Isolation of cellulose nanofibrils from Triodia pungens via different mechanical methods

Abstract

Triodia pungens is one of the 69 species of an Australian native arid grass which covers approximately 27 % of the Australian landmass. In this study, we report that very long and thin cellulose nanofibrils can readily be isolated from Triodia pungens biomass using unrivalled mild chemical pulping, followed by several mechanical fibrillation methods. After a typical pulping process which includes washing, delignification and bleaching steps, mechanical fibrillation was performed via high pressure homogenization, ultrasonication and high energy ball milling using relatively minimal energy in all approaches. Cellulose nanofibrils with an average diameter of below 10 nm and a length of several microns were obtained. It also has been shown that the nanofibrils obtained from Triodia pungens have a crystallinity index of about 69 %, and a thermal stability of up to 320°C. The sheets produced from high aspect ratio nanofibrils prepared by high pressure homogenization, also demonstrated a very high work at fracture. By evaluating the deconstruction strategies and the performance of nanofibril sheets, we report that the highperformance cellulose nanofibrils can be processed from arid grass bleached pulp with unusually low energy input.

Recent advances in starch–clay nanocomposites

“…As a result of low fillers and low density of polymers leads to the formation of nanocomposite in particular system [29]. Nanocomposite technology has a great importance in the preparation of synthetic and natural polymers based nanocomposites [30][31]. Toyota has earlier reported on the improved properties of nylon-6 through the exfoliated clay.…”

Facile Tuning of the Surface Energy of Cellulose Nanofibers for Nanocomposite Reinforcement

“… 2 , 8 However, although sodium hydroxide is commonly used as a pretreatment process for biomass, only a few studies exclusively employed alkali treatment to process lignocellulosic biomass 13 − 16 and rarely prepared CNF. 8 , 17 On the basis of our knowledge, there is no study on the influence of controlled alkali treatment performed at such a low concentration (lower than 2 w/v % NaOH) on the physical, chemical, and thermal properties of the fibrillated CNF.…”

Scalable processing of thermoplastic polyurethane nanocomposites toughened with nanocellulose

“…According to Moon et al [5], which further categorises nanocellulose types by their dimensions, typical CNF have a length between 0.5-2 µm and a width of about 4-20 nm, whereas a rod-like cellulose nanocrystal (CNC) show a length around 0.05-0.5 µm and width of 1-30 nm. A CNF are usually produced via mechanical shearing methods like ultrasonication, homogenisation, grinding, microfluidisation or milling in combination with enzymatic and/or chemical pretreatments [9][10][11], whereas CNCs are isolated via acid hydrolysis, enzymatic treatment, hydrothermal treatment, ultrasonication and mechanical methods, or combinations thereof. [12][13][14] The reinforcing potential of nanocellulose has been exploited not only due to its sustainability and reliability but more so due to its virtuous individual mechanical properties such as high specific strength and modulus, and the potential to retain transparency in the nanocomposite materials.…”

“…We have recently explored spinifex as a source of high-aspect ratio nanofibrils capable of being extracted using comparatively green methods and very low energy consumption. [10,11] This was done in order to remove the excess aqueous acid and the dissolved amorphous lignocellulosic components. Then, the nanocellulose suspension was dialysed in deionised water until the pH reached 7, ultrasonicated at 25 % amplitude, at a frequency of 20 kHz for 20 minutes with output energy of 500W using an ultrasonic probe (Model Q500 Sonicator, from QSonica, Newtown, United States) and then freeze-dried.…”