Effect of Molecular Weights of Poly(acrylic acid) on Crystallization of Calcium Carbonate by the Delayed Addition Method

Abstract

The effect of poly(acrylic acid) (PAA) on the mineralization of CaCO 3 was studied by varying the molecular weights (PAA1.2k, M w ¼ 1200; PAA25k, M w ¼ 25000; PAA250k, M w ¼ 250000) as well as by changing the addition time of the sodium salts of PAA (PAA-Na) to an aqueous solution of calcium carbonate. The precipitation of CaCO 3 was carried out by a double jet method. Stable vaterite crystals were successfully obtained by delaying the addition of all the sodium salts of PAA from 1 to 60 min, and the resulting particles were formed by a spherulitic growth mechanism. The vaterite particles modified with PAA25k-Na and PAA250k-Na showed higher stability than the ones stabilized by PAA1.2k-Na in an aqueous solution. However, in the initial presence of PAA-Na, amorphous calcium carbonate (ACC), vaterite or calcite were induced under various conditions. It is interesting to find that the ACC product induced by PAA1.2k-Na was more stable than that induced by PAA25k-Na in an aqueous solution as well as in a dry state. It was also found that the CaCO 3 particles formed through the nano-aggregation mechanism might be induced by the strong inhibiting effects of PAA-Na, while the spherulitic growth mechanism might be due to the insufficient inhibiting efficiency for the crystallization. These results suggest that the selective interaction of PAA-Na with CaCO 3 at different stages as well as the inhibiting strength varied with the chain lengths of PAANa could play an important role for the controlling of the crystal nucleation and growth during the crystallization process.

Dynamic intratubular biomineralization following root canal obturation with pozzolan‐based mineral trioxide aggregate sealer cement

“…Further, the small particle size would have contributed to induce more stable precursors for guiding an effective diffusion of the ions than the higher molecular weight particles of ProRoot MTA (Huang et al ., ). The mean particle size for white ProRoot MTA is 10 µm, with all particles being smaller than 50 µm (Komabayashi and Spangberg, ).…”

“…However, the tags found in dentinal tubules of GP with Pz-MTA sealer group are the results of material penetration aided by the vertical condensation pressure transmitted via thermoplasticized gutta-percha, and are clearly distinct from such "tag-like structures" in the other groups. Further, the small particle size would have contributed to induce more stable precursors for guiding an effective diffusion of the ions than the higher molecular weight particles of ProRoot MTA (Huang et al, 2008). The mean particle size for white ProRoot MTA is 10 mm, with all particles being smaller than 50 mm (Komabayashi and Spangberg, 2008).…”

A Leaf out of Nature’s Book: Hairy Nanocelluloses for Bioinspired Mineralization

“…Note that while these criteria are necessary, they may not be enough to effectively mimic the biomineralization process, and parameters such as flexibility, conformation, and stereochemistry may play key 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 9 roles. Noticeable examples are the inability of polyacrylic acid (PAA) 53 and polysaccharidebased crystal modifiers (e.g., carboxymethyl cellulose, CMC) 54 The affinity of COO -towards CaCO 3 crystals is well supported in literature. 55 When the ENCC concentration is ~ 0.033 ppm, no significant influence on the CaCO 3 mineralization is observed, and rhombohedral calcite is obtained (Figures 2a-d).…”

Microspheres of calcium carbonate composite regulated by sodium polyacrylates with various ways

“…The higher concentration of PAA in the solution was inclined to the formation of irregular particles of CaCO 3 ; the crystallization of vaterite and aragonite was favored in the presence of PAA at high temperature 17, 33, 34. Also the effects of M w of PAAs and the ratios of [COO − ]/Ca 2+ on the crystallization and polymorph of CaCO 3 as well as the stability of formed CaCO 3 composite have been investigated in a certain extent 35, 36…”