Effect of hindered amine light stabilizers on the resistance of polypropylene towards ionizing radiation

• Autorzy: Przybytniak G. , Mirkowski K. , Rafalski A. , Nowicki A. , Legocka I. , Zimek Z.
• Języki publikacji: EN

Abstrakty

EN

The influence of hindered amine light stabilizers (HALSs) on physical and mechanical properties of irradiated and non-irradiated isotactic polypropylene (PP) was studied. The stabilizers under investigation were: Tinuvin 765 (T765) and Tinuvin 622 (T622) - derivatives of 1,2,2,6,6-pentamethyl piperidine and Chimassorb 944 (C944) - a derivative of 2,2,6,6-tetramethyl piperidine. It was found that the stabilizers reduce the amount of peroxyl radicals in the amorphous phase of PP. The irradiation with electron beam causes a drop of apparent viscosity both in the original and in the modified PP however the effect is smaller in the presence of HALSs. Admixture of T622 and T765 stabilizers increases the crystallization temperature of non-irradiated PP by about 8 10°C (measured by DSC) what results from the facilitated formation of a large number small microcrystals. It was concluded that HALSs initiate two opposite tendencies - chemical protection against damage initiated by free radicals and, simultaneously, physical enhancement of sensitivity towards irradiation by the increase of nucleation density. In the studied systems, the presence of maleic anhydride does not improve compatibility between the polymeric matrix and HALSs.

Słowa kluczowe

EN

polypropylene; stabilizers; HALS; electron beam; apparent viscosity; nucleation agent

• Wydawca: Institute of Nuclear Chemistry and Technology
• Czasopismo: Nukleonika
• Rocznik: 2005
• Tom: Vol. 50, nr 4
• Strony: 153--159
• Opis fizyczny: Bibliogr. 15 poz., rys.

Twórcy

autor

Przybytniak G.

• Institute of Nuclear Chemistry and Technology, 16 Dorodna Str., 03-195 Warsaw, Poland, Tel.: [phone], Fax: [phone]

autor

Mirkowski K.

• Institute of Nuclear Chemistry and Technology, 16 Dorodna Str., 03-195 Warsaw, Poland, Tel.: [phone], Fax: [phone]

autor

Rafalski A.

• Institute of Nuclear Chemistry and Technology, 16 Dorodna Str., 03-195 Warsaw, Poland, Tel.: [phone], Fax: [phone]

autor

Nowicki A.

• Institute of Nuclear Chemistry and Technology, 16 Dorodna Str., 03-195 Warsaw, Poland, Tel.: [phone], Fax: [phone]

autor

Legocka I.

• Industrial Chemistry Research Institute, 8 Rydygiera Str., 01-793 Warsaw, Poland

autor

Zimek Z.

• Institute of Nuclear Chemistry and Technology, 16 Dorodna Str., 03-195 Warsaw, Poland, Tel.: [phone], Fax: [phone]

Bibliografia

• 1. Ahmed S, Basfar AA (1999) Influence of benzoic acid on thermal, crystallisation and mechanical properties of isotactic polypropylene under irradiation. Nucl Instrum Meth Phys Res B 151:169−173.
• 2. Allen NS, McKellar JF (1978) Photostabilization of commercial polypropylene by a Hindered Amine Stabilizer.J Appl Polym Sci 22:3277−3282.
• 3. Bauer DR, Gerlock JL (1986) Photo-stabilisation and photo-degradation of organic coatings containing a hindered amine light stabiliser: Part III −Kinetics of stabilisation during free radical oxidation. Polym Degrad Stab 14:97−112.
• 4. Carlsson DJ, Can Z, Wiles DM (1987) Polypropylene photostabilization by hindered amines in the presence of acidic species. J Appl Polym Sci 33:875−884.
• 5. Cho K, Li F, Choi J (1999) Crystallization and melting behaviour of polypropylene and maleated polypropylene blends. Polymer 40:1719−1729.
• 6. Dweik H, Al-Jabareen A, Marom G, Assouline E (2003) Thermal and chemical effects of nucleating agents on α, β, γ-polymorphism of isotactic polypropylene. Int J Polym Mat 52:655−672.
• 7. Gadzinowska K, Piorkowska E (2003) Influence of sample thickness and surface nucleation on i-PP crystallization kinetics in DSC measurements. Polimery 48:790−799 (inPolish).
• 8. Gensler R, Plummer CJG, Kausch HH, Kramer E, Pauquet JR, Zweifel H (2000) Thermo-oxidative degradation of isotactic polypropylene at high tempera-tures: phenolic antioxidants versus HAS. Polym DegradStab 67:195−208.
• 9. Kashiwabara H, Shimada S, Hori Y (1991) Nature of peroxy radicals in polypropylene. Radiat Phys Chem 37:511−515.
• 10. Nagasawa S, Fujimori A, Masuko T, Iguchi M (2005) Crystallisation of polypropylene containing nucleators. Polymer 46:5241−5250.
• 11. Romankiewicz A, Sterzynski T, Brostow W (2004) Structural characterization of α- and β-nucleated isotactic polypropylene. Polym Int 53:2086−2091.
• 12. Sterzynski T (2004) Structure modification of isotactic polypropylene by bi-component nucleating systems. Polym Eng Sci 44:352−361.
• 13. Sun GJ, Jang HJ, Kaang S, Chae KH (2002) A new polymeric HALS: preparation of an addition polymer of DGEBA-HALS and its photostabilizing effect. Polymer 43:5855−5863.
• 14. Triacca VJ, Gloor PE, Zhu S, Hrymak AN, Hamielec AE (1993) Free radical degradation of polypropylene: random chain scission. Polym Eng Sci 33:445−454.
• 15. Wang H, Chen W (1998) Effect of penta- and tetramethyl HALS on the radiation resistance of polypropylene. J Appl Polym Sci 69:2649−2656.