Comparison of Three Interfacial Conductive Networks Formed in Carbon Black-Filled PA6/PBT Blends

Abstract

Interfacial localization of carbon fillers in cocontinuous-structured polymer blends is well-known as a high-efficiency strategy for conductive network formation. However, a comparison with interfacial localization of carbon fillers in sea-island-structured polymer blends is lacking. Here, three types of highly efficient conductive networks formed on the basis of interfacial localization of carbon black (CB) in polyamide 6 (PA6)/poly(butylene terephthalate) (PBT) blends with different blend compositions (80/20, 50/50 and 20/80 vol/vol) were investigated and compared in terms of electrical resistivity, morphology as well as rheological and mechanical properties. The order of the electrical percolation threshold of CB in the three blends is 50/50 < 20/80 < 80/20, which can be attributed to different network structures. The rheological percolation thresholds are close to the electrical ones, confirming the formation of CB networks. The formation mechanisms for the three types of CB network structures are analyzed. All the three types of PA6/PBT-6 vol% CB composites showed improved tensile strength compared with PA6/PBT blends, being in favor for practical applications.

Fibers of Thermoplastic Copolyamides with Carbon Nanotubes for Electromagnetic Shielding Applications

“…Only nanofillers well-dispersed in the polymer matrix result in the formation of a percolation network able to conduct electric current and shield electromagnetic waves. Due to the modification of the processing parameters, the state of nanofillers' dispersion can be controlled, and the final composite properties have a tunable morphology [17,18]. This, together with the chemical and corrosion resistance, low weight, flexibility, ease of processing into various shapes, and inexpensiveness, is why polymer composites have the potential to replace the metallic materials in EMI shielding applications [2,17,[19][20][21][22][23][24].…”

Conductive Plastics from Al Platelets in a PBT-PET Polyester Blend Having Co-Continuous Morphology

“…In our experience of other blends such as PP-PET, in compositions such as 60:40 and 50:50, a co-continuous morphology with sharper contrast is obtained even without selective etching, and the domain sizes are in the range of 5–10 μm instead of 500 nm. Li et al’s work [ 10 ] on carbon black in PA6/PBT blends showed a very good example of a co-continuous morphology with 50:50 PA6:PBT; contrast was improved by etching the PBT component with alcoholic KOH. However, the phase domains were tens of microns in width, rather than 500 nm or lower as in 60/40 PBT/PET ( Figure 14 b).…”

“…Mamunya et al [ 7 ] had shown that on compression moulding of poly(vinyl chloride) powder with metal particles, the condition for the formation of the ‘segregated network’ was that the conductive particle should be very much smaller in diameter than the polymer particle. Likewise, in cases where a segregated network was achieved with conductive particles in a polymer blend, such as the work of Li et al [ 10 ] using carbon black in a PA6/PBT blend, the conductive particles (carbon black) had dimensions of ~100 nm while the polymer domains in the blend (whether it was sea-island or co-continuous) were typically several microns in size. This allowed the conductive particles to nestle in the regions between domains.…”

“…Immiscible blends with about equal amounts of two polymers form a co-continuous morphology and the interfacial positioning of the conductive filler is ideal for segregated network formation because the interface area is small, and it leads to the possibility of ‘double percolation’ [ 9 ]. This concept of a ‘segregated network’ formed by a conductive filler in polymer blends with co-continuous morphology has been demonstrated, for example, by Li et al [ 10 ] with carbon black in a co-continuous PBT/polyamide 6 blend and Bai et al [ 11 ] with graphene in a co-continuous blend of polylactide and poly(ethylene- co -vinyl acetate).…”

Conductive polycarbonate composites prepared by a ternary polymer blend approach involving sea‐island‐type interfacial carbon black networks

“…It is well-known that forming interfacial networks of conductive fillers in polymer blends is a high-efficiency approach to decrease conductive filler loadings. 14,[17][18][19][20][21][22][23][24][25][26][27][28][29][35][36][37][38][39][40][41] However, it is hard to construct interfacial networks of CB in PC-based binary blends because up to now it is impossible to find another polymer that has counterbalanced interaction with CB to PC. In our previous work, 39 we found that CB could form high-efficiency sea-island-type interfacial networks in poly(m-xylene adipamide) (MXD6)/poly(ethylene terephthalate) (PET) blends.…”