1,721,002 research outputs found
Two Component Silyl-Terminated Polyether/Epoxy Resin Systems Mechanical and Rheological Properties
No full textTwo component model systems from Silyl-terminated polyether (SAX 520) and epoxy resin (D.E.R. 331) can produce higher mechanical properties than each system individually. This work is dedicated to explore two components (SAX 520/D.E.R. 331) systems and represent their benefits comparing to neat SAX 520 based system. Work shows that compositions with epoxy resin not only improves material mechanical properties, but also its stability after aging, workability time and adhesion on various substrates.</jats:p
Research of Potential Catalysts for Two-Component Silyl-Terminated Prepolymer/Epoxy Resin Adhesives
No full textThe current research is devoted to the research of potential catalysts for the two-component silyl-terminated prepolymer/epoxy resin system. The catalyst system must catalyze the prepolymer of the opposite component while not curing the prepolymer in the component in which the catalyst is located. Mechanical and rheological characterization of the adhesive was performed. The results of the investigation showed that certain alternative catalyst systems, which are less toxic, may be used instead of traditional catalysts for individual systems. Two-component systems, obtained by using these catalysts systems, cure in an acceptable time scale and demonstrate relatively high tensile strength and deformation values
Secondary Insulating Glass Sealant from Synthesized Mercapto Terminated Prepolymer Based on Polyether Polyol and Castor Oil
No full textThiokol is one of the oldest and the most expensive prepolymers which also is used for insulating glass application. One of potential alternatives is modified polyether polyol, but it has poor ultraviolet light stability. This work is dedicated to synthesized alternative prepolymers and development of two component systems for insulating glass sealant application. By subjecting these particular systems to temperature, water and ultraviolet light resistance tests, it is concluded that in respect to water and UV-light resistance the systems of modified prepolymers are even better than the system with thiokol prepolymer.</jats:p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The Properties of Mesh Reinforced Nonwoven Composites
No full textTo create the heat-bonded geotextile with desirable properties, the mix of fibres (hemp, recycled polyethylene terephthalate and polypropylene fibres) for nonwoven webs formation and additional polypropylene reinforcing mesh are used. The results of the study on the influence of the reinforcing mesh on the properties of nonwoven composites (NWCs) are presented. Mechanical properties, water penetration and air permeability of the thermoplastic mesh reinforced NWCs depend on the hemp fibre pre-treatment time, mass per unit area and thickness of the used web and location of the reinforcing mesh. Obtained results allow concluding that mechanical as well as water penetration characteristics of the produced heat-bonded geotextiles are higher, while air permeability is comparable to the properties of the commercial prototype.</jats:p
Mechanical and Heat Shrinkable Properties of Electron Beam Irradiated Polypropylene With Bisphenol A Dimethacrylate Crosslinker
No full textEffect of Algerian Halloysite on the Mechanical and Thermal Properties of Starch-Grafted-Polyethylene Nanocomposites
No full textThis paper deals with the characterization of the physico-mechanical properties of starch-grafted-polyethylene (Starch-g-PE)/unmodified Algerian halloysite nanotubes (HNT) nanocomposites prepared by melt compounding. The nanoclay was incorporated at various filler contents, i.e., 1.5, 3 and 5 wt%. Rheological and tensile properties of the nanocomposites were evaluated by different techniques and the results obtained are compared with those of virgin Starch-g-PE matrix. The study shows a decrease in melt flow index (MFI) values upon increasing the HNT content, which indicates a restriction in the polymer chains mobility due to the confinement effect of HNT. Further, a tensile strength is also improved.</jats:p
Mercerization of Agricultural Waste: Sweet Clover, Buckwheat, and Rapeseed Straws
No full textThis research presents the alkali treatment effect on three types of agricultural residues: sweet clover (SCS), buckwheat (BS), and rapeseed straws (RS). The aim of the study was to find the optimal treatment conditions for each straw type, and to assess the potential of sweet clover straw as reinforcement for polymer composites in comparison to buckwheat and rapeseed. The straws were ground and treated for 15, 30, and 60 min using NaOH at concentrations of 2, 5, and 10%. To investigate the treatment results on the SCS, BS, and RS fibers, Fourier transform infrared spectroscopy, scanning electron microscopy, optical microscope, X-ray diffraction, and thermogravimetric analysis were used. Results indicate that the optimal room-temperature alkaline-treatment conditions of SCS fibers were the same as those for RS treated with 2% NaOH solution for 30 min. These conditions were milder in comparison to those used for the treatment of BS: 60 min in a 5% NaOH solution. During the treatment, noncellulosic substances were largely removed, and the aspect ratio of the fibers was increased, and the destruction temperature, crystallinity, and morphology were also affected. Consequently, SCS has promising potential for use in polymer composites
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