Influence of the process on phase separation induced by radical copolymerization of styrene and divinylbenzene in the presence of reactive polyurethane network precursors

Abstract

ABSTRACT:Interpenetrating polymer systems based on crosslinked polyurethane (PU) and polystyrene (PS) were prepared at room temperature by a one-shot (in situ) method, starting from an initial homogeneous mixture of reagents via noninterfering mechanisms. Both polymerizations were performed either simultaneously or one after the other. True simultaneity at every stages of the process is not possible. Despite the difference in refractive index of the components, hazy or optically clear films were obtained, thus indicating various levels of phase separation, also confirmed by glass transition temperature (T g ) measurements.The results suggest that controlling the chemistry and process (crosslink density, composition, and time sequence of events) of in situ interpenetrating network formation will give various morphologies, and hence properties, ranging from microphase separated materials to larger macrophase separated materials.

Multimorphic Materials: Spatially Tailoring Mechanical Properties via Selective Initiation of Interpenetrating Polymer Networks

“…[13] Mechanical properties in IPNs can be tailored by controlling the morphology, or more specifically, the degree of mixing. [13][14][15][16][17][18][19][20] Early work by Widmaier and coworkers demon strated that the degree of mixing between two polymer networks could be manipulated kinetically during the formation of the two networks. [16,[21][22][23] Recently the use of orthogonal Access to multimaterial polymers with spatially localized properties and robust interfaces is anticipated to enable new capabilities in soft robotics, such as smooth actuation for advanced medical and manufacturing technologies.…”

“…[ 13 ] Mechanical properties in IPNs can be tailored by controlling the morphology, or more specifically, the degree of mixing. [ 13–20 ] Early work by Widmaier and coworkers demonstrated that the degree of mixing between two polymer networks could be manipulated kinetically during the formation of the two networks. [ 16,21–23 ] Recently the use of orthogonal chemistry in forming IPNs has gone a step further to investigate how differences in initiation and propagation can control morphology, and as a result, mechanical properties.…”

Phase-Separated Interpenetrating Polymer Networks

“…The number of additional entanglements between unlike chains increases with increasing cross-link density of the primary PU network. For the same system both polymerizations were performed either simultaneously or one after the other [306]. It was discovered that the degree of phase separation depends on the experimental conditions.…”