Atom transfer radical polymerization and copolymerization of vinyl acetate catalyzed by copper halide/terpyridine

Differences in microbial community composition and factors affecting different particulate matter during autumn in three cities of Xinjiang, China

Environmental pollution has become an issue of increasing concern in China, owing to the country's rapid economic development. Atmospheric particulate matter (PM) is known to be an important parameter in air quality monitoring; further, bioaerosol forms a crucial component of PM. As the climatic environments in the north and south of Xinjiang, China, are significantly different, here, atmospheric PM samples collected from three cities, Shihezi, Yining, and Tumushuk, located in different directions, were analysed for a better understanding of the spatial distribution patterns of microbial community composition of Xinjiang. The16s rDNA and 18 s rDNA were used to locate bacteria and fungi in PM_2.5, PM₁₀, and total suspended particulate matter (TSP) at the species level and genus level, and the microbial communities with the top 15 abundances were selected for analysis. The reports indicate that the most abundant group in Shihezi and Yining was Cenchrus_americanus, which belongs to Proteobacteria. The remaining 14 dominant species had their own distribution pattern in each city. The most dominant strain in Tumushuk was Bacillus_taeanensis, but this strain was not detected in Yining and Shihezi. Similarly, the most predominant fungus in Tumushuk (Microdorylaimus_miser under Myriophyllum) was not detected in the other two cities. The analysis of the effect of environmental impact factors on bacteria and fungi revealed that the impact factors such as temperature, humidity, and wind speed had a greater effect on microorganisms, while O₃ had a negative correlation with most microorganisms, owing to its toxicity. Overall, the results of this study show that short-range transported air masses have a greater impact on local pollutants and microorganisms.

Surface-Initiated Cu(0)-Mediated CRP for the Rapid and Controlled Synthesis of Quasi-3D Structured Polymer Brushes

Surface-initiated controlled radical polymerization mediated by Cu(0) plate (SI-Cu(0)_plate-CRP) is an extremely effective and versatile technique for the synthesis of functional polymer brushes from vinyl monomers on planar substrates. The advantages of SI-Cu(0)_plate-CRP in comparison to "classical" SI-CRP methods not only rely on the easy accessibility, handling, and recycling of the catalyst source, but also on the faster brush growth rates, and exceptionally high reinitiation efficiencies and grafting densities for the obtained brushes. The confined geometry of the SI-Cu(0)_plate-CRP reaction setup, with a Cu(0) plate placed in close proximity to the initiator bearing substrate, considerably simplifies the preparation of polymer brushes over large areas, and the fabrication of gradient, patterned and arrayed polymer brushes. In this viewpoint we summarize the recent developments and applications of SI-Cu(0)_plate-CRP, emphasizing its mechanism, advantages, and standing challenges.

Straightforward synthesis of model polystyrene-block-poly(vinyl alcohol) diblock polymers

Well-defined polystyrene-block-poly(vinyl alcohol) (PS-b-PVA) polymers were synthesizedviaRDRP protocols. The morphology of the block polymers was investigated by GISAXS and AFM.

Opportunities for dual RDRP agents in synthesizing novel polymeric materials

Dual RDRP agents provide access to new polymeric materials by combining ATRP, NMP, and RAFT polymerization without end group transformations.

Surface-initiated controlled radical polymerizations from silica nanoparticles, gold nanocrystals, and bionanoparticles

This review summarizes recent progress in surface-initiated controlled radical polymerizations from silica nanoparticles, gold nanocrystals, and bionanoparticles.

Uniform polymer-protein conjugate by aqueous AGET ATRP using protein as a macroinitiator

In situ aqueous activators generated by electron transfer for atom transfer radical polymerization (AGET ATRP) in air, using an enzyme as a macroinitiator, has been proposed to prepare uniform polymer-protein conjugates with improved stability under adverse conditions. In the first step, an initiator, 2-bromoisobutyryl bromide (BIB), was grafted onto the protein surface by reaction with the amino groups. The second step was in situ AGET ATRP polymerization in air using CuBr(2)/1,1,4,7,7-pentamethyldiethylenetriamine as a catalyst and ascorbic acid as a reducing agent. The effectiveness of this method has been demonstrated using horseradish peroxidase (HRP) as a model protein and acrylamide as the monomer, which yielded HRP-polyacrylamide conjugate with a mean particle size of about 20-30 nm. The grafting of BIB onto HRP and the subsequent polymerization yielding a polyacrylamide chain were confirmed by nuclear magnetic resonance and matrix-assisted laser desorption ionization time-of-flight spectrometry analysis. The size of the conjugate was shown to be a function of monomer loading and reaction time. The HRP conjugates yielded essentially retained the catalytic behavior of HRP in free form, as shown by K(m) and V(max) values, but exhibited significantly enhanced thermal stability against high temperature and trypsin digestion. The use of protein as the macroinitiator prevented the formation of copolymer and thus facilitated purification of the protein conjugate. The uniform size indicates a well-defined composition of protein and polymer, which is essential for applications that request a precise control of the dosage of enzyme activity.

Copper(0)-mediated living radical polymerization of styrene

The use of zerovalent copper and commercially available ligands enables the control of the polymerisation of styrene at 90 °C in toluene.