Toughening and functionalizing degradable polylactic acid films using MXene and its surface-modified derivatives

Name: Autchara Kham-ek

keyword: Polylactic acid

; PLA

; MXene

; Alkyl ketene dimer

; Composites

Abstract: Polylactic acid (PLA) is a degradable polymer with widespread applications in packaging, biomedical devices, and electronics. However, high brittleness and limited mechanical strength restrict its use in load-bearing applications. This study aims to enhance the mechanical, electrical, and barrier properties of PLA films by incorporating MXene (Ti₃C₂Tₓ) and alkyl ketene dimer (AKD)-modified MXene (MX-D). MXene was synthesized from the MAX phase (Ti₃AlC₂) using fluoride-based etching, followed by AKD modification through ball milling to improve dispersion and compatibility with the PLA matrix. Composite films were fabricated via a solution casting method, with varying MXene contents (5-30 wt%), to evaluate their impact on the film’s structural and functional performance. The mechanical properties demonstrated that adding MXene significantly improved tensile strength and Young’s modulus, with the highest reinforcement observed at 15 wt% MXene. However, at 30 wt%, agglomeration reduced ductility, highlighting the need for optimized filler dispersion. Alternatively, AKD modification effectively enhanced MXene distribution, increasing elongation at break and improving the toughness of the composite films. For example, the elongation at break increased from 4.6% in neat PLA to 26.3% with 5 wt% MXene. With AKD-modified MXene, it further increased to 54.7%. The results demonstrate a significant improvement in ductility and mechanical performance. The thermal properties indicated that MXene acted as a nucleating agent, promoting higher PLA crystallinity, while AKD-modified MXene disrupted polymer alignment, reducing crystallinity. UV-Vis spectroscopy revealed that increasing MXene content reduced light transmittance, making these composites suitable for UV-blocking applications. Additionally, water vapor permeability (WVP) analysis showed that 5 wt% MXene improved moisture barrier properties, enhancing its potential for food packaging applications. The electrical conductivity results confirmed that at 30 wt% MXene, the composite exhibited a conductivity of 2.91×10-⁵ S/cm, while a 50 wt% content significantly increased conductivity to 1.22×10-² S/cm, demonstrating the potential for electromagnetic shielding and antistatic applications in real-world flexible electronics and packaging. The combined mechanical strength, moisture resistance, and electrical conductivity improvements enable PLA/MXene and PLA/MX-D composites to be multifunctional materials for advanced applications, especially in flexible electronics, protective coatings, and sustainable packaging. Future research should focus on optimizing large-scale fabrication techniques such as extrusion and injection molding, along with long-term stability assessments to ensure these composite materials’ industrial viability and environmental sustainability.

Thammasat University. Thammasat University Library

Address: BANGKOK

Email: preserv@tu.ac.th

Name: Pakorn Opaprakasit

Role: advisor

Name: Atitsa Petchsuk

Role: co-advisor

Created: 2025

Modified: 2025-11-24

Issued: 2025-11-24

วิทยานิพนธ์/Thesis

application/pdf

eng

DegreeName: Master of Engineering

Level: Master's Degree

Descipline: Engineering Technology

Grantor: Thammasat University

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