Dynamically vulcanized blends of polypropylene and ethylene‐octene copolymer: Comparison of different peroxides on mechanical, thermal, and morphological characteristics

Abstract

Thermoplastic vulcanizates (TPVs) are prepared by the dynamic vulcanization process, where crosslinking of an elastomer takes place during its melt mixing with a thermoplastic polymer under high shear. TPVs based on polypropylene (PP) with different grades of ethylene-octene copolymers (EOC) were prepared with a coagent assisted peroxide crosslinking system. The effect of dynamic vulcanization and influence of various types and concentrations of peroxide were mainly studied on the basis of the mechanical, thermal, and morphological characteristics. Three structurally different peroxides, namely dicumyl peroxide (DCP), tert-butyl cumyl peroxide (TBCP), and di-tert-butyl peroxy isopropyl benzene (DTBPIB) were investigated. The mechanical properties of the TPVs are primarily determined by the extent of crosslinking in the EOC and the degree of degradation in the PP phase. Among all peroxides used DCP gives best overall properties with low-molecular-weight EOC, whereas TBCP shows best property level with high-molecularweight EOC-based TPVs. These can be explained on the basis of the molecular characteristics of EOC and the nature of the peroxide used. Differential scanning calorimetery (DSC) and morphological analysis reveal that PP and EOC are a thermodynamically immiscible system. The melting endotherm was studied to determine the influence of various peroxides on crystallinity of the PP phase. Tensile fracture patterns were also analyzed to study the failure mechanism of the samples.

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

“…This study reveals the positive influence of the EIReP in the preparation of TPVs and paves a new technology for the development of various types of TPVs in an eco‐friendly direction. The authors' earlier work reported the influence of three different peroxides36 and different co‐agents37 on 30:70 blend ratio of peroxide cured PP/EOC TPVs. The readers can refer the results of peroxide‐based TPVs to understand the divergence in the performance properties and morphological evolution.…”

Effect of surface modification of titanium dioxide on the UV‐C aging behavior of silicone rubber

“…The crosslinking density (D) was calculated according to the well-known Flory-Rehner equation as follows 26 : The samples before or after the UV-C aging that were weighed as m 0 were immersed in toluene at 20 C for 48 h to achieve the swelling equilibrium.…”

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

“…G' is influenced also by morphology of the blends [28,37] . The morphology refinement and compatibility tend to increase the G' values.…”