Effects of Preparation Methods of Organoclays with Polyvinyl Alcohol in their Compatibility with HDPE. Thermal Stability

María C. Carrera^a*, Eleonora Erdmann^b and Hugo A. Destéfanis^a

^a Instituto de Investigaciones para la Industria Química - INIQUI-CONICET,

Consejo de Investigaciones- CIUNSa, Facultad de Ingeniería- UNSa, Av. Bolivia 5150- 4400, Salta, Argentina.

^b Instituto Tecnológico de Buenos Aires-ITBA, Instituto de Investigaciones para la Industria Química INIQUI (UNSa-CONICET). Av. Eduardo Madero 399, C1106ACD, Buenos Aires, Argentina.

Corresponding author Email : celestecarrera@gmail.com  Fax: +54-387-4251006

Accepted 01 September 2013

Abstract

In this paper, the effect of polyvinyl alcohol addition on organoclay obtained by in situ polymerization and subsequent alcoholysis of polyvinyl acetate is studied. The incorporation of the monomer is carried out following two procedures. The first is the incorporation of the monomer by direct contact between the monomer and the organoclay.  The second procedure involves a first step of impregnating the organoclay with propyl alcohol and the subsequent incorporation of the monomer. Both procedures consist of the polymerization in situ via a free radical mechanism. PVA modified clays showed substantial improvements in thermal properties with respect to the organoclay (MMT_HDTMA), corresponding to the greater stability to clay obtained by direct contact with the monomer, PVA_MMT/HDTMA (VA).  The clays prepared by both methods were incorporated into a HDPE matrix by melt blending, to study the effect of the method of preparing the organoclay with PVA in the polymer/clay compatibility  and the effect on their thermal properties. The material characterization techniques were performed using X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermal analysis (TG, DTG, DSC) and transmission electron microscopy (TEM). The results show a clear improvement in the HDPE thermal properties with the addition of organoclays containing PVA and allow a discussion of effect of preparation on compatibility and improved thermal properties.

Keywords: polyvinyl alcohol, montmorillonite, organoclay, HDPE, nanocomposites.