Use of Functionalized Polyolefin Blends

The major field of application of functionalized PO blends and functionalized homo-polyolefins is compatibilization of blends of condensation polymers. The use of functionalized PO blends, in place of homopolyolefins, has a number of advantages. First, by ratio variation of PO in the blend, it is possible to change the degree of microheterogeneity of the final product this fact is of importance for impact strength (67). Second, the selective nature of grafting can be useful in controlling the functionalization power of one or another component in PO blends. 

Additions of different types of PO can be used to control the mechanical characteristics of the blends, the melt viscosity of functionalized PO blends, their high elastic properties, which is important for widening the technological opporffi-nities and the properties of composites. Of no lesser importance is the fact that an introduction of a cheaper component into functionalized PO blends is economically 

In addition to the above-mentioned fields of application, functionahzation of blends of olefin polymers and copolymers has been widely employed in the manufacture of thermoplastic dynamic vulcanizates (71,72). 

The analysis of experimentally obtained data on free-radical grafting (at RE) of unsamrated polar monomers to blends of PP/PE, PP/EPR, PE/EPR, PP(PE)/ECO, and PP(PE)/styrene polymers has indicated that there is a number of features that distinguish this process from the functionahzation of homopolyolefins. 

To ensure satisfactory grafting to each of the components making a PO blend, it is reasonable to use peroxide initiators that have a stronger affinity with these components. In case of a great difference in the solubility parameters of the components, it seems reasonable to use a mixture of initiators that do not react chemically between themselves but are soluble in certain PO components. When monomers are chosen for grafting, 1,2-disubstituted ethylenes should be preferred because they are not disposed to homopolymerization and show a weak thermodynamic affinity with the peroxide initiator. 

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