This is the first one that applies the Zisman critical surface tension technique successfully to textile materials. It was accomplished by carefully determination of the contact angle of fabric. The deviation caused b...This is the first one that applies the Zisman critical surface tension technique successfully to textile materials. It was accomplished by carefully determination of the contact angle of fabric. The deviation caused by the porous structure of the fabric will be taken into account. To do so, a Jens equation is applied, and the measured contact angles can be corrected. The surface porosity was determined by measurement and approximate calculation, and the chemical composition of the surface was characterized by means of attenuated total reflection Fourier-transform infrared(FTIR/ATR).展开更多
Zeolitic imidazolate framework-8(ZIF-8)is a typical filler used to fabricate mixed matrix membranes(MMMs)on account of its attractive advantage of high selective permeability for gas separation.However,the performance...Zeolitic imidazolate framework-8(ZIF-8)is a typical filler used to fabricate mixed matrix membranes(MMMs)on account of its attractive advantage of high selective permeability for gas separation.However,the performance is usually affected by filler aggregation due to strong interactions among fillers and weak interactions between the polymer and fillers,However,the performance is usually affected by filler aggregation due to strong interactions among fillers and weak interactions between the polymer and fillers,which will lead to a decrease of selectivity and the performance of gas separation will be strongly influenced.Herein,we modified ZIF-8 with 3-amino-1,2,4-triazole to obtain ZIF-8-NH_(2),Kapton polyamide acid was selected as the polymer matrix.Results showed that the ZIF-8-NH_(2)/Kapton MMMs has a good compatibility interface between ZIF-8 and Kapton because of the covalent bridging,even the filler loading up to 45%(mass).The 45%(mass)of ZIF-8-NH_(2)/Kapton membrane showed 297 barrer(1 barrer=10^(-10)10 cm^(3)·cm·cm^(-2)·s^(-1)·cmHg^(-1),1 cmHg=1333.22 Pa,standard temperature and pressure)of the permeability of H_(2)and 43.9 and 62.2 of selectivities for H_(2)/N_(2)and for H_(2)/CH_(4),respectively,which are beyond the upper limit of Robeson 2008.展开更多
Poly(ethylene terephthalate) (PET)/carbon black (CB) masterbatch was prepared by melt blending using a separate feeding technique and its homogeneous dispersion morphology was confirmed by transmission electron micros...Poly(ethylene terephthalate) (PET)/carbon black (CB) masterbatch was prepared by melt blending using a separate feeding technique and its homogeneous dispersion morphology was confirmed by transmission electron microscope (TEM). The Avrami and Hoffman-Lauritzen secondary nucleation theories were employed to analyze the effect of high CB content on crystallization kinetics of PET, providing theoretical support for the development of masterbatch with high content of functional components. The Avrami exponents,average values of n,for PET and PET/CB masterbatch are both greater than 3, which indicates three-dimensional growth of crystals. In addition,no significant evidence for regime transition of PET is found applying Hoffman-Lauritzen secondary nucleation theory,though such observations have been reported previously in the literature. Furthermore,appropriate U* value for PET is determined to be 12 800 J/mol. For PET/CB masterbatch,a transition from regime I to regime II around 225℃ is observed with appropriate U* value (12 800 J/mol) . This phenomenon is consistent with a transition point in plot of G versus Tc . The fold surface free energy σe (100. 3 mJ/m 2) of PET is much greater than that of PET/CB masterbatch (48. 3 mJ/m 2) ,which indicates heterogeneous nucleation effect of CB particles.展开更多
The effect of reverse pressure.on theological behavior has been studied. The apparatus is a capillary rheometer with counter pressure chamber being held at a high reverse pressure by means of a cock. The results show ...The effect of reverse pressure.on theological behavior has been studied. The apparatus is a capillary rheometer with counter pressure chamber being held at a high reverse pressure by means of a cock. The results show that with the increase in temperature, the shear viscosity of hydrophilic PET is reduced. It is different that the effect of temperature on shear viscosity is varied under the condition of all shear rates or all pressures, and the effect is more prominent at 50 MPa or at 216 s^-1. At the same time, the pressure coefficients decrease with increasing the shear rate and the temperature and tend to reach a constant value nearly at the temperature of 290 ℃.展开更多
The blend system composed of PET and thermotropic liquid crystal copolyester based on hydroxy benzoic acid, terephthalic acid, diacetylnaphthalene and PET was studied. The results indicated that LCP could play the rol...The blend system composed of PET and thermotropic liquid crystal copolyester based on hydroxy benzoic acid, terephthalic acid, diacetylnaphthalene and PET was studied. The results indicated that LCP could play the role of crystal nuclei. The introduction of LCP decreased the melt viscosity of the system and fibrillous structure could be formed in favor conditions.展开更多
A thermotropic liquid crystal copolyester resin based on p-hydroxybenzoic acid, 2, 6-naphthoic acid, hydroxyquinone and PET was synthesized by melt condensation and studied. The results based on DSC and X-ray diffract...A thermotropic liquid crystal copolyester resin based on p-hydroxybenzoic acid, 2, 6-naphthoic acid, hydroxyquinone and PET was synthesized by melt condensation and studied. The results based on DSC and X-ray diffraction indicated that there were a rapid and a slow crystallization processes for the copolyester at certain conditions. A critical temperature was suggested, below which the slow crystallization could hardly happen. Above the critical temperature the extent of the slow crystallization process depended not only on annealing temperature but also on the annealing time. A fine crystal structure with high melting point and narrow diffraction peak was formed under favorable conditions.展开更多
Polyglycolide (PGA) fibers applied as surgical sutures strongly depend on their microstructure. The structural evolution of PGA nascent fibers during single low-temperature stretching and segmented high-temperature st...Polyglycolide (PGA) fibers applied as surgical sutures strongly depend on their microstructure. The structural evolution of PGA nascent fibers during single low-temperature stretching and segmented high-temperature stretching was analyzed based on a combination of in situ WAXD/SAXS and DSC measurements. The results indicated that the hot stretching was conducive to the crystal perfection and the local fragmentation and recrystallization of the lamellar crystals may occur under stress induction. The single low-temperature stretching of PGA nascent fibers could be divided into three stages: the stretching of amorphous regions, stretch-induced crystallization and the stretching of crystalline regions. The elongation at break of the fibers can be substantially increased by adopting a segmented stretching method, and the high-temperature stretching can also significantly increase the crystallinity and orientation. The amorphous orientation peak appearing in the low-temperature stretching was gradually converted to crystallization peak during the heating process, which greatly improved the crystallinity and orientation of the fibers. High-temperature stretching compared with low-temperature stretching was more favorable for crystal perfection and structural evolution, where lamellar crystals underwent stress-induced fragmentation recrystallization to transform to fibrous crystals as the strain increased.展开更多
This article aimed to find a new way to transform the graphic image (drawing, photos, etc) to the pattern parameters of female apparel with raglan sleeve. The correlation and regressive analysis were used to the data ...This article aimed to find a new way to transform the graphic image (drawing, photos, etc) to the pattern parameters of female apparel with raglan sleeve. The correlation and regressive analysis were used to the data in order to find the existing laws between them. The practical examinations demonstrated the good predictability of equations established.展开更多
The mathematical description of clothes shape change is made by the example of a European female classical jacket. As objects of research graphic representations of female classical jackets have been taken from women&...The mathematical description of clothes shape change is made by the example of a European female classical jacket. As objects of research graphic representations of female classical jackets have been taken from women's fashion magazines of the middle XX-the beginnings of XXI centuries published in France, Germany, Russia, Poland,Italy, U.S.A. For visual identification of female jacket models of the different time we product the nomenclature of the quantitative parameters of the internal form with use of the chosen more important information points is developed,Revealing of objectively existing laws of jacket form constructions is carried out with use of correlative and regressive analyses. The system of a few linear equations for the description, constructions and comparisons of jacket form characteristics of the researched periods are received. Graphic forms of representation of possible zones for information points moving are offered. Using quantitative information about this parameters changed in the period with 1955 on 2002 received by means of our special instrument we proved the constant cyclic character of change them. Knowledge the common rules of change of the chosen form parameters allow us distributing the established lows to 10th of XXI century as a possible perspective direction in fashion trends for designers and sewing industry. Due to establishing rules that took place in forming European female jacket during latest 50 years almost we offered the instrument for predicting the main possible changes in composite-structural construction until lOth of XXI century。展开更多
Nanofiber carbon aerogels with 3D interconnected microfibrillar networks exhibit fascinating physical properties and present great application potential.However,it is still a challenge to fabricate superelastic nanofi...Nanofiber carbon aerogels with 3D interconnected microfibrillar networks exhibit fascinating physical properties and present great application potential.However,it is still a challenge to fabricate superelastic nanofiber carbon aerogels owing to their extremely dilute brittle interconnections and poor fiber toughness after carbonization.Herein,aramid nanofibers(ANF)/nanocellulose(CNF)dual-fibrous carbon aerogels are prepared,which exhibited supercompressibility and superelasticity due to the"skeleton-binder"synergistic effect of ANF and CNF and the design of in-plane micro-wrinkle honeycomb structure.The"skeleton-binder"synergistic effect improves interfacial interactions of nanofibers and optimizes the stress distribution of carbon aerogel.The highly ordered honeycomb structure with in-plane microwrinkles,formed by the bidirectional freezing and the difference in volume shrinkage during the carbonization between CNFs and ANFs,endows the CNF/ANF carbon aerogel with negative Poisson's ratio and high energy absorption capacity.These strategies significantly improve the overall mechanical properties of ANF/CNF carbon aerogel including the elasticity and fatigue resistance.As a result,the ultralight carbon aerogel(3.46 mg/cm^(3))exhibits excellent supercompression(undergoing an extreme strain of 95%)and elasticity(a stress retention up to 81.38% at 90% strain with 500 cycles and 96.15% at 50%strain with 10,000 cycles).The nanofiber carbon aerogel shows excellent multifunctional properties in flexible piezoresistive sensor and anisotropic thermal insulation materials,including a desirable sensitivity(as high as 48.74 kPa^(-1))and an instant response time(~40 ms),an anisotropy factor of 3.69 and an ultralow radial thermal conductivity(0.012 W m^(-1) K^(-1)).These properties make dual-fibrous carbon aerogels highly attractive in pressure sensors and thermal management applications.展开更多
文摘This is the first one that applies the Zisman critical surface tension technique successfully to textile materials. It was accomplished by carefully determination of the contact angle of fabric. The deviation caused by the porous structure of the fabric will be taken into account. To do so, a Jens equation is applied, and the measured contact angles can be corrected. The surface porosity was determined by measurement and approximate calculation, and the chemical composition of the surface was characterized by means of attenuated total reflection Fourier-transform infrared(FTIR/ATR).
基金funded by National Natural Science Foundation of China(22278023)Beijing Municipal Science and Technology Planning Project(Z221100002722002)+1 种基金Beijing Natural Science Foundation(2222015)the long-term from the Ministry of Finance and the Ministry of Education of China.
文摘Zeolitic imidazolate framework-8(ZIF-8)is a typical filler used to fabricate mixed matrix membranes(MMMs)on account of its attractive advantage of high selective permeability for gas separation.However,the performance is usually affected by filler aggregation due to strong interactions among fillers and weak interactions between the polymer and fillers,However,the performance is usually affected by filler aggregation due to strong interactions among fillers and weak interactions between the polymer and fillers,which will lead to a decrease of selectivity and the performance of gas separation will be strongly influenced.Herein,we modified ZIF-8 with 3-amino-1,2,4-triazole to obtain ZIF-8-NH_(2),Kapton polyamide acid was selected as the polymer matrix.Results showed that the ZIF-8-NH_(2)/Kapton MMMs has a good compatibility interface between ZIF-8 and Kapton because of the covalent bridging,even the filler loading up to 45%(mass).The 45%(mass)of ZIF-8-NH_(2)/Kapton membrane showed 297 barrer(1 barrer=10^(-10)10 cm^(3)·cm·cm^(-2)·s^(-1)·cmHg^(-1),1 cmHg=1333.22 Pa,standard temperature and pressure)of the permeability of H_(2)and 43.9 and 62.2 of selectivities for H_(2)/N_(2)and for H_(2)/CH_(4),respectively,which are beyond the upper limit of Robeson 2008.
文摘Poly(ethylene terephthalate) (PET)/carbon black (CB) masterbatch was prepared by melt blending using a separate feeding technique and its homogeneous dispersion morphology was confirmed by transmission electron microscope (TEM). The Avrami and Hoffman-Lauritzen secondary nucleation theories were employed to analyze the effect of high CB content on crystallization kinetics of PET, providing theoretical support for the development of masterbatch with high content of functional components. The Avrami exponents,average values of n,for PET and PET/CB masterbatch are both greater than 3, which indicates three-dimensional growth of crystals. In addition,no significant evidence for regime transition of PET is found applying Hoffman-Lauritzen secondary nucleation theory,though such observations have been reported previously in the literature. Furthermore,appropriate U* value for PET is determined to be 12 800 J/mol. For PET/CB masterbatch,a transition from regime I to regime II around 225℃ is observed with appropriate U* value (12 800 J/mol) . This phenomenon is consistent with a transition point in plot of G versus Tc . The fold surface free energy σe (100. 3 mJ/m 2) of PET is much greater than that of PET/CB masterbatch (48. 3 mJ/m 2) ,which indicates heterogeneous nucleation effect of CB particles.
基金financially supported by the National "Twelfth Five-Year" Plan for Science&Technology(2011BAE05B00)the State Key Laboratory of Hollow Fiber Membrane Materials and Processes
文摘The effect of reverse pressure.on theological behavior has been studied. The apparatus is a capillary rheometer with counter pressure chamber being held at a high reverse pressure by means of a cock. The results show that with the increase in temperature, the shear viscosity of hydrophilic PET is reduced. It is different that the effect of temperature on shear viscosity is varied under the condition of all shear rates or all pressures, and the effect is more prominent at 50 MPa or at 216 s^-1. At the same time, the pressure coefficients decrease with increasing the shear rate and the temperature and tend to reach a constant value nearly at the temperature of 290 ℃.
基金Projects supported by the National Natural Science Foundation of China and Polymer Physics Laboratory (Beijing), Academia Sinica.
文摘The blend system composed of PET and thermotropic liquid crystal copolyester based on hydroxy benzoic acid, terephthalic acid, diacetylnaphthalene and PET was studied. The results indicated that LCP could play the role of crystal nuclei. The introduction of LCP decreased the melt viscosity of the system and fibrillous structure could be formed in favor conditions.
基金Projects supported by the National Natural Science Foundation of China and Polymer Physics Laboratory (Beijing), Academia Sinica
文摘A thermotropic liquid crystal copolyester resin based on p-hydroxybenzoic acid, 2, 6-naphthoic acid, hydroxyquinone and PET was synthesized by melt condensation and studied. The results based on DSC and X-ray diffraction indicated that there were a rapid and a slow crystallization processes for the copolyester at certain conditions. A critical temperature was suggested, below which the slow crystallization could hardly happen. Above the critical temperature the extent of the slow crystallization process depended not only on annealing temperature but also on the annealing time. A fine crystal structure with high melting point and narrow diffraction peak was formed under favorable conditions.
基金financially supported by the National Natural Science Foundation of China (Nos. 51973097 and 52173021)the Open Fund of State Key Laboratory of Biobased Fiber Manufacturing Technology (No. SKL202207)
文摘Polyglycolide (PGA) fibers applied as surgical sutures strongly depend on their microstructure. The structural evolution of PGA nascent fibers during single low-temperature stretching and segmented high-temperature stretching was analyzed based on a combination of in situ WAXD/SAXS and DSC measurements. The results indicated that the hot stretching was conducive to the crystal perfection and the local fragmentation and recrystallization of the lamellar crystals may occur under stress induction. The single low-temperature stretching of PGA nascent fibers could be divided into three stages: the stretching of amorphous regions, stretch-induced crystallization and the stretching of crystalline regions. The elongation at break of the fibers can be substantially increased by adopting a segmented stretching method, and the high-temperature stretching can also significantly increase the crystallinity and orientation. The amorphous orientation peak appearing in the low-temperature stretching was gradually converted to crystallization peak during the heating process, which greatly improved the crystallinity and orientation of the fibers. High-temperature stretching compared with low-temperature stretching was more favorable for crystal perfection and structural evolution, where lamellar crystals underwent stress-induced fragmentation recrystallization to transform to fibrous crystals as the strain increased.
文摘This article aimed to find a new way to transform the graphic image (drawing, photos, etc) to the pattern parameters of female apparel with raglan sleeve. The correlation and regressive analysis were used to the data in order to find the existing laws between them. The practical examinations demonstrated the good predictability of equations established.
文摘The mathematical description of clothes shape change is made by the example of a European female classical jacket. As objects of research graphic representations of female classical jackets have been taken from women's fashion magazines of the middle XX-the beginnings of XXI centuries published in France, Germany, Russia, Poland,Italy, U.S.A. For visual identification of female jacket models of the different time we product the nomenclature of the quantitative parameters of the internal form with use of the chosen more important information points is developed,Revealing of objectively existing laws of jacket form constructions is carried out with use of correlative and regressive analyses. The system of a few linear equations for the description, constructions and comparisons of jacket form characteristics of the researched periods are received. Graphic forms of representation of possible zones for information points moving are offered. Using quantitative information about this parameters changed in the period with 1955 on 2002 received by means of our special instrument we proved the constant cyclic character of change them. Knowledge the common rules of change of the chosen form parameters allow us distributing the established lows to 10th of XXI century as a possible perspective direction in fashion trends for designers and sewing industry. Due to establishing rules that took place in forming European female jacket during latest 50 years almost we offered the instrument for predicting the main possible changes in composite-structural construction until lOth of XXI century。
文摘Nanofiber carbon aerogels with 3D interconnected microfibrillar networks exhibit fascinating physical properties and present great application potential.However,it is still a challenge to fabricate superelastic nanofiber carbon aerogels owing to their extremely dilute brittle interconnections and poor fiber toughness after carbonization.Herein,aramid nanofibers(ANF)/nanocellulose(CNF)dual-fibrous carbon aerogels are prepared,which exhibited supercompressibility and superelasticity due to the"skeleton-binder"synergistic effect of ANF and CNF and the design of in-plane micro-wrinkle honeycomb structure.The"skeleton-binder"synergistic effect improves interfacial interactions of nanofibers and optimizes the stress distribution of carbon aerogel.The highly ordered honeycomb structure with in-plane microwrinkles,formed by the bidirectional freezing and the difference in volume shrinkage during the carbonization between CNFs and ANFs,endows the CNF/ANF carbon aerogel with negative Poisson's ratio and high energy absorption capacity.These strategies significantly improve the overall mechanical properties of ANF/CNF carbon aerogel including the elasticity and fatigue resistance.As a result,the ultralight carbon aerogel(3.46 mg/cm^(3))exhibits excellent supercompression(undergoing an extreme strain of 95%)and elasticity(a stress retention up to 81.38% at 90% strain with 500 cycles and 96.15% at 50%strain with 10,000 cycles).The nanofiber carbon aerogel shows excellent multifunctional properties in flexible piezoresistive sensor and anisotropic thermal insulation materials,including a desirable sensitivity(as high as 48.74 kPa^(-1))and an instant response time(~40 ms),an anisotropy factor of 3.69 and an ultralow radial thermal conductivity(0.012 W m^(-1) K^(-1)).These properties make dual-fibrous carbon aerogels highly attractive in pressure sensors and thermal management applications.
