|
Polyether Block Amide
Polyether block amide or PEBA is a thermoplastic elastomer (TPE). It is known under the tradename of PEBAX® ( Arkema) and VESTAMID® E (Evonik Industries). It is a block copolymer obtained by polycondensation of a carboxylic acid polyamide ( PA6, PA11, PA12) with an alcohol termination polyether ( Polytetramethylene glycol PTMG), PEG). The general chemical structure is: : H O - ( C O - PA - C O - O - PE - O)n - H PEBA is a high performance thermoplastic elastomer. It is used to replace common elastomers – thermoplastic polyurethanes, polyester elastomers, and silicones - for these characteristics: lower density among TPE, superior mechanical and dynamic properties (flexibility, impact resistance, energy return, fatigue resistance) and keeping these properties at low temperature (lower than -40 ° C), and good resistance against a wide range of chemicals. It is sensitive to UV degradation, however. Applications PEBA is found in the sports equipment market: fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermoplastic Elastomer
Thermoplastic elastomers (TPE), sometimes referred to as thermoplastic rubbers, are a class of copolymers or a physical mix of polymers (usually a plastic and a rubber) that consist of materials with both thermoplastic and elastomeric properties. While most elastomers are thermosets, thermoplastics are in contrast relatively easy to use in manufacturing, for example, by injection moulding. Thermoplastic elastomers show advantages typical of both rubbery materials and plastic materials. The benefit of using thermoplastic elastomers is the ability to stretch to moderate elongations and return to its near original shape creating a longer life and better physical range than other materials. The principal difference between thermoset elastomers and thermoplastic elastomers is the type of cross-linking bond in their structures. In fact, crosslinking is a critical structural factor which imparts high elastic properties. Types There are six generic classes of commercial TPEs (design ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brittleness
A material is brittle if, when subjected to stress, it fractures with little elastic deformation and without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Breaking is often accompanied by a sharp snapping sound. When used in materials science, it is generally applied to materials that fail when there is little or no plastic deformation before failure. One proof is to match the broken halves, which should fit exactly since no plastic deformation has occurred. Brittleness in different materials Polymers Mechanical characteristics of polymers can be sensitive to temperature changes near room temperatures. For example, poly(methyl methacrylate) is extremely brittle at temperature 4˚C, but experiences increased ductility with increased temperature. Amorphous polymers are polymers that can behave differently at different temperatures. They may behave like a glass at low temperatures (the glass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antistatic
An antistatic agent is a compound used for treatment of materials or their surfaces in order to reduce or eliminate buildup of static electricity. Static charge may be generated by the triboelectric effect or by a non-contact process using a high voltage power source. Static charge may be introduced on a surface as part of an in-mold label printing process. The role of an antistatic agent is to make the surface or the material itself slightly conductive, either by being conductive itself, or by absorbing moisture from the air; therefore, some humectants can be used. The molecules of an antistatic agent often have both hydrophilic and hydrophobic areas, similar to those of a surfactant; the hydrophobic side interacts with the surface of the material, while the hydrophilic side interacts with the air moisture and binds the water molecules. Internal antistatic agents are designed to be mixed directly into the material, external antistatic agents are applied to the surface. Common ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrophilic
A hydrophile is a molecule or other molecular entity that is attracted to water molecules and tends to be dissolved by water.Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon'' Oxford: Clarendon Press. In contrast, hydrophobes are not attracted to water and may seem to be repelled by it. Hygroscopics ''are'' attracted to water, but are not dissolved by water. Molecules A hydrophilic molecule or portion of a molecule is one whose interactions with water and other polar substances are more thermodynamically favorable than their interactions with oil or other hydrophobic solvents. They are typically charge-polarized and capable of hydrogen bonding. This makes these molecules soluble not only in water but also in other polar solvents. Hydrophilic molecules (and portions of molecules) can be contrasted with hydrophobic molecules (and portions of molecules). In some cases, both hydrophilic and hydrophobic properties occur in a single molecule. An example of these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonwovens
Nonwoven fabric is a fabric-like material made from staple fibre (short) and long fibres (continuous long), bonded together by chemical, mechanical, heat or solvent treatment. The term is used in the textile manufacturing industry to denote fabrics, such as felt, which are neither woven nor knitted. Some non-woven materials lack sufficient strength unless densified or reinforced by a backing. In recent years, non-wovens have become an alternative to polyurethane foam. Applications Nonwoven fabrics are broadly defined as sheet or web structures bonded together by entangling fiber or filaments (and by perforating films) mechanically, thermally or chemically. They are flat or tufted porous sheets that are made directly from separate fibres, molten plastic or plastic film. They are not made by weaving or knitting and do not require converting the fibres to yarn. Typically, a certain percentage of recycled fabrics and oil-based materials are used in nonwoven fabrics. The percentage o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Textiles
Textile is an umbrella term that includes various fiber-based materials, including fibers, yarns, filaments, threads, different fabric types, etc. At first, the word "textiles" only referred to woven fabrics. However, weaving is not the only manufacturing method, and many other methods were later developed to form textile structures based on their intended use. Knitting and non-woven are other popular types of fabric manufacturing. In the contemporary world, textiles satisfy the material needs for versatile applications, from simple daily clothing to bulletproof jackets, spacesuits, and doctor's gowns. Textiles are divided into two groups: Domestic purposes onsumer textilesand technical textiles. In consumer textiles, aesthetics and comfort are the most important factors, but in technical textiles, functional properties are the priority. Geotextiles, industrial textiles, medical textiles, and many other areas are examples of technical textiles, whereas clothing a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catheter
In medicine, a catheter (/ˈkæθətər/) is a thin tubing (material), tube made from medical grade materials serving a broad range of functions. Catheters are medical devices that can be inserted in the body to treat diseases or perform a surgical procedure. Catheters are manufactured for specific applications, such as cardiovascular, urological, gastrointestinal, neurovascular and ophthalmic procedures. The process of inserting a catheter is ''catheterization''. In most uses, a catheter is a thin, flexible tube (''soft'' catheter) though catheters are available in varying levels of stiffness depending on the application. A catheter left inside the body, either temporarily or permanently, may be referred to as an "indwelling catheter" (for example, a peripherally inserted central catheter). A permanently inserted catheter may be referred to as a "permcath" (originally a trademark). Catheters can be inserted into a body cavity, duct, or vessel, brain, skin or adipose tissue. Fun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack the energy to ionize atoms, it can cause chemical reactions and causes many substances to glow or fluoresce. Consequently, the chemical and biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules. Short-wave ultraviolet light damages DNA and sterilizes surfaces with which it comes into contact. F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ski Boot
Ski boots are footwear used in skiing to provide a way to attach the skier to skis using ski bindings. The ski/boot/binding combination is used to effectively transmit control inputs from the skier's legs to the snow. History Ski boots were leather winter boots, held to the ski with leather straps. As skiing became more specialized, so too did ski boots, leading to the splitting of designs between those for alpine skiing and cross-country skiing. Modern skiing developed as an all-round sport with uphill, downhill and cross-country portions. The introduction of the cable binding started a parallel evolution of binding and boot. The binding looped a strap around the back of the boot to hold it forward into a metal cup at the toe. Boots with the sole extended rearward to produce a flange for the cable to firmly latch to become common, as did designs with semi-circular indentations on the heel for the same purpose. Effective cross-country skiing requires the boot to flex forward to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Damping Ratio
Damping is an influence within or upon an oscillator, oscillatory system that has the effect of reducing or preventing its oscillation. In physical systems, damping is produced by processes that dissipate the energy stored in the oscillation. Examples include Viscosity, viscous Drag (physics), drag (a liquid's viscosity can hinder an oscillatory system, causing it to slow down; see viscous damping) in mechanical systems, Electrical resistance and conductance, resistance in electronic oscillators, and absorption and scattering of light in optical oscillators. Damping not based on energy loss can be important in other oscillating systems such as those that occur in ecology, biological systems and Bicycle_and_motorcycle_dynamics#Lateral_motion_theory, bikes (ex. Suspension (mechanics)). Not to be confused with friction, which is a dissipative force acting on a system. Friction can cause or be a factor of damping. The damping ratio is a dimensionless measure describing how Harmonic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sports Equipment
Sports equipment, sporting equipment, also called sporting goods, are the tools, materials, apparel, and gear used to compete in a sport and varies depending on the sport. The equipment ranges from balls, nets, and protective gear like helmets. Sporting equipment can be used as protective gear or a tool used to help the athletes play the sport. Over time, sporting equipment has evolved because sports have started to require more protective gear to prevent injuries. Sporting equipment may be found in any department store or specific sporting equipment shops. History and development of sports Historically many sports players have developed their own sporting equipment over time. For instance, the use of a football dates back to ancient China, between 225 BC and 220 AD. As football remains the most popular sport in the 21st century, the material of the ball has completely changed over the centuries; from being made out of animal skin, to being lined with multiple layers of polyes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UV Degradation
In polymer chemistry photo-oxidation (sometimes: oxidative photodegradation) is the degradation of a polymer surface due to the combined action of light and oxygen. It is the most significant factor in the weathering of plastics. Photo-oxidation causes the polymer chains to break (chain scission), resulting in the material becoming increasingly brittle. This leads to mechanical failure and, at an advanced stage, the formation of microplastics. In textiles the process is called phototendering. Technologies have been developed to both accelerate and inhibit this process. For example, plastic building components like doors, window frames and gutters are expected to last for decades, requiring the use of advanced UV-polymer stabilizers. Conversely, single-use plastics can be treated with biodegradable additives to accelerate their fragmentation. Many pigments and dyes can similarly have effects due to their ability to absorb UV-energy. Susceptible polymers Susceptibility to phot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
