Polyethylene Film Surface Modification via Benzoic Acid Grafting

Area of Science:

• Polymer Science
• Materials Science
• Surface Chemistry

Background:

• Polyethylene (PE) films are widely used but possess hydrophobic surfaces, limiting their adhesion to polar substances.
• Improving the surface polarity of PE is crucial for applications requiring enhanced surface interactions, such as printing and coating.

Purpose of the Study:

• To develop an effective surface modification method for polyethylene (PE) films.
• To enhance the surface affinity of PE films towards polar substances through alkylation grafting.
• To assess the feasibility of using modified PE films for applications like packaging and printing with water-based inks.

Main Methods:

• Surface modification of PE films using sequential spraying of aluminum chloride (AlCl3) and benzoic acid (BA) onto a heat-softened surface.
• Evaluation of the grafting reaction through comparative chemical, morphological, and thermal analyses.
• Assessment of surface property changes by comparing the watercolor affinity of modified and unmodified PE films.

Main Results:

• Successful alkylation grafting of benzoic acid (BA) onto the PE film surface was confirmed, confined to the surface layer.
• The grafting process formed aluminum benzoate complexes, significantly improving the surface's affinity for polar compounds.
• Modified PE films demonstrated enhanced adhesion to watercolors, indicating a shift from hydrophobic to hydrophilic surface properties.

Conclusions:

• The proposed benzoic acid (BA) alkylation grafting method effectively modifies PE film surfaces, enhancing their polarity.
• The surface modification preserves the bulk properties of the PE film while rendering it suitable for printing with water-based inks.
• This technique offers a viable solution for applications requiring paintable or printable PE surfaces, such as in the packaging industry.