The tan d, which is associated with the dampening effect or energy
lost as a heat due interfacial interactions. The theoretical decrease in the tan d of talc filled and hybrid composite should be the
same as percentage of loading in the composite as the energy loss
is mainly associated to the dampening from the viscous component
of the thermoplastic and not from the rigid filler particles.
Fig. 5, tan d decreases in case of a hybrid composite by 44% but
in case of only talc filled PHBV no decrement in its value was observed.
The increase in the Tg of talc filled composite was confirmed
by the shifting of the tan d peak towards the higher
temperature. No decrease in the tan d value along with higher Tg
specifies the restrictions imposed by the surface of talc particles
to the freedom of rotation of the chain segment in the amorphous
phase of matrix as a result of interfacial interaction between the
talc and PHBV. The additional dampening effect was due to the
agglomerated talc particle–particle slippages or friction. The interfacial
interaction between the PHBV molecules and the talc surface
may have lead to higher energy losses due to the increased polymer
particle friction thus resulting in increased dampening effect.
Lower dampening in case of hybrid particle was due to the additional
stiffer wood fibers than the matrix.