Braided polypropylene rope has good strength - it isn't as strong as nylon or polyester, but is much stronger than manila. It’s easy to splice and has excellent chemical resistance.
On the other hand, it has poor resistance to sunlight, so is not suitable for extended outdoor use, especially where safety is involved.
Diamond braided polypropylene (hollow braid) is used as light duty pulling rope by electrical and outside plant contractors. Caution must be taken that it is not pulled too fast, because the rope can soften, stick, and even begin to melt from frictional heat.
Polypropylene has better dielectric properties than most ropes, so it is used for throw line and hot line rope by tree trimmers, utility workers, and others who work near electrical wires.
Hollow braid is a good tree guy line, and because it floats is used as swimming pool lane marker rope.
Braided polypropylene rope is available in a lot of colors and color combinations, so is good as a visual barrier where color indicates certain conditions, such as yellow/magenta for nuclear areas. And solid yellow color hollow braid is frequently used as a crowd control barrier at golf courses and for temporary events such as marathons and other races.
Fence contractors use black 3/16" or 1/4" hollow braid to tie windscreen to chain link around tennis courts.
Polyethylene is, like polypropylene, a polyolefin. It is a little heavier, not quite as strong, and has a slick surface. It does not have 'memory', which means if it is stretched, it does not return to its original length.
Polyethylene braided rope and twine are used to make netting, and 1/8" diamond and solid braided polyethylene are used as sensor line to guide concrete curb and gutter machines.