Blends of polystyrene and high-density or linear low-density polyethylene have been prepared in an internal mixer and studied in a wide range of compositions. Phase inversion compositions have been determined using selective extraction and scanning electron microscopy. It appears that phase inversion can occur in a domain of compositions rather than at a single point. The existing models of phase inversion are not complete enough to explain the entire phenomenon, and percolation of each component may be considered to describe the formation of co-continuity.

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Among the waste generated in leather processing, proteic and lipidic compounds are particularly dominant. Enzymes, like proteases and lipases, have an important role in biodegradation of collagen, keratin and fats in leather waste. Present investigation deals with isolation, selection and characterization of proteolytic and lipolytic microorganisms in order to perform biodegradation of waste from leather industry. The inoculum of microorganisms was sampled from old waste storage dump leather. The proteolytic microorganisms were isolated using screening method in presence of casein and gelatin substrate type, respectively. The microorganisms that secrete the lipolytic enzymes were isolated using medium that contained the Tween 80. These microorganisms identified by microscopic analysis can be used for improvement of waste leather biodegradation process.

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