Polymer matrix resin, undesirable

Improvements of some of the end-use properties are generally obtained with the simultaneous worsening of other end-use properties. For instance, rubber particles (ethylene/propylene copolymers) are usually introduced into homopropylene matrixes in order to increase the impact resistance of polypropylene resins. However, this normally causes the decrease of the flexural modulus of the polymer blend, which is often undesirable [ 1 ]. Therefore, optimum operation conditions can only be defined in terms of a tradeoff among the many end-use properties that are required for a specific final apphcation. 

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