Melt viscoelastic properties of peroxide cured polypropylene‐ethylene octene copolymer thermoplastic vulcanizates

Abstract

The dynamic viscoelastic properties of uncrosslinked and dynamically crosslinked blends of polypropylene (PP) and ethylene octene copolymer (EOC) were investigated in the melt state to study the mechanism of reinforcement, influence of particle size, and kinetics of modulus recovery. Dynamic vulcanization was performed by coagent assisted peroxide crosslinking system. Addition of peroxide in PP/EOC blend involves two major competing reactions: crosslinking in EOC and degradation of PP by β chain‐scission. In this article, morphological and melt rheological properties of the TPVs were studied with special reference to the effect of mixing protocol. Three different mixing techniques were investigated. They are: (i) conventional or preblending method—melt mixing of PP and EOC followed by dynamic vulcanization (ii) phase mixing method—curative master batch of EOC added on the molten PP (iii) split addition of PP—preblending method followed by addition of half part of PP (dilution procedure). The type of mixing protocol has a significant influence on the rheological behavior. Rheological properties have been evaluated at the processing temperature (180°C) in a Rubber Process Analyzer (RPA 2000). A variety of rheological observations such as Payne effect, modulus recovery and shear rate sensitivity were studied by carrying out frequency and strain amplitude sweeps. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers

Electron‐Induced Reactive Processing of Poly(propylene)/Ethylene–Octene Copolymer Blends: A Novel Route to Prepare Thermoplastic Vulcanizates

“…Appearance of the plateau region in the low frequency region results from the formation of highly ordered structure or network structure. In case of TPVs, the crosslinked EOC particles form a 3D network‐structure embedded in the PP matrix by segmental interdiffusion mechanism 12. It can be postulated that the network structure, mainly aggregates/agglomerates of crosslinked rubber particles tend to collapse and deform to exhibit higher shear thinning behavior.…”

“…The blend was hydrolyzed and water crosslinked in a twin screw extruder. The authors' earlier work focused on the preparation of peroxide cured PP/EOC TPVs with special attention to understand the reinforcement mechanism through melt rheological characterization techniques 12. Furthermore, it was found that peroxide cured PP/EOC TPVs in presence of a co‐agent showed better melt and solid state properties when compared with peroxide‐crosslinked PP/EPDM TPVs 13…”

Blends of ground tire rubber devulcanized by microwaves/HDPE - Part B: influence of clay addition

“…According to the literature [47,51,53] , flattening of the curve G' is due to the three-dimensional network formation. In nanocomposites, this behavior is observed in systems with intercalated and/ or exfoliated structures, and this is known as pseudosolid behavior [54] .…”

Interrelationships of morphology, thermal and mechanical properties in uncrosslinked and dynamically crosslinked PP/EOC and PP/EPDM blends

“…Lai et al [16] investigated the fracture behavior and physicomechanical properties of peroxide cured PP/EOC TPVs. As a part of the extensive research work on the peroxide cured PP/EOC TPVs, our earlier report deals with the influence of different peroxides [17], different coagents [18] and different mixing sequences [19,20] on the solid and melt state viscoelastic properties of PP/EOC TPVs. The present study primarily aims to evaluate the performance of the coagent assisted peroxide cured PP/EOC TPVs as a potential alternative to the conventional PP/EPDM TPVs.…”