Electroactive shape memory polyurethane composites reinforced with octadecyl isocyanate-functionalized multi-walled
Yadong Sun1, Jiachi Teng1, Yi Kuang2
1Research Institute for Biomaterials, Tech Institute for Advanced Materials, College of Materials Science and Engineering, Nanjing Tech University, Nanjing, China.
Frontiers in Bioengineering and Biotechnology
|August 1, 2022
Summary
Functionalized carbon nanotubes improve dispersion in shape memory polymers, enabling electroactive composites for flexible electronics. These composites demonstrate electrical conductivity and rapid shape recovery when stimulated by voltage.
Area of Science:
- Materials Science
- Polymer Chemistry
- Nanotechnology
Background:
- Shape memory polymers (SMPs) offer diverse applications, with electrically driven variants gaining attention for their unique deformation behaviors.
- Carbon nanotubes (CNTs) are ideal conductive fillers for SMPs but suffer from poor dispersion in polymer matrices.
- Hydroxylated multi-walled carbon nanotubes (MWCNT-OHs) require functionalization to enhance their compatibility with polymers.
Purpose of the Study:
- To improve the dispersion of carbon nanotubes in shape memory polyurethane (SMPU) matrices.
- To develop electroactive shape memory composites with enhanced electrical and shape memory properties.
- To investigate the effect of functionalized carbon nanotubes on the thermal and mechanical properties of SMPU.
Main Methods:
- Functionalization of MWCNT-OHs with octadecyl isocyanate to create i-MWCNTs.
- Synthesis of SMPU using polycaprolactone diol, hexamethylene diisocyanate, and 1,4-butanediol.
- Fabrication of SMPU/i-MWCNT composites by blending SMPU with i-MWCNTs.
Main Results:
- Functionalized i-MWCNTs showed significantly improved dispersibility in solvents and the SMPU matrix compared to MWCNT-OHs.
- Addition of i-MWCNTs reduced SMPU crystallinity, decreased hydrogen bond index and melting temperature, but increased thermal decomposition temperatures.
- SMPU/i-MWCNT composites exhibited electrical conductivity at 0.5 wt% i-MWCNT, with enhanced conductivity at higher loadings. Composites with >1 wt% i-MWCNT showed rapid heating (>60°C in 140s) and shape recovery (120s at 30 eV).
Conclusions:
- Octadecyl isocyanate functionalization effectively enhances carbon nanotube dispersion in SMPU.
- The developed SMPU/i-MWCNT composites possess excellent electroactive and shape memory properties.
- These functionalized CNT-based composites show significant potential for applications in flexible electronics and other advanced fields.
