Modification of LDPE molecular structure by gamma irradiation for bioapplications

Abstract

The surface properties of low-density polyethylene (LDPE) can be modified by the grafting of 2-hydroxyethyl methacrylate (HEMA). This was done aiming at the production of new materials suitable for bioapplications. Samples with different monomer concentrations were prepared from LDPE particles by gamma irradiation, following different irradiation protocols, including irradiation in presence and absence of air. The samples were characterized by thermal analysis techniques (DSC and TGA) and by Fourier transform infrared spectroscopy (FTIR). The results obtained show a decrease in the crystallinity of the supporting matrix for copolymers with high yields of grafting. However, the new materials prepared maintain good structural order resulting from the protective effect of polyHEMA grafted onto LDPE backbone. These effects can improve the diffusion of other species deeper inside the matrix and increase the material hydrophilicity. The studies performed made possible the selection of experimental protocols adequate for the production of new copolymeric materials with high grafting yield. These were used in the production of new LDPE films with enhanced hydrophilic properties.

Comparative study of gamma-irradiated PP and PE polyolefins part 1: Identification and quantification of radicals using electron paramagnetic resonance

“…Its use for the control of the molecular modification of materials in solid state is now gaining a lot of interest. Lately, many researchers have investigated the impact of g-irradiation on the properties of genuine polymers and their blends as well as on composite materials [16,17,6,3,43,2,19,31,44,26,37,11,47]. Indeed, such highly energetic irradiations yield bond cleavages and free radicals allowing chemical rearrangements or oxidation in the presence of air, crosslinking and further chain scission reactions in the g-irradiated material.…”

“…Indeed, they are rarely identified at the molecular level. Most of the studies focus on the final products of the radical reactions coupling Electron Paramagnetic Resonance (EPR) with other techniques of characterizations [5,4,19]). Indeed, an EPR spectrum can rapidly become very complex since it may contain a superimposition of radical signals while each of them are often made of several peaks [16,36,50].…”

Surface texturing of polytetrafluoroethylene by hot embossing

“…In many cases important task is modifying of surface wettability. For example, good wetting is necessary in some bioapplications, whereas hydrophobic properties are essential for self-clean surfaces [1,2]. Hydrophobicity can be enhanced by using materials of lower surface energy and/or by increasing surface roughness.…”

Organic Solvents Transport Through Alkali-Treated Agro-waste Microfibre Incorporated with Low Density Polyethylene Composites

“…Low-density polyethylene (LDPE) is a semi-crystalline solid with a reasonable degree of crystallinity in the 50-60% range that leads to several properties such as opacity, tensile strength, tear strength, rigidity and chemical resistance, flexibility even at a low temperature [23,24]. LDPE is one of the most commonly used thermoplastics to develop composites reinforced by different natural materials, cellulose [25], lignin [26], starch [27].…”