Search results for "fiber"
showing 10 items of 2343 documents
Growth of fibrous aggregates of silica nanoparticles: Fibre growth by mimicking the biogenic silica patterning processes
2009
We describe the self-assembly of discrete SiO2 nanofibers via grafting of silicatein side chains to a polymer backbone. The covalent binding of silicatein to the backbone of the polymer is based on the affinity of the nitrilotriacetic acid (NTA) side chain, which serves as a ligand for the immobilization of His-tagged silicatein. The surface charge and the bulkiness of the protein moieties prevent the entropically favoured coil formation of the polymer and force it to adopt an open chain structure after hydrolysis of the silica precursors. The probes were characterized by scanning force microscopy (SFM) and optical light microscopy. Surface complexation of the resulting silica nanoparticles…
Synthesis of Microporous Carbon Nanofibers and Nanotubes from Conjugated Polymer Network and Evaluation in Electrochemical Capacitor
2009
One-dimensional fibers and tubes are constructed through the oriented carbon-carbon cross-linking reactions towards rigid conjugated polymer networks. As the result, a template-free and one-step synthesis of CNTs and CNFs is achieved through a simple carbonization of the as-formed carbon-rich tubular and fiberlike polyphenylene precursors under argon. Microporous CNTs and CNFs with a surface area up to 900 m2 g–1 are obtained, together with HR-TEM characterizations indicating the formation of intrinsic microporous structure in these rigid carbon-rich networks. The primary electrochemical experiments reveal their promising applications as advanced electrodes in electrochemical double-layered…
Preparation and mechanical characterization of polycaprolactone/graphene oxide biocomposite nanofibers
2016
Biocomposite nanofiber scaffolds of polycaprolactone (PCL) filled with graphene oxide (GO) were prepared using electrospinning technology. Morphological and mechanical properties of the scaffolds were characterized in dry and wet environment. The results showed that the successful incorporation of GO nanosheets into PCL polymer nanofibers improved their mechanical properties. Furthermore it was demonstrated the higher performance achieved when GO is filled at low concentration in the nanofibers.
Prediction method of electrical conductivity of nano-modified glass fibre reinforced plastics
2019
Glass fibre reinforced plastics (GFRP) is non-conductive construction material, however with carbon nanotubes (CNT) modifying it can get additional functionality due to its gained electrical conductivity. Main aim of the study is to check functionality of the prediction method of electrical conductivity of GFRP with nano-modified epoxy matrix using structural approach. GFRP composites under investigation were based on unidirectional (UD) Glass fiber and two matrixes modified with carbon nanotubes. Electrical conductivity of epoxy resin modified by CNT (concentrations < 1%) was modelled using structural approach. Electrical conductivity of unidirectional GFRP layer was measured experimentall…
Compatibilization of blends of polyethylene with a semirigid liquid crystalline polymer by PE-g-LCP copolymers
1997
The blends of thermoplastics with liquid crystalline polymers show, in general, poor properties because of the lack of adherence between the two phases. The use of ad hoc synthesized copolymers containing the monomer units of the two polymers has been recently considered by some of us for blend compatibilization, and the results appear promising. In this work, new PE-g-LCP copolymers, prepared either by the synthesis of the LCP in the presence of a functionalized PE, or by reactive blending of the latter polymer with preformed LCP, have been employed as compatibilizing additives for blends of PE with a semirigid LCP. The morphology and the rheological and mechanical properties of the ternar…
Nanoclays for Conservation
2019
Within the conservation of artworks materials, this chapter describes innovative strategies based on clay nanoparticles that are promising for protective coating, surface cleaning, and consolidation. We present the preparation of polymer/montmorillonite nanocomposites, which are revealed as efficient protective coatings for highly porous stones, marbles, and bread-made artifacts. Anticorrosive films for metal substrates have been obtained by polymer filling with laponite and halloysite nanotubes (HNTs) containing corrosion inhibitors into their lumen. The dispersion of hydrophobically modified HNTs into chitosan matrix drives to fabricate biofilms with surface cleaning capacity. Rust stains…
Strain rate effect in the single-fiber-fragmentation test
2001
The single fiber fragmentation test (SFFT) has been widely used to characterize the interface in fiber-reinforced polymers. The purpose of the work reported here was to determine the effect of strain rate on the fiber fragment lengths obtained in the SFFT. Three materials systems were used to make single-fiber-composite specimens: E-glass fiber/polycarbonate matrix, AS4-carbon fiber/polycarbonate matrix, and AU4-carbon fiber/polycarbonate matrix. The fiber-matrix adhesion in all three systems is based on physisorption rather than chemisorption. Each system was tested at strain rates ranging over four orders of magnitude. Results are reported in terms of fragment length, the dependent variab…
Dependence of Coefficient of volumetric thermal expansion (CVTE) of glass fiber reinforced (GFR) polymers on the glass fiber content
2007
In a Glass Fiber Reinforced (GFR) polymer, the coefficient of volumetric thermal expansion CVTE (determined as a sum of the coefficients of linear thermal expansion CLTE’s for the three principal directions) is sometimes much smaller than the value predictable on the basis of well acquainted models, such as Chow model, taking into account fibers anisotropy and aspect ratio.
Indentation test as a tool for monitoring the solidification process during injection molding
2003
An inline method for monitoring the solidification process during the injection molding of semicrystalline polymers is demonstrated. The method has been applied to various poly(ethylene terephthalate) (PET) and poly(buthylene terephthalate) (PBT) samples. The technique is based on a simple device by which an additional ejector pin is pushed onto the injection-molded part with a fixed force at different times during the solidification phase while the mold remains closed. The residual deformation (the so-called indentation depth) due to the applied load is measured offline after ejection. By the performance of indentation at different times during the cooling phase, an indentation depth profi…
Characterization of a fiber reinforced semirigid liquid crystalline polymer
1997
In this work, samples of a semirigid Liquid crystalline polymer reinforced with carbon and glass fibers has been characterized. Semirigid liquid crystalline polymers (LCPs) show some advantages with respect to rigid LCPs: in particular lower processing temperatures, and better compatibility with flexible thermoplastics, but also some disadvantages: lower mechanical properties and poor thermomechanical resistance. Both properties can be improved by adding inorganic fillers. Although elastic modulus and tensile strength of the glass fiber filled LCP improve remarkably with increasing the filler content, the same properties for the carbon fiber-filled samples do not increase with increasing ti…