1 research outputs found
Unprecedented Adhesive Performance of Propylene-Based Hydroxyl-Functionalized Terpolymers
The synthesis of hydroxyl-functionalized propylene-based
terpolymers
and their performance as hot melt adhesives were investigated. The
products comprise uniformly distributed butyl and 4-hydroxyl-butyl
branches along the polypropylene backbone. Despite the low hydroxyl-functionality
level of ≤ 0.5 mol %, hydroxyl-functionalized terpolymers show
formidable adhesion to aluminum and steel, providing an adhesive strength
exceeding 16 MPa, whereas the nonfunctionalized congeners hardly adhere
to these metals. As evidenced by rheological measurements, the functional
groups form dynamic crosslinks based on hydrogen bonding and electrostatic
interactions with aluminum oxide hydroxide residues, remaining in
the product after polymerization. At the industrial application temperature
of 180 °C, nondeashed and deashed samples of polymers having
0.1 or 0.5 mol % incorporated 5-hexen-1-ol gave, upon cooling to room
temperature, comparable adhesive strengths. Deashing and increasing
the functionality level lead to a significant improvement of the adhesion
strength at a lower application temperature (130 °C), allowing
application of the hydroxyl-functionalized propylene-based terpolymers
as high-strength hot melt adhesives for combinations of polypropylene
and metals