Journal
CHEMICAL ENGINEERING JOURNAL
Volume 419, Issue -, Pages -Publisher
ELSEVIER SCIENCE SA
DOI: 10.1016/j.cej.2021.129440
Keywords
Nanofibrillated cellulose; Quaternization; Borylation; Flame retardancy; Fire-protective coating
Categories
Funding
- Ningbo 3315 Innovative Team Project of China
- National Natural Science Foundation of China [51991355]
- Zhejiang Provincial Public Welfare Project of China [2016C33029]
- Opening Fund of CAS Key Laboratory of Engineering Plastics & Institute of Chemistry (China)
- Scientific Research Foundation of NingboTech University [20200323Z0018, 20201206Z0202]
Ask authors/readers for more resources
The study successfully prepared intrinsically flame-retardant nanofibrillated cellulose (NFC) from kraft and unbleached bamboo pulps using a three-step strategy. The resulting materials showed improved flame resistance while maintaining mechanical and optical properties, with potential applications in various fields including thermal insulation and electronics.
Developing functional nanocellulose-based materials while well maintaining their inherent excellent attributes is crucial to achieve the value-added applications. However, their inherent flammability largely limits their potential applications in many fields with fire-safety concerns. In this work, an intrinsically flame-retardant nanofibrillated cellulose (NFC) was successfully prepared from kraft and unbleached bamboo pulps, respectively, via a three-step strategy involving quaternized pre-treatment, mechanical disintegration and subsequent borylation. TEM images show that the well-defibrillated cellulose nanofibrils with an average diameter of 5-9 nm were successfully obtained. The morphological, physicochemical, mechanical, thermal and flame-retardant characteristics of NFC suspensions, and their resulting films were systematically characterized. The borylated NFC film from the kraft pulp (B/Q-NFC) exhibits remarkably improved char yield while retaining high degree of fibrillation, optical transparency and mechanical properties of the Q-NFC one. Despite relatively lower optical transmittance and tensile strength, the lignin-containing NFC (L-Q-NFC) from unbleached pulp exhibits better thermal stability and outstanding UV-shielding function. Flame-retardant properties of borylated NFC samples were comprehensively investigated in terms of microscale combustion calorimetry (MCC), limiting oxygen index (LOI), vertical burning, and cone calorimetry tests. A synergistic effect was noted between B and lignin species in promoting flame resistance of Q-NFC matrix (L-B/Q-NFC). When being used as flame-retardant coatings on the filter paper and PET film, both of borylated NFC films display excellent flame-retardancy and smoke-suppression effects. In combination with of surface and bulk chemical composition analysis, TGA results as well as oxygenpermeability and thermal diffusivity measurements, the flame-retardant mechanism of borylated NFC films was elucidated. These favorite features enable them to act as sustainable fire-protective coatings for many fields such as thermal insulation, electronics, separators for lithium-ion battery, etc.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available