Resulting Composites (resulting + composite)

Distribution by Scientific Domains


Selected Abstracts


Continuous surface modification process with ultraviolet/ozone for improving interfacial adhesion of poly(ethylene terephthalate)/epoxy composites

POLYMER COMPOSITES, Issue 5 2006
Paisan Khanchaitit
This study proposed a continuous UV/ozone surface modification process for the production of polymeric fiber-reinforced polymer composite. A gas phase photoreactor using the conventional low-pressure mercury UV lamps and the economically made ozone generators were designed and constructed. Poly(ethylene terephthalate) (PET) fibers and epoxy resin were chosen as a reinforcement and a matrix, respectively. The synergistic effects of UV and various gas species (nitrogen, air, oxygen, air/ozone, and oxygen/ozone) exposure as well as the effects of exposure time, i.e., 2, 5, and 10 min, on the morphology and chemistry of PET-fiber surfaces were investigated by using a scanning electron microscope coupled with energy dispersive x-ray analysis (SEM/EDX). The tensile testing and analysis of fractography of the resulted composites were performed to evaluate the effectiveness of the process. The SEM/EDX results showed that the effects of the treatment were dependent on both the concentration of reactive species present in the gases and the exposure time. The PET fibers treated under UV/O2 + O3 exposure for 5 min yielded the resulting composite with the highest tensile strength value. Under this condition, the tensile strength of the composite can be increased up to 63% in comparison with that of the untreated PET fiber/epoxy composite. The results are of interest for application as an in-line surface modification for composite productions. POLYM. COMPOS., 27:484,490, 2006. © 2006 Society of Plastics Engineers [source]


Synthesis and characterization of poly(butylene succinate)/epoxy group functionalized organoclay

POLYMER INTERNATIONAL, Issue 9 2007
Guang-Xin Chen
Abstract Poly(butylene succinate) (PBS)/clay nanocomposites were prepared by condensation polymerization of 1,4-butanediol and succinic acid in the presence of an organoclay containing epoxy groups (TFC) and titanium(IV) butoxide as a catalyst. The intercalation and exfoliation of the clay layers in the resulting composite were examined using X-ray scattering and transmission electron microscopy. The role of the epoxy groups of TFC was investigated for the improvement of the morphology of the composites. The silicate layers in the composite were exfoliated to a greater extent as the epoxy content of TFC was increased from 0.245 to 0.359 mmol g,1, while only intercalated morphology was obtained when no epoxy was present. The improved morphologies were attributed to the enhanced interfacial interactions between PBS and TFC through a chemical reaction of the epoxy groups with the end groups of the PBS. The nonisothermal crystallization process of the composites as well as that of neat PBS is well represented by the Avrami equation as modified by Jeziorny [Jeziorny A, Polymer19:1142 (1978)]. The crystallization of the composite took place faster as the epoxy content of the clay increased, due to the more effective nucleation of the well-dispersed TFC layers. Copyright © 2007 Society of Chemical Industry [source]


A simple approach toward low-dielectric polyimide nanocomposites: Blending the polyimide precursor with a fluorinated polyhedral oligomeric silsesquioxane

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2008
Yun-Sheng Ye
Abstract This article describes a new and simple method for preparing polyimide nanocomposites that have very low dielectric constants and good thermal properties: simply through blending the polyimide precursor with a fluorinated polyhedral oligomeric silsesquioxane derivative, octakis(dimethylsiloxyhexafluoropropyl) silsesquioxane (OF). The low polarizability of OF is compatible with polyimide matrices, such that it can improve the dispersion and free volume of the resulting composites. Together, the higher free volume and lower polarizability of OF are responsible for the lower dielectric constants of the PI-OF nanocomposites. This simple method for enhancing the properties of polyimides might have potential applicability in the electronics industry. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6296,6304, 2008 [source]


Effect of processing technique on the dispersion of carbon nanotubes within polypropylene carbon nanotube-composites and its effect on their mechanical properties

POLYMER COMPOSITES, Issue 5 2010
Amal M.K. Esawi
Carbon nanotube-reinforced polymer composites are being investigated as promising new materials having enhanced physical and mechanical properties. With regards to mechanical behavior, the enhancements reported thus far by researchers are lower than the theoretical predictions. One of the key requirements to attaining enhanced behavior is a uniform dispersion of the nanotubes within the polymer matrix. Although solvent mixing has been used extensively, there are concerns that any remaining solvent within the composite may degrade its mechanical properties. In this work, a comparison is carried out between solvent and "solvent-free" dry mixing for dispersing multiwall carbon nanotubes in polypropylene before further melt mixing by extrusion. Various weight fractions of carbon nanotubes (CNTs) are added to the polymer and their effect on the mechanical properties of the resulting composites is investigated. Enhancements in yield strength, hardness, and Young's modulus when compared with the neat polymer, processed under similar conditions, are observed. Differences in mechanical properties and strain as a function of the processing technique (solvent or dry) are also clearly noted. In addition, different trends of enhancement of mechanical properties for the solvent and dry-mixed extrudates are observed. Dry mixing produces composites with the highest yield strength, hardness, and modulus at 0.5 wt% CNT, whereas solvent mixing produces the highest mechanical properties at CNT contents of 1 wt%. It is believed that this difference is primarily dependent on the dispersion of CNTs within the polymer matrix which is influenced by the processing technique. Field emission scanning electron microscopy analysis shows the presence of clusters in large wt% CNT samples produced by dry mixing. Samples produced by solvent mixing are found to contain homogeneously distributed CNTs at all CNT wt fractions. CNT pull-out is observed and may explain the limited enhancement in mechanical properties. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers [source]


The effect of polyoxypropylene-montmorillonite intercalates on polymethylmethacrylate

POLYMER COMPOSITES, Issue 1 2009
Nehal Salahuddin
Polymethylmethacrylate (PMMA)-layered silicate nanocomposites have been prepared by in situ polymerization of commercial type of methylmethacrylate monomer (MMA), for denture base material, into organoclay. Organoclay was prepared through an ion exchange process between sodium cations in montmorillonite and NH3+ groups in polyethertriamine hydrochloride and polyoxypropylene triamine hydrochloride with different molecular weight (5000, 440). X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) have been used to investigate the structure of the resulting composites. Both intercalated and exfoliated nanocomposites were obtained depending on the type and amount of organoclay. The thermal decomposition temperatures of the nanocomposites were found to be higher than that of pristine polymer. PMMA was strongly fixed to inorganic surfaces, due to cooperative formation of electrostatic bonding between NH3+ group and negatively charged surface of layered silicate and amide linkage between PMMA and polyethertriamine or polyoxypropylene triamine. The effect of the organoclay on the hardness, toughness, tensile stress, and elongation at break of the polymer was studied and was compared with pristine polymer. The hardness and Izod impact strength of PMMA-organoclay nanocomposites were enhanced with the inclusion of clay. Tensile properties appear to be enhanced at certain organoclay content. However, the water absorption is slightly higher than the pristine PMMA. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source]


Preparation of polyaniline,polypyrrole composite sub-micro fibers via interfacial polymerization

POLYMER COMPOSITES, Issue 1 2008
Shuangxi Xing
Polyaniline,polypyrrole (PANI,PPy) composite sub-micro fibers were prepared via interfacial polymerization of aniline and pyrrole using ammonium persulfate (APS) as oxidant. Carbon tetrachloride was used as the organic solvent to dissolve the monomers and APS was dissolved in HCl aqueous solution. The reaction was carried out at the interface formed by the two above solutions. Scanning electron microscopy, Fourier transformation infrared spectra and differential thermal analysis were conducted to characterize the morphology, structure and thermostability of the resulting composites. Dodecyl benzene sulfonic acid was also used as medium to make comparison with that using HCl in the reaction system. The guidance of the formation of the PANI nanofibers at the first step and the interaction between PANI and PPy were considered as the drive forces to yield the composite sub-micro fibers. POLYM. COMPOS., 29:22,26, 2008. © 2007 Society of Plastics Engineers [source]


Carbon Nanotube and Gold-Based Materials: A Symbiosis

CHEMISTRY - A EUROPEAN JOURNAL, Issue 6 2010
Rajpal Singh Dr.
Abstract Carbon nanotubes constitute a novel class of nanomaterials with potential applications in many areas. The attachment of metal nanoparticles to carbon nanotubes is new way to obtain novel hybrid materials with interesting properties for various applications such as catalysts and gas sensors as well as electronic and magnetic devices. Their unique properties such as excellent electronic properties, a good chemical stability, and a large surface area make carbon nanotubes very useful as a support for gold nanoparticles in many potential applications, ranging from advanced catalytic systems through very sensitive electrochemical sensors and biosensors to highly efficient fuel cells. Here we give an overview on the recent progress in this area by exploring the various synthesis approaches and types of assemblies, in which nanotubes can be decorated with gold nanoparticles and explore the diverse applications of the resulting composites. [source]