Formation Of Interpenetrating Polymer Network Structure Research Articles

Toughening of Epoxy Systems with Interpenetrating Polymer Network (IPN): A Review.

Epoxy resins are widely used for different commercial applications, particularly in the aerospace industry as matrix carbon fibre reinforced polymers composite. This is due to their excellent properties, i.e., ease of processing, low cost, superior mechanical, thermal and electrical properties. However, a pure epoxy system possesses some inherent shortcomings, such as brittleness and low elongation after cure, limiting performance of the composite. Several approaches to toughen epoxy systems have been explored, of which formation of the interpenetrating polymer network (IPN) has gained increasing attention. This methodology usually results in better mechanical properties (e.g., fracture toughness) of the modified epoxy system. Ideally, IPNs result in a synergistic combination of desirable properties of two different polymers, i.e., improved toughness comes from the toughener while thermosets are responsible for high service temperature. Three main parameters influence the mechanical response of IPN toughened systems: (i) the chemical structure of the constituents, (ii) the toughener content and finally and (iii) the type and scale of the resulting morphology. Various synthesis routes exist for the creation of IPN giving different means of control of the IPN structure and also offering different processing routes for making composites. The aim of this review is to provide an overview of the current state-of-the-art on toughening of epoxy matrix system through formation of IPN structure, either by using thermoplastics or thermosets. Moreover, the potential of IPN based epoxy systems is explored for the formation of composites particularly for aerospace applications.

Synthesis of PDMS-PS IPN Pervaporation Membrane for Pervaporation Recovery of Butanol

Polydimethylsiloxane (PDMS)-polystyrene (PS) interpenetrating polymer network (IPN) was prepared and characterized by FTIR, TGA, WCA, swelling experiments, and SEM. The IPN was used for pervaporation (PV) recovery of butanol. Both the permeation flux and separation factor increased with feed temperature, and both water and butanol fluxes increased with feed concentration, while no obvious effect of concentration on separation factor was found. Through the formation of IPN structure, the total flux of PDMS-PS IPN pervaporation membrane increased greatly with the decrease of separation factor. At the feed temperature of 60 °C, the IPN membrane obtained a total flux of 920.3 g/m2h with a separation factor of 9.5.

Synthesis of HTPB based PU-PS IPN membrane for pervaporation recovery of butanol

Hydroxyl terminated polybutadiene (HTPB) based polyurethane (PU)-polystyrene (PS) interpenetrating polymer network (IPN) was prepared and characterized by FTIR, TGA, WCA, swelling experiments, and SEM. The IPN was used for pervaporation (PV) recovery of butanol. Both the permeation flux and separation factor increased with feed temperature, and both water and butanol fluxes increased with feed concentration while no obvious effect of concentration on separation factor was found. Through the formation of IPN structure, the total flux of HTPB based PU increased greatly with the decrease of separation factor. At the feed temperature of 60 °C, the IPN membrane obtained a total flux of 613.3 g/m2h with a separation factor of 6.15.

High-performance interpenetrating polymer network polyurethane pervaporation membranes for butanol recovery

BACKGROUND Butanol produced by fermentation from waste biomass suffers from low final concentration. Separation of butanol from its dilute aqueous solution is of significant importance. Among various separation methods, pervaporation has been proved to be one of the most promising methods for the butanol–water system and developing pervaporation membranes with high performance is therefore of interest. RESULTS A high performance interpenetrating polymer network (IPN) polyurethane (PU) pervaporation membrane was obtained, giving membrane selectivity of 130.3 with butanol permeability of 2.5 × 104 Barrer at 60 °C. Both membrane selectivity and butanol permeability increased with feed temperature at temperatures up to 60 °C and then decreased. CONCLUSION Hydroxyl-terminated polybutadiene (HTPB) based PU was used in pervaporation recovery of butanol. Pervaporation performance was obviously improved by formation of IPN structure. The pervaporation performance was studied using the solution-diffusion model and the mechanism of performance improvement was also studied. © 2014 Society of Chemical Industry

Synthesis and Characterization of UV-Induced Interpenetrating Polymer Network (IPN) Structure of Poly(urethane acrylate) (UA Polymer)/Silica Hybrids

High transparent and homogeneous poly(urethane acrylate) (UA Polymer)/silica hybrids were obtained by using strong ionic interaction between carboxylic acid groups of the UA Polymer and amino moieties of silica resulting from 3-aminopropyltriethoxysilane (APTEOS). The ionic interaction was directly confirmed by FT-IR measurement. The homogeneity of the obtained UA Polymer/silica hybrids was examined by SEM, TM-AFM and nitrogen adsorption porosimetry studies. Thermal property of the polymer hybrids was also checked by TGA study. Furthermore, the semi-interpenetrating polymer network (semi-IPN) structured UA Polymer/silica hybrids, where UA Polymer was dispersed in silica gel matrix, were changed to the IPN structured polymer hybrids by photo-induced cross-linking between UA Polymers. The change of the surface hardness, solvent-resistant property, and surface roughness on nanometer scale depending on the formation of IPN structure was investigated.

Synthesis of IPN Polymer Hybrids by In-Situ Radical Polymerization Method and Their High Resistivity to Solvent Extraction

Abstract Two different types of polymer hybrids having an interpenetrating polymer network (IPN) of the organic gel and silica gel were prepared by the in-situ polymerization method. One type is the IPN polymer hybrids of poly(N,N′-dimethylacrylamide) gel and silica gel that were prepared by simultaneous polymerization of N,N′-dimethylacrylamide and N,N′-methylenebisacrylamide in a methanol solution of tetramethoxysilane (TMOS). The other type is IPN polymer hybrids of polystyrene gel and silica gel that were prepared by the polymerization of styrene monomer in the presence of divinylbenzene and TMOS. Radical polymerization of these organic monomers proceeded effectively in the sol-gel reaction mixture of TMOS, resulting in homogeneous glassy materials. The formation of IPN structure was confirmed by the solvent extraction. The loss of organic elements could be prevented in both cases by the incorporation of cross-linking points in the organic network. The homogeneity of these IPN polymer hybrids were supported by nitrogen porosimetry measurements. The results demonstrated that the porous silicas obtained from the polymer hybrids had high surface areas and large pore volumes and exhibited a sharp distribution of pore size below 2 nm in both types of IPN polymer hybrids. These results indicate a molecular-level integration of the organic gel and silica gel in the IPN polymer hybrids.