Check
Wiki Silk, there is a section on properties.
... Silk is one of the strongest natural fibers, but it loses up to 20% of its strength when wet. It has a good moisture regain of 11%. Its elasticity is moderate to poor: if elongated even a small amount, it remains stretched. It can be weakened if exposed to too much sunlight. It may also be attacked by insects, especially if left dirty. ...
While on the subject, check out
Spider silk too. Strength and toughness compared to kevlar...