Creating new and high-performace materials starting from polymeric waste is a challenging task for any scientist. Plastics are present in almost every sector of our life. But, they are also a source of a great amount of waste that contaminates the environment. Recycling plastics is an important tool in solving environmental problems. Blends from polymer waste have received a lot of attention in recent years in an attempt to obtain new materials with tailored properties. One of the most promising directions is their modification during synthesis. A wide range of approaches is available, but the most well-known and used is copolymerization, including block copolymerization. Block copolymers have not intermediate properties, but they combine characteristics of the initial polymers. This is the reason why this method is used to synthetize new macromolecular compounds with designed properties, even starting from polymeric waste. The purpose of this paper is to obtain new block copolymers starting from a dienic rubber (macrodiisocyanate rubber MDIR) having molecular mass Mn=3500±200 and a -NCO final groups content of 2,2% and an aliphatic statistic copolyamide (coPA 6/6.6/6.10) with molecular weight Mn = 2600±200, waste resulted from exdruding and granulating operations. Two types of block copolymers were obtained, (AB)n and ABA, where block A is coPA and block B is MDIR. Their structures were controlled by the molar ratio of blocks and confirmed by IR and NMR spectroscopy.