The poor thermal stability and high sensitivity severely hinder the practical application of hexanitrohexaazaisowurtzitane(CL-20).Herein,a kind of novel core@double-shell CL-20 based energetic composites were fabricat...The poor thermal stability and high sensitivity severely hinder the practical application of hexanitrohexaazaisowurtzitane(CL-20).Herein,a kind of novel core@double-shell CL-20 based energetic composites were fabricated to address the above issues.The coordination complexes which consist of natural polyphenol tannic acid(TA) and Fe~Ⅲ were chosen to construct the inner shell,while the graphene sheets were used to build the outer shell.The resulting CL-20/TA-Fe~Ⅲ/graphene composites exhibited simultaneously improved thermal stability and safety performance with only 1 wt% double-shell content,which should be ascribed to the intense physical encapsulation effect from inner shell combined with the desensitization effect of carbon nano-materials from outer shell.The phase transition(ε to γ) temperature increased from 173.70 ℃ of pure CL-20 to 191.87℃ of CL-20/TA-Fe~Ⅲ/graphene composites.Meanwhile,the characteristic drop height(H_(50)) dramatically increased from 14.7 cm of pure CL-20 to112.8 cm of CL-20/TA-Fe~Ⅲ/graphene composites,indicating much superior safety performance after the construction of the double-shell structure.In general,this work has provided an effective and versatile strategy to conquer the thermal stability and safety issues of CL-20 and contributes to the future application of high energy density energetic materials.展开更多
Attributed to the intense development and complexity in electronic devices,energy dissipation is becoming more essential nowadays.The carbonaceous materials particularly graphene(Gr)-based thermal interface materials(...Attributed to the intense development and complexity in electronic devices,energy dissipation is becoming more essential nowadays.The carbonaceous materials particularly graphene(Gr)-based thermal interface materials(TIMs)are exceptional in heat management.However,because of the anisotropic behavior of Gr in composites,the TIMs having outstanding through-plane thermal conductivity(┴TC)are needed to fulfill the upcoming innovation in numerous devices.In order to achieve this,herein,nano-urethane linkage-based modified Gr and carbon fibers architecture termed as nanourethane linkage(NUL)-Gr/carbon fibers(CFs)is fabricated.Wherein,toluene diisocyanate is utilized to develop a novel but simple NUL to shape a new interface between graphene sheets.Interestingly,the prepared composite of NUL-Gr/CFs with polyvinylidene fluoride matrix shows outstanding performance in heat management.Owing to the unique structure of NUL-Gr/CFs,an unprecedented value of┴TC(~7.96 W·m^–1·K^–1)is achieved at a low filler fraction of 13.8 wt.%which translates into an improvement of^3,980%of pristine polymer.The achieved outcomes elucidate the significance of the covalent interaction between graphene sheets as well as strong bonding among graphene and matrix in the composites and manifest the potential of proposed NUL-Gr/CFs architecture for practical applications.展开更多
基金financially supported by the National Natural Science Foundation of China (Grant No. 22275173)the Open Project of State Key Laboratory of Environment-friendly Energy Materials (Grant No. 22kfhg10)。
文摘The poor thermal stability and high sensitivity severely hinder the practical application of hexanitrohexaazaisowurtzitane(CL-20).Herein,a kind of novel core@double-shell CL-20 based energetic composites were fabricated to address the above issues.The coordination complexes which consist of natural polyphenol tannic acid(TA) and Fe~Ⅲ were chosen to construct the inner shell,while the graphene sheets were used to build the outer shell.The resulting CL-20/TA-Fe~Ⅲ/graphene composites exhibited simultaneously improved thermal stability and safety performance with only 1 wt% double-shell content,which should be ascribed to the intense physical encapsulation effect from inner shell combined with the desensitization effect of carbon nano-materials from outer shell.The phase transition(ε to γ) temperature increased from 173.70 ℃ of pure CL-20 to 191.87℃ of CL-20/TA-Fe~Ⅲ/graphene composites.Meanwhile,the characteristic drop height(H_(50)) dramatically increased from 14.7 cm of pure CL-20 to112.8 cm of CL-20/TA-Fe~Ⅲ/graphene composites,indicating much superior safety performance after the construction of the double-shell structure.In general,this work has provided an effective and versatile strategy to conquer the thermal stability and safety issues of CL-20 and contributes to the future application of high energy density energetic materials.
基金the Nature Science Associate Foundation(NSAF)(No.U1730103)the National Natural Science Foundation of China(NSFC)(No.11672002)。
文摘Attributed to the intense development and complexity in electronic devices,energy dissipation is becoming more essential nowadays.The carbonaceous materials particularly graphene(Gr)-based thermal interface materials(TIMs)are exceptional in heat management.However,because of the anisotropic behavior of Gr in composites,the TIMs having outstanding through-plane thermal conductivity(┴TC)are needed to fulfill the upcoming innovation in numerous devices.In order to achieve this,herein,nano-urethane linkage-based modified Gr and carbon fibers architecture termed as nanourethane linkage(NUL)-Gr/carbon fibers(CFs)is fabricated.Wherein,toluene diisocyanate is utilized to develop a novel but simple NUL to shape a new interface between graphene sheets.Interestingly,the prepared composite of NUL-Gr/CFs with polyvinylidene fluoride matrix shows outstanding performance in heat management.Owing to the unique structure of NUL-Gr/CFs,an unprecedented value of┴TC(~7.96 W·m^–1·K^–1)is achieved at a low filler fraction of 13.8 wt.%which translates into an improvement of^3,980%of pristine polymer.The achieved outcomes elucidate the significance of the covalent interaction between graphene sheets as well as strong bonding among graphene and matrix in the composites and manifest the potential of proposed NUL-Gr/CFs architecture for practical applications.
