Polymer Degradation Under Microwave Irradiation

Abstract

Development of advanced, environmentally friendly and energy-saving techniques for the chemical recycling of polymers is of paramount importance in the polymer industry. Understanding polymer degradation is the scientific key behind this technological challenge. Recent research on the application of microwave irradiation to polymer degradation is presented in this review. Results have shown the potential advantage of microwaves for complete polymer degradation in a significantly reduced time scale compared with conventional heating. The benefits of using microwave irradiation in the degradation of polyesters [e.g. poly(ethylene terephthalate) and polycarbonate], polyurethanes, polyamides, poly[alkyl (meth)acrylates], polystyrene and other polymers is presented. Moreover, the effect of microwave heating on the pyrolysis of commodity polymers such as polyethylene, is also discussed. Finally, the double role of materials used traditionally as solvents, reagents or catalysts, but now also as microwave absorbers in polymer degradation is explored.

Organo‐sulfonic acid catalyzed degradation kinetics and thermodynamic studies of nylon‐6 by hydrothermal method

“…It can be concluded that the catalytic activity for sulfuric acid and MSA are similar. 15 Similarly, Sulfuric acid shows excellent catalytic activity at 80 C in the degradation of nylon. 2 The mineral and MSA's counterion is similar in size, and binding energy is more petite and dissociates readily at lower energy.…”

“…Specific advantages of microwave irradiation as a heating technique compared with conventional heating include rapid and no-contact heating with high specificity, shorter reaction times, great convenience, and significant overall cost saving. 15 Klun et al studied the microwave acidic depolymerization of nylon-6 using phosphoric acid and zinc-based salts. 16,17 Furthermore, methane sulfonic acid (MSA) was used as a replacement for sulfuric acid for esterification of Palm fatty acids to produce bio-diesel evaluating the effect of water, type, and concentration of catalysts.…”

Evaluation of mechanical and thermal properties of microwave irradiated poly (styrene-co-methyl methacrylate)/graphene nanocomposites

“…[23] The irradiation process causes major reactions such as cross-linking, chain scission (degradation), formation of oxygen-based functionalities (oxidation), and grafting (in the presence of monomers). [24] Similarly, when radiation is absorbed on the surface of graphene, defects form on graphene [25] which results in a change of the structure of graphene. This free radical formation in polymer chains and disorder in graphene structure after irradiation may provide improved dispersion and hence a strong interfacial interaction between the graphene and the polymer matrix.…”

Investigation of Degradation of Composites Based on Unsaturated Polyester Resin and Vinyl Ester Resin

“…It is known that oxygen in the air, high temperature, hydrolysis associated with a humid atmosphere, light with a wavelength (>300 nm), biological attack, mechanical stress, contact with aggressive liquids, high-energy radiation and some living organisms have a possible detrimental effect on polymers [38][39][40][41][42][43][44][45][46]. Therefore, it makes sense to investigate the degradation conditions for such composites.…”