Polymers, functional oxazoline reactive groups

Neither of the two base polymers (A and B) contain reactive groups. Most hydrocarbon polymers, such as polyethylene PE, PP, PS and copolymers thereof, are in this situation. In such cases, different compatibilization methods can be envisioned. The first one is to add two reactive polymers (C and D) which are mutually reactive and are miscible with A and B, respectively. The resulting copolymer will be of type C-D. The second one is to hmctionalize polymers A and B with different functional groups, which are mutually reactive. Take PE/PS blends as an example. When PE is functionalized with a carboxylic group and PS with an oxazoline group, they will be able to react with each other and form a desired compatibilizer [6]. 

Variously substituted oxazoline monomers, 2-ethyl, 2-n-pro-pyl, and 2-vinyl oxazoline monomers for HA, were newly prepared and polymerized with HAase catalysis. The reactions proceeded with total control of regioselectivity and stereochemistry, to afford the corresponding HA and Ch derivatives (unnatural polysaccharides) possessing N-propionyl, N-butyryl, and N-acryloyl group in every hexosamine unit (Scheme 40). Similarly, Ch derivatives were also achieved. The resulting N-acryloyl HA and Ch are functional polymers having a reactive vinyl group. 

In this way, the functionalization of one component in immiscible polymer blends has attracted great interest in terms of the compatibilization.For example, Lambla and his coworkers reported a series of works on the in situ compatibilization of immiscible polymer blends by one-step reactive extm-sion. ° They described the chemical reactions related to compatibiUzing polymer blends, especially for the PBT/polypropylene (PP) blend system. They stressed that the monomers used for functionalizing PP, such as acrylic acid (ACID), MAH, GMA, and oxazoline, are potentially reactive towards the carboxylic acid and/or hydroxyl groups at the chain ends of the PBT and are melt grafted onto the PP by free-radical reactions. 

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