New chemical treatment of bentonite for the preparation of polypropylene nanocomposites by melt intercalation

• Bentonite chemically modified with alkyl aluminum to prepare nanocomposites of PP
• Modified bentonites incorporated in polypropylene with coupling agent in melt
• PP/nanoclay showed increase in d-spacing and higher properties.
• The treated clay has increased degradation temperature and mechanical parameters.
• It was found that treatment with triethylaluminum was more efficient.

In the present work, sodium bentonite was chemically modified with alkyl aluminum compounds to prepare polypropylene nanocomposites containing nanosized clay with homogeneous morphology. The compounds were compared with PP/commercial organoclay containing alkyl ammonium ions. Both unmodified and modified bentonite compounds were incorporated in a commercial PP matrix and maleated PP (PP-MA) as coupling agent was also mixed by melt intercalation using a mini-extruder. The obtained clay/polymer nanocomposites (CPN) were characterized by differential scanning calorimetry, X-ray diffractometry, thermodynamic–mechanical analysis and thermogravimetry. According to the results of the method developed in this study, the prepared PP-nanocomposites containing clays with different chemical treatments exhibited an increase of the d-value of the clay in the XRD, and resulted in much better properties, like increased degradation temperature and mechanical parameters, compared with those of the polymer without clay and of the materials with untreated clay. Also, treatment with triethylaluminum was most efficient.