Aliphatic polyamides have been considered as eco-friendly materials,useful for a wide range of applications.However,it still presents obstacle to produce sustainable aliphatic polyamides from abundant renewable source...Aliphatic polyamides have been considered as eco-friendly materials,useful for a wide range of applications.However,it still presents obstacle to produce sustainable aliphatic polyamides from abundant renewable sources.Herein,we describe that 4-hydroxyproline(4-HYP),a renewable resource,was readily converted to its corresponding bicyclic bridged lactam monomers bearing pendant Boc-protected secondary amino group,and oligo-ethylene glycol group.Lithium hexamethyldisilazide(LiHMDS)-mediated polymerization of the resulting monomers exhibited a controlled feature,affording sustainable aliphatic polyamides with number-average molecular weight up to 73 kg/mol and a low molecular weight distribution?<1.28.Overall,this work can lead to a novel kind of functional and sustainable polyamides with potential applications,including degradable plastics,and drug delivery.展开更多
A series of poly（lactic acid-4-hydroxyproline-polyethylene glycol） （PLA-Hpr-PEG） copolymers were synthesized by direct melt copolymerization of D,L-lactic acid and 4-hydroxyproline with different feed amount of po...A series of poly（lactic acid-4-hydroxyproline-polyethylene glycol） （PLA-Hpr-PEG） copolymers were synthesized by direct melt copolymerization of D,L-lactic acid and 4-hydroxyproline with different feed amount of polyethylene glycol （PEG） 0.1%, 0.5%, 1% and 5%, respectively. The properties of these copolymers were characterized by using IR spectroscopy, proton nuclear magnetic resonance （1H-NMR） spectroscopy, gel permeation chromatography （GPC）, X-ray diffraction and differential scaning calorimetry （DSC）. PLA-Hpr-PEG are amorphous copolymers. Copolymers showed increasing water uptake capacity with increasing PEG percentage in the feed, which result in an increasing degradable rate in phosphate buffer solution （pH 7.4） at 37℃.展开更多
采用Co_(3)O_(4)吸附脱除模拟柴油中的喹啉、吡啶或苯胺,考察了最佳吸附温度、吸附时间等条件,同时进行了吸附热力学和动力学研究;基于第一性原理对Co_(3)O_(4)晶胞进行相分析,对3种氮化物进行最高占据分子轨道(HOMO)-最低未占据分子轨...采用Co_(3)O_(4)吸附脱除模拟柴油中的喹啉、吡啶或苯胺,考察了最佳吸附温度、吸附时间等条件,同时进行了吸附热力学和动力学研究;基于第一性原理对Co_(3)O_(4)晶胞进行相分析,对3种氮化物进行最高占据分子轨道(HOMO)-最低未占据分子轨道(LUMO)分析,计算了吸附构型的吸附能和最稳定吸附构型的Mulliken电荷转移与电子密度。结果表明:在15 mL模拟柴油中加入0.6 g Co_(3)O_(4),苯胺、吡啶、喹啉的最佳吸附温度分别为20、20和30℃,最佳吸附时间分别为30、30、40 min,吸附容量由大到小顺序均为苯胺>吡啶>喹啉。热力学与动力学分析表明,喹啉、吡啶、苯胺的吸附均更符合多分子层吸附的Freundlich模型和准二级动力学方程。HOMO-LUMO分析结果表明,Co_(3)O_(4)为电子接受体,3种氮化物为电子给予体,Co_(3)O_(4)对喹啉、吡啶的配位吸附结构最稳定,对苯胺的π络合吸附最稳定。电荷转移计算表明,苯胺、吡啶、喹啉向Co_(3)O_(4)团簇转移的电荷数分别为0.423、0.394、0.368,说明Co_(3)O_(4)吸附3种氮化物的吸附能力大小为苯胺>吡啶>喹啉;电子密度图结果表明,最稳定吸附结构中Co_(3)O_(4)与3种氮化物均形成了化学键。展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.U21A2089 and 51873211)。
文摘Aliphatic polyamides have been considered as eco-friendly materials,useful for a wide range of applications.However,it still presents obstacle to produce sustainable aliphatic polyamides from abundant renewable sources.Herein,we describe that 4-hydroxyproline(4-HYP),a renewable resource,was readily converted to its corresponding bicyclic bridged lactam monomers bearing pendant Boc-protected secondary amino group,and oligo-ethylene glycol group.Lithium hexamethyldisilazide(LiHMDS)-mediated polymerization of the resulting monomers exhibited a controlled feature,affording sustainable aliphatic polyamides with number-average molecular weight up to 73 kg/mol and a low molecular weight distribution?<1.28.Overall,this work can lead to a novel kind of functional and sustainable polyamides with potential applications,including degradable plastics,and drug delivery.
文摘A series of poly（lactic acid-4-hydroxyproline-polyethylene glycol） （PLA-Hpr-PEG） copolymers were synthesized by direct melt copolymerization of D,L-lactic acid and 4-hydroxyproline with different feed amount of polyethylene glycol （PEG） 0.1%, 0.5%, 1% and 5%, respectively. The properties of these copolymers were characterized by using IR spectroscopy, proton nuclear magnetic resonance （1H-NMR） spectroscopy, gel permeation chromatography （GPC）, X-ray diffraction and differential scaning calorimetry （DSC）. PLA-Hpr-PEG are amorphous copolymers. Copolymers showed increasing water uptake capacity with increasing PEG percentage in the feed, which result in an increasing degradable rate in phosphate buffer solution （pH 7.4） at 37℃.
文摘采用Co_(3)O_(4)吸附脱除模拟柴油中的喹啉、吡啶或苯胺,考察了最佳吸附温度、吸附时间等条件,同时进行了吸附热力学和动力学研究;基于第一性原理对Co_(3)O_(4)晶胞进行相分析,对3种氮化物进行最高占据分子轨道(HOMO)-最低未占据分子轨道(LUMO)分析,计算了吸附构型的吸附能和最稳定吸附构型的Mulliken电荷转移与电子密度。结果表明:在15 mL模拟柴油中加入0.6 g Co_(3)O_(4),苯胺、吡啶、喹啉的最佳吸附温度分别为20、20和30℃,最佳吸附时间分别为30、30、40 min,吸附容量由大到小顺序均为苯胺>吡啶>喹啉。热力学与动力学分析表明,喹啉、吡啶、苯胺的吸附均更符合多分子层吸附的Freundlich模型和准二级动力学方程。HOMO-LUMO分析结果表明,Co_(3)O_(4)为电子接受体,3种氮化物为电子给予体,Co_(3)O_(4)对喹啉、吡啶的配位吸附结构最稳定,对苯胺的π络合吸附最稳定。电荷转移计算表明,苯胺、吡啶、喹啉向Co_(3)O_(4)团簇转移的电荷数分别为0.423、0.394、0.368,说明Co_(3)O_(4)吸附3种氮化物的吸附能力大小为苯胺>吡啶>喹啉;电子密度图结果表明,最稳定吸附结构中Co_(3)O_(4)与3种氮化物均形成了化学键。
