Polypropylene rubber-toughed

Polypropylene polymers are typically modified with ethylene to obtain desirable properties for specific applications. Specifically, ethylene—propylene mbbers are introduced as a discrete phase in heterophasic copolymers to improve toughness and low temperature impact resistance (see Elastomers, ETHYLENE-PROPYLENE rubber). This is done by sequential polymerisation of homopolymer polypropylene and ethylene—propylene mbber in a multistage reactor process or by the extmsion compounding of ethylene—propylene mbber with a homopolymer. Addition of high density polyethylene, by polymerisation or compounding, is sometimes used to reduce stress whitening. In all cases, a superior balance of properties is obtained when the sise of the discrete mbber phase is approximately one micrometer. Examples of these polymers and their properties are shown in Table 2. Mineral fillers, such as talc or calcium carbonate, can be added to polypropylene to increase stiffness and high temperature properties, as shown in Table 3. 

These rubbers are now also being blended on a large scale with polyolefin plastics, particularly polypropylene, to produce a range of materials which at one extreme are tough plastics and at the other the so-called thermoplastic polyolefin rubbers (TPORs) (.see Section 11.9.1). 

Grein, C. Toughness of Neat, Rubber Modified and Filled /3-Nuclealed Polypropylene From Fundamentals to Applications. Vol. 188, pp. 43-104. 

Polypropylene polymers are typically modified with ethylene to obtain desirable properties for specific applications. Specifically, ethylene-propylene rubbers are introduced as a discrete phase in heterophasic copolymers to improve toughness and low temperature impact resistance. 

Toughness of Neat, Rubber Modified and Filled /3-Nucleated Polypropylene... 

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