Morphology of phase separated blends of poly(cyclohexyl methacrylate) with poly(vinyl acetate)

Abstract

ABSTRACT:Blends of poly(vinyl acetate) (PVAc) and poly(cyclohexyl methacrylate) (PCHMA) labeled by copoly-merization with 4-methacryloylamine-4�-nitrostilbene (Sb), with (1-pyrenylmethyl)methacrylate (Py) or with 3-(methacryloylamine)propyl-N-carbazole (Cbz), were prepared by casting dilute solutions in tetrahydrofurane (THF) or chloroform onto silanized glass plates. The resulting films were studied by epifluorescence microscopy, microfluorescence spectroscopy, DSC and optical microscopy. Epifluorescence micrography probes the chemical composition of the different regions in phase separated blends, with black areas corresponding to PVAc rich regions and colored areas corresponding to labeled PCHMA rich regions. The technique also visualizes primary and secondary morphologies, which depend on the composition of the polymer blend and on the casting solvent. Mixtures containing 80 wt % PCHMA show, in general, a bicontinuous primary morphology suggesting a spinodal demixing mechanism. Solvent effects are particularly relevant for 50% and 20% PCHMA samples showing morphologies composed of PCHMA rich domains, in a matrix of solvent-dependent compositions. Samples cast from chloroform are more homogeneous and the matrix is always highly fluorescent. In contrast, the domains of samples cast from THF are heterogeneous in size and shape and the matrix is non-fluorescent, being thus formed by nearly pure PVAc. Small voids are formed in the polymer-air interface. They are submicrometric for THF cast films and disappear with annealing at 122°C. For chloroform cast samples they are much less frequent and appear well ordered, forming a mostly hexatic two dimensional network.

Effect of the morphology of two phase polymer blends on glass transition temperature

“…Poly(cyclohexyl methacrylate), PChMA, sample was obtained by radical polymerization and labelled with (1-pirenyl-methyl)methacrylate (Py) (polyscience) as reported previously [13,14]. PVAc was purchased from polysciences and used without any further purification.…”

“…Other methods are based on the measurement of the nonradiative energy transfer that depends on the distance between both fluorophores (guest in different domain), and therefore on the interpenetrating in the interface between the individual domain [10][11][12]. Epifluorescence microscopy (EFM) and fluorescence microspectroscopy were also employed to study the domains incompatible in blends with poly(vinyl acetate) [11,13,14]. However, the more sensitive technique is that the smaller domain it can detect.…”

Influence of solvent composition and degree of reaction on the formation of surface microtopography in a thermoset siloxane–urethane system

“…Reversibly switchable morphology was obtained with a PS-PMMA diblock copolymer upon exposure to acetone and CS 2 [1]. Rate of evaporation of the solvent during casting has an effect on morphology of polymer blend [2]. The shape of a polymer chain in ternary solution has been studied by Monte Carlo simulation and blob model was used to study a polymer blend of two-crosslinked polymers in presence of a common solvent [3,4].…”