Urška Šebenik

IR Drying of Water-Based Acrylic PSA Adhesives

Results of infrared drying of an acrylic microsphere adhesive coating are presented. The effect of IR drying on adhesive coating was analyzed by Fourier transform infrared spectroscopy (FTIR). The adhesion strength was tested by peel adhesion measurement. Drying was experimentally carried out on materials dried to the same moisture extent at different operating conditions. The power of IR heating source, time of drying, and distance between adhesive coating and heating source were varied. The developed phenomenological model was compared with existing empirical models.

Chapter 5:Acrylic–Clay Nanocomposites by Suspension and Emulsion Polymerization

This chapter is focused on the synthesis and properties of acrylic/clay nanocomposite pressure-sensitive adhesives (PSA), which are an example of use of low glass transition temperature acrylic/clay nanocomposite materials. These acrylic/clay nanocomposites can be synthesized in situ, by carrying out an emulsion or suspension (co)polymerization of a chosen monomer or monomers in the presence of clay. The properties of a PSA depend upon balance of three basic adhesive properties: tack, peel strength, and shear resistance. Hence, to be an effective PSA, the material needs a balance of elasticity and viscosity. Here it is shown how the incorporation of nanosized clay into PSA latex film offers an effective means to modify the viscoelastic properties of PSA, with the aim of optimizing the adhesive properties. The adhesive properties are changed according to the specific end use of the adhesive and can be adjusted by choosing an appropriate nanocomposite synthesis method and by using the proper type and amount of clay.

Modification of NR/BR blend with unsaturated thermo plastic polyurethane; polyurethane synthesis, blend morphology, vulcanization, and vulcanizate properties

Abstract The unsaturated polyurethane (PU) was synthesized, characterized, and used in rubber compound. To study the effect of PU incorporation in the blend a systematic approach was used where PU was added to the natural rubber (NR), butadiene rubber (BR), and NR/BR blends. Different un-vulcanized and vulcanized compounds were characterized and the vulcanization process was investigated. It was observed that the synthesized PU was able to crosslink with the rubber compounds during the vulcanization process. The lowered temperature of melting indicated a better processability of the composites containing thermoplastic PU which melted at processing temperature, thereby allowing improvement in blend viscosity mold flow and to some extent in its homogeneity, although the mechanical properties such as hardness, tensile strength, modulus, and elongation at break did not differ significantly from the properties of elastomer blends without PU. The thermal stability of compounds with PU did not significantly worsen.