Implications of Interfacial Energetics on the Tack/Debonding of Single and Hybrid Pressure Sensitive Adhesives

Okpe Bernard Okechukwu,Omenyi Sam Nna,Chukwuneke Jeremiah Lekwuwa

doi:10.18535/ijsrm/v9i1.ec01

Abstract

This paper present the implications of interfacial energetics on the tack/debonding of pressure-sensitive adhesives (PSA). The materials used include acrylic, pvc-abro, polyurethane and epoxy by single and hybrid combinations. Mild steel plate of 130mm x 130mm with 1.2mm thickness was used as a substrate. The contact angle was measured on surfaces of PSA and the substrate using OWK and Wu models. The force required to debond the PSA from the substrate (the tack) was measured with a universal testing machine. The results gave the maximum deflections as 4.9074 x10-4 N/mm2 and tack as 3.35769 x10-5 N/m for single PSA of Epoxy are higher than those for Acrylic, Pvc-Abro and Polyurethane PSAs materials. However, with Acrylic/Epoxy and Epoxy/ Pvc Abro hybrids, higher tack forces of 3 x10-5 mJ and 2.725 x 10-5mJ with corresponding higher values of 2.28225 x10-4N/mm2 and 1.61243 x10-4N/mm2 maximum deflections were obtained. These results showed that epoxy is better from tack force. The results clearly show that all the properties – surface free energy, work of adhesion, and tack are higher for hybrid PSA than for the single PSAs ranging from 1.5% to up to 80% difference. It was observed that as the angle of contact increased, the work of adhesion and cohesion increased. The results of this work can find application in dentistry in dentin/adhesive interface and hybridization of dental hard tissues with modified adhesive systems. Applications can also be found in carpentry, in polymer composites for automobile bodies and ceramics.

Highlights

The process of connecting two solids using polymers as adhesives materials shows wide industrial applications
3 Results and Discussion The results of calculated tack force (Ftack), of every single sample which is the force per width of the adhesive layer from the measured area of the plate and the maximum deflection (∂max)⁡N/mm[2] are given in table (1)
With the lower force of 1.11 x10-6 N by Acrylic, the values of maximum and calculated force were least at 1.24793 x10-6 N/m2 and 8.53846 x106 N/m. This suggests that as a tack or deboning forces increase in peeling of pressures sensitive adhesives materials from the substrate, it leads to resultant increment with maximum deflection and calculated tack

Summary

Introduction

The process of connecting two solids using polymers as adhesives materials shows wide industrial applications. Certain viscoelastic properties allow polymers to fulfil the requirement for their classification as adhesives (Creton, 2003; Carelli et al, 2007). For this purpose, the adhesive has to possess a good combination of two characteristic properties: adhesion and cohesion. The adhesive’s stickiness, is distinguished by low viscosity, compulsory for broad contact area and enhanced bond density (Agirre et al, 2009). The adhesives differ by their chemical composition and by the thermomechanical properties of the bonded joints, processing methods, as well as types of reactions during the bonding. An important advantage of the adhesive joint is the uniform distribution of load over a large area avoiding localization of stress (Aubrey & Ginosatis, 1999; Charles, 2003)

Methods

Results

Conclusion