**5. Challenges in the commercialization of functional polyolefins**

Since the early 2000s, the synthesis of functional polyolefins with complex architectures faced tremendous progress thanks to the development of novel insertion polymerization catalysts enabling the synthesis of polyolefins with highly controlled molecular weight, chemical composition distribution, and topology. The precise synthesis of functional polyolefins opens up new windows toward the development of engineering grades based on structure–function relationships [10].

Undoubtedly, catalytic polymerization will stand at the core of functional polyolefin production. However, the remaining related challenges are as below;


*Extending Alkenes' Value Chain to Functionalized Polyolefins DOI: http://dx.doi.org/10.5772/intechopen.99078*

Although random functional polyolefins are obtained by applying minimum changes compared to their corresponding homo-polyolefins, they offer drastically different chemical, physical, and surface properties. Therefore, random functional polyolefins are excellent candidates for the replacement of engineering thermoplastics, opening new windows toward the progression of new engineering polyolefins. However, despite the recent developments in the synthesis of such functional polyolefins, there are still several challenges in their production include;


As a solution, the design of new catalysts capable of producing high polar comonomer content functional polyolefins seems to gain more potential in the future. However, despite the tremendous developments in highly effective olefin (co)-polymerization catalysts, only a few of these catalysts have found general applications in industrial polyolefin processes. There are a number of parameters that need to be evaluated. The parameters are catalyst activity and kinetics, range of products with a specific MW and MWD, morphology, branching density and comonomer incorporation homogeneity, tolerance toward polar monomers in the production of functional olefin copolymers as well as polymerization process economics and environmental issues [4, 11].

Also, chain-end functionalized polyolefins synthesized via chain-transfer reactions taking advantage of almost quantitative incorporation of the functional groups at the chain ends. This class of functional polyolefins is a superior starting point for the grafting from or block copolymer synthesis, where the functional fragments are created by another reaction mechanism successively. Furthermore, the complexity in controlling the microstructure and composition of functional copolymers encouraged the researchers toward the copolymerization of ethylene with dormant reactive comonomers. The dormant moiety transformed to functional groups through post-functionalization approaches or to initiators for graft-from polymerization of polar monomers [5]. The other approach comprises the precise synthesis of random functional

polyolefins through metathesis polymerization.

Moreover, different synthetic pathways, such as functionalized carbenes as alternatives for the synthesis of functional polar monomers, are constantly developing [11].

• Last but not least is related to the development of functional polypropylenes. The lower reactivity of propylene compared to ethylene makes the production of functional propylene copolymers much more difficult than ethylene copolymers [72].
