The relationship between the impact strength and
the filled quantity of nucleating agent is shown in Fig.
4. A maximum impact strength exists at the 0.4 wt.%-
filled quantity of nucleating agent, corresponding to the
changing regularity of the crystalline morphology. While
the filled quantity of the nucleating agent was below 0.4
wt.%, with the rise of the filled quantity, the spherulite
size tended to decrease. The fineness of the crystal
grain must, therefore, be beneficial to impact strength.
Furthermore, the nucleating agent impelled the degree
of orientation of the polymer and improved the crystallization
rate, retarding the relaxation of the cooling
process of the polymeric melt. This will produce a more
tied-molecule structure among the intra- and interspherulite
to improve the molecular entanglement
between the crystal grain. Therefore, the boundary
strength between spherulite increased, thus it will be beneficial to the improvement of the impact strength of
the materials