bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, characterization and kinetics of hydrophobically associating polyacrylamide
Authors: Hongsheng Lu , Yujun Feng 
Published: August 2014

AbstractHAPAM was successfully prepared in inverse microemulsion. 1H-NMR, FT-IR, DSC and TG results show that the copolymerization of acrylamide (AM) with DM16 was successful. However, the ratio of AM to DM16 is not calculated exactly due to the low percentage of hydrophobic monomer in polymer. Therein, we only proved the success of the incorporation of DM16 onto polyacrylamide backbone. According to our experiment, the conversions of monomers and molecular weight have a strong dependence on initiator concentration and aqueous phase weight fraction. But it was not completely in accordance with literature. The difference may be ascribed to the major existence of locus of DM16 (at the interface of oil/water or in droplet). Compared with literature, the influence of initiator concentration on particle size was slight due to the high surfactant weight fraction, seeming to appear independent of initiator concentration. When the surfactant weight fraction reaches a certain degree, it did not affect the conversion. For the particle size and molecular weight, it was other way around, suggesting that there was an intense chain transfer reaction to the emulsifier. In this work, we could not calculate the average number of free radical per particle n, because the part of the surfactant in excess recombines to form small micelle and the DM16 may continuously transfer from micelle to another micelle, resulting in difficulty to estimate precisely the number of the particles. This was also reflected in the difference of kinetics between our system and literature. Finally, the occurrence of nucleation at high conversion was proved indirectly.
Influence of Ionic Liquids on the Free Radical Copolymerization of Styrene with Acrylonitrile
Authors: Woecht Inga , Schmidt-Naake Gudrun 
Published: August 2014

AbstractFree radical copolymerization of styrene (S) and acrylonitrile (AN) in the ionic liquids (ILs) 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6), 1,3-dimethylimidazolium dimethylphosphate ([MMIM]Me2PO4) and 1-ethyl-3- methylimidazolium ethylsulfate ([EMIM]EtSO4) were investigated. 2,2’-azobisiso butyronitrile (AIBN) and dibenzoyl peroxide (BPO) were used as initiators and dimethyl formamide (DMF) and methanol as reference solvents. The influence of the viscosity on the conversion and the molecular weights was studied by variation of the reaction temperature and the IL concentration. At reaction temperatures of 80 - 85 °C already after 30 minutes a conversion of about 80 % and almost a doubling of the molecular weights is reached for the S/AN (50/50 mol%) copolymerization. In addition the copolymerization behavior of S/AN in [EMIM]EtSO4 was investigated. With increasing concentration of AN in the monomer feed the polymerization rate as well as the molecular weights of the copolymers increase. The influence of the ionic liquid on the copolymer composition, glass-transition temperature and rheological behavior was studied.
Electrospinning of polyamide 6/modified-keratin blends
Authors: Zoccola Marina , Montarsolo Alessio. , Aluigi Annalisa , Varesano Alessio , Vineis Claudia , Tonin Claudio 
Published: August 2014

AbstractProtein material resulting from chemical free steam explosion of wool was mixed in different proportion with polyamide 6 in formic acid. The viscosity of the blend solutions decreases with the increase of the protein amount in the blend. Nanofibres produced by electrospinning of these polymer blends show an increase of the filament diameters with increasing protein amounts, except for the 30/70 v/v polyamide 6/protein blend, where nanofibres with “beads” defects were produced. In blend films produced by casting, polyamide 6 crystallize in the form of large spherulites prevalently in the α crystalline structure, while protein is totally amorphous and tends to segregate in the course of drying at room temperature. Otherwise, in electrospun nanofibres polyamide 6 and protein show a better miscibility as suggested by spectroscopic and thermal analysis and polyamide 6 shows a higher thermal stability. Moisture regain and water solubility of blend cast films and electrospun nanofibres respectively were also determined.
Development of High Refractive Index Plastics
Authors: Jha G.S. , Seshadri G. , Mohan A. , Khandal R.K. 
Published: August 2014

AbstractOptical plastics have been the priority area of research for material scientists worldwide, mainly, to find alternative materials to glass, a conceptual optical material in use over the years. There are numerous advantages of using plastics for optical applications, in particular for ophthalmic applications over glass. Recently, the researchers have been putting their efforts to develop novel plastic materials to meet requirements of ophthalmic industries. The present review compiles the recent developments in the area of optical plastics. The aim is to present the current state-of-the-art in the field, besides analyzing the various aspects of developing optical plastics. The review presents various possible approaches to achieve the desired properties e.g. high refractive index of the optical plastic materials.
In Vacuum Preparation of Psy-cl-poly(AAm) Superabsorbent and its Applications in Oil - Industry
Authors: Kaith B. S. , Kumar Kiran 
Published: August 2014

AbstractIn the present study Psyllium was modified with acrylamide through chemically induced graft co-polymerization, under the influence of vacuum using potassium persulphate as an initiator. Graft copolymers were further crosslinked with hexamethylene tetramine for their application in removal of water from different water-oil emulsions. The hydrogel was found to be selective in its absorption and maximum absorption of water was found to be 3020%.
Preparation and Characterization of PVA/Boron Polymer Produced by an Electrospinning Technique.
Authors: Uslu I. , Daştan H. , Altaş A. , Yayli A. , Atakol O. , Aksu M. L. 
Published: August 2014

Abstract In this study, poly(vinyl alcohol) were cross-linked with boron in varying concentrations and blend fibers were obtained with diameters ranging from 0.3 μ to 4.0 μm with the use of electrospinning process. The resulting product was characterized by SEM, DSC, and FT-IR techniques. There is no beading tendency in either boron doped or undoped fibers. When the amount of boric acid in PVA solutions was increased the conductivity of the polymer decreased. The data indicated the existence of boron oxide in the polymeric structure and the formation of B-O-C bond. SEM micrographs reveal that higher viscosity favors the formation of thicker fibers. Boron addition seems to disturb the easy detachment of the fibers from the tip of the Taylor Cone
Sulphonated Poly(ethylene terephthalate)/Poly(3-hydroxy butyrate) Blends: Miscibility, Thermal Behavior, and Specific Interactions
Authors: Silva Rafael , Carvalho Gizilene M. , Muniz Edvani C. , Vidotti Gentil J. , Rubira Adley F. 
Published: August 2014

AbstractPETs/PHB blends with different compositions were produced by “casting” method. The blends were investigated by TGA, DSC, 1H and 13C NMR and FTIR. Phase separation occurred during blend preparation. PETs and PHB were present in both formed phases. The phases presented different thermal stabilities unrelated to phase component concentration changes. The miscibility study by DSC showed that PHB-phase rich blends are immiscible, whereas the PETs-rich phase blends are miscible. The 1H NMR spectra of the miscible blends exhibited a peak close to the PHB methylene signal, which is in accordance with the interaction between the PETs SO3 - groups and the PHB carbonyl groups. This interaction result in a shift of the PHB carbonyl group absorption band in the FTIR spectra and a variation in the chemical shift of the PHB carbonyl group resonance peak in solid state 13C NMR. No specific interaction was observed for the immiscible blends.
Investigation of the properties of PBT/ABS-g-GMA blends modified with epoxy resin of mid-molecular weights
Authors: Shulin Sun , Zhicheng Chen , Zhiyong Tan , Chao Zhou , Mingyao Zhang , Huixuan Zhang 
Published: August 2014

Abstract Middle molecular weight epoxy resin was used to modify the properties of polybutylene terephthalate (PBT) and glycidyl methacrylate-functionalized acrylonitrile-butadiene-styrene (ABS-g- GMA) blends. Rheological tests showed that the complex viscosity and storage modulus of PBT increased with the addition of epoxy resin due to the chemical reactions. PBT displayed non- Newtanian fluid behaviour when epoxy resin content was 10wt% or higher. SEM results showed there was no obvious difference between the morphology of PBT/ABS-g-GMA blends when epoxy resin content was low, however, agglomeration of ABS phase took place when epoxy resin content was 10wt% or higher due to the complicated reactions. DSC results showed that the addition of epoxy resin to PBT/ABS-g-GMA blends improved the compatibility according to Tm depression criterion and DMA test further testified the improved compatibility. Mechanical tests showed impact strength of 902J/m and yield strength of 42MPa was achieved when 20wt% ABS-g-GMA and 5wt% epoxy resin were used, which displayed supper-toughness and much stiffer properties.
Preparation and Characterization of PVA/Zinc Acetate/ Boron Composite Fibers
Authors: Uslu Ibrahim , Başer Burcu , Yaylı Ahmet , Aksu Mehmet Levent 
Published: August 2014

Abstract The objective of this work was to synthesize boron incorporated PVA/Zinc acetate nano precursor composite polymer fibers using electrospinning technique. Produced fibers, are useful reagents in organic synthesis of zinc oxide nano structures which have gained wide interest because of their potential applications in the fabrication of microelectronic devices. Boron incorporated PVA/Zinc acetate not only improve the electrical properties of ZnO films but also has an influence on the crystal structure of ZnO films. The fibers were measured and characterized by conductiometer (with four-point probe), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The formation of boron incorporated PVA/Zinc acetate hybrid polymer was confirmed by FT-IR spectra. SEM micrographs clearly reveal that there are random-growth oriented fibers on aluminum foil with diameters ranging from 0.5 to 1 μm. According to the TGA analysis decomposition of zinc acetate from the PVA chain was observed around 273 °C, 368 °C and 447 °C. Boron incorporated PVA/Zinc acetate nano composite polymer fibers have been successfully synthesized for the first time using electrospinning technique and characterized in detail as precursor material for ZnO. Electrospinning process has been a widely used, simple and versatile method and in future may be used for large-scale preparation of nanofibers of ZnO.
Modeling of Nonlinear Viscoelastic Creep of Polycarbonate
Authors: Luo Wenbo , Jazouli Said , Vu-Khanh Toan 
Published: August 2014

AbstractThe creep behavior of a commercial grade polycarbonate was investigated in this study. 10 different constant stresses ranging from 8 MPa to 50 MPa were applied to the specimen, and the resultant creep strains were measured at room temperature. It was found that the creep could be modeled linearly below 15 MPa, and nonlinearly above 15 MPa. Different nonlinear viscoelastic models have been briefly reviewed and used to fit the test data. It is shown that the Findley model is a special case of the Schapery model, and both the Findley model and the simplified multiple integral representation are suitable for properly describing the creep behavior of the polycarbonate investigated in this paper; however, the Findley model fit the data better than the simplified multiple integral with three terms.
Zwitterionic Polyelectrolytes: A Review
Authors: Singh Paresh Kumar , Singh Vinay Kumar , Singh Meenakshi 
Published: August 2014

AbstractRecent progress in the field of zwitterionic polyelectrolytes is reviewed. This class of polyelectrolytes is only five decades old, since the first synthesis was in 1952. Polycarboxybetaines, polysulfobetaines, polyphosphobetaines and a few more zwitterionic materials compose this class of polymers. In the current search for ‘biomimicking’ materials, this class is particularly important. The responsive properties of polyzwitterions are specific, sensitive and instantaneous to a wide variety of external stimuli, which has been reviewed in this article. The synthesis of polyampholytes and polybetaines (homopolymers, copolymers, block polymers) are reviewed. The exploitation of such materials in solid state conducting materials, chromatographic materials and other applications has been incorporated. The extensive discussion on solution properties, antipolyelectrolytic characteristics and influence of varying class of electrolytes has been qualitative as well as quantitative providing an insight into the importance and relevance of such materials, the block polymers form reversible ‘schizophrenic’ micelles also.
Characterization of Genipin Crosslinked Hydrogels Composed of Chitosan and Partially Hydrolyzed Poly(vinyl alcohol)
Authors: Nand Ashveen V. , Rohindra David R. , Khurma Jagjit R. 
Published: August 2014

AbstractChitosan and 80 % hydrolyzed poly(vinyl alcohol) (PVA) were used to prepare semi-interpenetrating networks of varying ratios of the constituents. The hydrogels were crosslinked using genipin, a naturally occurring nontoxic crosslinking agent. The swelling behavior of these hydrogels was studied in deionized water at 25, 35 and 45 °C and in media of different pH at 25 °C. The swelling behavior of the gels was found to be dependent on temperature, pH of the medium and the amount of PVA present in the gel. States of water in the hydrogels swollen at 25 °C and pH 7 were determined using Differential Scanning Calorimetry (DSC). The amount of freezing water in the swollen hydrogels increased whereas the amount of nonfreezing bound water decreased with the increase in PVA concentration in the gels. The gelation behaviour of the pregel solutions were also studied.
A Novel pH and Thermo-sensitive N,O-Carboxymethyl Chitosan-graft-Poly(N-isopropylacrylamide) Hydrogel for Controlled Drug Delivery
Authors: Prabaharan M. , Mano J. F. 
Published: August 2014

Abstract A novel kind of thermo and pH-responsive hydrogels was prepared by reacting N,O-carboxymethyl chitosan (NOCC) with amino-telechelic poly(Nisopropylacrylamide) (PNIPAAm-NH2) as a drug delivery carrier. The hydrogels were characterized by FT-IR and 1H-NMR techniques. The phase transition behavior of the hydrogels was found to be dependent on the NOCC/PNIPAAm-NH2 weight ratio and pH value of the medium. The hydrogels with a higher content of PNIPAAm showed a definite phase transition at 32 °C as it occurs in pure PNIPAAm. For the release study, NOCC-g-PNIPAAm beads were prepared using glutaraldehyde (GA) as a crosslinking agent. The swelling ratio of the beads was higher in pH 2.1 than pH 7.4. Moreover, the swelling ratio of the beads decreased with the increase in PNIPAAm content of the beads. The release profile of NOCCg- PNIPAAm beads showed a slower and controlled release of the entrapped ketoprofen, and found that the release behaviour was influenced by both the pH and temperature of the medium. It is expected that these smart hydrogels may be useful to develop drug delivery systems with improved drug loading capacity and controlled release behaviour.
Preparation of fluorescent poly(methylmethacrylate) nano capsules via internal phase separation
Authors: Lv Hui , Lin Quan , Yao Tongjie , Zhang Kai , Zhang Junhu , Yang Bai 
Published: August 2014

AbstractFluorescent nanocapsules containing Eu3+ complex are prepared by the internal phase separation of poly(methylmethacrylate) (PMMA) within the droplets of oil/water nano-emulsion. The nanocapsules give bright red emission excited by UV irradiation and possess stable fluorescence properties. Their fluorescence intensity is primarily influenced by the emulsifier concentration. It is significant that the fluorescence of the nanocapsules is nearly pH-independent and can be kept for a long time in a wide pH range. In contrast, the fluorescence of Eu3+ complex is easily quenched in acidic or alkalic medium. The mean nanocapsule size is tunable with the concentration and the mode of emulsifier addition. As soft templates, oil cores have potential applications for the incorporation of functional components or drugs.
Plasma Polymerization of Amines and Acetone: Functionalized Surfaces for Microarray Applications
Authors: Jehle Heinrich , Kranewitter Wolfgang 
Published: August 2014

AbstractPlasma polymerization (PP) afforded amine as well as carbonyl containing films which are suitable for use in microarray analysis. The polymerization process with acetone (AC), ethylenediamine (EDA) and diethylamine (DEA) has to be performed in the presence of argon as a carrier gas to be successful. Different activation steps of the polymer based support yield surfaces which differ significantly in their elemental composition after the PP step. Angle dependent XPS proves a take off angle dependence of the carbonyl PP film in contrast to a homogeneous PP film for amine functionalized PP layers while microarray experiments have been successful for both functional films.
Modification of Polymeric Materials via Surface-Initiated Controlled/”Living” Radical Polymerization
Authors: Liu Peng 
Published: August 2014

AbstractModification of polymeric materials has been a significant issue over last two decades in many fields of application. Among modification techniques developed to date, surface grafting has emerged as a simple, useful, and versatile approach to improve surface properties of polymers for a wide variety of applications. The synthesis of tethered block copolymer brushes via the use of controlled/”living” free radical polymerization techniques presents many significant advantages over traditional free radical polymerization techniques. This review surveys recent literature on polymer surfaces with graft chains, mainly focusing on grafting methods such as surface-initiated controlled/”living” free radical polymerization via atom transfer radical polymerization (ATRP), nitroxide-mediated radical polymerization (NMRP), reversible addition fragmentation transfer (RAFT) polymerization and iniferter techniques.
Effects of chemical structure on the electrical properties of some polymers with imidic structure
Authors: Cosutchi Andreea Irina , Hulubei Camelia , Buda Manuela , Botila Toni , Ioan Silvia 
Published: August 2014

AbstractThe electrical properties of two types of imidic polymers, i.e. copolymaleimides containing azobenzene groups and epiclon-based polyimides with their corresponding poly(amic acid)s, have been investigated. The dielectric constant and electrical conductance were experimentally measured over the 1-100 KHz frequency range. Also, the dielectric constants for all samples were determined from the experimentally and theoretically evaluated refractive indices at optical frequencies, when Maxwell’s relationship can be applied. From the currentvoltage characteristic I(U), electrical resistance can be determined, providing information on the relationship between the nature of the material and its electric properties. The obtained values show that epiclon-based polyimides and copolymaleimides present higher electrical resistivity than the poly(amic acid)s. The dissipation factor was evaluated, revealing low energy loss under the form of heat in the studied dielectrics. These results show that these polymeric materials are good insulators, which recommends them for microelectronic applications.
Synthesis of resin I: salicylic acid, hexamethylene diamine and formaldehyde and its ion-exchange properties
Authors: Masram Dhanraj.T. , Kariya Kiran.P. , Bhave Narayan.S. 
Published: August 2014

AbstractThe terpolymer resin salicylic acid-hexamethylenediamine-formaldehyde (SHMF) was synthesized by the condensation of salicylic acid and hexamethylenediamine with formaldehyde in the presence of a hydrochloric acid catalyst. The number average molecular weight of the resin was determined by non-aqueous conductometric titration. Terpolymer resin was characterized by elemental analysis, infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and UV- Visible spectral studies. Chelation ion exchange properties have also been studied for Fe3+, Cu2+, Ni2+, Co2+, Zn2+, Cd2+ and Pb2+ions employing a batch equilibrium method. It was employed to study the selectivity of metal ion uptake involving the measurements of distribution of a given metal ion between the polymer sample and a solution containing the metal ion. The study was carried out over wide pH range and in the media of various ionic strengths. The terpolymer showed a higher selectivity for Fe3+, Cu2+ and Ni 2+ions than for Co2+, Zn2+, Cd2+, and Pb2+ ions.
Preparation and characterization of styrene-methyl methacrylate In deproteinized natural rubber latex (SMMADPNR)
Authors: Man Siti Hajjar Che , Hashim Azanam S. , Akil Hazizan Md. 
Published: August 2014

AbstractThe graft polymerization of Styrene and Methyl methacrylate (MMA) onto deproteinized natural rubber latex (DPNR) was carried out using ammonium peroxy disulfate (N2H8O8S2) as an initiator. The suitable reaction conditions based on the higher monomer conversion was determined. The degree of grafting and the copolymers composition of the resultant SMMA-DPNR were obtained using 1H NMR Spectroscopy. As expected, composition of styrene in DPNR was higher than that of MMA due to the higher reactivity ratio of styrene monomer as compared to MMA monomer and the structure of the NR backbone. The mechanism of seeded emulsion polymerization leading to graft copolymer of styrene and MMA onto NR was studied and elucidated.
Investigation of thermal, rheological and mechanical properties of interfacially modified PP/mica composites
Authors: Khonakdar Hossein Ali , Morshedian Jalil , Yazdani Hamid 
Published: August 2014

AbstractComposites of polypropylene (PP) with mica powder were produced by melt mixing in an internal mixer. In this research work, the effect of the interfacial modifiers such as maleated polypropylene (MAPP) and silane coupling agent, that encapsulated the mica (treated mica), on the mechanical, thermal and rheological characteristics of mica-filled PP have been investigated. In the literature, it can be seen that increasing mica powder leads to reduced crystallinity of PP. But our results show that reduction in crystallinity is noticeably lesser when interfacial modifier such as MAPP is used. Also, the results of thermogravimetric analysis test showed that MAPP and treated mica caused improvement of heat resistance of the composites. The degradation shifted to higher temperatures which could be due to adhesion between PP and mica powder. The mica powder when added to PP increased the viscosity considerably. However treated mica/PP composite in molten state had noticeably less viscosity in comparison with that of neat micafilled PP and thus having better moldability. Results of decrease in elongation at break with filler content have been compared with predictions of Nielsen’s model and Mitsuishi equation.