Carbonyl sulfide （COS）, an analogue of carbon dioxide （CO2）, can be converted to CO2 via the carbonic anhydride enzymes widely existing in nature. COS is an ideal monomer for making poly（monothiocarbonate）s, whi...Carbonyl sulfide （COS）, an analogue of carbon dioxide （CO2）, can be converted to CO2 via the carbonic anhydride enzymes widely existing in nature. COS is an ideal monomer for making poly（monothiocarbonate）s, which are difficult to synthesize by traditional methods. Herein, for the first time, we describe an anionic copolymerization of COS with epoxides using alkali metal alkoxides as the catalysts （initiators）, affording poly（monothiocarbonate）s with 100% alternating degree, 〉99% tail-to-head （T-H） content, high number-average molecular weights （Mns, up to 90.3 kg/mol） with narrow molecular weight distributions （D=Mw/Mn, 1.05-1.31 for COS/propylene oxide copolymers） under solvent-free and mild conditions. Oxygen-sulfur exchange reaction （O/S ER）, which can result in the production of contaminated dithiocarbonate and carbonate units in the main chain, was nearly completely depressed at 0 ℃. In addition, in contrast to previously reported salen chromium （iron） complexes that required multiple synthetic steps, this work provides simple, low-cost, and effective catalysts for making colorless sulfur-containing polymers.展开更多
A series of mixed, random cylindrical brush copolymers bearing polystyrene（PS） and poly（ε-caprolactone）（PCL） side chains were synthesized via the combination of ring-opening polymerization（ROP） and atom trans...A series of mixed, random cylindrical brush copolymers bearing polystyrene（PS） and poly（ε-caprolactone）（PCL） side chains were synthesized via the combination of ring-opening polymerization（ROP） and atom transfer radical polymerization（ATRP）. These novel cylindrical brush copolymers have been characterized by means of nuclear magnetic resonance（NMR） spectroscopy, gel permeation chromatography（GPC） and differential scanning calorimetry（DSC）. It was found that the mikto-armed cylindrical brush copolymers were microphase-separated in bulks and that the morphologies were dependent on the mass ratios of PS to PCL side chains. One of the cylindrical brush copolymers was employed to incorporate into epoxy thermoset to investigate effect of the mikto-armed cylindrical brush architecture on the reaction-induced microphase separation behavior. Depending on the concentration of the cylindrical brush in epoxy, the thermosets can display the morphologies with the spherical, worm-like and lamellar PS microdomains dispersing in continuous thermosetting matrices.展开更多
基金X. H. Z gratefully thanks the financial support of the Distinguished Young Investigator Fund of Zhejiang Province （No. LR16B040001） and the National Natural Science Foundation of China （No. 21774108）.
文摘Carbonyl sulfide （COS）, an analogue of carbon dioxide （CO2）, can be converted to CO2 via the carbonic anhydride enzymes widely existing in nature. COS is an ideal monomer for making poly（monothiocarbonate）s, which are difficult to synthesize by traditional methods. Herein, for the first time, we describe an anionic copolymerization of COS with epoxides using alkali metal alkoxides as the catalysts （initiators）, affording poly（monothiocarbonate）s with 100% alternating degree, 〉99% tail-to-head （T-H） content, high number-average molecular weights （Mns, up to 90.3 kg/mol） with narrow molecular weight distributions （D=Mw/Mn, 1.05-1.31 for COS/propylene oxide copolymers） under solvent-free and mild conditions. Oxygen-sulfur exchange reaction （O/S ER）, which can result in the production of contaminated dithiocarbonate and carbonate units in the main chain, was nearly completely depressed at 0 ℃. In addition, in contrast to previously reported salen chromium （iron） complexes that required multiple synthetic steps, this work provides simple, low-cost, and effective catalysts for making colorless sulfur-containing polymers.
基金financially supported by the National Natural Science Foundation of China(Nos.51133003,21274091 and 21774078)the Shanghai Synchrotron Radiation Facility under the projects(Nos.10sr0260 and 10sr0126)
文摘A series of mixed, random cylindrical brush copolymers bearing polystyrene（PS） and poly（ε-caprolactone）（PCL） side chains were synthesized via the combination of ring-opening polymerization（ROP） and atom transfer radical polymerization（ATRP）. These novel cylindrical brush copolymers have been characterized by means of nuclear magnetic resonance（NMR） spectroscopy, gel permeation chromatography（GPC） and differential scanning calorimetry（DSC）. It was found that the mikto-armed cylindrical brush copolymers were microphase-separated in bulks and that the morphologies were dependent on the mass ratios of PS to PCL side chains. One of the cylindrical brush copolymers was employed to incorporate into epoxy thermoset to investigate effect of the mikto-armed cylindrical brush architecture on the reaction-induced microphase separation behavior. Depending on the concentration of the cylindrical brush in epoxy, the thermosets can display the morphologies with the spherical, worm-like and lamellar PS microdomains dispersing in continuous thermosetting matrices.
