Although Ziegler-Natta (Z-N) polyolefins have been widely used as raw materials to produce pharmaceutical or food packaging, the migration of acid scavengers, an additive usually introduced in Z-N polyolefins, from the packaging to its contents has not been reported. In this work, the migration of the two most used acid scavengers, calcium stearate (CaSt 2 ) and zinc stearate (ZnSt 2 ), from a Z-N polypropylene random copolymer (PPR) into water during autoclaving at 121 °C were comparatively investigated. It was found that, for PPR plates containing 0.1 wt% CaSt 2 or ZnSt 2 (PPR-0.1CaSt 2 , PPR-0.1ZnSt 2 , respectively), the concentration of migrated calcium ion into water increased with autoclaving time, while that of zinc ion was much lower at same treatment durations and did not show a significant increase with treatment time. Interestingly, after removing all plates and acidification treatment, a considerable amount of stearic acid was detected in sterilized water for PPR-0.1ZnSt 2 , but no such significant stearic acid was detected in sterilized water for PPR-0.1CaSt 2 . Based on the structural evolution of the two soaps upon heating, possible mechanisms for the different migration behavior of CaSt 2 and ZnSt 2 from PPR into water during autoclaving treatment were proposed. Our results suggest that the migration issue of acid scavengers is worthy of attention in pharmaceutical packaging materials produced from Z-N polyolefins.
Nano-sized calcium carbonate , as a multifunctional material, is widely used in various industrial fields. The morphology, particle size, surface property of CaCO 3 particles have great impact on the application effect. This study presents an energy-saving and efficient approach to controllably prepare CaCO 3 nanoparticles and conduct surface modification simultaneously. Ca(OH) 2 /CO 2 carbonation method was adopted to prepare CaCO 3 nanoparticles using a membrane dispersion microreactor in the presence of calcium stearate (CaSt 2 ) surfactant . The effects of gas and liquid flow rates , temperature and the dosage of surfactant were systematically investigated. The effect of surface modification was evaluated by contact angle and active ratio. The as-prepared hydrophobic CaCO 3 nanoparticles were of good dispersity, with an average particle size of 34 nm, a specific surface area of above 30 m 2 /g and a contact angle of 107.8°. In this work, the effect of surfactant on the carbonation reaction was greatly diminished by adding CaSt 2 surfactant to a portion of Ca(OH) 2 slurry. Additionally, the modification process was carried out without organic solvents and high temperature. As compared to post-modification method, the in-situ modification process is of significant practical importance because of high production efficiency, excellent process stability, and high product quality.
危险品化学品经营许可证（带存储）