Transparent Interpenetrating Polymer Networks Research Articles

Tensile, fracture and impact behavior of transparent Interpenetrating Polymer Networks with polyurethane-poly(methyl methacrylate)

Transparent Interpenetrating Polymer Networks (IPNs) with poly(methyl methacrylate) (PMMA) as the stiff phase and polyurethane (PU) as the ductile phase with varying PMMA:PU ratios in the range of 90:10 to 70:30 were formulated. Static tensile and fracture tests indicate significant failure strain and crack initiation toughness enhancements with a loss of stiffness relative to PMMA. Dynamic fracture tests were conducted using a long-bar impact loading apparatus in conjunction with an optical method and high-speed photography. Low-velocity impact tests were also performed using a drop-tower. Dynamic fracture and low-velocity impact responses show that an optimum range of PMMA:PU ratios in the IPNs can produce enhanced fracture toughness and impact energy absorption capability when compared to PMMA. Fractographic examination supports macro-measurements by showing a distinct change in surface morphology associated with improved macroscale fracture toughness.

Synthesis and characterization of high performance, transparent interpenetrating polymer networks with polyurethane and poly(methyl methacrylate)

AbstractTransparent, interpenetrating polymer network (IPN) materials were synthesized using polyurethane (PU) and poly(methyl methacrylate) (PMMA). PMMA contributed to the transparency and rigidity necessary for use in impact‐resistant applications, whereas PU contributed to toughness. Several factors affecting the physical properties, such as the ratio of PU to PMMA, curing profile, inclusion of different isocyanates for the PU phase, and use of an inhibitor in the PMMA phase, were investigated. Full‐IPNs were synthesized so that the two polymer networks would remain entangled with one another, and domain sizes of each system were reduced, mitigating phase separation. Both simultaneous IPNs, polymerization of monomers occurring at the same time, and sequential IPNs, polymerization of monomers occurring at different temperatures, were synthesized for studying the reaction kinetics and final morphologies. The phase morphology and the final thermal and mechanical properties of the IPNs prepared were evaluated. Findings suggest that samples containing ∼80 wt% PMMA, 1,6‐diisocyanatohexane 99+% (DCH), and an inhibitor with the MMA monomer created favorable results in the thermo‐mechanical and optical properties. POLYM. ENG. SCI. 2013. © 2012 Society of Plastics Engineers

Ring-opening polymerization in aqueous emulsion applied to the preparation of interpenetrating networks based on telechelic polysiloxanes

Anionic ring-opening polymerization of 1,3,5,7-tetramethyl-1,3,5,7-tetraphenyIcycIotetrasiloxane (c-PMPS tetramer) was performed by using the new process of aqueous emulsion Suitable conditions were found which lead to the formation of stable emulsions, and telechelic oligomers with alpha,omega-SiOH end groups having a remarkably narrow molecular weight distribution ((M) over bar(w)/(M) over bar(n) < 1.3) were obtained. Reproducible results and a tremendous reduction of back-biting reactions are observed by using this very simple process which does not require the drastic purifications of the classical anionic polymerization. Those telechelic PMPS oligomers were used to prepare transparent interpenetrating polymer networks (IPNs) with polybenzyl or polymethylmethacrylate networks.

Polyurethane-poly(methyl methacrylate) interpenetrating polymer networks. I. Synthesis, characterization, and preliminary blood compatibility studies

Simultaneous polyurethane–poly(methyl methacrylate) (PU–PMMA) interpenetrating polymer networks (IPNs) were synthesized with the PMMA polymerization initiated at room temperature. Transparent IPNs with better miscibility and synergism of mechanical properties were obtained. Dynamic mechanical analysis data indicated that up to 30% PMMA can be incorporated into PU networks without substantial phase separation. The PU–PMMA 90/10 IPNs elicit less than 2% hemolysis, suggesting that these materials could be used as blood contacting materials. © 1996 John Wiley & Sons, Inc.