Complex sentence: Synthetic fibers are stronger and more uniform but can't absorb much lubricant, natural fibers can absorb up to 15% of their weight in lubricant and so protect the inner wires much better from corrosion than synthetic fibers do.
Split into simpler sentences: Synthetic fibers are stronger and more uniform but can't absorb much lubricant. Natural fibers can absorb up to 15% of their weight in lubricant and so protect the inner wires much better from corrosion than synthetic fibers do.