Morphology and crystalline properties of impact‐modified polypropylene blends

Abstract

Isotactic polypropylene has been reactively blended with an ethylene‐octene copolymer so as to improve mechanical and rheological properties. Free radical polymerization of styrene and a multifunctional acrylate during melt extrusion has resulted in the formation of unique features in both amorphous and crystalline phases. Transmission electron microscopy images show that the elastomer domains are less than 200 nm in diameter, whereas grafting leads to the appearance of clusters of polymeric particles, ranging in size from several nanometers up to 200 nm. Differential scanning calorimetry (DSC) shows that grafting creates lamellar crystals that melt at much lower temperatures and recrystallize at much higher temperatures than binary blends. From wide angle X‐ray diffraction and DSC, grafting has been shown to limit the maximum crystal size and perfection, as well as broaden the size distribution of the crystals. Grafting causes significant changes in the α crystalline phase of polypropylene and promotes the formation of the β phase. Scanning electron microscopy reveals a unique cross‐hatch structure of small crystals in the reactive blend, with tangential and radial lamellae appearing as crosslinked material of about the same aspect ratio. Polarized light microscopy gives evidence that grafting and branching within this blend causes a gelation‐like recrystallization. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers

Sustainable Materials: Value-Added Composites from Recycled Polypropylene and Fly Ash Using a Green Coupling Agent

“…The Bragg reflections were observed at around 2θ = 14.1°, 16.8°, 18.5°, 21°, and 22°, respectively, which were similar to that of polypropylene, and these positions corresponded to the indexed planes of α monoclinic planes of (110), ( 040), ( 130), (111), and (131), respectively. 17,22 The characteristic peaks of fly ash, both in surface coated and uncoated forms, were observed at 2θ = 26.6°. In the composites, a reduction in peak intensity and sharpness was evident as a result of lessening in the amount of the polymer matrix.…”

Morphology and mechanical properties of impact modified polypropylene blends

“…A second paper on this research describes the crystalline nature of these materials and explains that Blend C is composed of relatively small (submicron) polypropylene crystals in the presence of submicron elastomer particles [66]. A unique transcrystalline interface is known to decrease plastic resistance and alter energy absorption and dissipation mechanisms [67,68].…”

Deposition of Ureido and Methacrylate Functionalities Onto Silica Nanoparticles and its Effect on the Properties of Polypropylene-Based Nanodielectrics

“…crosslinked polyethylene (XLPE) [6]. The absence of crosslinking by-products in PP-based nanodielectrics results in an improved space charge accumulation, and their thermoplastic nature allows for a more sustainable end-of-life for these materials [6][7][8][9]. This class of dielectric nanocomposites also exhibit good mechanical properties, comparable to XLPE, which makes them a reliable candidate for high voltage direct current (HVDC) cable insulation systems [10][11][12].…”