis (IR) was done to study the chemicals bonds and the structure of these polymers. Another important study in these materials was the behavior of the electrical conductivity (σ), which was complemented

The potential of organic polymer-based hydrogen storage materials.

Science.gov (United States)

Budd, Peter M; Butler, Anna; Selbie, James; Mahmood, Khalid; McKeown, Neil B; Ghanem, Bader; Msayib, Kadhum; Book, David; Walton, Allan

2007-04-21

The challenge of storing hydrogen at high volumetric and gravimetric density for automotive applications has prompted investigations into the potential of cryo-adsorption on the internal surface area of microporous organic polymers. A range of Polymers of Intrinsic Microporosity (PIMs) has been studied, the best PIM to date (a network-PIM incorporating a triptycene subunit) taking up 2.7% H(2) by mass at 10 bar/77 K. HyperCrosslinked Polymers (HCPs) also show promising performance as H(2) storage materials, particularly at pressures >10 bar. The N(2) and H(2) adsorption behaviour at 77 K of six PIMs and a HCP are compared. Surface areas based on Langmuir plots of H(2) adsorption at high pressure are shown to provide a useful guide to hydrogen capacity, but Langmuir plots based on low pressure data underestimate the potential H(2) uptake. The micropore distribution influences the form of the H(2) isotherm, a higher concentration of ultramicropores (pore size <0.7 nm) being associated with enhanced low pressure adsorption.

Incorporation of New Benzofulvene Derivatives Into Polymers to Give New NLO Materials

Science.gov (United States)

Bowens, Andrea D.; Bu, Xiu; Mintz, Eric A.; Zhang, Yue

1996-01-01

The need for fast electro-optic switches and modulators for optical communication, and laser frequency conversion has created a demand for new second-order non-linear optical materials. One approach to produce such materials is to align chromophores with large molecular hyperpolarizabilities in polymers. Recently fulvenes and benzofulvenes which contain electron donating groups have been shown to exhibit large second-order non-linear optical properties. The resonance structures shown below suggest that intramolecular charge transfer (ICT) should be favorable in omega - (hydroxyphenyl)benzofulvenes and even more favorable in omega-omega - (phenoxy)benzofulvenes because of the enhanced donor properties of the O group. This ICT should lead to enormously enhanced second-order hyperpolarizability. We have prepared all three new omega - (hydroxyphenyl)benzofulvenes by the condensation of indene with the appropriate hydroxyaryl aldehyde in MeOH or MeOH/H2O under base catalysis. In a similar fashion we have prepared substituted benzofulvenes with multipal donor groups. Preliminary studies show that some of our benzofulvene derivatives exhibit second order harmonic generation (SHG). Measurements were carried out by preparing host-guest polymers. The results of our work on benzofulvene derivatives in host-guest polymers when covalently bonded in the polymer will be described.

The influence of the PDMS technique in the study of the induced modifications of polymers used in nuclear environment

International Nuclear Information System (INIS)

Nsouli, B.

1995-01-01

The PDMS technique (Particle Induced Desorption Mass Spectrometry) combined with a TOF detection (Time of Flight) is the main tool used in this study of polymer degradation in nuclear environment. Ar 3+ ions with a 9 MeV energy have been used to induce the secondary ion emission, and the study was devoted to two stresses typical of this type of environment. The first part of the work concerned with the structural modifications induced by gamma irradiation on ion exchange resin, used for nuclear effluents reprocessing, namely the poly(4-vinylpyridine), or P-4PV. For such a material, the negative fragment emission is particularly sensitive to structural modifications. Difficult physical measurements in such an insoluble and infusible material (IR, UV - Vis, EPR, TGA, dielectric measurements) became consistent after the degradation mechanisms were elucidated. These effects, interpreted in terms of scissions and recombinations, enabled us to explicit different modes of energy deposition, and shed light on some discrepancies between SIMS and PDMS. The second part of the study is devoted to the thermal ageing of an elastomer, used in fabrication of valve gaskets submitted to high temperatures. First of all, we studied the constituents of the polymeric material, i. e. copolymer, homo polymers, and also additives. This last component proved useful to analyze, as a superficial lubricant layer can mask the conformational rearrangements which seem to occur after few hours of thermal treatment (PE blocks are prevailing at the surface). Here too, the PDMS information is important to account for static SIMS and ESCA results, as its probed layer thickness lies in-between. (author)

Application of capacitively coupled rf discharge plasma for sterilization of polymer materials used in ophthalmology

International Nuclear Information System (INIS)

Abdullin, I.Sh.; Avetisov, S.E.; Lipatov, D.V.; Rybakova, E.G.; Bragin, V.E.; Bykanov, A.N.; Kamarentsev, E.N.

1996-01-01

The sterilization effect of capacitively coupled rf discharge plasma treatment of contact lenses was investigated. There were used two types of polymer: highly hydrophilic polymer with water content 76% (Navelen-76) and poly-methylmethacrylate (PMMA). There was demonstrated the possibility of effective sterilization by RF discharge plasma of a set of polymer materials used in ophthalmology. The best results were obtained for hard contact lenses. There was perfect sterilization in this case. There were not perfect sterilization in some cases of soft contact lenses treatment. It may be caused by porous structure of the external layers of this material and limited thickness of the sterilization layer. (author)

Fabrication and characterisation of a novel biomimetic anisotropic ceramic/polymer-infiltrated composite material.

Science.gov (United States)

Al-Jawoosh, Sara; Ireland, Anthony; Su, Bo

2018-04-10

To fabricate and characterise a novel biomimetic composite material consisting of aligned porous ceramic preforms infiltrated with polymer. Freeze-casting was used to fabricate and control the microstructure and porosity of ceramic preforms, which were subsequently infiltrated with 40-50% by volume UDMA-TEGDMA polymer. The composite materials were then subjected to characterisation, namely density, compression, three-point bend, hardness and fracture toughness testing. Samples were also subjected to scanning electron microscopy and computerised tomography (Micro-CT). Three-dimensional aligned honeycomb-like ceramic structures were produced and full interpenetration of the polymer phase was observed using micro-CT. Depending on the volume fraction of the ceramic preform, the density of the final composite ranged from 2.92 to 3.36g/cm 3 , compressive strength ranged from 206.26 to 253.97MPa, flexural strength from 97.73 to 145.65MPa, hardness ranged from 1.46 to 1.62GPa, and fracture toughness from 3.91 to 4.86MPam 1/2 . Freeze-casting provides a novel method to engineer composite materials with a unique aligned honeycomb-like interpenetrating structure, consisting of two continuous phases, inorganic and organic. There was a correlation between the ceramic fraction and the subsequent, density, strength, hardness and fracture toughness of the composite material. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Fabrication of a PANI/CPs composite material: a feasible method to enhance the photocatalytic activity of coordination polymers.

Science.gov (United States)

Xu, Xin-Xin; Cui, Zhong-Ping; Qi, Ji; Liu, Xiao-Xia

2013-03-21

To improve the photocatalytic activity of a coordination polymer in the visible light region, polyaniline (PANI) was loaded onto its surface through a facile in situ chemical oxidation polymerization process. The resulting PANI loaded coordination polymer composite materials with excellent stability exhibit significantly higher photocatalytic activities than the pure coordination polymer photocatalyst on the degradation of methyl orange (MO) under visible light irradiation. This enhancement can be ascribed to the introduction of PANI on the surface of the coordination polymer, which leads to efficient separation of photogenerated electron-hole pairs as well as a significant expansion of the photoresponse region. Finally, we discussed the influence of acidity on the morphology and photocatalytic activity of the composite material. An optimal condition to obtain the PANI loaded coordination polymer composite material with excellent photocatalytic activity has been obtained.

A life cycle framework to support materials selection for Ecodesign: A case study on biodegradable polymers

International Nuclear Information System (INIS)

Ribeiro, I.; Peças, P.; Henriques, E.

2013-01-01

Highlights: • Life cycle framework to support material selection in Ecodesign. • Early design stage estimates and sensitivity analyses based on process-based models. • Sensitivity analysis to product geometry, industrial context and EoL scenarios. • Cost and environmental performance comparison – BDP vs. fossil based polymers. • Best alternatives mapping integrating cost and environmental performances. - Abstract: Nowadays society compels designers to develop more sustainable products. Ecodesign directs product design towards the goal of reducing environmental impacts. Within Ecodesign, materials selection plays a major role on product cost and environmental performance throughout its life cycle. This paper proposes a comprehensive life cycle framework to support Ecodesign in material selection. Dealing with new materials and technologies in early design stages, process-based models are used to represent the whole life cycle and supply integrated data to assess material alternatives, considering cost and environmental dimensions. An integrated analysis is then proposed to support decision making by mapping the best alternative materials according to the importance given to upstream and downstream life phases and to the environmental impacts. The proposed framework is applied to compare the life cycle performance of injection moulded samples made of four commercial biodegradable polymers with different contents of Thermo Plasticized Starch and PolyLactic Acid and a common fossil based polymer, Polypropylene. Instead of labelling materials just as “green”, the need to fully capture all impacts in the whole life cycle was shown. The fossil based polymer is the best economic alternative, but polymers with higher content of Thermo Plasticized Starch have a better environmental performance. However, parts geometry and EoL scenarios play a major role on the life cycle performance of candidate materials. The selection decision is then supported by mapping

Relaxation model of radiation-induced conductivity in polymers

Science.gov (United States)

Zhutayeva, Yu. R.; Khatipov, S. A.

1999-05-01

The paper suggests a relaxation model of radiation-induced conductivity (RIC) in polymers. According to the model, the transfer of charges generated in the polymer volume by ionizing radiation takes place with the participation of molecular relaxation processes. The mechanism of electron transport consists in the transfer of the charge directly between traps when they draw close to one another due to the rotation of macromolecule segments. The numerical solutions of the corresponding kinetic equations for different distribution functions Q( τ) of the times of molecular relaxation and for different functions of the probability P( τ, τ') of charge transfer in the `overlapping' regions of the diffusion spheres of the segments are analyzed. The relaxation model provides an explanation of the non-Arrhenius behavior of the RIC temperature dependence, the power dependence of RIC on the dose rate with a power index in the interval 0.5-1.0, the appearance of maxima in the curves of the RIC temporal dependence and their irreversible character in the region of large dose rates (more than 1 Gy/s). The model can be used for interpreting polymer RIC in conditions of kinetic mobility of macromolecules.

Failure of structural elements made of polymer supported composite materials during the multiyear natural aging

Science.gov (United States)

Blinkov, Pavel; Ogorodov, Leonid; Grabovyy, Peter

2018-03-01

Modern high-rise construction introduces a number of limitations and tasks. In addition to durability, comfort and profitability, projects should take into account energy efficiency and environmental problems. Polymer building materials are used as substitutes for materials such as brick, concrete, metal, wood and glass, and in addition to traditional materials. Plastic materials are light, can be formed into complex shapes, durable and low, and also possess a wide range of properties. Plastic materials are available in various forms, colors and textures and require minimal or no color. They are resistant to heat transfer and diffusion of moisture and do not suffer from metal corrosion or microbial attack. Polymeric materials, including thermoplastics, thermoset materials and wood-polymer composites, have many structural and non-structural applications in the construction industry. They provide unique and innovative solutions at a low cost, and their use is likely to grow in the future. A number of polymer composite materials form complex material compositions, which are applied in the construction in order to analyze the processes of damage accumulation under the conditions of complex nonstationary loading modes, and to determine the life of structural elements considering the material aging. This paper present the results of tests on short-term compression loading with a deformation rate of v = 2 mm/min using composite samples of various shapes and sizes.

Polymer-Graphene Nanocomposite Materials for Electrochemical Biosensing.

Science.gov (United States)

Sobolewski, Peter; Piwowarczyk, Magdalena; Fray, Mirosława El

2016-07-01

Biosensing is an important and rapidly developing field, with numerous potential applications in health care, food processing, and environmental control. Polymer-graphene nanocomposites aim to leverage the unique, attractive properties of graphene by combining them with those of a polymer matrix. Molecular imprinted polymers, in particular, offer the promise of artificial biorecognition elements. A variety of polymers, including intrinsically conducting polymers (polyaniline, polypyrrole), bio-based polymers (chitosan, polycatechols), and polycationic polymers (poly(diallyldimethylammonium chloride), polyethyleneimine), have been utilized as matrices for graphene-based nanofillers, yielding sensitive biosensors for various biomolecules, such as proteins, nucleic acids, and small molecules. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modeling and analysis rheology of polymers for application in technologies “self-crimping” and its adaptation to the practices of Polymer Materials Engineering

Directory of Open Access Journals (Sweden)

N. Montanes

2017-01-01

Full Text Available Polymers are manufactured in molted state, so the rheological properties are mandatory in order to analyse and evaluate its processability. The prediction of the viscoelastic response of a material and the simulation of the behavior of the same when it is processed is achieved with the application of the rheological models. In  the  preparation  by  extrusion  of  bicomponent  polymer fibers  with  self-crimping  effect  it  is  essential that  the  two  components  have  the  same  viscosity  at  the  nozzle  outlet.  In  order  to  obtain  such  viscosity each  component must  be  extruded  at a  different  temperature maintaining  all  other  processing  conditions unchanged. Using Cross-WLF rheological modelization is it feasible to determine the temperatures for two polymeric materials in order to obtain the same melt viscosity. In the current work a practical session has been proposed for students of Materials Engineering. Using a capillary rheometer, the students should be able to determine the rheological behavior of two thermoplastic polymers. After adjusting the behavior of the polymers to Cross-WLF model and using the proposed model the students should be able to determine the temperatures in which both polymers have the same viscosity.

Multicomponent semiconducting polymer systems with low crystallization-induced percolation threshold

DEFF Research Database (Denmark)

Goffri, S.; Müller, C.; Stingelin-Stutzmann, N.

2006-01-01

of the two components, during which the semiconductor is predominantly expelled to the surfaces of cast films, we can obtain vertically stratified structures in a one-step process. Incorporating these as active layers in polymer field-effect transistors, we find that the concentration of the semiconductor......–crystalline/semiconducting–insulating multicomponent systems offer expanded flexibility for realizing high-performance semiconducting architectures at drastically reduced materials cost with improved mechanical properties and environmental stability, without the need to design all performance requirements into the active semiconducting polymer...

Brush-Like Polymers: New Design Platforms for Soft, Dry Materials with Unique Property Relations

Science.gov (United States)

Daniel, William Francis McKemie, Jr.

Elastomers represent a unique class of engineering materials due to their light weight, low cost, and desirable combination of softness (105 -107 Pa) and large extensibilities (up to 1000%). Despite these advantages, there exist applications that require many times softer modulus, greater extensibility, and stronger strain hardening for the purpose of mimicking the mechanical properties of systems such as biological tissues. Until recently, only liquid-filled gels were suitable materials for such applications, including soft robotics and implants. A considerable amount of work has been done to create gels with superior properties, but despite unique strengths they also suffer from unique weaknesses. This class of material displays fundamental limitations in the form of heterogeneous structures, solvent loss and phase transitions at extreme temperatures, and loss of liquid fraction upon high deformations. In gels the solvent fraction also introduces a large solvent/polymer interaction parameter which must be carefully considered when designing the final mechanical properties. These energetic considerations further exaggerate the capacity for inconstant mechanical properties caused by fluctuations of the solvent fraction. In order to overcome these weaknesses, a new platform for single component materials with low modulus (Standard networks have one major control factor outside of chemistry, the network stand length. Brush-like architectures are created from long strands with regularly grafted side chains creating three characteristic length scales which may be independently manipulated. In collaboration with M. Rubinstein, we have utilized bottlebrush polymer architectures (a densely grafted brush-like polymer) to experimentally verify theoretical predictions of disentangled bottlebrush melts. By attaching well-defined side chains onto long polymer backbones, individual polymer strands are separated in space (similar to dilution with solvent) accompanied by a

Flow induced/ refined solution crystallization of a semiconducting polymer

Science.gov (United States)

Nguyen, Ngoc A.

Organic photovoltaics, a new generation of solar cells, has gained scientific and economic interests due to the ability of solution-processing and potentially low-cost power production. Though, the low power conversion efficiency of organic/ plastic solar cells is one of the most pertinent challenges that has appealed to research communities from many different fields including materials science and engineering, electrical engineering, chemical engineering, physics and chemistry. This thesis focuses on investigating and controlling the morphology of a semi-conducting, semi-crystalline polymer formed under shear-flow. Molecular structures and processing techniques are critical factors that significantly affect the morphology formation in the plastic solar cells, thus influencing device performance. In this study, flow-induced solution crystallization of poly (3-hexylthiophene) (P3HT) in a poor solvent, 2-ethylnapthalene (2-EN) was utilized to make a paint-like, structural liquid. The polymer crystals observed in this structured paint are micrometers long, nanometers in cross section and have a structure similar to that formed under quiescent conditions. There is pi-pi stacking order along the fibril axis, while polymer chain folding occurs along the fibril width and the order of the side-chain stacking is along fibril height. It was revealed that shear-flow not only induces P3HT crystallization from solution, but also refines and perfects the P3HT crystals. Thus, a general strategy to refine the semiconducting polymer crystals from solution under shear-flow has been developed and employed by simply tuning the processing (shearing) conditions with respect to the dissolution temperature of P3HT in 2-EN. The experimental results demonstrated that shear removes defects and allows more perfect crystals to be formed. There is no glass transition temperature observed in the crystals formed using the flow-induced crystallization indicating a significantly different

Optical properties of graphene-based materials in transparent polymer matrices

Energy Technology Data Exchange (ETDEWEB)

Bayrak, Osman; Demirci, Emrah, E-mail: E.Demirci@lboro.ac.uk; Silberschmidt, Vadim V. [Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough, LE11 3TU (United Kingdom); Ionita, Mariana [Advanced Polymer Materials Group, University Politehnica of Bucharest, 132 Calea Grivitei, 010737 Bucharest (Romania)

2016-08-22

Different aspects of graphene-based materials (GBMs) and GBM-nanocomposites have been investigated due to their intriguing features; one of these features is their transparency. Transparency of GBMs has been of an interest to scientists and engineers mainly with regard to electronic devices. In this study, optical transmittance of structural, purpose-made nanocomposites reinforced with GBMs was analyzed to lay a foundation for optical microstructural characterization of nanocomposites in future studies. Two main types of GBM reinforcements were studied, graphene oxide (GO) and graphite nanoplates (GNPs). The nanocomposites investigated are GO/poly(vinyl alcohol), GO/sodium alginate, and GNP/epoxy with different volume fractions of GBMs. Together with UV-visible spectrophotometry, image-processing-assisted micro and macro photography were used to assess the transparency of GBMs embedded in the matrices. The micro and macro photography methods developed were proven to be an alternative way of measuring light transmittance of semi-transparent materials. It was found that there existed a linear relationship between light absorbance and a volume fraction of GBMs embedded in the same type of polymer matrices, provided that the nanocomposites of interest had the same thicknesses. This suggests that the GBM dispersion characteristics in the same type of polymer are similar and any possible change in crystal structure of polymer due to different volumetric contents of GBM does not have an effect on light transmittance of the matrices. The study also showed that the same types of GBMs could display different optical properties in different matrix materials. The results of this study will help to develop practical microstructural characterization techniques for GBM-based nanocomposites.

Improving the thermal dimensional stability of flexible polymer composite backing materials for ultrasound transducers

NARCIS (Netherlands)

State, M.; Brands, P.J.; Vosse, van de F.N.

2010-01-01

Novel ultrasound backing materials based on polymer composites with improved dimensional stability and low coefficient of thermal expansion are being developed and analyzed. For this purpose a filled epoxy resin (Stycast1265), a commonly used backing material, was considered reference material and

Occurrence, degradation, and effect of polymer-based materials in the environment.

Science.gov (United States)

Lambert, Scott; Sinclair, Chris; Boxall, Alistair

2014-01-01

There is now a plethora of polymer-based materials (PBMs) on the market, because of the increasing demand for cheaper consumable goods, and light-weight industrial materials. Each PBM constitutes a mixture of their representative polymer/sand their various chemical additives. The major polymer types are polyethylene, polypropylene,and polyvinyl chloride, with natural rubber and biodegradable polymers becoming increasingly more important. The most important additives are those that are biologically active, because to be effective such chemicals often have properties that make them resistant to photo-degradation and biodegradation. During their lifecycle,PBMs can be released into the environment form a variety of sources. The principal introduction routes being general littering, dumping of unwanted waste materials,migration from landfills and emission during refuse collection. Once in the environment,PBMs are primarily broken down by photo-degradation processes, but due to the complex chemical makeup of PBMs, receiving environments are potentially exposed to a mixture of macro-, meso-, and micro-size polymer fragments, leached additives, and subsequent degradation products. In environments where sunlight is absent (i.e., soils and the deep sea) degradation for most PBMs is minimal .The majority of literature to date that has addressed the environmental contamination or disposition of PBMs has focused on the marine environment. This is because the oceans are identified as the major sink for macro PBMs, where they are known to present a hazard to wildlife via entanglement and ingestion. The published literature has established the occurrence of microplastics in marine environment and beach sediments, but is inadequate as regards contamination of soils and freshwater sediments. The uptake of microplastics for a limited range of aquatic organisms has also been established, but there is a lack of information regarding soil organisms, and the long-term effects of

Femtosecond Laser Irradiation of Plasmonic Nanoparticles in Polymer Matrix: Implications for Photothermal and Photochemical Material Alteration

Directory of Open Access Journals (Sweden)

Anton A. Smirnov

2014-11-01

Full Text Available We analyze the opportunities provided by the plasmonic nanoparticles inserted into the bulk of a transparent medium to modify the material by laser light irradiation. This study is provoked by the advent of photo-induced nano-composites consisting of a typical polymer matrix and metal nanoparticles located in the light-irradiated domains of the initially homogeneous material. The subsequent irradiation of these domains by femtosecond laser pulses promotes a further alteration of the material properties. We separately consider two different mechanisms of material alteration. First, we analyze a photochemical reaction initiated by the two-photon absorption of light near the plasmonic nanoparticle within the matrix. We show that the spatial distribution of the products of such a reaction changes the symmetry of the material, resulting in the appearance of anisotropy in the initially isotropic material or even in the loss of the center of symmetry. Second, we analyze the efficiency of a thermally-activated chemical reaction at the surface of a plasmonic particle and the distribution of the product of such a reaction just near the metal nanoparticle irradiated by an ultrashort laser pulse.

Computational micromechanics analysis of electron hopping and interfacial damage induced piezoresistive response in carbon nanotube-polymer nanocomposites

International Nuclear Information System (INIS)

Chaurasia, A K; Seidel, G D; Ren, X

2014-01-01

Carbon nanotube (CNT)-polymer nanocomposites have been observed to exhibit an effective macroscale piezoresistive response, i.e., change in macroscale resistivity when subjected to applied deformation. The macroscale piezoresistive response of CNT-polymer nanocomposites leads to deformation/strain sensing capabilities. It is believed that the nanoscale phenomenon of electron hopping is the major driving force behind the observed macroscale piezoresistivity of such nanocomposites. Additionally, CNT-polymer nanocomposites provide damage sensing capabilities because of local changes in electron hopping pathways at the nanoscale because of initiation/evolution of damage. The primary focus of the current work is to explore the effect of interfacial separation and damage at the nanoscale CNT-polymer interface on the effective macroscale piezoresistive response. Interfacial separation and damage are allowed to evolve at the CNT-polymer interface through coupled electromechanical cohesive zones, within a finite element based computational micromechanics framework, resulting in electron hopping based current density across the separated CNT-polymer interface. The macroscale effective material properties and gauge factors are evaluated using micromechanics techniques based on electrostatic energy equivalence. The impact of the electron hopping mechanism, nanoscale interface separation and damage evolution on the effective nanocomposite electrostatic and piezoresistive response is studied in comparison with the perfectly bonded interface. The effective electrostatic/piezoresistive response for the perfectly bonded interface is obtained based on a computational micromechanics model developed in the authors’ earlier work. It is observed that the macroscale effective gauge factors are highly sensitive to strain induced formation/disruption of electron hopping pathways, interface separation and the initiation/evolution of interfacial damage. (paper)

Poly(vinylidene fluoride) modification induced by gamma irradiation for application as ionic polymer-metal composite

International Nuclear Information System (INIS)

Ferreira, Henrique Perez

2011-01-01

Gamma-radiation-induced grafting of styrene into poly(vinylidene fluoride) (PVDF) films with 0.125 mm thickness at doses from 1 to 100 kGy in the presence of a styrene/N,N- dimethylformamide (DMF) solution (1:1, v/v) and styrene/toluene (1:1, v/v) at dose rate of 5 kGy h-1 was carried out by simultaneous method under nitrogen atmosphere at room temperature, using gamma rays from a Co-60. After grafting reactions, the polymer was then sulfonated in chlorosulfonic acid/1,2-dichloroethane (2 and 10%) for 3 hours. The films were characterized before and after modification by calculating the degree of grafting (DOG), infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetry (TG/DTG). DOG results show that grafting increases with dose, and varies enormously depending on the solvent used, with DOGs about 20 times greater in DMF than in toluene. It was possible to confirm the grafting of styrene by FT-IR due to the appearance of the new characteristic peaks and by the TG and DSC which exhibited changes in the thermal behavior of the grafted/sulfonated material. Sulfonated material was also characterized by ion exchange capacity (IEC) showed that both DOG and sulfonic acid concentration increase IEC values. Results showed that it is possible to obtain materials with ion exchange capacity of possible application as ionic polymer-metal composites. (author)

Polymer- and salt-induced toroids of hexagonal DNA.

OpenAIRE

Ubbink, J; Odijk, T

1995-01-01

A model is proposed for polymer- and salt-induced toroidal condensates of DNA, based on a recent theory of the undulation enhancement of the electrostatic interaction in the bulk hexagonal phase of semiflexible polyions. In a continuum approximation, the thermodynamic potential of a monomolecular toroid may be split up in bulk, surface, and curvature contributions. With the help of an approximate analytical minimization procedure, the optimal torus dimensions are calculated as a function of t...

Investigation of migrant-polymer interaction in pharmaceutical packaging material using the linear interaction energy algorithm.

Science.gov (United States)

Feenstra, Peter; Brunsteiner, Michael; Khinast, Johannes

2014-10-01

The interaction between drug products and polymeric packaging materials is an important topic in the pharmaceutical industry and often associated with high costs because of the required elaborative interaction studies. Therefore, a theoretical prediction of such interactions would be beneficial. Often, material parameters such as the octanol water partition coefficient are used to predict the partitioning of migrant molecules between a solvent and a polymeric packaging material. Here, we present the investigation of the partitioning of various migrant molecules between polymers and solvents using molecular dynamics simulations for the calculation of interaction energies. Our results show that the use of a model for the interaction between the migrant and the polymer at atomistic detail can yield significantly better results when predicting the polymer solvent partitioning than a model based on the octanol water partition coefficient. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Microscopic theory of light-induced deformation in amorphous side-chain azobenzene polymers.

Science.gov (United States)

Toshchevikov, V; Saphiannikova, M; Heinrich, G

2009-04-16

We propose a microscopic theory of light-induced deformation of side-chain azobenzene polymers taking into account the internal structure of polymer chains. Our theory is based on the fact that interaction of chromophores with the polarized light leads to the orientation anisotropy of azobenzene macromolecules which is accompanied by the appearance of mechanical stress. It is the first microscopic theory which provides the value of the light-induced stress larger than the yield stress. This result explains a possibility for the inscription of surface relief gratings in glassy side-chain azobenzene polymers. For some chemical architectures, elongation of a sample demonstrates a nonmonotonic behavior with the light intensity and can change its sign (a stretched sample starts to be uniaxially compressed), in agreement with experiments. Using a viscoplastic approach, we show that the irreversible strain of a sample, which remains after the light is switched off, decreases with increasing temperature and can disappear at certain temperature below the glass transition temperature. This theoretical prediction is also confirmed by recent experiments.

New materials for polymer electrolyte membrane fuel cell current collectors

Science.gov (United States)

Hentall, Philip L.; Lakeman, J. Barry; Mepsted, Gary O.; Adcock, Paul L.; Moore, Jon M.

Polymer Electrolyte Membrane Fuel cells for automotive applications need to have high power density, and be inexpensive and robust to compete effectively with the internal combustion engine. Development of membranes and new electrodes and catalysts have increased power significantly, but further improvements may be achieved by the use of new materials and construction techniques in the manufacture of the bipolar plates. To show this, a variety of materials have been fabricated into flow field plates, both metallic and graphitic, and single fuel cell tests were conducted to determine the performance of each material. Maximum power was obtained with materials which had lowest contact resistance and good electrical conductivity. The performance of the best material was characterised as a function of cell compression and flow field geometry.

Machining of Machine Elements Made of Polymer Composite Materials

Science.gov (United States)

Baurova, N. I.; Makarov, K. A.

2017-12-01

The machining of the machine elements that are made of polymer composite materials (PCMs) or are repaired using them is considered. Turning, milling, and drilling are shown to be most widely used among all methods of cutting PCMs. Cutting conditions for the machining of PCMs are presented. The factors that most strongly affect the roughness parameters and the accuracy of cutting PCMs are considered.

Photorefractive polymers

NARCIS (Netherlands)

Bolink, Hendrik Jan; Hadziioannou, G

1997-01-01

This thesis describes the synthesis and properties of photorefractive polymers. Photorefractive polymers are materials in which the refractive index can be varied by the interaction with light. Unlike in numerous other photosensitive materials, in photorefractive materials this occurs via

Magnetic polymer-silica composites as bioluminescent sensors for bilirubin detection

Energy Technology Data Exchange (ETDEWEB)

Timin, Alexander S., E-mail: a_timin@mail.ru [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000, Ivanovo (Russian Federation); RASA Center in Tomsk, Tomsk Polytechnic University, pros. Lenina, 30, Tomsk (Russian Federation); Solomonov, Alexey V. [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000, Ivanovo (Russian Federation); Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, 7610001 (Israel); Kumagai, Akiko; Miyawaki, Atsushi [Cell Function Dynamics, Brain Science Institute RIKEN, 2-1 Hirosawa, Wako-city, Saitama, 351-0198 (Japan); Khashirova, Svetlana Yu; Zhansitov, Azamat [Kabardino-Balkar State University, 173 Chernyshevskogo St., Nal' chik, 360004, Kabardino-Balkaria (Russian Federation); Rumyantsev, Evgeniy V. [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000, Ivanovo (Russian Federation)

2016-11-01

The synthesis of multifunctional nano-sized materials is leading to the rapid development of key application, including improved drug delivery, bioimaging and protein separation. In this work, magnetic silica particles modified with novel guanidine containing co-polymers were manufactured via sol-gel method. To evaluate the chemical composition of our prepared samples, FT-IR spectroscopy and thermogravimetry were conducted. Scanning electron microscopy was used in order to investigate the morphology of final products after modification by guanidine containing co-polymers and iron nanoparticles. In addition, the surface of polymer-silica composites was functionalized by the novel bilirubin-inducible fluorescent protein UnaG. In an aqueous bilirubin solution, the silica particles decorated with the polymer-UnaG have showed bright fluorescence. Synthesis and characterization of these hybrid materials allow developing of new multifunctional nano-sized materials, which will be used for detection and separation of bilirubin, a lipophilic heme catabolite that is a clinical diagnostic for liver function. - Highlights: • Novel magnetic silicas grafted by guanidine containing co-polymers were prepared. • Unag protein was effectively loaded into polymer coated silicas. • The fluorescent properties depend on content of bilirubin.

Magnetic polymer-silica composites as bioluminescent sensors for bilirubin detection

International Nuclear Information System (INIS)

Timin, Alexander S.; Solomonov, Alexey V.; Kumagai, Akiko; Miyawaki, Atsushi; Khashirova, Svetlana Yu; Zhansitov, Azamat; Rumyantsev, Evgeniy V.

2016-01-01

The synthesis of multifunctional nano-sized materials is leading to the rapid development of key application, including improved drug delivery, bioimaging and protein separation. In this work, magnetic silica particles modified with novel guanidine containing co-polymers were manufactured via sol-gel method. To evaluate the chemical composition of our prepared samples, FT-IR spectroscopy and thermogravimetry were conducted. Scanning electron microscopy was used in order to investigate the morphology of final products after modification by guanidine containing co-polymers and iron nanoparticles. In addition, the surface of polymer-silica composites was functionalized by the novel bilirubin-inducible fluorescent protein UnaG. In an aqueous bilirubin solution, the silica particles decorated with the polymer-UnaG have showed bright fluorescence. Synthesis and characterization of these hybrid materials allow developing of new multifunctional nano-sized materials, which will be used for detection and separation of bilirubin, a lipophilic heme catabolite that is a clinical diagnostic for liver function. - Highlights: • Novel magnetic silicas grafted by guanidine containing co-polymers were prepared. • Unag protein was effectively loaded into polymer coated silicas. • The fluorescent properties depend on content of bilirubin.

RESTORING A DAMAGED 16-YEAR -OLD INSULATING POLYMER CONCRETE DIKE OVERLAY: REPAIR MATERIALS AND TECHNOLOGIES.

Energy Technology Data Exchange (ETDEWEB)

SUGAMA,T.

2007-01-01

The objective of this program was to design and formulate organic polymer-based material systems suitable for repairing and restoring the overlay panels of insulating lightweight polymer concrete (ILPC) from the concrete floor and slope wall of a dike at KeySpan liquefied natural gas (LNG) facility in Greenpoint, Brooklyn, NY, just over sixteen years ago. It also included undertaking a small-scale field demonstration to ensure that the commercial repairing technologies were applicable to the designed and formulated materials.

A Review on the Fabrication of Polymer-Based Thermoelectric Materials and Fabrication Methods

Science.gov (United States)

Kamarudin, Muhammad Akmal; Sahamir, Shahrir Razey; Datta, Robi Shankar; Long, Bui Duc; Mohd Sabri, Mohd Faizul; Mohd Said, Suhana

2013-01-01

Thermoelectricity, by converting heat energy directly into useable electricity, offers a promising technology to convert heat from solar energy and to recover waste heat from industrial sectors and automobile exhausts. In recent years, most of the efforts have been done on improving the thermoelectric efficiency using different approaches, that is, nanostructuring, doping, molecular rattling, and nanocomposite formation. The applications of thermoelectric polymers at low temperatures, especially conducting polymers, have shown various advantages such as easy and low cost of fabrication, light weight, and flexibility. In this review, we will focus on exploring new types of polymers and the effects of different structures, concentrations, and molecular weight on thermoelectric properties. Various strategies to improve the performance of thermoelectric materials will be discussed. In addition, a discussion on the fabrication of thermoelectric devices, especially suited to polymers, will also be given. Finally, we provide the challenge and the future of thermoelectric polymers, especially thermoelectric hybrid model. PMID:24324378

On nature of spontaneous elongation of polymers preliminarily stretched in adsorption-active media under irradiation

International Nuclear Information System (INIS)

Sinevich, E.A.; Prazdnichnyj, A.M.; Tikhomirov, V.S.; Bakeev, N.F.

1989-01-01

The nature of the spontaneous elongation under irradiation with fast electrons of polymers preliminary stretched in adsorption-active media has been studied. This effect is related with radiation-induced heating of microporous polymer samples. Its manifestation in amorphous PETP requires the presence of crazes having well developed microfibrillar structure. The spontaneous elongation effect is shown to be a result of crystallization of partially oriented material in transitional regions relating the oriented material of microfibrils inside crazes with nonstrained polymer between them

Ultra-high polarity ceramics induced extrinsic high permittivity of polymers contributing to high permittivity of 2-2 series composites

Science.gov (United States)

Feng, Yefeng; Zhang, Jianxiong; Hu, Jianbing; Peng, Cheng; He, Renqi

2018-01-01

Induced polarization at interface has been confirmed to have significant impact on the dielectric properties of 2-2 series composites bearing Si-based semi-conductor sheet and polymer layer. By compositing, the significantly elevated high permittivity in Si-based semi-conductor sheet should be responsible for the obtained high permittivity in composites. In that case, interface interaction could include two aspects namely a strong electrostatic force from high polarity polymeric layer and a newborn high polarity induced in Si-based ceramic sheet. In this work, this class of interface induced polarization was successfully extended into another 2-2 series composite system made up of ultra-high polarity ceramic sheet and high polarity polymer layer. By compositing, the greatly improved high permittivity in high polarity polymer layer was confirmed to strongly contribute to the high permittivity achieved in composites. In this case, interface interaction should consist of a rather large electrostatic force from ultra-high polarity ceramic sheet with ionic crystal structure and an enhanced high polarity induced in polymer layer based on a large polarizability of high polarity covalent dipoles in polymer. The dielectric and conductive properties of four designed 2-2 series composites and their components have been detailedly investigated. Increasing of polymer inborn polarity would lead to a significant elevating of polymer overall polarity in composite. Decline of inherent polarities in two components would result in a mild improving of polymer total polarity in composite. Introducing of non-polarity polymeric layer would give rise to a hardly unaltered polymer overall polarity in composite. The best 2-2 composite could possess a permittivity of ˜463 at 100 Hz 25.7 times of the original permittivity of polymer in it. This work might offer a facile route for achieving the promising composite dielectrics by constructing the 2-2 series samples from two high polarity

Polymer-Particle Nanocomposites: Size and Dispersion Effects

Science.gov (United States)

Moll, Joseph

Polymer-particle nanocomposites are used in industrial processes to enhance a broad range of material properties (e.g. mechanical, optical, electrical and gas permeability properties). This dissertation will focus on explanation and quantification of mechanical property improvements upon the addition of nanoparticles to polymeric materials. Nanoparticles, as enhancers of mechanical properties, are ubiquitous in synthetic and natural materials (e.g. automobile tires, packaging, bone), however, to date, there is no thorough understanding of the mechanism of their action. In this dissertation, silica (SiO2) nanoparticles, both bare and grafted with polystyrene (PS), are studied in polymeric matrices. Several variables of interest are considered, including particle dispersion state, particle size, length and density of grafted polymer chains, and volume fraction of SiO2. Polymer grafted nanoparticles behave akin to block copolymers, and this is critically leveraged to systematically vary nanoparticle dispersion and examine its role on the mechanical reinforcement in polymer based nanocomposites in the melt state. Rheology unequivocally shows that reinforcement is maximized by the formation of a transient, but long-lived, percolating polymer-particle network with the particles serving as the network junctions. The effects of dispersion and weight fraction of filler on nanocomposite mechanical properties are also studied in a bare particle system. Due to the interest in directional properties for many different materials, different means of inducing directional ordering of particle structures are also studied. Using a combination of electron microscopy and x-ray scattering, it is shown that shearing anisotropic NP assemblies (sheets or strings) causes them to orient, one in front of the other, into macroscopic two-dimensional structures along the flow direction. In contrast, no such flow-induced ordering occurs for well dispersed NPs or spherical NP aggregates! This work

Cluster analysis of polymers using laser-induced breakdown spectroscopy with K-means

Science.gov (United States)

Yangmin, GUO; Yun, TANG; Yu, DU; Shisong, TANG; Lianbo, GUO; Xiangyou, LI; Yongfeng, LU; Xiaoyan, ZENG

2018-06-01

Laser-induced breakdown spectroscopy (LIBS) combined with K-means algorithm was employed to automatically differentiate industrial polymers under atmospheric conditions. The unsupervised learning algorithm K-means were utilized for the clustering of LIBS dataset measured from twenty kinds of industrial polymers. To prevent the interference from metallic elements, three atomic emission lines (C I 247.86 nm , H I 656.3 nm, and O I 777.3 nm) and one molecular line C–N (0, 0) 388.3 nm were used. The cluster analysis results were obtained through an iterative process. The Davies–Bouldin index was employed to determine the initial number of clusters. The average relative standard deviation values of characteristic spectral lines were used as the iterative criterion. With the proposed approach, the classification accuracy for twenty kinds of industrial polymers achieved 99.6%. The results demonstrated that this approach has great potential for industrial polymers recycling by LIBS.

Effect of sterilization procedures on properties of plasma polymers relevant to biomedical applications

International Nuclear Information System (INIS)

Artemenko, A.; Kylián, O.; Choukourov, A.; Gordeev, I.; Petr, M.; Vandrovcová, M.; Polonskyi, O.; Bačáková, L.; Slavinska, D.; Biederman, H.

2012-01-01

This study is focused on the evaluation of resistance of plasma polymers toward common sterilization techniques, i.e. property important for possible use of such materials in biomedical applications. Three kinds of plasma polymers having different bioadhesive natures were studied: plasma polymerized poly(ethylene oxide), fluorocarbon plasma polymers, and nitrogen-rich plasma polymers. These plasma polymers were subjected to dry heat, autoclave and UV radiation treatment. Their physical, chemical and bioresponsive properties were determined by means of different techniques (ellipsometry, atomic force microscopy, wettability measurements, X-ray photoelectron spectroscopy and biological tests with osteoblast-like cells MG63). The results clearly show that properties of thin films of plasma polymers may be significantly altered by a sterilization process. Moreover, observed changes induced by selected sterilization methods were found to depend strongly on the sterilized plasma polymer. - Highlights: ► Effect of common sterilization methods on three kinds of plasma polymers is studied. ► Physical, chemical and bioresponsive properties of plasma polymers are analyzed. ► Changes induced by sterilization depend strongly on type of the plasma polymer.

Thermotropic and Thermochromic Polymer Based Materials for Adaptive Solar Control

Directory of Open Access Journals (Sweden)

Olaf Mühling

2010-12-01

Full Text Available The aim of this review is to present the actual status of development in adaptive solar control by use of thermotropic and organic thermochromic materials. Such materials are suitable for application in smart windows. In detail polymer blends, hydrogels, resins, and thermoplastic films with a reversible temperature-dependent switching behavior are described. A comparative evaluation of the concepts for these energy efficient materials is given as well. Furthermore, the change of strategy from ordinary shadow systems to intrinsic solar energy reflection materials based on phase transition components and a first remark about their realization is reported. Own current results concerning extruded films and high thermally stable casting resins with thermotropic properties make a significant contribution to this field.

Biostable scaffolds of polyacrylate polymers implanted in the articular cartilage induce hyaline-like cartilage regeneration in rabbits.

Science.gov (United States)

Sancho-Tello, María; Forriol, Francisco; Martín de Llano, José J; Antolinos-Turpin, Carmen; Gómez-Tejedor, José A; Gómez Ribelles, José L; Carda, Carmen

2017-07-05

To study the influence of scaffold properties on the organization of in vivo cartilage regeneration. Our hypothesis was that stress transmission to the cells seeded inside the pores of the scaffold or surrounding it, which is highly dependent on the scaffold properties, determines the differentiation of both mesenchymal cells and dedifferentiated autologous chondrocytes. 4 series of porous scaffolds made of different polyacrylate polymers, previously seeded with cultured rabbit chondrocytes or without cells, were implanted in cartilage defects in rabbits. Subchondral bone was injured during the surgery to allow blood to reach the implantation site and fill the scaffold pores. At 3 months after implantation, excellent tissue regeneration was obtained, with a well-organized layer of hyaline-like cartilage at the condylar surface in most cases of the hydrophobic or slightly hydrophilic series. The most hydrophilic material induced the poorest regeneration. However, no statistically significant difference was observed between preseeded and non-preseeded scaffolds. All of the materials used were biocompatible, biostable polymers, so, in contrast to some other studies, our results were not perturbed by possible effects attributable to material degradation products or to the loss of scaffold mechanical properties over time due to degradation. Cartilage regeneration depends mainly on the properties of the scaffold, such as stiffness and hydrophilicity, whereas little difference was observed between preseeded and non-preseeded scaffolds.

Preparation of nanocrystalline iron-carbon materials as fillers for polymers

International Nuclear Information System (INIS)

Narkiewicz, U; Pelech, I; Roslaniec, Z; Kwiatkowska, M; Arabczyk, W

2007-01-01

This paper presents a method of preparing nanocrystalline iron-carbon materials which can be applied as fillers for polymers. Nanocrystalline iron samples were carburized either under ethylene/hydrogen mixture or under pure ethylene. Three kinds of samples were prepared: cementite/carbon (Fe 3 C/C), iron/cementite (Fe/Fe 3 C) and iron/carbon (Fe/C) ones. After carburization the samples were characterized using XRD and SEM methods. The obtained samples of iron-carbon nanoparticles were applied as fillers to polymer nanocomposites prepared in a polycondensation reaction (in situ) in a poly(ether-ester) matrix. The nanofillers were dispersed in monomers (diols) using a sonificator and a high-speed rotary stirrer. The obtained nanocomposites were characterized as regards their structure (SEM method) and mechanical behaviour

Elucidation of polymer induced DNA condensation. Visualisation at the single molecular level

International Nuclear Information System (INIS)

Martin, Alison Laura

2002-01-01

DNA condensation is a phenomenon that has stimulated interest from biologists, physicists, and polymer chemists for decades. At the cellular level, this process is key to the packing of DNA within the nuclear envelope, and the exposure of the appropriate nucleic acid sequences in order for transcription to occur, and proteins to be produced. The advent of gene therapy has led to an invigoration of this subject area. In order to successfully deliver to, and transfect target cells, many delivery vectors condense the therapeutic DNA into small compact particles. The nature of these particles have a considerable influence on the ultimate expression of the administered nucleic acid material. In addition, at its most fundamental, DNA itself is a classical polyelectrolyte polymer, the behaviour of which has applicability to other charged polymeric systems. There are two core interwound themes to this investigation; the visualisation of DNA condensate morphology at ultra-resolution, and the elucidation of the mechanisms of formation of these structures. The technique of atomic force microscopy is central to these investigations. Methodologies have been devised allowing the visualisation of the tertiary structure and conformational behaviour of individual DNA condensates in near in situ conditions. Condensation of the nucleic acid material has been induced by two classes of cation; small molecular cations, like those found within eukaryotic cells, and a range of cationic polymers. The cationic polymers investigated all have considerable potential as gene delivery vectors. The resultant DNA condensates have been assessed and contrasted in terms of their tertiary morphology, lateral dimensions, and structural volume. Assessments have also been made regarding the influence of the molecular architecture of the cationic moiety and the nature of the input nucleic acid material on the resultant DNA condensates. With regard to the elucidation of the mechanisms of DNA condensate

Electrosynthesis and catalytic activity of polymer-nickel particles composite electrode materials

International Nuclear Information System (INIS)

Melki, Tahar; Zouaoui, Ahmed; Bendemagh, Barkahoum; Oliveira, Ione M.F. de; Oliveira, Gilver F. de; Lepretre, Jean-Claude; Bucher, Christophe; Mou tet, Jean-Claude

2009-01-01

Nickel-polymer composite electrode materials have been synthesized using various strategies, all comprising the electrochemical reduction of nickel(II) cations or complexes, incorporated by either ion-exchange or complexation into various poly(pyrrole-carboxylate) thin films coated by oxidative electropolymerization onto carbon electrodes. The electrocatalytic activity and the stability of the different composites have been then evaluated in the course of the electrocatalytic hydrogenation of ketones and enones in aqueous electrolytes. The best results were obtained using nickel-polymer composites synthesized by electroreduction of nickel(II) ions complexed into polycarboxylate films, which are characterized by a high catalytic activity and a good operational stability. (author)

Electrosynthesis and catalytic activity of polymer-nickel particles composite electrode materials

Energy Technology Data Exchange (ETDEWEB)

Melki, Tahar; Zouaoui, Ahmed; Bendemagh, Barkahoum [Universite Ferhat Abbas, Setif (Algeria). Faculte des Sciences de l' Ingenieur. Dept. du Tronc Commun; Oliveira, Ione M.F. de; Oliveira, Gilver F. de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Quimica; Lepretre, Jean-Claude [UMR-5631 CNRS-INPG-UJF, St. Martin d' Heres Cedex (France). Lab. d' Electrochimie et de Physicochimie des Materiaux et Interfaces; Bucher, Christophe; Mou tet, Jean-Claude [Universite Joseph Fourier Grenoble 1 (France). Dept. de Chimie Moleculaire], e-mail: Jean-Claude.Moutet@ujf-grenoble.fr

2009-07-01

Nickel-polymer composite electrode materials have been synthesized using various strategies, all comprising the electrochemical reduction of nickel(II) cations or complexes, incorporated by either ion-exchange or complexation into various poly(pyrrole-carboxylate) thin films coated by oxidative electropolymerization onto carbon electrodes. The electrocatalytic activity and the stability of the different composites have been then evaluated in the course of the electrocatalytic hydrogenation of ketones and enones in aqueous electrolytes. The best results were obtained using nickel-polymer composites synthesized by electroreduction of nickel(II) ions complexed into polycarboxylate films, which are characterized by a high catalytic activity and a good operational stability. (author)

Protein cages and synthetic polymers: a fruitful symbiosis for drug delivery applications, bionanotechnology and materials science.

Science.gov (United States)

Rother, Martin; Nussbaumer, Martin G; Renggli, Kasper; Bruns, Nico

2016-11-07

materials, by forming two- and three-dimensional crystals of protein cages and dendrimers, by adsorbing proteins to the surface of materials, by layer-by-layer deposition of proteins and polyelectrolytes and by encapsulating polymers into protein cages. The application of these hybrid materials in the biomedical context or as tools and building blocks for bionanotechnology, biosensing, memory devices and the synthesis of materials will be highlighted. The review aims to showcase recent developments in this field and to suggest possible future directions and opportunities for the symbiosis of protein cages and polymers.

Comparison of Properties of Polymer Composite Materials Reinforced with Carbon Nanotubes

Directory of Open Access Journals (Sweden)

Zygoń P.

2015-04-01

Full Text Available Carbon nanotubes because of their high mechanical, optical or electrical properties, have found use as semiconducting materials constituting the reinforcing phase in composite materials. The paper presents the results of the studies on the mechanical properties of polymer composites reinforced with carbon nanotubes (CNT. Three-point bending tests were carried out on the composites. The density of each obtained composite was determined as well as the surface roughness and the resistivity at room temperature.

Microwave Measurements of Ferrite Polymer Composite Materials

Directory of Open Access Journals (Sweden)

Rastislav Dosoudil

2004-01-01

Full Text Available The article focuses on the microwave measurements performed on the nickel-zinc sintered ferrite with the chemical formula Ni0.3Zn0.7Fe2O4 produced by the ceramic technique and composite materials based on this ferrite and a non-magnetic polymer (polyvinyl chloride matrix. The prepared composite samples had the same particle size distribution 0-250um but different ferrite particle concentrations between 23 vol% and 80 vol%. The apparatus for measurement of the signal proportional to the absolute value of scattering parameter S11 (reflexion coefficient is described and the dependence of measured reflected signal on a bias magnetic field has been studied. By means of experiments, the resonances to be connected with the geometry of microwave experimental set-up were distinguished from ferromagnetic resonance arising in ferrite particles of composite structure. The role of local interaction fields of ferrite particles in composite material has been discussed.

Polymer Industrial Floors - The Possibility of Using Secondary Raw Materials from Solar Panels

OpenAIRE

J. Kosikova; B. Vacenovska; M. Vyhnankova

2014-01-01

The paper reports on the subject of recycling and further use of secondary raw materials obtained from solar panels, which is becoming a very up to date topic in recent years. Recycling these panels is very difficult and complex, and the use of resulting secondary raw materials is still not fully resolved. Within the research carried out at the Brno University of Technology, new polymer materials used for industrial floors are being developed. Secondary raw materials are ...

Microwave Absorbent Packaging Material from Composites Chitosan-Polyvinyl Alcohol Polymer

Directory of Open Access Journals (Sweden)

Bambang - Riyanto

2014-11-01

Full Text Available Microwave absorbent packaging materials currently tend to biomaterial. Chitosan is a dielectric biomaterial with polycationic properties. The aim of this study was to analyze characteristics of microwave absorbing packaging material made from composite chitosan-polyvinyl alcohol (PVA polymer. The ability of the packaging material to absorb microwave was determined by reflection loss measurement. Formed packaging prototype resembles as a thin transparent yellowish plastic with thickness (0.11-0.22 mm and the tensile strength (106.33±2.82-143.00±2.59 kPa. SEM analysis showed homogenous structure characterized by interaction between chitosan and PVA. Optimum absorption value was obtained from chitosan concentration of 1%, with average value of reflection loss was (-31.9289±4.0094 dB.Keywords: chitosan, material packaging, microwave, reflection loss

Microwave Absorbent Packaging Material from Composites Chitosan-Polyvinyl Alcohol Polymer

Directory of Open Access Journals (Sweden)

Bambang - Riyanto

2015-07-01

Full Text Available Microwave absorbent packaging materials currently tend to biomaterial. Chitosan is a dielectric biomaterial with polycationic properties. The aim of this study was to analyze characteristics of microwave absorbing packaging material made from composite chitosan-polyvinyl alcohol (PVA polymer. The ability of the packaging material to absorb microwave was determined by reflection loss measurement. Formed packaging prototype resembles as a thin transparent yellowish plastic with thickness (0.11-0.22 mm and the tensile strength (106.33±2.82-143.00±2.59 kPa. SEM analysis showed homogenous structure characterized by interaction between chitosan and PVA. Optimum absorption value was obtained from chitosan concentration of 1%, with average value of reflection loss was (-31.9289±4.0094 dB.Keywords: chitosan, material packaging, microwave, reflection loss

Use of radiation-induced polymers as temporary or permanent diverting agent

International Nuclear Information System (INIS)

Knight, B.L.; Rhudy, J.S.; Gogarty, W.B.

1975-01-01

Temporary or permanent permeability reduction or plugging of porous medium to the flow of fluids is effected by treating, preferably by injecting under pressure into the pores, the porous medium with an aqueous solution containing a water-soluble polymer obtained as a product of radiation-induced polymerization of acrylamide and/or methacrylamide and acrylic acid, methacrylic acid, and/or alkali metal salts thereof. The polymer has sufficient properties to effect substantial permeability reduction of the porous medium. The polymerization is preferably carried out in 10 to 60 percent aqueous monomer solution with gamma radiation. A mixture of monomers, before radiation preferably contain 25 to 99 percent acrylamide and 75 to 1 percent sodium acrylate. Permeability can be restored by subsequently treating the porous medium with a chemical to break down the polymer, e.g., hydrazine hypochlorite solution, strong mineral acids, or bases. (U.S.)

Biodegradable Polymers

OpenAIRE

Vroman, Isabelle; Tighzert, Lan

2009-01-01

Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources) or from biological resources (renewable resources). In general natural polymers offer fewer advantages than synthetic polymers. ...

Impregnation and Polymerization Methods and Systems Used in the Production of Wood-Polymer Materials

Energy Technology Data Exchange (ETDEWEB)

Mott, W. E.; Rotariu, G. J. [United States Atomic Energy Commission, Washington, DC 20545 (United States)

1968-10-15

Studies on the radiation production of wood-polymer materials began in the United States in 1961 at West Virginia University and have continued until today. In this paper the impregnation and polymerization methods and systems that have evolved from these studies are reviewed. Included is a description of the procedures developed at the College of Forestry, Syracuse University, for producing wood-polymers via a thermal-catalytic process. (author)

Artificially Engineered Protein Polymers.

Science.gov (United States)

Yang, Yun Jung; Holmberg, Angela L; Olsen, Bradley D

2017-06-07

Modern polymer science increasingly requires precise control over macromolecular structure and properties for engineering advanced materials and biomedical systems. The application of biological processes to design and synthesize artificial protein polymers offers a means for furthering macromolecular tunability, enabling polymers with dispersities of ∼1.0 and monomer-level sequence control. Taking inspiration from materials evolved in nature, scientists have created modular building blocks with simplified monomer sequences that replicate the function of natural systems. The corresponding protein engineering toolbox has enabled the systematic development of complex functional polymeric materials across areas as diverse as adhesives, responsive polymers, and medical materials. This review discusses the natural proteins that have inspired the development of key building blocks for protein polymer engineering and the function of these elements in material design. The prospects and progress for scalable commercialization of protein polymers are reviewed, discussing both technology needs and opportunities.

RF electromagnetic wave absorbing properties of ferrite polymer composite materials

International Nuclear Information System (INIS)

Dosoudil, Rastislav; Usakova, Marianna; Franek, Jaroslav; Slama, Jozef; Olah, Vladimir

2006-01-01

The frequency dispersion of complex initial (relative) permeability (μ * =μ ' -jμ ' ') and the electromagnetic wave absorbing properties of composite materials based on NiZn sintered ferrite and a polyvinylchloride (PVC) polymer matrix have been studied in frequency range from 1MHz to 1GHz. The complex permeability of the composites was found to increase as the ferrite content increased, and was characterized by frequency dispersion localized above 50MHz. The variation of return loss (RL) of single-layer RF absorbers using the prepared composite materials has been investigated as a function of frequency, ferrite content and the thickness of the absorbers

Microtensile Bond Strength of New Ceramic/Polymer Materials Repaired with Composite Resin

Science.gov (United States)

2015-06-30

also have been shown to have higher enamel wear rates than composite-resin CAD/CAM restorations (Mӧrmann et al, 2013). As material choices, cost, and...although the longevity of these repairs has not been validated by clinical studies. Paradigm MZ100 showed the least amount of opposing enamel wear...ability to absorb shock, resist staining and stop crack propagation. Further manufacturer claims are that ceramic/polymer materials are easily

Study on dissolution behavior of polymer-bound and polymer-blended photo-acid generator (PAG) resists

Science.gov (United States)

Yamamoto, Hiroki; Kozawa, Takahiro; Tagawa, Seiichi

2013-03-01

The requirements for the next generation resist materials are so challenging that it is indispensable for feasibility of EUV lithography to grasp basic chemistry of resist matrices in all stage of resist processes. Under such circumstances, it is very important to know dissolution characteristics of the resist film into alkaline developer though the dissolution of exposed area of resist films in alkaline developer to form a pattern is a complex reactive process. In this study, the influence of EUV and KrF exposure on the dissolution behavior of polymer bound PAG and polymer blended PAG was studied in detail using quartz crystal microbalance (QCM) methods. The difference in swelling formation between KrF and EUV exposure was observed. It is likely that difference of reaction mechanism induces the difference of these swelling. Also, it is observed that the swelling of polymer-bound PAG is less than that of polymer blended PAG in both KrF and EUV exposure. This result indicates that polymer-bound PAG suppresses swelling very well and showed an excellent performance. Actually, the developed polymer bound-PAG resist showed an excellent performance (half pitch 50 nm line and space pattern). Thus, polymer bound PAG is one of the promising candidate for 16 nm EUV resist.

Fabrication of Micrometer- and Nanometer-Scale Polymer Structures by Visible Light Induced Dielectrophoresis (DEP Force

Directory of Open Access Journals (Sweden)

Wen J. Li

2011-12-01

Full Text Available We report in this paper a novel, inexpensive and flexible method for fabricating micrometer- and nanometer-scale three-dimensional (3D polymer structures using visible light sources instead of ultra-violet (UV light sources or lasers. This method also does not require the conventional micro-photolithographic technique (i.e., photolithographic masks for patterning and fabricating polymer structures such as hydrogels. The major materials and methods required for this novel fabrication technology are: (1 any cross-linked network of photoactive polymers (examples of fabricated poly(ethylene glycol (PEG-diacrylate hydrogel structures are shown in this paper; (2 an Optically-induced Dielectrophoresis (ODEP System which includes an “ODEP chip” (i.e., any chip that changes its surface conductivity when exposed to visible light, an optical microscope, a projector, and a computer; and (3 an animator software hosted on a computer that can generate virtual or dynamic patterns which can be projected onto the “ODEP chip” through the use of a projector and a condenser lens. Essentially, by placing a photosensitive polymer solution inside the microfluidic platform formed by the “ODEP chip” bonded to another substrate, and applying an alternating current (a.c. electrical potential across the polymer solution (typically ~20 Vp-p at 10 kHz, solid polymer micro/nano structures can then be formed on the “ODEP chip” surface when visible-light is projected onto the chip. The 2D lateral geometry (x and y dimensions and the thickness (height of the micro/nano structures are dictated by the image geometry of the visible light projected onto the “ODEP chip” and also the time duration of projection. Typically, after an image projection with intensity ranging from ~0.2 to 0.4 mW/cm2 for 10 s, ~200 nm high structures can be formed. In our current system, the thickness of these polymer structures can be controlled to form from ~200 nanometers to ~3

Aerogels of 1D Coordination Polymers: From a Non-Porous Metal-Organic Crystal Structure to a Highly Porous Material

Directory of Open Access Journals (Sweden)

Adrián Angulo-Ibáñez

2016-01-01

Full Text Available The processing of an originally non-porous 1D coordination polymer as monolithic gel, xerogel and aerogel is reported as an alternative method to obtain novel metal-organic porous materials, conceptually different to conventional crystalline porous coordination polymer (PCPs or metal-organic frameworks (MOFs. Although the work herein reported is focused upon a particular kind of coordination polymer ([M(μ-ox(4-apy2]n, M: Co(II, Ni(II, the results are of interest in the field of porous materials and of MOFs, as the employed synthetic approach implies that any coordination polymer could be processable as a mesoporous material. The polymerization conditions were fixed to obtain stiff gels at the synthesis stage. Gels were dried at ambient pressure and at supercritical conditions to render well shaped monolithic xerogels and aerogels, respectively. The monolithic shape of the synthesis product is another remarkable result, as it does not require a post-processing or the use of additives or binders. The aerogels of the 1D coordination polymers are featured by exhibiting high pore volumes and diameters ranging in the mesoporous/macroporous regions which endow to these materials the ability to deal with large-sized molecules. The aerogel monoliths present markedly low densities (0.082–0.311 g·cm−3, an aspect of interest for applications that persecute light materials.

Electrically actuatable doped polymer flakes and electrically addressable optical devices using suspensions of doped polymer flakes in a fluid host

Science.gov (United States)

Trajkovska-Petkoska, Anka; Jacobs, Stephen D.; Marshall, Kenneth L.; Kosc, Tanya Z.

2010-05-11

Doped electrically actuatable (electrically addressable or switchable) polymer flakes have enhanced and controllable electric field induced motion by virtue of doping a polymer material that functions as the base flake matrix with either a distribution of insoluble dopant particles or a dopant material that is completely soluble in the base flake matrix. The base flake matrix may be a polymer liquid crystal material, and the dopants generally have higher dielectric permittivity and/or conductivity than the electrically actuatable polymer base flake matrix. The dopant distribution within the base flake matrix may be either homogeneous or non-homogeneous. In the latter case, the non-homogeneous distribution of dopant provides a dielectric permittivity and/or conductivity gradient within the body of the flakes. The dopant can also be a carbon-containing material (either soluble or insoluble in the base flake matrix) that absorbs light so as to reduce the unpolarized scattered light component reflected from the flakes, thereby enhancing the effective intensity of circularly polarized light reflected from the flakes when the flakes are oriented into a light reflecting state. Electro-optic devices contain these doped flakes suspended in a host fluid can be addressed with an applied electric field, thus controlling the orientation of the flakes between a bright reflecting state and a non-reflecting dark state.

In silico design of porous polymer networks: high-throughput screening for methane storage materials.

Science.gov (United States)

Martin, Richard L; Simon, Cory M; Smit, Berend; Haranczyk, Maciej

2014-04-02

Porous polymer networks (PPNs) are a class of advanced porous materials that combine the advantages of cheap and stable polymers with the high surface areas and tunable chemistry of metal-organic frameworks. They are of particular interest for gas separation or storage applications, for instance, as methane adsorbents for a vehicular natural gas tank or other portable applications. PPNs are self-assembled from distinct building units; here, we utilize commercially available chemical fragments and two experimentally known synthetic routes to design in silico a large database of synthetically realistic PPN materials. All structures from our database of 18,000 materials have been relaxed with semiempirical electronic structure methods and characterized with Grand-canonical Monte Carlo simulations for methane uptake and deliverable (working) capacity. A number of novel structure-property relationships that govern methane storage performance were identified. The relationships are translated into experimental guidelines to realize the ideal PPN structure. We found that cooperative methane-methane attractions were present in all of the best-performing materials, highlighting the importance of guest interaction in the design of optimal materials for methane storage.

Shape memory polymer medical device

Science.gov (United States)

Maitland, Duncan [Pleasant Hill, CA; Benett, William J [Livermore, CA; Bearinger, Jane P [Livermore, CA; Wilson, Thomas S [San Leandro, CA; Small, IV, Ward; Schumann, Daniel L [Concord, CA; Jensen, Wayne A [Livermore, CA; Ortega, Jason M [Pacifica, CA; Marion, III, John E.; Loge, Jeffrey M [Stockton, CA

2010-06-29

A system for removing matter from a conduit. The system includes the steps of passing a transport vehicle and a shape memory polymer material through the conduit, transmitting energy to the shape memory polymer material for moving the shape memory polymer material from a first shape to a second and different shape, and withdrawing the transport vehicle and the shape memory polymer material through the conduit carrying the matter.

Polymer-encapsulated metal nanoparticles: optical, structural, micro-analytical and hydrogenation studies of a composite material

International Nuclear Information System (INIS)

Scalzullo, Stefania; Mondal, Kartick; Deshmukh, Amit; Scurrell, Mike; Mallick, Kaushik; Witcomb, Mike

2008-01-01

A single-step synthesis route is described for the preparation of a metal-polymer composite in which palladium acetate and meta-amino benzoic acid were used as the precursors for palladium nanoparticles and poly(meta-amino benzoic acid) (PABA). The palladium nanoparticles were found to be uniformly dispersed and highly stabilized throughout the macromolecule matrix. The resultant composite material was characterized by means of different techniques, such as IR and Raman spectroscopy, which provided information regarding the chemical structure of the polymer, whereas electron microscopy images yielded information regarding the morphology of the composite material and the distribution of the metal particles in the composite material. The composite material was used as a catalyst for the ethylene hydrogenation reaction and showed catalytic activity at higher temperatures. TEM studies confirmed the changed environment of the nanoparticles at these temperatures

Photovoltaic Performance of Inverted Polymer Solar Cells Using Hybrid Carbon Quantum Dots and Absorption Polymer Materials

Science.gov (United States)

Lim, Hwain; Lee, Kyu Seung; Liu, Yang; Kim, Hak Yong; Son, Dong Ick

2018-05-01

We report the synthesis and characterization of the carbon quantum dots (C-dots) easily obtained from citric acid and ethanediamine, and also investigated structural, optical and electrical properties. The C-dots have extraordinary optical and electrical features such as absorption of ultraviolet range and effective interface for charge separation and transport in active layer, which make them attractive materials for applications in photovoltaic devices (PV). The C-dots play important roles in charge extraction in the PV structures, they can be synthesized by a simple method and used to insert in active layer of polymer solar cells. In this study, we demonstrate that improve charge transport properties of inverted polymer solar cells (iPSCs) with C-dots and structural, optical and electrical properties of C-dots. As a result, iPSCs with C-dots showed enhancement of more than 30% compared with that of the contrast device in power conversion efficiency.

Effect of sterilization procedures on properties of plasma polymers relevant to biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Artemenko, A. [Charles University in Prague, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holesovickach 2, 180 00 Prague (Czech Republic); Kylian, O., E-mail: ondrej.kylian@gmail.com [Charles University in Prague, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holesovickach 2, 180 00 Prague (Czech Republic); Choukourov, A.; Gordeev, I.; Petr, M. [Charles University in Prague, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holesovickach 2, 180 00 Prague (Czech Republic); Vandrovcova, M. [Institute of Physiology, Academy of Sciences of the Czech Republic, Department of Growth and Differentiation of Cell Populations, Videnska 1083, 142 20, Prague 4 (Czech Republic); Polonskyi, O. [Charles University in Prague, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holesovickach 2, 180 00 Prague (Czech Republic); Bacakova, L. [Institute of Physiology, Academy of Sciences of the Czech Republic, Department of Growth and Differentiation of Cell Populations, Videnska 1083, 142 20, Prague 4 (Czech Republic); Slavinska, D.; Biederman, H. [Charles University in Prague, Faculty of Mathematics and Physics, Department of Macromolecular Physics, V Holesovickach 2, 180 00 Prague (Czech Republic)

2012-10-01

This study is focused on the evaluation of resistance of plasma polymers toward common sterilization techniques, i.e. property important for possible use of such materials in biomedical applications. Three kinds of plasma polymers having different bioadhesive natures were studied: plasma polymerized poly(ethylene oxide), fluorocarbon plasma polymers, and nitrogen-rich plasma polymers. These plasma polymers were subjected to dry heat, autoclave and UV radiation treatment. Their physical, chemical and bioresponsive properties were determined by means of different techniques (ellipsometry, atomic force microscopy, wettability measurements, X-ray photoelectron spectroscopy and biological tests with osteoblast-like cells MG63). The results clearly show that properties of thin films of plasma polymers may be significantly altered by a sterilization process. Moreover, observed changes induced by selected sterilization methods were found to depend strongly on the sterilized plasma polymer. - Highlights: Black-Right-Pointing-Pointer Effect of common sterilization methods on three kinds of plasma polymers is studied. Black-Right-Pointing-Pointer Physical, chemical and bioresponsive properties of plasma polymers are analyzed. Black-Right-Pointing-Pointer Changes induced by sterilization depend strongly on type of the plasma polymer.

PERMEABILITY, SOLUBILITY, AND INTERACTION OF HYDROGEN IN POLYMERS- AN ASSESSMENT OF MATERIALS FOR HYDROGEN TRANSPORT

Energy Technology Data Exchange (ETDEWEB)

Kane, M

2008-02-05

Fiber-reinforced polymer (FRP) piping has been identified as a leading candidate for use in a transport system for the Hydrogen Economy. Understanding the permeation and leakage of hydrogen through the candidate materials is vital to effective materials system selection or design and development of safe and efficient materials for this application. A survey of the literature showed that little data on hydrogen permeation are available and no mechanistically-based models to quantitatively predict permeation behavior have been developed. However, several qualitative trends in gaseous permeation have been identified and simple calculations have been performed to identify leakage rates for polymers of varying crystallinity. Additionally, no plausible mechanism was found for the degradation of polymeric materials in the presence of pure hydrogen. The absence of anticipated degradation is due to lack of interactions between hydrogen and FRP and very low solubility coefficients of hydrogen in polymeric materials. Recommendations are made to address research and testing needs to support successful materials development and use of FRP materials for hydrogen transport and distribution.

A coordination polymer based magnetic adsorbent material for hemoglobin isolation from human whole blood, highly selective and recoverable

Science.gov (United States)

Zhang, Xiaoxing; Tan, Jipeng; Xu, Xinxin; Shi, Fanian; Li, Guanglu; Yang, Yiqiao

2017-09-01

A composite material has been obtained successfully through the loading of nanoscale coordination polymer on magnetic Fe3O4@SiO2 core-shell particle. In this composite material, coordination polymer nanoparticles distribute uniformly on Fe3O4@SiO2 and these two components are "tied" together firmly with chemical bonds. Adsorption experiments suggest this composite material exhibits very excellent selectivity to hemoglobin. But under the same condition, its adsorption to bovine serum albumin can almost be ignored. This selectivity can be attributed to the existence of hydrophobic interactions between coordination polymer nanoparticle and hemoglobin. For composite material, the hemoglobin adsorption process follows Langmuir model perfectly with high speed. The adsorbed hemoglobin can be eluted easily by sodium dodecyl sulfate stripping reagent with structure and biological activity of hemoglobin keeps well. The composite material was also employed to separate hemoglobin from human whole blood, which receives a very satisfactory result. Furthermore, magnetic measurement reveals ferromagnetic character of this composite material with magnetization saturation 3.56 emu g-1 and this guarantees its excellent magnetic separation performance from the treated solution.

Pore structure, mechanical properties and polymer characteristics of porous materials impregnated with methylmethacrylate

International Nuclear Information System (INIS)

Hastrup, K.

1976-05-01

The pore structure of porous materials plays a decisive role with regard to many properties of the materials. One therefore expects property improvement due to impregnation to be mostly brought about as a result of pore structure modification. This supposition formed the basis for the project here presented, which had the main aim of investigating polymer impregnation in relation to pore structure. Objectives were: 1) to examine the pore structure of hardened cement paste, beech wood and porous glass before and after gas-phase impregnation with methyl-methacrylate monomer and in situ polymerization, 2) to investigate the influence of the pore structure on the molecular weight of the polymer, 3) to investigate the influence of the degree of pore filling on the elastic modulus, damping coefficient and bending strength. (author)

Conservation of ethylene feedstock for the commodity polymer market through the radiation induced production of polyketones and polysulfones

International Nuclear Information System (INIS)

Steinberg, M.

1975-10-01

Because of the increase in cost of foreign oil, ethylene costs have increased markedly within the last several years. There is presently a sizable incentive to reduce raw material cost for basic polymer manufacture. The polyketones, synthesized from ethylene and CO, and the polysulfones, synthesized from ethylene and SO 2 , utilizing high energy radiation, offers one such possibility. The process has the additional advantage in that CO and SO 2 usually considered as wastes and pollutants from fossil fuel burning power plants are converted to useful materials. The polyketones and polysulfones formed from the gas phase below 100 0 C have been found to be high molecular weight polymers which, depending on composition either melt with difficulty, or decompose at temperatures of 250 0 C or higher. The higher temperature (greater than 100 0 C) catalyst-induced reaction produces low molecular weight waxes. Design calculations indicate that for a G value of 10,000 and 50 percent energy deposition efficiency, it would take 331 M Ci of 60 Co to conserve 2 billion pounds of ethylene or 25 percent of the overall U.S. market by substituting CO and SO 2 . This savings amounts to as much as $280 million at today's market price. Electron machine radiation with a 25 percent energy deposition efficiency requires a total beam power of 9800 KW. The use of machine radiation is preferred because of safety, availability, and initial investment. The challenge presented by the development of the described substituted polymer systems, depends on (1) the determination of the uniqueness of the radiation process, and confirming the yields with electron machine radiation, (2) the processability and market acceptability of the substituted polymers, and (3) the ability to design an efficient radiation process reactor

Sonication-induced Ostwald ripening of ZIF-8 nanoparticles and formation of ZIF-8/polymer composite membranes

KAUST Repository

Thompson, Joshua A.

2012-08-01

The effect of typical membrane processing conditions on the structure, interfacial morphology, and gas separation performance of MOF/polymer nanocomposite membranes is investigated. In particular, the ZIF-8/Matrimid® nanocomposite membrane system is examined, and it is shown that ultrasonication - a commonly employed particle dispersion method - induces significant changes in the shape, size distribution, and structure of ZIF-8 particles suspended in an organic solvent during membrane processing. Dynamic light scattering and electron microscopy reveal that ZIF-8 nanoparticles undergo substantial Ostwald ripening when subjected to high intensity ultrasonication as often required in the formation of MOF/polymer nanocomposite membranes. Other characterization techniques reveal that the ripened particles exhibit lower pore volumes and lower surface areas compared to the as-made material. ZIF-8/Matrimid® composite membranes fabricated using two sonication methods show significant differences in microstructure. Permeation measurements show significant enhancement in permeability of CO 2 and increased CO 2/CH 4 selectivity in membranes fabricated with high-intensity sonication. In contrast, composite membranes prepared with low-intensity sonication are found to be defective. A careful evaluation of MOF membrane processing conditions, as well as knowledge of the properties of the MOF material after these membrane processing steps, are necessary to develop reliable processing-structure-property relations for MOF-containing membranes. © 2012 Elsevier Inc. All rights reserved.

Modeling and analysis rheology of polymers for application in technologies “self-crimping” and its adaptation to the practices of Polymer Materials Engineering

OpenAIRE

N. Montanes; L. Sánchez-Nacher; M.J. Reig; O. Fenollar; T. Boronat

2017-01-01

[EN] Polymers are manufactured in molted state, so the rheological properties are mandatory in order to analyzeand evaluate its processability. The prediction of the viscoelastic response of a material and the simulationof the behavior of the same when it is processed is achieved with the application of the rheological models.In the preparation by extrusion of bicomponent polymer bers with self-crimping e ect it is essentialthat the two components have the same viscosity...

Laser-induced ion emission during polymer deposition from a flash-frozen water ice matrix

DEFF Research Database (Denmark)

Rodrigo, K.; Toftmann, Bo; Schou, Jørgen

2004-01-01

Flash-frozen water solutions of 1% weight PEG (polyethylene glycol) at -50 degreesC were used as targets at a laser wavelength of 355 nm for polymer deposition with Matrix-Assisted Pulsed Laser Evaporation (MAPLE). For medium laser fluences the transfer of PEG material to the substrate was accomp......Flash-frozen water solutions of 1% weight PEG (polyethylene glycol) at -50 degreesC were used as targets at a laser wavelength of 355 nm for polymer deposition with Matrix-Assisted Pulsed Laser Evaporation (MAPLE). For medium laser fluences the transfer of PEG material to the substrate...

Formation of compositional gradient profiles by using shear-induced polymer migration phenomenon under Couette flow field

Energy Technology Data Exchange (ETDEWEB)

Im, Sang Hyuk; Lee, Su Jin [Kyung Hee University, Yongin (Korea, Republic of); Suh, Duck Jong; Park, O Ok [Korea Advanced Institute of Science and Technology (KAIST), Daejeon (Korea, Republic of); Kwon, Moo Hyun [Woosuk University, Wanju (Korea, Republic of)

2015-07-15

We investigated whether a graded-index profile, specified by the polymer compositional gradient, could be formed using shear-induced polymer migration phenomenon in a polymer solution. For the presented model system, we generated a shear flow by rotating a glass rod at the center of a polystyrene/methylmethacrylate (PS/MMA) solution and measured the degree of polymer migration by the shear flow field by examining the concentration of polymer solution along the radial direction from the rotating axis to the periphery. Through model experiments, we formed a compositional gradient and controlled its profile in the solution by varying the concentration of polymer solution, molecular weight of polymer, and shear rate. Finally, we solidified the gradient profiles by the polymerization of the PS/MMA solution and confirmed that the gradient profiles were maintained with a compositional gradient twice larger than the mother PS/MMA solution.

The viscoelastic characterization of polymer materials exposed to the low-Earth orbit environment

International Nuclear Information System (INIS)

Strganac, T.; Letton, A.

1992-01-01

Recent accomplishments in our research efforts have included the successful measurement of the thermal mechanical properties of polymer materials exposed to the low-earth orbit environment. In particular, viscoelastic properties were recorded using the Rheometrics Solids Analyzer (RSA 2). Dynamic moduli (E', the storage component of the elastic modulus, and E'', the loss component of the elastic modulus) were recorded over three decades of frequency (0.1 to 100 rad/sec) for temperatures ranging from -150 to 150 C. Although this temperature range extends beyond the typical use range of the materials, measurements in this region are necessary in the development of complete viscoelastic constitutive models. The experimental results were used to provide the stress relaxation and creep compliance performance characteristics through viscoelastic correspondence principles. Our results quantify the differences between exposed and control polymer specimens. The characterization is specifically designed to elucidate a constitutive model that accurately predicts the change in behavior of these materials due to exposure. The constitutive model for viscoelastic behavior reflects the level of strain, the rate of strain, and the history of strain as well as the thermal history of the material

New nanocomposite surfaces and thermal interface materials based on mesoscopic microspheres, polymers and graphene flakes

Science.gov (United States)

Dmitriev, Alex A.; Dmitriev, Alex S.; Makarov, Petr; Mikhailova, Inna

2018-04-01

In recent years, there has been a great interest in the development and creation of new functional energy mate-rials, including for improving the energy efficiency of power equipment and for effectively removing heat from energy devices, microelectronics and optoelectronics (power micro electronics, supercapacitors, cooling of processors, servers and data centers). In this paper, the technology of obtaining new nanocomposites based on mesoscopic microspheres, polymers and graphene flakes is considered. The methods of sequential production of functional materials from graphene flakes of different volumetric concentration using epoxy polymers, as well as the addition of monodisperse microspheres are described. Data are given on the measurement of the contact angle and thermal conductivity of these nanocomposites with respect to the creation of thermal interface materials for cooling devices of electronics, optoelectronics and power engineering.

Laser-induced damage study of polymer PMMA; Motale-e-ye padid-e-ye khesarat-e mavvad-e polimeri PMMA dar moghabel-e barik-e-ye laizer

Energy Technology Data Exchange (ETDEWEB)

Mansour, N

2001-07-01

This article presents the results of bulk laser-induced damage measurements in polymer PMMA at 532 nm and 1064 nm for nanosecond laser pulses. The damage thresholds were measured for focused spot sizes ranging over two orders of magnitude. In this work, self-focusing effects were verified to be absent by measurements of breakdown thresholds using both linearly and circularly polarized light. At both 1064 nm and 532 nm, the dependence of the breakdown field, E{sub B}, on the spot size, {omega}, was empirically determined to be E{sub B} = C/{radical}{omega}, where C depends on the wavelength. The extracted value for C({lambda}) at 1064 nm is larger by a factor of 5 than at 532 nm. Possible reasons for this strong dispersion and mechanism for laser-induced damage in polymer materials will be discussed.

Indaceno-Based Conjugated Polymers for Polymer Solar Cells.

Science.gov (United States)

Yin, Yuli; Zhang, Yong; Zhao, Liancheng

2018-01-04

Polymer solar cells have received considerable attention due to the advantages of low material cost, tunable band gaps, ultralight weight, and high flexible properties, and they have been a promising organic photovoltaic technology for alternative non-renewable fossil fuels for the past decade. Inspired by these merits, numerous state-of-the-art organic photovoltaic materials have been constructed. Among them, indaceno-based polymer materials have made an impact in obtaining an impressive power conversion efficiency of more than 11%, which shows the momentous potential of this class of materials for commercial applications. In this review, recent progress of indaceno-based organic polymer solar cells are reviewed, and the structure-property device performance correlations of the reported materials are highlighted. Then, common regularities of these successful cases are collected, and encouraging viewpoints on the further development of more exciting indaceno-based organic photovoltaic materials are provided. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of biodegradable polymers irradiated with swift heavy ions

International Nuclear Information System (INIS)

Salguero, N.G.; Grosso, M.F. del; Durán, H.; Peruzzo, P.J.; Amalvy, J.I.

2012-01-01

In view of their application as biomaterials, there is an increasing interest in developing new methods to induce controlled cell adhesion onto polymeric materials. The critical step in all these methods involves the modification of polymer surfaces, to induce cell adhesion, without changing theirs degradation and biocompatibility properties. In this work two biodegradable polymers, polyhydroxybutyrate (PHB) and poly-L-lactide acid (PLLA) were irradiated using carbon and sulfur beams with different energies and fluences. Pristine and irradiated samples were degradated by immersion in a phosphate buffer at pH 7.0 and then characterized. The analysis after irradiation and degradation showed a decrease in the contact angle values and changes in their crystallinity properties.

Characterization of biodegradable polymers irradiated with swift heavy ions

Energy Technology Data Exchange (ETDEWEB)

Salguero, N.G. [Gerencia de Investigacion y Aplicaciones, TANDAR-CNEA, Av. Gral. Paz 1499 (B1650KNA) San Martin, Buenos Aires (Argentina); Grosso, M.F. del, E-mail: delgrosso@tandar.cnea.gov.ar [Gerencia de Investigacion y Aplicaciones, TANDAR-CNEA, Av. Gral. Paz 1499 (B1650KNA) San Martin, Buenos Aires (Argentina); CONICET, Av. Rivadavia 1917 C1033AAJ CABA (Argentina); Duran, H. [CONICET, Av. Rivadavia 1917 C1033AAJ CABA (Argentina); Gerencia de Desarrollo Tecnologico y Proyectos Especiales, CNEA, Av. Gral. Paz 1499 (B1650KNA) San Mart Latin-Small-Letter-Dotless-I Acute-Accent n, Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, H. Yrigoyen 3100, CP 1650, San Martin, UNSAM (Argentina); Peruzzo, P.J. [CICPBA - Grupo de Materiales y Nanomateriales Polimericos, Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), CCT La Plata CONICET - Universidad Nacional de La Plata, La Plata (Argentina); Amalvy, J.I. [CICPBA - Grupo de Materiales y Nanomateriales Polimericos, Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), CCT La Plata CONICET - Universidad Nacional de La Plata, La Plata (Argentina); Facultad de Ingenieria, Universidad Nacional de La Plata, Calle 116 y 48 (B1900TAG), La Plata (Argentina); Departamento de Ingenieria Quimica, Facultad Regional La Plata, Universidad Tecnologica Nacional, 60 y 124 (1900), La Plata (Argentina); and others

2012-02-15

In view of their application as biomaterials, there is an increasing interest in developing new methods to induce controlled cell adhesion onto polymeric materials. The critical step in all these methods involves the modification of polymer surfaces, to induce cell adhesion, without changing theirs degradation and biocompatibility properties. In this work two biodegradable polymers, polyhydroxybutyrate (PHB) and poly-L-lactide acid (PLLA) were irradiated using carbon and sulfur beams with different energies and fluences. Pristine and irradiated samples were degradated by immersion in a phosphate buffer at pH 7.0 and then characterized. The analysis after irradiation and degradation showed a decrease in the contact angle values and changes in their crystallinity properties.

Flow-induced correlation effects within a linear chain in a polymer melt

NARCIS (Netherlands)

Stepanyan, R.; Slot, J.J.M.; Molenaar, J.; Tchesnokov, M.A.

2005-01-01

A framework for a consistent description of the flow-induced correlation effects within a linear polymer chain in a melt is proposed. The formalism shows how correlations between chain segments in the flow can be incorporated into a hierarchy of distribution functions for tangent vectors. The

Cellular Automata Modelling of Photo-Induced Oxidation Processes in Molecularly Doped Polymers

Directory of Open Access Journals (Sweden)

David M. Goldie

2016-11-01

Full Text Available The possibility of employing cellular automata (CA to model photo-induced oxidation processes in molecularly doped polymers is explored. It is demonstrated that the oxidation dynamics generated using CA models exhibit stretched-exponential behavior. This dynamical characteristic is in general agreement with an alternative analysis conducted using standard rate equations provided the molecular doping levels are sufficiently low to prohibit the presence of safe-sites which are impenetrable to dissolved oxygen. The CA models therefore offer the advantage of exploring the effect of dopant agglomeration which is difficult to assess from standard rate equation solutions. The influence of UV-induced bleaching or darkening upon the resulting oxidation dynamics may also be easily incorporated into the CA models and these optical effects are investigated for various photo-oxidation product scenarios. Output from the CA models is evaluated for experimental photo-oxidation data obtained from a series of hydrazone-doped polymers.

Polymer-free graphene transfer for enhanced reliability of graphene field-effect transistors

International Nuclear Information System (INIS)

Park, Hamin; Park, Ick-Joon; Jung, Dae Yool; Lee, Khang June; Yang, Sang Yoon; Choi, Sung-Yool

2016-01-01

We propose a polymer-free graphene transfer technique for chemical vapor deposition-grown graphene to ensure the intrinsic electrical properties of graphene for reliable transistor applications. The use of a metal catalyst as a supporting layer avoids contamination from the polymer material and graphene films become free of polymer residue after the transfer process. Atomic force microscopy and Raman spectroscopy indicate that the polymer-free transferred graphene shows closer properties to intrinsic graphene properties. The reliability of graphene field-effect transistors (GFETs) was investigated through the analysis of the negative gate bias-stress-induced instability. This work reveals the effect of polymer residues on the reliability of GFETs, and that the developed new polymer-free transfer method enhances the reliability. (letter)

Process comparison for fracture-induced formation of surface structures on polymer films

Energy Technology Data Exchange (ETDEWEB)

Lee, Yueh-Ying [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Yang, Fuqian [Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506 (United States); Chen, Chia-Chieh [Institute of Nuclear Energy Research, Longtan, Taoyuan 32546, Taiwan (China); Lee, Sanboh, E-mail: sblee@mx.nthu.edu.tw [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

2014-01-01

Using three different splitting approaches such as point-load splitting, tension-splitting and peeling–splitting, different surface ripples were produced on poly(methyl methacrylate) (PMMA)-based polymer films. Independent of the splitting approaches, the spatial wavelength of the surface structures is a linear function of the film thickness with the approximately same differential ratio of the spatial wavelength to the film thickness. The apparent surface residual stress was calculated from the thickness dependence of the spatial frequency, and the magnitude of the apparent surface stress increased with the increase of the film thickness. After exposing the aged PMMA-based photoresist at liquid state to gamma-irradiation, the effects of aging and the gamma-irradiation were investigated on the splitting-induced formation of surface structures. For the peeling–splitting process, the differential ratio of the spatial wavelength to the film thickness for the aged samples is larger than that for non-aged samples. The point-load splitting could not produce any surface pattern on the gamma-irradiated films. None of the splitting approaches could form surface structures for polymer films exposed to irradiation of high dose. Both the spatial wavelength and the apparent surface stress increased with the film thickness for the irradiated polymer films. - Highlights: • Using splitting processes, surface ripples were formed on polymer films. • The surface ripples were induced by compressively apparent surface stress. • The spatial wavelength of the ripples is a linear function of the film thickness. • The spatial wavelength of the ripples is affected by gamma-ray irradiation. • The spatial wavelength of the ripples is affected by aging.

Stress and Damage in Polymer Matrix Composite Materials Due to Material Degradation at High Temperatures

Science.gov (United States)

McManus, Hugh L.; Chamis, Christos C.

1996-01-01

This report describes analytical methods for calculating stresses and damage caused by degradation of the matrix constituent in polymer matrix composite materials. Laminate geometry, material properties, and matrix degradation states are specified as functions of position and time. Matrix shrinkage and property changes are modeled as functions of the degradation states. The model is incorporated into an existing composite mechanics computer code. Stresses, strains, and deformations at the laminate, ply, and micro levels are calculated, and from these calculations it is determined if there is failure of any kind. The rationale for the model (based on published experimental work) is presented, its integration into the laminate analysis code is outlined, and example results are given, with comparisons to existing material and structural data. The mechanisms behind the changes in properties and in surface cracking during long-term aging of polyimide matrix composites are clarified. High-temperature-material test methods are also evaluated.

The Research on Polymer Microcapsulation for Cell Technology

Institute of Scientific and Technical Information of China (English)

ZHANG Zhi-bin; LI Min; SONG Hong; FANG Yi; HUA Hui; CHEN Li-guo; ZHOU Wei; WANG Zheng-rong

2004-01-01

Microcapsulation is a technology that enwrapped the solid or liquid or some gas matter with membrane materials to form microparticles(i.e.microcapsules). The materials of microcapsule is composed of naturnal polymers or modified naturnal polymers or synthesized polymers. The water-soluble core matter can only use oil-soluble wall materials, and vice versa.Synthesized methods of polymer microcapsulesSynthesized methods with monomers as raw materialsThis kind of methods include suspension polymerization, emulsion polymerization, dispersal polymerization, precipitation polymerization,suspension condensation polymerization, dispersal condensation polymerization, deposition condensation polymerization, interface condensation polymerization, and so on.Synthesized methods with polymers as raw materialsThese methods are suspension cross-linked polymerization, coacervation phase separation,extraction with solvent evaporation, polymer deposition, polymer chelation, polymer gel,solidification of melting polymer, tray-painted ways, fluidized bed ways, and so forth.Polymer materials to synthesize microcapsules2.1. Naturnal polymer materialsThe characteristics of this kind of materials are easy to form membrane, good stability and no toxicity. The polymer materials include lipids(liposome), amyloses, proteins, plant gels, waxes, etc.2.2. Modified polymer materialsThe characteristics of these materials are little toxicity, high viscidity(viscosity), soluble salt materials. But they cannot be used in water, acidic environment and high temperature environment for a long time. The materials include all kind of derivants of celluloses.2.3. Synthesized polymer materialsThe characteristics of the materials are easy to form membrane, good stability and adjustment of membrane properties. The synthesized polymer materials include degradable polymers(PLA, PGA,PLGA, PCL, PHB, PHV, PHA, PEG, PPG and the like) and indegradable polymers(PA, PMMA,PAM, PS, PVC, PB, PE, PU, PUA, PVA and otherwise

Processing and Material Characterization of Continuous Basalt Fiber Reinforced Ceramic Matrix Composites Using Polymer Derived Ceramics.

Science.gov (United States)

Cox, Sarah B.

2014-01-01

The need for high performance vehicles in the aerospace industry requires materials which can withstand high loads and high temperatures. New developments in launch pads and infrastructure must also be made to handle this intense environment with lightweight, reusable, structural materials. By using more functional materials, better performance can be seen in the launch environment, and launch vehicle designs which have not been previously used can be considered. The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Polymer matrix composites can be used for temperatures up to 260C. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in the composites. In this study, continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. The oxyacetylene torch testing and three point bend testing have been performed on test panels and the test results are presented.

Embrittlement of MISSE 5 Polymers After 13 Months of Space Exposure

Science.gov (United States)

Guo, Aobo; Yi, Grace T.; Ashmead, Claire C.; Mitchell, Gianna G.; deGroh, Kim K.

2012-01-01

Understanding space environment induced degradation of spacecraft materials is essential when designing durable and stable spacecraft components. As a result of space radiation, debris impacts, atomic oxygen interaction, and thermal cycling, the outer surfaces of space materials degrade when exposed to low Earth orbit (LEO). The objective of this study was to measure the embrittlement of 37 thin film polymers after LEO space exposure. The polymers were flown aboard the International Space Station and exposed to the LEO space environment as part of the Materials International Space Station Experiment 5 (MISSE 5). The samples were flown in a nadir-facing position for 13 months and were exposed to thermal cycling along with low doses of atomic oxygen, direct solar radiation and omnidirectional charged particle radiation. The samples were analyzed for space-induced embrittlement using a bend-test procedure in which the strain necessary to induce surface cracking was determined. Bend-testing was conducted using successively smaller mandrels to apply a surface strain to samples placed on a semi-suspended pliable platform. A pristine sample was also tested for each flight sample. Eighteen of the 37 flight samples experienced some degree of surface cracking during bend-testing, while none of the pristine samples experienced any degree of cracking. The results indicate that 49 percent of the MISSE 5 thin film polymers became embrittled in the space environment even though they were exposed to low doses (approx.2.75 krad (Si) dose through 127 mm Kapton) of ionizing radiation.

Colloid electrochemistry of conducting polymer: towards potential-induced in-situ drug release

International Nuclear Information System (INIS)

Sankoh, Supannee; Vagin, Mikhail Yu.; Sekretaryova, Alina N.; Thavarungkul, Panote; Kanatharana, Proespichaya; Mak, Wing Cheung

2017-01-01

Highlights: • Pulsed electrode potential induced an in-situ drug release from dispersion of conducting polymer microcapsules. • Fast detection of the released drug within the colloid microenvironment. • Improved the efficiency of localized drug release at the electrode interface. - Abstract: Over the past decades, controlled drug delivery system remains as one of the most important area in medicine for various diseases. We have developed a new electrochemically controlled drug release system by combining colloid electrochemistry and electro-responsive microcapsules. The pulsed electrode potential modulation led to the appearance of two processes available for the time-resolved registration in colloid microenvironment: change of the electronic charge of microparticles (from 0.5 ms to 0.1 s) followed by the drug release associated with ionic equilibration (1–10 s). The dynamic electrochemical measurements allow the distinction of drug release associated with ionic relaxation and the change of electronic charge of conducting polymer colloid microparticles. The amount of released drug (methylene blue) could be controlled by modulating the applied potential. Our study demonstrated a surface-potential driven controlled drug release of dispersion of conducting polymer carrier at the electrode interfaces, while the bulk colloids dispersion away from the electrode remains as a reservoir to improve the efficiency of localized drug release. The developed new methodology creates a model platform for the investigations of surface potential-induced in-situ electrochemical drug release mechanism.

Silk fibroin as an organic polymer for controlled drug delivery

NARCIS (Netherlands)

Hofmann, S.; Foo, S.; Rossetti, F.; Textor, M.; Vunjak-Novakovic, G.; Kaplan, D.L.; Merkle, H.P.; Meinel, L.

2006-01-01

The pharmaceutical utility of silk fibroin (SF) materials for drug delivery was investigated. SF films were prepared from aqueous solutions of the fibroin protein polymer and crystallinity was induced and controlled by methanol treatment. Dextrans of different molecular weights, as well as proteins,

A micromotor based on polymer single crystals and nanoparticles: toward functional versatility

Science.gov (United States)

Liu, Mei; Liu, Limei; Gao, Wenlong; Su, Miaoda; Ge, Ya; Shi, Lili; Zhang, Hui; Dong, Bin; Li, Christopher Y.

2014-07-01

We report a multifunctional micromotor fabricated by the self-assembly technique using multifunctional materials, i.e. polymer single crystals and nanoparticles, as basic building blocks. Not only can this micromotor achieve autonomous and directed movement, it also possesses unprecedented functions, including enzymatic degradation-induced micromotor disassembly, sustained release and molecular detection.We report a multifunctional micromotor fabricated by the self-assembly technique using multifunctional materials, i.e. polymer single crystals and nanoparticles, as basic building blocks. Not only can this micromotor achieve autonomous and directed movement, it also possesses unprecedented functions, including enzymatic degradation-induced micromotor disassembly, sustained release and molecular detection. Electronic supplementary information (ESI) available: Experimental section, Fig. S1-S8 and Video S1-S4. See DOI: 10.1039/c4nr02593h

Simulation of Stimuli-Responsive Polymer Networks

Directory of Open Access Journals (Sweden)

Thomas Gruhn

2013-11-01

Full Text Available The structure and material properties of polymer networks can depend sensitively on changes in the environment. There is a great deal of progress in the development of stimuli-responsive hydrogels for applications like sensors, self-repairing materials or actuators. Biocompatible, smart hydrogels can be used for applications, such as controlled drug delivery and release, or for artificial muscles. Numerical studies have been performed on different length scales and levels of details. Macroscopic theories that describe the network systems with the help of continuous fields are suited to study effects like the stimuli-induced deformation of hydrogels on large scales. In this article, we discuss various macroscopic approaches and describe, in more detail, our phase field model, which allows the calculation of the hydrogel dynamics with the help of a free energy that considers physical and chemical impacts. On a mesoscopic level, polymer systems can be modeled with the help of the self-consistent field theory, which includes the interactions, connectivity, and the entropy of the polymer chains, and does not depend on constitutive equations. We present our recent extension of the method that allows the study of the formation of nano domains in reversibly crosslinked block copolymer networks. Molecular simulations of polymer networks allow the investigation of the behavior of specific systems on a microscopic scale. As an example for microscopic modeling of stimuli sensitive polymer networks, we present our Monte Carlo simulations of a filament network system with crosslinkers.

Electron beam effects on gelatin polymer

Energy Technology Data Exchange (ETDEWEB)

Inamura, Patricia Y.; Shimazaki, Kleber; Souza, Clecia de M.; Moura, Esperidiana A.B.; Mastro, Nelida L. del, E-mail: patyoko@yahoo.co [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Colombo, Maria A., E-mail: mascolombo@yahoo.com.b [Faculdade de Tecnologia da Zona Leste, Sao Paulo, SP (Brazil)

2009-07-01

The main field of electron-beam radiation processing applications is the modification of polymeric material. Polymer development includes new pathways to produce natural polymers with better mechanical and barrier properties and thermal stability. The aim of this paper was to investigate the behavior of a gelatin/acrylamide polymer treated by electron-beam radiation. Gelatin is a heterogeneous mixture of water-soluble proteins of high average molecular mass derived by hydrolytic action from animal collagen, a fibrous insoluble protein, which is widely found in nature as the major constituent of skin, bones and connective tissue. Hydrolyzed collagen is composed of a unique sequence of amino acids, characterized particularly by the high content of glycine, proline and hydroxyproline. Among biomaterials, gelatin is an interesting material because is a partially crystalline polymer and has a relatively low melting point. Samples of gelatin together with glycerin as plasticizer and acrylamide as copolymer were irradiated with doses of 10 kGy and 40 kGy, using an electron beam accelerator, dose rate 22.41kGy/s, at room temperature in presence of air. After irradiation, some preliminary analyses were done like viscometry, texture analyses and colorimetry. The results of the diverse tests showed changes that can be ascribed to radiation-induced crosslinking. The electron-beam processed acrylamide-gelatin polymer using glycerin as plasticizer must be first extensively characterized before to be used for general applications. (author)

Electron beam effects on gelatin polymer

International Nuclear Information System (INIS)

Inamura, Patricia Y.; Shimazaki, Kleber; Souza, Clecia de M.; Moura, Esperidiana A.B.; Mastro, Nelida L. del; Colombo, Maria A.

2009-01-01

The main field of electron-beam radiation processing applications is the modification of polymeric material. Polymer development includes new pathways to produce natural polymers with better mechanical and barrier properties and thermal stability. The aim of this paper was to investigate the behavior of a gelatin/acrylamide polymer treated by electron-beam radiation. Gelatin is a heterogeneous mixture of water-soluble proteins of high average molecular mass derived by hydrolytic action from animal collagen, a fibrous insoluble protein, which is widely found in nature as the major constituent of skin, bones and connective tissue. Hydrolyzed collagen is composed of a unique sequence of amino acids, characterized particularly by the high content of glycine, proline and hydroxyproline. Among biomaterials, gelatin is an interesting material because is a partially crystalline polymer and has a relatively low melting point. Samples of gelatin together with glycerin as plasticizer and acrylamide as copolymer were irradiated with doses of 10 kGy and 40 kGy, using an electron beam accelerator, dose rate 22.41kGy/s, at room temperature in presence of air. After irradiation, some preliminary analyses were done like viscometry, texture analyses and colorimetry. The results of the diverse tests showed changes that can be ascribed to radiation-induced crosslinking. The electron-beam processed acrylamide-gelatin polymer using glycerin as plasticizer must be first extensively characterized before to be used for general applications. (author)

Effect of dose on radiation-induced conductivity in polymers

International Nuclear Information System (INIS)

Tyutnev, A.P.; Saenko, V.S.; Pozhidaev, E.D.; Ikhsanov, R.Sh.

2007-01-01

Numerical simulation of radiation-induced conductivity in polymers upon long-term irradiation on the basis of the generalized Rose-Fowler-Vaisberg model, which allows for both dipolar carrier transport and generation of radiation traps during irradiation, was performed. The unusual properties of radiation-induced conductivity, such as the appearance of a maximum on current transients, the absence of a steady state, and a substantial difference between these curves for the first and subsequent irradiation, are rationalized in terms of the formation of free radicals, the major feature of radiolysis in the chemical aspect. This interpretation does not require the involvement of degradation or crosslinking processes, unlike other interpretations that appear in the literature. With the use of low-density polyethylene as an example, it was shown that radiation-induced conductivity both upon pulse and continuous irradiation can satisfactorily be described with the unified set of parameters of the generalized Rose-Fowler-Vaisberg model [ru

Optical radiative properties of ablating polymers exposed to high-power arc plasmas

Science.gov (United States)

Becerra, Marley; Pettersson, Jonas

2018-03-01

The radiative properties of polymers exposed to high-intensity radiation are of importance for the numerical simulation of arc-induced ablation. The paper investigates the optical properties of polymethylmethacrylate PMMA and polyamide PA6 films exposed to high-power arc plasmas, which can cause ablation of the material. A four-flux radiative approximation is first used to estimate absorption and scattering coefficients of the tested materials in the ultraviolet (UV) and in the visible (VIS) ranges from spectrophotometric measurements. The temperature-induced variation of the collimated transmissivity of the polymers is also measured from room temperature to the glass temperature of PMMA and the melting temperature of PA6. Furthermore, band-averaged absorption and scattering coefficients of non-ablating and ablating polymers are estimated from the UV to the short-wavelength infrared (SWIR), covering the range of interest for the simulation of arc-induced ablation. These estimates are obtained from collimated transmissivities measured with an additional in situ photometric system that uses a high-power, transient arc plasma to both illuminate the samples and to induce ablation. It is shown that the increase in the bulk temperature of PA6 leads to a strong reversible increase in collimated transmissivity, significantly reducing the absorption and scattering coefficients of the material. A weaker but opposite effect of temperature on the optical properties is found in PMMA. As a consequence, it is suggested that the absorption coefficient of polymers used for arc-induced ablation estimates should not be taken directly from direct collimated transmissivity measurements at room temperature. The band-averaged radiation measurements also show that the layer of products released by ablation of PMMA produces scattering radiation losses mainly in the VIS-SWIR ranges, which are only a small fraction of the total incident arc radiation. In a similar manner, the ablation layer

Sequestering carbon dioxide in industrial polymers: Building materials for the 21st century

Energy Technology Data Exchange (ETDEWEB)

Molton, P.M.; Nelson, D.A.

1993-06-01

This study was undertaken to determine the possibility of developing beneficial uses for carbon dioxide as a key component for a large-volume building product. Such a use may provide an alternative to storing the gas in oceanic sinks or clathrates as a way to slow the rate of global warming. The authors investigated the concept that carbon dioxide might be used with other chemicals to make carbon-dioxide-based polymers which would be lightweight, strong, and economical alternatives to some types of wood and silica-based building materials. As a construction-grade material, carbon dioxide would be fixed in a solid, useful form where it would not contribute to global warming. With the probable imposition of a fuel carbon tax in industrialized countries, this alternative would allow beneficial use of the carbon dioxide and could remove it from the tax basis if legislation were structured appropriately. Hence, there would be an economic driver towards the use of carbon-dioxide-based polymers which would enhance their future applications. Information was obtained through literature searches and personal contacts on carbon dioxide polymers which showed that the concept (1) is technically feasible, (2) is economically defensible, and (3) has an existing industrial infrastructure which could logically develop it. The technology exists for production of building materials which are strong enough for use by industry and which contain up to 90% by weight of carbon dioxide, both chemically and physically bound. A significant side-benefit of using this material would be that it is self-extinguishing in case of fire. This report is the first stage in the investigation. Further work being proposed will provide details on costs, specific applications and volumes, and potential impacts of this technology.

An aqueous, polymer-based redox-flow battery using non-corrosive, safe, and low-cost materials

Science.gov (United States)

Janoschka, Tobias; Martin, Norbert; Martin, Udo; Friebe, Christian; Morgenstern, Sabine; Hiller, Hannes; Hager, Martin D.; Schubert, Ulrich S.

2015-11-01

For renewable energy sources such as solar, wind, and hydroelectric to be effectively used in the grid of the future, flexible and scalable energy-storage solutions are necessary to mitigate output fluctuations. Redox-flow batteries (RFBs) were first built in the 1940s and are considered a promising large-scale energy-storage technology. A limited number of redox-active materials--mainly metal salts, corrosive halogens, and low-molar-mass organic compounds--have been investigated as active materials, and only a few membrane materials, such as Nafion, have been considered for RFBs. However, for systems that are intended for both domestic and large-scale use, safety and cost must be taken into account as well as energy density and capacity, particularly regarding long-term access to metal resources, which places limits on the lithium-ion-based and vanadium-based RFB development. Here we describe an affordable, safe, and scalable battery system, which uses organic polymers as the charge-storage material in combination with inexpensive dialysis membranes, which separate the anode and the cathode by the retention of the non-metallic, active (macro-molecular) species, and an aqueous sodium chloride solution as the electrolyte. This water- and polymer-based RFB has an energy density of 10 watt hours per litre, current densities of up to 100 milliamperes per square centimetre, and stable long-term cycling capability. The polymer-based RFB we present uses an environmentally benign sodium chloride solution and cheap, commercially available filter membranes instead of highly corrosive acid electrolytes and expensive membrane materials.

An aqueous, polymer-based redox-flow battery using non-corrosive, safe, and low-cost materials.

Science.gov (United States)

Janoschka, Tobias; Martin, Norbert; Martin, Udo; Friebe, Christian; Morgenstern, Sabine; Hiller, Hannes; Hager, Martin D; Schubert, Ulrich S

2015-11-05

For renewable energy sources such as solar, wind, and hydroelectric to be effectively used in the grid of the future, flexible and scalable energy-storage solutions are necessary to mitigate output fluctuations. Redox-flow batteries (RFBs) were first built in the 1940s and are considered a promising large-scale energy-storage technology. A limited number of redox-active materials--mainly metal salts, corrosive halogens, and low-molar-mass organic compounds--have been investigated as active materials, and only a few membrane materials, such as Nafion, have been considered for RFBs. However, for systems that are intended for both domestic and large-scale use, safety and cost must be taken into account as well as energy density and capacity, particularly regarding long-term access to metal resources, which places limits on the lithium-ion-based and vanadium-based RFB development. Here we describe an affordable, safe, and scalable battery system, which uses organic polymers as the charge-storage material in combination with inexpensive dialysis membranes, which separate the anode and the cathode by the retention of the non-metallic, active (macro-molecular) species, and an aqueous sodium chloride solution as the electrolyte. This water- and polymer-based RFB has an energy density of 10 watt hours per litre, current densities of up to 100 milliamperes per square centimetre, and stable long-term cycling capability. The polymer-based RFB we present uses an environmentally benign sodium chloride solution and cheap, commercially available filter membranes instead of highly corrosive acid electrolytes and expensive membrane materials.

Polymer architecture and drug delivery.

Science.gov (United States)

Qiu, Li Yan; Bae, You Han

2006-01-01

Polymers occupy a major portion of materials used for controlled release formulations and drug-targeting systems because this class of materials presents seemingly endless diversity in topology and chemistry. This is a crucial advantage over other classes of materials to meet the ever-increasing requirements of new designs of drug delivery formulations. The polymer architecture (topology) describes the shape of a single polymer molecule. Every natural, seminatural, and synthetic polymer falls into one of categorized architectures: linear, graft, branched, cross-linked, block, star-shaped, and dendron/dendrimer topology. Although this topic spans a truly broad area in polymer science, this review introduces polymer architectures along with brief synthetic approaches for pharmaceutical scientists who are not familiar with polymer science, summarizes the characteristic properties of each architecture useful for drug delivery applications, and covers recent advances in drug delivery relevant to polymer architecture.

Amphiphilic invertible polymers: Self-assembly into functional materials driven by environment polarity

Science.gov (United States)

Hevus, Ivan

Stimuli-responsive polymers adapt to environmental changes by adjusting their chain conformation in a fast and reversible way. Responsive polymeric materials have already found use in electronics, coatings industry, personal care, and bio-related areas. The current work aims at the development of novel responsive functional polymeric materials by manipulating environment-dependent self-assembly of a new class of responsive macromolecules strategically designed in this study,—amphiphilic invertible polymers (AIPs). Environment-dependent micellization and self-assembly of three different synthesized AIP types based on poly(ethylene glycol) as a hydrophilic fragment and varying hydrophobic constituents was demonstrated in polar and nonpolar solvents, as well as on the surfaces and interfaces. With increasing concentration, AIP micelles self-assemble into invertible micellar assemblies composed of hydrophilic and hydrophobic domains. Polarity-responsive properties of AIPs make invertible micellar assemblies functional in polar and nonpolar media including at interfaces. Thus, invertible micellar assemblies solubilize poorly soluble substances in their interior in polar and nonpolar solvents. In a polar aqueous medium, a novel stimuli-responsive mechanism of drug release based on response of AIP-based drug delivery system to polarity change upon contact with the target cell has been established using invertible micellar assemblies loaded with curcumin, a phytochemical drug. In a nonpolar medium, invertible micellar assemblies were applied simultaneously as nanoreactors and stabilizers for size-controlled synthesis of silver nanoparticles stable in both polar and nonpolar media. The developed amphiphilic nanosilver was subsequently used as seeds to promote anisotropic growth of CdSe semiconductor nanoparticles that have potential in different applications ranging from physics to medicine. Amphiphilic invertible polymers were shown to adsorb on the surface of silica

A Comparison of Water Diffusion in Polymer Based Fuel Cell and Reverse Osmosis Membrane Materials

Science.gov (United States)

Soles, Christopher; Frieberg, Bradley; Tarver, Jacob; Tyagi, Madhusudan; Jeong, Cheol; Chan, Edwin; Stafford, Christopher

Hydrated polymer membranes are critical in both fuel cells and water filtration and desalination. In both of these applications the membrane function (selectively transporting or separating ions) is coupled with the transport of water through the membrane. There is a significant need to understand the nature by which the water and ions distribute and move through these membranes. This presentation compares the transport mechanisms in in an ion containing block copolymer alkaline fuel cell membrane with that of a polyamide membrane that is used as the active layer in a reverse osmosis water desalination membrane. Small angle neutron scattering measurements are used to locally probe how water swells the different materials and quantitatively describe the distribution of water within the membrane microstructures. Quasielastic neutron scattering measurements are then used to separate the polymer dynamics of the host membranes from the dynamics of the water inside the membranes. This reveals that water moves at least an order of magnitude slower through the ion containing fuel cell membrane materials, consistent with a solution-diffusion model, while the water in the polyamide membranes moves faster, consistent with a pore-flow diffusion mechanism. These insights will be discussed in terms of a coupling of the water and polymer dynamics and design cues for high performance membrane materials.

Opposite photo-induced deformations in azobenzene-containing polymers with different molecular architecture: Molecular dynamics study

International Nuclear Information System (INIS)

Ilnytskyi, Jaroslav M.; Neher, Dieter; Saphiannikova, Marina

2011-01-01

Photo-induced deformations in azobenzene-containing polymers (azo-polymers) are central to a number of applications, such as optical storage and fabrication of diffractive elements. The microscopic nature of the underlying opto-mechanical coupling is yet not clear. In this study, we address the experimental finding that the scenario of the effects depends on molecular architecture of the used azo-polymer. Typically, opposite deformations in respect to the direction of light polarization are observed for liquid crystalline and amorphous azo-polymers. In this study, we undertake molecular dynamics simulations of two different models that mimic these two types of azo-polymers. We employ hybrid force field modeling and consider only trans-isomers of azobenzene, represented as Gay-Berne sites. The effect of illumination on the orientation of the chromophores is considered on the level of orientational hole burning and emphasis is given to the resulting deformation of the polymer matrix. We reproduce deformations of opposite sign for the two models being considered here and discuss the relevant microscopic mechanisms in both cases.

Fabrication of polymer-alloy based on polytetrafluoroethylene by radiation-crosslinking

International Nuclear Information System (INIS)

Oshima, A.; Asano, S.; Hyunga, T.; Ichizuri, S.; Washio, M.

2003-01-01

Perfluoropolymer such as polytetrafluoroethylene (PTFE), tetrafluoroethylene co-perfluoroalkylvinylether (PFA) and tetrafluoroethylene-co-hexafluoropropylene (FFP) have been classified to be a typical polymer of radiation-induced degradation. However, we confirmed that the crosslinking of PTFE, PFA and FEP proceed by irradiation under selective condition where oxygen-free and high temperature above the melting temperature of them. In this study, fabrication of polymer-alloy based on PTFE has been demonstrated by radiation-crosslinking techniques. The polymer alloy, which was PTFE fine powder contained with other polymeric materials, was obtained by electron beams irradiation under oxygen-free atmosphere. Characterization of polymer-alloy based on PTFE has been studied by various measurements such as solid state 19F- and 13C-NMR spectroscopy, thermal analysis (DSC, TGA)

Stimuli-Adaptable Materials

DEFF Research Database (Denmark)

Frankær, Sarah Maria Grundahl

The work presented in this Thesis deals with the development of a stimuli-adaptable polymer material based on the UV-induced dimerisation of cinnamic acid and its derivatives. It is in the nature of an adhesive to adhere very well to its substrate and therefore problems can arise upon removal...

Ferroelectric polymer dielectrics: Emerging materials for future electrostatic energy storage applications

Science.gov (United States)

Panda, Maheswar

2018-05-01

In this manuscript, the dielectric behavior of a variety of ferroelectric polymer dielectrics (FPD), which may bethe materials for future electrostatic energy storage application shave been discussed. The variety of polymer dielectrics, comprising of ferroelectric polymer[polyvinylidene fluoride (PVDF)]/non-polarpolymer [low density polyethylene (LDPE)] and different sizes of metal particles (Ni, quasicrystal of Al-Cu-Fe) as filler, were prepared through different process conditions (cold press/hot press) and are investigated experimentally. Very high values of effective dielectric constants (ɛeff) with low loss tangent (Tan δ) were observed forall the prepared FPD at their respective percolation thresholds (fc). The enhancement of ɛeff and Tan δ at the insulator to metal transition (IMT) is explained through the boundary layer capacitor effect and the percolation theory respectively. The non-universal fc/critical exponents across the IMT have been explained through percolation theory andis attributed to the fillerparticle size& shape, interaction between the components, method of their preparation, adhesiveness, connectivity and homogeneity, etc. of the samples. Recent results on developed FPD with high ɛeff and low Tan δ prepared through cold press have proven themselves to be the better candidates for low frequency and static dielectric applications.

Motion of Adsorbed Nano-Particles on Azobenzene Containing Polymer Films

Directory of Open Access Journals (Sweden)

Sarah Loebner

2016-12-01

Full Text Available We demonstrate in situ recorded motion of nano-objects adsorbed on a photosensitive polymer film. The motion is induced by a mass transport of the underlying photoresponsive polymer material occurring during irradiation with interference pattern. The polymer film contains azobenzene molecules that undergo reversible photoisomerization reaction from trans- to cis-conformation. Through a multi-scale chain of physico-chemical processes, this finally results in the macro-deformations of the film due to the changing elastic properties of polymer. The topographical deformation of the polymer surface is sensitive to a local distribution of the electrical field vector that allows for the generation of dynamic changes in the surface topography during irradiation with different light interference patterns. Polymer film deformation together with the motion of the adsorbed nano-particles are recorded using a homemade set-up combining an optical part for the generation of interference patterns and an atomic force microscope for acquiring the surface deformation. The particles undergo either translational or rotational motion. The direction of particle motion is towards the topography minima and opposite to the mass transport within the polymer film. The ability to relocate particles by photo-induced dynamic topography fluctuation offers a way for a non-contact simultaneous manipulation of a large number of adsorbed particles just in air at ambient conditions.

Material Evaluation and Process Optimization of CNT-Coated Polymer Powders for Selective Laser Sintering

Directory of Open Access Journals (Sweden)

Shangqin Yuan

2016-10-01

Full Text Available Multi-walled carbon nanotubes (CNTs as nano-reinforcements were introduced to facilitate the laser sintering process and enhance the thermal and mechanical properties of polymeric composites. A dual experimental-theoretical method was proposed to evaluate the processability and predict the process parameters of newly developed CNT-coated polyamide 12 (CNTs/PA12 powders. The thermal conductivity, melt viscosity, phase transition and temperature-dependent density and heat capacity of PA12 and CNTs/PA12 powders were characterized for material evaluation. The composite powders exhibited improved heat conduction and heat absorption compared with virgin polymer powders, and the stable sintering range of composite powders was extended and found to be favourable for the sintering process. The microstructures of sintered composites revealed that the CNTs remained at the powder boundaries and formed network architectures, which instantaneously induced the significant enhancements in tensile strength, elongation at break and toughness without sacrificing tensile modulus.

Durable polymer-aerogel based superhydrophobic coatings, a composite material

Science.gov (United States)

Kissel, David J; Brinker, Charles Jeffrey

2014-03-04

Provided are polymer-aerogel composite coatings, devices and articles including polymer-aerogel composite coatings, and methods for preparing the polymer-aerogel composite. The exemplary article can include a surface, wherein the surface includes at least one region and a polymer-aerogel composite coating disposed over the at least one region, wherein the polymer-aerogel composite coating has a water contact angle of at least about 140.degree. and a contact angle hysteresis of less than about 1.degree.. The polymer-aerogel composite coating can include a polymer and an ultra high water content catalyzed polysilicate aerogel, the polysilicate aerogel including a three dimensional network of silica particles having surface functional groups derivatized with a silylating agent and a plurality of pores.

Durable polymer-aerogel based superhydrophobic coatings: a composite material

Science.gov (United States)

Kissel, David J.; Brinker, Charles Jeffrey

2016-02-02

Provided are polymer-aerogel composite coatings, devices and articles including polymer-aerogel composite coatings, and methods for preparing the polymer-aerogel composite. The exemplary article can include a surface, wherein the surface includes at least one region and a polymer-aerogel composite coating disposed over the at least one region, wherein the polymer-aerogel composite coating has a water contact angle of at least about 140.degree. and a contact angle hysteresis of less than about 1.degree.. The polymer-aerogel composite coating can include a polymer and an ultra high water content catalyzed polysilicate aerogel, the polysilicate aerogel including a three dimensional network of silica particles having surface functional groups derivatized with a silylating agent and a plurality of pores.

New infrared transmitting material via inverse vulcanization of elemental sulfur to prepare high refractive index polymers.

Science.gov (United States)

Griebel, Jared J; Namnabat, Soha; Kim, Eui Tae; Himmelhuber, Roland; Moronta, Dominic H; Chung, Woo Jin; Simmonds, Adam G; Kim, Kyung-Jo; van der Laan, John; Nguyen, Ngoc A; Dereniak, Eustace L; Mackay, Michael E; Char, Kookheon; Glass, Richard S; Norwood, Robert A; Pyun, Jeffrey

2014-05-21

Polymers for IR imaging: The preparation of high refractive index polymers (n = 1.75 to 1.86) via the inverse vulcanization of elemental sulfur is reported. High quality imaging in the near (1.5 μm) and mid-IR (3-5 μm) regions using high refractive index polymeric lenses from these sulfur materials was demonstrated. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Photon-induced formation of CdS nanocrystals in selected areas of polymer matrices

International Nuclear Information System (INIS)

Athanassiou, Athanassia; Cingolani, Roberto; Tsiranidou, Elsa; Fotakis, Costas; Laera, Anna Maria; Piscopiello, Emanuela; Tapfer, Leander

2007-01-01

We demonstrate light-induced formation of semiconductor quantum dots in TOPAS registered polymer matrix with very high control of their size and their spatial localization. Irradiation with UV laser pulses of polymer films embedding Cd thiolate precursors results in the formation of cadmium sulfide nanocrystals well confined in the irradiation area, through a macroscopically nondestructive procedure for the host matrix. With increasing number of laser pulses, we accomplish the formation of nanoparticles with gradually increasing dimensions, resulting in the dynamic change of the spectra emitted by the formed nanocomposite areas. The findings are supported by x-ray diffraction and transmission electron microscopy measurements

Sustainability of silver nanoparticles in solutions and polymer materials

International Nuclear Information System (INIS)

Khaydarov, R.R.; Malikov, Sh.; Khaydarov, R.A.; Mironov, V.V.

2006-01-01

The technology of obtaining stable silver nanoparticles in solutions and composite materials for attainment of antimicrobial and antifungal properties to different surfaces has been developed. The shape of particles is spherical, diameter is about 5 nm. Various concentrations of silver nanoparticles have been deposited onto surfaces of different materials (cotton and synthetic fabrics, fibroid sorbents and polymer materials). Different ways of treatment and densities of nanoparticles on the treated surface have been studied during 6 months with respect to the best sustainability. In order to prevent agglomeration of obtained metal nanoparticles on the surface of materials treated, stabilizing reagents (ethylene glycol, formic acid, sodium dodecyl sulphate, etc.) have been used and their relative efficacy has been examined. Residual concentrations of the nanoparticles on various fabrics after 1, 3, 5 and 10 cycles of washing have been also studied. The treated fabrics keep their antibacterial properties after at least 3 times of laundering. The best finishing process to attach silver nanoparticles combination to various materials has been compared with biocidal properties of such antibacterial agents as metal salt solutions and zinc pyrithione.The possibility of treatment of nuclear track membranes by silver nanoparticles in order to prevent microbial growth on the surface of membranes has been discussed. (author)

Interphase and particle dispersion correlations in polymer nanocomposites

Science.gov (United States)

Senses, Erkan

for polymers on attractive particle surfaces. The shown thermally-induced stiffening behavior is reversible and makes this interfacial mechanism highly attractive in developing new active, remotely controllable engineered materials from non-responsive components.

PEG encapsulated by porous triamide-linked polymers as support for solid-liquid phase change materials for energy storage

Science.gov (United States)

Andriamitantsoa, Radoelizo S.; Dong, Wenjun; Gao, Hongyi; Wang, Ge

2017-03-01

A series of porous triamide-linked polymers labeled as PTP were prepared by condensation of 1,3,5-benzenetricarbonyl trichloride with benzene-1,4-diamine (A), 4,4‧-methylenediamine (B) and 1,3,5-triazine-2,4,6-triamine (C) respectively. The as-synthesized polymers exhibit permanent porosity and high surface areas which guarantee to hold polyethylene glycol (PEG) molecules in their network for shape-stabilized phase change materials. They possess different effects on the phase change properties of the composite due to their different porosities. PTP-A have intrinsic well-ordered morphology, microstructure and good enough pores to keep the PCMs compared to PTP-B and PTP-C. PEG 2000 used as PCMs could be retained up to 85 wt% in PTP-A polymer materials and these composites were defined as form-stable composite PCMs without the leakage of melted PCM. The thermal study revealed a good storage effect of encapsulated polymer and the enthalpy of melting increases in the order PTP-C PCMs.

Photomobile polymer materials towards eight driven plastic motors

International Nuclear Information System (INIS)

Tomi Ikeda

2007-01-01

We present the first report of working photomechanical devices, and simple plastic motors, driven only by light. The size scale of the energy transduction systems here is mm for demonstration, but is not principle material-limited, so numerous applications on the nano-scale are possible where efficient power supply to mechanical systems is battery-free and non-contact. The photomobile polymers function with a minimum of moving parts which minimizes the friction and surface contact difficulties on the small scale, and one can further envisage applications as direct solar-to-mechanical energy conversion and storage systems, and use in devices requiring through-space power transmission such as microfluidic device control, bio-interfaces, or other remote power supply. (Author)

Effects of ion beam treatment on atomic and macroscopic adhesion of copper to different polymer materials

International Nuclear Information System (INIS)

Zaporojtchenko, V.; Zekonyte, J.; Faupel, F.

2007-01-01

Low-energy ion irradiation of polymer induces different phenomena in the near surface layer, which effect strongly the metal-polymer interface formation and promotes adhesion of polymers to metals. Low-energy argon and oxygen ion beams were used to alter the chemical and physical properties of different polymers (PS (polystyrene), PαMS (poly(α-methylstyrene), BPA-PC (bisphenol-A-polycarbonate) and PMMA (poly(methyl methacrylate)), in order to understand the adhesion phenomena between a deposited Cu layer and the polymers. The resulting changes were investigated by various techniques including X-ray photoelectron spectroscopy, measurements of the metal condensation coefficient and a new technique to measure cross-linking at the polymer surface. Two types of practical adhesion strengths of Cu-polymer systems, measured using 90 o peel tests, were observed: (i) peel strength increased at low ion fluences, reached a maximum and then decreased after prolonged treatment and (ii) no improvement in the peel strength on treated polymer surfaces was recorded. The improvement in the metal-polymer adhesion in the ion fluence range of 10 13 -10 15 cm -2 is attributed to the creation of a large density of new adsorption sites resulting in a larger contact area and incorporation of chemically active groups that lead to increased interaction between metal and polymer by metal-oxygen-polymer species formation. XPS analysis of peeled-off surfaces showed that in most cases the failure location changed from interfacial for untreated polymers to cohesive failure in the polymer for treated surfaces. These observations and measurements of the metal condensation coefficients suggest that bonding is improved at the metal-polymer interface for all metal-polymer systems. However, the decrease in the peel strength at high ion fluences is attributed to the formation of a weak boundary layer in polymers. The correlation between sputter rate of polymers and altering in the peel strength for

Development of Polymer Acceptors for Organic Photovoltaic Cells

Directory of Open Access Journals (Sweden)

Yujeong Kim

2014-02-01

Full Text Available This review provides a current status report of the various n-type polymer acceptors for use as active materials in organic photovoltaic cells (OPVs. The polymer acceptors are divided into four categories. The first section of this review focuses on rylene diimide-based polymers, including perylene diimide, naphthalene diimide, and dithienocoronene diimide-based polymers. The high electron mobility and good stability of rylene diimides make them suitable for use as polymer acceptors in OPVs. The second section deals with fluorene and benzothiadiazole-based polymers such as poly(9,9’-dioctylfluorene-co-benzothiadiazole, and the ensuing section focuses on the cyano-substituted polymer acceptors. Cyano-poly(phenylenevinylene and poly(3-cyano-4-hexylthiophene have been used as acceptors in OPVs and exhibit high electron affinity arising from the electron-withdrawing cyano groups in the vinylene group of poly(phenylenevinylene or the thiophene ring of polythiophene. Lastly, a number of other electron-deficient groups such as thiazole, diketopyrrolopyrrole, and oxadiazole have also been introduced onto polymer backbones to induce n-type characteristics in the polymer. Since the first report on all-polymer solar cells in 1995, the best power conversion efficiency obtained with these devices to date has been 3.45%. The overall trend in the development of n-type polymer acceptors is presented in this review.

Composite materials obtained by the ion-plasma sputtering of metal compound coatings on polymer films

Science.gov (United States)

Khlebnikov, Nikolai; Polyakov, Evgenii; Borisov, Sergei; Barashev, Nikolai; Biramov, Emir; Maltceva, Anastasia; Vereshchagin, Artem; Khartov, Stas; Voronin, Anton

2016-01-01

In this article, the principle and examples composite materials obtained by deposition of metal compound coatings on polymer film substrates by the ion-plasma sputtering method are presented. A synergistic effect is to obtain the materials with structural properties of the polymer substrate and the surface properties of the metal deposited coatings. The technology of sputtering of TiN coatings of various thicknesses on polyethylene terephthalate films is discussed. The obtained composites are characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and scanning tunneling microscopy (STM) is shown. The examples of application of this method, such as receiving nanocomposite track membranes and flexible transparent electrodes, are considered.

Conjugated Polymers for Energy Production

DEFF Research Database (Denmark)

Livi, Francesco

This dissertation is aimed at developing materials for flexible, large area, ITO-free polymer solar cells (PSCs) fully printed under ambient conditions. A large screening of conjugated polymers, both novel and well-known materials, has been carried out in order to find suitable candidates...... polymerization method for industrial production of polymers. Several DArP protocols have been employed for the synthesis of PPDTBT leading to polymers with high structural regularity and photovoltaic performances comparable with the same materials synthesized via Stille cross-coupling polymerization...

Thermo-cleavable polymers: Materials with enhanced photochemical stability

DEFF Research Database (Denmark)

Manceau, Matthieu; Petersen, Martin Helgesen; Krebs, Frederik C

2010-01-01

Photochemical stability of three thermo-cleavable polymers was investigated as thin films under atmospheric conditions. A significant increase in lifetime was observed once the side-chain was cleaved emphasizing the detrimental effect of solubilizing groups on the photochemical stability of conju......Photochemical stability of three thermo-cleavable polymers was investigated as thin films under atmospheric conditions. A significant increase in lifetime was observed once the side-chain was cleaved emphasizing the detrimental effect of solubilizing groups on the photochemical stability...... of conjugated polymers. In addition to their ease of processing, thermo-cleavable polymers thus also offer a greater intrinsic stability under illumination....

Realization and characterization of a cellulose and conducting polymer-based ultrathin films composite material

International Nuclear Information System (INIS)

Henry, Christelle

1998-01-01

This work was dedicated to the realization and the characterization of an organic composite material in order to obtain organized ultrathin films with high conductivity and good mechanical properties. In this purpose, the Langmuir-Blodgett (LB) film of a crosslinked alkyl cellulose (rigid-rod polymer) was used as a host matrix for the electro-polymerization of alkyl thiophene and pyrrole. The first interesting result was the synthesis of a bigger amount of conducting alkyl polymer in the presence of cellulose. With the help of a photo-patterning technique, we were able to form contacts more or less conducting on the substrate. We have also shown that the conducting polymer grows beyond the electrode area until distances never described up to now in the literature. A preferential orientation of the conducting polymer chains along the LB dipping direction of the cellulose has been observed in some cases. Even for the films without molecular orientation, we have systematically observed a microscopic or macroscopic anisotropy. This phenomenon appears as domains concentrated in conducting polymers with anisotropic shapes oriented along the dipping direction. Finally, we have noticed that cellulose doesn't change the conductivity and the electrochromic properties of the conducting polymer. Beyond the keeping of these intrinsic properties, the matrix allows to stabilize the film when it is in contact with an organic solvent. (author) [fr

Low-Cost and Green Fabrication of Polymer Electronic Devices by Push-Coating of the Polymer Active Layers.

Science.gov (United States)

Vohra, Varun; Mróz, Wojciech; Inaba, Shusei; Porzio, William; Giovanella, Umberto; Galeotti, Francesco

2017-08-02

Because of both its easy processability and compatibility with roll-to-roll processes, polymer electronics is considered to be the most promising technology for the future generation of low-cost electronic devices such as light-emitting diodes and solar cells. However, the state-of-the-art deposition technique for polymer electronics (spin-coating) generates a high volume of chlorinated solution wastes during the active layer fabrication. Here, we demonstrate that devices with similar or higher performances can be manufactured using the push-coating technique in which a poly(dimethylsiloxane) (PDMS) layer is simply laid over a very small amount of solution (less than 1μL/covered cm 2 ), which is then left for drying. Using mm thick PDMS provides a means to control the solvent diffusion kinetics (sorption/retention) and removes the necessity for additional applied pressure to generate the desired active layer thickness. Unlike spin-coating, push-coating is a slow drying process that induces a higher degree of crystallinity in the polymer thin film without the necessity for a post-annealing step. The polymer light-emitting diodes and solar cells prepared by push-coating exhibit slightly higher performances with respect to the reference spin-coated devices, whereas at the same time reduce the amounts of active layer materials and chlorinated solvents by 50 and 20 times, respectively. These increased performances can be correlated to the higher polymer crystallinities obtained without applying a post-annealing treatment. As push-coating is a roll-to-roll compatible method, the results presented here open the path to low-cost and eco-friendly fabrication of a wide range of emerging devices based on conjugated polymer materials.

Republic of Korea [Status and technology of polymer-containing fibrous materials in the Eastern Hemisphere

Energy Technology Data Exchange (ETDEWEB)

Sung, Chwa-Kyung [Office of Atomic Energy, Seoul (Korea, Republic of)

1968-10-15

In describing the present status of composite materials made from fibrous materials and synthetic polymers, it should first be mentioned that Korea produces almost no polymer-wood combinations. However, Korea has been very active in the production of various resin-fibrous material combinations that mainly employ thermosetting resins as binding agents to improve the quality of woods and other fibrous materials. Plywood, chip board, hard board and straw board are some examples. Korean forest resources are not sufficient to meet industrial needs. Only a small amount of domestic pine timber is used for ground pulp production. However, plywood production, which started some ten years ago, has increased to where domestic consumption is now fully supplied and annual exports are now worth more than 40 million US dollars. Although whole log timber for the industry is imported, urea and formalin for adhesives are produced domestically. To develop an effective means for using waste lumber, chip board, fibre board and hard board have been produced since 1962 and the production of straw board has been started as a means of utilizing agricultural wastes.

Multifunctional Nanotube Polymer Nanocomposites for Aerospace Applications: Adhesion between SWCNT and Polymer Matrix

Science.gov (United States)

Park, Cheol; Wise, Kristopher E.; Kang, Jin Ho; Kim, Jae-Woo; Sauti, Godfrey; Lowther, Sharon E.; Lillehei, Peter T.; Smith, Michael W.; Siochi, Emilie J.; Harrison, Joycelyn S.;

Preparation of polymer electrolyte membranes for lithium batteries by radiation-induced graft copolymerization

Energy Technology Data Exchange (ETDEWEB)

Nasef, Mohamed Mahmoud [Business and Advanced Technology Centre, Universiti Teknologi Malaysia, Jalan Semarak, 54100 Kuala Lumpur (Malaysia); Suppiah, Raja Rajeswary [Chemical Engineering Program, Universiti Teknologi Petronas, Bandar Seri Iskandar, 37150 Tronoh, Perak (Malaysia); Dahlan, Khairul Zaman Mohd [Malaysian Institute for Nuclear Technology Research, Bangi, 43000 Kajang (Malaysia)

2004-07-30

Polymer electrolyte membranes with different degrees of grafting were prepared by radiation-induced graft copolymerization of styrene monomer onto poly(vinylidene fluoride) (PVDF) films and subsequent chemical activation with liquid electrolyte consisting of lithium hexafluorophosphate (LiPF{sub 6}) in a mixture of ethylene carbonate/diethylene carbonate (EC/DEC). The chemical changes in the PVDF films after styrene grafting and subsequent chemical activation were monitored by FTIR spectroscopic analysis and the crystallinity was evaluated using differential scanning calorimetric (DSC) analysis. The swelling in electrolyte solution (electrolyte uptake) and the ionic conductivity of the membranes were determined at various degrees of grafting. The conductivity of the membranes was found to increase with the increase in the degree of grafting and reached a magnitude of 10{sup -3} S/cm at a degree of grafting of 50%. The results of this work suggest that radiation-induced graft polymerization provides an alternative method to substitute blending in preparation of polymer electrolyte membranes for application in lithium batteries.

Shape-tailored polymer colloids on the road to become structural motifs for hierarchically organized materials.

Science.gov (United States)

Plüisch, Claudia Simone; Wittemann, Alexander

2013-12-01

Anisometric polymer colloids are likely to behave differently when compared with centrosymmetric particles. Their study may not only shine new light on the organization of matter; they may also serve as building units with specific symmetries and complexity to build new materials from them. Polymer colloids of well-defined complex geometries can be obtained by packing a limited number of spherical polymer particles into clusters with defined configurations. Such supracolloidal architectures can be fabricated at larger scales using narrowly dispersed emulsion droplets as templates. Assemblies built from at least two different types of particles as elementary building units open perspectives in selective targeting of colloids with specific properties, aiming for mesoscale building blocks with tailor-made morphologies and multifunctionality. Polymer colloids with defined geometries are also ideal to study shape-dependent properties such as the diffusion of complex particles. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interpenetrating polymer networks from acetylene terminated materials

Science.gov (United States)

Connell, J. W.; Hergenrother, P. M.

1989-01-01

As part of a program to develop high temperature/high performance structural resins for aerospace applications, the chemistry and properties of a novel class of interpenetrating polymer networks (IPNs) were investigated. These IPNs consist of a simple diacetylenic compound (aspartimide) blended with an acetylene terminated arylene ether oligomer. Various compositional blends were prepared and thermally cured to evaluate the effect of crosslink density on resin properties. The cured IPNs exhibited glass transition temperatures ranging from 197 to 254 C depending upon the composition and cure temperature. The solvent resistance, fracture toughness and coefficient of thermal expansion of the cured blends were related to the crosslink density. Isothermal aging of neat resin moldings, adhesive and composite specimens showed a postcure effect which resulted in improved elevated temperature properties. The chemistry, physical and mechanical properties of these materials will be discussed.

Communication: Polarizable polymer chain under external electric field in a dilute polymer solution.

Science.gov (United States)

Budkov, Yu A; Kolesnikov, A L; Kiselev, M G

2015-11-28

We study the conformational behavior of polarizable polymer chain under an external homogeneous electric field within the Flory type self-consistent field theory. We consider the influence of electric field on the polymer coil as well as on the polymer globule. We show that when the polymer chain conformation is a coil, application of external electric field leads to its additional swelling. However, when the polymer conformation is a globule, a sufficiently strong field can induce a globule-coil transition. We show that such "field-induced" globule-coil transition at the sufficiently small monomer polarizabilities goes quite smoothly. On the contrary, when the monomer polarizability exceeds a certain threshold value, the globule-coil transition occurs as a dramatic expansion in the regime of first-order phase transition. The developed theoretical model can be applied to predicting polymer globule density change under external electric field in order to provide more efficient processes of polymer functionalization, such as sorption, dyeing, and chemical modification.

Induced-Fission Imaging of Nuclear Material

International Nuclear Information System (INIS)

Hausladen, Paul; Blackston, Matthew A.; Mullens, James Allen; McConchie, Seth M.; Mihalczo, John T.; Bingham, Philip R.; Ericson, Milton Nance; Fabris, Lorenzo

2010-01-01

This paper presents initial results from development of the induced-fission imaging technique, which can be used for the purpose of measuring or verifying the distribution of fissionable material in an unopened container. The technique is based on stimulating fissions in nuclear material with 14 MeV neutrons from an associated-particle deuterium-tritium (D-T) generator and counting the subsequent induced fast fission neutrons with an array of fast organic scintillation detectors. For each source neutron incident on the container, the neutron creation time and initial trajectory are known from detection of the associated alpha particle of the d + t → α + n reaction. Many induced fissions will lie along (or near) the interrogating neutron path, allowing an image of the spatial distribution of prompt induced fissions, and thereby fissionable material, to be constructed. A variety of induced-fission imaging measurements have been performed at Oak Ridge National Laboratory with a portable, low-dose D-T generator, including single-view radiographic measurements and three-dimensional tomographic measurements. Results from these measurements will be presented along with the neutron transmission images that have been performed simultaneously. This new capability may have applications to a number of areas in which there may be a need to confirm the presence or configuration of nuclear materials, such as nuclear material control and accountability, quality assurance, treaty confirmation, or homeland security applications.

Development of Polymer Blends in order to Toughening of Polymers: A review

Directory of Open Access Journals (Sweden)

Carlos Bruno Barreto Luna

2015-05-01

Full Text Available Polymers are materials of large use in the various sectors of the world economy. The use of polymeric materials in daily life, instead of the classic materials has increased in recent decades. However, for certain structural applications polymers need to get tougher. One of the principal toughening techniques based on physical mixture of two or more components, forming the so-called polymer blends. The addition of rubber or not vulcanized in polymer compositions is reported in the literature as a means of generating mixtures of easy processing, and economically advantageous to increase the toughness of the thermoplastic matrix of interest. Moreover, it can be an alternative for the recycling of waste tires and footwear coming from industries, as well reduce harmful effects on the environment. Therefore, the present study aims to present a review of the definitions, benefits, thermodynamic fundamentals and toughening polymers.

Biocompatibility of polymer-infiltrated-ceramic-network (PICN) materials with Human Gingival Fibroblasts (HGFs).

Science.gov (United States)

Grenade, Charlotte; De Pauw-Gillet, Marie-Claire; Gailly, Patrick; Vanheusden, Alain; Mainjot, Amélie

2016-09-01

Polymer-infiltrated-ceramic-network (PICN) materials constitute an innovative class of CAD-CAM materials offering promising perspectives in prosthodontics, but no data are available in the literature regarding their biological properties. The objective of the present study was to evaluate the in vitro biocompatibility of PICNs with human gingival fibroblasts (HGFs) in comparison with materials typically used for implant prostheses and abutments. HGF attachment, proliferation and spreading on discs made of PICN, grade V titanium (Ti), yttrium zirconia (Zi), lithium disilicate glass-ceramic (eM) and polytetrafluoroethylene (negative control), were evaluated using a specific insert-based culture system (IBS-R). Sample surface properties were characterized by XPS, contact angle measurement, profilometry and SEM. Ti and Zi gave the best results regarding HGF viability, morphology, number and coverage increase with time in comparison with the negative control, while PICN and eM gave intermediate results, cell spreading being comparable for PICN, Ti, Zi and eM. Despite the presence of polymers and their related hydrophobicity, PICN exhibited comparable results to glass-ceramic materials, which could be explained by the mode of polymerization of the monomers. The results of the present study confirm that the currently employed materials, i.e. Ti and Zi, can be considered to be the gold standard of materials in terms of HGF behavior, while PICN gave intermediate results comparable to eM. The impact of the present in vitro results needs to be further investigated clinically, particularly in the view of the utilization of PICNs for prostheses on bone-level implants. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Nonlinear microstructured polymer optical fibres

DEFF Research Database (Denmark)

Frosz, Michael Henoch

is potentially the case for microstructured polymer optical fibres (mPOFs). Another advantage is that polymer materials have a higher biocompatibility than silica, meaning that it is easier to bond certain types of biosensor materials to a polymer surface than to silica. As with silica PCFs, it is difficult...

Polymer crowding and shape distributions in polymer-nanoparticle mixtures

Energy Technology Data Exchange (ETDEWEB)

Lim, Wei Kang; Denton, Alan R., E-mail: alan.denton@ndsu.edu [Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050 (United States)

2014-09-21

Macromolecular crowding can influence polymer shapes, which is important for understanding the thermodynamic stability of polymer solutions and the structure and function of biopolymers (proteins, RNA, DNA) under confinement. We explore the influence of nanoparticle crowding on polymer shapes via Monte Carlo simulations and free-volume theory of a coarse-grained model of polymer-nanoparticle mixtures. Exploiting the geometry of random walks, we model polymer coils as effective penetrable ellipsoids, whose shapes fluctuate according to the probability distributions of the eigenvalues of the gyration tensor. Accounting for the entropic cost of a nanoparticle penetrating a larger polymer coil, we compute the crowding-induced shift in the shape distributions, radius of gyration, and asphericity of ideal polymers in a theta solvent. With increased nanoparticle crowding, we find that polymers become more compact (smaller, more spherical), in agreement with predictions of free-volume theory. Our approach can be easily extended to nonideal polymers in good solvents and used to model conformations of biopolymers in crowded environments.

Polymer crowding and shape distributions in polymer-nanoparticle mixtures

International Nuclear Information System (INIS)

Lim, Wei Kang; Denton, Alan R.

2014-01-01

Macromolecular crowding can influence polymer shapes, which is important for understanding the thermodynamic stability of polymer solutions and the structure and function of biopolymers (proteins, RNA, DNA) under confinement. We explore the influence of nanoparticle crowding on polymer shapes via Monte Carlo simulations and free-volume theory of a coarse-grained model of polymer-nanoparticle mixtures. Exploiting the geometry of random walks, we model polymer coils as effective penetrable ellipsoids, whose shapes fluctuate according to the probability distributions of the eigenvalues of the gyration tensor. Accounting for the entropic cost of a nanoparticle penetrating a larger polymer coil, we compute the crowding-induced shift in the shape distributions, radius of gyration, and asphericity of ideal polymers in a theta solvent. With increased nanoparticle crowding, we find that polymers become more compact (smaller, more spherical), in agreement with predictions of free-volume theory. Our approach can be easily extended to nonideal polymers in good solvents and used to model conformations of biopolymers in crowded environments

Self healing in polymers and polymer composites. Concepts, realization and outlook: A review

Directory of Open Access Journals (Sweden)

2008-04-01

Full Text Available Formation of microcracks is a critical problem in polymers and polymer composites during their service in structural applications. Development and coalescence of microcracks would bring about catastrophic failure of the materials and then reduce their lifetimes. Therefore, early sensing, diagnosis and repair of microcracks become necessary for removing the latent perils. In this context, the materials possessing self-healing function are ideal for long-term operation. Self-repairing polymers and polymer composites have attracted increasing research interests. Attempts have been made to develop solutions in this field. The present article reviews state-of-art of the achievements on the topic. According to the ways of healing, the smart materials are classified into two categories: (i intrinsic self-healing ones that are able to heal cracks by the polymers themselves, and (ii extrinsic in which healing agent has to be pre-embedded. The advances in this field show that selection and optimization of proper repair mechanisms are prerequisites for high healing efficiency. It is a challenging job to either invent new polymers with inherent crack repair capability or integrate existing materials with novel healing system.

Helix-sense-selective co-precipitation for preparing optically active helical polymer nanoparticles/graphene oxide hybrid nanocomposites.

Science.gov (United States)

Huang, Huajun; Li, Weifei; Shi, Yan; Deng, Jianping

2017-05-25

Constructing optically active helical polymer based nanomaterials without using expensive and limited chirally helical polymers has become an extremely attractive research topic in both chemical and materials science. In this study, we prepared a series of optically active helical polymer nanoparticles/graphene oxide (OAHPNs/GO) hybrid nanocomposites through an unprecedented strategy-the co-precipitation of optically inactive helical polymers and chirally modified GO. This approach is named helix-sense-selective co-precipitation (HSSCP), in which the chirally modified GO acted as a chiral source for inducing and further stabilizing the predominantly one-handed helicity in the optically inactive helical polymers. SEM and TEM images show quite similar morphologies of all the obtained OAHPNs/GO nanocomposites; specifically, the chirally modified GO sheets were uniformly decorated with spherical polymer nanoparticles. Circular dichroism (CD) and UV-vis absorption spectra confirmed the preferentially induced helicity in the helical polymers and the optical activity of the nanocomposites. The established HSSCP strategy is thus proven to be widely applicable and is expected to produce numerous functional OAHPNs/GO nanocomposites and even the analogues.

Morphological studies of polymer dispersed liquid crystal materials

International Nuclear Information System (INIS)

Han, Jin-Woo

2006-01-01

In this work, we have studied the morphologies of polymer dispersed liquid crystals (PDLCs) based on E7/NOA61. Scanning electron microscope studies show that the PDLC morphology is strongly affected by the LC concentration and the cure temperature. A typical PDLC morphology with isolated LC droplets dispersed in a polymer matrix is only observed at low LC compositions and at low cure temperatures. Increasing either the LC composition or the cure temperature results in a polymer ball morphology, in which LCs exist in irregularly shaped voids in the polymer network structure. It is shown that the transition between these two morphologies can be qualitatively explained using a pseudo-binary phase diagram.

Matrix Organization and Merit Factor Evaluation as a Method to Address the Challenge of Finding a Polymer Material for Roll Coated Polymer Solar Cells

DEFF Research Database (Denmark)

Bundgaard, Eva; Livi, Francesco; Hagemann, Ole

2015-01-01

The results presented demonstrate how the screening of 104 light-absorbing low band gap polymers for suitability in roll coated polymer solar cells can be accomplished through rational synthesis according to a matrix where 8 donor and 13 acceptor units are organized in rows and columns. Synthesis...... silver comb back electrode structure. The matrix organization enables fast identification of active layer materials according to a weighted merit factor that includes more than simply the power conversion efficiency and is used as a method to identify the lead candidates. Based on several characteristics...

Direct Creation of Highly Conductive Laser-Induced Graphene Nanocomposites from Polymer Blends.

Science.gov (United States)

Yazdi, Alireza Zehtab; Navas, Ivonne Otero; Abouelmagd, Ahmed; Sundararaj, Uttandaraman

2017-09-01

The current state-of-the-art mixing strategies of nanoparticles with insulating polymeric components have only partially utilized the unique electrical conductivity of graphene in nanocomposite systems. Herein, this paper reports a nonmixing method of direct creation of polymer/graphene nanocomposites from polymer blends via laser irradiation. Polycarbonate-laser-induced graphene (PC-LIG) nanocomposite is produced from a PC/polyetherimide (PC/PEI) blend after exposure to commercially available laser scribing with a power of ≈6 W and a speed of ≈2 cm s -1 . Extremely high electrical conductivities are obtained for the PC-LIG nanocomposites, ranging from 26 to 400 S m -1 , depending on the vol% of the starting PEI phase in the blend. To the authors' knowledge, these conductivity values are at least one order of magnitude higher than the values that are previously reported for conductive polymer/graphene nanocomposites prepared via mixing strategies. The comprehensive microscopy and spectroscopy characterizations reveal a complete graphitization of the PEI phase with columnar microstructure embedded in the PC phase. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

UV-cured polymer optics

Science.gov (United States)

Piñón, Victor; Santiago, Freddie; Vogelsberg, Ashten; Davenport, Amelia; Cramer, Neil

2017-10-01

Although many optical-quality glass materials are available for use in optical systems, the range of polymeric materials is limited. Polymeric materials have some advantages over glass when it comes to large-scale manufacturing and production. In smaller scale systems, they offer a reduction in weight when compared to glass counterparts. This is especially important when designing optical systems meant to be carried by hand. We aimed to expand the availability of polymeric materials by exploring both crown-like and flint-like polymers. In addition, rapid and facile production was also a goal. By using UV-cured thiolene-based polymers, we were able to produce optical materials within seconds. This enabled the rapid screening of a variety of polymers from which we down-selected to produce optical flats and lenses. We will discuss problems with production and mitigation strategies in using UV-cured polymers for optical components. Using UV-cured polymers present a different set of problems than traditional injection-molded polymers, and these issues are discussed in detail. Using these produced optics, we integrated them into a modified direct view optical system, with the end goal being the development of drop-in replacements for glass components. This optical production strategy shows promise for use in lab-scale systems, where low-cost methods and flexibility are of paramount importance.

Covalent organic polymer functionalized activated carbon: A novel material for water contaminant removal and CO2 capture

DEFF Research Database (Denmark)

Mines, Paul D.; Thirion, Damien; Uthuppu, Basil

Covalent organic polymers (COPs) have emerged as one of the leading advanced materials for environmental applications, such as the capture and recovery of carbon dioxide and the removal of contaminants from polluted water. COPs exhibit many remarkable properties that other leading advanced materi...

2014 Global Conference on Polymer and Composite Materials (PCM 2014)

Science.gov (United States)

2014-08-01

The 2014 Global Conference on Polymer and Composite Materials (PCM 2014) sponsored by Ningbo Adhesives and Products Industry Association, Shanghai Bonding Technology Association, Zhejiang Bonding Technology Association, Wuhan Bonding Technology Association, Hebei Bonding and Coatings Association and Polyurethane Industry Association was held from May 27 to May 29 2014 in Ningbo, China. The technical program consisted of 8 international keynote speakers, oral presentations, and a poster session. The conference also included an industrial exhibition where more than 50 companies displayed in their booths their most recent advanced products and services. The present issue of IOP Conference Series: Materials Science and Engineering (MSE) records the proceedings of PCM 2014 and contains 37 specially selected manuscripts submitted to PCM2014 conference. The electronic submission and handling of manuscripts via the conference website, including the selection of reviewers and evaluation of manuscripts, were identical to the procedures applied to manuscripts submitted as regular contributions for publication. The organization of this conference and the preparation of proceedings volumes would have been impossible without the tremendous efforts and dedication of many individuals, especially from Ms. Yin Pan, who oversaw the organization of the conference and the program; and a large team of reviewers with their timely submission of quality reports. We express our sincere thanks to all authors and presenters for their contributions. We also thank very much our sponsors for their generous support. The 2015 Global Conference on Polymer and Composite Materials (PCM2015) will be held in Beijing, China on May 16-18, 2015. Beijing, the capital of the People's Republic of China and one of the most populous cities in the world, will welcome to all participants for a renewed and vibrant conference. Prof. Dr. Esteban Broitman Linköping University, Sweden Editor in Chief — PCM2014

2014 Global Conference on Polymer and Composite Materials (PCM 2014)

International Nuclear Information System (INIS)

2014-01-01

The 2014 Global Conference on Polymer and Composite Materials (PCM 2014) sponsored by Ningbo Adhesives and Products Industry Association, Shanghai Bonding Technology Association, Zhejiang Bonding Technology Association, Wuhan Bonding Technology Association, Hebei Bonding and Coatings Association and Polyurethane Industry Association was held from May 27 to May 29 2014 in Ningbo, China. The technical program consisted of 8 international keynote speakers, oral presentations, and a poster session. The conference also included an industrial exhibition where more than 50 companies displayed in their booths their most recent advanced products and services. The present issue of IOP Conference Series: Materials Science and Engineering (MSE) records the proceedings of PCM 2014 and contains 37 specially selected manuscripts submitted to PCM2014 conference. The electronic submission and handling of manuscripts via the conference website, including the selection of reviewers and evaluation of manuscripts, were identical to the procedures applied to manuscripts submitted as regular contributions for publication. The organization of this conference and the preparation of proceedings volumes would have been impossible without the tremendous efforts and dedication of many individuals, especially from Ms. Yin Pan, who oversaw the organization of the conference and the program; and a large team of reviewers with their timely submission of quality reports. We express our sincere thanks to all authors and presenters for their contributions. We also thank very much our sponsors for their generous support. The 2015 Global Conference on Polymer and Composite Materials (PCM2015) will be held in Beijing, China on May 16–18, 2015. Beijing, the capital of the People's Republic of China and one of the most populous cities in the world, will welcome to all participants for a renewed and vibrant conference. Prof. Dr. Esteban Broitman Linköping University, Sweden Editor in Chief — PCM

Advances in Hybrid Polymer-Based Materials for Sustained Drug Release

Directory of Open Access Journals (Sweden)

Lígia N. M. Ribeiro

2017-01-01

Full Text Available The use of biomaterials composed of organic pristine components has been successfully described in several purposes, such as tissue engineering and drug delivery. Drug delivery systems (DDS have shown several advantages over traditional drug therapy, such as greater therapeutic efficacy, prolonged delivery profile, and reduced drug toxicity, as evidenced by in vitro and in vivo studies as well as clinical trials. Despite that, there is no perfect delivery carrier, and issues such as undesirable viscosity and physicochemical stability or inability to efficiently encapsulate hydrophilic/hydrophobic molecules still persist, limiting DDS applications. To overcome that, biohybrid systems, originating from the synergistic assembly of polymers and other organic materials such as proteins and lipids, have recently been described, yielding molecularly planned biohybrid systems that are able to optimize structures to easily interact with the targets. This work revised the biohybrid DDS clarifying their advantages, limitations, and future perspectives in an attempt to contribute to further research of innovative and safe biohybrid polymer-based system as biomaterials for the sustained release of active molecules.

Core Cross-Linked Multiarm Star Polymers with Aggregation-Induced Emission and Temperature Responsive Fluorescence Characteristics

KAUST Repository

Zhang, Zhen; Bilalis, Panagiotis; Zhang, Hefeng; Gnanou, Yves; Hadjichristidis, Nikolaos

2017-01-01

Aggregation-induced emission (AIE) active core cross-linked multiarm star polymers, carrying polystyrene (PS), polyethylene (PE), or polyethylene-b-polycaprolactone (PE-b-PCL) arms, have been synthesized through an “arm-first” strategy, by atom

Acoustic Performance of Resilient Materials Using Acrylic Polymer Emulsion Resin.

Science.gov (United States)

Kim, Haseog; Park, Sangki; Lee, Seahyun

2016-07-19

There have been frequent cases of civil complaints and disputes in relation to floor impact noises over the years. To solve these issues, a substantial amount of sound resilient material is installed between the concrete slab and the foamed concrete during construction. A new place-type resilient material is made from cement, silica powder, sodium sulfate, expanded-polystyrene, anhydrite, fly ash, and acrylic polymer emulsion resin. Its physical characteristics such as density, compressive strength, dynamic stiffness, and remanent strain are analyzed to assess the acoustic performance of the material. The experimental results showed the density and the dynamic stiffness of the proposed resilient material is increased with proportional to the use of cement and silica powder due to the high contents of the raw materials. The remanent strain, related to the serviceability of a structure, is found to be inversely proportional to the density and strength. The amount of reduction in the heavyweight impact noise is significant in a material with high density, high strength, and low remanent strain. Finally, specimen no. R4, having the reduction level of 3 dB for impact ball and 1 dB for bang machine in the single number quantity level, respectively, is the best product to obtain overall acoustic performance.

Acoustic Performance of Resilient Materials Using Acrylic Polymer Emulsion Resin

Directory of Open Access Journals (Sweden)

Haseog Kim

2016-07-01

Full Text Available There have been frequent cases of civil complaints and disputes in relation to floor impact noises over the years. To solve these issues, a substantial amount of sound resilient material is installed between the concrete slab and the foamed concrete during construction. A new place-type resilient material is made from cement, silica powder, sodium sulfate, expanded-polystyrene, anhydrite, fly ash, and acrylic polymer emulsion resin. Its physical characteristics such as density, compressive strength, dynamic stiffness, and remanent strain are analyzed to assess the acoustic performance of the material. The experimental results showed the density and the dynamic stiffness of the proposed resilient material is increased with proportional to the use of cement and silica powder due to the high contents of the raw materials. The remanent strain, related to the serviceability of a structure, is found to be inversely proportional to the density and strength. The amount of reduction in the heavyweight impact noise is significant in a material with high density, high strength, and low remanent strain. Finally, specimen no. R4, having the reduction level of 3 dB for impact ball and 1 dB for bang machine in the single number quantity level, respectively, is the best product to obtain overall acoustic performance.

A novel and facile strategy for highly flame retardant polymer foam composite materials: Transforming silicone resin coating into silica self-extinguishing layer.

Science.gov (United States)

Wu, Qian; Zhang, Qian; Zhao, Li; Li, Shi-Neng; Wu, Lian-Bin; Jiang, Jian-Xiong; Tang, Long-Cheng

2017-08-15

In this study, a novel strategy was developed to fabricate highly flame retardant polymer foam composite materials coated by synthesized silicone resin (SiR) polymer via a facile dip-coating processing. Applying the SiR polymer coating, the mechanical property and thermal stability of SiR-coated polymer foam (PSiR) composites are greatly enhanced without significantly altering their structure and morphology. The minimum oxygen concentration to support the combustion of foam materials is greatly increased, i.e. from LOI 14.6% for pure foam to LOI 26-29% for the PSiR composites studied. Especially, adjusting pendant group to SiOSi group ratio (R/Si ratio) of SiRs produces highly flame retardant PSiR composites with low smoke toxicity. Cone calorimetry results demonstrate that 44-68% reduction in the peak heat release rate for the PSiR composites containing different R/Si ratios over pure foam is achieved by the presence of appropriate SiR coating. Digital and SEM images of post-burn chars indicate that the SiR polymer coating can be transformed into silica self-extinguishing porous layer as effective inorganic barrier effect, thus preserving the polymer foam structure from fire. Our results show that the SiR dip-coating technique is a promising strategy for producing flame retardant polymer foam composite materials with improved mechanical properties. Copyright © 2017 Elsevier B.V. All rights reserved.

PHOTOREFRACTIVE POLYMERS

NARCIS (Netherlands)

Morichere, D; Malliaras, G.G; Krasnikov, V.V.; Bolink, H.J; Hadziioannou, G

The use of polymers as photorefractive materials offers many advantages : flexibility in synthesis, doping, processing and low cost. The required functionalities responsible for photorefractivity, namely charge generation, transport, trapping and linear electrooptic effect are given in the polymer

Nature's Mechanisms for Tough, Self-healing Polymers and Polymer Adhesives

Science.gov (United States)

Hansma, Paul

2007-03-01

Spider silk^2 and the natural polymer adhesives in abalone shells^3 and bone^4,5 can give us insights into nature's mechanisms for tough, self-healing polymers and polymer adhesives. The natural polymer adhesives in biomaterials have been optimized by evolution. An optimized polymer adhesive has five characteristics. 1) It holds together the strong elements of the composite. 2) It yields just before the strong elements would otherwise break. 3) It dissipates large amounts of energy as it yields. 4) It self heals after it yields. 5) It takes just a few percent by weight. Both natural polymer adhesives and silk rely on sacrificial bonds and hidden length for toughness and self-healing.^6 A relatively large energy, of order 100eV, is required to stretch a polymer molecule after a weak bond, a sacrificial bond, breaks and liberates hidden length, which was previously hidden, typically in a loop or folded domain, from whatever was stretching the polymer. The bond is called sacrificial if it breaks at forces well below the forces that could otherwise break the polymer backbone, typically greater than 1nN. In many biological cases, the breaking of sacrificial bonds has been found to be reversible, thereby also providing a ``self-healing'' property to the material.^2-4 Individual polymer adhesive molecules based on sacrificial bonds and hidden length can supply forces of order 300pN over distances of 100s of nanometers. Model calculations show that a few percent by weight of adhesives based on these principles could be optimized adhesives for high performance composite materials including nanotube and graphene sheet composites. ^2N. Becker, E. Oroudjev, S. Mutz et al., Nature Materials 2 (4), 278 (2003). ^3B. L. Smith, T. E. Schaffer, M. Viani et al., Nature 399 (6738), 761 (1999). ^4J. B. Thompson, J. H. Kindt, B. Drake et al., Nature 414 (6865), 773 (2001). ^5G. E. Fantner, T. Hassenkam, J. H. Kindt et al., Nature Materials 4, 612 (2005). ^6G. E. Fantner, E. Oroudjev, G

CH-π Interaction Driven Macroscopic Property Transition on Smart Polymer Surface

Science.gov (United States)

Li, Minmin; Qing, Guangyan; Xiong, Yuting; Lai, Yuekun; Sun, Taolei

2015-10-01

Life systems have evolved to utilize weak noncovalent interactions, particularly CH-π interaction, to achieve various biofunctions, for example cellular communication, immune response, and protein folding. However, for artificial materials, it remains a great challenge to recognize such weak interaction, further transform it into tunable macroscopic properties and realize special functions. Here we integrate monosaccharide-based CH-π receptor capable of recognizing aromatic peptides into a smart polymer with three-component “Recognition-Mediating-Function” design, and report the CH-π interaction driven surface property switching on smart polymer film, including wettability, adhesion, viscoelasticity and stiffness. Detailed studies indicate that, the CH-π interaction induces the complexation between saccharide unit and aromatic peptide, which breaks the initial amphiphilic balance of the polymer network, resulting in contraction-swelling conformational transition for polymer chains and subsequent dramatic switching in surface properties. This work not only presents a new approach to control the surface property of materials, but also points to a broader research prospect on CH-π interaction at a macroscopic level.

An Examination of Radiation Induced Tensile Failure of Stressed and Unstressed Polymer Films Flown on MISSE-6

Science.gov (United States)

Miller, Sharon K.; Sechkar, Edward A.

2012-01-01

Thin film polymers are used in many spacecraft applications for thermal control (multilayer insulation and sunshields), as lightweight structural members (solar array blankets, inflatable/deployable structures) and have been proposed for propulsion (solar sails). Polymers in these applications are often under a tensile load and are directly exposed to the space environment, therefore it is important to understand the effect of stress in combination with the environment on the durability of these polymer films. The purpose of the Polymer Film Tensile Experiment, flown as part of Materials International Space Station Experiment 6 (MISSE 6), was to expose a variety of polymer films to the low Earth orbital environment under both relaxed and tension conditions. This paper describes the results of post flight tensile testing of these samples.

Polymer Brushes: Synthesis, Characterization, Applications

Science.gov (United States)

Advincula, Rigoberto C.; Brittain, William J.; Caster, Kenneth C.; Rühe, Jürgen

2004-09-01

Materials scientists, polymer chemists, surface physicists and materials engineers will find this book a complete and detailed treatise on the field of polymer brushes, their synthesis, characterization and manifold applications. In a first section, the various synthetic pathways and different surface materials are introduced and explained, followed by a second section covering important aspects of characterization and analysis in both flat surfaces and particles. These specific surface initiated polymerization (SIP) systems such as linear polymers, homopolymers, block copolymers, and hyperbranched polymers are unique compared to previously reported systems by chemisorption or physisorption. They have found their way in both large-scale and miniature applications of polymer brushes, which is covered in the last section. Such 'hairy' surfaces offer fascinating opportunities for addressing numerous problems of both academic and, in particular, industrial interest: high-quality, functional or protective coatings, composite materials, surface engineered particles, metal-organic interfaces, biological applications, micro-patterning, colloids, nanoparticles, functional devices, and many more. It is the desire of the authors that this book will be of benefit to readers who want to "brush-up on polymers".

Structures and Elastic Moduli of Polymer Nanocomposite Thin Films

Science.gov (United States)

Yuan, Hongyi; Karim, Alamgir; University of Akron Team

2014-03-01

Polymeric thin films generally possess unique mechanical and thermal properties due to confinement. In this study we investigated structures and elastic moduli of polymer nanocomposite thin films, which can potentially find wide applications in diverse areas such as in coating, permeation and separation. Conventional thermoplastics (PS, PMMA) and biopolymers (PLA, PCL) were chosen as polymer matrices. Various types of nanoparticles were used including nanoclay, fullerene and functionalized inorganic particles. Samples were prepared by solvent-mixing followed by spin-coating or flow-coating. Film structures were characterized using X-ray scattering and transmission electron microscopy. Elastic moduli were measured by strain-induced elastic buckling instability for mechanical measurements (SIEBIMM), and a strengthening effect was found in certain systems due to strong interaction between polymers and nanoparticles. The effects of polymer structure, nanoparticle addition and film thickness on elastic modulus will be discussed and compared with bulk materials.

Accelerating materials discovery through the development of polymer databases

Science.gov (United States)

Audus, Debra

In our line of business we create chemical solutions for a wide range of applications, such as home and personal care, printing and packaging, automotive and structural coatings, and structural plastics and foams applications. In this environment, stable and highly automated workflows suitable to handle complex systems are a must. By satisfying these prerequisites, efficiency for the development of new materials can be significantly improved by combining modeling and experimental approaches. This is in fact in line with recent Materials Genome Initiative efforts sponsored by the US administration. From our experience, we know, that valuable contributions to product development are possible today by combining existing modeling techniques in an intelligent fashion, provided modeling and experiment work closely together. In my presentation I intend to review approaches to build and parameterize soft matter systems. As an example of our standard workflow, I will show a few applications, which include the design of a stabilizer molecule for dispersing polymer particles and the simulation of polystyrene dispersions.

Graphene-based polymer nanocomposites

NARCIS (Netherlands)

Tkalya, E.

2012-01-01

The main reason for the rapid development of polymer composite materials is that the traditional "pure" polymers have largely played out its performance capabilities whereas technology requires materials with new properties and advances. There are a number of advantages polymeric composites have

Facile preparation of hierarchically porous polymer microspheres for superhydrophobic coating

Science.gov (United States)

Gao, Jiefeng; Wong, Julia Shuk-Ping; Hu, Mingjun; Li, Wan; Li, Robert. K. Y.

2013-12-01

A facile method, i.e., nonsolvent assisted electrospraying, is proposed to fabricate hierarchically porous microspheres. The pore size on the microsphere surface ranges from a few tens to several hundred nanometers. Thermally and nonsolvent induced phase separation as well as breath figure is responsible for the formation of the hierarchical structures with different nano-sized pores. The nonsolvent could not only induce phase separation, but also stabilize the interface between the droplet and air, which can prevent the droplet from strong deformation, and is therefore beneficial to the formation of regular and uniform microspheres. On the other hand, solvent evaporation, polymer diffusion and Coulomb fission during electrospraying influence the morphology of finally obtained products. In this paper, the influence of polymer concentration, the weight ratio between nonsolvent and polymer and the flowing rate on the morphology of the porous microsphere is carefully studied. The hierarchically porous microsphere significantly increases the surface roughness and thus the hydrophobicity, and the contact angle can reach as high as 152.2 +/- 1.2°. This nonsolvent assisted electrospraying opens a new way to fabricate superhydrophobic coating materials.A facile method, i.e., nonsolvent assisted electrospraying, is proposed to fabricate hierarchically porous microspheres. The pore size on the microsphere surface ranges from a few tens to several hundred nanometers. Thermally and nonsolvent induced phase separation as well as breath figure is responsible for the formation of the hierarchical structures with different nano-sized pores. The nonsolvent could not only induce phase separation, but also stabilize the interface between the droplet and air, which can prevent the droplet from strong deformation, and is therefore beneficial to the formation of regular and uniform microspheres. On the other hand, solvent evaporation, polymer diffusion and Coulomb fission during

Preparation and application of conducting polymer/Ag/clay composite nanoparticles formed by in situ UV-induced dispersion polymerization

Science.gov (United States)

Zang, Limin; Qiu, Jianhui; Yang, Chao; Sakai, Eiichi

2016-02-01

In this work, composite nanoparticles containing polypyrrole, silver and attapulgite (PPy/Ag/ATP) were prepared via UV-induced dispersion polymerization of pyrrole using ATP clay as a templet and silver nitrate as photoinitiator. The effects of ATP concentration on morphology, structure and electrical conductivity were studied. The obtained composite nanoparticles with an interesting beads-on-a-string morphology can be obtained in a short time (10 min), which indicates the preparation method is facile and feasible. To explore the potential applications of the prepared PPy/Ag/ATP composite nanoparticles, they were served as multifunctional filler and blended with poly(butylene succinate) (PBS) matrix to prepare biodegradable composite material. The distribution of fillers in polymer matrix and the interfacial interaction between fillers and PBS were confirmed by scanning electron microscope, elemental mapping and dynamic mechanical analysis. The well dispersed fillers in PBS matrix impart outstanding antibacterial property to the biodegradable composite material as well as enhanced storage modulus due to Ag nanoparticles and ATP clay. The biodegradable composite material also possesses modest surface resistivity (106 ~ 109 Ω/◻).

Preparation and application of conducting polymer/Ag/clay composite nanoparticles formed by in situ UV-induced dispersion polymerization.

Science.gov (United States)

Zang, Limin; Qiu, Jianhui; Yang, Chao; Sakai, Eiichi

2016-02-03

In this work, composite nanoparticles containing polypyrrole, silver and attapulgite (PPy/Ag/ATP) were prepared via UV-induced dispersion polymerization of pyrrole using ATP clay as a templet and silver nitrate as photoinitiator. The effects of ATP concentration on morphology, structure and electrical conductivity were studied. The obtained composite nanoparticles with an interesting beads-on-a-string morphology can be obtained in a short time (10 min), which indicates the preparation method is facile and feasible. To explore the potential applications of the prepared PPy/Ag/ATP composite nanoparticles, they were served as multifunctional filler and blended with poly(butylene succinate) (PBS) matrix to prepare biodegradable composite material. The distribution of fillers in polymer matrix and the interfacial interaction between fillers and PBS were confirmed by scanning electron microscope, elemental mapping and dynamic mechanical analysis. The well dispersed fillers in PBS matrix impart outstanding antibacterial property to the biodegradable composite material as well as enhanced storage modulus due to Ag nanoparticles and ATP clay. The biodegradable composite material also possesses modest surface resistivity (10(6)~ 10(9) Ω/◻).

Surface Modification of Polymer Substrates for Biomedical Applications

Directory of Open Access Journals (Sweden)

Oldřich Neděla

2017-09-01

Full Text Available While polymers are widely utilized materials in the biomedical industry, they are rarely used in an unmodified state. Some kind of a surface treatment is often necessary to achieve properties suitable for specific applications. There are multiple methods of surface treatment, each with their own pros and cons, such as plasma and laser treatment, UV lamp modification, etching, grafting, metallization, ion sputtering and others. An appropriate treatment can change the physico-chemical properties of the surface of a polymer in a way that makes it attractive for a variety of biological compounds, or, on the contrary, makes the polymer exhibit antibacterial or cytotoxic properties, thus making the polymer usable in a variety of biomedical applications. This review examines four popular methods of polymer surface modification: laser treatment, ion implantation, plasma treatment and nanoparticle grafting. Surface treatment-induced changes of the physico-chemical properties, morphology, chemical composition and biocompatibility of a variety of polymer substrates are studied. Relevant biological methods are used to determine the influence of various surface treatments and grafting processes on the biocompatibility of the new surfaces—mammalian cell adhesion and proliferation is studied as well as other potential applications of the surface-treated polymer substrates in the biomedical industry.

Core Cross-Linked Multiarm Star Polymers with Aggregation-Induced Emission and Temperature Responsive Fluorescence Characteristics

KAUST Repository

Zhang, Zhen

2017-05-19

Aggregation-induced emission (AIE) active core cross-linked multiarm star polymers, carrying polystyrene (PS), polyethylene (PE), or polyethylene-b-polycaprolactone (PE-b-PCL) arms, have been synthesized through an “arm-first” strategy, by atom transfer radical copolymerization (ATRP) of a double styrene-functionalized tetraphenylethene (TPE-2St) used as a cross-linker with linear arm precursors possessing terminal ATRP initiating moieties. Polyethylene macroinitiator (PE–Br) was prepared via the polyhomologation of dimethylsulfoxonium methylide with triethylborane followed by oxidation/hydrolysis and esterification of the produced PE–OH with 2-bromoisobutyryl bromide; polyethylene-block-poly(ε-caprolactone) diblock macroinitiator was derived by combining polyhomologation with ring-opening polymerization (ROP). All synthesized star polymers showed AIE-behavior either in solution or in bulk. At high concentration in good solvents (e.g., THF, or toluene) they exhibited low photoluminescence (PL) intensity due to the inner filter effect. In sharp contrast to the small molecule TPE-2St, the star polymers were highly emissive in dilute THF solutions. This can be attributed to the cross-linked structure of poly(TPE-2St) core which restricts the intramolecular rotation and thus induces emission. In addition, the PL intensity of PE star polymers in THF(solvent)/n-hexane(nonsolvent) mixtures, due to their nearly spherical shape, increased when the temperature decreased from 55 to 5 °C with a linear response in the range 40–5 °C.

Polymer reaction engineering, an integrated approach

NARCIS (Netherlands)

Meyer, T.; Keurentjes, J.T.F.; Meyer, T.; Keurentjes, J.T.F.

2005-01-01

Summary This chapter contains sections titled: Polymer Materials A Short History of Polymer Reaction Engineering The Position of Polymer Reaction Engineering Toward Integrated Polymer Reaction Engineering The Disciplines in Polymer Reaction Engineering The Future: Product-inspired Polymer Reaction

Improving the long-term stability of PBDTTPD polymer solar cells through material purification aimed at removing organic impurities

KAUST Repository

Mateker, William R.; Douglas, Jessica D.; Cabanetos, Clement; Sachs-Quintana, I. T.; Bartelt, Jonathan A.; Hoke, Eric T.; El Labban, Abdulrahman; Beaujuge, Pierre; Frechet, Jean; McGehee, Michael D.

2013-01-01

While bulk heterojunction (BHJ) solar cells fabricated from high M n PBDTTPD achieve power conversion efficiencies (PCE) as high as 7.3%, the short-circuit current density (JSC) of these devices can drop by 20% after seven days of storage in the dark and under inert conditions. This degradation is characterized by the appearance of S-shape features in the reverse bias region of current-voltage (J-V) curves that increase in amplitude over time. Conversely, BHJ solar cells fabricated from low Mn PBDTTPD do not develop S-shaped J-V curves. However, S-shapes identical to those observed in high Mn PBDTTPD solar cells can be induced in low M n devices through intentional contamination with the TPD monomer. Furthermore, when high Mn PBDTTPD is purified via size exclusion chromatography (SEC) to reduce the content of low molecular weight species, the JSC of polymer devices is significantly more stable over time. After 111 days of storage in the dark under inert conditions, the J-V curves do not develop S-shapes and the JSC degrades by only 6%. The S-shape degradation feature, symptomatic of low device lifetimes, appears to be linked to the presence of low molecular weight contaminants, which may be trapped within samples of high Mn polymer that have not been purified by SEC. Although these impurities do not affect initial device PCE, they significantly reduce device lifetime, and solar cell stability is improved by increasing the purity of the polymer materials. © 2013 The Royal Society of Chemistry.

Polymer Design and Processing for Liquid-Core waveguides

DEFF Research Database (Denmark)

Sagar, Kaushal Shashikant

precursor material. Upon attaining thermodynamically stable gyroid phase segregation, nanoporosity is induced by chemically removing PDMS, the so-called sacrificial block. The isotropic nanoporosity in the polymer is utilized in fabricating a novel type of waveguides for opto-fluidic applications, which we...... are spontaneously filled with water by capillary suction, forming the core, while the unmodified hydrophobic regions remain dry, forming the clad. Two types of photo-modification reactions are presented in this thesis: photo-oxidation and thiol-ene photo-clicking. The hydrophilicity is firstly induced by surface...

Porous Polymer Drug-Eluting Coating Prepared by Radiation Induced Polymerization

Energy Technology Data Exchange (ETDEWEB)

Veres, M.; Tóth, S.; Koós, M. [Research Institute for Solid State Physics and Optics, Budapest (Hungary); Beiler, B. [Institute of Isotopes, HAS, Budapest (Hungary)

2009-07-01

Drug-eluting stents have several advantages over bare metal implants. They eliminate restenosis, the main drawback of bare metal stents. In addition the locally delivered drug is more effective and causes less side-effects. However in some cases dangerous stent thrombosis, inflammatory and allergy reactions were observed after their implantation, which first of all related to the drug-eluting coating. This project is aimed to develop a novel biocompatible nanoporous polymer layer by radiation induced polymerization that is capable of holding and eluting drugs and promotes endothelization after the release of the drug. (author)

Porous Polymer Drug-Eluting Coating Prepared by Radiation Induced Polymerization

International Nuclear Information System (INIS)

Veres, M.; Tóth, S.; Koós, M.; Beiler, B.

2009-01-01

Drug-eluting stents have several advantages over bare metal implants. They eliminate restenosis, the main drawback of bare metal stents. In addition the locally delivered drug is more effective and causes less side-effects. However in some cases dangerous stent thrombosis, inflammatory and allergy reactions were observed after their implantation, which first of all related to the drug-eluting coating. This project is aimed to develop a novel biocompatible nanoporous polymer layer by radiation induced polymerization that is capable of holding and eluting drugs and promotes endothelization after the release of the drug. (author)

Radiation effects in polymers for plastic scintillation detectors

International Nuclear Information System (INIS)

Pla-Dalmau, A.; Bross, A.D.; Hurlbut, C.R.; Moser, S.W.

1994-01-01

Recent developments in both scintillating plastic optical fibers and photon detection devices have spawned new applications for plastic scintillator detectors. This renewed attention has encouraged research that addresses the radiation stability of plastic scintillators. The optical quality of the polymer degrades with exposure to ionizing radiation and thus the light yield of the detector decreases. A complete understanding of all the mechanisms contributing to this radiation-induced degradation of the polymer can lead to techniques that will extend the radiation stability of these materials. Various radiation damage studies have been performed under different atmospheres and dose rates. Currently, the use of additives to preserve the optical properties of the polymer matrix under radiation is being investigated. The authors discuss the effect of certain antioxidants, plasticizers, and cross-linking agents on the radiation resilience of plastic scintillators

Novel fluorinated polymer materials based on 2,3,5,6-tetrafluoro-4-methoxystyrene

DEFF Research Database (Denmark)

Hvilsted, Søren; Borkar, Sachin; Siesler, HW

2003-01-01

2,3,5,6-Tetrafluoro-4-methoxystyrene (TFMS) has been polymerized in bulk and in xylene solution by Atom Transfer Radical Polymerization (ATRP) in a conventional protocol at 110 degreesC. Relatively good control has been achieved with number-average molecular mass (M) up to 17,000 and correspondin...... with different azobenzene side chains. The azobenzene derivatized polymer has additionally been copolymerized with St. Both homo- and block copolymers with azobenzene side chains form materials exhibiting liquid crystallinity.......) resulting in block copolymers with controlled characteristics. TFMS homo- and block copolymers with PS have better thermal stability than PS. The solubility of the PTFMS containing polymers is lower than that of PS. Furthermore, PTFMS has been demethylated and the resulting hydroxyl sites alkylated...

Properties and applications of polymer nanocomposites clay and carbon based polymer nanocomposites

CERN Document Server

Prasad Sahoo, Bibhu

2017-01-01

The aim of the present edited book is to furnish scientific information about manufacturing, properties, and application of clay and carbon based polymer nanocomposites. It can be used as handbook for undergraduate and post graduate courses (for example material science and engineering, polymer science and engineering, rubber technology, manufacturing engineering, etc.) as well as as reference book for research fellows and professionals. Polymer nanocomposites have received outstanding importance in the present decade because of their broad range of high-performance applications in various areas of engineering and technology due to their special material properties. A great interest is dedicated to nanofiller based polymeric materials, which exhibit excellent enhancement in macroscopic material properties (mechanical, thermal, dynamic mechanical, electrical and many more) at very low filler contents and can therefore be used for the development of next-generation composite materials.

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science. A S Singha. Articles written in Bulletin of Materials Science. Volume 31 Issue 1 February 2008 pp 7-13 Polymers. Pressure induced graft-co-polymerization of acrylonitrile onto Saccharum cilliare fibre and evaluation of some properties of grafted fibre · A S Singha Anjali Shama ...

Laser-induced damage in optical materials

CERN Document Server

Ristau, Detlev

2014-01-01

Dedicated to users and developers of high-powered systems, Laser-Induced Damage in Optical Materials focuses on the research field of laser-induced damage and explores the significant and steady growth of applications for high-power lasers in the academic, industrial, and military arenas. Written by renowned experts in the field, this book concentrates on the major topics of laser-induced damage in optical materials and most specifically addresses research in laser damage that occurs in the bulk and on the surface or the coating of optical components. It considers key issues in the field of hi

Radiation crosslinking of polymers with segregated metallic particles. Final report, June 1, 1971--September 30, 1973

International Nuclear Information System (INIS)

Corneliussen, R.D.; Kamel, I.; Kusy, R.P.

1973-01-01

Through the past four years of research, a new approach to fabricating conductive polymer/metal composites has been developed. This approach consists of compacting mixtures of polymer and metal powders and then stabilizing the composite through radiation-induced crosslinking. The result is a mechanically strong, conductive materials consisting of two intertwining networks. One is a massive network consisting of fused crosslinked, large (greater than 100 μ) polymer particles while the other is a fine network of small, metallic particles (greater than 10 μ). Nine different systems including crystalline, amorphous, and rubbery polymers were studied. Processing at this time is limited to compression molding in a closed die because of network stability problems. Costs for processing were estimated at about $6.00/lb compared to $50.00 and up for commercial material based on random networks. (U.S.)

The usage of carbon fiber reinforcement polymer and glass fiber reinforcement polymer for retrofit technology building

Science.gov (United States)

Tarigan, Johannes; Meka, Randi; Nursyamsi

2018-03-01

Fiber Reinforcement Polymer has been used as a material technology since the 1970s in Europe. Fiber Reinforcement Polymer can reinforce the structure externally, and used in many types of buildings like beams, columns, and slabs. It has high tensile strength. Fiber Reinforcement Polymer also has high rigidity and strength. The profile of Fiber Reinforcement Polymer is thin and light, installation is simple to conduct. One of Fiber Reinforcement Polymer material is Carbon Fiber Reinforcement Polymer and Glass Fiber Reinforcement Polymer. These materials is tested when it is installed on concrete cylinders, to obtain the comparison of compressive strength CFRP and GFRP. The dimension of concrete is diameter of 15 cm and height of 30 cm. It is amounted to 15 and divided into three groups. The test is performed until it collapsed to obtain maximum load. The results of research using CFRP and GFRP have shown the significant enhancement in compressive strength. CFRP can increase the compressive strength of 26.89%, and GFRP of 14.89%. For the comparison of two materials, CFRP is more strengthening than GFRP regarding increasing compressive strength. The usage of CFRP and GFRP can increase the loading capacity.

Quantification of encapsulated bioburden in spacecraft polymer materials by cultivation-dependent and molecular methods.

Directory of Open Access Journals (Sweden)

Anja Bauermeister

Full Text Available Bioburden encapsulated in spacecraft polymers (such as adhesives and coatings poses a potential risk to jeopardize scientific exploration of other celestial bodies. This is particularly critical for spacecraft components intended for hard landing. So far, it remained unclear if polymers are indeed a source of microbial contamination. In addition, data with respect to survival of microbes during the embedding/polymerization process are sparse. In this study we developed testing strategies to quantitatively examine encapsulated bioburden in five different polymers used frequently and in large quantities on spaceflight hardware. As quantitative extraction of the bioburden from polymerized (solid materials did not prove feasible, contaminants were extracted from uncured precursors. Cultivation-based analyses revealed <0.1-2.5 colony forming units (cfu per cm3 polymer, whereas quantitative PCR-based detection of contaminants indicated considerably higher values, despite low DNA extraction efficiency. Results obtained from this approach reflect the most conservative proxy for encapsulated bioburden, as they give the maximum bioburden of the polymers irrespective of any additional physical and chemical stress occurring during polymerization. To address the latter issue, we deployed an embedding model to elucidate and monitor the physiological status of embedded Bacillus safensis spores in a cured polymer. Staining approaches using AlexaFluor succinimidyl ester 488 (AF488, propidium monoazide (PMA, CTC (5-cyano-2,3-diotolyl tetrazolium chloride demonstrated that embedded spores retained integrity, germination and cultivation ability even after polymerization of the adhesive Scotch-Weld 2216 B/A. Using the methods presented here, we were able to estimate the worst case contribution of encapsulated bioburden in different polymers to the bioburden of spacecraft. We demonstrated that spores were not affected by polymerization processes. Besides Planetary

Second- and third-harmonic generation as a local probe for nanocrystal-doped polymer materials with a suppressed optical breakdown threshold

Science.gov (United States)

Konorov, S. O.; Fedotov, A. B.; Ivanov, A. A.; Alfimov, M. V.; Zabotnov, S. V.; Naumov, A. N.; Sidorov-Biryukov, D. A.; Podshivalov, A. A.; Petrov, A. N.; Fornarini, L.; Carpanese, M.; Ferrante, G.; Fantoni, R.; Zheltikov, A. M.

2003-09-01

Second- and third-harmonic generation processes are shown to allow the detection of absorptive agglomerates of nanocrystals in transparent materials and the visualization of optical breakdown in nanocomposite materials. Correlations between laser-induced breakdown and the behavior of the second- and third-harmonic signals produced in SiC/PMMA nanocomposite films are studied. The potential of second- and third-harmonic generation for the on-line visualization of laser breakdown in nanocomposite polymer materials is revealed, with the ablative material removal being monitored by the decay of the second- and third-harmonic signals. The second and third harmonics generated around the optical breakdown threshold by 75-fs pulses of 1.25-μm Cr:forsterite laser radiation are respectively more than two and four orders of magnitude more intense than the second and third harmonics produced under identical conditions by 40-ps pulses of a Nd:YAG laser. The breakdown threshold for PMMA films doped with 10-20-nm SiC nanocrystals forming absorptive agglomerates are demonstrated to be more than an order of magnitude lower than the breakdown threshold for crystalline SiC and about an order of magnitude lower than that for nondoped PMMA films.

Study of Polymer Material Aging by Laser Mass Spectrometry, UV-Visible Spectroscopy, and Environmental Scanning Electron Microscopy

OpenAIRE

Junien Exposito; Claude Becker; David Ruch; Frédéric Aubriet

2007-01-01

Dyed natural rubber (NR) and styrene butadiene rubber (SBR), designed for outdoor applications, were exposed to an accelerated artificial aging in xenon light. The aging results in the deterioration of the exposed surface material properties. The ability of dyed polymers to withstand prolonged sunlight exposure without fading or undergoing any physical deterioration is largely determined not only by the photochemical characteristics of the absorbing dyestuff itself but also by the polymer str...

Hole-Transfer Dependence on Blend Morphology and Energy Level Alignment in Polymer: ITIC Photovoltaic Materials.

Science.gov (United States)

Eastham, Nicholas D; Logsdon, Jenna L; Manley, Eric F; Aldrich, Thomas J; Leonardi, Matthew J; Wang, Gang; Powers-Riggs, Natalia E; Young, Ryan M; Chen, Lin X; Wasielewski, Michael R; Melkonyan, Ferdinand S; Chang, Robert P H; Marks, Tobin J

2018-01-01

Bulk-heterojunction organic photovoltaic materials containing nonfullerene acceptors (NFAs) have seen remarkable advances in the past year, finally surpassing fullerenes in performance. Indeed, acceptors based on indacenodithiophene (IDT) have become synonymous with high power conversion efficiencies (PCEs). Nevertheless, NFAs have yet to achieve fill factors (FFs) comparable to those of the highest-performing fullerene-based materials. To address this seeming anomaly, this study examines a high efficiency IDT-based acceptor, ITIC, paired with three donor polymers known to achieve high FFs with fullerenes, PTPD3T, PBTI3T, and PBTSA3T. Excellent PCEs up to 8.43% are achieved from PTPD3T:ITIC blends, reflecting good charge transport, optimal morphology, and efficient ITIC to PTPD3T hole-transfer, as observed by femtosecond transient absorption spectroscopy. Hole-transfer is observed from ITIC to PBTI3T and PBTSA3T, but less efficiently, reflecting measurably inferior morphology and nonoptimal energy level alignment, resulting in PCEs of 5.34% and 4.65%, respectively. This work demonstrates the importance of proper morphology and kinetics of ITIC → donor polymer hole-transfer in boosting the performance of polymer:ITIC photovoltaic bulk heterojunction blends. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Trehalose and Trehalose-based Polymers for Environmentally Benign, Biocompatible and Bioactive Materials

Directory of Open Access Journals (Sweden)

Mitsuhiro Shibata

2008-08-01

Full Text Available Abstract: Trehalose is a non-reducing disaccharide that is found in many organisms but not in mammals. This sugar plays important roles in cryptobiosis of selaginella mosses, tardigrades (water bears, and other animals which revive with water from a state of suspended animation induced by desiccation. The interesting properties of trehalose are due to its unique symmetrical low-energy structure, wherein two glucose units are bonded face-to-face by 1→1-glucoside links. The Hayashibara Co. Ltd., is credited for developing an inexpensive, environmentally benign and industrial-scale process for the enzymatic conversion of α-1,4-linked polyhexoses to α,α-D-trehalose, which made it easy to explore novel food, industrial, and medicinal uses for trehalose and its derivatives. Trehalosechemistry is a relatively new and emerging field, and polymers of trehalose derivatives appear environmentally benign, biocompatible, and biodegradable. The discriminating properties of trehalose are attributed to its structure, symmetry, solubility, kinetic and thermodynamic stability and versatility. While syntheses of trehalose-based polymer networks can be straightforward, syntheses and characterization of well defined linear polymers with tailored properties using trehalose-based monomers is challenging, and typically involves protection and deprotection of hydroxyl groups to attain desired structural, morphological, biological, and physical and chemical properties in the resulting products. In this review, we will overview known literature on trehalose’s fascinating involvement in cryptobiology; highlight its applications in many fields; and then discuss methods we used to prepare new trehalose-based monomers and polymers and explain their properties.

Optically induced surface relief phenomena in azobenzene polymers

DEFF Research Database (Denmark)

Holme, NCR; Nikolova, Ludmila; Hvilsted, Søren

1999-01-01

Azobenzene polymers and oligomers show intriguing surface relief features when irradiated with polarized laser light. We show through atomic force microscopic investigation of side-chain azobenzene polymers after irradiation through an amplitude mask that large peaks or trenches result depending...... on the architecture of the polymer. Extensive mass transport over long distances has been observed, paving the way for easy replication of nanostructures. We also show that it is possible to store microscopic images as topographic features in the polymers just through polarized light irradiation. (C) 1999 American...... Institute of Physics....

Next Generation Solvent - Materials Compatibility With Polymer Components Within Modular Caustic-Side Solvent Extraction Unit (Final Report)

International Nuclear Information System (INIS)

Fondeur, F.; Peters, T.; Fink, S.

2012-01-01

The Office of Waste Processing, within the Office of Technology Innovation and Development, is funding the development of an enhanced solvent for deployment at the Savannah River Site for removal of cesium from High Level Waste. The technical effort is collaboration between Oak Ridge National Laboratory (ORNL), Savannah River National Laboratory (SRNL), and Argonne National Laboratory. The first deployment target for the technology is within the Modular Caustic-Side Solvent Extraction Unit (MCU). Deployment of a new chemical within an existing facility requires verification that the chemical components are compatible with the installed equipment. In the instance of a new organic solvent, the primary focus is on compatibility of the solvent with organic polymers used in the facility. This report provides the data from exposing these polymers to the Next Generation Solvent (NGS). The test was conducted over six months. An assessment of the dimensional stability of polymers present in MCU (i.e., PEEK, Grafoil, Tefzel and Isolast) in the modified NGS (where the concentration of LIX(reg s ign)79 and MaxCalix was varied systematically) showed that LIX(reg s ign)79 selectively affected Tefzel and its different grades (by an increase in size and lowering its density). The copolymer structure of Tefzel and possibly its porosity allows for the easier diffusion of LIX(reg s ign)79. Tefzel is used as the seat material in some of the valves at MCU. Long term exposure to LIX(reg s ign)79, may make the valves hard to operate over time due to the seat material (Tefzel) increasing in size. However, since the physical changes of Tefzel in the improved solvent are comparable to the changes in the CSSX baseline solvent, no design changes are needed with respect to the Tefzel seating material. PEEK, Grafoil and Isolast were not affected by LIX(reg s ign)79 and MaxCalix within six months of exposure. The initial rapid weight gain observed in every polymer is assigned to the finite and

NEXT GENERATION SOLVENT-MATERIALS COMPATIBILITY WITH POLYMER COMPONENTS WITHIN MODULAR CAUSTIC-SIDE SOLVENT EXTRACTION UNIT (FINAL REPORT)

Energy Technology Data Exchange (ETDEWEB)

Fondeur, F.; Peters, T.; Fink, S.

2012-01-17

The Office of Waste Processing, within the Office of Technology Innovation and Development, is funding the development of an enhanced solvent for deployment at the Savannah River Site for removal of cesium from High Level Waste. The technical effort is collaboration between Oak Ridge National Laboratory (ORNL), Savannah River National Laboratory (SRNL), and Argonne National Laboratory. The first deployment target for the technology is within the Modular Caustic-Side Solvent Extraction Unit (MCU). Deployment of a new chemical within an existing facility requires verification that the chemical components are compatible with the installed equipment. In the instance of a new organic solvent, the primary focus is on compatibility of the solvent with organic polymers used in the facility. This report provides the data from exposing these polymers to the Next Generation Solvent (NGS). The test was conducted over six months. An assessment of the dimensional stability of polymers present in MCU (i.e., PEEK, Grafoil, Tefzel and Isolast) in the modified NGS (where the concentration of LIX{reg_sign}79 and MaxCalix was varied systematically) showed that LIX{reg_sign}79 selectively affected Tefzel and its different grades (by an increase in size and lowering its density). The copolymer structure of Tefzel and possibly its porosity allows for the easier diffusion of LIX{reg_sign}79. Tefzel is used as the seat material in some of the valves at MCU. Long term exposure to LIX{reg_sign}79, may make the valves hard to operate over time due to the seat material (Tefzel) increasing in size. However, since the physical changes of Tefzel in the improved solvent are comparable to the changes in the CSSX baseline solvent, no design changes are needed with respect to the Tefzel seating material. PEEK, Grafoil and Isolast were not affected by LIX{reg_sign}79 and MaxCalix within six months of exposure. The initial rapid weight gain observed in every polymer is assigned to the finite and

Novel functional materials from renewable lipids: Amphiphilic antimicrobial polymers and latent heat thermal energy storage

Science.gov (United States)

Floros, Michael Christopher

Vegetable oils represent an ideal and renewable feedstock for the synthesis of a variety of functional materials. However, without financial incentive or unique applications motivating a switch, commercial products continue to be manufactured from petrochemical resources. Two different families of high value, functional materials synthesized from vegetable oils were studied. These materials demonstrate superior and unique performance to comparable petrochemical analogues currently on the market. In the first approach, 3 amphiphilic thermoplastic polytriazoles with differing lipophilic segment lengths were synthesized in a polymerization process without solvents or catalysts. Investigation of monomer structure influence on the resultant functional behaviour of these polymers found distinctive odd/even behaviour reliant on the number of carbon atoms in the monomers. Higher concentrations of triazole groups, due to shorter CH2 chains in the monomeric dialkynes, resulted in more brittle polymers, displaying higher tensile strengths but reduced elongation to break characteristics. These polymers had similar properties to commercial petroleum derived thermoplastics. One polymer demonstrated self-assembled surface microstructuring, and displayed hydrophobic properties. Antimicrobial efficacy of the polymers were tested by applying concentrated bacterial solutions to the surfaces, and near complete inhibition was demonstrated after 4 hours. Scanning electron microscope images of killed bacteria showed extensive membrane damage, consistent with the observed impact of other amphiphilic compounds in literature. These polytriazoles are suited for applications in medical devices and implants, where major concerns over antibiotic resistance are prevalent. In the second approach, a series of symmetric, saturated diester phase change materials (PCMs) were also synthesized with superior latent heat values compared to commercial petrochemical analogues. These diesters exhibit

Correlation between native bonds in a polymeric material and molecular emissions from the laser-induced plasma observed with space and time resolved imaging

Energy Technology Data Exchange (ETDEWEB)

Gregoire, S. [CRITT Materiaux Alsace, 19 rue de St Junien, 67300 Schiltigheim (France); Laboratoire de Recherche des Monuments Historiques, 29 rue de Paris, 77420 Champs-sur-Marne (France); Institut Charles Sadron, CNRS and University of Strasbourg, 23 rue de Loess, 67034 Strasbourg Cedex (France); Motto-Ros, V.; Ma, Q.L.; Lei, W.Q.; Wang, X.C. [Universite de Lyon, F-69622, Lyon, France, Universite Lyon 1, Villeurbanne, CNRS, UMR5579, LASIM (France); Pelascini, F.; Surma, F. [CRITT Materiaux Alsace, 19 rue de St Junien, 67300 Schiltigheim (France); Detalle, V., E-mail: vincent.detalle@culture.gouv.fr [Laboratoire de Recherche des Monuments Historiques, 29 rue de Paris, 77420 Champs-sur-Marne (France); Yu, J. [Universite de Lyon, F-69622, Lyon, France, Universite Lyon 1, Villeurbanne, CNRS, UMR5579, LASIM (France)

2012-08-15

Emissions from C{sub 2} molecules and CN radicals in laser-induced plasmas on polymeric materials were observed with time-resolved spectroscopic imaging. More precisely, differential imaging with a pair of narrowband filters (one centered on the emission line and another out of the line) was used to extract emission images of interested molecules or radicals. The correlation between the molecular emission image of the plasma and the molecular structure of the polymer to be analyzed was studied for four different types of materials: polyamide (PA) with native CN bonds, polyethylene (PE) with simple CC bonds, polystyrene (PS) with delocalized double CC bonds, and polyoxymethylene (POM) which neither contains CC nor CN bonds. A clear correlation is demonstrated between emission and molecular structure of the material, allowing the identification of several organic compounds by differential spectroscopic imaging. - Highlights: Black-Right-Pointing-Pointer Plasma imaging method to discriminate different type of polymers. Black-Right-Pointing-Pointer Molecular emissions (CN and C{sub 2}) are spatially and temporally correlated to native bonds. Black-Right-Pointing-Pointer Several formation processes of molecular fragments are observed.

Mechanically Invisible Polymer Coatings

DEFF Research Database (Denmark)

2014-01-01

phase comprises particles, said particles comprising a filler material and an encapsulating coating of a second polymeric material, wherein the backbones of the first and second polymeric materials are the same. The composition may be used in electroactive polymers (EAPs) in order to obtain mechanically......The present invention relates to a composition comprising encapsulated particles in a polymeric material. The composition comprises a continuous phase and a discontinuous phase incorporated therein, wherein the continuous phase comprises a first polymeric material and wherein the discontinuous...... invisible polymer coatings....

Polymer engineering science and viscoelasticity an introduction

CERN Document Server

Brinson, Hal F

2015-01-01

This book provides a unified mechanics and materials perspective on polymers: both the mathematics of viscoelasticity theory as well as the physical mechanisms behind polymer deformation processes. Introductory material on fundamental mechanics is included to provide a continuous baseline for readers from all disciplines. Introductory material on the chemical and molecular basis of polymers is also included, which is essential to the understanding of the thermomechanical response. This self-contained text covers the viscoelastic characterization of polymers including constitutive modeling, experimental methods, thermal response, and stress and failure analysis. Example problems are provided within the text as well as at the end of each chapter.   New to this edition:   ·         One new chapter on the use of nano-material inclusions for structural polymer applications and applications such as fiber-reinforced polymers and adhesively bonded structures ·         Brings up-to-date polymer pro...

AC Electric Field Activated Shape Memory Polymer Composite

Science.gov (United States)

Kang, Jin Ho; Siochi, Emilie J.; Penner, Ronald K.; Turner, Travis L.

2011-01-01

Shape memory materials have drawn interest for applications like intelligent medical devices, deployable space structures and morphing structures. Compared to other shape memory materials like shape memory alloys (SMAs) or shape memory ceramics (SMCs), shape memory polymers (SMPs) have high elastic deformation that is amenable to tailored of mechanical properties, have lower density, and are easily processed. However, SMPs have low recovery stress and long response times. A new shape memory thermosetting polymer nanocomposite (LaRC-SMPC) was synthesized with conductive fillers to enhance its thermo-mechanical characteristics. A new composition of shape memory thermosetting polymer nanocomposite (LaRC-SMPC) was synthesized with conductive functionalized graphene sheets (FGS) to enhance its thermo-mechanical characteristics. The elastic modulus of LaRC-SMPC is approximately 2.7 GPa at room temperature and 4.3 MPa above its glass transition temperature. Conductive FGSs-doped LaRC-SMPC exhibited higher conductivity compared to pristine LaRC SMP. Applying an electric field at between 0.1 Hz and 1 kHz induced faster heating to activate the LaRC-SMPC s shape memory effect relative to applying DC electric field or AC electric field at frequencies exceeding1 kHz.

Influence of polymer charge on the shear yield stress of silica aggregated with adsorbed cationic polymers.

Science.gov (United States)

Zhou, Ying; Yu, Hai; Wanless, Erica J; Jameson, Graeme J; Franks, George V

2009-08-15

Flocs were produced by adding three cationic polymers (10% charge density, 3.0x10(5) g/mol molecular weight; 40% charge density, 1.1x10(5) g/mol molecular weight; and 100% charge density, 1.2x10(5) g/mol molecular weight) to 90 nm diameter silica particles. The shear yield stresses of the consolidated sediment beds from settled and centrifuged flocs were determined via the vane technique. The polymer charge density plays an important role in influencing the shear yield stresses of sediment beds. The shear yield stresses of sediment beds from flocs induced by the 10% charged polymer were observed to increase with an increase in polymer dose, initial solid concentration and background electrolyte concentration at all volume fractions. In comparison, polymer dose has a marginal effect on the shear yield stresses of sediment beds from flocs induced by the 40% and 100% charged polymers. The shear yield stresses of sediments from flocs induced by the 40% charged polymer are independent of salt concentration whereas the addition of salt decreases the shear yield stresses of sediments from flocs induced by the 100% charged polymer. When flocculated at the optimum dose for each polymer (12 mg/g silica for the 10% charged polymer at 0.03 M NaCl, 12 mg/g for 40% and 2 mg/g for 100%), shear yield stress increases as polymer charge increases. The effects observed are related to the flocculation mechanism (bridging, patch attraction or charge neutralisation) and the magnitude of the adhesive force. Comparison of shear and compressive yield stresses show that the network is only slightly weaker in shear than in compression. This is different than many other systems (mainly salt and pH coagulation) which have shear yield stress much less than compressive yield stress. The existing models relating the power law exponent of the volume fraction dependence of the shear yield stress to the network fractal structure are not satisfactory to predict all the experimental behaviour.