The effects of carbon black(s) and surfactants on the rheological properties of poly(ethylene terephthalate) as determined by a Brabender Plastograph
The effects of carbon black(s) and surfactants on the rheological properties of poly(ethylene terephthalate)
as determined by a Brabender Plastograph
Polimery 1998, No 10, 619
Channel (acidic) or furnace (alkaline) dispersed blacks stabilized with ionic or nonionic surfactants are used to dye PET on polymerization. The rheological properties of PET were examined in a Brabender Plastograph in relation to black type (Table 2) and surfactant added. Poly(N-vinylpyrrolidinone) (PVP) and 2-naphthalenesulfonic acid–formaldehyde condensate (Matexil DAAC) were used as the nonionic and ionic surfactants, respectively (Table 3). PVP used alone was found to reduce the torque (M) of the molten PET in the Plastograph, whereas Matexil DA-AC alone increased the torque. In the presence of a dispersed black, the surfactants had a similar effect (Table 5); M rose as the black particle size was increased and diminished as the degree of oxidation of the surface of the black (in terms of the WDP-coefficient, eqn. 1, Table 5) was increased. Thermal degradation of PET (M decreasing) increased as the degree of oxidation, black's surface area and additive content were increased. PVP degraded PET slightly more than Matexil did.
Keywords: polyethylene terephthalate, rheological properties, carbon black, surfactants, Brabender Plastograph