Outstanding Tensile Strength Research Articles

Covalent integration of differently structured polyester polyols improves the toughness and strength of cationically polymerized, amorphous epoxy networks

ABSTRACTThe structure–property relationship of polyester polyols in cationically polymerized, amorphous epoxy‐based copolymers is investigated. An epoxy resin is polymerized in the presence of structurally different polyesters. These resulting copolymers show improved tensile strength and toughness. The optimal epoxide/polyester ratio depends on the structure of the polyesters. Poly(δ‐valerolactone) (PVL) reveals the highest ester group density of the investigated polyesters, which enhances physical interactions with the epoxide during polymerization as well as in the network. Furthermore, PVL leads to outstanding tensile strength, strain at break, and toughness. Among all polyester polyols examined, PVL leads to the highest gel fraction or, in other words, the most complete integration into the epoxy network. This work shows that polyesters that are present in the reactive system should be covalently integrated into the polymer network as completely as possible to obtain good mechanical properties of the amorphous copolymer. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43986.

Modification of Vietnam Natural Rubber via Graft Copolymerization with Styrene

Graft copolymerization of styrene onto deproteinized natural rubber (DPNR) using tert-butyl hydroperoxide (TBHPO) and tetraethylene pentamine (TEPA) as redox initiator have been investigated. The effects of initiator and monomer concentration on conversion and grafting efficiency were studied. The dynamic mechanical and thermal properties of the graft copolymer were investigated over the wide range of temperatures. It is shown that a high value of storage modulus for the graft copolymer, which was about 25 times as high as that of DPNR, was achieved. The graft copolymer (DPNR-graft -PS) showed the outstanding tensile strength and stable thermal properties. These enhancements were attributed to the interaction between NR and polystyrene as a result of the graft copolymerization. Morphology observation by transmission electron micrograph (TEM) revealed that the core-shell arrangement of the DPNR-graft -PS with about 30 nm in thickness of polystyrene nano-layer was achieved.

The Machinability of CFRP with Cutting Movement of End-Milling

Recently, carbon fiber reinforced plastics (CFRP) are expected to be used more in the aerospace and automotive industries, because of their outstanding lightweight material characteristics and tensile strength [1][2]. Underlying this are problems closely related to improvement of the earth’s environment. However, a mechanical property is influenced by the difference in the distribution state of the carbon fiber, and the adhesion intensity of the binding material. Moreover, they have the characteristic of intense anisotropy, strength wise depending on the orientation of the carbon fibers [3][4]. Therefore, CFRPs are considered difficult-to-machine materials [5], because the surface finish deteriorates according to the carbon fiber orientation. Establishing the optimal cutting conditions to solve such problems also from an economical viewpoint is essential. In our study, end milling operations of different carbon fiber orientation CFRP composite material were investigated with three kinds of different helix angle end mills. Evaluations were based on the surface finish, cutting force and cutting temperature. Moreover, the relationships between the carbon fiber orientation and the machining operations were determined. We earlier evaluated the machinability from the relationship between carbon fiber orientation and tool helix angle by down-cut milling to solve these problems [6]. In this study, machining operations of different carbon fiber orientation CFRP composite material were investigated with three kinds of different helix angle end mills by up-cut milling. Evaluations were based on the surface finish, cutting force and cutting temperature. Moreover, the results of this experiment were compared with the results of down-cut milling.

Preparation, mechanical and degradation properties of Mg–Y-based microwire

Mg–Y-based microwire which offers high strength in combination of low degradation rate has been prepared for the first time by a modified melt extraction technique. A circular Mg–Y-based microwire is achieved with an extraction rate of 40m/s, which is composed of Mg matrix and an amorphous phase, and exhibits higher basal texture than that of as-cast sample. The outstanding tensile strength accompanying with an acceptable elongation is obtained with an extraction rate of 40m/s. The improved strength is mainly attributed to high solid solution strengthening, fine grain and the presence of an amorphous phase. In addition, the reduction of secondary phase and homogenous microstructure after melt extraction eliminate both pitting corrosion and micro-galvanic corrosion. A low degradation rate of 0.366mm/y is attained in a simulated body fluid, which is less than 1/10 of that of as-cast sample. These excellent mechanical properties and low degradation rate provide some prerequisites to develop bio-Mg implants. It reveals that this modified extraction technique is one of effective approaches to prepare microwire, which can be directly used for Mg-based stent self-assembly.

Nanoscale surface analysis on second generation advanced high strength steel after hot dip galvanizing

Second generation advanced high strength steel is one promising material of choice for modern automotive structural parts because of its outstanding maximal elongation and tensile strength. Nonetheless there is still a lack of corrosion protection for this material due to the fact that cost efficient hot dip galvanizing cannot be applied. The reason for the insufficient coatability with zinc is found in the segregation of manganese to the surface during annealing and the formation of manganese oxides prior coating. This work analyses the structure and chemical composition of the surface oxides on so called nano-TWIP (twinning induced plasticity) steel on the nanoscopic scale after hot dip galvanizing in a simulator with employed analytical methods comprising scanning Auger electron spectroscopy (SAES), energy dispersive X-ray spectroscopy (EDX), and focused ion beam (FIB) for cross section preparation. By the combination of these methods, it was possible to obtain detailed chemical images serving a better understanding which processes exactly occur on the surface of this novel kind of steel and how to promote in the future for this material system galvanic protection.

Graphene-based photonic devices for soft hybrid optoelectronic systems

Graphene, a two-dimensional one-atom-thick planar sheet of carbon atoms densely packed in a honeycomb crystal lattice, has attracted appreciable attention due to its extraordinary mechanical, thermal, electrical, and optical properties. One of these properties, graphene’s outstanding tensile strength, allows graphene-based electronic and photonic devices to be flexible, stretchable, and foldable. In this work, we propose a novel platform technology and architecture of graphene-based flexible photonic devices for the development of high-performance flexible devices and components. We investigated the characteristics of the graphene-based plasmonic waveguide for the development of high-performance optical interconnection in flexible human-friendly optoelectronic devices. We concluded that graphene-based photonic devices have huge potential for the development of next-generation human-friendly flexible optoelectronic systems.

Preparation and properties of polytetrafluorethylene filled ethylene–propylene–diene monomer composites

AbstractEthylene–propylene–diene monomer/polytetrafluorethylene (EPDM/PTFE) composites based on EPDM and electron beam irradiated PTFE powders (MS‐II, MS‐III, and MS‐V, with mean diameter 5 μm, 1 μm, and 0.1 μm, respectively) were prepared by a mechanical compounding technique. The curing characteristics, morphologies, mechanical properties, and abrasion behaviors of these composites were investigated. The curing measurements indicated that the addition of lower loading of MS‐III or MS‐V enhanced the lubrication of EPDM compounds and delayed the curing process. The morphological structure of the composites demonstrated that the MS‐III and MS‐V were uniformly dispersed in EPDM matrix and the efficient polymer–filler interfacial interactions were constructed. In comparison with EPDM/MS‐II and EPDM/MS‐III, EPDM/MS‐V exhibited outstanding tensile strength, tear strength, elongation at break, and abrasion resistance due to the nanometer particle dimension and good dispersion of MS‐V as well as the stronger interfacial interactions between MS‐V and the EPDM matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Nitrile rubber/organomontmorillonite nanocomposites produced by solution and melt compounding: Effect of the polarity of the quaternary ammonium intercalants

AbstractA comparative study of the development of nitrile rubber (NBR) based nanocomposites was performed; two organomontmorillonites (Cloisite 15A and Cloisite 30B) and two procedures for clay dispersion (melt blending and solution intercalation) were used. The nanocomposites were cured with a system based on dicumyl peroxide in the presence of m‐phenylenebismaleimide as a coagent for curing. The dispersion of the organoclay inside the NBR matrix was investigated with transmission electron microscopy and X‐ray diffraction. All the cured systems displayed a combination of intercalated, partially exfoliated clay platelets and confined, deintercalated clay; the degree of dispersion depended on the amount of clay, the type of intercalant, and the intercalation procedure. The highest amount of intercalated/exfoliated clay was obtained with a previous dispersion of the clay (Cloisite 30B) in an NBR solution. All the nanocomposites presented outstanding tensile strength and creep response, and this indicated a reinforcing effect of the layered silicates. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Synthesis and evaluation of properties of novel poly(benzimidazole‐amide)s

AbstractNovel aromatic polyamides have been prepared by a combination of diacids containing preformed benzimidazole rings and aromatic diamines. By the phosphorylation method of polycondensation, polymers of high molecular weight (inherent viscosities between 0.81 and 2.13 dL/g) were obtained, which showed good solubility in polar aprotic solvents. The combination of aromatic amide linkages and benzimidazole rings along the polymer chain endowed the polymers with high thermal resistance and excellent mechanical properties. Glass transition temperatures fell in the range of 290–330 °C as measured by differential scanning calorimetry, and initial decomposition temperatures under nitrogen were over 480 °C as measured by thermogravimetric analysis. Some polymer films showed outstanding tensile strength (over 150 MPa) and moduli (up to 5 GPa). The presence of benzimidazole rings in the current polyamides greatly enhanced their hydrophilicity in comparison with classical wholly aromatic polyamides; thus, although aromatic polyamide films normally show water sorption values of only 4–8%, some of the current poly(benzimidazole amide)s show water sorption up to 19% in a 65% relative humidity atmosphere. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7566–7577, 2008

HAYNES WASPALOY

Abstract Haynes Waspaloy is a specially vacuum melted, nickel-base alloy having outstanding tensile and stress-rupture strength up to 760 deg C (1400 deg F) combined with high oxidation resistance up to 871 deg C (1600 deg F). It is recommended for gas turbine engines, airframe assemblies, and missile systems. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as heat treating and machining. Filing Code: Ni-560. Producer or source: Haynes International Inc.

FRP-encased concrete as a structural material

Synopsis Plastics reinforced with continuous glass fibres have outstanding tensile strength in the fibre direction and excellent corrosion resistance, but are characterized by low modulus and low compressive strength. It is proposed to develop composite members in which a prefabricated FRP (fibreglass-reinforced-plastic) casing is used initially as the form to cast plain concrete, and thereafter to confine the concrete, act as tensile reinforcement and provide corrosion protection. Significant cost savings are possible with the proposed combination of materials, especially in exposed structures, such as bridges. An experimental investigation of FRP-encased concrete cylinders in axial compression and of rectangular FRP-encased beams in bending is presented. The results demonstrate the excellent strength and ductility characteristics of FRP-encased members. The behaviour of circular FRP-encased concrete beam-columns is described also, in terms of analytically obtained moment-axial-load and ductility-axial-load interaction diagrams and moment-curvature relations. The weathering characteristics and the fire resistance of the FRP are discussed, and measures to improve these environmental properties are reviewed.

UDIMET WASPALOY

Abstract UDIMET WASPALOY is a nickel-base, austenitic, precipitation-hardenable alloy. It features outstanding tensile and stress-rupture strength up to 1400 F and high oxidation resistance up to 1600 F. It is used widely in gas turbine engines, airframe assemblies and missile systems. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness, creep, and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-257. Producer or source: Special Metals Corporation.