Effects of injection molding conditions on the electrical properties of polycarbonate/carbon nanotube nanocomposites

Abstract

Polycarbonate/Carbon nanotube (PC/CNT) nanocomposites containing various CNT contents (0–5 wt%) were prepared by injection molding. The effects of CNT contents, injection speed (V) and injection temperature (T) on the electrical resistivity of the PC/CNT nanocomposites were investigated. It was found that the tensile strength of nanocomposites was enhanced slightly with increased CNT contents, and the tensile modulus was 29% greater after the 5 wt% CNT addition, but the brittle tendency became stronger. Aside from tensile properties, the electrical resistivity of the nanocomposites dropped 12 orders of magnitude after the 5 wt% CNT addition. Also, there was a tendency that the electrical resistivity was lower in the case of higher injection temperature and lower injection speed. Scanning electron microscope (SEM) images and the distribution of surface layer electrical resistivity, clearly showed a notable influence by surface layer microstructures on the electrical resistivity, and the injection conditions affected both the value of the maximum electrical resistivity and the position where it occurred. This study offers an alternative green and simple molding process to prepare conductive PC nanocomposites and to achieve the industrialization of PC/CNT nanocomposite products which can be used in electromagnetic shielding and anti‐static fields. POLYM. COMPOS., 37:3245–3255, 2016. © 2015 Society of Plastics Engineers

Preparation and characterization of PbO/carboxymethyl cellulose/polyvinylpyrrolidone nanocomposite films

“…Polymer nanocomposites, as well as organic/inorganic hybrid nanocomposites materials gain considerable attention because of their practical interests in many applications. This is due to their unique electronic, mechanical, thermal, and optical properties . The importance of using nanoparticles as fillers is not only due to their ability to improve the final performance of the blend, but also due to their roles in enhancing the compatibility between the blend constituents .…”

Dielectric Spectroscopy of PP/MWCNT Nanocomposites: Relationship with Crystalline Structure and Injection Molding Condition

“…This is due to the shear stress induced on the molten material, by the flow during the mold-filling phase, which changes over the thickness and the surface of the mold cavity and the produced component [ 12 ]. In the case of polymers filled with conductive particles, this inhomogeneity in the morphology, results in an equivalent inhomogeneity in the electrical behavior [ 3 , 14 , 30 , 41 ]. As an example, Cesano et al [ 30 ] highlighted this effect in the thickness of PP-MWCNT nanocomposites, while Pötschke et al [ 44 ] studied this phenomenon on several positions over the surface of polycarbonate-MWCNT nanocomposites.…”

“…This was also demonstrated for CNT-based nanocomposites [ 12 ]. Several studies have shown that the variation of the processing condition of injection-molded components, manufactured with CNT-based nanocomposites, can lead to drastic modification of the electrical conductivity, especially when the CNT content is in the range of the electrical percolation [ 13 , 14 , 15 , 16 , 17 , 18 ]. Villmow et al [ 16 ] studied injection-molded polycarbonate-based CNT nanocomposites, demonstrating that lowering the cooling rate and residence time seems to favor the attainment of higher electrical conductivity.…”

Thermal behavior and mechanical properties of nanocomposites of polycarbonate reinforced with multiwalled carbon nanotubes

“…This indicates that the microhardness distribution from the surface to the interiorcould be divided into three regions—a rise, a decline, and a plateau. These phenomena might be explained as follows: when the MWCNT content was beyond 5 wt%, the MWCNTs in the core layer could more easily orient in a certain direction , and the thermal expansion coefficient of MWCNTs was lower than that of PC; thus a residual stress easily remained in the intermediate layer against with the pressure head of the meter, resulting in the enhancement of microhardness.…”