Recent research finding
No.61 Mechanism of Deodorizing Effect of MCT-βCD finished Textile on Ammonia.

日本語のページへ

Background

Recently, developments of functional fibers with cold or warm sensing, deodorant effect, water-absorbing and quick-drying, antimicrobial property and antistatic property are very active depending on the demand increase of functional clothes make us comfortable.

Monochlorotriazinyl-β-cyclodextrin (MCT-β-CD) is a reactive cyclodextrin. MCT-β-CD finished textile shows various functions like deodorization and fragrance release. Previously, we found deodorizing effect of MCT-β-CD finished textile on ammonia after washing the textile. However its deodorization mechanism on ammonia was not fully understood.
In this study, we focused acidity of MCT-βCD to defining the mechanism of the deodorant effect against ammonia.

Grafting of MCT-βCD onto cotton.

Fig 1 Washing effect of MCT-βCD finished cotton for reducing of ammonia odor.

Effective deodorization of ammonia was observed by MCT-βCD finished cotton with washing.

It is well known that aqueous ammonia can not be included in hydrophobic cyclodextrin cavity.

We supposed that MCT moiety of MCT-βCD would be relate to deodorizing effect of MCT-βCD on ammonia.

In this study, acidity of MCT-βCD finished onto cotton was explored.

Experiment

By deactivation of MCT-βCD, chloride groups on MCT were converted into hydroxyl groups.
The pKa value of deactivated MCT-βCD was determined with pH dependency of its absorption spectrum.

[Deactivated MCT-βCD] = 0.006% in 100 mM NaClaq at r.t..
The pH of the solution was adjusted by the addition of HCl and NaOH.

Result Fig 2 Acidity of MCT-βCD

Deactivated MCT-βCD was confirmed as acid with pKa=5.5.

Conclusions

  • Deodorizing effect of MCT-βCD finished textile on ammonia was increased after washing the textile.
  • Acidic hydroxyl group of MCT moiety of MCT-βCD could be a potent deodorant site for ammonia odor by neutralization reaction.