Mechanical and optical effects of elastomer interaction in polypropylene modification: Ethylene-propylene rubber, poly-(ethylene-co-octene) and styrene-butadiene elastomers

Abstract

Abstract.The interaction between binary combinations of three different elastomer classes commonly applied in impact modification of isotactic polypropylene (iPP) was studied. Blends based on a homogeneous ethylene-propylene (EP) random copolymer (EP-RACO) and a heterophasic EP impact copolymer comprising ethylene-propylene rubber (EPR) with different external elastomer types, one homogeneous ethylene-1-octene copolymer (EOC), and two hydrogenated styrenebutadiene-styrene triblock copolymers (SEBS) with different styrene content, were prepared. The phase morphology, mobility as a function of temperature, mechanical and optical properties were studied. Special effects could be achieved for the combination of two different elastomer types. The results clearly demonstrate the possibility to achieve attractive property combinations in ternary systems consisting of a crystalline PP matrix and two different types of elastomer, EPR or EOC on the one hand and SEBS on the other hand. A combination of density matching and compatibilization effects allows reaching good low temperature impact strength together with a transparency close to matrix level when selecting a butadiene-rich SEBS type.

Crosslinked Continuous Glass Fiber‐Reinforced Toughened Polypropylene Composites

“…Consequently, the low-molecular and low-modulus components of the sizing act as softener and the improvement in interfacial adhesion is limited in comparison to thermosets. [15,16] Since non-reactive blending of PP with rubber leads to a blend with a lower level of E-modulus and tensile strength, [17] we used the electron-induced reactive processing. This can be achieved by a free radical process or by a metallocene catalyzed in situ copolymerization onto the fiber.…”

Polypropylene and polypropylene-elastomer blends for medical packaging

“…The toughness improvement for SEBS modified PP-R/Bs was not as pronounced as in the case of PP-R-2. According to literature [9], this originates from the fact that the particle size of PP-EPR systems remains more or less unchanged when modified with a butylene-rich SEBS. This results in an improvement of the toughness at ambient conditions but leaves the toughness at sub-ambient temperatures more or less unchanged.…”

Influence of network structure on the viscoelastic properties of dynamically vulcanized rubber/plastic blends: An alternative approach to understand the microstructure evolution

“…Rubbers and TPEs being viscoelastic in nature show "creep" behavior when subjected to a constant stress. The stress-strain curves are modeled by Kelvin and Voigt as [34], (8) where J(t) and J 0 are the creep compliance after time t and instantaneous creep compliance, and J i and τ i are the constants characteristic of the system. The strain-time plot for the TPVs is given in Figure 19 which shows good coherence with the characteristic strain-time plot for viscoelastic materials and depicts the representative strain response to creep and recovery for the respective TPVs.…”