Joint physicochemical effects of UV-B irradiation on microplastics formation: The case of poly(vinyl chloride) and poly(methyl methacrylate)

IF 6.3 2区化学 Q1 POLYMER SCIENCE

Polymer Degradation and Stability Pub Date : 2025-04-03 DOI:10.1016/j.polymdegradstab.2025.111366

Nina Maria Ainali , Dimitrios N. Bikiaris , Dimitra A. Lambropoulou

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引用次数: 0

Abstract

The combination of rapid growth in global plastic production and insufficient waste management has led to severe environmental pollution and resource depletion, rendering the degradation of plastics into microplastics (MPs) an intensified concern. Among the different mechanisms driving the MP formation, UV-induced photodegradation holds a crucial role, since it facilitates the initiation of chemical transformation, such as chain scission, oxidation, and crosslinking reactions, which result in physicochemical alterations and fragmentation of polymers. With the most expanded research been conducted on polyolefins, there still remains a gap in understanding the photodegradation mechanisms of other widely used polymer types, such as poly(vinyl chloride) (PVC) and poly(methyl methacrylate) (PMMA). Herein, the UV-B-induced aging of PVC and PMMA thin films was investigated over a two-month period. An inclusive sequence of characterization and analytical techniques, such as Fourier-transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Pyrolysis–Gas Chromatography/Mass Spectrometry (Py–GC/MS), was employed to evaluate the physicochemical, thermal, morphological, and chemical changes of the studied polymers. Significant structural and chemical alterations were found in both studied polymers, underscoring their vulnerability to UV-induced oxidation processes with the FTIR spectra's identification of new oxidation products. While mechanical performance deterioration during UV irradiation suggested the progressive fragmentation of polymers, potentially causing the formation of MPs, SEM images and water contact angle values showed the notable morphological and hydrophilicity changes of the irradiated samples in comparison to the virgin one. Additionally, according to Py–GC/MS analysis, the relative abundance of pyrolysis products changed during the UV exposure testing as well. Furthermore, during photo-aging, there were notable variations in the quantities of pyrolytic marker compounds, which are frequently utilized in MPs analysis in ongoing research. All aspects considered, these results highlight the necessity of deepened research into the aging processes of common polymer types since they present significant obstacles to the precision and reliability of MPs quantification in real environmental samples.

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来源期刊

Polymer Degradation and Stability 化学-高分子科学

CiteScore

10.10

自引率

10.20%

发文量

325

审稿时长

23 days

期刊介绍： Polymer Degradation and Stability deals with the degradation reactions and their control which are a major preoccupation of practitioners of the many and diverse aspects of modern polymer technology. Deteriorative reactions occur during processing, when polymers are subjected to heat, oxygen and mechanical stress, and during the useful life of the materials when oxygen and sunlight are the most important degradative agencies. In more specialised applications, degradation may be induced by high energy radiation, ozone, atmospheric pollutants, mechanical stress, biological action, hydrolysis and many other influences. The mechanisms of these reactions and stabilisation processes must be understood if the technology and application of polymers are to continue to advance. The reporting of investigations of this kind is therefore a major function of this journal. However there are also new developments in polymer technology in which degradation processes find positive applications. For example, photodegradable plastics are now available, the recycling of polymeric products will become increasingly important, degradation and combustion studies are involved in the definition of the fire hazards which are associated with polymeric materials and the microelectronics industry is vitally dependent upon polymer degradation in the manufacture of its circuitry. Polymer properties may also be improved by processes like curing and grafting, the chemistry of which can be closely related to that which causes physical deterioration in other circumstances.