Atmospheric pressure plasma application on the adhesive bonding improvement of CFRP via surface configuration comparison

Carbon fiber reinforced polymer (CFRP) has a wide range of applications in aerospace, automobile, marine, and other industries, due to its remarkable mechanical properties and lightweight. It can enhance the performance of the structural components and has been presented to be a good alternative over conventional materials. Adhesive bonding has been widely employed, and research studies on the surface modification of CFRP have been conducted to improve the load resistance of adhesive bonding, of which atmospheric pressure (AP) plasma is the most preferred method. However, there is still a lack of study on the effectiveness and strategies of AP plasma surface modification. To gain more insight, possible sources that would have influence on the adhesive bonding were analyzed by preparation of different surface configurations of CFRP. It is confirmed that AP plasma can increase the surface polarity and wettability of the carbon fiber surface. It can contribute to the removal of surface contamination element as well. Although the surface morphology and surface roughness before and after the AP plasma treatment does not show noticeable changes, the single-lap shear strength of the contaminated samples can be effectively improved. This study validates that AP plasma is effective on surface contamination removal and bonding quality improvement, which provides a potential alternative for the adhesive bonding improvement and surface modification of carbon fiber. Highlights: Surface polarity and wettability increase of CFRP by AP plasma. Surface contamination removal and bonding quality improvement by AP plasma. AP plasma provides a potential alternative method for adhesive bonding pre-treatment. AP plasma surface modification mechanism analysis via surface characterization.