Morphological characterization of branched PP under stretching

Abstract

An effective approach to achieve high-melt strength polymer is to add long chain branches onto backbone species using gamma radiation. Grafting and branching result from macroradicals combinations during the irradiation process. Polypropylene films were prepared starting with irradiation process of the pellets with a 60 Co source at doses of 5, 12.5, and 20 kGy under acetylene to improve melt strength and drawability. After irradiation, polypropylene films were obtained by compression molding, at 190°C and pressure of 80 bar, and dive into a water tank at 23°C, which generally favors the formation of an amorphous phase. The thin films were stretched at 170°C using a universal testing machine. Film surface morphology and the thermal properties, were analyzed, using atomic force microscopy, scanning electron microscopy and differential scanning calorimetry. We had a different molecular structure that requested the study of their micro and nanostructure. The results showed some evidence of fibrillar structures containing crystallites and gel formation. Fibrils oriented along the stretching direction were observed.

Development of a nanocomposite of polypropylene with biocide action from silver nanoparticles

“…An increase in the gel percentage was observed with dose. The developed radiation process allowed the production of branched PP on the basis of the grafting of long‐chain branches on the PP backbone with acetylene as a crosslinking promoter under a γ‐radiation process …”

“…The developed radiation process allowed the production of branched PP on the basis of the grafting of long-chain branches on the PP backbone with acetylene as a crosslinking promoter under a c-radiation process. 36 The PP, when modified with 12.5 kGy, showed a reduction of MFI, from 1.5 6 0.1 to 0.9 6 0.1 dg/min. This was indicative of the crosslinked and/or branched material, 28 and this corroborated the increase in gel content from 1.14 6 0.10 to 2.27 6 0.10%.…”

AgNPs polypropylene gel films–thermal study and antibacterial activity

“…The irradiation process of the pellets placed in nylon bags with acetylene [20,21] was accomplished in a 60 Co gamma source from CBE at dose rate of 5 kGy h -1 . The polypropylene irradiation was performed at 12.5 kGy dose monitored by a Harwell Red Perspex 4034 dosimeter.…”

Nanocomposites of irradiated polypropylene with clay are degradable?

“…Grafting of long-chain-branches on PP backbone using acetylene as a crosslink promoter was developed for production of branched PP under gamma radiation process and was reported (Lugao et al, 2007;Oliani et al, 2012).…”