PCEs are composed by a methoxy-polyethylene glycol copolymer (side chain) grafted with methacrylic acid copolymer (main chain). The carboxylic acid COONa dissociates in water, providing a negative charge along the PCE backbone. The polyethylene oxide (PEO or MPEG) group affords a not uniform distribution of electron cloud, which gives a chemical polarity to the side chains. The number and the length of side chains are flexible parameters that are easy to change. When the side chains have a huge amount of EO units, they lower with their high molar mass the charge density of the polymer, which enables poor performances on cement suspensions. To have both parameters on the same time, long side chain and high charge density, one can keep the number of main-chain-units much higher than the number of side-chain-units.
Other articles related to "chemical structure, structure":
... in chemistry is the process of determining the chemical structure of molecules ... The methods by which one can determine the structure of a molecule include spectroscopy, such as nuclear magnetic resonance (NMR), infrared spectroscopy and Raman spectroscopy, electron ... The following are common methods for determining the chemical structure (Structural elucidation) X-ray diffraction Proton NMR Carbon-13 NMR Mass spectrometry Infrared spectroscopy The ...
... A data-compatibility problem has also been noted with CambridgeSoft's chemical structure drawing program, ChemDraw ... Word 2008 does not retain the structural information when a chemical structure is copied from ChemDraw and pasted into a document ... If a structure is recopied from a Word 2008 document, and is pasted back into ChemDraw, it appears as a non-editable image rather than a recognized chemical structure ...
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—Norman Mailer (b. 1923)