The Effect of Poly(vinylpyrrolidone) Concentration on Peel Strength of Acrylic/PVP Pressure Sensitive Adhesive Blends

The influence of poly(vinylpyrrolidone) (PVP) concentration on the peel strengthof an acrylic pressure-sensitive adhesive (PSA) has been studied as a functionof the adhesive thickness. Different amounts of PVP (2-30% w/w) were mixedthoroughly with an acrylic PSA. Films with different thicknesses (10, 40, and 70 μm)were prepared by casting the formulation on a poly(ethylene terephtalate) film. Peeltests were carried out by adhesive-coated tapes of 25 mm width on the stainless steelsubstrate at least for three samples.The samples were investigated by Fourier transmittanceinfrared (FTIR) spectroscopy technique and surface tension and viscoelasticproperties measurements. The peel strength values are directly dependent on thethickness of adhesive. Also, results showed that due to the polar part of blend in2 %w/w PVP, the peel strength has the maximum value. At higher concentrations ofPVP, due to its surface migration, reduction in peel strength was more pronounced.The parallel investigations on the viscoelastic properties of blends showed that thestorage modulus shifts to higher values at higher concentrations of PVP. Therefore,the bonding step becomes difficult and the peel strength decreases significantly.