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Polyethylenimine (PEI) or polyaziridine is a polymer with repeating units composed of the amine group and two carbon aliphatic CH 2 CH 2 spacers. Linear polyethyleneimines contain all secondary amines, in contrast to branched PEIs which contain primary, secondary and tertiary amino groups.
Polyetherimide (PEI; branded as Ultem [1]) is an amorphous, amber-to-transparent thermoplastic with characteristics similar to the related plastic PEEK.When comparing PEI to PEEK, the former is cheaper but has lower impact strength and a tighter temperature range.
Polyimines can be synthesised via a condensation reaction between aldehydes and (primary) amines. [2] During this reaction, water is also formed as byproduct. Often, the synthesis can be performed at room temperature, but to fully cure the materials and remove remaining water, they can be dried at slightly elevated temperatures and/or in vacuum.
Transient expression, more frequently referred to "transient gene expression", is the temporary expression of genes that are expressed for a short time after nucleic acid, most frequently plasmid DNA encoding an expression cassette, has been introduced into eukaryotic cells with a chemical delivery agent like calcium phosphate (CaPi) or polyethyleneimine (PEI). [1]
The improved retention of papermaking furnish components improves the operational efficiency of the paper machine, reduces the solids and organic loading in the process water loop, and can lower overall chemical costs. Typical chemicals used as retention aids are: polyacrylamide (PAM), polyethyleneimine (PEI), colloidal silica, and bentonite.
Pages for logged out editors learn more. Contributions; Talk; Polyethyleneimine
In organic chemistry, the Michael reaction or Michael 1,4 addition is a reaction between a Michael donor (an enolate or other nucleophile) and a Michael acceptor (usually an α,β-unsaturated carbonyl) to produce a Michael adduct by creating a carbon-carbon bond at the acceptor's β-carbon.
Diazo compounds have two main Lewis structures in resonance: R 2 >C − –N + ≡N and R 2 >CH=N + =N −. In organic chemistry, the diazo group is an organic moiety consisting of two linked nitrogen atoms at the terminal position.