Reactive blending of polyamide 6,6 and vectra A, 2

Abstract

In a previous paper Nylon 6,6/Vectra A blends have been prepared and investigated; in particular, our attention has been focused on Nylon 6,6 modifications due to interchange reactions that occur in the melt, as a function of mixing conditions and blend compositions, and improve the compatibility of the blend. The results indicated that only a small amount of copolymeric species form because of the low reaction kinetics and unfavorable physical and rheological aspects. In order to overcome these limits, a further research on Nylon 6,6/Vectra A blends has been carried out to test the role of modified processing conditions in the presence of a reactive additive able to improve the extent of reactions between blend components and the melt viscosity of the polyamide matrix. The potential of a Nylon 6,6 sample with predominant NH2 end‐groups on its reactive blending with Vectra with or without the reactive third component has been investigated. Nylon and Vectra, combined in weight ratios between 90/10 and 50/50, were subjected to reactive blending with different methods (a laboratory Pyrex reactor, a single‐screw extruder, and a Brabender mixer). Neat Nylon samples have been also investigated as reference materials. Thermal and morphological analyses were carried out on the blends. The soluble Nylon 6,6‐rich fraction of each blend was separated from the insoluble Vectra‐rich one, and both were used for spectroscopic characterizations; mixed Nylon‐Vectra copolymers have been recognized in both the soluble and insoluble fractions of the blends.

Morphology and Viscoelastic Behaviour of a Silica Filled Styrene/Butadiene Random Copolymer

“…In fact, the evaluation of morphometric parameters can provide quantitative and direct information on the filler dispersion and on the structure of the aggregates. [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] Furthermore, as the tensile and viscoelastic behaviour of composite materials is related to filler-filler and fillerelastomer interactions, mechanical and dynamicmechanical properties are generally used to study the rubber reinforcement. [1,[3][4][5]7,[10][11][12][18][19][20][21][22]25,[36][37][38][43][44][45][46][47][48][49][50][51][52][53]…”

“…[17,[39][40][41][42][43] To deepen the knowledge and attain a quantitative evaluation of the effect of surface modification on silica dispersion and rubber reinforcement, in the present contribution we report the results of a morphometric characterisation and of the dynamic-mechanical properties of compounds based on a styrene-butadiene random copolymer (SBR) loaded with different amounts of silica, either untreated or treated with TESPT and/or octadecyltriethoxysilane (ODTES). To this purpose, automated image analysis was performed on digitalised TEM micrographs and several morphometric descriptors -area (A), perimeter (P) and A/P ratio -were evaluated.…”

“…[40] The fundamental filtering procedure of the micrographs makes it possible to select the grey tone of the single particle of filler (the tone next to that attributed to the polymer matrix) and to count and measure all the aggregates by using different morphometric descriptors; [39][40][41][42] among these, projected area (A), perimeter (P) and area-perimeter ratio (A/P) were selected.…”

Enhanced wear performance of nylon 6/organoclay nanocomposite by blending with a thermotropic liquid crystalline polymer

“…In the core section of hybrid nanocomposite H1, the VA phase exists as droptlets, but not in smooth spherical shape as commonly seen in immiscible polymer blends. Most probably, such unique morphology was caused by the possible interchange reaction between nylon and VA [34]. For the core layer in H2 system, the VA phase still shows the fibril characteristic ( Fig.…”

In situ compatibilization of a polyetherimide and a thermotropic polyester using an epoxy resin

“…Moreover, previous works demonstrated that morphology and mechanical properties of in situ composites are affected by poor adhesion between the matrix and the TLCP [17,23]. Therefore, several routes were followed to improve compatibility, by modifying the TLCP fibre geometry, by chemical grafting of flexible polymer onto the TLCP fibre surface, by interchain reactions between the liquid-crystalline and the thermoplastic components, and by adding a second liquid-crystalline polymer partially miscible with both the reinforcing TLCP and the matrix [14,[24][25][26][27][28].…”