Abstract

The joint of materials employing adhesives has been used for a long time. However, the possibility of generating joints between materials with remarkably dissimilar surface free energies, as in the case of joining metals and polymeric materials (with hydrophobic nature), is the main goal of this work and a novel area of investigation. In this work, a broad range of different compounds to prepare surfaces of Al2024 and polypropylene (PP) has been studied, in order to be joined subsequently by two kinds of adhesives: structural two-component adhesive DP8005 and double-sided adhesive tape RP45 (due to its interest in fast assembling operations). Surface treatments used in this work are based on non-silane compounds, in particular, two agents of maleinization (in solution), a nitrant agent at different concentrations, due to its behaviour depends on if it reacts as strong acid, oxidant agent or nitrant agent, following by a microwave treatment; a phosphating process; a glycidyl methacrylate treatment and, by a way of comparison, a conventional priming agent. The silane treatments are reported in other work (1).

Abstract

In this work, a wide range of different silane based compounds has been studied with the aim of preparing the surfaces of the Al2024 and the polypropylene (PP). Afterwards, these materials have been joined with two kinds of adhesives: two-component structural adhesive DP8005 and double-sided adhesive tape RP45 (due to its interest in fast assembling operations). The compounds used for surface treatments are based on silane agents. Likewise, same authors have presented non-silane based treatments in other work (1). Both works, complement each other and provide the basis for a third one where the experimental design of measuring properties, mechanical properties in particular, is discussed (3).

Abstract

In this work, different type of surface treatments on aluminium films have been performed. The changes that these treatments produce in the nature, composition, functionality, morphology and free surface energy on the aluminium surfaces will be analyzed. First treatment has been performed in two steps, the first one consists on activating the aluminium surface with sodium metoxyde in methanol and the time and treatment conditions on the nature of the formed surface will be studied. The second treatment has been performed in three steps, so between the activation step and the sylanization, an intermediate treatment has been done in order to try to insert a polymer by "in situ" polymerization on the aluminium surface. Those treated aluminium film surfaces have been characterized using infrared spectroscopy by Fourier transform (FTIR), contact angle measurement, surface energy determination and Dynamic Mechanic Thermal Analysis (DMTA).

Abstract

Sisal fibers have taken special focus by material investigators and commercial environment because they are economical, biodegradable and lightweight(1). Composite manufactured using natural fibers can supply properties that can be compared to other composites reinforced with synthetic fibers, as previous studies have shown (2-6). Thus, fibers that come from nature sources, such as wood, nuts fruit, jute, kenaf, hemp, sisal, etc. are being introduced in composite manufacturing (7-9). Sisal fiber has relevant economical and ecological properties (10), but it is a lignocelulosycal fiber with hydrophylic character, so it is difficult its usage with hydrophobic matrix, and it is required to use coupling agents in order to improve its interface adhesion. This work starts with sisal fibers submitted to different types of primary treatments, and for each one of these treatments, sisal fibers are submitted to secondary treatments of maleinization, mercerization, silanization, formation of nascent surface isocyanates, carboxylation and methacrylate treatment. The efficiency of these treatments has been evaluated using morphology characterization techniques by FTIR-ATR, electronic microscopy (SEM). With some of the treated fibers, thermoplastic composites have been prepared and these have been used to prepare standard probes that have been thermally and mechanically tested, as well as other additional interesting physicochemical characteristics.