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 strength of an acrylic pressure-sensitive adhesive (PSA) has been studied as a function of the adhesive thickness. Different amounts of PVP (2-30% w/w) were mixed thoroughly with an acrylic PSA. Films with different thicknesses (10, 40, and 70 11m) were prepared by casting the formulation on a poly(ethylene terephtalate) film. Peel tests were carried out by adhesive-coated tapes of 25 mm width on the stainless steel substrate at least for three samples. The samples were investigated by Fourier transmittance infrared (FTIR) spectroscopy technique and surface tension and viscoelastic properties measurements. The peel strength values are directly dependent on the thickness of adhesive. Also, results showed that due to the polar part of blend in 2 %w/w PVP, the peel strength has the maximum value. At higher concentrations of PVP, due to its surface migration, reduction in peel strength was more pronounced. The parallel investigations on the viscoelastic properties of blends showed that the storage modulus shifts to higher values at higher concentrations of PVP. Therefore, the bonding step becomes difficult and the peel strength decreases significantly.