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1 Introduction to PVA-Based Bionanocomposite Films
In case of polymer/HNT nanocomposite system, thermal properties may be significantly improved compared to polymer matrices due to the following reasons: (i)
the thermal stability of HNTs is much higher than that of polymer matrices with
initial degradation typically taking place at ~400 °C; (ii) excellent HNT dispersion
in polymer matrices leads to better barrier effect towards mass and heat transport and
(iii) polymer chains and volatile products can enter HNT lumens leading to a delay of
mass transport with the further improvement of thermal stability. Swapna et al. [201]
found that the inclusion of HNTs improved thermal stability of PVA due to the heatbarrier effect of inorganic fillers. However, T g and the degree of crystallinity were
decreased with the inclusion of HNTs, possibly relating to the plasticisation effect of
hydrophilic HNT fillers [201]. Qiu et al. [16] stated that decomposition temperatures
at the weight loss of 30 and 50% appeared to be increased by 3–5 °C for PVA/HNT
nanocomposite films when compared with neat PVA despite no identified change of
T g . This phenomenon mainly depends on uniform dispersion of HNTs within PVA
matrices for better thermal stability. Similarly, other studies have also indicated a
critical role of HNTs in improving thermal properties of various biopolymers such
as PVA [16], PEG [202] and starch [203].
1.7 Summary
The preparation and properties of different bionanocomposites reinforced with
HNTs, OMLS and BCs have been explicitly discussed. Many advantages of
bionanocomposites are summarised as follows:
• Improved mechanical properties of bionanocomposites in solid and melt states as
opposed to those based on conventional composites.
• Significant increase in the thermal stability of bionanocomposites with the addition of nanofillers to work as heat barriers in the formation of char after thermal
degradation.
• Improved biodegradability of some biopolymers with the inclusion of nanofillers.
The above-mentioned property improvements generally occur at a much lower
loading of nanofillers than those of conventional fillers in composite systems.
Therefore, bionanocomposites not only offer far more lightweight products when
compared with conventional composites, but also make a superior contribution to
widespread applications owing to their excellent material characteristics. Despite
numerous studies and research conducted in the past decades, the commercialisation
of bionanocomposites still undergoes enormous challenges encountered in material
development and innovation in order to meet the applications required by the end
users.
1 Introduction to PVA-Based Bionanocomposite Films
In case of polymer/HNT nanocomposite system, thermal properties may be significantly improved compared to polymer matrices due to the following reasons: (i)
the thermal stability of HNTs is much higher than that of polymer matrices with
initial degradation typically taking place at ~400 °C; (ii) excellent HNT dispersion
in polymer matrices leads to better barrier effect towards mass and heat transport and
(iii) polymer chains and volatile products can enter HNT lumens leading to a delay of
mass transport with the further improvement of thermal stability. Swapna et al. [201]
found that the inclusion of HNTs improved thermal stability of PVA due to the heatbarrier effect of inorganic fillers. However, T g and the degree of crystallinity were
decreased with the inclusion of HNTs, possibly relating to the plasticisation effect of
hydrophilic HNT fillers [201]. Qiu et al. [16] stated that decomposition temperatures
at the weight loss of 30 and 50% appeared to be increased by 3–5 °C for PVA/HNT
nanocomposite films when compared with neat PVA despite no identified change of
T g . This phenomenon mainly depends on uniform dispersion of HNTs within PVA
matrices for better thermal stability. Similarly, other studies have also indicated a
critical role of HNTs in improving thermal properties of various biopolymers such
as PVA [16], PEG [202] and starch [203].
1.7 Summary
The preparation and properties of different bionanocomposites reinforced with
HNTs, OMLS and BCs have been explicitly discussed. Many advantages of
bionanocomposites are summarised as follows:
• Improved mechanical properties of bionanocomposites in solid and melt states as
opposed to those based on conventional composites.
• Significant increase in the thermal stability of bionanocomposites with the addition of nanofillers to work as heat barriers in the formation of char after thermal
degradation.
• Improved biodegradability of some biopolymers with the inclusion of nanofillers.
The above-mentioned property improvements generally occur at a much lower
loading of nanofillers than those of conventional fillers in composite systems.
Therefore, bionanocomposites not only offer far more lightweight products when
compared with conventional composites, but also make a superior contribution to
widespread applications owing to their excellent material characteristics. Despite
numerous studies and research conducted in the past decades, the commercialisation
of bionanocomposites still undergoes enormous challenges encountered in material
development and innovation in order to meet the applications required by the end
users.