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1.
Tao Jian Wei‐De Shyu Yue‐Tang Lin Kan‐Nan Chen Jen‐Taut Yeh 《Polymer Engineering and Science》2003,43(11):1765-1777
The concentrations and temperatures of ultrahigh‐molecular‐weight polyethylene (UHMWPE) gel solutions exhibited a significant influence on their rheological and spinning properties. The shear viscosities of UHMWPE solutions increased consistently with increasing concentrations at a constant temperature above 80°C. Tremendously high shear viscosities of UHMWPE gel solutions were found as the temperatures reached 120–140°C, at which their shear viscosity values approached the maximum. The spinnable solutions are those gel solutions with optimum shear viscosities and relatively good homogeneity in nature. Moreover, the gel solution concentrations and spinning temperatures exhibited a significant influence on the drawability and microstructure of the as‐spun fibers. At each spinning temperature, the achievable draw ratios obtained for as‐spun fibers prepared near the optimum concentration are significantly higher than those of as‐spun fibers prepared at other concentrations. The critical draw ratio of the as‐spun fiber prepared at the optimum concentration approached a maximum value, as the spinning temperature reached the optimum value of 150°C. Further investigations indicated that the best orientation of the precursors of shish‐kebab‐like entities, birefringence, crystallinity, thermal and tensile properties were always accompanied with the as‐spun fiber prepared at the optimum concentration and temperature. Similar to those found for the as‐spun fibers, the birefringence and tensile properties of the draw fibers prepared at the optimum condition were always higher than those of drawn fibers prepared at other conditions but stretched to the same draw ratio. Possible mechanisms accounting for these interesting phenomena are proposed. 相似文献
2.
Jen‐Taut Yeh Tsong‐Wei Wu Yu‐Ching Lai Qi‐Cheng Li Huo‐Peng Zhou Qin Zhou Chi‐Hui Tsou Yao‐Chi Shu Chi‐Yuan Huang Kuo‐Shien Huang 《Polymer Engineering and Science》2011,51(12):2552-2563
The influences of the dispersion level of carbon nanotubes (CNTs) and functionalized CNTs on the transmittance properties of ultrahigh‐molecular weight polyethylene (UHMWPE) gel solutions and on ultradrawing properties of their as‐prepared fibers are reported. The transmittance properties suggest that the dispersion level of functionalized CNTs in UHMWPE/functionalized CNTs gel solution is significantly better than plain CNTs in UHMWPE/CNTs gel solutions. The orientation factors, achievable draw ratios, tensile strength (σf), and modulus (E) values of UHMWPE/CNTs (FxCy) and UHMWPE/functionalized CNTs (FxCf‐y) as‐prepared fiber specimens reached a maximum value as their CNT and functionalized CNT contents approached optimum contents at 0.00015 and 0.0001 wt%, respectively. The σf and E values of both FxC0.0012 and FxCf‐0.001 series fiber specimens prepared at their optimum CNT and functionalized CNT contents reached another maximum as their UHMWPE approached optimum UHMWPE concentration of 1.7 wt%. Possible reasons accounting for these interesting properties are proposed. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers 相似文献
3.
Jen‐Taut Yeh Yu‐Ching Lai Hai Liu Yao‐Chi Shu Chi‐Yuan Huang Kuo‐Shien Huang Kan‐Nan Chen 《Polymer International》2011,60(1):59-68
The influence of formation temperature on the ultradrawing properties of ultrahigh‐molecular‐weight polyethylene/carbon nanotube (UHMWPE/CNT) fiber specimens is investigated. Gel solutions of UHMWPE/CNT with various CNT contents were gel‐spun at the optimum concentration and temperature but were cooled at varying formation temperatures in order to improve the ultradrawing and tensile properties of the UHMWPE/CNT composite fibers. The achievable draw ratio (Dra) values of UHMWPE/CNT as‐prepared fibers reach a maximum when they are prepared with the optimum CNT content and formation temperature. The Dra value of UHMWPE/CNT as‐prepared fibers produced using the optimum CNT content and formation temperature is about 33% higher than that of UHMWPE as‐prepared fibers produced using the optimum concentration and formation temperature. The percentage crystallinity (Wc) and melting temperature (Tm) of UHMWPE/CNT as‐prepared fiber specimens increase significantly as the formation temperature increases. In contrast, Wc increases but Tm decreases significantly as the CNT content increases. Dynamic mechanical analysis of UHMWPE and UHMWPE/CNT fiber specimens exhibits particularly high α‐transition and low β‐transition, wherein the peak temperatures of α‐transition and β‐transition increase dramatically as the formation temperature increases and/or CNT content decreases. In order to understand these interesting drawing, thermal and dynamic mechanical properties of the UHMWPE and UHMWPE/CNT as‐prepared fiber specimens, birefringence, morphological and tensile studies of as‐prepared and drawn fibers were carried out. Possible mechanisms accounting for these interesting properties are proposed. Copyright © 2010 Society of Chemical Industry 相似文献
4.
Jen‐Taut Yeh Tsong‐Wei Wu Yu‐Ching Lai Huo‐Peng Zhou Qin Zhou Qi‐Cheng Li Sheng Wen Fang‐Chang Tsai Chi‐Yuan Huang Kuo‐Shien Huang Kan‐Nan Chen 《Polymer Engineering and Science》2011,51(4):687-696
Systemic investigation of the influence of the plain and functionalized carbon nanotube (CNT) contents on the ultradrawing properties of ultrahigh molecular weight polyethylene/carbon nanotubes (UHMWPE/CNTs, FCy) and UHMWPE/functionalized CNTs (FCfx‐y) as‐prepared fibers are reported. In a way similar to those found for the orientation factor values, the achievable draw ratios (Dra) of the FCy and FCfx‐y as‐prepared fibers approached a maximum value as their CNT and/or functionalized CNT contents reached their corresponding optimum values. The maximum Dra values obtained for FCfx‐0.001 as‐prepared fiber specimens prepared at varying maleic anhydride grafted polyethylene (PE‐g‐MAH)/modified CNTs weight ratios were significantly higher that of the FC0.0015 as‐prepared fiber specimen prepared at the optimum plain CNT content. Tensile property analysis further suggested that excellent orientation and tensile properties of the drawn FCy and FCfx‐y fibers can be obtained by ultradrawing the fibers prepared at their optimum plain CNT and/or functionalized CNT contents. To understand the interesting orientation, ultradrawing and tensile properties of FCy and FCfx‐y fiber specimens, FTIR, specific surface area, and SEM morphology analysis of the plain and functionalized CNTs were performed in this study. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers 相似文献
5.
Jen‐Taut Yeh Chuen‐Kai Wang Qin Zhou Huo‐Peng Zhou Chih‐Chen Tsai Yu‐Ching Lai Chi‐Hui Tsou Kan‐Nan Chen Chi‐Yuan Huang Kuei‐Chi Lee 《Polymer Engineering and Science》2013,53(9):1910-1919
Dimensions of conical dies were found to have a significant influence on thermal, morphological, orientation, ultradrawing, and dynamic mechanical properties of the as‐prepared and/or drawn ultrahigh molecular weight polyethylene (UHMWPE) fiber specimens prepared in this study. Many demarcated “micro‐fibrils” were found paralleling to fiber direction of the as‐prepared UHMWPE fiber specimens. The percentage crystallinity, melting temperatures, orientation factor (fo) and achievable draw ratio (Dra) values of each as‐prepared UHMWPE fiber specimen prepared at a fixed length of outlet land reach a maximum value, as the entry angles of the conical die approach the optimum value at 75°. The maximum fo and Dra values obtained for each F2075‐y as‐prepared fiber series specimens prepared using the optimum entry angle reach another maximum value as their length of outlet land approach the optimum value of 6.5 mm. The ultimate tensile strengths and moduli of the drawn UHMWPE fibers prepared at the optimum entry angle and length of outlet land are significantly higher than those of fibers prepared at other conditions but stretched to the same draw ratio. Possible reasons accounting for the above interesting properties were discussed in this study. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers 相似文献
6.
Wei Wei Xin‐Ling Wang Zhi‐Wei Liu Dong‐Rui Wu Liang Qiu Fang‐Chang Tsai Yu‐Ching Lai Ping Zhu Jen‐Taut Yeh 《Polymer Engineering and Science》2011,51(4):755-763
The drawing and ultimate tensile properties of the modified PA 6 (MPA) fiber specimens prepared at varying drawing temperature were systematically investigated, wherein the MPA resins were prepared by reactive extrusion of PA 6 with the compatibilizer precursor (CP). At any fixed drawing temperature, the achievable draw ratio (Dra) values of MPA as‐spun fiber specimens increase initially with increasing CP contents, and then approach a maximum value, as their CP contents are close to the 5 wt% optimum value. The maximum Dra values obtained for MPA as‐spun fiber specimens prepared at the optimum CP content reach another maximum as their drawing temperatures approach the optimum drawing temperature at 120°C. The tensile and birefringence values of PA 6 and MPA fiber specimens improve consistently as their draw ratios increase. Similar to those found for their achievable drawing properties, the ultimate tensile and birefringence values of MPA fiber specimens approach a maximum value, as their CP contents and drawing temperatures approach the 5 wt% and 120°C optimum values, respectively. Investigations including Fourier transform infrared, melt shear viscosity, gel content, thermal and wide angle X‐ray diffraction experiments were performed on the MPA resin and/or fiber specimens to clarify the optimum CP content and possible deformation mechanisms accounting for the interesting drawing, birefringence, and ultimate tensile properties found for the MPA fiber specimens prepared in this study. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers 相似文献
7.
Jen‐Taut Yeh Chuen‐Kai Wang Ping Hu Yu‐Ching Lai Lu‐Kai Huang Fang‐Chang Tsai 《Polymer International》2012,61(6):982-989
An investigation of the influence of the contents of original and modified attapulgite (ATP) on the ultradrawing properties of ultrahigh‐molecular‐weight polyethylene (UHMWPE)/ATP (FAx) and UHMWPE/modified ATP (FAmx) as‐prepared fibers is reported. Similar to what is found for the orientation factor values, the achievable draw ratios (Dra) of the FAx and FAmx as‐prepared fibers approach a maximum value as the original ATP and/or modified ATP contents reach their corresponding optimum values. The maximum Dra value obtained for FAmx as‐prepared fiber specimens is significantly higher than that for FAx as‐prepared fiber specimens prepared at the optimum original ATP content. Similar to what is found for the orientation factors and achievable drawing properties, the tensile strength (σf) and initial modulus (E) of both drawn F2Ax and F2Amx fiber series specimens with a fixed draw ratio reach maximum values as the original and/or modified ATP contents approach the optimum values, respectively. The σf and E values of the F2Amx fiber specimens are always significantly higher than those of the corresponding F2Ax fiber specimens prepared at the same draw ratios and ATP contents but without being modified. To understand the interesting ultradrawing, orientation and tensile properties of FAx and FAmx fiber specimens, Fourier transform infrared spectral, specific surface area, transmission electron microscopic and elemental analyses of the original and modified ATPs were performed. Copyright © 2012 Society of Chemical Industry 相似文献
8.
Ting Lei Kuo‐Shien Huang Mu‐Chen Kuo James Runt Jen‐Taut Yeh 《Polymer Engineering and Science》2019,59(7):1462-1471
This is the first investigation to report the processing and properties of ultrahigh molecular weight polyethylene (UHMWPE)/functionalized activated nanocarbon (FANC) gel solutions with the aid of supercritical carbon dioxide (scCO2). The ultradrawing and ultimate tensile properties of scCO2UHMWPE and scCO2UHMWPE/FANC fibers were found to improve considerably compared to those of UHMWPE and UHMWPE/FANC fibers prepared in the conventional way. The maximum achievable draw ratio obtained for the optimal scCO2UHMWPE/FANC fibers drawn at 95°C reached 445. The highest tensile tenacity (σf) of the fully drawn scCO2UHMWPE/FANC fiber reached an extraordinary high value of 104 g/d, which is about 3.2 and 1.1 times of that of the optimal UHMWPE and UHMWPE/FANC fully drawn fibers, respectively. The σf obtained for the optimally fully drawn scCO2UHMWPE/FANC fiber is about 25 times of those of steel fibers and is the highest tensile tenacity ever reported for single‐stage drawn polymeric fibers. Considerably lower dynamic transition temperatures and evaluated thinner crystal lamellae nucleated off of extended chains or FANC nucleants were found for as‐prepared scCO2UHMWPE and scCO2UHMWPE/FANC fibers compared with UHMWPE and UHMWPE/FANC fibers, respectively. Specific surface area, morphological, and Fourier transform infrared analyses of the activated nanocarbon (ANC), acid‐treated activated nanocarbon (ATANC) and FANC nanofillers and investigation of thermal, morphological, and orientation factor properties of the as‐prepared and drawn UHMWPE, UHMWPE/FANC, scCO2UHMWPE, and scCO2UHMWPE/FANC fibers were performed to understand the remarkable ultradrawing, dynamic transition, and ultimate tensile properties obtained for scCO2UHMWPE and scCO2UHMWPE/FANC fibers. POLYM. ENG. SCI., 59:1462–1471 2019. © 2019 Society of Plastics Engineers 相似文献
9.
Jen‐Taut Yeh Chuen‐Kai Wang Alice Yeh Lu‐Kai Huang Wen‐Hung Wang Kuo‐Huang Hsieh Chi‐Yuan Huang Kan‐Nan Chen 《Polymer International》2013,62(4):591-600
Ultrahigh molecular weight polyethylene (UHMWPE)/nanosilica (F2Sy) and UHMWPE/modified nanosilica (F2Smx‐y) as‐prepared fibers were prepared by spinning of F2Sy and F2Smx‐y gel solutions, respectively. Modified nanosilica particles were prepared by grafting maleic anhydride grafted polyethylenes onto nanosilica particles. The achievable draw ratios (Dra) of F2Sy and F2Smx‐y as‐prepared fibers approached a maximal value as the original and modified nanosilica contents reached corresponding optimum values; the maximal Dra value obtained for F2Smx‐y as‐prepared fiber specimens was significantly higher than that of the F2Sy as‐prepared fiber specimens prepared at the optimum nanosilica content. The melting temperature and evaluated lamellar thickness values of F2Sy and F2Smx‐y as‐prepared fiber series specimens decrease, but crystallinity values increase significantly, as their original and modified nanosilica contents respectively increase. Similar to the achievable drawing properties of the as‐prepared fibers, the orientation factor, tensile strength (σf) and initial modulus (E) values of both drawn F2Sy and F2Smx‐y fiber series specimens with a fixed draw ratio reach a maximal value as the original and/or modified nanosilica contents approach the optimum values; the σf and E values of the drawn F2Smx‐y fiber specimens are significantly higher than those of the corresponding drawn F2Sy fiber specimens prepared at the same draw ratios and nanosilica contents but without being modified. To understand the interesting ultradrawing, thermal, orientation and tensile properties of F2Sy and F2Smx‐y fiber specimens, Fourier transform infrared, specific surface area and transmission electron microscopy analyses of the original and modified nanosilica were performed in this study. © 2012 Society of Chemical Industry 相似文献
10.
Enhancement on ultimate tensile properties of ultrahigh molecular weight polyethylene composite fibers filled with activated nanocarbon particles with varying specific surface areas
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Wang‐Xi Fan Yi Ding Zhong‐Dan Tu Kuo‐Shien Huang Chao‐Ming Huang Jen‐Taut Yeh 《Polymer Engineering and Science》2018,58(6):980-990
This investigation aims to improve the ultradrawing and ultimate tensile properties of ultrahigh molecular weight polyethylene (UHMWPE) fibers by incorporating small amounts of functionalized activated nanocarbon particles with a wide range of specific surface areas (ca. 100–1,400 m2/g) during gel spinning processes of UHMWPE fibers. The ultradrawing, ultimate tensile, orientation properties, and “microfibril” characteristics of UHMWPE/functionalized activated nanocarbon fibers was discovered to improve considerably with the increase in specific surface areas of functionalized activated nanocarbon. An extraordinary high ultimate tensile strength at 95.8 g/d was obtained for the best prepared UHMWPE/functionalized activated nanocarbon drawn fiber. This value is the highest value ever reported for one‐stage drawn UHMWPE fibers and is about 2.9 times that of the UHMWPE drawn fiber prepared in this study. In addition to thermal, ultimate tensile, and orientation factor properties of as‐prepared and/or drawn UHMWPE/functionalized activated nanocarbon fibers, specific surface area, Fourier transform infrared, and morphological analyses of original and functionalized activated nanocarbons were performed to comprehend the considerably improved ultradrawing, ultimate tensile properties, and microfibril characteristics of the UHMWPE/functionalized activated nanocarbon fibers. POLYM. ENG. SCI., 58:980–990, 2018. © 2017 Society of Plastics Engineers 相似文献
11.
This study examined the effect of the ultradrawing behavior of gel film specimens of ultrahigh‐molecular‐weight polyethylene (UHMWPE) and UHMWPE/low‐molecular‐weight polyethylene (LMWPE) blends on their physical properties. The concentration of a gel film approximated its critical concentration at a fixed drawing temperature; its achievable draw ratio was higher than that of other blend specimens with various concentrations. Noticeably, when about 5 wt % LMWPE was added to a UHMWPE/LMWPE gel film specimen, the achievable draw ratio of the gel film increased, and this contributed to an apparent promoting effect on its anticreeping properties and thermal stability. Therefore, when ULB?0.9 was drawn to a draw ratio of 300, the anticreeping behavior was improved to less than 0.026%/day. Moreover, with respect to the thermal stability, when the same specimen was drawn to a draw ratio of 300, the retention capability of its storage modulus could resist a high temperature of 150°C, which was obviously much higher than the temperature of an undrawn gel film specimen (70°C). To study these interesting behaviors further, this study systematically investigated the gel solution viscosities, anticreeping properties, dynamic mechanical properties, thermal properties, molecular orientations, and mechanical properties of undrawn and drawn UHMWPE/LMWPE gel film specimens. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 相似文献
12.
The ultradrawing behavior of gel films of plain ultrahigh molecular weight polyethylene (UHMWPE) and UHMWPE/low molecular weight polyethylene (LMWPE) blends was investigated using one- and two-stage drawing processes. The drawability of these gel films were found to depend significantly on the temperatures used in the one- and two-stage drawing processes. The critical draw ratio (λc) of each gel film prepared near its critical concentration was found to approach a maximum value, when the gel film was drawn at an “optimum” temperature ranging from 95 to 105°C. At each drawing temperature, the one-stage drawn gel films exhibited an abrupt change in their birefringence and thermal properties as their draw ratios reached about 40. In contrast, the critical draw ratios of the two-stage drawn gel films can be further improved to be higher than those of the corresponding single-stage drawn gel films, in which the two-stage drawn gel films were drawn at another “optimum” temperature in the second drawing stage after they had been drawn at 95°C to a draw ratio of 40 in the first drawing stage. These interesting phenomena were investigated in terms of the reduced viscosities of the solutions, thermal analysis, birefringence, and tensile properties of the drawn and undrawn gel films. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 149–159, 1998 相似文献
13.
Nanocomposite fibers of ultra high molecular weight polyethylene (UHMWPE) and organic montmorillonite (OMMT) were successfully prepared by a melt‐spinning process. The evolution of the microstructures of the nanocomposite fibers in the drawing process was preliminarily studied by X‐ray diffraction (XRD), differential scanning calorimetry, and small‐angle X‐ray scatters. With the increase of draw ratio values, the crystallinity of the nanocomposite fibers increased, the grain size decreased, and the folded chain crystals gradually transformed into extended chain crystals. The results suggested the evolution of the nanocomposite fibers was similar with that of the fibers made by gel‐spun drawing process. The addition of OMMT in UHMWPE improved the fluidity of the composites yet without affecting the crystal structure of UHMWPE in the drawing process. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3930–3936, 2013 相似文献
14.
For the purpose of the development of ultrahigh molecular weight polyethylene (UHMWPE) fibers with improved tensile properties, the stearic acid (SA) was added to the gel spinning of UHMWPE and acted as a lubricant film. SA addition was intended to be 0.2, 0.4, 0.6, 0.8, and 1.0 wt% of UHMWPE for forming the SA modified UHMWPE fibers. The tensile properties, thermal properties, crystallization properties, and orientation properties of the prepared UHMWPE fibers were systematically investigated. Results show that there is a more significant tensile property for UHMWPE fibers as SA addition is 0.6 wt%. Their tensile strength and tensile modulus reach 32.86 and 1580.89 cN/dtex, which are raised to an extent of 12.0% and 7.7%, respectively, compared with UHMWPE fibers alone. Moreover, the thermal properties, crystallization properties, and orientation properties of the prepared UHMWPE fibers are enhanced observably when the SA addition is 0.6 wt%. 相似文献
15.
A systematic study of the influence of the drawing temperature and rate on the ultradrawing properties of film samples prepared from gel solutions of ultrahigh molecular weight polyethylene and low molecular weight polyethylene blends is reported. At a fixed drawing rate, the achievable draw ratios reached a maximum value when each film specimen was drawn at a temperature near its optimum temperature (Top). It is interesting to note that the Top values of each film sample increased consistently with the drawing rate. The achievable draw ratio of each film sample drawn at a constant rate and a temperature near Top is referred to as the Draop, which reached another maximum value as the drawing rates approached an optimum value. Dynamic mechanical analysis of the film sample exhibited an extraordinary high transition peaked at temperature near 95°C, which is again very close to the Top value found for the film sample drawn at a relatively low rate. On the other hand, the birefringence values and tensile strengths of the film specimen were found to improve significantly with the draw ratios, although the improvement of these properties reduced significantly at high draw ratios. Moreover, both the drawing temperature and rate showed beneficial influence on the birefringence, and tensile strengths of the drawn film specimens. Possible mechanisms accounting for these interesting deformation properties are suggested. 相似文献
16.
Qing‐Xiu Jia Zu‐Jiang Xiong Chao‐Ming Shi Li‐Qun Zhang Xiao‐Ning Wang 《应用聚合物科学杂志》2012,124(6):5165-5171
Polyamide 6 (PA6) fibers were prepared by CaCl2 complexation and the gel spinning technique. PA6 was partially complexed with CaCl2 for the purpose of suppressing interchain amide group hydrogen bonding. The fibers were characterized with scanning electron microscopy, X‐ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy. In the gel spinning process, a mixed tetrachloroethane and chloroform solution was chosen as the coagulation bath after a comparison of different types of solutions. From our investigation of the morphology, structure, and mechanical properties of gel‐spun and hot‐drawn fibers, it was indicated that the modulus and tensile strength increased with increasing draw ratio, the orientation of the fibers was improved, and the cross section of the PA6 gel fibers became more smooth and tight. The results from the XRD, DSC, and FTIR tests indicated that calcium metal cations complexed with the carbonyl oxygen atoms of PA6. The maximum modulus and tensile strength values obtained in this study were 28.8 GPa and 413 MPa, respectively, at a draw ratio of 8. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
17.
T. Mikolajczyk G. Szparaga M. Bogun A. Fraczek‐Szczypta S. Blazewicz 《应用聚合物科学杂志》2010,115(6):3628-3635
Carbon nanotubes (CNTs) were used to modify polyacrylonitrile (PAN) polymer. The PAN/CNT composite fibers were spun from dimethylformamide solutions containing different types of CNTs. The effect of nanotube addition to the fiber precursor on the resulting mechanical properties is discussed. In this study, we examined the relationship of the rheological properties of PAN spinning solutions containing various types of CNTs and the tensile strength of the resulting PAN fibers. The presence of CNTs in the PAN spinning solution enhanced its deformability during the drawing stage. This effect resulted in a higher tensile strength in the fibers containing nanotubes, as compared to the pure fibers. The use of a three‐stage drawing process resulted in a significant increase in the tensile strength of PAN fibers modified with multiwalled nanotubes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
18.
利用冻胶纺丝的方法制备了超高相对分子质量聚乙烯/碳纳米管(UHMWPE/CNTs)复合纤维,以高锰酸钾和硫酸为氧化剂对CNTs进行纯化处理,用DNZ-201钛酸酯对纯化处理后的CNTs进行功能化处理。采用TEM、SEM和FTIR对CNTs的形态、基团变化和CNTs在UHMWPE中的分散情况进行测试。结果表明,该氧化剂对CNTs的纯化有良好的效果,可以除去大部分附在CNTs上的杂质,产生了有利于功能化的有机基团;SEM和TEM测试结果表明,功能化处理后CNTs可以较为均匀地分散在UHMWPE基体中,没有出现明显的CNTs的团聚现象,而且使UHMWPE大分子排列趋于规整。 相似文献
19.
Micron‐sized fibers of UHMWPE reinforced with CNT were fabricated by the electrospinning process. Conditions for a metastable mutual solution of UHMWPE and CNTs were found at elevated temperature. These solutions were used for electrospining using a device having controlled temperature and gaseous environment around the electrospun liquid jet. The fabricated micron‐sized fibers exhibited the reinforcing CNTs as self‐organized nano‐ropes embedded within them. A post‐spinning drawing process enhanced the mechanical properties of the composite fibers to the level of 6.6 GPa strength and elongation at break of 6%. The CNT nano‐ropes form spontaneously in the liquid jet during electrospinning, and provide the reinforcement framework which is amenable for post‐drawing of the fibers for subsequent utilization as composite nanofibers. The experimental results exhibit the highest strength value reported to date for electrospun fibers.
20.
Polyvinyl alcohol (PVA)/gelatin composite fibers containing carbon nanotubes (CNTs) had been prepared by wet‐spinning method. A remarkable increase of tensile strength of the PVA/gelatin fibers was achieved by adding small amount of CNT. The mechanism of reinforcement has been studied using a combination of differential scanning calorimetry (DSC), 2D wide‐angle X‐ray diffraction (2D‐WAXD) and scanning electron microscopy (SEM). SEM showed a decreased gelatin domain size by adding CNTs, suggesting a possible compatibilization effect between PVA and gelatin. On the other hand, an increased crystallinity and degree of orientation of PVA/gelatin fibers has been observed by adding CNTs. Thus, the increased compatibilization, crystallinity and degree of orientation in PVA/gelatin/CNTs composite fibers should be the reasons for the observed increase of mechanical properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献