(181al) Characterization and Evaluation of PMMA Interfacial Cohesion Under Various Bonding Conditions

Bonding of various classes of polymeric materials is of interest for fabricating novel microfluidic systems. By applying heat and pressure to thermoplastic materials, the overlap of two pieces can be bonded and form a hermetic system. In this work, experimental results of cohesion behavior of PMMA sheets are collected and presented. The samples were prepared and bonded by subjecting a sample (two PMMA sheets with an overlapping area and two free ends) to its glass transition range (85 to 165°C) and elevated pressure. Five different bonding temperatures (140 to 180°C, increase at 10°C increments) and three bonding pressures (1.17 MPa, 1.38 MPa, and 1.59 MPa) were applied for making samples. Afterward, mechanical strength tests (T-peel test and lap-shear test) and Scanning Electron Microscope (SEM) analysis were carried out to evaluate the cohesion behavior (bonding strength and shear strength, respectively) and surface morphology of the overlap areas’ surface after peeling off the other layer. The results show that under the same fabrication pressure, the forces needed to separate the overlap area of PMMA layers are greater when the fabrication temperature is higher.