Acyclic diene metathesis or ADMET is another method that utilizes the olefin metathesis reaction for polymer synthesis. The substrates for ADMET are open-chain alkenes having two double bonds at the ends of a long chain, such as 1,8-nonadiene. Primarily, two equivalents of 1,8-nonadiene react in the presence of Grubbs catalyst to form a dimer and ethylene gas. The formed ethylene gas escapes during the reaction, favoring the product formation. The repetition of these steps leads to the formation of an unsaturated polymer product. The ADMET reaction is highly efficient for polymerization and is used to prepare polymers with molecular weights as high as 80,000 amu.