The Experts below are selected from a list of 84 Experts worldwide ranked by ideXlab platform
S. Grishchuk - One of the best experts on this subject based on the ideXlab platform.
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Modification of vinyl ester and vinyl ester–urethane resin-based bulk molding compounds (BMC) with acrylated epoxidized soybean and linseed oils
Journal of Materials Science, 2012Co-Authors: S. Grishchuk, J. Karger-kocsisAbstract:Acrylated epoxidized soybean and linseed oils of different characteristics were incorporated in the absence and presence of polymeric Methylene Diphenyl Isocyanate (PMDI) in a vinyl ester (VE) resin-based bulk molding compound (BMC) up to 15 wt% (with respect to VE resin). The thermal, thermo-mechanical, static fracture mechanical, dynamic impact (Charpy), and thermal degradation properties of the BMC compounds were determined. With increasing amount of functionalized plant oils the glass transition temperature ( T _g) of the matrix, the stiffness ( E modulus) and Charpy impact strength of the BMCs decreased. The static fracture toughness was slightly increased and the fracture energy remained unaffected by the modification with increasing amount of oil. Additional crosslinking of VE, induced by PMDI, markedly enhanced the T _g but yielded a large drop in the glassy modulus. This finding was traced to resin dilution and to unfavored PMDI/kaolin interactions triggered by the water content of the latter. The thermal degradation of the BMCs was less affected, however, their degradation started earlier for the modifications either with functionalized plant oil or PMDI. Dilution of VE-based BMCs with acrylated epoxidized plant oils requires reworking of the corresponding recipes to keep the property degradation limited.
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modification of vinyl ester and vinyl ester urethane resin based bulk molding compounds bmc with acrylated epoxidized soybean and linseed oils
Journal of Materials Science, 2012Co-Authors: S. Grishchuk, J KargerkocsisAbstract:Acrylated epoxidized soybean and linseed oils of different characteristics were incorporated in the absence and presence of polymeric Methylene Diphenyl Isocyanate (PMDI) in a vinyl ester (VE) resin-based bulk molding compound (BMC) up to 15 wt% (with respect to VE resin). The thermal, thermo-mechanical, static fracture mechanical, dynamic impact (Charpy), and thermal degradation properties of the BMC compounds were determined. With increasing amount of functionalized plant oils the glass transition temperature (T g) of the matrix, the stiffness (E modulus) and Charpy impact strength of the BMCs decreased. The static fracture toughness was slightly increased and the fracture energy remained unaffected by the modification with increasing amount of oil. Additional crosslinking of VE, induced by PMDI, markedly enhanced the T g but yielded a large drop in the glassy modulus. This finding was traced to resin dilution and to unfavored PMDI/kaolin interactions triggered by the water content of the latter. The thermal degradation of the BMCs was less affected, however, their degradation started earlier for the modifications either with functionalized plant oil or PMDI. Dilution of VE-based BMCs with acrylated epoxidized plant oils requires reworking of the corresponding recipes to keep the property degradation limited.
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Hybrid resins from polyIsocyanate, vinyl ester, melamine formaldehyde and water glass: structure and properties
Plastics Rubber and Composites, 2008Co-Authors: József Karger-kocsis, N. Castellà, S. GrishchukAbstract:AbstractHybrid thermosets were produced from polymeric Methylene Diphenyl Isocyanate (PMDI), styrene cross-linkable vinyl ester (VE) and water glass (WG) using melamine formaldehyde (MF) resin as additional reactive emulsifier. Vinyl ester (VE) was added to the PMDI/MF mixture in which the WG was dispersed next. The content of MF in the resin formulation was varied between 0·5 and 15 wt-%. The resulting water in oil type (W/O) emulsion (water=WG, oil=organic phase composed of PMDI+VE+MF) was cured at room temperature for 24 h followed by post-curing at T=100°C for 4 h. The chemorheology of the hybrid resins was assessed by plate/plate rheometry. Information on the morphology of the cured hybrid resins was received from scanning electron microscope (SEM), atomic force microscopic (AFM) and dynamic mechanical thermal analysis (DMTA) studies. The mechanical and fracture mechanical properties as well as the resistance to thermal degradation of the hybrid thermosets were determined and discussed.
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Hybrid resins from polyIsocyanate/vinyl ester/ water glass systems: Structure and properties
European Polymer Journal, 2007Co-Authors: S. Grishchuk, N. Castellà, József Karger-kocsisAbstract:Abstract Polysilicate modified polyurea/vinyl ester hybrid resins were produced by dispersing water glass (WG) in a mixture of vinyl ester (VE) and polyIsocyanate in presence of a liquid phosphate as emulsifier. As styrene-crosslinkable VE resins bisphenol A (BA) and novolac types (N), whereas as polyIsocyanate a polymeric Methylene Diphenyl Isocyanate (PMDI) were used. The structure and selected properties of the hybrid resins were determined and compared to those of the neat VEs and polysilicate filled polyurea (denoted as 3P resin). Using VE for resin hybridization, which worked as an additional emulsifier for the WG/PMDI/phosphate system, resulted in a fine particle dispersion of the polysilicate. It was found that the type of VE affected not only the dispersion of WG (and thus of the polysilicate) but also the network formation of the polyurea/VE hybrids and their properties. Information about the structure of the polysilicate filled hybrid resins was gained from dynamic-mechanical thermal analysis (DMTA), scanning electron and atomic force microscopic measurements. It was argued that the resin hybridization yielded a conetwork instead of an interpenetrating one. The properties of the hybrid systems were determined by DMTA, fracture mechanical tests, thermogravimetric analysis and flammability measurements. It was established that the stiffness and resistance to thermal degradation of the initial 3P resin was strongly improved by hybridization with VEs. The fracture toughness (Kc) proved to be less sensitive to the formulation of the hybrid resins. On the other hand, the fracture energy (Gc) and limiting oxygen index experienced a positive deviation from the additivity as a function of the 3P/VE composition, at least in a given range.
J Kargerkocsis - One of the best experts on this subject based on the ideXlab platform.
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modification of vinyl ester and vinyl ester urethane resin based bulk molding compounds bmc with acrylated epoxidized soybean and linseed oils
Journal of Materials Science, 2012Co-Authors: S. Grishchuk, J KargerkocsisAbstract:Acrylated epoxidized soybean and linseed oils of different characteristics were incorporated in the absence and presence of polymeric Methylene Diphenyl Isocyanate (PMDI) in a vinyl ester (VE) resin-based bulk molding compound (BMC) up to 15 wt% (with respect to VE resin). The thermal, thermo-mechanical, static fracture mechanical, dynamic impact (Charpy), and thermal degradation properties of the BMC compounds were determined. With increasing amount of functionalized plant oils the glass transition temperature (T g) of the matrix, the stiffness (E modulus) and Charpy impact strength of the BMCs decreased. The static fracture toughness was slightly increased and the fracture energy remained unaffected by the modification with increasing amount of oil. Additional crosslinking of VE, induced by PMDI, markedly enhanced the T g but yielded a large drop in the glassy modulus. This finding was traced to resin dilution and to unfavored PMDI/kaolin interactions triggered by the water content of the latter. The thermal degradation of the BMCs was less affected, however, their degradation started earlier for the modifications either with functionalized plant oil or PMDI. Dilution of VE-based BMCs with acrylated epoxidized plant oils requires reworking of the corresponding recipes to keep the property degradation limited.
J. Karger-kocsis - One of the best experts on this subject based on the ideXlab platform.
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Modification of vinyl ester and vinyl ester–urethane resin-based bulk molding compounds (BMC) with acrylated epoxidized soybean and linseed oils
Journal of Materials Science, 2012Co-Authors: S. Grishchuk, J. Karger-kocsisAbstract:Acrylated epoxidized soybean and linseed oils of different characteristics were incorporated in the absence and presence of polymeric Methylene Diphenyl Isocyanate (PMDI) in a vinyl ester (VE) resin-based bulk molding compound (BMC) up to 15 wt% (with respect to VE resin). The thermal, thermo-mechanical, static fracture mechanical, dynamic impact (Charpy), and thermal degradation properties of the BMC compounds were determined. With increasing amount of functionalized plant oils the glass transition temperature ( T _g) of the matrix, the stiffness ( E modulus) and Charpy impact strength of the BMCs decreased. The static fracture toughness was slightly increased and the fracture energy remained unaffected by the modification with increasing amount of oil. Additional crosslinking of VE, induced by PMDI, markedly enhanced the T _g but yielded a large drop in the glassy modulus. This finding was traced to resin dilution and to unfavored PMDI/kaolin interactions triggered by the water content of the latter. The thermal degradation of the BMCs was less affected, however, their degradation started earlier for the modifications either with functionalized plant oil or PMDI. Dilution of VE-based BMCs with acrylated epoxidized plant oils requires reworking of the corresponding recipes to keep the property degradation limited.
József Karger-kocsis - One of the best experts on this subject based on the ideXlab platform.
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Hybrid resins from polyIsocyanate, vinyl ester, melamine formaldehyde and water glass: structure and properties
Plastics Rubber and Composites, 2008Co-Authors: József Karger-kocsis, N. Castellà, S. GrishchukAbstract:AbstractHybrid thermosets were produced from polymeric Methylene Diphenyl Isocyanate (PMDI), styrene cross-linkable vinyl ester (VE) and water glass (WG) using melamine formaldehyde (MF) resin as additional reactive emulsifier. Vinyl ester (VE) was added to the PMDI/MF mixture in which the WG was dispersed next. The content of MF in the resin formulation was varied between 0·5 and 15 wt-%. The resulting water in oil type (W/O) emulsion (water=WG, oil=organic phase composed of PMDI+VE+MF) was cured at room temperature for 24 h followed by post-curing at T=100°C for 4 h. The chemorheology of the hybrid resins was assessed by plate/plate rheometry. Information on the morphology of the cured hybrid resins was received from scanning electron microscope (SEM), atomic force microscopic (AFM) and dynamic mechanical thermal analysis (DMTA) studies. The mechanical and fracture mechanical properties as well as the resistance to thermal degradation of the hybrid thermosets were determined and discussed.
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Hybrid resins from polyIsocyanate/vinyl ester/ water glass systems: Structure and properties
European Polymer Journal, 2007Co-Authors: S. Grishchuk, N. Castellà, József Karger-kocsisAbstract:Abstract Polysilicate modified polyurea/vinyl ester hybrid resins were produced by dispersing water glass (WG) in a mixture of vinyl ester (VE) and polyIsocyanate in presence of a liquid phosphate as emulsifier. As styrene-crosslinkable VE resins bisphenol A (BA) and novolac types (N), whereas as polyIsocyanate a polymeric Methylene Diphenyl Isocyanate (PMDI) were used. The structure and selected properties of the hybrid resins were determined and compared to those of the neat VEs and polysilicate filled polyurea (denoted as 3P resin). Using VE for resin hybridization, which worked as an additional emulsifier for the WG/PMDI/phosphate system, resulted in a fine particle dispersion of the polysilicate. It was found that the type of VE affected not only the dispersion of WG (and thus of the polysilicate) but also the network formation of the polyurea/VE hybrids and their properties. Information about the structure of the polysilicate filled hybrid resins was gained from dynamic-mechanical thermal analysis (DMTA), scanning electron and atomic force microscopic measurements. It was argued that the resin hybridization yielded a conetwork instead of an interpenetrating one. The properties of the hybrid systems were determined by DMTA, fracture mechanical tests, thermogravimetric analysis and flammability measurements. It was established that the stiffness and resistance to thermal degradation of the initial 3P resin was strongly improved by hybridization with VEs. The fracture toughness (Kc) proved to be less sensitive to the formulation of the hybrid resins. On the other hand, the fracture energy (Gc) and limiting oxygen index experienced a positive deviation from the additivity as a function of the 3P/VE composition, at least in a given range.
Z. Petrovic - One of the best experts on this subject based on the ideXlab platform.
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Thermal stability enhancement of polyurethanes by surface treatment
Journal of Thermal Analysis and Calorimetry, 1994Co-Authors: J. H. Flynn, Z. PetrovicAbstract:Both oxidation and methoxymethylation of the surfaces of a series of MDI (Methylene Diphenyl Isocyanate) and TDI (toluene diIsocyanate) polyether and polyester soft segment 1–4 butanediol polyurethanes result in increased thermal stability as measured by TG. Explosive loss of mass above the hard segment melting temperature suggests that the diffusion of the dissociated diIsocyanate moiety is hindered at lower temperatures. Thus suppression of the depolycondensation reaction by chemical blockage of the surface may result in a material with an increased service life at use temperatures as thermal stability of a polyurethane may depend upon the low diffusivity of its diIsocyanate comonomer. The effect of vacuum, oxygen and water vapor on the kinetics of mass-loss of several of the polyurethanes is presented.
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Thermal stability enhancement of polyurethanes by surface treatment
Journal of thermal analysis, 1994Co-Authors: J. H. Flynn, Z. PetrovicAbstract:Both oxidation and methoxymethylation of the surfaces of a series of MDI (Methylene Diphenyl Isocyanate) and TDI (toluene diIsocyanate) polyether and polyester soft segment 1–4 butanediol polyurethanes result in increased thermal stability as measured by TG. Explosive loss of mass above the hard segment melting temperature suggests that the diffusion of the dissociated diIsocyanate moiety is hindered at lower temperatures. Thus suppression of the depolycondensation reaction by chemical blockage of the surface may result in a material with an increased service life at use temperatures as thermal stability of a polyurethane may depend upon the low diffusivity of its diIsocyanate comonomer. The effect of vacuum, oxygen and water vapor on the kinetics of mass-loss of several of the polyurethanes is presented. Wie durch TG nachgewiesen wurde, resultieren sowohl Oxidation als auch Methoxymethylierung der Oberfläche einer Serie von 1–4 Butandiolpolyurethanen mit MDI-(MethylenDiphenylisocyanat) und TDI-(Toluoldiisocyanat) Polyether-und Polyestersoftsegmenten in einer gesteigerten thermischen Stabilität. Die explosionsartige Massenabgabe oberhalb der Hardsegment-Schmelztemperatur deutet darauf hin, daß die Diffusion der dissoziierten Diisocyanatkomponente bei niedrigeren Temperaturen behindert ist. Somit kann die Unterdrückung der Depolykondensationsreaktion durch chemisches Blockieren der Oberfläche in einem Material mit erhöhter Standzeit bei Gebrauchstemperetauren resultieren, da die thermische Stabilität eines Polyurethanes von der geringen Diffusivität seines Diisocyanat-Komonomeres abhängen kann. Weiterhin wird der Einfluß von Vakuum, Sauerstoff und Wasserdampf auf die Kinetik der Massenabgabe einiger Polyurethane dargestellt.