Delamination and Adhesion improvements by acid pretreatements in Talc-reinforced polypropylene

CASTILLO, LUCIANA E; BARBOSA, SILVIA ELENA; CAPIATI, NUMA JOSÉ

Río de Janeiro, Brasil

Conferencia; Fourtht International Conference on Science and Technology of Composite Materials, COMAT 2007; 2007

Universidad federal de Río de Janeiro

With the final objetive of improve the properties of talc reinforced PP, several investigations are performed on talc bulk dispersion and filler-matrix adhesion increase by talc delamination and surface modification respectively. In this work, an acid treatement is performed on talc particles first to melt mixrd with polypropylene. The reaction between the mineral and a organic acid is a esterification one, in which the superfitial hydroxyl groups (-OH) of the talc and the carboxylic group (-COOH) of the organic acid react. Two different talcs were used for the modification: one of them was from Australia, without impurities and with “blocky”morphology, whereas the other was from Argentinia, with a “platy” morphology, and high content of  calcium carbonate (calcite and dolomite), magnesium carbonate (magnesite) and aluminosilicates (chlorites). Two different series of polypropylene-talc composites were made in a laboratory mixer and the talc’s composition ranged between 1 and 40 wt%. The PP and PP-talc composites were characterized by FTIR spectroscopy, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effect of untreated talc and the talc surface modified with acetic acid, how the talc’s genesis affects in the resultant material, as well as the influence of the concentration’s variation on the properties of the composites is discussed.