聚苯胺尼龙导电织物的制备及其传感性能

采用低温原位聚合法在尼龙织物表面形成一层聚苯胺导电材料，并用场发射扫描电子显微镜和显微拉曼成像光谱仪对其形貌及化学组成进行表征，用万用表和电化学工作站测试其导电性能。结果表明，聚苯胺聚合在尼龙织物的表面，赋予织物较好的导电性，织物电导率为31.62 S/m。聚苯胺尼龙织物的电阻随应变的增大而增大，当应变回复到初始状态时，织物电阻逐渐恢复并接近初始值，在3500次拉伸-回复循环后仍有96.2%的高循环稳定性。作为导电织物，聚苯胺尼龙织物具有良好的传感性能，在0~15%应变范围内可以准确监测人体的关节运动。同时，聚苯胺尼龙导电织物也具有热电性能，织物的塞贝克系数为8.406μV/K，有望作为温差传感器。     

Polyimide and nylon 6 blend film: Preparation,characterization and thermal behavior

A polyimide blend system has been prepared from a base polyimide of BTDAODA by adding ε‐caprolactam at the poly(amic acid) stage where ε‐caprolactam undergoes polymerization to form nylon 6 during the thermal cyclodehydration of poly(amic acid). The blend has been characterized by elemental analysis. IR, ¹³C CPMAS NMR, XRD and simple chemical methods. The thermal analysis study (TGA and DTA) shows that the stability of the blend systems is more in the lower temperature region (up to 300°C) in comparison to the control polyimide system. The isothermal study at 400°C in inert atmosphere shows that the blend system is equally stable but the isothermal study in air at 400°C shows that the thermooxidative stability of the blend films (except BB 4) is higher. Also, isothermal study in air at 500°C shows more than 90% weight loss for all the films within 3 h, but in an inert atmosphere, the blend films show lower weight loss compared to the control film. Although the XRD pattern of all the blend and control films shows an amorphous character, the films developed some crystallinity when treated with boiling NMP where the blend films developed higher crystallinity.     

The tracer diffusion of dye anions in nylon 6 film

The tracer diffusion coefficients of three S-35-labeled dyes in nylon 6 film have been determined. The diffusion coefficients show marked concentration dependence, but this takes a form different from that shown by chloride ions in a related study. It is not possible to explain the data on the basis of electrostatic factors as in earlier work in which diffusion was accompanied by a free-energy change. A diffusional interaction between dye molecules is postulated which takes the form of a free-volume saturation effect leading to an upper limiting diffusion coefficient at adsorption levels which depend upon the polymer order and the characteristics of the diffusing ion.     

Preparation of porous nylon 6 fiber via electrospinning

Porous nylon‐6 fibers were obtained by electrospinning of ultra‐high molecular polyamide 6 (UHMW‐PA6). First, UHMW‐PA6/calcium formate composite nanofibers were prepared as precursors by electrospinning UHMW‐PA6 solutions containing different contents of calcium formate particles. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to examine the surface morphology and inner structure of composite nanofibers. It was found that calcium formate particles were distributed both inside and on the surface of nanofibers. Fourier transform infrared (FTIR), differential scanning calorimetry, and thermal gravimetric analysis (TGA) were used to study the structure and properties of these nanofibers. Then, porous UHMW‐PA6 nanofibers were obtained by soaking the electrospun web in water for 24 h, to remove calcium formate particles. The removal of calcium formate particles was confirmed using FTIR and TGA tests. SEM and TEM observations revealed the formation of porous structure in these nanofibers. In addition, CaCl₂ was used instead of calcium formate to prepare the UHMW‐PA6 nanoporous fiber. POLYM. ENG. SCI., 55:1133–1141, 2015. © 2014 Society of Plastics Engineers     

Thermally conductive carbon filled nylon 6,6

Increasing the thermal conductivity of typically insulating polymers, such as nylon 6,6, opens new markets. A thermally conductive resin can be used for heat sink applications. This research focused on performing compounding runs followed by injection molding and through-plane thermal conductivity testing of carbon filled nylon 6,6 based resins. The three carbon fillers investigated included an electrically conductive carbon black, synthetic graphite particles, and a surface treated polyacrylonitrile (PAN) based carbon fiber. Conductive resins were produced and tested that contained varying amounts of these single carbon fillers. In addition, combinations of fillers were investigated by conducting a full 2³ factorial design and a complete replicate. The objective of this paper was to determine the effects and interactions of each filler on the thermal conductivity of the resins. Synthetic graphite particles caused the largest increase in composite thermal conductivity. In addition, all the single fillers and combinations of fillers caused a statistically significant (at the 95% confidence level) increase in composite thermal conductivity. Polym. Compos. 25:186–193, 2004. © 2004 Society of Plastics Engineers.     

Electrically and thermally conductive nylon 6,6

Increasing the thermal and electrical conductivity of typically insulating polymers, such as nylon 6,6, opens new markets. A thermally conductive resin can be used for heat sink applications. An electrically conductive resin can be used in static dissipative and Electromagnetic Interference/Radio Frequency Interference shielding applications. This research focused on adding various carbon based conductive fillers and a chopped glass fiber to nylon 6,6. These materials were extruded and injection molded into test specimens. Tensile tests as well as in-plane electrical resistivity, in-plane thermal conductivity, and through-plane thermal conductivity tests were conducted. One successful formulation consisted of 10% 3.2 mm chopped E-glass fiber/15% Thermocarb (high quality synthetic powdered graphite)/5% carbon black/70% nylon 6,6 (all % in wt%). For this formulation, the in-plane electrical resistivity was reduced from 10¹⁵ ohm-cm (neat nylon 6,6) to 15 ohm-cm. The through-plane thermal conductivity increased from 0.25 W/mK (neat nylon 6,6) to 0.7 W/mK. The tensile elongation at failure was 1.4%.     

尼龙6/纳米蒙脱土复合材料制备及性能研究

利用活化处理的纳米蒙脱土(OMMT),通过原位插层聚合原理,控制聚合温度、压力、时间等,在聚合管实现连续化稳定制备剥离型尼龙6(PA6)/纳米OMMT复合材料;采用熔融纺丝法制得PA6/纳米OMMT复合纤维;利用X射线衍射、透射电镜(TEM)等方法分析复合材料的结构与性能。结果表明:聚合时控制水与己内酰胺质量比为3%～5%,前聚压力不超过0.4 MPa,后聚压力小于-0.040 MPa,聚合温度240～280℃,聚合时间26～30 h,可制得相对分子质量为18 000～18 600,单体质量分数小于1.6%,含水率小于450μg/g的PA6/纳米OMMT切片;TEM分析表明,纳米OMMT在PA6基体均匀分散;复合材料的力学性能有较大幅度的提高,断裂强度达102.15 MPa,比纯PA6提高了12%;PA6/纳米OMMT复合纤维性能优异,适合轮胎骨架材料的制备要求。     

凯芙拉纤维/尼龙6热塑性复合材料的研制

研究了凯芙拉纤维与尼龙 6单体通过阴离子原位聚合制备热塑性复合材料的方法。以氢氧化钠为引发剂 ,甲苯二异氰酸酯 (TDI)为活化剂 ,确定体系的聚合温度为 160℃ ,引发剂、活化剂用量为6.42 m ol/L ,聚合时间 60 min,在此条件下聚合速度较快 ,单体转化率 1h后达 95 %以上。研究发现 ,凯芙拉纤维经酰化处理后 ,基本上不会对己内酰胺阴离子聚合体系产生阻聚作用     

Properties of bioriented nylon 6 films related to film production technology

Four production steps, extrusion, blowing, stabilization, and finishing, are involved in the manufacture of biorented nylon 6 films. The films obtained after each step were studied by wide‐angle diffraction X‐rays, IR analysis, and density measurements. Orientation in the amorphous phase was evaluated by thermal retraction. Free volume was investigated by positron annihilation spectroscopy. Mechanical properties were tested by tensile tests, and permeability was tested with isopiestic permeameters. Quenching, after extrusion, generated an unstable γ crystalline phase and an amorphous phase. Blowing transformed the unstable γ phase into the thermodynamically stable α phase and increased the chain orientation; stabilization increased α phase crystals, favored hydrogen bond formation and, therefore, the mechanical properties, leaving unchanged the chain orientation; the final treatment increased the mechanical properties. The film permeabilities to O₂, N₂, and CO₂ were practically unchanged after each production step; this result may be explained by considering that the nanoholes, present in the films and responsible for the diffusion inside the polymer, maintained practically constant their radius, whereas their number concentration decreased slowly after thermomechanical treatments. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 559–571, 2002     

尼龙用导电涂料配方设计

为了提高尼龙底材用导电涂料的附着力和贮存稳定性,设计了尼龙用导电涂料配方.通过分析树脂、导电填料、溶剂、助剂以及颜基比对导电涂料性能的影响,获得了最佳配方如下(以质量分数表示):羟基丙烯酸树脂20%,封闭异氰酸酯6%,改性聚酯2%,银包铜粉(wAg=50%)40%、复合溶剂30%以及助剂2%.     

Preparation and characterization of star-shaped nylon 6 with high flowability

Three kinds of star-shaped nylon 6 samples with different branched-chain length were prepared by the hydrolytic polymerization of ε-caprolactam using trimesinic acid as trifunctional reactant. The structure of prepared star-shaped nylons was characterized by infrared spectroscopy and ¹H-NMR. Compared with linear-chain nylon 6, star-shaped nylons with the equivalent molecular weight present higher melt flow indices and lower relative viscosities due to decreased molecular dimensions and reduced hydrogen bond interactions between neighboring molecules. The molecular weights of the products were determined by end-group titration and ¹H-NMR, and the molecular weight distributions (MWDs) were evaluated by gel permeation chromatography. The results show that the molecular weight decreased and the MWD narrowed as the concentration of trimesinic acid increased. Wide-angle X-ray diffraction patterns of star-shaped and linear-chain nylons show that increasing the concentration of trimesinic acid leads to good symmetry and high crystallizability, but this also degrades crystal perfection as observed using a polarized optical microscope. The viscosity of nylon 6 can be significantly reduced while maintaining its mechanical performance through the use of star-branching and an appropriate concentration of trimesinic acid.     

Preparation and characterization of nylon 6/organoclay nanocomposite filament fibers

A series of nylon 6 (NY6)/organoclay nanocomposites were prepared via in situ polymerization of ε‐caprolactam in the presence of 1,2‐aminododecanoic acid‐intercalated montmorillonite (ADA‐MMT) organoclay (1–5 wt%) using 6‐aminocaproic acid as polymerization catalyst. The extent of organoclay dispersion in NY6 matrix was analyzed using WAXD and SEM measurements. DSC studies revealed marginal shift in melting and melt‐crystallization peaks toward lower temperature with increasing clay content. Melt viscosity studies for NY6/ADA‐MMT exhibited higher shear‐thinning behavior than neat NY6 probably due to the slip between NY6 matrix and exfoliated organoclay platelets during shear flow. The prepared nanocomposites were melt‐spun and studied for their property improvements against varying clay content, draw ratios, and annealing conditions. Birefringence and sonic velocity values increased initially at lower draw ratios (≤2.5) due to increased orientation of molecular chains along the drawing direction but saturated at higher draw ratio (3.0) for all the samples. At the same draw ratio; compared to neat NY6, NY6/organoclay fibers showed increased chain orientation along the drawing direction which can be attributed to the “tethering effect” of organoclay on NY6 matrix. The initial modulus and stress at break were sensitive to factors such as draw ratio, clay content, and annealing conditions. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Vibration welding of nylon 6 to nylon 66

Vibration welding of dissimilar nylons is a promising technique for assembling complex components made of different polymers. The effects of pressure and meltdown on the tensile strength of nylon 6 (PA 6) to nylon 66 (PA 66) vibration welds were determined in this study using an experimental design and three weld geometries. Weld strengths were generally improved by increasing meltdown and decreasing weld pressure. The weld strength was also shown to vary with the position of the lower melting material for T‐welds. Using differential scanning calorimentry and fracture surface analyses, it is concluded that for all geometries, higher weld strengths can be achieved when both materials are melted. Polym. Eng. Sci. 44:760–771, 2004. © 2004 Society of Plastics Engineers.     

尼龙6-聚乙烯合金/蒙脱土纳米复合材料的制备与物理机械性能

用熔融插层法制备了尼龙6-聚乙烯合金/蒙脱土纳米复合材料.X射线衍射表明,在有机蒙脱土质量分数为4%,6%时,蒙脱土被剥离成片层分散在基体中;进一步提高蒙脱土质量分数至10%,蒙脱土部分剥离,部分插层.物理机械性能测试结果表明,将有机蒙脱土加入尼龙6-聚乙烯合金中能显著提高复合材料的拉伸强度、弯曲强度、冲击强度.其中冲击强度最大可以提高100%以上.     

Preparation and properties of transparent and conducting nylon 6-based composite films

Highly transparent and conducting polypyrrole–(PPy–N) and polyaniline–nylon 6 (PAN) composite films could be easily obtained by immersing nylon 6 films containing pyrrole or aniline into an oxidant solution such as aqueous FeCl₃ solution or aqueous (NH₄)₂S₂O₈ solution containing HCl. The conductivity, transmittance, and mechanical properties of these composite films were affected by the preparative conditions. The maximum conductivity and transmittance of the PPy–N composite films were 10^?3 S/cm and about 75% at 550 nm, and in the case of the PA–N composite films, 10^?2 S/cm and 75%, respectively. The morphology of PPy–N and PA–N composite films depended on the polymerization conditions, which might be due to the difference in the polymerization speed of pyrrole or aniline in polymer matrices. These PPy–N and PA–N composite films exhibited good environmental stability and excellent mechanical properties. © 1994 John Wiley & Sons, Inc.     

Fabrication of MWNTs/nylon conductive composite nanofibers by electrospinning

MWNT/nylon 6, 6 composite nanofibers were fabricated using an electrospinning method, and the electrical properties were examined as a function of the filler concentration. Initially, the pristine, purified MWNTs were treated with a 3:1 mixture of concentrated H₂SO₄/HNO₃ to introduce carboxyl groups onto the MWNT surface. The carboxylated MWNTs were then treated with thionyl chloride and an ethylenediamine solution for amide functionalization. FT-IR spectroscopy was used to examine the functionalization of the MWNTs. Nylon 6, 6 is readily soluble in formic acid. Therefore, the amide functionalized MWNTs were dispersed in formic acid. The solution remained stable and uniform for more than 40 h. –NH₂ termination of the MWNTs improved the dispersion stability of the MWNTs in formic acid. The MWNTs-suspended in a solution of nylon 6, 6 in formic acid was electrospun to obtain the nanofibers. The electrical properties of the nanofibers were examined as a function of the filler concentration. The results showed that the I–V properties of the nanofiber sheet improved with increasing filler concentration.     

Preparation and characterization of polyaniline coated microspheres for potential application in anisotropic conductive film

Monodispersed polyaniline-coated (PANi) microspheres with a mean diameter of 5.174 μm and a 3.53% coefficient of variation were successfully prepared through an in-situ chemical oxidation polymerization of aniline on the surface of high-crosslinked polystyrene-divinylbenzene (PSDVB) particles with the mass ratio of 1: 0.12 between PSDVB particles and aniline. The microspheres were characterized by the scanning electron microscopy (SEM), FTIR and elemental analysis. A very thin layer of polyaniline, about 10.5% in weight, was found to evenly cover on the PSDVB, The microspheres were demonstrated to be thermal stable below 450 °C by thermogravimetric analysis (TGA) measurements and have a bulk conductivity of 6.67 × 10^-3 S.cm^-1 by AC impedance method. The good thermal stability suggested that PANi/PSDVB microspheres could be a promising material to replace the conventional metallic anisotropic conductive film (ACF) particles if the conductivity could be further improved in the future.     

Polymorphic behavior of nylon 6/saponite and nylon 6/montmorillonite nanocomposites

X‐ray diffraction methods and DSC thermal analysis have been used to investigate the structural change of nylon 6/clay nanocomposites. Nylon 6/clay has prepared by the intercalation of ε‐caprolactam and then exfoliaton of the layered saponite or montmorillonite by subsequent polymerization. Both X‐ray diffraction data and DSC results indicate the presence of polymorphism in nylon 6 and in nylon 6/clay nanocomposites. This polymorphic behavior is dependent on the cooling rate of nylon 6/clay nanocomposites from melt and the content of saponite or montmorillonite in nylon 6/clay nanocomposites. The quenching from the melt induces the crystallization into the γ crystalline form. The addition of clay increases the crystallization rate of the α crystalline form at lower saponite content and promotes the heterophase nucleation of γ crystalline form at higher saponite or montmorillonite content. The effect of thermal treatment on the crystalline structure of nylon 6/clay nanocomposites in the range between Tg and Tm is also discussed.