The Effect of Waste Fodder Potato Proteins on the Mechanical Properties of Carboxylated Acrylonitrile-Butadiene Rubber

The current investigation treats about the influence of waste fodder potato proteins (WFPP) recovered from the starch industry on the mechanical-properties of carboxylated acrylonitrile-butadiene rubber (XNBR). WFPP were characterized and used as a filler of the above mentioned XNBR rubber without or after blending with zinc oxide. The obtained rubber compounds were cured, and mechanical properties such as tensile strength, hardness, and cross-linking density were investigated. It was found that the introduction of WFPP previously blended with zinc oxide into rubber compound increases the cross-linking density of the obtained composites, compared with the vulcanizate without protein, which in turn increases the mechanical properties of the obtained vulcanizates. That occurs thanks to the formation of ion nodes, as testified by equilibrium swelling. The introduction of WFPP into the elastomer matrix also increases the susceptibility of the elastomer to biodecomposition. 1. Introduction Reviewing the literature, it is easy to notice that biodecomposable rubber materials are not produced in large quantity. One of the biggest problems of the modern industry, which is dominated by polymers, is the excessive production of waste. That waste needs to be eliminated or, at least, reutilized. The aim of this paper is to obtain a new functional rubber compound with good properties which is susceptible to undergo biodecomposition in natural environment thanks to the introduction of waste potato proteins into an elastomeric matrix. The obtained rubber compound fulfils the two aims mentioned above: it reutilizes waste (potato proteins) and it is biodecomposable. As a result, the material can be easily eliminated from the environment. At this point, it is important to define the meaning of biodecomposition. Biodecomposition, unlike biodegradation, does not lead to complete degradation into water, carbon dioxide, and humus. In this paper, biodecomposition refers to the decomposition of the protein filler which provides for degradation of the structure of the material, resulting in worse mechanical properties. The material loses its functionality and can more easily be decomposed into pieces under the influence of mechanical and natural factors. The proteins contained in potatoes are a byproduct in starch production and are considered as a waste, in quantities of about 200 thousand tons per year. Usually, these proteins are used as a component of fodder mixtures for animals, simultaneously replacing animal proteins. Potato proteins are a rich source of nutritious