|
Emulsion Dispersion
An emulsion dispersion is thermoplastics or elastomers suspended in a liquid state by means of emulsifiers. Preparation Emulsions are thermodynamically unstable liquid/liquid dispersions that are stabilized. Emulsion dispersion is not about reactor blends for which one polymer is polymerized from its monomer in the presence of the other polymers; emulsion dispersion is a novel method of choice for the preparation of homogeneous blends of thermoplastic and elastomer. In emulsion dispersion system the preparation of well-fined polymers droplets may be acquired by the use of water as dispersing medium. The surfactant molecules adsorb on the surface of emulsion by creating a dispersion of droplets, which reduces interfacial tension and retards particle flocculation during mixing. The molecules of surfactant have polar and non-polar parts which act as an intermediary to combine polar and non-polar polymers; the intermolecular interactions between the polar and the non-polar polymer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intermolecular
An intermolecular force (IMF; also secondary force) is the force that mediates interaction between molecules, including the electromagnetic forces of attraction or repulsion which act between atoms and other types of neighbouring particles (e.g. atoms or ions). Intermolecular forces are weak relative to intramolecular forces – the forces which hold a molecule together. For example, the covalent bond, involving sharing electron pairs between atoms, is much stronger than the forces present between neighboring molecules. Both sets of forces are essential parts of force fields frequently used in molecular mechanics. The first reference to the nature of microscopic forces is found in Alexis Clairaut's work ''Théorie de la figure de la Terre,'' published in Paris in 1743. Other scientists who have contributed to the investigation of microscopic forces include: Laplace, Gauss, Maxwell, Boltzmann and Pauling. Attractive intermolecular forces are categorized into the following type ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase Separation
Phase separation is the creation of two distinct Phase (matter), phases from a single homogeneous mixture. The most common type of phase separation is between two immiscible liquids, such as oil and water. This type of phase separation is known as liquid-liquid equilibrium. Colloids are formed by phase separation, though not all phase separations forms colloids - for example oil and water can form separated layers under gravity rather than remaining as microscopic droplets in suspension. A common form of spontaneous phase separation is termed spinodal decomposition; it is described by the Cahn–Hilliard equation. Regions of a phase diagram in which phase separation occurs are called miscibility gaps. There are two boundary curves of note: the binodal, binodal coexistence curve and the spinodal, spinodal curve. On one side of the binodal, mixtures are absolutely stable. In between the binodal and the spinodal, mixtures may be metastable: staying mixed (or unmixed) absent some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micrograph
A micrograph is an image, captured photographically or digitally, taken through a microscope or similar device to show a magnify, magnified image of an object. This is opposed to a macrograph or photomacrograph, an image which is also taken on a microscope but is only slightly magnified, usually less than 10 times. Micrography is the practice or art of using microscopes to make photographs. A photographic micrograph is a photomicrograph, and one taken with an electron microscope is an electron micrograph. A micrograph contains extensive details of microstructure. A wealth of information can be obtained from a simple micrograph like behavior of the material under different conditions, the phases found in the system, failure analysis, grain size estimation, elemental analysis and so on. Micrographs are widely used in all fields of microscopy. Types Photomicrograph A light micrograph or photomicrograph is a micrograph prepared using an optical microscope, a process referred to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scanning Electron Microscopy
A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that contain information about the surface topography and composition. The electron beam is scanned in a raster scan pattern, and the position of the beam is combined with the Intensity (physics), intensity of the detected signal to produce an image. In the most common SEM mode, secondary electrons emitted by atoms excited by the electron beam are detected using a secondary electron detector (Everhart–Thornley detector). The number of secondary electrons that can be detected, and thus the signal intensity, depends, among other things, on specimen topography. Some SEMs can achieve resolutions better than 1 Nanometre, nanometer. Specimens are observed in high vacuum in a Convention (norm), conventional SEM, or in low vacuum or wet conditions in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compatibility (chemical)
Chemical compatibility is a rough measure of how stable a substance is when mixed with another substance. If two substances can mix together and not undergo a chemical reaction, they are considered compatible. Incompatible chemicals react with each other, and can cause corrosion, mechanical weakening, evolution of gas, fire, or other undesirable interactions. Chemical compatibility is important when choosing materials for chemical storage or reactions, so that the vessel and other apparatus will not be damaged by its contents. For purposes of chemical storage, chemicals that are incompatible should not be stored together, so that any leak will not cause an even more dangerous situation from chemical reactions. In addition, chemical compatibility refers to the container material being acceptable to store the chemical or for a tool or object that comes in contact with a chemical to not degrade. For example, when stirring a chemical, the stirrer must be stable in the chemical that is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glass Transition Temperature
The glass–liquid transition, or glass transition, is the gradual and reversible transition in amorphous materials (or in amorphous regions within semicrystalline materials) from a hard and relatively brittle "glassy" state into a viscous or rubbery state as the temperature is increased. ISO 11357-2: Plastics – Differential scanning calorimetry – Part 2: Determination of glass transition temperature (1999). An amorphous solid that exhibits a glass transition is called a glass. The reverse transition, achieved by supercooling a viscous liquid into the glass state, is called vitrification. The glass-transition temperature ''T''g of a material characterizes the range of temperatures over which this glass transition occurs (as an experimental definition, typically marked as 100 s of relaxation time). It is always lower than the melting temperature, ''T''m, of the crystalline state of the material, if one exists, because the glass is a higher energy state (or enthalpy at const ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermogram
Infrared thermography (IRT), thermal video or thermal imaging, is a process where a Thermographic camera, thermal camera captures and creates an image of an object by using infrared radiation emitted from the object in a process, which are examples of infrared imaging science. Thermographic cameras usually detect electromagnetic radiation, radiation in the long-infrared range of the electromagnetic spectrum (roughly 9,000–14,000 nanometers or 9–14 μm) and produce images of that radiation, called thermograms. Since infrared radiation is emitted by all objects with a temperature above absolute zero according to the black body Planck's law of black-body radiation, radiation law, thermography makes it possible to see one's environment with or without optical spectrum, visible illumination. The amount of radiation emitted by an object increases with temperature; therefore, thermography allows one to see variations in temperature. When viewed through a thermal imaging camera, war ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Scanning Calorimetry
Differential scanning calorimetry (DSC) is a thermoanalytical technique in which the difference in the amount of heat required to increase the temperature of a sample and reference is measured as a function of temperature. Both the sample and reference are maintained at nearly the same temperature throughout the experiment. Generally, the temperature program for a DSC analysis is designed such that the sample holder temperature increases linearly as a function of time. The reference sample should have a well-defined heat capacity over the range of temperatures to be scanned. Additionally, the reference sample must be stable, of high purity, and must not experience much change across the temperature scan. Typically, reference standards have been metals such as indium, tin, bismuth, and lead, but other standards such as polyethylene and fatty acids have been proposed to study polymers and organic compounds, respectively. The technique was developed by E. S. Watson and M. J. O'Ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nylon 6
Nylon 6 or polycaprolactam is a polymer, in particular semicrystalline polyamide. Unlike most other nylons, nylon 6 is not a condensation polymer, but instead is formed by ring-opening polymerization; this makes it a special case in the comparison between condensation and addition polymers. Its competition with nylon 66 and the example it set have also shaped the economics of the synthetic fibre industry. It is sold under numerous trade names including Perlon (Germany), Dederon (former East Germany), Nylatron, Capron, Ultramid, Akulon, Kapron (former Soviet Union and satellite states), Rugopa (Turkey) and Durethan. History Polycaprolactam was developed by Paul Schlack at IG Farben in late 1930s (first synthesized in 1938) to reproduce the properties of Nylon 66 without violating the patent on its production. (Around the same time, Kohei Hoshino at Toray also succeeded in synthesizing nylon 6.) It was marketed as Perlon, and industrial production with a capacity of 3,500 tons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LDPE
Low-density polyethylene (LDPE) is a thermoplastic made from the monomer ethylene. It was the first grade of polyethylene, produced in 1933 by John C. Swallow and M.W Perrin who were working for Imperial Chemical Industries (ICI) using a high pressure process via free radical polymerization. Its manufacture employs the same method today. The EPA estimates 5.7% of LDPE ( resin identification code 4) is recycled in the United States. Despite competition from more modern polymers, LDPE continues to be an important plastic grade. In 2013 the worldwide LDPE market reached a volume of about US$33 billion. Despite its designation with the recycling symbol, it cannot be as commonly recycled as No. 1 (polyethylene terephthalate) or 2 plastics (high-density polyethylene). Properties LDPE is defined by a density range of 917–930 kg/m3. At room temperature it is not reactive, except to strong oxidizers; some solvents cause it to swell. It can withstand temperatures of continuou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
