Functional clays as reinforcement of nitrile latex films

Latex films with novel properties were prepared by latex compounding. Different proportion of a natural sodic montmorillonite (CastiG) and CastiG modified with cetylpyridinium chloride were incorporated into the latex matrix. SAXS and XRD tests were performed to evaluate the clay/polymer interaction, determining, in all cases, the intercalation of the polymer chains within the laminar structure of the clay, which improves the nanocomposite properties.

Increases in tensile strength

Increases in tensile strength are observed as the clay proportion increases, except for samples containing 5 phr of both types of clays. Likewise, modulus at 100% elongation increases since the clays stiffen the NBR matrix. This effect also occurs with the increase of the maximum and minimum torque from rheometry tests, leading to a higher crosslinking density when the CPA clay is incorporated. Regarding the kinetic reaction, the presence of clays induces a significant decrease in the vulcanisation times of the nanocomposites with respect to that of the non-reinforced matrix. Reinforced films also present a reduction of the water vapor permeability (WVP), as the presence of clays increases the tortuosity of the path for the diffusion of molecules.

Antimicrobial capacity of NBR films

Finally, the antimicrobial capacity of NBR films was evaluated against two types of bacteria and fungi. In general, the reinforced NBR presents a greater resistance to Escherichia coli, showing no modification in the intrinsic antibacterial capacity of the NBR when exposed to fungi.

The study is published in: Progress in Organic Coatings Volume 129, April 2019, Pages 271-277.

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The European Coatings Seminar Water-borne coatings will give participants all the necessary knowledge to start working on their own formulations. The seminar will take place on 22 May 2019 in Amsterdam.