Blend composition dependence of the compatibilizing efficiency of graft copolymers for immiscible polymer blends

Abstract

International audienceThis work is concerned with the dependence of the compatibilizing efficiency of graft copolymers on the composition of immiscible polymer blends. A series of graft copolymers of polystyrene (PS) and polyamide 6 (PA6), denoted as PS-g-PA6, with different molecular structures were used as compatibilizers. The PS-g-PA6 was more efficient for the PS/PA6 (80/20) blend than for the PS/PA6 (20/80) one, indicating that a graft copolymer whose backbone and grafts match the matrix and the disperse phase polymers, respectively, has higher compatibilizing efficiency. This is in disagreement with the literature. Moreover, whatever the blend composition, for PS-g-PA6 graft copolymers with the same backbone and the same number of grafts per backbone, the longer the grafts, the higher their compatibilizing and stabilizing efficiency; for a given backbone/graft mass ratio, the longer the grafts and concomitantly the smaller the number of grafts per backbone, the higher the compatibilizing and stabilizing efficiency of the graft copolymer

Tracer‐compatibilizer: Synthesis and applications in polymer blending processes

“…Indeed, PS‐ g ‐PA6‐Ant2 was expected to have much higher miscibility with the PS than PA6 because of its short PA6 grafts. These results are in agreement with the conclusions drawn in the literature [8, 23, 24]. The concept of the tracer‐compatibilizer shown in this article offers a much simpler and more convenient method to construct emulsification curves, to select the most appropriate compatibilizer under real blending conditions and to scale up and optimize the blending process.…”

Compatibilizing efficiency of copolymer precursors for immiscible polymer blends

“…Some authors concluded that the compatibilizing efficiency of tapered diblock copolymers is better than that of the conventional diblock and triblock copolymers 11, 12. Our recent studies have shown that for graft copolymers with the same backbone and the same number of grafts per backbone, the longer the grafts, the higher their compatibilizing and stabilizing efficiency; for a given backbone/graft mass ratio, the longer the grafts and concomitantly the smaller the number of grafts per backbone, the higher the compatibilizing and stabilizing efficiency of the graft copolymer 1, 6, 9. These studies are mainly related to the compatibilizing efficiency of premade copolymers.…”

“…However, the vast majority of polymers are mutually immiscible and thermodynamically unstable, which leads to phase separation and yields materials with poor mechanical properties 1–3. To address this challenge, various kinds of copolymers have been used as compatibilizers in blends to reduce the interfacial tension, promote the dispersion of one phase in another and stabilize resulting morphology 4–6. Especially, block and graft copolymers whose segments are chemically identical to or have affinity with the polymer components as compatibilizers have gained significant research interest in recent decades.…”

Instability of graft copolymers under polymer blending conditions

“…In-situ compatibilization is the prevailing method and the resulting compatibilizer is often a graft copolymer (Kim et al, 1997;Kitayama et al, 2000). The compatibilizing efficiency of a graft copolymer may depend very much on its structure variables such as backbone length, graft length, and graft density (Zhang et al, 2007b(Zhang et al, , 2008b(Zhang et al, , 2010.…”