64
3 PVA/BC Bionancomposite Films with Particle Size Effect
2θ (degree)
2θ (degree)
(a)
(b)
Fig. 3.6 XRD patterns of a PVA/NBC bionanocomposites [30] and b PVA/MBC bionanocomposites [27]
bionanocomposites, as seen in Fig. 3.6b, demonstrate a peak shift to smaller diffraction angles. Moreover, XRD patterns of bionanocomposites only display PVA peaks,
while the diffraction peaks of MBCs and NBCs disappear. Such a finding indicates
that PVA molecules can cover nanoparticles and thus make active bonding interactions inside these pores because BC pores possess ‘mechanical anchoring’ mechanism [9] when interacting with PVA molecular chains. This phenomenon means
that a mechanical interlocking phenomenon takes place due to the existence of PVA
molecular chains inside BC surfaces [9]. Similar results have also been observed in
PVA/5 wt% GO nanocomposites [31].
3.3.2 Mechanical Properties
As illustrated in Fig. 3.7a and Table 3.2, tensile moduli of PVA bionanocomposites
reinforced with NBCs and MBCs increase significantly in a monotonic manner with
increasing the BC content. The maximum moduli of bionanocomposites taking place
at 4.63 and 4.16 GPa have been achieved with 10 wt% NBC and MBC inclusions,
respectively, which are equivalent to modulus increases by 123 and 100%, as opposed
to that of neat PVA at 2.08 GPa.
On the other hand, tensile strengths of PVA/NBC bionanocomposites and
PVA/MBC bionanocomposites demonstrate initial enhancements up to 110 and 72%
when the BC content increases from 0 to 3 wt%. Beyond 3 wt% BC inclusions,
tensile strengths of both bionanocomposites tend to decline until they reach the
lowest strength levels of 96.34 and 80.69 MPa, respectively, at the BC content of 10
wt%.