Poly interface with polystyrene, fracture energy

One might wonder whether it is possible to correlate the interfacial fracture energy of an incompatible polymer pair more precisely to the width of the interface. Such a correlation clearly exists at a qualitative level. For example, polystyrene is substantially less miscible with poly(2-vinyl pyridine) (PVP) than it is with PMMA. This is reflected via equation (4.2.4) in the width of the... 

Figure 7.4. Fracture energies of interfaces reinforced by block copolymers as a function of the effective areal density of chains crossing the interface. Triangles and squares are for polystyrene/poly(2-vinyl pyridine) interfaces reinforced with styrene-2-vinyl pyridine block copolymers (Creton et al. 1992) circles are for poly(xylenyl etherypoly(methyl methacrylate) interfaces reinforced with styrene-methyl methacrylate block copolymers (Brown 1991a, b). After Creton et al. (1992).

Figure 7.9. Interfacial reinforcement of a polystyrene/poly(vinyl pyridine) interface by a high relative molecular mass deuterated styrene-vinyl pyridine block copolymer, with degrees of polymerisation of each block 800 and 870, respectively. Circles (right-hand axis) show the measured interfacial fracture energy as a function of the areal chain density of the block copolymer 2, whereas crosses show the fraction of dPS found on the polystyrene side of the interface after fiacture. The discontinuity in the curves at 2 = 0.03 nm is believed to reflect a transition from failure by chain scission to failure by crazing. After Kramer et al. (1994).

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