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Food contact material pictogram (left) on a plastic food container in Hong Kong. Food contact materials or food contacting substances (FCS) [1] [2] are materials that are intended to be in contact with food. These can be things that are quite obvious like a glass or a can for soft drinks as well as machinery in a food factory or a coffee machine.
Variations in the environment, particularly temperature and pressure can change a nonmetal into a metal, and vica versa; this is always associated with some major change in the structure, a phase transition. Other external stimuli such as electric fields can also lead to a local nonmetal, for instance in certain semiconductor devices.
In 1802 the term "metalloids" was introduced for elements with the physical properties of metals but the chemical properties of non-metals. [194] However, in 1811, the Swedish chemist Berzelius used the term "metalloids" [195] to describe all nonmetallic elements, noting their ability to form negatively charged ions with oxygen in aqueous ...
An example of an ionomer, with carboxylate groups bound to a zinc cation. An ionomer (/ ˌ aɪ ˈ ɑː n ə m ər /) (iono-+ -mer) is a polymer composed of repeat units of both electrically neutral repeating units and ionized units covalently bonded to the polymer backbone as pendant group moieties.
Plastic bottles made from PET are widely used for soft drinks, both still and sparkling. For beverages that are degraded by oxygen, such as beer, a multilayer structure is used. PET sandwiches an additional polyvinyl alcohol (PVOH) or polyamide (PA) layer to further reduce its oxygen permeability.
When comparing a polar and nonpolar molecule with similar molar masses, the polar molecule in general has a higher boiling point, because the dipole–dipole interaction between polar molecules results in stronger intermolecular attractions. One common form of polar interaction is the hydrogen bond, which is also
An Ion gel (or Ionogel) is a composite material consisting of an ionic liquid immobilized by an inorganic or a polymer matrix. [ 1 ] [ 2 ] [ 3 ] The material has the quality of maintaining high ionic conductivity while in the solid state.
A polymer (/ ˈ p ɒ l ɪ m ər / [4] [5]) is a substance or material that consists of very large molecules, or macromolecules, that are constituted by many repeating subunits derived from one or more species of monomers. [6]