A V-shaped nylon net fence installed in 1990 on top of the Mogao Grottoes is shown to be effectively resisting aeolian sand damage to the grottoes. The structure guides and causes deposition of sand from westerly wind...A V-shaped nylon net fence installed in 1990 on top of the Mogao Grottoes is shown to be effectively resisting aeolian sand damage to the grottoes. The structure guides and causes deposition of sand from westerly wind (the primary hard wind), but to some extent hinders the inverse function of easterly wind carrying sand away from the grottoes toward Mount Mingsha. The gobi side by the fence experiences higher wind speed, so that on which are easily formed undercutting pits, and the deposited sands on it generally form double-peak structures due to abundant sand sources. If the earth surface characteristics in gobi areas by both sides of the fence are quite varied, the erosion and deposition features of the accumulating sand section are similar in different seasons; however, if the earth surface characteristics are similar, the features become irregular in different seasons. Sand depositions with long slope feet are formed along the south and north sides of V-shaped nylon net fence. Disrupted by strong westerly wind and northwesterly wind, sand accumulations by north of the fence are in form of single peaks. Although the operation duration of the V-shaped nylon net fence has exceeded its design life (10 years), our observations indicate that it is still effective in reducing wind-driven sand damages to the Mogao Grottoes, so it should not be withdrawn.展开更多
Considerable progress has been made in recent years to the development of sustainable polymers from bio-based feedstocks.In this study,100%bio-based nylons were prepared via an integrated chemical and biological proce...Considerable progress has been made in recent years to the development of sustainable polymers from bio-based feedstocks.In this study,100%bio-based nylons were prepared via an integrated chemical and biological process from lignocellulose.These novel nylons were obtained by the melt polymerization of 3-propyladipic acid derived from lignin and 1,5-pentenediamine/1,4-butanediamine derived from carbohydrate sugar.Central to the concept is a three-step noble metal free catalytic chemical funnelling sequence(Raney Ni mediated reductive catalytic fractionation-reductive funnelling-oxidative funnelling),which allowed for obtaining a single component 3-propyladipic acid from lignin with high efficiency.The structural and thermodynamic properties of the obtained nylons have been systematically investigated,and thus obtained transparent bio-based nylons exhibited higher Mw(>32,000)and excellent thermal stability(Td5%>265℃).Considering their moderate Tg and good melt strength,these transparent bio-based nylons could serve as promising functional additives or temperature-responsive materials.展开更多
Migdal Haemek,Israel,April 2,2024.NILIT,the global market leader,and a producer of high quality Nylon 6.6 for apparel and owner of the SENSIL?brand,introduces SENSIL?Flow,a new approach to Nylon 6.6 circularity that e...Migdal Haemek,Israel,April 2,2024.NILIT,the global market leader,and a producer of high quality Nylon 6.6 for apparel and owner of the SENSIL?brand,introduces SENSIL?Flow,a new approach to Nylon 6.6 circularity that enables yarn,fabric,and,ultimately,apparel recycling to eliminate waste and further reduce apparel’s environmental impact.SENSIL?Flow is more than just a sustainable performance product.It is an innovative approach that engages the entire supply chain to truly attain circularity through product design and partnership.展开更多
Nylon 10T and nylon 10T/1010 samples were synthesized by direct melt polymerization.The isothermal crystallization kinetics of nylon 10T and nylon 10T/1010 was investigated by means of differential scanning calorimetr...Nylon 10T and nylon 10T/1010 samples were synthesized by direct melt polymerization.The isothermal crystallization kinetics of nylon 10T and nylon 10T/1010 was investigated by means of differential scanning calorimetry(DSC).The crystallization kinetics under isothermal condition has been analyzed by the Avrami equation.It was found that the Avrami equation was well-suited to describe the isothermal crystallization kinetics,combined with the results of the Turnbull-Fisher equation.The values of Tm^0 and Kg were obtained by Hoffman-Weeks and Lauritzen-Hoffman equations,respectively.The activation energies for isothermal crystallization of nylon 10T and nylon 10T/1010 were determined using the Arrhenius equation and found to be-123.24 and-81.86 kJ·mol^(-1),respectively,which reveals that the crystallization ability of nylon 10T/1010was lower than that of nylon 10T during the isothermal crystallization process.The crystal morphology was observed by means of polarized optical microscopy(POM)and X-ray diffraction(XRD).It was found that the addition of sebacic acid comonomer did not change the crystal form of nylon 10T,but significantly increased the number and decreased the size of spherulites.展开更多
The kineties of non-isothermal crystallization of Nylon-1010 has been investigated by using differential scanning calorimetry(DSC), DSC curves were obtained under cooling rate(R): 2. 5, 5, 10, 20, 40K/min. Applying Ma...The kineties of non-isothermal crystallization of Nylon-1010 has been investigated by using differential scanning calorimetry(DSC), DSC curves were obtained under cooling rate(R): 2. 5, 5, 10, 20, 40K/min. Applying Mandelkern and Ziabicki theories, the values of the Z kinetic parameter and G the kinetic crystalllzab- ility have been determined. Expenents of Avrami obtained in this work decrease with increase of cooling rate and then level off. The experimental results show disagreements with the Ozawa equation.展开更多
Fujian Eversun Jinjiang Co.,Ltd.(hereinafter referred to as“Eversun Jinjiang”)and China International Fabrics Design Competition once again jointly set up the“Nylon Product Development&Application Prize”in 202...Fujian Eversun Jinjiang Co.,Ltd.(hereinafter referred to as“Eversun Jinjiang”)and China International Fabrics Design Competition once again jointly set up the“Nylon Product Development&Application Prize”in 2023.After three consecutive years of growth,the award has brought together high-quality nylon products and high-level fabric development enterprises,and accelerated the process of industrial chain coordination and high-quality development.At the 2023 China International Fabrics Design Competition award ceremony held on August 28,fabrics from six outstanding textile enterprises respectively won the Fashion Color Award for Nylon Fabric,Innovation Award for Nylon Fabric Development,and Market Application Award for Nylon Fabric.The six award-winning fabrics in color,style,feel,technology,function,product fancy application has reached a new level compared to previous years.展开更多
A series of La2O3/MC nylon nanocomposites were prepared via in situ polymerization. The effects of content of nano-La2O3 on the mechanical properties of nanocomposites were studied. Dispersion of nano-La2O3 in MC nylo...A series of La2O3/MC nylon nanocomposites were prepared via in situ polymerization. The effects of content of nano-La2O3 on the mechanical properties of nanocomposites were studied. Dispersion of nano-La2O3 in MC nylon matrix was observed with SEM. The crystal structure of nanocomposites was characterized by means of XRD. SEM analysis shows that La2O3 nanoparticles are uniformly dispersed in MC nylon matrix and little clustering exists when the content of nano- La2O3 is lower than 1%, however, when the content of nano-La2O3 is more than 1%, it begins to cluster. XRD analysis indicats that nano-La2O3 does not change the crystal structure of MC nylon. Mechanical properties tests show that the tensile strength, elongation at break, impact strength, flexural strength, and flexural modulus of nanocomposites first increase then decrease as the content of nano-La2O3 is increased. When the content of nano-La2O3 is 0.5%, the tensile strength and elongation at break of nanocomposites reach maximum, which are 17.9% and 52.1% higher respectively than those of MC nylon. When the content of nano-La2O3 is 1.0%, the impact strength, flexural strength and flexural modulus of nanocomposites reach maximum, which are 36.6 %, 12.7 % and 16.3 % higher respectively than those of MC nylon.展开更多
To improve tribological property of MC Nylon6, the glass fiber and fly ash reinforced monomer casting nylon compogites (GFFAPA) were prepared by anionic polymerization of e-caprolactam. The friction and wear behavio...To improve tribological property of MC Nylon6, the glass fiber and fly ash reinforced monomer casting nylon compogites (GFFAPA) were prepared by anionic polymerization of e-caprolactam. The friction and wear behaviors of composites under dry condition, water lubrication and oil lubrication were investigated through a ring-black wear tester. Worn surfaces were analyzed using a scanning electron microscope. The experimental results show that the tensile strength and hardness of nylon composites are obviously improved with reinforcement increasing. Compared to MC nylon, the lowest friction coefficient and wear rate of glass fiber reinforced nylon composites (GFPA) with GF30% respectively decrease by 33.1% and 65.3%, of fly ash reinforced nylon composites (FAPA) with FA20% decrease by 5.2% and 68.9% and of GFFAPA composites with GF30% and FA10% decrease by 57.8% and 89.9%. The main wear mechanisms of FAPA composites are adhesive and abrasive wear and of GFPA composites with high proportion are abrasive and fatigue wear. The wom surfaces of GFFAPA composites are much multiplex and the optional distributing glass fiber and fly ash have a synergetic effect on the wear resistance for GFFAPA composites. Compared with dry friction, the friction coefficient and wear rate under oil lubricated conditions decrease sharply while the latter reversely increase under water lubricated conditions. The wear mechanisms under water lubricated condition are principally chemical corrosion wear and abrasive wear and they become boundary friction under oil lubricated condition.展开更多
Polyamide 1010 (PA1010)/thermoplastie poly (ether urethane) elastomer (ether-based TPU) blends were prepared via melt extrusion. The crystallization kinetics and melting behavior of PA1010/ether-based TPU blends...Polyamide 1010 (PA1010)/thermoplastie poly (ether urethane) elastomer (ether-based TPU) blends were prepared via melt extrusion. The crystallization kinetics and melting behavior of PA1010/ether-based TPU blends were systematically investigated using differential scanning calorimetry. The crystallization kinetics results show that the addition of ether-based TPU hinders the crystallization of PA1010, and the hindrance effect increases with the increase of the concentration of ether-based TPU. Both pure PA1010 and PA1010/ether-based TPU blends exhibit double melting peaks in the process of nonisothermal crystallization. The double melting peaks change differently with the variation of cooling rate and blend composition. The cooling rate only influences the lower melting peak; however, the blend composition influences not only the lower melting peak but also the higher melting peak. The reason for the phenomenon must be the interaction between the two compositions.展开更多
The preparation process-dependent phase morphology of blends composed of nylon 6 and acrylonitrile-butadiene- styrene(ABS)over a composition range of 30-70 wt% using a styrene-maleic anhydride(SMA)copolymer as the com...The preparation process-dependent phase morphology of blends composed of nylon 6 and acrylonitrile-butadiene- styrene(ABS)over a composition range of 30-70 wt% using a styrene-maleic anhydride(SMA)copolymer as the compatibilizing agent with a constant content(5phr)was investigated.The results of the scanning electron microscope (SEM)observation revealed that compared with the binary blends of nylon 6 and ABS,the existence of SMA caused a composition shift of phase inversion to a higher weight fraction of ny...展开更多
Analysis of isothermal and nonisothermal crystallization kinetics of nylon 66 was carried out using differential scanning calorimetry (DSC). The commonly used Avrami equation and that modified by Jeziorny were used, r...Analysis of isothermal and nonisothermal crystallization kinetics of nylon 66 was carried out using differential scanning calorimetry (DSC). The commonly used Avrami equation and that modified by Jeziorny were used, respectively, to fit the primary stage of isothermal and nonisothermal crystallizations of nylon 66. In the isothermal crystallization process, mechanisms of spherulitic nucleation and growth were discussed. The lateral and folding surface free energies determined from the Lauritzen-Hoffman treatment are sigma = 9.77 erg/cm(2) and sigma (e) = 155.48 erg/cm(2), respectively; and the work of chain folding is q = 33.14 kJ/mol. The nonisothermal crystallization kinetics of nylon 66 was analyzed by using the Mo method combined with the Avrami and Ozawa equations. The average Avrami exponent (n) over bar was determined to be 3.45. The activation energies (DeltaE) were determined to be -485.45 kJ/mol and -331.27 kJ/mol, respectively, for the isothermal and nonisothermal crystallization processes by the Arrhenius and the Kissinger methods.展开更多
Nylon cord rubber has the advantages of small residual deformation and is easy to lift and lower the tubing string in low-permeability oil and gas reservoirs.However,it is associated with low-pressure resistance and p...Nylon cord rubber has the advantages of small residual deformation and is easy to lift and lower the tubing string in low-permeability oil and gas reservoirs.However,it is associated with low-pressure resistance and poor sealing performance.To enhance the performance of nylon cord rubber,a three-dimensional numerical model of the nylon cord rubber was established and its accuracy experimentally determined.The Plackett-Burman test,the Steepest climbing test and the Response surface method were used to acquire the polynomial response surface model connecting structural parameters with bearing and sealing pressure.Using genetic algorithms,optimal structural parameters of nylon cord rubber were determined depending on field operation.The reliability of the optimized results was verified by laboratory tests.It was shown that after optimization,the bearing capacity of the expandable packer increased by 25%while the sealing performance increased by 66%.In addition,the bearing pressure was 70 MPa while the sealing pressure was 50 MPa.These measurements effectively met the on-site requirements of high-pressure and fine fracturing in low-permeability oil and gas reservoirs.展开更多
The wide-angle X-ray diffraction (WAXD) patterns of isothermally crystallized Nylon 1212 show that γ-form crystals form below 90℃ and the α-form crystals can exist above 140℃. In the temperature range of 90-140...The wide-angle X-ray diffraction (WAXD) patterns of isothermally crystallized Nylon 1212 show that γ-form crystals form below 90℃ and the α-form crystals can exist above 140℃. In the temperature range of 90-140℃, the α-form and γ-form crystals coexist. Variable-temperature WAXD exhibits that the nylon 1212 γ-form does not show crystal transition on heating, while α-form isothermally crystallized at 160℃ exhibits Brill transition at a little higher than 180℃ on heating. The multiple melting behaviors of Nylon 1212 isothermally crystallized from melt come from a complex mechanism of different crystal structures, dual lamellar population and melting-recrystallization. In polarized optical microscope (POM) observations, Nylon 1212 isothermally crystallized at 175℃ shows the ringed banded spherulites. However, at temperatures below 160℃ the ringed banded image disappears, and cross-extinct spherulites are formed.展开更多
The crystalline phase transition of aliphatic nylon 10/10 has been investigated on the basis of the simultaneous measurement of wide-angle and small-angle X-ray scatterings, the infrared spectral measurement and the m...The crystalline phase transition of aliphatic nylon 10/10 has been investigated on the basis of the simultaneous measurement of wide-angle and small-angle X-ray scatterings, the infrared spectral measurement and the molecular dynamics calculation. An interpretation of infrared spectra taken for a series of nylon samples and the corresponding model compounds was successfully made, allowing us to assign the infrared bands of the planar-zigzag methylene segments reasonably. As a result the methylene segmental parts of molecular chains were found to experience an order-to-disorder transition in the Brill transition region, where the intermolecular hydrogen bonds are kept alive although the bond strength becomes weaker at higher temperature. The small-angle X-ray scattering data revealed a slight change in lamellar stacking mode in the transition region. The crystal structure has been found to change more remarkably in the temperature region immediately below the melting point, where the conformationally disordered chains experienced drastic rotational and translational motions without any constraints by hydrogen bonds, and the lamellar thickness increased largely along the chain axis. These experimental results were reasonably reproduced by the molecular dynamics calculation performed at the various temperatures.展开更多
alpha Form Nylon 11 films were found to exist a non-linear transformation at 70 degrees C during the heating process using in situ WAXD. The alpha Form disappeared but delta Form appeared when the temperature was high...alpha Form Nylon 11 films were found to exist a non-linear transformation at 70 degrees C during the heating process using in situ WAXD. The alpha Form disappeared but delta Form appeared when the temperature was higher 70 degrees C.展开更多
Magnesia(MgO) nanoparticles were produced from magnesite ore(MgCO3) using ball mill. The crystalline size, morphology and specific SSA were characterized by X-ray diffraction analysis, transmission electron microscopy...Magnesia(MgO) nanoparticles were produced from magnesite ore(MgCO3) using ball mill. The crystalline size, morphology and specific SSA were characterized by X-ray diffraction analysis, transmission electron microscopy and Brunauer-Emmett-Teller method, respectively. MgO nanoparticle-incorporated nylon6 solutions were electrospun to produce nanofiber mats. Surface morphology and internal structure of the prepared hybrid nanofiber mats were examined by scanning electron microscopy and high-resolution transmission electron microscopy, respectively. The fire retardancy and antibacterial activity(Staphylococcus aureus and Escherichia coli) of coated fabrics made from MgO/nylon 6 hybrid nanofiber are better than those from nylon6 nanofiber.展开更多
Ultraviolet(UV)radiation can cause degradation or aging of many polymers and shorten the working-life of their products.Thus,UV protective covers are required in various occasions.Textiles with the UV-shielding functi...Ultraviolet(UV)radiation can cause degradation or aging of many polymers and shorten the working-life of their products.Thus,UV protective covers are required in various occasions.Textiles with the UV-shielding function possess unique properties compared with those covers in board or film shapes.TiO_2 nanoparticles(NPs),which were reported to have superior UV blocking function,can be used to produce UV protective covers in combination with fabric.However,efficient and environmentally friendly immobilization of TiO_2 Nps onto the fabrics is challenging.Polydopamine(PDA),a biomimetic synthetic polymer,has attracted great attentions recently due to its superior affinity to various materials and facile application procedure.Hence,in this research,the surface of nylon fabrics was modified by PDA to immobilizeTiO_2 NPs.Themodificationconditionswere systematically optimized.The immobilization of the NPs was confirmed by Fourier transform infrared spectrometer(FTIR)and scanning electron microscope(SEM).The functionalized nylon fabrics were proved to exhibit improved UV protection properties even after washing.This work provides a new and versatile surface modification technique for textiles.展开更多
基金supported jointly by the National Science and Technology Support Program (2012BAC08B07)the Natural Science Foundation of China (Nos. 2009BAC54B01-1 and 40930741)the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-EW-313)
文摘A V-shaped nylon net fence installed in 1990 on top of the Mogao Grottoes is shown to be effectively resisting aeolian sand damage to the grottoes. The structure guides and causes deposition of sand from westerly wind (the primary hard wind), but to some extent hinders the inverse function of easterly wind carrying sand away from the grottoes toward Mount Mingsha. The gobi side by the fence experiences higher wind speed, so that on which are easily formed undercutting pits, and the deposited sands on it generally form double-peak structures due to abundant sand sources. If the earth surface characteristics in gobi areas by both sides of the fence are quite varied, the erosion and deposition features of the accumulating sand section are similar in different seasons; however, if the earth surface characteristics are similar, the features become irregular in different seasons. Sand depositions with long slope feet are formed along the south and north sides of V-shaped nylon net fence. Disrupted by strong westerly wind and northwesterly wind, sand accumulations by north of the fence are in form of single peaks. Although the operation duration of the V-shaped nylon net fence has exceeded its design life (10 years), our observations indicate that it is still effective in reducing wind-driven sand damages to the Mogao Grottoes, so it should not be withdrawn.
基金support by National Key Research and Development Program of China(Grant No.:2023YFA0913604)Program of National Natural Science Foundation of China(Grant No.:22178170,22378195)+2 种基金Six talent peaks project in Jiangsu Province(SWYY-045)Program of National Natural Science Foundation of China(Grant No.22208155)Jiangsu Province Natural Science Foundation for Young Scholars(Grant No.BK20210552).
文摘Considerable progress has been made in recent years to the development of sustainable polymers from bio-based feedstocks.In this study,100%bio-based nylons were prepared via an integrated chemical and biological process from lignocellulose.These novel nylons were obtained by the melt polymerization of 3-propyladipic acid derived from lignin and 1,5-pentenediamine/1,4-butanediamine derived from carbohydrate sugar.Central to the concept is a three-step noble metal free catalytic chemical funnelling sequence(Raney Ni mediated reductive catalytic fractionation-reductive funnelling-oxidative funnelling),which allowed for obtaining a single component 3-propyladipic acid from lignin with high efficiency.The structural and thermodynamic properties of the obtained nylons have been systematically investigated,and thus obtained transparent bio-based nylons exhibited higher Mw(>32,000)and excellent thermal stability(Td5%>265℃).Considering their moderate Tg and good melt strength,these transparent bio-based nylons could serve as promising functional additives or temperature-responsive materials.
文摘Migdal Haemek,Israel,April 2,2024.NILIT,the global market leader,and a producer of high quality Nylon 6.6 for apparel and owner of the SENSIL?brand,introduces SENSIL?Flow,a new approach to Nylon 6.6 circularity that enables yarn,fabric,and,ultimately,apparel recycling to eliminate waste and further reduce apparel’s environmental impact.SENSIL?Flow is more than just a sustainable performance product.It is an innovative approach that engages the entire supply chain to truly attain circularity through product design and partnership.
基金Supported by the National Science and Technology Support Program of China(No.2013BAE02B01)the Special Project on the Integration of Industry,Education and Research of Guangdong Province(No.2013B090500003)the Commissioner Workstation Project of Guangdong Province(No.2014A090906002)
文摘Nylon 10T and nylon 10T/1010 samples were synthesized by direct melt polymerization.The isothermal crystallization kinetics of nylon 10T and nylon 10T/1010 was investigated by means of differential scanning calorimetry(DSC).The crystallization kinetics under isothermal condition has been analyzed by the Avrami equation.It was found that the Avrami equation was well-suited to describe the isothermal crystallization kinetics,combined with the results of the Turnbull-Fisher equation.The values of Tm^0 and Kg were obtained by Hoffman-Weeks and Lauritzen-Hoffman equations,respectively.The activation energies for isothermal crystallization of nylon 10T and nylon 10T/1010 were determined using the Arrhenius equation and found to be-123.24 and-81.86 kJ·mol^(-1),respectively,which reveals that the crystallization ability of nylon 10T/1010was lower than that of nylon 10T during the isothermal crystallization process.The crystal morphology was observed by means of polarized optical microscopy(POM)and X-ray diffraction(XRD).It was found that the addition of sebacic acid comonomer did not change the crystal form of nylon 10T,but significantly increased the number and decreased the size of spherulites.
文摘The kineties of non-isothermal crystallization of Nylon-1010 has been investigated by using differential scanning calorimetry(DSC), DSC curves were obtained under cooling rate(R): 2. 5, 5, 10, 20, 40K/min. Applying Mandelkern and Ziabicki theories, the values of the Z kinetic parameter and G the kinetic crystalllzab- ility have been determined. Expenents of Avrami obtained in this work decrease with increase of cooling rate and then level off. The experimental results show disagreements with the Ozawa equation.
文摘Fujian Eversun Jinjiang Co.,Ltd.(hereinafter referred to as“Eversun Jinjiang”)and China International Fabrics Design Competition once again jointly set up the“Nylon Product Development&Application Prize”in 2023.After three consecutive years of growth,the award has brought together high-quality nylon products and high-level fabric development enterprises,and accelerated the process of industrial chain coordination and high-quality development.At the 2023 China International Fabrics Design Competition award ceremony held on August 28,fabrics from six outstanding textile enterprises respectively won the Fashion Color Award for Nylon Fabric,Innovation Award for Nylon Fabric Development,and Market Application Award for Nylon Fabric.The six award-winning fabrics in color,style,feel,technology,function,product fancy application has reached a new level compared to previous years.
文摘A series of La2O3/MC nylon nanocomposites were prepared via in situ polymerization. The effects of content of nano-La2O3 on the mechanical properties of nanocomposites were studied. Dispersion of nano-La2O3 in MC nylon matrix was observed with SEM. The crystal structure of nanocomposites was characterized by means of XRD. SEM analysis shows that La2O3 nanoparticles are uniformly dispersed in MC nylon matrix and little clustering exists when the content of nano- La2O3 is lower than 1%, however, when the content of nano-La2O3 is more than 1%, it begins to cluster. XRD analysis indicats that nano-La2O3 does not change the crystal structure of MC nylon. Mechanical properties tests show that the tensile strength, elongation at break, impact strength, flexural strength, and flexural modulus of nanocomposites first increase then decrease as the content of nano-La2O3 is increased. When the content of nano-La2O3 is 0.5%, the tensile strength and elongation at break of nanocomposites reach maximum, which are 17.9% and 52.1% higher respectively than those of MC nylon. When the content of nano-La2O3 is 1.0%, the impact strength, flexural strength and flexural modulus of nanocomposites reach maximum, which are 36.6 %, 12.7 % and 16.3 % higher respectively than those of MC nylon.
基金Funded by the National High-Tech Projects('863' Program) (No.2002AA2Z4141)
文摘To improve tribological property of MC Nylon6, the glass fiber and fly ash reinforced monomer casting nylon compogites (GFFAPA) were prepared by anionic polymerization of e-caprolactam. The friction and wear behaviors of composites under dry condition, water lubrication and oil lubrication were investigated through a ring-black wear tester. Worn surfaces were analyzed using a scanning electron microscope. The experimental results show that the tensile strength and hardness of nylon composites are obviously improved with reinforcement increasing. Compared to MC nylon, the lowest friction coefficient and wear rate of glass fiber reinforced nylon composites (GFPA) with GF30% respectively decrease by 33.1% and 65.3%, of fly ash reinforced nylon composites (FAPA) with FA20% decrease by 5.2% and 68.9% and of GFFAPA composites with GF30% and FA10% decrease by 57.8% and 89.9%. The main wear mechanisms of FAPA composites are adhesive and abrasive wear and of GFPA composites with high proportion are abrasive and fatigue wear. The wom surfaces of GFFAPA composites are much multiplex and the optional distributing glass fiber and fly ash have a synergetic effect on the wear resistance for GFFAPA composites. Compared with dry friction, the friction coefficient and wear rate under oil lubricated conditions decrease sharply while the latter reversely increase under water lubricated conditions. The wear mechanisms under water lubricated condition are principally chemical corrosion wear and abrasive wear and they become boundary friction under oil lubricated condition.
基金Supported by the Science and Technology Council of Jilin Province(No 20020337)
文摘Polyamide 1010 (PA1010)/thermoplastie poly (ether urethane) elastomer (ether-based TPU) blends were prepared via melt extrusion. The crystallization kinetics and melting behavior of PA1010/ether-based TPU blends were systematically investigated using differential scanning calorimetry. The crystallization kinetics results show that the addition of ether-based TPU hinders the crystallization of PA1010, and the hindrance effect increases with the increase of the concentration of ether-based TPU. Both pure PA1010 and PA1010/ether-based TPU blends exhibit double melting peaks in the process of nonisothermal crystallization. The double melting peaks change differently with the variation of cooling rate and blend composition. The cooling rate only influences the lower melting peak; however, the blend composition influences not only the lower melting peak but also the higher melting peak. The reason for the phenomenon must be the interaction between the two compositions.
基金This work was supported by the National Science Funds for GuiZhou Province Science Projects(No.GY-2005-3036)the Special Funds for Major State Basic Research Projects(No.2005CB623802).
文摘The preparation process-dependent phase morphology of blends composed of nylon 6 and acrylonitrile-butadiene- styrene(ABS)over a composition range of 30-70 wt% using a styrene-maleic anhydride(SMA)copolymer as the compatibilizing agent with a constant content(5phr)was investigated.The results of the scanning electron microscope (SEM)observation revealed that compared with the binary blends of nylon 6 and ABS,the existence of SMA caused a composition shift of phase inversion to a higher weight fraction of ny...
基金This research was funded by the National Natural Science Foundation of China and subsidized by the Special Funds for Major State Basic Research Projects (G1999064800).
文摘Analysis of isothermal and nonisothermal crystallization kinetics of nylon 66 was carried out using differential scanning calorimetry (DSC). The commonly used Avrami equation and that modified by Jeziorny were used, respectively, to fit the primary stage of isothermal and nonisothermal crystallizations of nylon 66. In the isothermal crystallization process, mechanisms of spherulitic nucleation and growth were discussed. The lateral and folding surface free energies determined from the Lauritzen-Hoffman treatment are sigma = 9.77 erg/cm(2) and sigma (e) = 155.48 erg/cm(2), respectively; and the work of chain folding is q = 33.14 kJ/mol. The nonisothermal crystallization kinetics of nylon 66 was analyzed by using the Mo method combined with the Avrami and Ozawa equations. The average Avrami exponent (n) over bar was determined to be 3.45. The activation energies (DeltaE) were determined to be -485.45 kJ/mol and -331.27 kJ/mol, respectively, for the isothermal and nonisothermal crystallization processes by the Arrhenius and the Kissinger methods.
基金National Science and Technology major projects(2016ZX05042-004)Graduate Innovation Project(YCX2019059)for the financial support。
文摘Nylon cord rubber has the advantages of small residual deformation and is easy to lift and lower the tubing string in low-permeability oil and gas reservoirs.However,it is associated with low-pressure resistance and poor sealing performance.To enhance the performance of nylon cord rubber,a three-dimensional numerical model of the nylon cord rubber was established and its accuracy experimentally determined.The Plackett-Burman test,the Steepest climbing test and the Response surface method were used to acquire the polynomial response surface model connecting structural parameters with bearing and sealing pressure.Using genetic algorithms,optimal structural parameters of nylon cord rubber were determined depending on field operation.The reliability of the optimized results was verified by laboratory tests.It was shown that after optimization,the bearing capacity of the expandable packer increased by 25%while the sealing performance increased by 66%.In addition,the bearing pressure was 70 MPa while the sealing pressure was 50 MPa.These measurements effectively met the on-site requirements of high-pressure and fine fracturing in low-permeability oil and gas reservoirs.
基金This work was financially supported by the National Natural Science Foundation of China (Nos. 270274049 and 220374051) Jilin Provincial Commission of Science and Technology (No. 20020629).
文摘The wide-angle X-ray diffraction (WAXD) patterns of isothermally crystallized Nylon 1212 show that γ-form crystals form below 90℃ and the α-form crystals can exist above 140℃. In the temperature range of 90-140℃, the α-form and γ-form crystals coexist. Variable-temperature WAXD exhibits that the nylon 1212 γ-form does not show crystal transition on heating, while α-form isothermally crystallized at 160℃ exhibits Brill transition at a little higher than 180℃ on heating. The multiple melting behaviors of Nylon 1212 isothermally crystallized from melt come from a complex mechanism of different crystal structures, dual lamellar population and melting-recrystallization. In polarized optical microscope (POM) observations, Nylon 1212 isothermally crystallized at 175℃ shows the ringed banded spherulites. However, at temperatures below 160℃ the ringed banded image disappears, and cross-extinct spherulites are formed.
基金This study was supported financially by the MEXT "Collaboration with Local Communities" Project (2005-2009).
文摘The crystalline phase transition of aliphatic nylon 10/10 has been investigated on the basis of the simultaneous measurement of wide-angle and small-angle X-ray scatterings, the infrared spectral measurement and the molecular dynamics calculation. An interpretation of infrared spectra taken for a series of nylon samples and the corresponding model compounds was successfully made, allowing us to assign the infrared bands of the planar-zigzag methylene segments reasonably. As a result the methylene segmental parts of molecular chains were found to experience an order-to-disorder transition in the Brill transition region, where the intermolecular hydrogen bonds are kept alive although the bond strength becomes weaker at higher temperature. The small-angle X-ray scattering data revealed a slight change in lamellar stacking mode in the transition region. The crystal structure has been found to change more remarkably in the temperature region immediately below the melting point, where the conformationally disordered chains experienced drastic rotational and translational motions without any constraints by hydrogen bonds, and the lamellar thickness increased largely along the chain axis. These experimental results were reasonably reproduced by the molecular dynamics calculation performed at the various temperatures.
文摘alpha Form Nylon 11 films were found to exist a non-linear transformation at 70 degrees C during the heating process using in situ WAXD. The alpha Form disappeared but delta Form appeared when the temperature was higher 70 degrees C.
基金the financial support provided by the Defence Research Development Organisation (DRDO),New Delhi,for this project (ERIPR/ER/0905103/M/01/1279)
文摘Magnesia(MgO) nanoparticles were produced from magnesite ore(MgCO3) using ball mill. The crystalline size, morphology and specific SSA were characterized by X-ray diffraction analysis, transmission electron microscopy and Brunauer-Emmett-Teller method, respectively. MgO nanoparticle-incorporated nylon6 solutions were electrospun to produce nanofiber mats. Surface morphology and internal structure of the prepared hybrid nanofiber mats were examined by scanning electron microscopy and high-resolution transmission electron microscopy, respectively. The fire retardancy and antibacterial activity(Staphylococcus aureus and Escherichia coli) of coated fabrics made from MgO/nylon 6 hybrid nanofiber are better than those from nylon6 nanofiber.
基金National Natural Science Foundation of China(No.51503031)Pujiang Project from Shanghai Science and Technology Committee,China(No.15PJ1400300)+1 种基金Scientific Research Foundation for the Returned Overseas Scholars from the Ministry of Education,China(No.15B10127)Fundamental Research Funds for the Central Universities,China(No.2232015D3-02)
文摘Ultraviolet(UV)radiation can cause degradation or aging of many polymers and shorten the working-life of their products.Thus,UV protective covers are required in various occasions.Textiles with the UV-shielding function possess unique properties compared with those covers in board or film shapes.TiO_2 nanoparticles(NPs),which were reported to have superior UV blocking function,can be used to produce UV protective covers in combination with fabric.However,efficient and environmentally friendly immobilization of TiO_2 Nps onto the fabrics is challenging.Polydopamine(PDA),a biomimetic synthetic polymer,has attracted great attentions recently due to its superior affinity to various materials and facile application procedure.Hence,in this research,the surface of nylon fabrics was modified by PDA to immobilizeTiO_2 NPs.Themodificationconditionswere systematically optimized.The immobilization of the NPs was confirmed by Fourier transform infrared spectrometer(FTIR)and scanning electron microscope(SEM).The functionalized nylon fabrics were proved to exhibit improved UV protection properties even after washing.This work provides a new and versatile surface modification technique for textiles.