Sains Malaysiana 40(7)(2011): 803–808

Effect of Pro-Degradant Additive on Photo-Oxidative Aging of

Polypropylene Film

(Pengaruh Aditif Pro-degradasi pada Penuaan Foto-Oksidatif Filem Polipropilina)

Noor Zalikha Mohamed Islam, Nadras Othman*, Zulkifli Ahmad & Hanafi Ismail

School of Materials and Mineral Resources Engineering, USM Engineering Campus

Universiti Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia

Received: 23 October 2009 / Accepted: 20 September 2010

ABSTRACT

This paper describes the effect of pro-degradant additives (PDA) on photo-oxidative aging of polypropylene (PP) films after being time accelerated in UV-weathering chamber. Thin films (0.12 mm) containing these additives were prepared by sheeting process. The effect of UV on PP films in the presence of these additives was investigated. Changes in the PP films appearance, tensile properties and carbonyl index (CI) were used to investigate the degradation behavior. The films became completely pulverised after 100 h of photo-oxidative treatment and could not be tested further. Films containing PDA showed rapid loss in tensile properties within 100 h of photo-oxidative aging. In addition, the CI results of photo-oxidative films increased with increasing PDA amount within the time interval of aging and the activity was due to the mechanism reaction of PP with PDA particles. During the aging process the material becomes denser due to tighter packing and incorporation of oxygen into the amorphous regions of the polymer. The results indicated that the presence of PDA contributed to the photo degradation and the activity was very much influenced by the amount PDA.

Keywords: Degradable polypropylene; photo-oxidative aging; pro-degradant additives

ABSTRAK

Makalah ini menghuraikan tentang pengaruh aditif pro-degradasi (PDA) terhadap penuaan filem foto-oksidatif polipropilina (PP) selepas dipercepat penuaannya dalam kebuk cuaca-UV. Filem nipis (0.12 mm) yang mengandungi aditif ini disediakan melalui proses penipisan helaian. Pengaruh UV pada filem polipropilina dengan kehadiran aditif tersebut telah diselidiki. Perubahan terhadap rupa polipropolina filem, sifat-sifat terikan dan indeks karbonil (CI) telah digunakan untuk mengkaji perilaku degradasi. Filem-filem ini menjadi serbuk secara keseluruhan selepas 100 jam perawatan foto-oksidatif dan tidak boleh diuji dengan lebih lanjut lagi. Filem yang mengandungi PDA telah menunjukkan kemerosotan ketara dalam 100 jam penuaan foto-oksidatif. Selain daripada itu, keputusan CI filem foto-oksidatif telah meningkat dengan bertambahnya jumlah PDA dalam tempoh waktu penuaan dan aktiviti itu berlaku kerana reaksi mekanisme PP dengan partikel PDA. Semasa proses penuaan, bahan menjadi lebih tumpat kerana pembungkusan lebih ketat dan gandingan oksigen ke dalam kawasan amorfus polimer. Keputusan kajian menunjukkan bahawa PDA menyumbang kepada degradasi foto-oksidatif dan aktiviti sangat dipengaruhi oleh jumlah PDA.

Kata kunci: Aditif pro-degradasi; penuaan foto-oksidatif ; polipropilina terdegradasi

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*Corresponding author; email: srnadras@eng.usm.my