No, they cannot block 100% of the noise due to their portable design.
To achieve soundproofing, you will require a sealed acoustic barrier. The Noise Reduction Coefficient is largely irrelevant with mobile room dividers because any sound waves that don’t hit the panel will not be absorbed. For a mobile room divider which is not floor to ceiling height there will be space around the divider. Therefore, mobile room dividers can only achieve sound dampening and reduction of noise reverberation. They have gaps by design to give them mobile flexibility.
Your best option for "soundproofing" is a track mounted operable wall. They have high NRC panels, are designed to telescope out in a straight line (and can fold back when not needed), and have a sealed panel joint above, below, between and beside all panels. However, if you're looking for a mobile freestanding divider, please understand it won't be possible to achieve a soundproof barrier as there is a trade off to be made when looking for flexibility, mobility and soundproofing.