High-performance polyamides with engineered disorder

Abstract

The extraordinary property profiles of many biological materials derive from their hierarchical structure and control of order and disorder at different length scales. Application of these concepts to the design...

Thermoplastic Toughening of a Semiaromatic Polyamide with an Amino-telechelic Polyethylene

“…This in turn implied the presence of PA-PE block copolymers with a minimum of two blocks at the interfaces, and a strong likelihood of multiblock copolymer formation, given rapid transamidation at the chosen extrusion temperature . Under these conditions, given that the initial molecular weights of both the PA6TI and the PE were well above their respective entanglement molecular weights, , and that long-range chain mobility is severely limited in solid polymers, reactive compatibilization should lead to strongly anchored, covalent bonding across the matrix–particle interface. − …”

“…This in turn implied the presence of PA-PE block copolymers with a minimum of two blocks at the interfaces, and a strong likelihood of multiblock copolymer formation, given rapid transamidation at the chosen extrusion temperature. 65 Under these conditions, given that the initial molecular weights of both the PA6TI and the PE were well above their respective entanglement molecular weights, 59,64 and that longrange chain mobility is severely limited in solid polymers, reactive compatibilization should lead to strongly anchored, covalent bonding across the matrix−particle interface. 54−56 To complement these results, we performed X-ray photoelectron spectroscopy (XPS) experiments on specimens of PA6TI covered with a layer of aminopropyl-terminated poly(dimethylsiloxane) (PDMS(NH 2 ) 2 ) or trimethylsiloxy- 1b) showed there to be significantly more PDMS attached to the PA6TI surface after heating in the presence of PDMS(NH 2 ) 2 than in the absence of heating or in the control experiments with PDMS(TMS) 2 , which gave similar spectra to the untreated PA6TI surface after heating.…”

“…An increase in the viscosity of an immiscible polymer blend is generally observed when a compatibilization reaction takes place . In the present case, we envisage this compatibilization to take place via polycondensation of the amine end groups of PE­(NH 2 ) 2 with remaining free carboxylic acid termini of PA6TI, and via transamidation reactions by amidolysis, acidolysis, and aminolysis reactions, which we have recently shown to proceed particularly effectively and rapidly in compatible blends of aliphatic polyamides with PA6TI extruded under similar conditions to those considered here. , The consistently higher torques measured for the PA6TI/PE­(NH 2 ) 2 blends compared with the corresponding PA6TI/PE blends over the whole of the 20 min mixing time (Figure a) suggested effective reactive compatibilization of the former. This in turn implied the presence of PA-PE block copolymers with a minimum of two blocks at the interfaces, and a strong likelihood of multiblock copolymer formation, given rapid transamidation at the chosen extrusion temperature .…”