Synthesis of solvent-modified epoxies via Chemically Induced Phase Separation: A new approach towards void toughening of epoxies

Kiefer, J.; Kausch, H. H.; Hilborn, Jöns

doi:10.1007/s002890050076

Cited by 12 publications

(4 citation statements)

References 40 publications

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“…This approach is based on the use of antiplasticizers that are small molecules which behave as a modulus fortifier with respect to the polymer 5, 8. Further benefits can be expected using the pioneering ideas on chemically induced phase separation technique 9. In our case, if the antiplasticizer is designed to be fully miscible to the mixture of monomers but to phase separate before gelation in the form of soft clusters of nanometric size, then toughening is observed without any loss of materials modulus 6, 7.…”

Section: Introductionmentioning

confidence: 98%

Toughness improvement of epoxy networks by nanophase‐separating antiplasticizers

Laiarinandrasana

Halary

2011

J of Applied Polymer Sci

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International audienceTwo epoxy-amine networks were toughened by using a nanophase separating antiplasticizer at various contents ranging from 0 to 20 mol % with respect to the epoxide. These model networks were chosen to differ markedly by their glass transition temperature in the absence of additive, namely 180°C and 114°C. Net stress was measured as a function of crack opening displacement on single edge notch bending specimens. Analysis of the experimental data yielded both stiffness and fracture toughness. In addition, fracture surfaces were observed by scanning electron microscopy. Effect on both stiffness and toughness of network characteristics (nature of the hardener, amount of additive) were carefully examined. Conditions were found for which fracture energy at crack initiation substantially increases without any detrimental effect on stiffness

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Section: Introductionmentioning

confidence: 98%

Toughness improvement of epoxy networks by nanophase‐separating antiplasticizers

Laiarinandrasana

Halary

2011

J of Applied Polymer Sci

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“…Because of the limit of heat-exchange rates, thermally induced phase separation is suitable only for the preparation of thin films, where a fast heat transfer from a heated solution to the environment can be achieved. Chemically induced phase separation is also called polymerization-induced phase separation. − To carry out the chemically induced phase separation, reactive precursors are mixed with nonreactive low molecular weight or oligomeric solvents. The selection of a solvent or a mixture of solvents is very crucial, as a moderate solvent is required for the reactive precursors to give a homogeneous solution in the initial stage and becomes an immiscible solvent for the polymerized reactive precursors to obtain a phase-separated final morphology.…”

Section: Introductionmentioning

confidence: 99%

Dual Phase Separation for Synthesis of Bimodal Meso-/Macroporous Carbon Monoliths

Liang

Dai

2009

Chem. Mater.

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Polymerization-induced spinodal decomposition was conducted in glycolic solutions of phloroglucinol/ formaldehyde copolymer and poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) to synthesize bicontinuous macroporous morphologies with microdomains from 0.5 to 6 µm. The polymeric materials were further carbonized at elevated temperature to yield bimodal meso-/ macroporous carbon monoliths after the thermal decomposition of the PEO-PPO-PEO template. The bimodal porous nature of the resultant carbon monoliths was derived from the dual phase separation in which spinodal decomposition and microphase separation occurred simultaneously. We demonstrated the tunability of macropores without alteration of mesopore sizes.

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“…Incorporation of rigid inorganic or organic fillers (e.g., thermoplastic powders, core/shell type rubbers with and without functionalization) is widely practiced for impact modification of EP resins. Microvoids produced via solvent vapor‐induced phase separation10 can also fulfill the role of a toughness modifier. A very efficient method is to add functionalized liquid rubbers, like carboxyl‐ or amine‐functionalized nitrile or silicon rubbers (e.g., refs.…”

Section: Introductionmentioning

confidence: 99%

Toughening of vinylester–urethane hybrid resins through functionalized polymers

Gryshchuk

Jost

Karger‐Kocsis

2002

J of Applied Polymer Sci

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Liquid nitrile rubber, hyperbranched polyester, and core/shell rubber particles of various functionality, namely, vinyl, carboxyl, and epoxy, were added up to 20 wt % to a bisphenol-A-based vinylester-urethane hybrid (VEUH) resin to improve its toughness. The toughness was characterized by the fracture toughness (K c ) and energy (G c ) determined on compact tensile (CT) specimens at ambient temperature. Toughness improvement in VEUH was mostly achieved when the modifiers reacted with the secondary hydroxyl groups of the bismethacryloxy vinyl ester resin and with the isocyanate of the polyisocyanate compound, instead of participating in the free-radical crosslinking via styrene copolymerization. Thus, incorporation of carboxyl-terminated liquid nitrile rubber (CTBN) yielded the highest toughness upgrade with at least a 20 wt % modifier content. It was, however, accompanied by a reduction in both the stiffness and glass transition temperature (T g ) of the VEUH resin. Albeit functionalized (epoxy and vinyl, respectively) hyperbranched polymers were less efficient toughness modifiers than was CTBN, they showed no adverse effect on the stiffness and T g . Use of core/shell modifiers did not result in toughness improvement. The above changes in the toughness response were traced to the morphology assessed by dynamic mechanical thermal analysis (DMTA) and fractographic inspection of the fracture surface of broken CT specimens.

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Synthesis of solvent-modified epoxies via Chemically Induced Phase Separation: A new approach towards void toughening of epoxies

Cited by 12 publications

References 40 publications

Toughness improvement of epoxy networks by nanophase‐separating antiplasticizers

Toughness improvement of epoxy networks by nanophase‐separating antiplasticizers

Dual Phase Separation for Synthesis of Bimodal Meso-/Macroporous Carbon Monoliths

Toughening of vinylester–urethane hybrid resins through functionalized polymers

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