Currently, in the thermoplastic injection industry, there are several processes allowing heat cycling within the mould. Although they have their own characteristics, their purpose is the same. There are many advantages to be taken into consideration whilst injecting hot thermoplastic onto a heated tool, such as : no welding lines, no sink marks, no paint necessary and the possibility to easily inject engineered materials.

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The mechanical properties of poly(lactic acid) (PLA)/polycarbonate (PC) blend were improved considerably by addition of both poly(butylene adipate-co-terephthalate) (PBAT) and dicumyl peroxide (DCP) as a radical coupling agent for PLA and PBAT. In this work, the authors aimed to grasp meltdown properties of PLA/PBAT with/without DCP by (1) clarifying the effect of addition of DCP on the melt viscoelatsic properties of PLA/PBAT, and make this ternary system more suitable by (2) optimizing additive contents and (3) investigating the effect of fabrication processes on mechanical properties and morphologies of the blends. The growth curves of G' and G'' for PLA/PBAT (70/30) (wt/wt) with/without DCP measured by a rheometer suggested that branching and cross-linking structures were formed by hetero-and/or homogeneous radical coupling reactions. The elongation at break of the ternary reactive blend with DCP 0.30 phr (PLA/PBAT/PC blend with DCP) increased up to 160%, which was much better than that with other DCP contents. Moreover, the value of standard deviation for the ternary reactive blend was smaller. Furthermore, PLA/PBAT/PC ternary polymer blends were prepared through a twin-screw extruder with an L/D ratio of 75, and their physical and meltdown properties were investigated. The domain size of the reactive blend with an L/D ratio of 75 was smaller than that of 45, however, the impact strength of the blend with an L/D ratio of 75 decreased with increasing rotation speed of the extruder. Moreover, the MFR of the blend increased with increasing rotation speed of the extruder as well. As the MFR of PC prepared under same condition of blending did not change, so this suggested that PLA/PBAT components of the ternary blends were degraded in higher shear rate. As a result, the impact strength of the ternary blends decreased as well.

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