The crystallization behavior of poly(lactic acid) with different types of nucleating agents

The effects of six nucleating agents (NAs), i.e., orotic acid (OA), potassium salt of 3,5-bis(methoxycarbonyl)benzenesulfonate (LAK-301), substituted-aryl phosphate salts (TMP-5), talc (TALC), N' 1 , N' 6 -dibenzoyladipohydrazide (TMC-306) and N 1 , N 1′ -(ethane-1,2-diyl)bis( N 2 -phenyloxalamide) (OXA), on the crystallization behavior of poly(lactic acid) (PLA) were compared by DSC . Under the same dosing of 0.5   wt%, the nucleation effect of the NAs for PLA declines in the order of TMC-306   ≈   OXA   >   TALC   ≫   TMP-5   ≈   LAK-301   ≈   OA. The nucleation efficiency (NE) of TMC-306 and OXA is around 50%, which is almost 2 times of the NE of TALC. In the best case of the PLA/TMC-0.5% sample, the half-time of crystallization decreases from 30   s to 9   s with decreasing the crystallization temperature from 120   °C to 100   °C, which is of great significance to the fast production of highly crystallized PLA materials. As high-efficient NAs, TMC-306 and OXA are able to accelerate the crystallization rate of PLA even upon fast cooling at 50   °C/min, while make no difference on PLA crystal form, as identified by WAXD . DMA analysis shows that the storage modulus of PLA is significantly improved by TMC-306 and OXA.