P(AN-VAc-PMMT) nanocomposites were prepared using
In recent years, a significant amount of work has been carried out on polymer-clay nanocomposites because they show more favorable mechanical properties than pure polymers and conventional inorganic-polymer composites [
Electrospinning is an effective method for the production of polymeric fibers [
The purpose of this project was to improve the thermal properties of PAN-based fibers via electrospinning. Specifically, this paper describes the formation of electrospun fibers from solutions of poly (AN-co-VAc) copolymers and dispersions of their layered-silicate nanocomposites. Fibers have also been formed under the same conditions. The nanocomposites were prepared using
A certain amount of acetone, chloromethyl styrene, and dodecyl dimethyl amine was added to a 250 mL three-neck bottle equipped with a stirrer, reflux condenser, and thermometer. It was heated until the acetone was refluxed. A yellow emulsion was produced after 2 hours. The product was precipitated by n-heptane and then washed with acetone three times. After centrifugation, the sediment was washed with deionized water, dried in vacuum at 60°C for 24 hours, and ground into fine powder.
One gram of Na-MMT was dispersed in 30 mL of distilled water with vigorous stirring for 0.5 hours at room temperature. Three-tenths of a gram of methyl styrene dodecyl quaternary ammonium was dissolved in 20 mL of distilled water. The two solutions were mixed under nitrogen and kept at 80°C with stirring at 800 rpm for 3 hours. After centrifugation, the sediment was washed with deionized water, dried in a vacuum at 80°C for 24 hours, and ground to a fine powder.
The P(AN-co-VAc) copolymers containing 10 wt% VAc and layered-silicate nanocomposites with the same nominal compositions were prepared individually via emulsion polymerization.
Details follow: a given weight of PMMT was dispersed in admixture of 9 g acrylonitrile (AN) and 1 g vinyl acetate (VAc). The solution was surged ultrasonically for 30 minutes when the ultrasonic frequency was 400 KHz and ultrasonic power was 250 W. 90 mL deionized water and 0.2 g sodium dodecyl benzene sulfonate (SDBS) were placed in a three-neck bottle with a battle stirrer, a reflux condenser, and a thermometer. The solution was mixed thoroughly and then added to a PMMT and polymerizable quaternary ammonium ion monomer mixture while being continuously mixed by ultrasonic. When the temperature reached 70°C, the solution of K2S2O8 was added to the three-neck bottle and allowed to react for about 2 hours. Then it was swilled into beakers and various 13 wt% NaCl solutions were added to the beakers to precipitate the product. After centrifugation, the sediment was washed with deionized water, dried in a vacuum at 70°C for 24 hours, and ground to a fine powder.
P(AN-VAc-PMMT) composites prepared by
TEM of P(AN-VAc-PMMT) ((a) 2%, (b) 5%).
The spectrum contained characteristic absorbance bands of all components. The spectrum of pure MSDQA (Figure
FTIR spectra of (a) MSDQA and (b) P(AN-VAc-PMMT).
As shown in Figure
XRD: (a) Na-MMT and PMMT; (b) 1: the PMMT content 5 wt%, 2: the PMMT content 8 wt%, and 3: PMMT.
Fiber morphology was characterized using SEM. Figure
SEM images of P(AN-VAc-PMMT) ((a) 0%, (b) 2%) electrospinning fibers processed in a capillary tube with an inner diameter of 0.7 mm at a voltage of 30 KV, a spinning distance of 25 cm, and a speed of 0.5 mL/h.
Figure
P(AN-VAc-PMMT) nanocomposites were prepared by the method of emulsion intercalation polymerization. It is a result that P(AN-VAc-PMMT) nanocomposite was synthesized token by FTIR spectra and the copolymer P(AN-VAc) is intercalated into montmorillonite layer by XRD. P(AN-VAc) and P(AN-VAc-PMMT) composites can be made into nanofibers by electrospinning. The electrospinnability of P(AN-VAc) fiber composites was found to be better than that of P(AN-VAC).
The authors declare that they have no direct financial relation with the commercial identities mentioned in this paper that might lead to a conflict of interests for any of them regarding the publication of this paper.
This work was supported by the National “Eleventh Five-Year” Technology Support Program Foundation (2006BAD10B08) and the Natural Science Foundation of Hebei Province (E2009000448).