Near-infrared(NIR)light-responsive shape memory polymers(SMPs)show great promise for biomedical applications,but conventional photothermal agents suffer from high cost,complex preparation,or poor biocompatibility,whil...Near-infrared(NIR)light-responsive shape memory polymers(SMPs)show great promise for biomedical applications,but conventional photothermal agents suffer from high cost,complex preparation,or poor biocompatibility,while lignin-based alternatives exhibit insufficient photothermal conversion efficiency.Herein,we developed a novel strategy to enhance photothermal performance of lignin through sequential demethylation modification and Fe^(3+)complexation for constructing NIR light responsive SMPs.Dealkaline lignin(DL)was first demethylated using iodocyclohexane to produce demethylated lignin(DDL)with increased catechol content,which was then incorporated into polycaprolactone-based polyurethane synthesis followed by Fe^(3+)complexation.Results showed that DDL-Fe^(3+)complexes have significantly enhanced photothermal conversion performance,and the resulting PU-DDL+Fe^(3+)polyurethane with 0.5 wt%DDL content demonstrated a temperature increases of 39.8℃under 0.33 W·cm-2808 nm NIR irradiation.This excellent photothermal performance enables the shape-fixed PU-DDL+Fe^(3+)polyurethane to rapidly recover to its initial shape under NIR light irradiation.Additionally,PU-DDL+Fe^(3+)polyurethane exhibits good mechanical properties and biocompatibility,demonstrating significant biomedical application potential.展开更多
The synthesis of polyurethanes(PUs)from the reaction of low molecular weight poly(ethylene carbonate)diol(PECD)is rarely investigated.This work reports a novel PU with excellent mechanical properties from the solution...The synthesis of polyurethanes(PUs)from the reaction of low molecular weight poly(ethylene carbonate)diol(PECD)is rarely investigated.This work reports a novel PU with excellent mechanical properties from the solution polymerization of 4,4-diphenylmethane diisocyanate(MDI)with PECD that was derived from the copolymerization of carbon dioxide(CO_(2))and ethylene oxide(EO).The tensile strength,the elongation at break and 300%constant tensile strength of the PECD-PU were up to 66±2 MPa,880%±50%and 13 MPa,respectively,higher than the control PUs from the reaction of MDI with commercial polyethers or polyesters.The PECD-PU with high CO_(2) carbonate content exhibited good solvent resistance and chemical stability.Of importance,the mechanical properties and chemical resistance of PECD-PU were significantly enhanced with the increasing content of CO_(2),i.e.,the carbonate unit in PECD.This work provides comprehensive properties of PECD-derived PUs,indicating that PECD is a competitive precursor for the preparation of PU and has broad application prospects.展开更多
密封技术是压缩空气储能(compressed air energy storage,CAES)人工硐室储气库建设的关键技术之一,其密封材料的选择至关重要。为了验证聚氨酯类聚合物砂浆(polyurethane polymer mortar,PPM)作为CAES人工硐室储气库密封材料的可行性,对...密封技术是压缩空气储能(compressed air energy storage,CAES)人工硐室储气库建设的关键技术之一,其密封材料的选择至关重要。为了验证聚氨酯类聚合物砂浆(polyurethane polymer mortar,PPM)作为CAES人工硐室储气库密封材料的可行性,对PPM进行了气体渗透性试验和力学试验,分析其气密性能和强度与变形性能,并利用FLAC^(3D)软件分析了PPM密封层结构的受力特性与气体泄漏率。结果表明:PPM具有极佳的气密性能,其本质渗透率量级可达到10^(-20)~10^(-22) m^(2),可满足CAES密封层的密封要求。PPM的拉伸性能优异,弹性模量低,变形能力强,与混凝土之间具有自黏能力。当PPM本质渗透率为10^(-19) m^(2)时,储气库渗漏量为0.215%,满足1 d内空气质量允许泄漏率的要求。由于PPM的弹性模量低,使得PPM密封层的计算环向应力均表现为压应力;最大环向拉应变仅有1.15%~1.20%,远小于其极限拉伸应变,可有效防治密封层产生拉伸破坏。由此可见,PPM在气渗和力学指标上均可满足CAES密封材料的性能要求。展开更多
基金supported by the National Natural Science Foundation of China(Nos.51603005,52403186 and 52573150)Fujian Provincial Natural Science Foundation of China(No.2024J011447)+1 种基金Natural Science Foundation of Xiamen,China(No.3502Z20227305)the Postdoctoral Fellowship Program of CPSF(No.GZC20240095)。
文摘Near-infrared(NIR)light-responsive shape memory polymers(SMPs)show great promise for biomedical applications,but conventional photothermal agents suffer from high cost,complex preparation,or poor biocompatibility,while lignin-based alternatives exhibit insufficient photothermal conversion efficiency.Herein,we developed a novel strategy to enhance photothermal performance of lignin through sequential demethylation modification and Fe^(3+)complexation for constructing NIR light responsive SMPs.Dealkaline lignin(DL)was first demethylated using iodocyclohexane to produce demethylated lignin(DDL)with increased catechol content,which was then incorporated into polycaprolactone-based polyurethane synthesis followed by Fe^(3+)complexation.Results showed that DDL-Fe^(3+)complexes have significantly enhanced photothermal conversion performance,and the resulting PU-DDL+Fe^(3+)polyurethane with 0.5 wt%DDL content demonstrated a temperature increases of 39.8℃under 0.33 W·cm-2808 nm NIR irradiation.This excellent photothermal performance enables the shape-fixed PU-DDL+Fe^(3+)polyurethane to rapidly recover to its initial shape under NIR light irradiation.Additionally,PU-DDL+Fe^(3+)polyurethane exhibits good mechanical properties and biocompatibility,demonstrating significant biomedical application potential.
基金financially supported by the Maoming Science and Technology Bureau(No.2022DZXHT007)。
文摘The synthesis of polyurethanes(PUs)from the reaction of low molecular weight poly(ethylene carbonate)diol(PECD)is rarely investigated.This work reports a novel PU with excellent mechanical properties from the solution polymerization of 4,4-diphenylmethane diisocyanate(MDI)with PECD that was derived from the copolymerization of carbon dioxide(CO_(2))and ethylene oxide(EO).The tensile strength,the elongation at break and 300%constant tensile strength of the PECD-PU were up to 66±2 MPa,880%±50%and 13 MPa,respectively,higher than the control PUs from the reaction of MDI with commercial polyethers or polyesters.The PECD-PU with high CO_(2) carbonate content exhibited good solvent resistance and chemical stability.Of importance,the mechanical properties and chemical resistance of PECD-PU were significantly enhanced with the increasing content of CO_(2),i.e.,the carbonate unit in PECD.This work provides comprehensive properties of PECD-derived PUs,indicating that PECD is a competitive precursor for the preparation of PU and has broad application prospects.
文摘密封技术是压缩空气储能(compressed air energy storage,CAES)人工硐室储气库建设的关键技术之一,其密封材料的选择至关重要。为了验证聚氨酯类聚合物砂浆(polyurethane polymer mortar,PPM)作为CAES人工硐室储气库密封材料的可行性,对PPM进行了气体渗透性试验和力学试验,分析其气密性能和强度与变形性能,并利用FLAC^(3D)软件分析了PPM密封层结构的受力特性与气体泄漏率。结果表明:PPM具有极佳的气密性能,其本质渗透率量级可达到10^(-20)~10^(-22) m^(2),可满足CAES密封层的密封要求。PPM的拉伸性能优异,弹性模量低,变形能力强,与混凝土之间具有自黏能力。当PPM本质渗透率为10^(-19) m^(2)时,储气库渗漏量为0.215%,满足1 d内空气质量允许泄漏率的要求。由于PPM的弹性模量低,使得PPM密封层的计算环向应力均表现为压应力;最大环向拉应变仅有1.15%~1.20%,远小于其极限拉伸应变,可有效防治密封层产生拉伸破坏。由此可见,PPM在气渗和力学指标上均可满足CAES密封材料的性能要求。
