The effect of physical interactions on melt-phase homogenization of mixtures of poly(m-xylene adipamide) with aliphatic polyamides induced by interchange reactions

Commercial Polymer Blends

“…PA-MXD6, produced by Mitsuibishi Gas Chemical Co, is a high oxygen barrier resin particularly useful in multilayer coextrusions (Harada 1988) and blends. In the blends of MXD6 with aliphatic polyamides, interchange reactions may play a role during melt-mixing, particularly at long residence time (Takeda and Paul 1992). However, under the normal commercial melt compounding and extrusion throughput rates, interchange reactions are minimal and good miscible blend products can be obtained.…”

Interchange Reactions in Condensation Polymers and Their Analysis by NMR Spectroscopy

“…It is known that at temperatures of about 250°C, copolymer formation occurs by amide exchange in a melt of two polyamides [176,180]. Some attempts have been made to characterise the extent of interchange reactions in mixtures of poly(m-xylene adipamide) and Nylon 6 [181] and also in mixtures of Nylon-z, y polymers [182], where x indicates the number of carbon atoms separating the nitrogen atoms in the diamine and y the number of straight-chain carbon atoms in the dibasic acid. However, these analyses by NMR are not sufficiently convincing.…”

Reactive Melt Processing of Aliphatic/Aromatic Polyamide Blends: Effect on Molecular Structure, Semicrystalline Morphology, and Thermal Properties

“…Moreover, since the transreacted chains facilitate compatibilisation, this will also accelerate the reaction of the non-reacted chains, thus enhancing compatibilisation to an even larger extent. The achievement of improved compatibility between the blend components using transreaction processes has already been studied extensively for polyester, polycarbonate [24-261 and polyamide [7,8,27] blends. Hereby, it is often observed that the two separate glass transition temperatures of the immiscible blend components merge systematically into one glass transition temperature with increasing reaction time.…”

“…Other examples of studies where NMR has been used as a method of characterisation are the interchange reactions in polyarylate (PAr)/poly(butylene terephthalate) (PBT) blends [53,54] and the sequence randomisation of wholly aromatic copolyesters [55]. Regarding polyamide blends, some attempts have been made in the literature to characterise the extent of interchange reactions in mixtures of poly(m-xylene adipamide) and polyamide 6 [7] and also in mixtures of nylon-2, y polymers where z indicates the number of carbon atoms separating the nitrogen atoms in the diamine, and y the number of straight-chain carbon atoms in the dibasic acid [8]. However, these analyses by means of 'H NMR are not sufficiently convincing.…”

“…By controlling the interchange reactions in these miscible blend systems during the melt-mixing process, it is possible to design tailored block or random copolymers with useful properties. In immiscible polycondensate blends, the control of the interchange reactions occurring at the interface between the phases allows the preparation of blend systems with a finer phase dispersion than in the corresponding physical mixtures; this is due to self-compatibilisation [7,8].…”