Neodymium oxide co-catalyzed melt free radical grafting of maleic anhydride onto co-polypropylene by reactive extrusion

• Published in: Reactive & functional polymers 2006-09, Vol.66 (9), p.984-992
• Main Authors: Zhu, Lianchao, Tang, Gongben, Shi, Qiang, Cai, Chuanlun, Yin, Jinghua
• Format: Article
• Language: English
• Subjects: Applied sciences; Chemical modifications; Chemical reactions and properties; Co-polypropylene; Exact sciences and technology; Graft copolymers; Organic polymers; Physicochemistry of polymers; Rare earth oxide; Reactive extrusion; Synergistic effect
• ISSN: 1381-5148
• DOI: 10.1016/j.reactfunctpolym.2006.01.007

Rare earth oxide, neodymium oxide (Nd 2O 3), co-catalyzed melt grafting of maleic anhydride (MAH) onto co-polypropylene (co-PP) in the presence of dicumyl peroxide (DCP) was carried out by reactive extrusion. The experimental results reveal that the addition of Nd 2O 3 as a coagent leads to an enhancement in both MFR and the grafting degree of MAH, along with a simultaneous decrease in the gel content. When the Nd 2O 3 concentration is 6.0 mmol%, the increment of the grafting degree of MAH maximally is up to about 20% compared with the related system without adding Nd 2O 3, and the gel content decreases simultaneously to a very low level of about 3%. Attenuated total reflection FTIR (ATR-FTIR) indicates that the gel in the graft copolymers mainly arise from the cross-linking reaction between ethylene units of co-PP. A reasonable reaction mechanism has been put forward on the basis of our experimental results and other mechanisms reported in the literature. We also tentatively explain above results by means of synergistic effect between DCP and Nd 2O 3, which causes a higher concentration of the macroradical, in particular the tertiary macroradical.