Improvement of autohesive and adhesive properties of polyethylene plates by photografting with glycidyl methacrylate

Abstract

Glycidyl methacrylate (GMA) was photografted with the low-and high-density polyethylene (LDPE and HDPE) plates to provide their surfaces with autohesive and adhesive properties. The chemical composition and wettability of the GMA-grafted LDPE and HDPE (LDPE-g-PGMA and HDPE-g-PGMA) plates remained constant above full coverage of the surfaces with grafted PGMA chains. Autohesive strength obtained with 1,4-dioxane as a good solvent of PGMA increased with an increase in the grafted amount and substrate breaking was observed at the grafted amount of 117 mmol/cm 2 . The grafted amount at substrate breaking was decreased by increasing the temperature and load during heat pressing. Adhesive strength was effectively enhanced by use of multi-functional amine compounds because of the increase in the reaction between primary or secondary amine groups and epoxy groups appended to the grafted PGMA chains. In addition, the decrease in the amine compound concentration and the increase in the number of amino groups in the amine compounds used led to the decrease in the grafted amounts at substrate breaking. Substrate breaking occurred at lower grafted amounts for the HDPE-g-PGMA plates than for the LDPE-g-PGMA plates because the location of the photografting was restricted to the outer surface region for the HDPE plate.

Photografting of Methacrylic Acid onto Plasma-pretreated Poly(tetrafluoroethylene) Plates and Enhancement of Their Adhesivity

“…As the plasma treatment time was shorter and/or the monomer concentration for the photografting was higher, the grafted amount at substrate breaking was lower. The occurrence of substrate breaking supports that the adhesive strength exceeded the ultimate strength of the PTFE plate used [7][8][9]. However, for both the grafted PTFE plates prepared at 1.0 M after the plasma treatment and ones prepared by the plasma treatment for 10 s and subsequent photografting at 1.5 M, no substrate breaking was observed, although both water wettability and adhesive strength increased with the plasma treatment time.…”

“…The plasma-treated PTFE plates were immersed in an acetone solution of BP at 0.5 w/v% for 1 min, and then acetone was evaporated at room temperature to coat their surfaces with BP [7][8][9]. The plasma-treated PTFE plates were vertically placed into aqueous MAA solutions at 1.0-2.0 M in the Pyrex glass tubes and UV rays emitted from a 400 W high-pressure mercury lamp were irradiated at 60°C.…”

“…The contact angles for water on the grafted PTFE surfaces were measured by the sessile drop method at 25°C and the cos  values were obtained from the average values [7][8][9].…”

“…On the other hand, the surface modification by grafted polymer chains can control the time-dependent regression of modified surface properties. However, surface modification of the PTFE plate by grafting is rather difficult mainly due to its high chemical stability, whereas polyethylene (PE) and polypropylene (PP) plates can be readily modified by the photografting technique without any pretreatments [7,8].…”

“…We have also extensively investigated the improvement of adhesivity of the PE and PP plates by the photografting technique [7][8][9]. Wettability is improved by photografting hydrophilic monomers, and the substrate breaking occurred at higher grafted amounts.…”