Search results
Results From The WOW.Com Content Network
Polyethylene was first synthesized by the German chemist Hans von Pechmann, who prepared it by accident in 1898 while investigating diazomethane. [12] [a] [13] [b] When his colleagues Eugen Bamberger and Friedrich Tschirner characterized the white, waxy substance that he had created, they recognized that it contained long −CH 2 − chains and termed it polymethylene.
Ultra-high-molecular-weight polyethylene (UHMWPE, UHMW) is a subset of the thermoplastic polyethylene.Also known as high-modulus polyethylene (HMPE), it has extremely long chains, with a molecular mass usually between 3.5 and 7.5 million amu. [1]
Molar mass: 28.054 g·mol −1 Appearance colourless gas Density: ... Polyethylene, also called polyethene and polythene, is the world's most widely used plastic.
Molar mass: 380-420 g/mol Density: 1.128 g/cm 3: Melting point: ... PEG 400 (polyethylene glycol 400) is a low-molecular-weight grade of polyethylene glycol. It is a ...
HDPE is known for its high strength-to-density ratio. [4] The density of HDPE ranges from 930 to 970 kg/m 3. [5] Although the density of HDPE is only marginally higher than that of low-density polyethylene, HDPE has little branching, giving it stronger intermolecular forces and tensile strength (38 MPa versus 21 MPa) than LDPE. [6]
The molar mass of atoms of an element is given by the relative atomic mass of the element multiplied by the molar mass constant, M u ≈ 1.000 000 × 10 −3 kg/mol ≈ 1 g/mol. For normal samples from Earth with typical isotope composition, the atomic weight can be approximated by the standard atomic weight [ 2 ] or the conventional atomic weight.
Polyethylene glycol (PEG; / ˌ p ɒ l i ˈ ɛ θ əl ˌ iː n ˈ ɡ l aɪ ˌ k ɒ l,-ˈ ɛ θ ɪ l-,-ˌ k ɔː l /) is a polyether compound derived from petroleum with many applications, from industrial manufacturing to medicine. PEG is also known as polyethylene oxide (PEO) or polyoxyethylene (POE), depending on its molecular weight.
Polyethylene terephthalate is produced largely from purified terephthalic acid (PTA), as well as to a lesser extent from (mono-)ethylene glycol (MEG) and dimethyl terephthalate (DMT). [ 41 ] [ 5 ] As of 2022, ethylene glycol is made from ethene found in natural gas , while terephthalic acid comes from p-xylene made from crude oil .