Issue 26, 2025, Issue in Progress

Investigating laser-induced bond breaking in high-density polyethylene pyrolysis

Abstract

A particular laser harmonic with an effective combination of process parameters can break plastic bonds by surpassing the dissociation threshold. Exploring this direction is imperative to uncover new physics and chemistry related to laser-high-density polyethylene (HDPE) interactions and to understand the phenomena occurring during laser induced degradation. An experiment was conducted in an open-air environment using the first (1064 nm), second (532 nm), and fourth (266 nm) harmonics at a 20 Hz repetition rate, with pulse energies of 5–40 mJ for the first and second harmonics, and 3–10 mJ for the fourth harmonic. The findings revealed that all laser harmonics broke HDPE bonds, with the fourth harmonic being the most effective in directly breaking bonds, particularly C–H bonds, which was evident from a prominent Hα peak at 656.3 nm. The results demonstrate initial, partial, and post-bond breaking, which can address deficiencies in laser-HDPE recycling and enable laser-induced HDPE pyrolysis, which has not been investigated. Optical microscopic analysis showed that craters formed by the fourth harmonic were wider and exhibited more efficient photon absorption with minimal ablation. Additionally, a high confidence interval (R2) value of 0.9758 with increased electron density and plasma temperatures, further supports the efficiency of bond breaking.

Graphical abstract: Investigating laser-induced bond breaking in high-density polyethylene pyrolysis

Supplementary files

Transparent peer review

To support increased transparency, we offer authors the option to publish the peer review history alongside their article.

View this article’s peer review history

Article information

Article type
Paper
Submitted
26 Apr 2025
Accepted
28 May 2025
First published
23 Jun 2025
This article is Open Access
Creative Commons BY-NC license

RSC Adv., 2025,15, 21089-21107

Investigating laser-induced bond breaking in high-density polyethylene pyrolysis

R. A. U. Nabi, H. A. Khawaja, Y. Liu, C. Yang and T. Wang, RSC Adv., 2025, 15, 21089 DOI: 10.1039/D5RA02920A

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements