Kinetic and thermodynamic parameters guiding the localization of regioselectively modified kaolin platelets into a PS/PA6 co-continuous blend

Abstract

This article highlights the role of kinetic and thermodynamic parameters on the localization of modified kaolin platelets into a high interfacial tension co-continuous PS/PA6 blend after extrusion, injection molding and annealing. Three kinds of copolymers were synthesized and grafted on kaolin: poly(styrene-co-(methacryloyloxy)methyl phosphonic acid) copolymer (P(S-co-MAPC 1 (OH) 2)), polystyrene terminated 3-(mercaptopropyl)triethoxysilane, (ETS-PS) and poly (styrene-co-3-methacryloxypropyltrimethoxysilane) copolymer, (P(S-co-MPS)). Those copolymers were distinguished by (1) the nature of their functional groups (phosphonic acid that reacts only with aluminol groups or alkoxysilane that reacts with both silanol and aluminol groups), (2) the amount of functional groups and (3) their molecular weights. After functionalization the kaolin samples (K1, K2 and K3, respectively) were analyzed by FTIR, TGA and Py-GC/MS to evaluate the grafting. It was shown that P(S-co-MAPC 1 (OH) 2) and P(S-co-MPS) copolymers grafted on kaolin led to highly anisotropic K1 and K3 kaolin platelets, respectively. Then, 50/50/5 PS/PA6/K i samples (i ¼ 0 to 3) were processed as follows: (1) kaolin platelets were dispersed (via solvent cast) into the PS phase. Then, (2) PS þ kaolin were melt mixed by microcompounder with PA6, then (3) the PS/PA6/K i were injection molded into disks and finally (4) they were annealed (via dynamic or quiescent annealing). Thanks to the high shear rate and longtime of mixing during extrusion (microcompounder), all the kaolin platelets (unmodified K, K1, K2 and K3) crossed the interface and were localized in the PA6 phase. All K i kaolin stayed in the PA6 phase during injection. However, after annealing (quiescent or dynamic), the localization of the nanoplatelets was guided by thermodynamic parameters, and SEM analysis revealed the segregation of K1 and K3 kaolin platelets at the polymers interface, with a high tendency to impede polymer phases coalescence. Hence, modified K1 and K3 kaolin are promising compatibilizing agents for a cocontinuous PS/PA6 blend.

Increased Continuity of the PA6 Phase from the PS Matrix Induced by Migrating Janus Particles and Its Application in Thermal Conductivity

“…Previous research found that in compatible blends, the cocontinuous morphology is formed by fiber−fiber linkages, while in the incompatible blends, the elongated threads break easily and thus form the droplet morphology. 26,27 The dispersed phase of compatible blends is more likely to form into a fibrous morphology during processing than incompatible blends. As seen in Figure 3a, stress transfer from the matrix to the dispersed phase is difficult because of the weak interaction between the two phases, which is certified by the pulled-out PA6 phase.…”

“…Previous research on blends compatibilized by nonofillers mainly focused on particle location and its effects on the blend morphology, but the migration process of particles during blending remains unclear. Taguet et al compatibilized PS/PA6 blends by kaolin platelets, and found that kaolin platelets would migrate from the PA6 phase to the blend interface during dynamic annealing, thus limiting the coalescence of the dispersed phase. Göldel et al studied the migration of multiwalled carbon nanotubes in polymer blends.…”

h-BN Modification Using Several Hydroxylation and Grafting Methods and Their Incorporation into a PMMA/PA6 Polymer Blend

“…Nitric acid solution (HNO 3 , 68% w/w) was supplied by Prolabo (Paris, France), and gallic acid powder with purity of 98% was purchased from Acros Organics, Geel, Belgium. Silane grafting agents (Figure 1) trimethoxyoctadecylsilane (named Si-C18) and 3-aminopropyletriethoxysilane (named Si-NH 2 ) were purchased from ABCR (Lyon, France), while poly(methylmethacrylate-co-3-(triethoxysilyl)propyl methacrylate) 95/5% mol noted Si-PMMA and poly(styrene-co-3-(triethoxysilyl)propyl methacrylate) 95/5% mol noted Si-PS were synthesized in the laboratory using a protocol detailed in a previous study [64]. Polymethylmethacrylate (PMMA) Altuglas V825T was purchased from Arkema (Milan, Italy), and polyamide (PA6) Ultramid B33 was purchased from BASF (Ludwigshafen, Germany).…”

Light‐colored conductive nanorod‐mediated co‐continuous polypropylene/poly(butylene succinate) blends: Regulatory mechanism, morphology evolution, electrical, and optical properties

“…12 It is essential to selectively localize nanofillers in the governance of the blends' morphology. 13 The co-continuous morphology have been mediated with a large number of nanofillers, including silica, 14,15 nanoclay, 16,17 cellulose nanocrystal, 18 and synthetic nanorods, 5,19,20 etc. Specially, Janus particles, combining the amphiphilicity of a compatibilizer and the Pickering effect of a nanoparticle, 21,22 could impact the blends' morphology through a multiple viscoelasticity mechanism.…”