Fillers their effect on the failure modes of plastics

Crazes are similar to cracks, the opposite sides of which are connected with fibres of oriented polymer material. In filled polymers, crazes are caused by debonding of particles and by stretching of the polymer in 

Unstable neck Stable neck propagation propagation 

The mechanical properties of elastic materials are characterized by ultimate fracture stress (strength), fracture strain, and Young s modulus (the ratio of stress to strain). The mechanical response of ductile materials is non-linear and their properties are additionally characterized by yield stress and draw stress (also called lower yield stress) if a polymer yields with necking. The cross-sectional area of a specimen reduces during yielding, and stress is calculated as a ratio of an applied force to the initial cross-section (engineering stress) or to the current cross-section of the specimen (true stress). Here engineering stresses are used. 

Fillers their effect on the failure modes of plastics 

Eigure 5 illustrates the effect of particles on the relative yield stress Uy of filled polymers. The yield stress is within the dashed fork region depending on adhesion between the polymer and the particles. The upper border of the fork is a constant, equal to the yield stress of the unfilled polymer cTym (the case of small particles of nanometre size, when the yield stress 

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The subject of rubber as a filler is dealt with in the entry entitled Surface-modified rubber particles for pol)nirethanes. Hydrated alumina, otherwise known as alumina trihydrate (ATH), is considered under the heading Flame retardants inorganic oxide and hydroxide systems. Some mechanical property considerations are dealt with in the entry entitled Fillers their effect on the failure modes of plastics. ... 

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