Simultaneous interpenetrating networks of a polyurethane and poly(methyl methacrylate). I. Metastable phase diagrams

Abstract

Any simultaneous interpenetrating network (SIN) synthesis contains three key events. These are gelation of polymer I, gelation of polymer II, and phase separation of polymer I from polymer II. Metastable phase diagrams of SINs are developed, in which the time occurrence of these three events is represented. A polyurethane/poly(methyl methacrylate) (PU/PMMA) system was chosen as a model. Polymerization kinetics were followed in situ for both PU and PMMA using Fourier Transform Infrared Spectroscopy (FTIR) with the aid of a heated demountable cell. Glass transitions of fully cured samples were determined by dynamic mechanical spectroscopy (DMS) and differential scanning calorimetry (DSC). Phase separation was determined by the onset of turbidity, and gelation of the first gelling polymer was determined by the sudden resistance of the system to flow. As a result, a metastable phase diagram was constructed for the four‐component SIN system (the two monomers and their respective polymers) as a tetrahedron in three dimensions with the two monomers and two polymers at the four apexes. Phase separation and gelations of the two polymers are indicated by various surfaces. These surfaces intersect at lines and curves, representing unique conditions of an SIN synthesis, e.g., simultaneous gelation of both polymers, or simultaneous phase separation and gelation of polymer I, etc. These conditions are critical in terms of the development of the SIN morphology, dividing the reaction space into specific regions. Finally, it is shown how the tetrahedron diagram helps visualize the course of the three key events during SIN synthesis, and provides direction for controlling them. © 1995 John Wiley & Sons, Inc.

The Current Status of Interpenetrating Polymer Networks

“…(68,71) also studied the distribution of the remaining MMA monomer at the end of the polymerization. In brief, PU-PMMA SINs were prepared as above.…”

Rubber-Modified Glassy Amorphous Polymers Prepared via Chemically Induced Phase Separation. 4. Comparison of Properties of Semi- and Full-IPNs, and Copolymers of Acrylate−Aliphatic Epoxy Systems

“…9 Initially, IPNs were considered as quasi-homogeneous; however, in most systems microscopic phase separation occurs sometimes on a scale of tens of nanometers only. 10,11 In some cases, these morphologies can indeed yield unique mechanical properties. Examples are IPNs of polymethacrylates with polyurethane [12][13][14][15][16] or siloxanes, 17 and poly(ethylene terephthalate) with castor oil, 18 which all can possess, for certain compositions, an extremely high strain at break.…”

Simultaneous interpenetrating networks of a polyurethane and poly(methyl methacrylate). II. Partitioning of MMA monomer in the last stages of polymerization

“…90% conversion of MMA, 13,20 subsequent polymerization of MMA is slowed considerably. However, complete conversion of MMA has been noted using Fourier transform infrared ( FTIR) spectroscopy in such SINS (even greater than the limiting conversion due to vitrification in pure PMMA samples) .…”

“…The samples were synthesized in the manner described before. 13 In brief, the PPG polyether diol and T M P triol were mixed and dried a t 60°C in Table I SIN Materials and Recipes Used" vacuum for ca. 30 min, in a 1:l equivalent ratio.…”