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<p>The dispersion of multi-walled carbon nanotubes (MWCNTs) into epoxy-based shape memory polymer (SMP) was investigated to enhance their mechanical, viscoelastic and shape memory behavior. SMP composites were synthesized with varying MWCNT loadings (0.1, 0.2, 0.3, 0.4 and 0.5 wt.%) and characterized using X-ray diffraction (XRD), ultraviolet–visible-near infrared (UV–Vis-NIR) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy and dynamic mechanical analysis (DMA). Mechanical testing was performed through tensile testing, flexural testing, fracture toughness testing and impact testing, and later shape memory behavior was evaluated in tensile mode. XRD analysis indicated effective integration of MWCNT into the epoxy matrix, with an upward shift and increased intensity of characteristic peak of composites, signifying strong interfacial bonding. FTIR spectra confirmed no chemical interaction between epoxy and MWCNT, while UV–Vis-NIR analysis revealed a decrease in the optical bandgap with MWCNT addition, attributed to defect-induced charge carrier levels. Dynamic mechanical analysis showed enhanced storage modulus and damping characteristics with increased MWCNT loading. Tensile and flexural results demonstrated that 0.3 wt.% MWCNT provided optimal reinforcement, leading to an 30.65% increase in tensile strength (from 48.77 to 63.72&#xa0;MPa) and a 10.20% improvement in flexural strength (from 105.58 to 116.35&#xa0;MPa) compared to pristine epoxy. The single-edge notched bend (SENB) fracture toughness (K<sub>1C</sub>) increased by 31.46%, reaching 3.51&#xa0;MPa∙m<sup>1/2</sup> at 0.3 wt.% MWCNT, while impact properties showed modest improvement. Fractographic analysis revealed that MWCNT improved fracture toughness by obstructing crack propagation, though high loadings led to reduced performance due to agglomerations. Shape memory behavior analysis showed decreased shape fixity and recovery ratios with MWCNT addition but faster recovery times. The shape recovery time significantly decreased by 45.5% (from 363 to 198&#xa0;s at 0.3 wt.% MWCNT), demonstrating a faster recovery response. The study highlights that 0.3 wt.% MWCNT is optimal for enhancing the properties of epoxy-based SMP composites, offering significant improvements in mechanical and thermal performance, with potential applications in advanced engineering fields.</p>

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Investigation of MWCNT dispersion in epoxy-based shape memory polymer using probe ultrasonication: characterization and mechanical properties evaluation

  • 期刊论文

  • 发表日期：

    2025年5月30日

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  • Avadesh Yadav,
  • Satish Kumar,
  • Abhishek Kumar

摘要

The dispersion of multi-walled carbon nanotubes (MWCNTs) into epoxy-based shape memory polymer (SMP) was investigated to enhance their mechanical, viscoelastic and shape memory behavior. SMP composites were synthesized with varying MWCNT loadings (0.1, 0.2, 0.3, 0.4 and 0.5 wt.%) and characterized using X-ray diffraction (XRD), ultraviolet–visible-near infrared (UV–Vis-NIR) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy and dynamic mechanical analysis (DMA). Mechanical testing was performed through tensile testing, flexural testing, fracture toughness testing and impact testing, and later shape memory behavior was evaluated in tensile mode. XRD analysis indicated effective integration of MWCNT into the epoxy matrix, with an upward shift and increased intensity of characteristic peak of composites, signifying strong interfacial bonding. FTIR spectra confirmed no chemical interaction between epoxy and MWCNT, while UV–Vis-NIR analysis revealed a decrease in the optical bandgap with MWCNT addition, attributed to defect-induced charge carrier levels. Dynamic mechanical analysis showed enhanced storage modulus and damping characteristics with increased MWCNT loading. Tensile and flexural results demonstrated that 0.3 wt.% MWCNT provided optimal reinforcement, leading to an 30.65% increase in tensile strength (from 48.77 to 63.72 MPa) and a 10.20% improvement in flexural strength (from 105.58 to 116.35 MPa) compared to pristine epoxy. The single-edge notched bend (SENB) fracture toughness (K1C) increased by 31.46%, reaching 3.51 MPa∙m1/2 at 0.3 wt.% MWCNT, while impact properties showed modest improvement. Fractographic analysis revealed that MWCNT improved fracture toughness by obstructing crack propagation, though high loadings led to reduced performance due to agglomerations. Shape memory behavior analysis showed decreased shape fixity and recovery ratios with MWCNT addition but faster recovery times. The shape recovery time significantly decreased by 45.5% (from 363 to 198 s at 0.3 wt.% MWCNT), demonstrating a faster recovery response. The study highlights that 0.3 wt.% MWCNT is optimal for enhancing the properties of epoxy-based SMP composites, offering significant improvements in mechanical and thermal performance, with potential applications in advanced engineering fields.