115
the use of several matrices such as polysaccharides, proteins, lipids, biobased or
fossil-based bioplastics (polycaprolactone - PCL, polyvinyl alcohol - PVA, PLA,
etc.) acting as a host to these nanomaterials (Lee et al. 2009; De Mesquita et al.
2010; Gutiérrez and Alvarez 2017e; Alvarado et al. 2018; Gutiérrez 2018g; Niu
et al. 2018).
Cellulose-containing composite films and their characterization methods are
summarized in Table 6.1. As shown in the table, the amount of cellulose nanomaterial in the composite films is generally between 1 to 10%, but the formation of
composite films with extreme levels of nanocellulose is also tested up to 100%.
These materials are frequently evaluated in terms of their chemical, mechanical,
optical, physical and thermal properties.
The mechanical strength of nanocomposite films depends on the matrix of the
composite, the source of nanocellulosic material, the production methods of nanocellulose, the addition of other minor constituents to form the film (plasticizer etc.)
and the amount of nanocellulose that is incorporated into the film (Khan et al. 2014;
Ilyas et al. 2018; Vilarinho et al. 2018). Kwak et al. (2018) studied the effects of
bamboo-derived cellulose nanofibers on the nanocomposite film properties composed of silk sericin using glycerin as a plasticizer. They concluded that the σ max of
the films increased from 9.47 MPa (without cellulose nanofiber) to a maximum of
28.20 MPa with the addition of 10% cellulose nanofiber, while the E of the films
increased from 320.42 MPa (control) to 805.96 MPa for 20% nanocellulosecontaining films (Kwak et al. 2018). However, ε b values decreased linearly with
respect to the increase in the amount of cellulose (Kwak et al. 2018). Similarly, the
addition of nanocellulose to agar-based composite films increased the σ max and E
values in the films containing up to 3% filler, and the ε b value of composite film
containing 5% nanocellulose was higher than the other cellulose levels (Shankar
and Rhim 2016b). Shankar and Rhim (2016b) also studied the effect of incorporating microcrystalline cellulose at the same levels of nanocellulose, and the σ max , ε b
and E values of these films were comparably lower than nanocellulose-containing
films and even lower than the control film. As an extreme condition, Robles et al.
(2016) studied on the composite films made from cellulose nanofibers (90–100%)
containing chitin nanocrystals between 0–10%. The σ max and E values did not vary
significantly with the increasing amount of cellulose nanofiber, although the highest
ε b (7.57%) value belonged to the 100% cellulose nanofiber film (Robles et al. 2016).
Ilyas et al. (2018) produced a nanocomposite film containing lowest level of cellulose (0–1%) using sugar palm starch and sugar palm nanocellulose. The incorporation of nanocellulose improved the σ max and E values up to a 0.5% content, although
the 1% nanocellulose did not have a similar behavior due to the uneven distribution
and agglomeration of the nanocellulose (Ilyas et al. 2018). In addition, the addition
of sugar palm nanocellulose reduced the ε b values of the films compared to the control sample (Ilyas et al. 2018).
The mechanical properties are also influenced from the minor constituents that
are added for film-forming capacity of nanocellulose-containing composite films.
For example, the addition of gum Arabic to nanocellulose/starch composite
films resulted in higher σ max and ε b values compared to the pure starch and
6 Functional Biobased Composite Polymers for Food Packaging Applications
the use of several matrices such as polysaccharides, proteins, lipids, biobased or
fossil-based bioplastics (polycaprolactone - PCL, polyvinyl alcohol - PVA, PLA,
etc.) acting as a host to these nanomaterials (Lee et al. 2009; De Mesquita et al.
2010; Gutiérrez and Alvarez 2017e; Alvarado et al. 2018; Gutiérrez 2018g; Niu
et al. 2018).
Cellulose-containing composite films and their characterization methods are
summarized in Table 6.1. As shown in the table, the amount of cellulose nanomaterial in the composite films is generally between 1 to 10%, but the formation of
composite films with extreme levels of nanocellulose is also tested up to 100%.
These materials are frequently evaluated in terms of their chemical, mechanical,
optical, physical and thermal properties.
The mechanical strength of nanocomposite films depends on the matrix of the
composite, the source of nanocellulosic material, the production methods of nanocellulose, the addition of other minor constituents to form the film (plasticizer etc.)
and the amount of nanocellulose that is incorporated into the film (Khan et al. 2014;
Ilyas et al. 2018; Vilarinho et al. 2018). Kwak et al. (2018) studied the effects of
bamboo-derived cellulose nanofibers on the nanocomposite film properties composed of silk sericin using glycerin as a plasticizer. They concluded that the σ max of
the films increased from 9.47 MPa (without cellulose nanofiber) to a maximum of
28.20 MPa with the addition of 10% cellulose nanofiber, while the E of the films
increased from 320.42 MPa (control) to 805.96 MPa for 20% nanocellulosecontaining films (Kwak et al. 2018). However, ε b values decreased linearly with
respect to the increase in the amount of cellulose (Kwak et al. 2018). Similarly, the
addition of nanocellulose to agar-based composite films increased the σ max and E
values in the films containing up to 3% filler, and the ε b value of composite film
containing 5% nanocellulose was higher than the other cellulose levels (Shankar
and Rhim 2016b). Shankar and Rhim (2016b) also studied the effect of incorporating microcrystalline cellulose at the same levels of nanocellulose, and the σ max , ε b
and E values of these films were comparably lower than nanocellulose-containing
films and even lower than the control film. As an extreme condition, Robles et al.
(2016) studied on the composite films made from cellulose nanofibers (90–100%)
containing chitin nanocrystals between 0–10%. The σ max and E values did not vary
significantly with the increasing amount of cellulose nanofiber, although the highest
ε b (7.57%) value belonged to the 100% cellulose nanofiber film (Robles et al. 2016).
Ilyas et al. (2018) produced a nanocomposite film containing lowest level of cellulose (0–1%) using sugar palm starch and sugar palm nanocellulose. The incorporation of nanocellulose improved the σ max and E values up to a 0.5% content, although
the 1% nanocellulose did not have a similar behavior due to the uneven distribution
and agglomeration of the nanocellulose (Ilyas et al. 2018). In addition, the addition
of sugar palm nanocellulose reduced the ε b values of the films compared to the control sample (Ilyas et al. 2018).
The mechanical properties are also influenced from the minor constituents that
are added for film-forming capacity of nanocellulose-containing composite films.
For example, the addition of gum Arabic to nanocellulose/starch composite
films resulted in higher σ max and ε b values compared to the pure starch and
6 Functional Biobased Composite Polymers for Food Packaging Applications