Effect of the Process Parameters on the Adhesive Strength of Dissimilar Polymers Obtained by Multicomponent Injection...

Area of Science:

• Materials Science
• Polymer Engineering
• Sustainable Materials

Background:

• Growing consumer demand for sustainable products drives innovation in natural fiber composites.
• Understanding adhesive properties of overmolded parts is crucial for new applications.
• Polypropylene (PP) and natural fiber composites offer a sustainable alternative.

Purpose of the Study:

• To evaluate the adhesive strength between polypropylene (PP) and a PP-coconut-fiber composite.
• To analyze the effect of processing conditions on the bond strength of dissimilar materials.
• To determine key factors influencing the interfacial adhesion in overmolded composites.

Main Methods:

• Development of a polypropylene composite with 30% coconut fibers using a twin-screw extruder.
• Creation of a multicomponent injection mold for ISO 527 type I specimens.
• Pure shear analysis using an adhesive strength testing device under statistically designed experimental conditions.

Main Results:

• Adhesive strength significantly increased with a larger overlap area between PP and the PP-coconut-fiber composite.
• Processing temperature and injection flow rate were identified as critical factors positively impacting bond strength.
• The study successfully quantified the interfacial adhesion between the dissimilar materials.

Conclusions:

• Optimizing processing temperature and injection flow rate is key to maximizing the adhesive strength of overmolded PP-coconut fiber composites.
• Increased overlap area is a direct contributor to enhanced bond strength.
• These findings support the use of overmolded natural fiber composites in applications requiring strong interfacial adhesion.