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Iranian Polymer Journal (2018) 27:433–443
https://doi.org/10.1007/s13726-018-0621-x
ORIGINAL RESEARCH
Dynamic mechanical properties of bacterial cellulose nanofibres
Hadi Hosseini
1
· Mehrdad Kokabi
1
· Seyyed Mohammad Mousavi
2
Received: 7 December 2017 / Accepted: 10 April 2018 / Published online: 19 May 2018
© Iran Polymer and Petrochemical Institute 2018
Abstract
In this work, dynamic mechanical properties of the grown bacterial cellulose (BC) nanofibers were investigated. BC pellicles
were fabricated using bacterial fermentation (Gluconacetobacter xylinus). The morphology results confirmed that the dried
BC at ambient conditions could be categorized as a xerogel. The thermal dynamic mechanical analysis results indicated that
the bound water in bacterial cellulose structure had a very significant effect on thermal and dynamic mechanical properties
of BC pellicles. The results of dehydration kinetics study showed that the main mechanism governing water loss of BC was
Fickian diffusion. The glass transition temperatures (T
g
) of the BC dried at 25 °C (ambient temperature) and 105 °C were
estimated − 33 and − 18 °C, respectively. This discrepancy can be attributed to the plasticizing effect of the bound water of
BC dried at ambient temperature. Furthermore, the results indicated that its modulus drop smaller than one order of magni-
tude can be attributed to its high crystalline nature. The storage modulus versus frequency increased due to the limitation of
the relaxation process of the polymer chains. Moreover, the relaxation time distribution was achieved from the slope of the
modulus master curve versus logarithmic frequency. As a result, BC exhibited a solid-like behavior.
Keywords Bacterial cellulose nanofibres · Gluconoacetobacter xylinus · Dehydration kinetic · Xerogels · Dynamic
mechanical properties
Introduction
Bacterial cellulose (BC) with a chemical structure (a poly-
saccharide consisting of a linear chain of β(1→4) linked
d
-glucose units) identical to plant-based cellulose and crys-
talline form of cellulose I is a biodegradable sustainable
biomass [1]. BC has many inimitable and very interesting
characteristics including high degree of polymerization,
purity and crystalline degree that results in high strength and
modulus. BC also has a 3-D network structure with highly
porous structure and high surface area due to small fibre
diameter (below 100 nm), resulting in a high water-holding
capacity. Because of great thermal stability, superior envi-
ronmental biodegradability and strong biocompatibility, BC
has recently drawn significant attention for various applica-
tions including a food product known as nata-de-coco [2],
oil/water separation [3], foldable super capacitors [4], dia-
phragms for loudspeakers, packaging film for food [5], nano-
reinforced materials [6], wound dressing and drug delivery
systems [7], and artificial blood vessels [8].
Among the bacteria genera of Acetobacter, Rhizobium,
Agrobacterium, and Sarcina, which can produce cellulose,
the most commonly used bacterium for producing white
gelatinous bacterial cellulose pellicle is Gluconoacetobacter
xylinus (G. xylinus). It is a rod-shaped aerobic Gram-nega-
tive and non-pathogenic bacteria, with an ability to produce
cellulose from a wide range of carbon/nitrogen sources [9].
There is a wide range of studies on structural charac-
terization of bacterial cellulose using Fourier transform
infrared spectroscopy (FTIR) [10], X-ray diffraction
(XRD)analysis [11] and mechanical tests [12]. Characteri-
zation of the cellulose acetate butyrate/cellulose nanocrys-
tals nanocomposites by differential scanning calorimetry
Electronic supplementary material The online version of this
article (https ://doi.org/10.1007/s1372 6-018-0621-x) contains
supplementary material, which is available to authorized users.
* Mehrdad Kokabi
mehrir@modares.ac.ir
1
Department of Polymer Engineering, Faculty of Chemical
Engineering, TarbiatModares University, P.O.
Box 14115-114, Tehran, Iran
2
Department of Biotechnology, Faculty of Chemical
Engineering, TarbiatModares University,
P.O. Box 14115-114, Tehran, Iran
@Phil_Robichaud
@deepthiw
@JoseServera