The development of adhesive technology is gaining increasing attention in machinery,electronics,aviation,and other fields.However,traditional adhesives are difficult to be peeled and removed after cross-linking and cu...The development of adhesive technology is gaining increasing attention in machinery,electronics,aviation,and other fields.However,traditional adhesives are difficult to be peeled and removed after cross-linking and curing due to the limited solubility in common solvents,which causes pollution and damage to the surface of the adherend.In this work,we synthesized random hyperbranched polyamide-amine hot melt adhesives through Michael addition of 1,8-octanediamine and N,N’-methylene diacrylamide(ODA-RHP HMA).Owing to the presence of various polar groups,ODA-RHP HMA exhibited robust lap shear strength to different substrates,including glass(6.6 MPa),ceramics(10.3 MPa),steel(11.5 MPa),and aluminum(11.8 MPa).Due to the hydrogen bonds in ODA-RHP,the HMA demonstrated intrinsic self-healing ability,which can be used repeatedly when being subjected to cyclic heating and cooling.Since ODA-RHP HMA can be swollen or dissolved in ethanol,the adhesives can be easily removed through erasing.In addition,ODA-RHP exhibited aggregation-induced luminescence due to the tertiary amine structure in the molecular structure of ODA-RHP,which can be used in the field of cultural relics restoration.展开更多
X-ray photon correlation spectroscopy(XPCS)has emerged as a powerful tool for probing the nanoscale dynamics of soft condensed matter and strongly correlated materials owing to its high spatial resolution and penetrat...X-ray photon correlation spectroscopy(XPCS)has emerged as a powerful tool for probing the nanoscale dynamics of soft condensed matter and strongly correlated materials owing to its high spatial resolution and penetration capabilities.This technique requires high brilliance and beam coherence,which are not directly available at modern synchrotron beamlines in China.To facilitate future XPCS experiments,we modified the optical setup of the newly commissioned BL10U1 USAXS beamline at the Shanghai Synchrotron Radiation Facility(SSRF).Subsequently,we performed XPCS measurements on silica suspensions in glycerol,which were opaque owing to their high concentrations.Images were collected using a high frame rate area detector.A comprehensive analysis was performed,yielding correlation functions and several key dynamic parameters.All the results were consistent with the theory of Brownian motion and demonstrated the feasibility of XPCS at SSRF.Finally,by carefully optimizing the setup and analyzing the algorithms,we achieved a time resolution of 2 ms,which enabled the characterization of millisecond dynamics in opaque systems.展开更多
Sulfur-containing dynamic polymers had attracted significant attention due to their unique chemical structures with high reversibility.Utilizating sulfur, an inexpensive industrial waste product, to synthesize dynamic...Sulfur-containing dynamic polymers had attracted significant attention due to their unique chemical structures with high reversibility.Utilizating sulfur, an inexpensive industrial waste product, to synthesize dynamic polysulfide polymers through reverse vulcanization has been a notable approach. However, this method required high temperatures and resulted in the release of unpleasant oders. In this study, we presented a robust method for the preparation of sulfur-rich polymers with dynamic polysulfide bonds from elemental sulfur and inexpensive epoxide monomers via a one-pot strategy at the mild room temperature. Different types of polysulfide molecules and polymers were synthesized by reacting various epoxide compounds with sulfur, along with the investigation of their structures and dynamic behaviors. It was noteworthy that the obatined polymers prepared from m-(2,3-epoxypropoxy)-N,N-bis(2,3-epoxypropyl)aniline and elemental sulfur exhibit multiple dynamic behaviors, including polysulfide metathesis and polysulfide-thiol exchange, enabling their rapid stress relaxation, self-healing, reprocessing and degradable properties of the cross-linked polymer. More importantly, the hydroxyl groups at the side chains from epoxide ring opening exhibited potential transesterification. This work provided a facile strategy for designing dynamic sulfur-rich polymers via a mild synthesis route.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51873170 and 11732012)the National Key R&D Program of China(No.2019YFA0706801)+1 种基金the Key Laboratory Construction Program of Xi'an Science and Technology Bureau(No.201805056ZD7CG40)the One Hundred Talents Program of Shaanxi Province and Shaanxi International Science and Technology Cooperation Program Project(No.2020KW-062)。
文摘The development of adhesive technology is gaining increasing attention in machinery,electronics,aviation,and other fields.However,traditional adhesives are difficult to be peeled and removed after cross-linking and curing due to the limited solubility in common solvents,which causes pollution and damage to the surface of the adherend.In this work,we synthesized random hyperbranched polyamide-amine hot melt adhesives through Michael addition of 1,8-octanediamine and N,N’-methylene diacrylamide(ODA-RHP HMA).Owing to the presence of various polar groups,ODA-RHP HMA exhibited robust lap shear strength to different substrates,including glass(6.6 MPa),ceramics(10.3 MPa),steel(11.5 MPa),and aluminum(11.8 MPa).Due to the hydrogen bonds in ODA-RHP,the HMA demonstrated intrinsic self-healing ability,which can be used repeatedly when being subjected to cyclic heating and cooling.Since ODA-RHP HMA can be swollen or dissolved in ethanol,the adhesives can be easily removed through erasing.In addition,ODA-RHP exhibited aggregation-induced luminescence due to the tertiary amine structure in the molecular structure of ODA-RHP,which can be used in the field of cultural relics restoration.
基金This work was supported by National Natural Science Foundation of China(No.12075304)Natural Science Foundation of Shanghai(No.22ZR1442100)National Key Research and Development Program of China(No.2022YFB3503904).
文摘X-ray photon correlation spectroscopy(XPCS)has emerged as a powerful tool for probing the nanoscale dynamics of soft condensed matter and strongly correlated materials owing to its high spatial resolution and penetration capabilities.This technique requires high brilliance and beam coherence,which are not directly available at modern synchrotron beamlines in China.To facilitate future XPCS experiments,we modified the optical setup of the newly commissioned BL10U1 USAXS beamline at the Shanghai Synchrotron Radiation Facility(SSRF).Subsequently,we performed XPCS measurements on silica suspensions in glycerol,which were opaque owing to their high concentrations.Images were collected using a high frame rate area detector.A comprehensive analysis was performed,yielding correlation functions and several key dynamic parameters.All the results were consistent with the theory of Brownian motion and demonstrated the feasibility of XPCS at SSRF.Finally,by carefully optimizing the setup and analyzing the algorithms,we achieved a time resolution of 2 ms,which enabled the characterization of millisecond dynamics in opaque systems.
基金financially supported by the State Key R&D Program of China (No. 2019YFA0706801)the National Natural Science Foundation of China (No. 52173079)the Fundamental Research Funds for the Central Universities (Nos. xtr052023001 and xzy022024024)。
文摘Sulfur-containing dynamic polymers had attracted significant attention due to their unique chemical structures with high reversibility.Utilizating sulfur, an inexpensive industrial waste product, to synthesize dynamic polysulfide polymers through reverse vulcanization has been a notable approach. However, this method required high temperatures and resulted in the release of unpleasant oders. In this study, we presented a robust method for the preparation of sulfur-rich polymers with dynamic polysulfide bonds from elemental sulfur and inexpensive epoxide monomers via a one-pot strategy at the mild room temperature. Different types of polysulfide molecules and polymers were synthesized by reacting various epoxide compounds with sulfur, along with the investigation of their structures and dynamic behaviors. It was noteworthy that the obatined polymers prepared from m-(2,3-epoxypropoxy)-N,N-bis(2,3-epoxypropyl)aniline and elemental sulfur exhibit multiple dynamic behaviors, including polysulfide metathesis and polysulfide-thiol exchange, enabling their rapid stress relaxation, self-healing, reprocessing and degradable properties of the cross-linked polymer. More importantly, the hydroxyl groups at the side chains from epoxide ring opening exhibited potential transesterification. This work provided a facile strategy for designing dynamic sulfur-rich polymers via a mild synthesis route.
