• Bertelsen, Line Hestbech
• Kybelund, Peter
• Kristensen, Mikael
• Sørensen, Martin Brorholt
• Andersen, Emil
• Salomonsen, Mathias
• Hinge, Mogens

Abstract

Pigments such as iron oxides are readily used in combination with polymers and evaluating their influence on polymer durability is important to successfully evaluate lifetime of modern polymer products. This work presents heat-treatment at 60 °C of poly(acrylonitrile butadiene styrene) (ABS) compounded with 18 different pigments, with focus on five iron and three copper complex pigments loaded in ABS. The pigments were shown to have an catalysing effect on the thermo-oxidative degradation of ABS, specifically the 1,4-poly(butadiene) phase leading to PB-phase crosslinking, resulting in embrittlement of the polymer. Attenuated total reflectance Fourier transform infrared spectroscopy showed that the oxidation of 1,4-poly(butadiene) was accelerated about six-fold after 1440 h at 60 °C, 50%RH when ABS was compounded with iron oxide based pigments (e.g. PBl11) compared to pure ABS. The degradation of the poly(butadiene) rubbery phase caused ABS to become brittle, demonstrated as a lowered strain a break and impact toughness. The impact toughness of ABS decreased up to four times more when compounded with some iron oxide and copper complex pigments, compared to pure ABS after heat-treatment at 60 °C for 1440 h. However, it was noted that some iron- and copper based pigments did not cause catalytic degradation of ABS, which may be a result of lowered surface area, chelation and sterically hindering of the metal atom. Differential scanning calorimetry oxygen-induction time was utilized to screen the ABS-pigment combination before ageing, and an oxygen-induction time below 10 min lead to significantly increased degradation of the poly(butadiene) phase in ABS.

Topics

• impedance spectroscopy
• surface
• polymer
• phase
• Oxygen
• copper
• differential scanning calorimetry
• iron
• aging
• durability
• Fourier transform infrared spectroscopy