Effect of pre‐irradiation on radiation stability of co‐polypropylene

Abstract

The radiation stability of the pre-irradiated copolymer of polypropylene containing 2.5 wt.-To ethylene units is compared with a copolymer of polypropylene with a nucleating agent with regard to radiation sterilization of medical devices. It is found that transparency property of the propylene-ethylene copolymer is improved through pre-irradiation processes. This finding was compared with the co-polypropylene with nucleating agent which also gives a better transparency property. In comparison, it is found that pre-irradiated copolymer exhibits better radiation stability during irradiation and during storage after irradiation. The radiation stability of the pre-irradiated copolymer is due to its lower crystallinity caused by the formation of branches during the pre-irradiation process. ZUSAMMENFASSUNG:Die Strahlungsbestandigkeit von vorbestrahltem Polypropylen mit 2,5 Gew.-To Ethylenanteil wurde mitr einem Copolymeren aus Polypropylen und einem nukleierenden Agens im Hinblick auf die Strahlungssterilisation von medizinischen Geraten verglichen. Die Transparenz des Propylen-Ethylen-Copolymeren wurde durch die Vorbehandlung verbessert. Im Vergleich mit der ebenfalls verbesserten Transparenz des Copolymeren aus Polypropylen und dem nukleierenden Agens wurde durch die Vorbestrahlung die Strahlungsbestandigkeit wahrend der Bestrahlung und bei der Lagerung des bestrahlten Materials verbessert. Dies wird auf die geringere Kristallinitat des vorbestrahlten Polypropylens aufgrund von bei der Bestrahlung gebildeten Verzweigungen zuriickgefiihrt.

The Effect of Disinfection Methods on the Mechanical Properties of Thermoplastic Recyclates

“…These tests allow the measurement of parameters sensitive to changes in the molecular structure or morphology. [3][4][5][6][11][12][13][14][15][16][17][18][19][20][21][22][23]25,26] Examination Methods…”

“…[11][12][13][14][15] The impact strength of PP irradiated in air also decreases and the shear modulus may show a drop due to the building of branches. [16][17][18] PE undergoes predominantly cross-linking. This leads to an increase of the average molecular weight and the degree of branching.…”