The Study Of Ionomers Based On Maleic Grafted Polyethylene

mPE(maleic anhydride grafted polyethylene) sodium ionomers with different neutralization degrees were prepared by mPE reacted with sodium hydroxide in solution and melt state separately, and mPE zinc ionomers by mPE reacted with zinc hydroxide in melt. Ionic crosslinking was formed after mPE was neutralized both by sodium and zinc cation. FTIR was introduced to characterize the structures of ionomers to analyze differences between the two methods, and ionic crosslinking mechanisms of sodium and zinc ionomers. Melt mass-flow rate (MFR), DSC, WXRD, rotational rheometer, TGA, melt sag, water absorption, and tensile tests were used to study the melt property, crystallization, rheology, thermal stability, physical crosslinking effects, hydroscopic. property, mechanical property of ionomers, and their relations with neutralization degrees and cations.With the increasing of sodium hydroxide or zinc hydroxide added, the neutralization degree increased, but could not reach 100%. With the increasing of neutralization degree, MFR of mPE sodium and zinc ionomers declined, melt strength increased, physical crosslinking enhanced, but mechanical property decreased. FTIR results showed that, ionic crosslinking in sodium ionomers was formed from the aggregations of ion pairs or ion clusters, while in zinc ionomers formed from the coordination of zinc ion and a few ion aggregations. So the effect of physical crosslinking in sodium ionomers was stronger than zinc ionomers, and the influences of sodium on ionomers'propeties were more obvious than zinc. Compared with mPE, Tm of mPE sodium ionomers raised by 1-6℃, Xc decreased by 5%-12%, water absorption increased; Tm of mPE zinc ionomers just raised by 1-2℃, Xc decreased by 1.5-6%, water absorption decreased. The dimension of ion concentration region was larger in zinc ionomers than sodium. Rheological behavior study suggested that the mobility of mPE chain was restricted after neutralization and tanδ<1. Also found that crosslinking induced by chain degradation above 230℃occured both in mPE and ionomers, and the onset tempreture of degradation-crossking of ionomers was higher than mPE. So combined with TGA, it was confirmed that the thermal stability of mPE chain enhanced after neutralization. Additionally, sag resistance method was introduced to analyze the interaction betweeen ionic crosslinking and gravity in this paper.