Preparation of PP-g-PA6 copolymers through reactive blending

Excerpt

Block or graft copolymers have gained much interests recently, not only because of their general application as compatibilizers in blends with thermodynamically immiscible polymer pairs [1], but also of many special and important characteristics of themselves, such as the formation of self assembly morphologies, which can be used for drug delivery, nanoreactor and molecular templating, etc. [2, 3]. In general, copolymers can be prepared by ionic polymerization [4], controlled radical polymerization [5] and some other special polymerization methods [6, 7]. However, for some specific polymer pairs, such as polypropylene (PP) and polyamide 6 (PA6), it is still a challenge to prepare premade PP-g-PA6 copolymer. Although, maleic anhydride can react with the end amino group of PA6 and in situ forming PP-g-PA6 graft copolymer at the phase interface when maleic anhydride modified PP (PP-g-MAH) is used as an interfacial compatibilizer in PP and PA6 blends [8, 9], the amount of such copolymer is too small to be extracted out because of the relatively low grafting degree of MAH on PP. Preparing such kind of copolymers is still unpractical so far. Recently, Leibler et al. [10] successfully increased the MAH content by preparing the poly (ethylene-ethylacrylate-MAH) copolymer (PE-1) before blending with PA6. They have extracted the PE-1-g-PA6 copolymer out from the blending system in their work. In this communication, we will report another novel exploration of preparing PP-g-PA6 copolymers through reactive blending. …