Comparing the Major Synthetic Rope Materials. When deciding what rope best suits your need, it is often a matter of compromise. There are 5 major synthetic ropes in use for boat and marine applications. Polypropylene, Polyester, Nylon, UHMWPE (Ultra High Molecular Weight Polyethylene) and Aramids (Kevlar®, Technora®, Vectran®, etc). Each has outstanding virtues and each has faults.