As soon as it appeared on the market, one half century ago, polypropylene (PP) appeared as a promising fibre-forming polymer but with some difficulties in processing due to a lack of control of its viscoelastic properties and in durability due to its low stability to oxidation. These difficulties were progressively resolved in the last decades by a sharper control of synthesis conditions e.g. of stereoregularity and molar mass distribution, and by a better knowledge of oxidation and stabilization mechanisms. These research efforts allowed PP to invade a very wide range of fibre applications, from disposable diapers to geotextiles
