Which materials can be bonded with adhesives?

Materials Bondable by Adhesives
1. Metals
Metal surfaces bond well after surface treatment to remove oxide layers; however, significant differences in the coefficients of linear thermal expansion between the metal and the adhesive can lead to internal stress within the bond line. Additionally, bonded metal joints are susceptible to electrochemical corrosion caused by moisture.
2. Rubber
The higher the polarity of the rubber, the better the bonding performance. Nitrile and chloroprene rubbers, for instance, possess high polarity and yield strong bonds, whereas natural rubber, silicone rubber, and isobutylene rubber have low polarity and weaker adhesion. Furthermore, the presence of mold release agents or other migrating additives on the rubber surface can impair bonding effectiveness.
3. Wood
Wood is a porous material that readily absorbs moisture, leading to dimensional changes and potential stress concentrations. Additionally, polished wood surfaces generally offer better bonding performance than rough ones.
4. Plastics
Plastics with high polarity exhibit good bonding performance.

5. Glass
At a microscopic level, the surface of glass consists of countless uneven irregularities. Using an adhesive with good wetting properties helps prevent air bubbles trapped in these irregularities from compromising the bond. Additionally, glass features a primary Si-O structural backbone, making its surface prone to moisture adsorption. Due to the high polarity of glass, polar adhesives readily form hydrogen bonds with the surface, resulting in a strong bond. Factors such as the material's transparency and brittleness must also be considered when selecting an adhesive.

Polypropylene (PP) is a non-polar material with low surface energy; consequently, bonding processes involving PP often suffer from poor adhesion between the substrate and the adhesive, leading to issues like bond failure. An effective solution—often recommended by coating specialists—is to subject the PP surface to proper pretreatment. Beyond basic cleaning, applying a PP primer or treatment agent between the substrate and the adhesive enhances adhesion and prevents bond failure.