ACS polymers Au最新文献

Itaconates available from renewable resources constitute a group of monomers that are used in several types of polymerizations. Their use in free-radical polymerizations (FRPs) is still limited due to the low propagation rate coefficients resulting in low polymerization rates and the occurrence of depropagation which is responsible for limited monomer conversion. Since FRP is considered very robust with few requirements concerning monomer purity, it is still interesting to investigate how itaconate FRP may become feasible. For this reason, copolymerizations of itaconates with other monomers well-suited for FRP are considered. In particular, copolymerization with acrylates appears to be interesting because the propagation rate of these monomers is high and depropagation is not operative at common polymerization temperatures. Copolymerizations of dibutyl and dicyclohexyl itaconate with butyl acrylate were performed to determine the copolymerization reactivity ratios required for tailoring copolymer composition. To limit the number of experiments, copolymerizations were carried out until high conversion and consumption of the individual monomers was obtained from ¹H NMR spectroscopy and quantitative size-exclusion chromatography.

Itaconates available from renewable resources constitute a group of monomers that are used in several types of polymerizations. Their use in free-radical polymerizations (FRPs) is still limited due to the low propagation rate coefficients resulting in low polymerization rates and the occurrence of depropagation which is responsible for limited monomer conversion. Since FRP is considered very robust with few requirements concerning monomer purity, it is still interesting to investigate how itaconate FRP may become feasible. For this reason, copolymerizations of itaconates with other monomers well-suited for FRP are considered. In particular, copolymerization with acrylates appears to be interesting because the propagation rate of these monomers is high and depropagation is not operative at common polymerization temperatures. Copolymerizations of dibutyl and dicyclohexyl itaconate with butyl acrylate were performed to determine the copolymerization reactivity ratios required for tailoring copolymer composition. To limit the number of experiments, copolymerizations were carried out until high conversion and consumption of the individual monomers was obtained from ¹H NMR spectroscopy and quantitative size-exclusion chromatography.

Unusual photophysical and scattering behavior is described for hyperbranched poly(phenylene sulfide) materials. These materials show interactions between the π systems of the aromatic monomer units in both ground and excited states, resulting in broad ranges for absorption and emission of light. The materials also display unusual scattering behavior; this is attributed to enhanced scattering by delocalized excited states resulting from the monomer unit interactions. This enhanced scattering is seen in the resonance Rayleigh scattering and second order scattering spectra. The ability to use these materials to construct a switch based on photoinduced scattering is demonstrated: application of ∼400 nm laser light increased scattering of 700 nm light by approximately 20%.

Unusual photophysical and scattering behavior is described for hyperbranched poly(phenylene sulfide) materials. These materials show interactions between the π systems of the aromatic monomer units in both ground and excited states, resulting in broad ranges for absorption and emission of light. The materials also display unusual scattering behavior; this is attributed to enhanced scattering by delocalized excited states resulting from the monomer unit interactions. This enhanced scattering is seen in the resonance Rayleigh scattering and second order scattering spectra. The ability to use these materials to construct a switch based on photoinduced scattering is demonstrated: application of ∼400 nm laser light increased scattering of 700 nm light by approximately 20%.

Coating materials involving nature-inspired compounds or renewable sources have recently attracted vast attention. This article presents the synthesis of modified rapeseed oil (MRO) as a precursor possessing high biobased carbon content suitable for cured thermosets formation. Two reactive diluents based on renewable sources, methacrylated methyl 3-hydroxybutyrate (M3HBMMA) and ethyl 3-hydroxybutyrate (E3HBMMA), were successfully synthesized. Lastly, isosorbide monomethacrylate (MISD) was suggested and produced as a polarity modifier miscible with modified curable oil systems capable of increasing the thermoset surface energy. All synthesized compounds were structurally analyzed via NMR, ESI-MS, and FTIR. The characterized reactive substances were coated on paper, stainless steel, and beech wood to investigate their suitability for forming thin layers. The paper dip coating verified the reactive diluting properties of M3HBMMA, resulting in the average formed coating deviation decrease (87.5% for undiluted MRO and 28.0% for 50 wt % M3HBMMA containing MRO). Also, the additional cured thermoset weight decreased from 350 to 69 wt % for the same systems. The standardized bend test applied on the coated stainless steel specimens revealed the thermoset's flexibility and adhesion increase from a 12 ± 2° bending angle of 100% pure MRO to a 121 ± 2° bending angle measured for 40 wt % E3HBMMA containing the MRO-based thermoset. The coated beech wood samples underwent the standardized cross-hatch test investigating the substrate's coating quality. The 100% MRO reached a level 1 rating (second worst), while the system with 40 wt % of MISD obtained a level 5 rating (the best).

Coating materials involving nature-inspired compounds or renewable sources have recently attracted vast attention. This article presents the synthesis of modified rapeseed oil (MRO) as a precursor possessing high biobased carbon content suitable for cured thermosets formation. Two reactive diluents based on renewable sources, methacrylated methyl 3-hydroxybutyrate (M3HBMMA) and ethyl 3-hydroxybutyrate (E3HBMMA), were successfully synthesized. Lastly, isosorbide monomethacrylate (MISD) was suggested and produced as a polarity modifier miscible with modified curable oil systems capable of increasing the thermoset surface energy. All synthesized compounds were structurally analyzed via NMR, ESI-MS, and FTIR. The characterized reactive substances were coated on paper, stainless steel, and beech wood to investigate their suitability for forming thin layers. The paper dip coating verified the reactive diluting properties of M3HBMMA, resulting in the average formed coating deviation decrease (87.5% for undiluted MRO and 28.0% for 50 wt % M3HBMMA containing MRO). Also, the additional cured thermoset weight decreased from 350 to 69 wt % for the same systems. The standardized bend test applied on the coated stainless steel specimens revealed the thermoset’s flexibility and adhesion increase from a 12 ± 2° bending angle of 100% pure MRO to a 121 ± 2° bending angle measured for 40 wt % E3HBMMA containing the MRO-based thermoset. The coated beech wood samples underwent the standardized cross-hatch test investigating the substrate’s coating quality. The 100% MRO reached a level 1 rating (second worst), while the system with 40 wt % of MISD obtained a level 5 rating (the best).

Polyethersulfone (PSU) as a commercially available polymer offers many different opportunities for functionalization for diverse fields of application, for example, electrophilic substitutions like sulfonation and bromination or nucleophilic reactions such as lithiation. This study presents three different polysulfone derivatives, first functionalized by a lithiation reaction, followed by a reaction with carbonyl compounds containing pentafluorophenyl groups. In the last step, the pentafluorophenyl moieties of the modified PSU were sulfonated by thiolation and subsequent oxidation to sulfonic acid groups. Those novel PSU derivatives were characterized by NMR, DSC, TGA, GPC, and titration. Based on these ionomers, we show the fabrication of pure and acid–base blend membranes with promising proton conductivities. These novel sulfonic acid groups containing materials are potentially promising candidates for membranes or ionomers in electrochemical applications such as proton exchange membrane fuel cells (PEMFCs), proton exchange membrane water electrolysis (PEMWEs), or redox flow batteries (RFBs).

Polyethersulfone (PSU) as a commercially available polymer offers many different opportunities for functionalization for diverse fields of application, for example, electrophilic substitutions like sulfonation and bromination or nucleophilic reactions such as lithiation. This study presents three different polysulfone derivatives, first functionalized by a lithiation reaction, followed by a reaction with carbonyl compounds containing pentafluorophenyl groups. In the last step, the pentafluorophenyl moieties of the modified PSU were sulfonated by thiolation and subsequent oxidation to sulfonic acid groups. Those novel PSU derivatives were characterized by NMR, DSC, TGA, GPC, and titration. Based on these ionomers, we show the fabrication of pure and acid-base blend membranes with promising proton conductivities. These novel sulfonic acid groups containing materials are potentially promising candidates for membranes or ionomers in electrochemical applications such as proton exchange membrane fuel cells (PEMFCs), proton exchange membrane water electrolysis (PEMWEs), or redox flow batteries (RFBs).