The application of five polymer amphiphiles in the gold‐catalyzed allene cycloisomerizations under aqueous micellar conditions is described. The polymers were prepared by ring‐opening cationic polymerization based on poly(2‐methyl‐2‐oxazoline) as hydrophilic segment and different hydrocarbon‐ or fluorocarbon‐based hydrophobic segments. The catalytic activity in the gold‐catalyzed allene cyclization is strongly dependent on the type of gold precursor, the salt concentration in the bulk aqueous medium, and the concentration of the polymeric amphiphile. Best results were obtained with 2 mol% of gold(III) bromide, 1 mM of amphiphile and 5 M sodium chloride, affording over 80% yield for different heterocyclic products. The catalyst system is also suitable for the dehydrative cyclization of acetylenic diols to furans. Moreover, successful catalyst recycling was demonstrated in three consecutive runs when using optimized extraction conditions.magnified image

Core‐crosslinked nanoparticles presenting secondary amine functional groups in the hydrophilic shell are synthesized by a bottom‐up approach. The route utilizes polymerization of 2‐oxazolines to prepare tailor‐made block copolymers with a primary or secondary amine end group in the hydrophilic block and alkynyl moieties in the hydrophobic part of the polymer. Upon solubilization in the aqueous media, these block copolymers form micelles that are photocrosslinked by a radical polymerization process to afford two types of core‐crosslinked nanoparticles, either with secondary amines, NP1, or primary amines, NP2, on the surface. The dimensions and stability of the core‐crosslinked nanoparticles are characterized by dynamic light scattering and fluorescence spectroscopy. The availability and reactivity of the amine groups in the hydrophilic shell are demonstrated by reaction with different aromatic model compounds resulting in a degree of surface functionalization of 4–47% for NP1 nanoparticles with secondary amino groups and a 20–95% degree of surface functionalization for NP2 with primary amine groups, as determined by UV–vis spectroscopy.

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Graft co‐ and terpolymers were prepared by free radical polymerizations of vinyl monomers onto ω‐irradiated starch by a prototype commercial process. Products with graft contents of up to 46%, by weight, were obtained by grafting acrylamide and quaternary amine‐containing esters of methacrylic acid to starch. The graft polymers were evaluated on a pilot fourdrinier paper machine as filler retention aids and compared with several commercial flocculants. Drainage rate increased markedly with one of the starch graft terpolymers that was cationic. Since the number of starch graft polymers prepared was limited, the results reported, although excellent, are not necessarily optimal. Further studies are needed to establish the relationships of graft content and terpolymer compositions to retention and drainage.