The Preparation, Structure And Performance Of Nylon / Montmorillonite Nanocomposites

Montmorillonts(MMT) were modified by several different intercalation agents and its process of preparation was studied; The melt casting nylon (MC-nylon) /MMT nanocomposites and the nylon66 /MMT nanocomposites were prepared respectively by in situ polymerization and melt intercalation using the clay modified by cetyl trimethyl ammonium bromide(CTAB) and coupling agents KH-550 as the filler. The conclusion was as follows:1. Modification of MMT's galleries(1) The process of MMT modified by CTAB was studied through viscosimetric analysis: the additon of CTAB was 105mmol/100g clay. Reaction temperature was 70 and reaction time was 2h. Xray diffraction (XRD) showed that CTAB had entered into the galleries of MMT and make the d-spacing of MMT increased from 1.18nm to 3.0nm . Fourier transform IR spectroscopy (FTIR) showed that MMT was absorbed by CTAB and its hydrophylic property was weeken significantly.The process of MMT modified by coupling agent KH-550 was studied : the addition of KH-550 was 2% in water solution and reaction time was 1.5h. XRD showed that the d-spacing of MMT was increased from 1.18nm to 1.9nm .FTIR showed that there was a reaction between KH-550 and the surface of MMT.(2) A new kind of organophilic montmorillonite was prepared successfully by simple intercalation of a new kind of cationic gemini surfactant. The mechanism of the intercalation is also studied. XRD showed that when the number of caborn chain is 12, d-spacing was increased form 1.18nm to 3.8nm. When the number is 16, d-spacing was 4.2nm. The mechanism of the intercalation is also studied. The UV-spectrum and Sedimentation experiment had shown that the MMT modified by Gemini Ci2 has the good compatibility and dispersibility than the conventional surfactants in oil solution.2. MC-nylon /MMT nanocomposites prepared through in situ polymerization XRD showed that the d-spacing was enlarged by the MC-nylon. The spherulitesof MC-nylon was changed by MMT. When the containing of the clay was 2%, the ratio of o/y in MC-nylon was highest. The ratio of o/y becomes smaller and smaller with the containing increasing. Molue experiments and FTIR showed that nylon chain had entered into the galleries.3. nylon66 /MMT nanocomposites prepared through melt intercalationThe results of mechanical tests showed that the tensile strength and notch impact strength of nylon66 were increased by 15% and 5% respectively, when the containing of clay was 2%-4%. TG shows that the thermolysis temperature of the composites is improved. XRD showed that (1) he d-spacing had been enlarged by the nylon 66 and (2) The spherulites of nylon 66 was changed by MMT. The containing of Spherulites y was enhanced with the containing of MMT increasing.