TY - JOUR
T1 - 3D printing of thermal insulating polyimide/cellulose nanocrystal composite aerogels with low dimensional shrinkage
AU - Feng, Chiao
AU - Yu, Sheng Sheng
N1 - Funding Information:
Acknowledgments: We are grateful for the valuable discussion and inputs from Mitsuru Ueda. We thank the Ministry of Science & Technology in Taiwan for financial support (Young Scholar Fellowship Program, MOST 108-2636-E-006-005 and 109-2636-E-006-005). We also thank the support by Higher Education Sprout Project, Ministry of Education to the Headquarters of University Advancement at National Cheng Kung University (NCKU). The authors gratefully acknowledge the use of Bruker Avance III HD 400 NMR spectrometer (NMR000800) of MOST 108-2731-M-006-001 belonging to the Core Facility Center of National Cheng Kung University.
Funding Information:
This research was funded by the Ministry of Science & Technology in Taiwan, grant No. 108-2636-E-006-005, 109-2636-E-006-005 and 110-2222-E-006-009-MY3.Acknowledgments: We are grateful for the valuable discussion and inputs from Mitsuru Ueda. We thank the Ministry of Science & Technology in Taiwan for financial support (Young Scholar Fellowship Program, MOST 108-2636-E-006-005 and 109-2636-E-006-005). We also thank the support by Higher Education Sprout Project, Ministry of Education to the Headquarters of University Advancement at National Cheng Kung University (NCKU). The authors gratefully acknowledge the use of Bruker Avance III HD 400 NMR spectrometer (NMR000800) of MOST 108-2731-M-006-001 belonging to the Core Facility Center of National Cheng Kung University.
Funding Information:
Funding: This research was funded by the Ministry of Science & Technology in Taiwan, grant No. 108-2636-E-006-005, 109-2636-E-006-005 and 110-2222-E-006-009-MY3.
Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
PY - 2021/11/1
Y1 - 2021/11/1
N2 - Polyimide (PI)-based aerogels have been widely applied to aviation, automobiles, and thermal insulation because of their high porosity, low density, and excellent thermal insulating ability. However, the fabrication of PI aerogels is still restricted to the traditional molding process, and it is often challenging to prepare high-performance PI aerogels with complex 3D structures. Interestingly, renewable nanomaterials such as cellulose nanocrystals (CNCs) may provide a unique approach for 3D printing, mechanical reinforcement, and shape fidelity of the PI aerogels. Herein, we proposed a facile water-based 3D printable ink with sustainable nanofillers, cellulose nanocrystals (CNCs). Polyamic acid was first mixed with triethylamine to form an aqueous solution of polyamic acid ammonium salts (PAAS). CNCs were then dispersed in the aqueous PAAS solution to form a reversible physical network for direct ink writing (DIW). Further freeze-drying and thermal imidization produced porous PI/CNC composite aerogels with increased mechanical strength. The concentration of CNCs needed for DIW was reduced in the presence of PAAS, potentially because of the depletion effect of the polymer solution. Further analysis suggested that the physical network of CNCs lowered the shrinkage of aerogels during preparation and improved the shape-fidelity of the PI/CNC composite aerogels. In addition, the composite aerogels retained low thermal conductivity and may be used as heat management materials. Overall, our approach successfully utilized CNCs as rheological modifiers and reinforcement to 3D print strong PI/CNC composite aerogels for advanced thermal regulation.
AB - Polyimide (PI)-based aerogels have been widely applied to aviation, automobiles, and thermal insulation because of their high porosity, low density, and excellent thermal insulating ability. However, the fabrication of PI aerogels is still restricted to the traditional molding process, and it is often challenging to prepare high-performance PI aerogels with complex 3D structures. Interestingly, renewable nanomaterials such as cellulose nanocrystals (CNCs) may provide a unique approach for 3D printing, mechanical reinforcement, and shape fidelity of the PI aerogels. Herein, we proposed a facile water-based 3D printable ink with sustainable nanofillers, cellulose nanocrystals (CNCs). Polyamic acid was first mixed with triethylamine to form an aqueous solution of polyamic acid ammonium salts (PAAS). CNCs were then dispersed in the aqueous PAAS solution to form a reversible physical network for direct ink writing (DIW). Further freeze-drying and thermal imidization produced porous PI/CNC composite aerogels with increased mechanical strength. The concentration of CNCs needed for DIW was reduced in the presence of PAAS, potentially because of the depletion effect of the polymer solution. Further analysis suggested that the physical network of CNCs lowered the shrinkage of aerogels during preparation and improved the shape-fidelity of the PI/CNC composite aerogels. In addition, the composite aerogels retained low thermal conductivity and may be used as heat management materials. Overall, our approach successfully utilized CNCs as rheological modifiers and reinforcement to 3D print strong PI/CNC composite aerogels for advanced thermal regulation.
UR - http://www.scopus.com/inward/record.url?scp=85117940837&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85117940837&partnerID=8YFLogxK
U2 - 10.3390/polym13213614
DO - 10.3390/polym13213614
M3 - Article
AN - SCOPUS:85117940837
SN - 2073-4360
VL - 13
JO - Polymers
JF - Polymers
IS - 21
M1 - 3614
ER -