Subject RAFT polymerization

RAFT polymerization has emerged as one of the most important methods for imparting living characteristics to radical polymerization. RAFT has been shown to be robust and has applicability to the majority of monomers that are subject to radical polymerization. However, selection of the RAFT agent for the monomers to be polymerized and the choice of reaction conditions are crucial for success. With these provisos, RAFT polymerization can be used in the synthesis of well-defined homo-, gradient, diblock and triblock polymers as well as more complex architectures which include higher order blocks, stars and polymer brushes. 

The grafting through approach involves copolymerization of macromonomers. NMP, ATRP and RAFT have each been used in this context. The polymerizations are subject to the same constraints as conventional radical polymerizations that involve macromonomers (Section 7.6.5). However, living radical copolymerization offers greater product uniformity and the possibility of blocks, gradients and other architectures. 

As mentioned, polymer hybrids based on POs are effective as a compati-bilizer between the olefinic materials and polar ones. Furthermore, some polymer hybrids, such as PP-g-PMMA, etc., show good mechanical strength as polymer materials. On the other hand, surface modification of the molded polymer is one of the most attractive methods to let polyolefin materials functionalize. In this sense, surface polymerization of functional monomers on polyolefins is an important subject for polyolefin hybrids. As previously referred to, the growth of PS on PP via the RAFT process has been reported [92]. 

Although only narrow-disperse thiolactone-containing copolymers could be obtained, it has been demonstrated that thiolactones are compatible with radical polymerization conditions, using two different techniques (RAFT and NMP). Consequently, these poly(thiolactones) can be subjected to site-specific double PPM (vide infra). 

---