José Antonio Jofre-Reche

Increased adhesion of polydimethylsiloxane (PDMS) to acrylic adhesive tape for medical use by surface treatment with an atmospheric pressure rotating plasma jet

The surface properties of polydimethylsiloxane (PDMS) were modified by treatment with an atmospheric pressure rotating plasma jet (APPJ) and the surface modifications were studied to assess its hydrophilicity and adhesion to acrylic adhesive tape intended for medical applications. Furthermore, the extent of hydrophobic recovery under different storage conditions was studied. The surface treatment of PDMS with the APPJ under optimal conditions noticeably increased the oxygen content and most of the surface silicon species were fully oxidized. A brittle silica-like layer on the outermost surface was created showing changes in topography due to the formation of grooves and cracks. A huge improvement in T-peel and the shear adhesive strength of the APPJ-treated PDMS surface/acrylic tape joints was obtained. On the other hand, the hydrophilicity of the PDMS surface increased noticeably after the APPJ treatment, but 24 h after treatment almost 80% hydrophobicity was recovered and the adhesive strength was markedly reduced with time after the APPJ treatment. However, the application of an acrylic adhesive layer on the just-APPJ-treated PDMS surface retained the adhesive strength, limiting the extent of hydrophobic recovery.

Influence of post-curing temperature on the structure, properties, and adhesion of vinyl ester adhesive

Vinyl ester (VE) resins are widely used as thermoset adhesives in structural joints and composites, but complete curing under environmental conditions is not produced. The existing literature dealing with the effect of post-curing on the structure, viscoelastic, mechanical, and adhesion properties of VE resin is scarce. Therefore, in this study, VE resin was subjected to different post-curing temperatures (50–140 °C) for one hour, and the changes in structure and properties were assessed. The degree of cross-linking of the VE resin depended on the post-curing temperature and cure started to be completed above 100 °C, a temperature close to the glass transition temperature (115 °C) of the completely cross-linked polymer. Furthermore, gel formation in VE resin was evidenced for post-curing temperature below 100 °C. In order to fully cross-link the VE resin, post-curing at 140 °C for one hour was necessary, and it was evidenced by an increase in the glass transition temperature and in the mechanical properties; an increase in adhesion to cold rolled steel was obtained although the shear strength was lower than in the joint produced with the non-post-cured VE resin.

Improvement in Adhesion, Abrasion Resistance, and Aging of Polyurethane Coatings Prepared with Polycarbonate Diol for Internal Pipelines

AbstractThe paper deals with the improvement of adhesion, abrasion resistance, and aging of polyurethane coatings made with polycarbonate diol (PCD) intended for internal pipelines. The influence o...