The glass transition temperature of filled polymers and its effect on their physical properties

Abstract

The glass transition temperature, dynamic shear moduli, and bulk viscosities of Phenoxy PKHH (a thermoplastic polymer made from bisphenol‐A and epichlorohydrin) filled with glass beads and Attapulgite clay were investigated. The glass temperature of the polymer increased with increasing filler concentration and with increasing specific surface area of the filler. The data were interpreted by assuming that interactions between filler particles and the polymer matrix reduce molecular mobility and flexibility of the polymer chains in the vicinity of the interfaces. From the measured moduli and the viscosities of the filled and unfilled materials, the modulus reinforcement ratio in the glassy state and the relative viscosity in the viscous state were obtained as functions of the filler type and concentration. The relative modulus for the glass bead composite system follows the Kerner equation, while the clay‐filled systems exhibit slightly greater reinforcement. The relative viscosities are strongly temperature dependent and do not follow conventional viscosity predictions for suspensions. It is suggested that the filler has a twofold effect on the viscosity of the composite materials; one is due to its mechanical presence and the other is due to modifications of part of the polymer matrix caused by interaction. Using the WLF equation to express all modifications of the matrix, one can isolate a purely mechanical contribution to the viscosity reinforcement. This mechanical part is approximately bounded by the theoretical predictions of Kerner,32 Mooney, 36 and Brodnyan,41 for suspension viscosities.

Relaxation and viscoelastic properties of heterogeneous polymeric compositions

“…Most experimental data indicate that Tg dependence on the filler content is non-linear (42), and in the form is similar to the well-known dependence of Tg on the polymer molecular weight. It might seem that since the change of Tg is associated with the restriction of molecular mobility, it would have to manifest itself the more, the thinner the polymer layer between two particles of the filler,/.e, the greater its concentration.…”

Transition metal compatibilization of poly(vinylamine) and poly(ethylene imine)

“…68,69 If the primary amino side group is protonated, then the NH stretches shift below 2900 wave numbers. 68 There is no infrared evidence for NH 3 ϩ side groups in undiluted poly(vinylamine) or its complexes in the solid state. In complexes with 4 mol % Co 2ϩ , the symmetric NH 2 stretch shifts 9 cm Ϫ1 to lower energy, the NH 2 deformation shifts 10 cm Ϫ1 to lower energy, and the CN stretch 68 at 1126 cm Ϫ1 shifts 35 cm Ϫ1 to lower energy.…”

“…When additives increase T g , explanations are based on the existence of specific interactions and the formation of complexes. 3,4 Transition metal complexation between a d-block salt and an amorphous polymer is operative in organic-inorganic hybrids [5][6][7] that exhibit enhanced glass-transition temperatures relative to T g of the undiluted polymer. 8,9 Chain mobility is hindered when transition metals coordinate to favorable ligands in the side group of a polymer via acid-base interactions.…”

Correlation between interfacial interactions and internal stresses in filled high density polyethylene

“…e.g. [29,30]. This reduction in mobility may be the result of chemical, physical and/or mechanical interactions occurring at the interface, i.e.…”