Excellent Adhesive Performance for the Thermal Insulation Attribute to Micromorphology Regulation and Controllable Injection of Oxygen-Containing Groups by Low Temperature Plasma Treatment

A low temperature plasma (LTP) surface treatment technology operated under atmospheric conditions with air as the treatment atmosphere is developed for micromorphology regulation and controllable injection of oxygen-containing groups on the surface of ethylene propylene diene methylene (EPDM) thermal insulation to achieve excellent adhesion performance. Optical emission spectroscopy is used to analyze the active species in the LTP. The key treatment parameters are optimized by contact angle measurements, resulting in thermal insulation sample with 3.32 times higher surface energy than the original sample. The surface morphology and composition of the samples are characterized. It is demonstrated that the surface of the thermal insulation shows new structures, thus increasing the surface area of the thermal insulation. In addition, a large number of oxygen-containing groups are introduced to the surface of the thermal insulation, especially -OH, and the O/C increases by 78.57%. Finally, the peel test is performed on the insulation samples with comparison to the grinding samples, which shows that the peel strength of the treated samples increases by 126.92%, while an additional 22% is also obtained compared to the grinding samples. This excellent adhesive performance is mainly caused by the synergistic effect of chemical crosslinking, hydrogen bonding, and mechanical interlocking.