Synthesis and characterization of hydrophilic copolymers of maleimide derivatives with 2‐hydroxyethyl methacrylate: electrochemical and thermal behavior

BACKGROUND: The high‐technology industries have been the driving force in the development of new synthetic polymers that combine thermal stability with specific functional properties. In this study p‐chlorophenylmaleimide, p‐hydroxyphenylmaleimide and p‐nitrophenylmaleimide (R‐PhMI) with 2‐hydroxyethyl methacrylate (HEMA) were synthesized by free radical polymerization to obtain hydrophilic polymers, in order to study the effect of the p‐chloroaryl, p‐hydroxyaryl or p‐nitroaryl group on the copolymer composition, electrochemical behavior and thermal properties. RESULTS: The thermal behavior was correlated with the copolymer composition and functional groups, maleimide derivatives, on the copolymers. Thermal decomposition temperature (TDT) and glass transition temperature (T_g) were influenced by the functional groups of R‐PhMI moiety on the copolymer. The polymers showed an electrochemically irreversible reduction process under the conditions tested. CONCLUSION: Poly[(p‐chloromaleimide)‐co‐(2‐hydroxyethyl methacrylate)] copolymer shows a higher TDT than poly[(p‐hydroxymaleimide)‐co‐(2‐hydroxyethyl methacrylate)] or poly[(p‐nitromaleimide)‐co‐(2‐hydroxyethyl methacrylate)] (NPHE). T_g decreases in going from nitro to hydroxyl to chloro groups. The NPHE copolymer shows a lower stability, losing weight at 200 °C. The NPHE copolymer shows a well‐defined reduction wave which is similar to those of the other copolymers and it also shows an additional quasi‐reversible reduction wave corresponding to the nitrobenzene group. Copyright © 2009 Society of Chemical Industry     

Boron removal by liquid‐phase polymer‐based retention technique using poly(glycidyl methacrylate N‐methyl D‐glucamine)

The removal of boron was analyzed by liquid‐phase polymer based retention (LPR) technique using washing and enrichment method. The extracting reagents were water‐soluble polymers (WSPs) containing quaternary ammonium salts and N‐methyl‐D ‐glucamine (NMG) groups. The removal experiments of boron using the washing method were conducted at 1 bar of pressure by varying pH, polymer:boron molar ratio, and concentrations of interfering ions (chloride and sulfate). The results showed higher retention capacity for boron (60%) at pH 10 with the polymer containing NMG group. The optimal polymer:boron molar ratio was 40 : 1. Selectivity experiments showed that the presence of interfering ions did not affect the boron removal capacity. The maximal boron retention capacity was determined by the enrichment method, obtaining a value of 12 mg B/g‐polymer. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Novel non-alternating copolymers synthesized by spontaneous copolymerization of p-chlorophenylmaleimide with 2-methyl-2-oxazoline

Summary The copolymerization of p-chlorophenylmaleimide (1) as electrophilic monomer with 2-methyl-2-oxazoline (2) as nucleophilic monomer without initiator in solution under different experimental conditions was investigated. Copolymers were characterized by FT-IR and ¹H-NMR spectroscopy. The copolymer composition was determined from ¹H-NMR spectra. Molecular weights ranged between 1700 and 5400 g/mol by vapor pressure osmometry. Received: 27 September 1998/Revised version: 27 January 1999/Accepted: 28 January 1999     

Improving an autotuning engine for 3D Fast Wavelet Transform on manycore systems

This paper presents an enhanced auto-optimization method to run the 3D-Fast Wavelet Transform on different computing units in a system (GPU, MIC, CPU). The proposed method automatically selects a set of parameter values (block size, number of streams and number of threads) in order to reduce the total execution time, obtaining performances close to the optimal and decreasing the number of evaluations needed.     

Biostatic Behavior of Side Chain Charged Polycations and Polymer-Ag Complexes

Summary Poly[(3-methacryloylamino)propyl]trimethylammonium)chloride (PMF'TA), and poly (2-acrylamido-2-methyl-1-propane sulfonic acid) (PAPSA) were synthesized by radical polymerization. Three copolymers of (3-methacryloylamino)propyl] trimethylammonium chloride and 2-acrylamido-2-methyl-1-propane sulfonic acid P(MPTA-co-APSA) with different feed monomer mol ratios were also synthesized by radical polymerization. These polymer materials and the commercial poly(vinylpyrro1idone-co-2-dimethylaminoethyl methacrylate) quaternized P(VP-co- DMAEM) were purified by ultrafiltration membranes and subsequently their complexes with Ag(I) were prepared. Antibacterial activity of all these polymers, was investigated against Escherichia coli (6538P), and Staphylococcus aureus (ATCC 28922), using the National Comittee for Clinical Laboratory Standards method [1]. None of these compounds exhibited biocidal or biostatic action against E. coli, and only PMTA and P(VP-co-DMAEM) exhibited some action against S. aureus.     

FlexSched: Efficient scheduling techniques for concurrent kernel execution on GPUs

The Journal of Supercomputing - Nowadays, GPU clusters are available in almost every data processing center. Their GPUs are typically shared by different applications that might have different...     

Cellular genetic algorithms without additional parameters

Cellular genetic algorithms (cGAs) are a kind of genetic algorithms (GAs) with decentralized population in which interactions among individuals are restricted to close ones. The use of decentralized populations in GAs allows to keep the population diversity for longer, usually resulting in a better exploration of the search space and, therefore, in a better performance of the algorithm. However, it supposes the need of several new parameters that have a major impact on the behavior of the algorithm. In the case of cGAs, these parameters are the population and neighborhood shapes. We propose in this work two innovative cGAs with new adaptive techniques that allow removing the neighborhood and population shape from the algorithm’s configuration. As a result, the new adaptive cGAs are highly competitive (statistically) with all the compared cGAs in terms of the average solutions found in the continuous and combinatorial domains, while finding, in general, the best solutions for the considered problems, and with less computational effort.     

Hydrogels based on alkylated chitosan and polyelectrolyte copolymers

Hydrogels formed by alkylated chitosan with N‐(3‐chloro‐2‐hydroxypropyl) trimethylammonium chloride and synthetic copolymers forming polyelectrolyte complexes are presented. The copolymer polyelectrolytes were synthesized through free‐radical polymerization. Their compositions and reactivity parameters were determined by the Finemann–Ross and Kelen–Tüdos methods. The copolymers have structures that tend to be alternating. The hydrogels were characterized by thermogravimetric analysis, Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, scanning electron microscopy, and water solubility tests at different pH values. For the formation of the hydrogels, they were prepared using different molar ratios of alkylated chitosan and polyelectrolyte copolymers. Their stability was determined by rheological analysis, evaluating the response as a function of strain and frequency. The rheological tests showed that the stability of the polyelectrolyte complexes followed the trend ChT‐CP2 > ChT‐CP3 > ChT‐CP1 due to the presence of greater electrostatic interactions. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46556.