Enhancement of Adhesion Characteristics of Low-Density Polyethylene Using Atmospheric Plasma Initiated-Grafting of Polyethylene Glycol

Abstract

The low-density polyethylene/aluminum (LDPE/Al) joint in Tetra Pak provides stability and strength to food packaging, ensures protection against outside moisture, and maintains the nutritional values and flavors of food without the need for additives in the food products. However, a poor adhesion of LDPE to Al, due to its non-polar surface, is a limiting factor and extra polymeric interlayers or surface treatment is required. Plasma-assisted grafting of the LDPE surface with different molecular weight compounds of polyethylene glycol (PEG) was used to improve LDPE/Al adhesion. It was found that this surface modification contributed to significantly improve the wettability of the LDPE surface, as was confirmed by contact angle measurements. The chemical composition changes after plasma treatment and modification process were observed by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). A surface morphology was analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Adhesion characteristics of LDPE/Al adhesive joints were analyzed by the peel tests. The most significant adhesion improvement of the PEG modified LDPE surface was achieved using 10.0 wt.% aqueous (6000 M) PEG solution, while the peel resistance increased by approximately 54 times in comparison with untreated LDPE.

Atmospheric plasma treatment effect on shear strength of GFRP-Aluminum adhesively bonded lap joints

“…The active functional groups contribute hydrogen bonding with the adhesive, resulting in a strong adhesive force when compared to the Van der Waals force [33]. There is also good agreement with the results of water contact angle measurements, which show that wetting increases because of the increase in oxygen-related functional groups [32]. Surface adhesion may have improved, and bond strength increased due to the enhanced surface wettability of GFRP substrates resulting from the reduction in contact angle after plasma treatment.…”

“…It is thought that the cleaning of the surface and the formation of hydrophilic polar groups on the surface with the effect of plasma treatment are the main reasons for the decrease in the contact angle [31]. Plasma treatment causes surface oxidation and the introduction of new polar functional groups into polymer surfaces, such as C=O, -OH, COOH, and C-O-C, which increases wettability [32].…”

Bacterial Biofilm Formation on Biomaterials and Approaches to Its Treatment and Prevention

“…The physicochemical properties of the material surface of implants affect the adhesion behavior of cells on the material surface and the subsequent biofilm formation process [164]. These characteristics include electrostatic interactions and van der Waals forces between the material surface and cells; the surface energy and hydrophobicity of the material; the morphological characteristics of the material surface, such as roughness, surface composition, and topography; and functional chemical group modifications of the material surface [165]. Surface modification of biomaterials is a potential strategy to prevent bacteria from attaching and forming biofilms on the surface of materials [166].…”

Significantly Enhanced Conformal Contact by the Functional Layers on a Copper Film for Thermal Interface Materials

“…[27,28] The differential scanning calorimetry (DSC) analysis of pure PEG clearly shows an endothermic melting peak at 52.7 °C (Figure 2c). [29] The solid-liquid phase change with this low melting temperature is advantageous to fill the gap between mating surfaces and realize conformal contact during the electronic device operation. This can decrease R c dramatically as soon to be demonstrated.…”