Study On Waterborne Acrylic Functional Pressure Sensitive Adhesive Modified By Nanocomposite

In recent years, with the development of economy and enhancement of environmental protection consciousness, waterborne acrylic pressure sensitive adhesive（PSA） has been developed rapidly because of its versatility, easy preparation, stable performance and low cost raw materials. However, acrylic PSA was mainly used in narrow fields, and high quality PSAs for electronics, aerospace, military and other fields were almost imported. Therefore, it is necessary to study on new high-performance waterborne acrylic PSA for special area.In this work, the nano-Fe₃O₄ modified by γ- methacryloyloxy trimethoxysilane（KH570） was first prepared. And then pure nano-Fe₃O₄ and surface functionalized nano-Fe₃O₄ were both used to react with acrylate monomers through in situ emulsion polymerization, and a kind of magnetic PSA was prepared. The Effect of nano-Fe₃O₄ modified by silane coupling agent were investigated. And influence of pure nano-Fe₃O₄ and surface functionalized nano-Fe₃O₄ on the morphology, thermal stability, mechanical and emulsion properties of acrylic emulsion were studied. In addition, nano-Fe₃O₄ and KH570 were used to modify MWCNTs which have been treated by mixed acid. Then waterborne acrylic magnetic and electrically conductive PSA was synthesized by Fe₃O₄/KH570-MWCNT and acrylic emulsion. Fourier transform infrared spectroscopy, Raman spectroscopy, Transmission electron microscopy, X-ray diffraction spectroscopy were used to analyze the effects of nano-Fe₃O₄ and KH570 on the modification of MWCNT. And the integrated properties of modified PSA were characterized by Thermal gravimetric analysis, Differential scanning calorimetry, Vibrating sample magnetometer and Digital multimeter. Meanwhile, the effect of nanoparticles content on the wettability and adhesive properties of acrylic PSA was studied, and the bonding mechanism between modified PSA and stainless steel was also discussed.The experimental results showed that nano-Fe₃O₄ was successfully modified. The heat resistance and thermal stability of PSA were obviously improved by nano-Fe₃O₄ particles, especially for functionalized Fe₃O₄ particles. However, the magnetic properties of functionalized Fe₃O₄ was not as good as pure nano-Fe₃O₄. With the increasing of the nanoparticles content, the magnetic properties of modified PSA are better, while the emulsion properties change a little. MWCNT grafted KH570 and nano-Fe₃O₄ were well compatible with the polymer, the heat resistance, thermal stability, magnetic and electrically conductive properties of the acrylic PSA were improved with the increase of nanoparticles content.It was found that Fe₃O₄/KH570-MWCNT improved the wettability of the acrylic PSA on stainless steel substrate, and adhesive properties were best when the content of Fe₃O₄/KH570-MWCNT was 3vol%, and the tack was No.19, 180 °peeling strength was 12N/25 mm, while holding power reached 139 h. Moreover, the adhesion mechanism of modified acrylic PSA was explored, and this will offer theoretical guidance in PSA.