The effect of acidity behaviour of Y zeolites on the catalytic degradation of polyethylene

• Published in: European polymer journal 2006-07, Vol.42 (7), p.1541-1547
• Main Authors: Neves, Isabel C., Botelho, Gabriela, Machado, Ana V., Rebelo, Patrícia
• Format: Article
• Language: English
• Subjects: Applied sciences; Catalytic cracking; Deactivation; Exact sciences and technology; Ion exchange; Polymer degradation; Polymer industry, paints, wood; Technology of polymers; Waste treatment; Y Zeolite
• ISSN: 0014-3057; 1873-1945
• DOI: 10.1016/j.eurpolymj.2006.01.021

Thermogravimetric (TGA) and differential scanning calorimetric (DSC) analyses were used to investigate the effect of the acidity behaviour of Y zeolites on the catalytic degradation of polyethylene (PE). The acidity behaviour of these zeolites was modified by ion exchange treatments. Two Y zeolites with similar Si/Al atomic ratios were subjected to an ion exchange treatment using NaNO 3 for H-form (HY) and NH 4NO 3 for Na-form (NaY). The activity and the deactivation behaviour of the Y zeolites were determined in the samples by TGA measurements, using a polymer/catalyst ratio of 9:1. The sample residues obtained after an isothermic TGA, were analysed by DSC, in order to evaluate the crystallinity of each mixture. The HY zeolite, which has the strongest acidity, reduced the onset temperature resulting in more rapid degradation of the polymer. It is shown that the ion exchange treatment over Y zeolites enhances the selective catalytic degradation of polymer in detriment of the rapid deactivation.