Dendrimers are the subject of intense attention recently because of their anticipated potentialities and the peculiar structural properties.A novel synthetic route for the preparation of functionalized dendrons built ...Dendrimers are the subject of intense attention recently because of their anticipated potentialities and the peculiar structural properties.A novel synthetic route for the preparation of functionalized dendrons built on the 1,3,5-benzenetricarboxaldehyde core and endowed with a periphery of pentaerythritol groups has been developed.1,3,5-Tri（2,6-dioxa-4,4-dihydroxymethyl cyclohexyl） benzene（1） was synthesized by the condensation of 1,3,5-benzenetricarboxaldehyde with pentaerythritol in the presence of hot CHCl3 and p-methyl benzene sulfonic acid with 55% yield.By turning 1,3,5-benzenetricarboxaldehyde into its trioxime,it was protected to decrease the cross-linked reaction with compound 1 both including many groups.The reaction of compound 1 with 1,3,5-benzenetricarboxaldehyde trioxime and pentaerythritol afforded 1,3,5-tri{3-[2,4,8,10 -tetra-oxa-9(3,5-di（2,6-dioxa-4,4-dihydroxymethylcyclohexyl） phenyl]spiro\undecyl}benzene（2） by using I2 as the catalyst,and the yield was 25.2%.Product 2 and its intermediates were identified by IR,1H NMR,MS spectra and elemental analysis.展开更多
Electrospinning is a simple technique used to fabricate polymeric nano-fibrous membranes.These nano-fibers have found a wide range of valuable applications in the biomedical field.However,it has not been utilized with...Electrospinning is a simple technique used to fabricate polymeric nano-fibrous membranes.These nano-fibers have found a wide range of valuable applications in the biomedical field.However,it has not been utilized with solid high explosives yet.Herein,the electrospinning technique has been used to fabricate polystyrene(PS)/1,3,5-trinitro-1,3,5-triazinane(RDX)composite nanofibers.The governed electrospinning parameters,voltage,distance from the collector,flow rate,mandrel rotating speed,time,and solution concentration,that greatly affect the morphology of the obtained nanofibers were optimized.The fabricated PS/RDX nano-fibers were characterized using scanning electron microscopy(SEM),X-ray diffractometer(XRD),and Fourier Transform Infrared(FTIR)spectroscopy.The impact and friction sensitivities of PS/RDX were also measured.The thermal behavior of the prepared composite and the pure materials were studied by the thermal gravimetric analysis technique(TGA).SEM results proved the fabrication of PS/RDX fibers in the nano-size via electrospinning.FTIR spectroscopy confirmed the existence of the characteristic functional groups of both PS and RDX in the composite nano-fibers.XRD sharp peaks showed the conversion of amorphous PS into crystalline shape via electrospinning and also confirmed the formation of PS/RDX composite.The PS fibers absorbed the heat and increased the onset decomposition of the pure RDX from 181.5 to 200.7℃in the case of PS/RDX fibers.Interestingly,PS/RDX nano-fibers showed the relatively low impact and friction sensitivities of 100 J and 360 N respectively.These results could introduce PS/RDX nanofibrous composite in the field of explosives detection with high levels of safety.展开更多
文摘Dendrimers are the subject of intense attention recently because of their anticipated potentialities and the peculiar structural properties.A novel synthetic route for the preparation of functionalized dendrons built on the 1,3,5-benzenetricarboxaldehyde core and endowed with a periphery of pentaerythritol groups has been developed.1,3,5-Tri（2,6-dioxa-4,4-dihydroxymethyl cyclohexyl） benzene（1） was synthesized by the condensation of 1,3,5-benzenetricarboxaldehyde with pentaerythritol in the presence of hot CHCl3 and p-methyl benzene sulfonic acid with 55% yield.By turning 1,3,5-benzenetricarboxaldehyde into its trioxime,it was protected to decrease the cross-linked reaction with compound 1 both including many groups.The reaction of compound 1 with 1,3,5-benzenetricarboxaldehyde trioxime and pentaerythritol afforded 1,3,5-tri{3-[2,4,8,10 -tetra-oxa-9(3,5-di（2,6-dioxa-4,4-dihydroxymethylcyclohexyl） phenyl]spiro\undecyl}benzene（2） by using I2 as the catalyst,and the yield was 25.2%.Product 2 and its intermediates were identified by IR,1H NMR,MS spectra and elemental analysis.
文摘Electrospinning is a simple technique used to fabricate polymeric nano-fibrous membranes.These nano-fibers have found a wide range of valuable applications in the biomedical field.However,it has not been utilized with solid high explosives yet.Herein,the electrospinning technique has been used to fabricate polystyrene(PS)/1,3,5-trinitro-1,3,5-triazinane(RDX)composite nanofibers.The governed electrospinning parameters,voltage,distance from the collector,flow rate,mandrel rotating speed,time,and solution concentration,that greatly affect the morphology of the obtained nanofibers were optimized.The fabricated PS/RDX nano-fibers were characterized using scanning electron microscopy(SEM),X-ray diffractometer(XRD),and Fourier Transform Infrared(FTIR)spectroscopy.The impact and friction sensitivities of PS/RDX were also measured.The thermal behavior of the prepared composite and the pure materials were studied by the thermal gravimetric analysis technique(TGA).SEM results proved the fabrication of PS/RDX fibers in the nano-size via electrospinning.FTIR spectroscopy confirmed the existence of the characteristic functional groups of both PS and RDX in the composite nano-fibers.XRD sharp peaks showed the conversion of amorphous PS into crystalline shape via electrospinning and also confirmed the formation of PS/RDX composite.The PS fibers absorbed the heat and increased the onset decomposition of the pure RDX from 181.5 to 200.7℃in the case of PS/RDX fibers.Interestingly,PS/RDX nano-fibers showed the relatively low impact and friction sensitivities of 100 J and 360 N respectively.These results could introduce PS/RDX nanofibrous composite in the field of explosives detection with high levels of safety.
