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Bo Jönsson - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of an immunoaffinity extraction column for enrichment of adducts between human serum albumin and Hexahydrophthalic Anhydride in plasma.
Biomedical Chromatography, 2008Co-Authors: Gunvor Johannesson, Monica H. Kristiansson, Bo Jönsson, Christian H. LindhAbstract:An immunoaffinity extraction (IAE) column was prepared for extraction of adducts between human serum albumin (HSA) and Hexahydrophthalic Anhydride (HHPA). HHPA is a strong sensitizer inducing immunoglobulin E antibodies in vivo. Polyclonal antibodies from a rabbit immunized with keyhole limpet hemocyananin-HHPA conjugate were purified using a Protein A Sepharose gel. To obtain antibodies with optimal affinity towards HHPA-protein adducts, HHPA-specific antibodies were selected using an N-hydroxysuccinimide-Sepharose column coupled with albumin-HHPA conjugate. Antibodies eluted from this column at pH 2.2 were selected to prepare the IAE column. The column was evaluated using 2 mL plasma spiked with HSA-HHPA conjugate. The column was eluted with glycine buffer at pH 2.0. The conjugates in the eluate were hydrolyzed to the corresponding HHP acid and quantified by mass spectrometry. The average recovery of HHPA adducts in 11 experiments was 68% with a coefficient of variation (CV) of 7%. The column's capacity to bind protein-HHPA adducts was found to be linear in the range of 0.15-1.2 nmol conjugate. The evaluation showed that the IAE column had adequate affinity towards the HHPA adducts and that the adducts could be extracted with good recovery and precision from a large volume of plasma.
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Adducts between nucleophilic amino acids and Hexahydrophthalic Anhydride, a structure inducing both types I and IV allergy.
Biomarkers, 2005Co-Authors: S. R. Ahlfors, Monica H. Kristiansson, Christian H. Lindh, Bo Jönsson, C. HanssonAbstract:Haptens causing type I allergy have been shown to predominantly form lysine adducts in the carrier protein, while many haptens giving rise to type IV allergy preferentially form adducts with cysteine residues. Hexahydrophthalic Anhydride derivatives are strong sensitizers capable of inducing allergic rhinitis, asthma and urticaria (type I allergy) and allergic contact dermatitis (type IV allergy). The ability of Hexahydrophthalic Anhydride (HHPA) to form adducts with nucleophilic amino acids and a model peptide in vitro is presented. Adduct formation was monitored by high-performance liquid chromatography with ultraviolet light/vis detection (LC-UV/vis) and high-performance liquid chromatography with mass spectrometric detection (LC/MS). The characterization was obtained by nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS and MS/MS). It was found that HHPA formed adducts with N(alpha)-acetylated lysine and cysteine and the non-acetylated alpha-amino group of proline and, to some extent, also with other nucleophilic amino acids. The adducts with lysine and proline were chemically stable. Addition of one HHPA to a model carrier peptide with all important nucleophilic amino acid residues showed N-terminal proline to be the major site of reaction. The addition of a second hapten gave a lysine adduct, but a minor cysteine adduct was also found. The cysteine-HHPA adducts were shown to be chemically unstable and participated in further reactions with lysine forming lysine-HHPA adducts. The results will be useful for understanding the formation of HHPA-protein adducts with the capability of being markers of exposure, and also to a deeper understanding of the chemical structures causing types I and IV allergy.
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Correlations between air levels of Hexahydrophthalic Anhydride(HHPA) and HHPA-adducted albumin tryptic peptides in nasal lavage fluid from experimentally exposed volunteers
Rapid Communications in Mass Spectrometry, 2004Co-Authors: Monica H. Kristiansson, Christian H. Lindh, Bo JönssonAbstract:Organic acid Anhydrides (OAAs) are low molecular weight, reactive compounds extensively used in industry. Exposure to these compounds may lead to allergic symptoms such as rhinitis and asthma. It is important to develop better and more informative methods for assessment of exposure to OAAs. The aim of this study was to develop a method for analysis of specific Hexahydrophthalic Anhydride (HHPA)-adducted tryptic peptides of human serum albumin (HSA) in nasal lavage (NAL). Furthermore, these peptides were evaluated as biomarkers of exposure. The proteins in the NAL samples were reduced, alkylated and digested with trypsin and the obtained peptides were analyzed using liquid chromatography/tandem mass spectrometry. The total amount of hydrolyzable HHPA in an HHPA-HSA conjugate was used for calibration. A deuterium-labeled HHPA-HSA conjugate was used as internal standard. Five volunteers were exposed to 10, 40 and 80 μg/m3 of HHPA in an exposure chamber and NAL samples were collected before and after exposure. Acceptable precisions of the assay at 13–14% were found for three adducted peptides. The mean levels of these three peptides for the five subjects ranged between 5–22, 15–75 and 33–125 pmol/mL NAL for the exposures at 10, 40 and 80 μg/m3, respectively. High correlations between air levels and the measured peptides were found on an individual basis but there were large inter-individual differences ranging between 63 and 110% for the three peptides. The large differences remained after protein adjustments. It was possible to detect exposures below 10 μg/m3 with the method. Thus, these adducted peptides may be used as biomarkers of exposure, which may better estimate the risk than previous biomarkers developed for OAAs. Copyright © 2004 John Wiley & Sons, Ltd.
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In vivo conjugation of nasal lavage proteins by Hexahydrophthalic Anhydride.
Toxicology and Applied Pharmacology, 2004Co-Authors: Gunvor Johannesson, Christian H. Lindh, Jörn Nielsen, Birgitta Björk, Seema Rosqvist, Bo JönssonAbstract:Hexahydrophthalic Anhydride (HHPA), an industrially important chemical, is a highly allergenic compound. The aim of this work was to identify proteins in nasal lavage fluid (NLF) that form adducts with HHPA. Such bindings may induce production of specific immunoglobulin E (IgE) or affect physiological mechanisms of the proteins. NLF was obtained from HHPA-exposed volunteers, workers and exposed guinea pigs. HHPA-binding proteins were visualized with immunoblotting using a polyclonal antiserum against HHPA. The proteins were excised from sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) gels, digested with trypsin and identified by tandem mass spectrometry (MS/MS) and database searches. The antiserum was found to be specific for HHPA-bound proteins. In vivo formed HHPA-binding proteins in humans were identified as antileukoproteinase, immunoglobulin G (IgG), immunoglobulin A (IgA), serum albumin and lactoferrin. In addition, several proteins binding to HHPA were found in NLFs from guinea pigs but these could not be identified from database searches. Hypotheses for development of airways diseases by adduction of this allergenic compound to the NLF proteins in humans were established.
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Determination of Hexahydrophthalic Anhydride adducts to human serum albumin
Biomarkers, 2003Co-Authors: Monica H. Kristiansson, Christian H. Lindh, Bo JönssonAbstract:Hexahydrophthalic Anhydride (HHPA) is a highly sensitizing industrial chemical that is known to covalently bind to endogenous proteins. The aim of this study was to determine the binding sites of HHPA to human serum albumin (HSA). Conjugates between HSA and HHPA, at two different molar ratios, were synthesized under physiological conditions. The conjugates were digested with trypsin and Pronase E to obtain specific peptides and amino acids, which were separated by liquid chromatography (LC). Fractions containing modified peptides were detected through quantification of hydrolysable HHPA using LC coupled to a triple quadrupole mass spectrometer with electrospray ionization. Modified residues in albumin were identified by sequence analyses using nanoelectrospray quadrupole time-of-flight mass spectrometry. A total of 36 HHPA adducts were found in the HSA–HHPA conjugate with 10 times molar excess of added HHPA. In the conjugate with a molar ratio of 1:0.1 of added HHPA, seven HHPA adducts were found bound to...
Christian H. Lindh - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of an immunoaffinity extraction column for enrichment of adducts between human serum albumin and Hexahydrophthalic Anhydride in plasma.
Biomedical Chromatography, 2008Co-Authors: Gunvor Johannesson, Monica H. Kristiansson, Bo Jönsson, Christian H. LindhAbstract:An immunoaffinity extraction (IAE) column was prepared for extraction of adducts between human serum albumin (HSA) and Hexahydrophthalic Anhydride (HHPA). HHPA is a strong sensitizer inducing immunoglobulin E antibodies in vivo. Polyclonal antibodies from a rabbit immunized with keyhole limpet hemocyananin-HHPA conjugate were purified using a Protein A Sepharose gel. To obtain antibodies with optimal affinity towards HHPA-protein adducts, HHPA-specific antibodies were selected using an N-hydroxysuccinimide-Sepharose column coupled with albumin-HHPA conjugate. Antibodies eluted from this column at pH 2.2 were selected to prepare the IAE column. The column was evaluated using 2 mL plasma spiked with HSA-HHPA conjugate. The column was eluted with glycine buffer at pH 2.0. The conjugates in the eluate were hydrolyzed to the corresponding HHP acid and quantified by mass spectrometry. The average recovery of HHPA adducts in 11 experiments was 68% with a coefficient of variation (CV) of 7%. The column's capacity to bind protein-HHPA adducts was found to be linear in the range of 0.15-1.2 nmol conjugate. The evaluation showed that the IAE column had adequate affinity towards the HHPA adducts and that the adducts could be extracted with good recovery and precision from a large volume of plasma.
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Adducts between nucleophilic amino acids and Hexahydrophthalic Anhydride, a structure inducing both types I and IV allergy.
Biomarkers, 2005Co-Authors: S. R. Ahlfors, Monica H. Kristiansson, Christian H. Lindh, Bo Jönsson, C. HanssonAbstract:Haptens causing type I allergy have been shown to predominantly form lysine adducts in the carrier protein, while many haptens giving rise to type IV allergy preferentially form adducts with cysteine residues. Hexahydrophthalic Anhydride derivatives are strong sensitizers capable of inducing allergic rhinitis, asthma and urticaria (type I allergy) and allergic contact dermatitis (type IV allergy). The ability of Hexahydrophthalic Anhydride (HHPA) to form adducts with nucleophilic amino acids and a model peptide in vitro is presented. Adduct formation was monitored by high-performance liquid chromatography with ultraviolet light/vis detection (LC-UV/vis) and high-performance liquid chromatography with mass spectrometric detection (LC/MS). The characterization was obtained by nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS and MS/MS). It was found that HHPA formed adducts with N(alpha)-acetylated lysine and cysteine and the non-acetylated alpha-amino group of proline and, to some extent, also with other nucleophilic amino acids. The adducts with lysine and proline were chemically stable. Addition of one HHPA to a model carrier peptide with all important nucleophilic amino acid residues showed N-terminal proline to be the major site of reaction. The addition of a second hapten gave a lysine adduct, but a minor cysteine adduct was also found. The cysteine-HHPA adducts were shown to be chemically unstable and participated in further reactions with lysine forming lysine-HHPA adducts. The results will be useful for understanding the formation of HHPA-protein adducts with the capability of being markers of exposure, and also to a deeper understanding of the chemical structures causing types I and IV allergy.
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Correlations between air levels of Hexahydrophthalic Anhydride(HHPA) and HHPA-adducted albumin tryptic peptides in nasal lavage fluid from experimentally exposed volunteers
Rapid Communications in Mass Spectrometry, 2004Co-Authors: Monica H. Kristiansson, Christian H. Lindh, Bo JönssonAbstract:Organic acid Anhydrides (OAAs) are low molecular weight, reactive compounds extensively used in industry. Exposure to these compounds may lead to allergic symptoms such as rhinitis and asthma. It is important to develop better and more informative methods for assessment of exposure to OAAs. The aim of this study was to develop a method for analysis of specific Hexahydrophthalic Anhydride (HHPA)-adducted tryptic peptides of human serum albumin (HSA) in nasal lavage (NAL). Furthermore, these peptides were evaluated as biomarkers of exposure. The proteins in the NAL samples were reduced, alkylated and digested with trypsin and the obtained peptides were analyzed using liquid chromatography/tandem mass spectrometry. The total amount of hydrolyzable HHPA in an HHPA-HSA conjugate was used for calibration. A deuterium-labeled HHPA-HSA conjugate was used as internal standard. Five volunteers were exposed to 10, 40 and 80 μg/m3 of HHPA in an exposure chamber and NAL samples were collected before and after exposure. Acceptable precisions of the assay at 13–14% were found for three adducted peptides. The mean levels of these three peptides for the five subjects ranged between 5–22, 15–75 and 33–125 pmol/mL NAL for the exposures at 10, 40 and 80 μg/m3, respectively. High correlations between air levels and the measured peptides were found on an individual basis but there were large inter-individual differences ranging between 63 and 110% for the three peptides. The large differences remained after protein adjustments. It was possible to detect exposures below 10 μg/m3 with the method. Thus, these adducted peptides may be used as biomarkers of exposure, which may better estimate the risk than previous biomarkers developed for OAAs. Copyright © 2004 John Wiley & Sons, Ltd.
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In vivo conjugation of nasal lavage proteins by Hexahydrophthalic Anhydride.
Toxicology and Applied Pharmacology, 2004Co-Authors: Gunvor Johannesson, Christian H. Lindh, Jörn Nielsen, Birgitta Björk, Seema Rosqvist, Bo JönssonAbstract:Hexahydrophthalic Anhydride (HHPA), an industrially important chemical, is a highly allergenic compound. The aim of this work was to identify proteins in nasal lavage fluid (NLF) that form adducts with HHPA. Such bindings may induce production of specific immunoglobulin E (IgE) or affect physiological mechanisms of the proteins. NLF was obtained from HHPA-exposed volunteers, workers and exposed guinea pigs. HHPA-binding proteins were visualized with immunoblotting using a polyclonal antiserum against HHPA. The proteins were excised from sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) gels, digested with trypsin and identified by tandem mass spectrometry (MS/MS) and database searches. The antiserum was found to be specific for HHPA-bound proteins. In vivo formed HHPA-binding proteins in humans were identified as antileukoproteinase, immunoglobulin G (IgG), immunoglobulin A (IgA), serum albumin and lactoferrin. In addition, several proteins binding to HHPA were found in NLFs from guinea pigs but these could not be identified from database searches. Hypotheses for development of airways diseases by adduction of this allergenic compound to the NLF proteins in humans were established.
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Determination of Hexahydrophthalic Anhydride adducts to human serum albumin
Biomarkers, 2003Co-Authors: Monica H. Kristiansson, Christian H. Lindh, Bo JönssonAbstract:Hexahydrophthalic Anhydride (HHPA) is a highly sensitizing industrial chemical that is known to covalently bind to endogenous proteins. The aim of this study was to determine the binding sites of HHPA to human serum albumin (HSA). Conjugates between HSA and HHPA, at two different molar ratios, were synthesized under physiological conditions. The conjugates were digested with trypsin and Pronase E to obtain specific peptides and amino acids, which were separated by liquid chromatography (LC). Fractions containing modified peptides were detected through quantification of hydrolysable HHPA using LC coupled to a triple quadrupole mass spectrometer with electrospray ionization. Modified residues in albumin were identified by sequence analyses using nanoelectrospray quadrupole time-of-flight mass spectrometry. A total of 36 HHPA adducts were found in the HSA–HHPA conjugate with 10 times molar excess of added HHPA. In the conjugate with a molar ratio of 1:0.1 of added HHPA, seven HHPA adducts were found bound to...
Hans Welinder - One of the best experts on this subject based on the ideXlab platform.
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Serum albumins are the major site for in vivo formation of hapten-carrier protein adducts in plasma from humans and guinea-pigs exposed to type-1 allergy inducing Hexahydrophthalic Anhydride.
Clinical & Experimental Allergy, 2001Co-Authors: Gunvor Johannesson, Christian H. Lindh, Seema Rosqvist, Hans Welinder, Bo JönssonAbstract:BACKGROUND: Organic acid Anhydrides (OAAs) are highly allergenic compounds used in the chemical industry. The OAAs probably act as haptens but the proteins that form conjugates with OAAs in vivo are still unknown. Conjugates between the Anhydrides and serum albumins (SAs) have routinely been used when testing for OAA-specific antibodies. However, the use of SA as the carrier-protein in these tests has never been evaluated. OBJECTIVE: The aim of this study was to identify major and also immunologically relevant protein conjugates of a particularly sensitizing OAA, Hexahydrophthalic Anhydride (HHPA), in plasma. METHODS: Plasma was obtained from a HHPA-exposed worker, from a guinea-pig (GP) exposed to HHPA in an exposure chamber for 2 weeks (8 h/day, 5 days/week) and from a GP exposed once, nose-only, to tritium-labelled HHPA for 8 h. The plasma was fractionated using ion exchange chromatography and gel filtration. These fractions and also aliquots of unfractioned plasma were hydrolysed, derivatized and analysed for Anhydride adduct content using gas chromatography-mass spectrometry. Further, plasma from the tritium labelled HHPA-exposed GP was separated by SDS gel electrophoresis and analysed by autoradiography. In addition, immunologically relevant proteins were identified through specific IgE and IgG immunoblottings using sera from exposed workers. RESULTS: For humans > 85% and for GPs > 74% of the HHPA-adducts coeluted with SA in plasma. Autoradiography of GP-plasma shows a single 66 kDa protein that binds HHPA. IgE immunoblotting shows a major 66 kDa and a minor 28 kDa protein which could be inhibited by HHPA-SA conjugate. IgG immunoblotting showed a major 66 kDa protein and several minor protein bands. CONCLUSION: This study shows SA to be the major protein in plasma that forms adducts in vivo with HHPA. The results also show that in an in vitro synthesized HHPA plasma protein conjugate, HHPA-specific IgE and IgG antibodies bind preferably to the SA. (Less)
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Relationship between IgG1 levels and airway responses in guinea pigs actively and passively sensitized to Hexahydrophthalic Anhydride
Allergy, 1998Co-Authors: X.-d. Zhang, Hans Welinder, Jan Lötvall, Hirokazu Arakawa, Staffan SkerfvingAbstract:Organic acid Anhydrides (OAAs) are industrial chemicals that may cause induction of specific IgE and airway symptoms in exposed workers. They are a good model for studies of relationships between chemical structure and the sensitizing potential of reactive low-molecular-weight compounds. Hexahydrophthalic Anhydride (HHPA) is such a compound. This study aimed to evaluate the relationship between specific IgG1 levels and airway responses in a model to predict the sensitizing potential of OAAs. Guinea pigs were either actively or passively sensitized to HHPA. For active sensitization, guinea pigs were injected i.d. with 0.1 ml of olive oil (vehicle) or 0.05, 0.5, or 5% HHPA in olive oil. Passive sensitization was performed by i.p. injection of different volumes of antisera (0.75-6 ml, either unheated to keep IgE or heated to destroy IgE) taken from HHPA-sensitized guinea pigs. Specific antibody levels were evaluated with ELISA and passive cutaneous anaphylaxis. Animals were challenged 16-18 days after active sensitization, or 2 days after passive sensitization, by intratracheal instillation with HHPA conjugated to guinea pig serum albumin (HHPA-GPSA; 0.05% in saline), and the immediate effects on lung resistance (RL), and plasma extravasation, measured as Evans blue dye extravasation, for up to 6 min were recorded. Active sensitization caused production of specific IgG1. Provocation with HHPA-GPSA caused an increase of both RL and Evans blue dye extravasation, which was dependent upon the active sensitization dose. Challenge with HHPA-GPSA in passively sensitized guinea pigs also produced an increase in both RL and Evans blue dye extravasation which was related to the IgG1 level. In the guinea pig model of HHPA-induced airway allergy, the airway responses are closely related to the serum levels of specific IgG1. Thus, the IgG1 levels induced by the immunization may reflect the sensitizing potential of HHPA.
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Haemoglobin adducts and specific immunoglobulin G in humans as biomarkers of exposure to Hexahydrophthalic Anhydride.
Biomarkers, 1997Co-Authors: Bo Jönsson, Christian H. Lindh, Hans WelinderAbstract:The aim of this study was to determine whether haemoglobin adducts Hb of Hexahydrophthalic Anhydride HHPA and HHPA specific immunoglobulin G IgG can be used as biomarkers of exposure to HHPA. The exposures of HHPA in 10 workers were determined from the mean urinary Hexahydrophthalic acid HHP acid levels range 76-3300 nmol HHP acid mmol-1 creatinine during a period of 4 weeks. Blood was collected at the end of the period and Hb-HHPA adducts were analysed by gas chromatography mass spectrometry. The Hb-HHPA adduct levels ranged from 0.45 to 24.7 pmol g-1 Hb. There was a close correlation between the urinary HHP acid levels and the amount of Hb-HHPA adducts r = 0.87 . One day exposures to HHPA and methylHexahydrophthalic Anhydride MHHPA in 142 workers were determined from analysis of urinary HHP acid range 0-3300 nmol HHP acid mmol-1 creatinine and methylHexahydrophthalic acid MHHP acid; range 0-1700 nmol MHHP acid mmol-1 creatinine. HHPA specific IgG were analysed in the 142 workers with an ELISA method. The optical density for HHPA specific IgG varied between 0 and 1.25. There was no statistically significant correlation between the sum of the urinary HHP acid and MHHP acid and the HHPA specific IgG r = 0.12; p = 0.14 . Thus, Hb-HHPA adducts seem to be applicable as biomarkers of exposure to HHPA while the possible role of HHPA specific IgG as an indicator of exposure has to be further evaluated.
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Antibody specificity to the chemical structures of organic acid Anhydrides studied by in-vitro and in-vivo methods
Toxicology, 1997Co-Authors: Xing-dong Zhang, Jan Lötvall, Staffan Skerfving, Hans WelinderAbstract:The objective of the study was to evaluate the structure-activity relationship for the antigenic activity of different organic acid Anhydrides (OAAs). The specificity of guinea pig (GP) IgG1 to different Anhydrides was studied by ELISA-inhibition, PCA, and airway provocation tests of cross-reactivity with different OAA conjugates. In the airway provocation tests, lung resistance and plasma extravasation of Evan's Blue dye was measured. The ELISA-inhibition tests showed a wide range in antibody specificity. Modelling of ring configuration, methyl group substitution, double bond position, and cis/trans isomerism of Anhydride forming carboxyl groups influenced the specificity. There was a general consistency in cross-reactivity of anti-cis-Hexahydrophthalic Anhydride IgG1 versus GP serum albumin conjugates of trans-Hexahydrophthalic Anhydride, phthalic Anhydride, and succinic Anhydride as shown by ELISA-inhibition, PCA, and airway provocation tests. It is concluded that various modifications of the chemical structures of a hapten are recognized by the hapten-specific antibodies, and that these differences may have clinical relevance. In particular, the ring structure and the positions of double bonds and of methyl groups are important. Further, the in-vitro ELISA-inhibition tests show a good agreement with the in-vivo PCA and bronchial provocation tests.
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Direct measurement of Hexahydrophthalic Anhydride in workplace air with a transportable Fourier transform infrared spectrometer
American Industrial Hygiene Association Journal, 1996Co-Authors: Christian H. Lindh, Bo Jönsson, Hans WelinderAbstract:A method for direct measurement of Hexahydrophthalic Anhydride (HHPA) in workplace air by use of a Fourier transform infrared (FTIR) spectrometer was developed. Two visits were made to a plant manufacturing capacitors where HHPA was used. On the first visit a calibration method was developed according to what was expected to give the best calibration. This was performed by collection of 82 FTIR spectra from the air while simultaneously taking samples with a reference method using Amberlite XAD-2 sorbent tubes. On the second visit, two weeks later, the calibration method was used for prediction of HHPA concentrations (n=52) in air; these were compared with XAD-2 determinations. The predicted FTIR values as a function of the XAD-2 determinations were used to evaluate some parameters regarding the FTIR method. The limit of detection was 120 µg HHPA/m3, and the precision at 150 µg/m3 was 22% and at 400 µg/m3 8%. When sampling from a pure HHPA atmosphere the obtained concentration by the FTIR was 103% of that ...
Jurgen Finter - One of the best experts on this subject based on the ideXlab platform.
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morphology and toughness stiffness balance of nanocomposites based upon Anhydride cured epoxy resins and layered silicates
Macromolecular Chemistry and Physics, 1999Co-Authors: Carsten Zilg, Rolf Mülhaupt, Jurgen FinterAbstract:Basic correlations between polymer morphology, silicate superstructures, glass temperature, stiffness and toughness of thermoset nanocomposites were investigated as a function of layered silicate type and content. The nanocomposites were based upon Hexahydrophthalic Anhydride-cured bisphenol A diglycidyl ether and layered silicates such as synthetic fluoromica (Fmica), purified sodium bentonite and synthetic hectorite, all of which were rendered organophilic by means of ion-exchange with various mono- and difunctional alkyl ammonium ions. Enhanced toughness was associated with the formation of dispersed anisotropic laminated nanoparticles consisting of intercalated layered silicates. Nanocomposite superstructures were imaged by means of transmission electron microscopy (TEM) and atomic force microscopy (AFM).
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Morphology and toughness/stiffness balance of nanocomposites based upon Anhydride‐cured epoxy resins and layered silicates
Macromolecular Chemistry and Physics, 1999Co-Authors: Carsten Zilg, Rolf Mülhaupt, Jurgen FinterAbstract:Basic correlations between polymer morphology, silicate superstructures, glass temperature, stiffness and toughness of thermoset nanocomposites were investigated as a function of layered silicate type and content. The nanocomposites were based upon Hexahydrophthalic Anhydride-cured bisphenol A diglycidyl ether and layered silicates such as synthetic fluoromica (Fmica), purified sodium bentonite and synthetic hectorite, all of which were rendered organophilic by means of ion-exchange with various mono- and difunctional alkyl ammonium ions. Enhanced toughness was associated with the formation of dispersed anisotropic laminated nanoparticles consisting of intercalated layered silicates. Nanocomposite superstructures were imaged by means of transmission electron microscopy (TEM) and atomic force microscopy (AFM).
Carsten Zilg - One of the best experts on this subject based on the ideXlab platform.
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morphology and toughness stiffness balance of nanocomposites based upon Anhydride cured epoxy resins and layered silicates
Macromolecular Chemistry and Physics, 1999Co-Authors: Carsten Zilg, Rolf Mülhaupt, Jurgen FinterAbstract:Basic correlations between polymer morphology, silicate superstructures, glass temperature, stiffness and toughness of thermoset nanocomposites were investigated as a function of layered silicate type and content. The nanocomposites were based upon Hexahydrophthalic Anhydride-cured bisphenol A diglycidyl ether and layered silicates such as synthetic fluoromica (Fmica), purified sodium bentonite and synthetic hectorite, all of which were rendered organophilic by means of ion-exchange with various mono- and difunctional alkyl ammonium ions. Enhanced toughness was associated with the formation of dispersed anisotropic laminated nanoparticles consisting of intercalated layered silicates. Nanocomposite superstructures were imaged by means of transmission electron microscopy (TEM) and atomic force microscopy (AFM).
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Morphology and toughness/stiffness balance of nanocomposites based upon Anhydride‐cured epoxy resins and layered silicates
Macromolecular Chemistry and Physics, 1999Co-Authors: Carsten Zilg, Rolf Mülhaupt, Jurgen FinterAbstract:Basic correlations between polymer morphology, silicate superstructures, glass temperature, stiffness and toughness of thermoset nanocomposites were investigated as a function of layered silicate type and content. The nanocomposites were based upon Hexahydrophthalic Anhydride-cured bisphenol A diglycidyl ether and layered silicates such as synthetic fluoromica (Fmica), purified sodium bentonite and synthetic hectorite, all of which were rendered organophilic by means of ion-exchange with various mono- and difunctional alkyl ammonium ions. Enhanced toughness was associated with the formation of dispersed anisotropic laminated nanoparticles consisting of intercalated layered silicates. Nanocomposite superstructures were imaged by means of transmission electron microscopy (TEM) and atomic force microscopy (AFM).