Bernt-Åke Sultan

Influence of the structure of acrylate groups on the flame retardant behavior of ethylene acrylate copolymers modified with chalk and silicone elastomer

This study treats the flame retardant effects of different ethylene acrylate copolymers used in a chalk and silicone elastomer system, specifically the flame retardant chemistry and behavior at lower temperatures. The presence or absence of ester pyrolysis, formation of ionomers or other crosslinks, viscosity, and the effects of these factors on the formation and stability of the intumescent structure formed during heating are discussed. The effects of the acrylate content and melt flow rate in flame retardant compounds based on ethylene butyl acrylate copolymer and ethylene ethyl acrylate copolymer are examined. Results of oxygen index, cone calorimetry (including visual observations), dripping, viscosity measurement, thermogravimetric analysis, and infrared spectroscopy are reported.

Surface modification of polyethylene to improve its adhesion to aluminum

The effects of surface modification of polyethylene (PE) and aluminum on the adhesion strength have been investigated. PE was modified by KMnO4/H2SO4 treatment followed by adsorption of different cations, Ca2+, Ba2+, and Zn2+. The aluminum surface was treated with alkali and was also modified by adsorption of titanates. The surfaces were characterized by means of multiple internal reflection (MIR) IR and ESCA. The adhesion strength was measured by the T-peel test. Both ESCA and MIR analyses show the presence of hydroxyl, carbonyl, ester, and carboxyl groups on the KMnO4/H2SO4-treated PE surface. In addition, sulfate and sulfonate groups are present. The sulfonate groups are apparently localized in crevices extending beneath the ESCA sampling depth of 50 A. Vinylidene groups are also present on the surface. Cation adsorption on the oxidized PE surface seems to be determined by the solubility constant of the corresponding sulfate salts and is in the order Ba2+ > Ca2+ > Zn2+. Adsorption of Ca2+ and Ba2+ incr...