Recent studies on interpenetrating polymer networks

Abstract

Recent investigations on interpenetrating polymer networks (IPNs) have included two component IPNs from polyurethanes and poly(methacrylates) and two component IPNs from polyurethanes and epoxies. All the IPNs were prepared by the simultaneous polymerization technique (SIN‐IPNs). Two types of IPNs, polyurethane‐poly(methyl methacrylate) (PU/PMMA) and polyurethane‐poly(methyl methacrylate‐methacrylic acid) (PU/PMMA‐MAA) were prepared. Improved phase miscibility and decreasing extent of phase separation was observed in both types of IPNs with increasing the NCO/OH ratio, decreasing molecular weight of the polyol in the PU and introduction of charge groups. A comparison was made between full‐IPNs, pseudo‐IPNs, graft copolymers and related homopolymers from polyurethanes and epoxies. Increased compatibility in full‐IPNs and graft copolymers was observed by means of DSC, SEM and was also further substantiated by a shift toward single Tgs as determined by dynamic mechanical spectroscopy. The introduction of opposite charge groups in two‐component IPNs from polyurethanes and epoxies led to improved compatibility (no phase separation) and enhanced mechanical properties.

Interpenetrating polymer networks based on castor oil, XVIII

“…Since historical synthesis of IPNs,' a tremendous amount of work of IPNs has emerged from the laboratories of Sperling, 273 Frisch et al, 4, 5 Hourston et a1.,6-s and Hermant and Meyer? Castor oil has been extensively used in the "one shot" reaction injection molding (RIM) or high pressure impingement mixing ( HPIM) and reinforced RIM processes 10~12 and IPNs syntheses.2s'2 Sperling and co-workers 12,13 reported a series of IPNs from castor-oil-based polyurethane derived from 2,4-toluene diisocyanate and polymerizing styrene monomer in the presence of 5% p-divinyl benzene as crosslinker.…”

Microheterogeneous polymer systems prepared by suspension polymerization of methyl methacrylate in the presence of poly(-caprolactone)

“…Some attempts were directed towards polyurethanes based on poly(ether glycol)s as modifiers. [3,4] The use of a lower modulus cement as matrix material based upon poly(ethyl methacrylate) [5] and poly(butyl methacrylate) [6] have been other alternative approaches to modify the properties of this material. Full Paper: Poly(methyl methacrylate) -polycaprolactone (PMMA/PCL) microheterogeneous beads were synthesized by suspension polymerization starting from methyl methacrylate (MMA) monomer and PCL, which was synthesized by ring-opening polymerization of ecaprolactone using ZnCl 2 as initiator.…”

Applications of Isocyanation for Polymer Systems

“…IPNs have received great attention due to their unusual properties, especially enhancement of tensile strength. This property enhancement is attributed to increased cross-linking density or due to permanent physical chain entanglement in the IPNs (20)(21)(22).…”