pinecone/core-2020-05-10-deduplication huggingface dataset:
Effect of various efficient vulcanization cure systems on the compression set of a nitrile rubber filled with different fillers

This is the peer reviewed version of the following article: OSTAD-MOVAHED, S., ANSARIFAR, A. and MIRZAIE, F., 2015. Effect of various efficient vulcanization cure systems on the compression set of a nitrile rubber filled with different fillers. Journal of Applied Polymer Science, 132 (8), DOI: 10.1002/APP.41512, which has been published in final form at: https://doi.org/10.1002/app.41512. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Effect of various efficient vulcanization (EV) sulfur cure systems on the compression set of a nitrile rubber filled with carbon black and silica/silane fillers was examined. The cure systems had different amounts of thiuram and sulfenamide accelerators and elemental sulfur, whilst the loading of zinc oxide and stearic acid activators was kept constant. The fillers had surface areas from 35 to 175 m 2 /g. In this study, the lowest compression set was measured for the rubber filled with carbon black with 78 m 2 /g surface area, which was cured with an EV cure system made of a small amount of elemental sulfur and large amounts of the two accelerators. Interestingly, a small change in the amount of elemental sulfur had a bigger effect on the compression set than did large changes in the loading of the accelerators in the cure system. Among the fillers, carbon black caused less compression set of the rubber vulcanizate than the silica/silane system did
Formation of continuous dense polymer layer at the surface of hollow fiber using a photografting process

The main objective of this study is to develop a new formula for a diet mayonnaise-like sauce without cholesterol. Emulsifying power is provided by the use of soy lecithin and the total fat content was limited to 16%. Droplet size measurement of employed mayonnaise samples at different times show that the largest diameter of fat does not exceed 18.5 µm with a yield stress of 56.1 Pa. Results of stability to centrifugation reveal that the absence of the supernatant oily layer ensures the stability of the emulsion. Using the experimental design method, the number of trials can be limited to a number of 16 experiments, and best formulation of the mayonnaise (without cholesterol) was obtained
Electrical conductivity and tensile properties of block-copolymer-wrapped single-walled carbon nanotube / poly(methyl methacrylate) composites

Poly(methyl methacrylate) (PMMA) composites containing raw or purified single-walled carbon nanotubes (SWCNTs) are prepared by in-situ polymerization and solution processing. The SWCNTs are purified by centrifugation in a Pluronic surfactant, which consists of polyethyleneoxide and polypropyleneoxide blocks. Both the effects of SWCNT purity and non-covalent functionalization with Pluronic are evaluated. Electrical conductivity of PMMA increases by 7 orders of magnitude upon the integration of raw or purified SWCNTs. The best electrical properties are measured for composites made of purified SWCNTs and prepared by in-situ polymerization. Strains at fracture of the SWCNT/PMMA composites are nearly identical to those of the neat matrix. A certain decrease in the work to fracture is measured, particularly for composites containing purified SWCNTs (-31.6 %). Fractography and Raman maps indicate that SWCNT dispersion in the PMMA matrix improves upon the direct addition of Pluronic, while dispersion becomes more difficult in the case of purified SWCNTs.This work was funded by the Spanish MINECO under the projects TEC2010-15736, MAT2010-16175 (CICYT), CTQ2006-02330 and PRI-PIBAR-2011-1, and the Government of Aragon (DGA) and the European Social Fund (ESF) under Project DGA-ESF-T66 CNN. C. Ruano acknowledges MINECO for her PhD grant BES2007-17250.Peer reviewe
Impact of Oxygen Transport Properties on the Kinetic Modeling of Polypropylene Thermal Oxidation. II. Effect of Oxygen Diffusivity

The kinetic model, established in a previous article (François-Heude et al., J. Appl. Polym. Sci., in press) to predict the homogeneous oxidation in iPP films typically thinner than 100 µm, is now extended to simulate the oxidation profiles in thicker plates by coupling the oxygen diffusion and its consumption by the chemical reactions. In this perspective, oxygen transport properties (namely oxygen solubility, diffusivity, and permeability) are measured by permeametry on a reference iPP. These values are compared with an exhaustive compilation of literature data to evaluate their variability among the whole iPP family, which one has been reasonably ascribed to initial differences in polymer morphology, but also to evaluate their consistency, especially their temperature dependence between 20 and 140°C. Failing to simulate oxidation profiles, the kinetic model is then used as an inverse resolution method for estimating more satisfactory values of oxygen transport properties. It is thus evidenced that the crystallinity changes induced by thermal oxidation largely explains the dramatic decrease in oxygen penetration toward the sample core just after the induction period. A strategy aimed for introducing the relationship between the polymer crystalline morphology and oxygen transport properties into the kinetic model is given in the graphical abstract, although the effect of polymer polarity remains to be established prior to this implementation
Thiol-norbornene photo-click hydrogels for tissue engineering applications.

Thiol-norbornene (thiol-ene) photo-click hydrogels have emerged as a diverse material system for tissue engineering applications. These hydrogels are cross-linked through light mediated orthogonal reactions between multi-functional norbornene-modified macromers (e.g., poly(ethylene glycol), hyaluronic acid, gelatin) and sulfhydryl-containing linkers (e.g., dithiothreitol, PEG-dithiol, bis-cysteine peptides) using low concentration of photoinitiator. The gelation of thiol-norbornene hydrogels can be initiated by long-wave UV light or visible light without additional co-initiator or co-monomer. The cross-linking and degradation behaviors of thiol-norbornene hydrogels are controlled through material selections, whereas the biophysical and biochemical properties of the gels are easily and independently tuned owing to the orthogonal reactivity between norbornene and thiol moieties. Uniquely, the cross-linking of step-growth thiol-norbornene hydrogels is not oxygen-inhibited, therefore the gelation is much faster and highly cytocompatible compared with chain-growth polymerized hydrogels using similar gelation conditions. These hydrogels have been prepared as tunable substrates for 2D cell culture, as microgels or bulk gels for affinity-based or protease-sensitive drug delivery, and as scaffolds for 3D cell culture. Reports from different laboratories have demonstrated the broad utility of thiol-norbornene hydrogels in tissue engineering and regenerative medicine applications, including valvular and vascular tissue engineering, liver and pancreas-related tissue engineering, neural regeneration, musculoskeletal (bone and cartilage) tissue regeneration, stem cell culture and differentiation, as well as cancer cell biology. This article provides an up-to-date overview on thiol-norbornene hydrogel cross-linking and degradation mechanisms, tunable material properties, as well as the use of thiol-norbornene hydrogels in drug delivery and tissue engineering applications
Modification of microfiltration membranes by hydrogel impregnation for pDNA purification

The huge efforts for the achievement of highly purified biomolecules are growing every day. A great number of efficient techniques, such as chromatography, are already available in laboratory for separation processes. However, membrane-based technologies are the best match to assure simplicity, efficiency and easy scale-up procedures. Herein we report the modification of a commercial microfiltration membrane for plasmid DNA purification by agarose gel impregnation. The membrane was characterized by SEM,
ATR-FTIR, EDS, contact angle, and porosity measurements. Additionally, the membrane pore radius was estimated from observed
rejections of different proteins and with that information the rejection of a 6050 bp plasmid DNA (pDNA) molecule was estimated for different values of flux using a theoretical model of large flexible molecules in membranes with parallel cylindrical pores, which is applicable to pDNA ultrafiltration in conventional membranes, as recently shown in the literature. The experimental results show that the modified membrane has higher pDNA rejections than the predicted by the model, suggesting that the different type of porous structure that a hydrogel has, may have a positive effect on pDNA rejections as compared to other biomolecules with more rigid structures, making this type of modified membranes potential better candidates to be used for the selective recovery of pDNA in this type of bioprocesses.Fundação para a Ciência e a Tecnologia (FCT), Portugal, for the grant awarded to António Morão (SFRH/BPD/88838/2012). Pest-C/SAU/UI0709/2011 and Pest-OE/SAU/UI0709/201
Oxidative solution polymerization of aniline hydrochloride onto electrospun nanofibers mats of polylactic acid: Preparation method and characterization

In this work, we present the preparation of polylactic acid (PLLA)/polyaniline (PANI) conductive composite nanofibers mats. They are prepared by bulk oxidative solution polymerization of PANI onto electrospun non-woven fibers mats of PLLA. The PANI ratio in the composite is about 70%w/w. Scanning electron microscopy (SEM) shows that PLLA nanofibers are randomly oriented, beads free with diameters of 186 ± 85 nm, The PLLA/PANI composite nanofibers diameter values are 518 ± 128 nm with a good adherence between PANI and PLLA nanofibers. DSC and XRD measurements reveal an amorphous structure of the electrospun PLLA fibers due to the rapid evaporization of the solvent. FTIR and UV-vis spectra reflect good mutual interactions between PANI and PLLA chains. The DC-conductivities (σ=0.07-0.13-S.cm-1) far better than other published ones for similar composites prepared by bulk oxidative solution polymerization of PANI onto other electrospun nanofiber mats or with electrospun nanofibers from a solution mixture of PLLA and PANI
Synthesis and characterization of maleated rosin‐modified fluorosilicone resin and its fluorosilicone rubber

Imide‐containing vinyl fluorosilicone resin (MR‐VFS) was synthesized from maleated rosin (MR). And then, with MR‐VFS as a new polar cross‐linking agent in a heat curable fluorosilicone rubber composition, a series of maleated rosin‐modified fluorosilicone rubbers (MR‐FSR) were obtained. The effects of MR‐VFS on the mechanical properties, oil resistance, thermal stability, and low‐temperature performance were studied in detail. It was found that MR‐VFS could increase the tearing strength and high‐temperature thermal stability of fluorosilicone rubber. When the MR‐VFS weight content reached to 2 wt %, the tearing strength of MR‐FSR increased by 20.1% compared with that of common fluorosilicone rubber. However, MR‐FSR showed a similar low‐temperature resistance and a little worse oil resistance. The morphological study showed that incorporation of maleated rosin could intensify the microphase separation of fluorosilicone rubber. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41888
Properties and application of polyimide-based composites by blending surface functionalized boron nitride nanoplates

This is the peer reviewed version of the following article: Chen, Y., et al., Properties and application of polyimide-based composites by blending surface functionalized boron nitride nanoplates, Journal of Applied Polymer Science, 132 (16) which has been published in final form at http://dx.doi.org/10.1002/app.41889. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for self-archiving.This is the peer reviewed version of the article which has been published in final form at http://dx.doi.org/10.1002/app.41889. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving
Preparation and characterization of benzoxazine based nanocomposites: comprehensive study in curing kinetics and enhanced thermal stabilities

This is the peer reviewed version of the article which has been published in final form at http://dx.doi.org/10.1002/app.41903 This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Several bisphenol-A benzoxazine (BEN) based nanocomposites incorporated with several polyhedral oligomeric silsesquioxane (POSS), carbon nanotubes (CNTs), and clays, were prepared successfully. The influences of the nanofillers on curing kinetics, network formation, and thermal stability of the BEN were investigated comprehensively. The addition of the nanofillers showed different influence on curing kinetics of BEN. Furthermore, the incorporation of the nanofillers showed good improvement on thermal stability of BEN. An increase of 70 and 336°C at the onset and the half-life decomposition temperature were observed with the addition of 5 wt % 30B clay in nitrogen atmosphere. With the incorporation of 5 wt % POSS, the half-life of decomposition and char yield enhanced by 280°C and 13 wt % in nitrogen atmosphere. For the 4 wt % MWCNT-COOH/BEN nanocomposite, the half-life of decomposition and char yield at 800°C increased by 286°C and 14 wt % in nitrogen atmosphere, respectively
Films made from poly(vinyl alcohol-co-ethylene) and soluble biopolymers isolated from postharvest tomato plant

Blended films were obtained from polyvinyl alcohol‐co‐ethylene (EVOH) with 52 kDa weight average molecular weight (Mw) and three water soluble biopolymers isolated from exhausted tomato plants hydrolysates. Two biopolymers contained mainly polysaccharides and had 27 and 79 kDa Mw, respectively. The third contained mainly lignin‐like C moieties and had 392 kDa MW. The films were fabricated with a biopolymer/EVOH w/w ratio ranging from 0.1 to 0.9. All blends had molecular weight and solubility which were substantially different from the starting materials. They were characterized for the chemical nature, and the thermal, rheological, and mechanical properties. Evidence of a chemical reaction between the biopolymers and EVOH was found. Generally, the films exhibited higher mechanical strength but lower strain at break then the neat EVOH. The best performing blended film was fabricated from the 27 kDa Mw polysaccharide. This contained less than 10% biopolymer. It exhibited 1043 MPa Young's modulus and 70% strain at break against 351 MPa modulus and 86% strain for neat EVOH. The results offer scope for investigating biopolymers sourced from other biowastes to understand more the reasons of the observed effects and exploit their full potential to modify or to replace synthetic polymers
Electrospinning of gelatin fibers using solutions with low acetic acid concentration: effect of solvent composition on both diameter of electrospun fibers and cytotoxicity

Gelatin fibers were prepared by electrospinning of gelatin/acetic acid/water ternary mixtures with the aim of studying the feasibility of fabricating gelatin nanofiber mats at room temperature using an alternative benign solvent by significantly reducing the acetic acid concentration. The results showed that gelatin nanofibers can be optimally electrospun with low acetic acid concentration (25% v/v) combined with gelatin concentrations higher than 300 mg/ml. Both gelatin solutions and electrospun gelatin mats (prepared with different acetic acid aqueous solutions) were analyzed by FTIR and DSC techniques in order to determine the chemical and structure changes\ud
of the polymer. The electrospun gelatin mats fabricated from solutions with low acetic acid content showed some advantages as the maintenance of the decomposition temperature of the pure gelatin (~230ºC) and the reduction of the acid content on electrospun mats, which allowed to reach a cell viability upper than 90% (analyzed by\ud
cell viability test using human dermal fibroblast and embryonic kidney cells). This study has also analyzed the influence of gelatin and acetic acid concentration both on the solution viscosity and the electrospun fiber diameter, obtaining a clear relationship between these parametersPostprint (author’s final draft
Electrical conduction in plasma polymerized thin films of γ-terpinene

Plasma polymerized c-terpinene (pp2GT) thin films are fabricated using RF plasma polymerization. MIM structures are fabricated and using the capacitive structures dielectric properties of the material is studied. The dielectric constant values are found to be in good agreement with those determined from ellipsometric data. At a frequency of 100 kHz, the dielectric constant varies with RF deposition power, from 3.69 (10 W) to 3.24 (75 W). The current density–voltage (J2V) characteristics of pp–GT thin films are investigated as a function of RF deposition power at room temperature to determine the resistivity and DC conduction mechanism of the films. At higher applied voltage region, Schottky conduction is the dominant DC conduction mechanism. The capacitance and the loss tangent are found to be frequency dependent. The conductivity of the pp2GT thin films is found to decrease from 1.39 3 10212 S/cm (10 W) to 1.02 3 10213 S/cm (75 W) and attributed to the change in the chemical composition and structure of the polymer. The breakdown field for pp–GT thin films increases from 1.48 MV/cm (10 W) to 2 MV/cm (75 W). A single broad relaxation peak is observed indicating the contribution of multiple relaxations to the dielectric response for temperature dependent J2V. The distribution of these relaxation times is determined through regularization methods. VC 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42318
Micro-contact reconstruction of adjacent carbon nanotubes in polymer matrix through annealing-Induced relaxation of interfacial residual stress and strain

YesThermoplastic polyurethane (TPU)/multi-walled carbon nanotubes (CNT) nanocomposites were prepared by twin-screw extrusion and micro injection molding. The electrical conductivity of micro injection molded polymer nanocomposites exhibits a low value and uneven distribution in the micromolded samples. Real-time tracing of electrical conductivity was conducted to investigate the post thermal treatment on the electrical conductivity of microinjection molded composites. The results show that postmolding thermal treatment leads to a significant increase in the electrical conductivity by over three orders of magnitude for 5 wt % CNT-filled TPU composites. In-situ Transmission electron microscopy confirms the conductive CNT network does not change at the micron/sub-micron scale during thermal treatment. TEM image analysis by a statistical method was used to determine the spatial distribution of CNT in the sample and showed that the average distance between adjacent CNT reduced slightly at the nanometer scale after postmolding thermal treatment. A new conductive mechanism is proposed to explain the enhancement of electrical conductivity after thermal treatment, i.e. micro-contact reconstruction of adjacent CNT in the polymer matrix through annealing-induced relaxation of interfacial residual stress and strain. Raman spectra and small angle X-ray scattering curve of annealed samples provide supporting evidence for the proposed new conductive mechanism. The electron tunneling model was used to understand the effect of inter-particle distance on the conductivity of polymer composites.Chinese Ministry of Education. Grant Number: 313036; National Natural Science Foundation of China. Grant Number: 51433006Early online publication on 20 May 2015
Influence of new thermoplastic sizing agents on the mechanical behavior of poly(ether ketone ketone)/carbon fiber composites

In this study, unidirectional poly(ether ether ketone)/carbon fiber (CF) composite sheets were elaborated with unsized, epoxy-sized, and thermoplastic-sized CFs by hot-press molding. The thermoplastic sizings that we used were poly(ether imide) (PEI)and poly(ether ketone ketone) oligomer aqueous dispersions. Scanning electron microscopy observation of the composites freeze fractures showed that unlike unsized or epoxy-sized CFs, the thermoplastic sizings improved the interaction between the fibers and the matrix. A comparative study of the mechanical relaxations by dynamic mechanical analysis was carried out on the different composites before and after immersion in kerosene. At low temperature, the PEI sizing had a significant influence on the b relaxation, particularly after kerosene immersion. The thermoplastic sizings did not modify the glass-transition temperature but improved the kerosene resistance on the composites
Active edible films: Current state and future trends

Active edible films represent one of the current and future trends in the development of new polymers for selected applications, particularly food packaging. Some biopolymers show excellent performance as carriers for active compounds extracted from natural sources and are able to be released at a controlled rate to packaged food. In this review we aim to present, in a comprehensive way, the most recent advances and updates in this subject, where much research is currently ongoing and new studies are reported very often. This review focuses on innovative biopolymer matrices, their processing to obtain edible active films, and present and future applications
Printability of elastomer latex for additive manufacturing or 3D printing

This is the peer reviewed version of the article, which has been published in final form at http://dx.doi.org/10.1002/app.42931. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Additive manufacturing, sometimes referred to as 3D printing is a new, rapidly developing technology which has the potential to revolutionize fabrication of certain high value, complex products. Until now conventional elastomers have not been widely used in the additive manufacturing process. The goal of our work was to determine the feasibility of additive manufacturing using ink jet printing of elastomeric latex materials. Particle size, viscosity, and surface tension were measured for five different latex materials—poly(2-chloro-1,3-butadiene), carboxylated styrene-butadiene rubber, carboxylated butadiene-acrylonitrile copolymer, natural rubber, and prevulcanized natural rubber. The XSBR latex was predicted as the one most likely to be printable. Printing trials carried out with the XSBR as the ink proved it to be printable, although technical problems of agglomeration and print head clogging need to be addressed and both the material and process need to be optimized for consistent printing to be achieved