Polypropylene nonwovens were modified by using layer-by-layer method. This is quite new method, and relatively rarely used for textile products. As a modifiers were used different polyelectrolytes such as: PAA – poly(acrylic acid), PDMAEMA – poly(N,N-dimethylaminoethylmethacrylate), PAH - poly(allylamine hydrochloride). Polypropylene nonwovens modified by layer-by-layer method are the subject of controlled thermal degradation procedure. The whole sample weight consist mostly of the main object – weight of external, deposited layers is in comparison to main object, very small. That means that the thermogravimetric curve contains weight loss associated with thermal degradation of the polypropylene material. All changes in TG curve are connected with the influence of deposited layers onto the character of PP degradation.