Effects Of Magnesium Hydroxide Modified By Imidazolium Ionic Liquids On Properties Of Polyethylene

A kind of novel imidazolium ionic liquid (LQ) surface treatment agent, 1-n- tetradecyl-3-carboxymethyl imidazole chloride ([C₁₄cim]Cl), was synthesized in this work. The results of FT-IR and 1H NMR testing show that the structure of product have the characteristic groups of [C₁₄cim]Cl, and the melting point is 131-132oC. Magnesium hydroxide [Mg(OH)₂] was modified by means of ultrasonic methods using [C₁₄cim]Cl and other ionic liquids, namely [C14mim]BF4, [C14mim]Br and [C18mim]Br as modifier in water. It is shown that the modified effect is better when ionic liquids were used comparing with that modified by stearic acid (SA-MH), according to the oil absorption value testing and dispersion effect test in xylene. The FT-IR absorption spectra of [C₁₄cim]Cl-MH observations indicated that the [C₁₄cim]Cl interacted with Mg(OH)2 via chemical bonding, and the absorption scheme was also tentatively proposed in our research.The composites of polyethylene and MH modified by LQ were obtained by means of melt blending; including the high density polyethylene and linear low density polyethylene. Properties of the composites including flame retardancy, antistatic property and mechanical properties were studied. In addition, the dispersive property of MH particles in polyethylene was also investigated. Comparison was made with composites of PE with MH treated by stearic acid. The flame retardancy was researched by horizontal burning (HB) and limiting oxygen index (LOI). The horizontal burning (HB) results indicated that the burning rate of LQ-MH in relative low additions was not improved, but the others have got certain improved. The LOI test provided a different conclusion, the flame retardancy of PE/LQ-MH was somewhat increased comparing with unmodified PE/MH. The results of surface resistivity (ρs) and volume resistivity (ρv) tested showed that all the samples of LQ-MH/PE exhibited obvious improvement in antistatic property. The surface resistivity of some samples were even lower than 1×109 ?·m2, and volume resistivity were lower than 1×1010?·cm.The effects of magnesium hydroxide modified by ionic liquids on mechanical properties of polyethylene were also investigated. The result showed that the mechanical properties of the PE/LQ-MH were significantly improved, especially the impact property. When the LQ-MH was in low additions, the blends of HDPE/LQ-MH have a better impact property when compared with unmodified sample. And the LLDPE/LQ-MH was enhanced significantly both in low addition and high addition. The scanning electron microscope (SEM) results of 150phr LLDPE/[C₁₄cim]Cl-MH showed that the composites of LLDPE and MH modified by [C₁₄cim]Cl have a obvious shape of toughness fracture, and the MH particles disperse evenly in LLDPE matrix.