Structure and Properties of Multiwall Carbon Nanotubes/Polystyrene Composites Prepared via Coagulation Precipitation Technique

I N Mazov,V L Kuznetsov,V I Suslyaev,D V Krasnikov,V A Zhuravlev,O B Anikeeva,N A Rudina,E Yu Korovin,A I Romanenko

doi:10.1155/2011/648324

Abstract

Coagulation technique was applied for preparation of multiwall carbon nanotube- (MWNT-)containing polystyrene (PSt) composite materials with different MWNT loading (0.5–10 wt.%). Scanning and transmission electron microscopies were used for investigation of the morphology and structure of produced composites. It was shown that synthesis of MWNT/PSt composites using coagulation technique allows one to obtain high dispersion degree of MWNT in the polymer matrix. According to microscopy data, composite powder consists of the polystyrene matrix forming spherical particles with diameter ca. 100–200 nm, and the surface of MWNT is strongly wetted by the polymer forming thin layer with 5–10 nm thickness. Electrical conductivity of MWNT/PSt composites was investigated using a four-probe technique. Observed electrical percolation threshold of composite materials is near to 10 wt.%, mainly due to the insulating polymer layer deposited on the surface of nanotubes. Electromagnetic response of prepared materials was investigated in broadband region (0.01–4 and 26–36 GHz). It was found that MWNT/PSt composites are almost radiotransparent for low frequency region and possess high absorbance of EM radiation at higher frequencies.

Highlights

Carbon nanotubes attract high attention as perspective material due to their high mechanical strength, Young’s modulus, thermal and electrical conductivity, and chemical stability
In recent decade many works were done in the field of the development of preparation techniques and investigation of properties of multiwall carbon nanotube- (MWNT-)reinforced plastic composites, based on such matrices as epoxy resin [4], polymethylmethacrylate [5], polyurethanes [6], polystyrene [7], and polypropylene and polyethylene [7, 8] Nowadays several preparation methods were successfully used for synthesis of CNT-containing composites, melt mixing [9], solvent cast technique [10], in situ polymerization [11, 12], coagulation precipitation [13], and so forth
The typical TEM image of multiwall carbon nanotubes (MWNT) used for synthesis of composites is shown on Figure 1

Summary

Introduction

Carbon nanotubes attract high attention as perspective material due to their high mechanical strength, Young’s modulus, thermal and electrical conductivity, and chemical stability. In recent decade many works were done in the field of the development of preparation techniques and investigation of properties of MWNT-reinforced plastic composites, based on such matrices as epoxy resin [4], polymethylmethacrylate [5], polyurethanes [6], polystyrene [7], and polypropylene and polyethylene [7, 8] Nowadays several preparation methods were successfully used for synthesis of CNT-containing composites, melt mixing [9], solvent cast technique [10], in situ polymerization [11, 12], coagulation precipitation [13], and so forth Among these methods coagulation precipitation technique described by Du et al [14] is one of the most promising because of its experimental simplicity, potential scalability, and ability for usage for synthesis of various thermoplastic-based polymer composites. In the present work coagulation precipitation technique was applied for preparation of MWNT-containing polystyrene composites with various CNT content, and investigation of their morphological, structural, electrophysical, and electromagnetic properties was performed

Experimental and Methodology

Results and Discussion

Conclusions