Grazyna Janowska

Effect of halogenless flame retardants on the thermal properties, flammability, and fire hazard of cross-linked EVM/NBR rubber blends

This paper presents the results of investigating the thermal stability, flammability, and fire hazard of cross-linked EVM/NBR blends unfilled and filled with halogenless flame-retardant compounds such as melamine cyanurate or magnesium hydroxide. The thermal analysis of the blends was carried out in the atmosphere of air. The activation energy of the composite destruction was determined by two non-isothermal methods: Flynn–Wall–Ozawa’s and Kissinger’s methods. The flammability of the composites obtained was determined by the method of oxygen index and on the basis of their combustion in air. The fire hazard of the vulcanizates investigated was determined with the use of a cone calorimeter and on the basis of toxicometric parameters WLC50SM. The test results have shown that the flame retardants used increase the thermal stability of the cross-linked blends and decrease their flammability, and thereby allow one to obtain self-extinguishing or non-flammable polymeric materials. The cross-linked EVM/NBR blends filled with these flame-retardant compounds are characterized by good mechanical properties and reduced fire hazard.

The thermal properties and the flammability of pigmented elastomeric materials

This paper presents thermal properties of organic pigments such as zinc phthalocyanine and chloroaluminum phthalocyanine that were synthesized according to the literature data. These pigments were characterized by means of elementary analysis and measurements of particle size. They were then incorporated into butadiene-styrene rubber and butadiene-acrylonitrile rubber. The elastomeric mixtures were cross-linked by two methods: using organic peroxide or sulfur. The effect of phthalocyanines on the thermal properties, flammability, and fire hazard of the pigmented polymeric materials obtained as well as on their mechanical properties and cross-linking degree was studied. It has been shown that the phthalocyanine pigments not only impart appropriate esthetic values to the final goods but also increase their thermal stability and considerably reduce the flammability and fire hazard of elastomers and even make possible materials that are self-extinguishing under air atmosphere. These pigments also have a beneficial influence on the degree of cross-linking of the elastomers investigated and their mechanical properties.

Mineral Nanofillers Obtained via Cryogenic Deaggregation Method

Abstract. The paper presents a new method for the modification of silica causing an increase in its activity. The use of an adequate well-chosen dispersing agent brings about cleavage of filler aggregates as primary particles, the greater part of which is within the nano range. The application of the modified silica improves the mechanical properties of vulcanizates and limits their flammability. The method is based on violent freezing of silica impregnated with water, or an aqueous solution of dispersing agent, and is is of importance from the technology and material engineering points of view.