Morphology development of EPDM/PP uncross‐linked/dynamically cross‐linked blends

Abstract

Ethylene‐propylene‐diene‐terpolymer (EPDM) and polypropylene (PP)‐based uncross‐linked and dynamically cross‐linked blends were prepared both in an internal mixer and in a corotating twin‐screw extruder. The effects of composition, plasticization and mixing equipment on the morphology development and the final viscoelastic properties were studied. In the uncross‐linked blends, the plasticization resulted in a coarser morphology. Furthermore, it was shown that the majority of the plasticizer resided in the EPDM phase, enabling its deformation in the flow direction. In addition, the intensive mixing conditions inside the twin‐screw extruder resulted in a finer morphology. In the dynamically cross‐linked blends, the twin‐screw extrusion process resulted in a higher level of gel content with larger EPDM domains. The plasticization showed again a coarsening effect, resulting in interconnected cross‐linked EPDM domains. An interesting interfacial phenomenon was observed especially in the plasticized vulcanized blends where nanometer size occluded PP domains were stripped off and eroded into the EPDM phase. With the exception of the nonplasticized uncross‐linked blends, the viscoelastic properties of all other blending systems were found to be directly affected by the morphology, gel content (in the case of cross‐linked blends), and the presence of the plasticizer. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers

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

“…The literature presents some works in which dynamic vulcanization is analyzed during processing into internal mixer [22,[37][38][39][40][41][42][43][44] , as performed on this work. In this particular case, the influence of a clay addition in the dynamic revulcanization reaction is analyzed.…”

Blends of ground tire rubber devulcanized by microwaves/HDPE - Part A: influence of devulcanization process

“…Some researchers use this advantage to examine different phenomena such as dynamic vulcanization [21][22][23][24][25][26][27][28][29] , as performed in this work. During the mixing, just after the addition of the matrix phase and as soon as the torque measured by the equipment was stabilized, GTR (containing or not vulcanization additives) was added into the mixer, what permitted the analysis of the dynamic revulcanization behavior of the blends, which is shown in Table 3.…”

“…According to Shahbikian et al [21] , the advantage of using internal mixer to produce TPV is the possibility of monitoring the effect of each component on the torque/temperature evolution of the blend. Some researchers use this advantage to examine different phenomena such as dynamic vulcanization [21][22][23][24][25][26][27][28][29] , as performed in this work.…”

The use of atomic force microscopy as an important technique to analyze the dispersion of nanometric fillers and morphology in nanocomposites and polymer blends based on elastomers

“…Even not being the aim of this work, but to reinforce the range of AFM technique, some authors use it for the study of morphology of blends type Elastomer Thermoplastic (TPE) and Thermoplastic Dynamic Vulcanizate (TPV) [17,24] . Shahbikian et al [24] made a comparative study on the morphology development and the viscoelastic properties of uncross-linked and cross-linked EPDM/PP-based TPEs.…”

“…Shahbikian et al [24] made a comparative study on the morphology development and the viscoelastic properties of uncross-linked and cross-linked EPDM/PP-based TPEs. The blends were prepared by using an internal mixer and a co-rotating twin screw extruder.…”