Poly trapping agents

Photochemically generated silylene species may react either with themselves to form poly silane polymers, or with a trapping agent added to intercept the species. The fate of the silylene and the structure of reaction products depend on the relative rates of these two processes, which may proceed simultaneously. 

Exemplary materials for the waterproofing of masonry surfaces are waterproof membranes such as poly(vinyl chloride), PE, butyl rubber, and sealants such as tar, asphalt, paints, poly(urethane), epoxy or mastics. While these waterproofing agents can offer excellent resistance to water penetration and other contaminants, they can alter the appearance of the masonry surface, e.g., they may change the color of the surface or leave it with a shine. Waterproofing treatments can also trap moisture within the masonry surface and promote spalling. 

The synthesis of DAAmEP was conducted in three steps. The first step was a Michaelis-Arhuzov reaction between N-(2-bromoethyl)phthalimide and an excess of triethyl phosphite under reflux at 160 °C for 12 h. In the second step, the reaction between the resulting phthalimide and hydrazine led to the formation of (2-aminoethyl)phosphonic acid diethyl ester. The final step consisted of the reaction between the actyloyl chloride and the diethyl ester, which was achieved in the presence of poly(4-vinylpyridine), 2% crosslinked, to trap the hydrochloric acid produced during the acryloylation. The final DAAmEP monomer was obtained after purification by chromatography on silica gel. All intermediate products were characterized by H and P NMR. The H NMR spectrum of the DAAmEP monomer allowed validation of the expected chemical structure and as a consequence the synthetic pathway. RAFT homopolymerization of DAAmEP was carried out with two different trithiocarbonate chain transfer agents (see Scheme 2.6). 

Biologically active molecules are sometimes trapped in PDMS when end-functionalized PDMS chains are linked into a network structure. This method has been done, for example, with a lipase enzyme. The PDMS plays a beneficial role as an activator or protective agent. Similar results were found for the enzyme a-chymotripsin, with some short-chain poly(ethylene oxide) used to enhance enzymatic activity. It is also possible to generate microtopographic patterns that affect Escherichia coU biofilm formation on PDMS surfaces. 

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