**3. Polyolefins' "Golden age"**

Nowadays, polyethylene and polypropylene, as the most popular, widespread, and predominantly produced commodity polymers, account for approximately 32 and 27% of the global polymer market, with an annual growth rate of 4.0% and 5.3% within the forecast period of 2019 to 2027, respectively [3]. With a global market value of \$300 billion and volume of 180 million tons they play an important role in our daily life [4].

The "Golden age" of polyolefins started with the seminal discovery of the Nobel Prize winners, Prof. Karl Ziegler and Prof. Giulio Natta, which was followed by finding the magical role of methyl aluminoxane in the activation of single-site transition metal catalysts, by Prof. Walter Kaminsky and Prof. Hansjörg Sinn. Then, the late transition metal catalysts bearing α-diamine ligands were introduced by Prof. Maurice Brookhart. These catalysts benefited by their exceptionally high activity, besides high tolerance toward heteroatom-containing moieties, which genuinely elevates polyolefins value to a higher level than the corresponding traditional grades [5–7].

Standing on the shoulders of the giants, the past 70 years of polyolefins technology progress has been summed up in the discovery of new catalysts accompanied with the development of new industrial polymerization processes [8, 9]. As lowcost thermoplastics, polyolefins gain the attention of researchers as an abundant platform for the production of specialty and functional polyolefins [10, 11]. The worldwide interest in specialty polyolefins and research outputs by regions over the last two decades is presented in **Figure 3**.
