Effects of amine, amine salt and amide on the behaviour of carbon dioxide absorption into calcium hydroxide suspension to precipitate calcium carbonate

Polymerization properties of polyamide in bottom-up prepared polyamide-calcium carbonate composites

“…The average crystallite sizes of calcite and aragonite calculated by Scherrer's equation were approximately 50 and 30 nm respectively. Although the successive phase transformation from vaterite to aragonite was observed during the precipitation process with HMDA with the same experiment condition . The morphology of calcite was rhombohedron agglomerating with approximately 1–2 µm, and the aragonite was needle‐like (approximately 1.5 µm in length × 50 nm in width) (Fig.…”

“…The mixtures of CaCO 3 and polyamide monomers were prepared by the reaction of Ca(OH) 2 with CO 2 in the aqueous suspensions. According to the previous results of study , the 200 mM of ɛ‐caprolactam and HMDA were added into 500 mL of 20 mM Ca(OH) 2 suspension, respectively, to obtain the fine calcite or aragonite particles. The precipitation of CaCO 3 was carried out through an injection of a mixture of CO 2 and N 2 gases (N 2 :CO 2 = 95:5 by vol) into the aqueous Ca(OH) 2 suspensions kept at 30°C using a water bath, at a flow rate of 1 L/min.…”

“…The pH of the suspensions was monitored during the precipitation process. The experiment conditions were similar to those described previously . When the pH of the suspensions reached the final stable value, the precipitation reaction was stopped and the powdered CaCO 3 was collected by filtration, repeatedly washed, and dried at 60°C for 3 hr.…”

“…Under the precipitation conditions, without organic additives and with organic additives, such as nylon 6‐6 salt and ɛ‐caprolactam, the obtained PCC was calcite possessed different particle sizes depended on the additives and their concentration in the aqueous solutions. Although the needle‐like shape aragonite fine powders were synthesized by the addition of HMDA . The result suggested that the yield of the fine aragonite powders were increased when increased the concentration of HMDA.…”

Rehydration and Textural Properties of Dried Konjac Noodles: Effect of Alkaline and Some Gelling Agents

“…Thus, using alkaline solution showed better cohesiveness values than sodium alginate. It may be possible to use calcium ions (Ca 2+ ) from calcium hydroxide to absorb CO2 and precipitate calcium carbonate (CaCO3) [25]. Thus, the strength of konjac noodle structure may result from Ca 2+ from limewater or calcium hydroxide solution which reacted with CO2 in the environment of the samples to produce crystals of CaCO3 in the noodle matrix to make a strong and elastic gel.…”