Resorcinol Diglycidyl Ether Research Articles

Phase effects in curing epoxide compositions

Kinetics of polycondensation of resorcinol diglycidyl ether with m-phenylenediamine were studied at 60°C in the presence of accelerating (dichlorophenol) and retarding (dichlorobenzene) additives. When the process takes place slowly the intensity of light scattering at the initial stages of curing increases at a much faster rate than with rapid curing. Higher intensity of scattering is not directly related to network formation, but is determined by a violation of conditions of compatibility of components in the reaction system. In those systems, where equilibrium phase distribution takes place at the initial stages, the elastic modulus increases considerably. Results obtained were discussed from the point of view of relaxation processes, stimulated by the well-developed surface of the finely dispersed phase as a result of syneresis.

Association of chemically induced forestomach cell proliferation and carcinogenesis

A number of chemicals have been shown to cause malignant neoplasms in the forestomach of Fischer 344 rats when administered chronically by gavage. The present study was designed to identify early forestomach lesions following 2-week repeated gavage administration of some of these forestomach carcinogens. In this manner, we attempted to examine the hypothesis that early cell proliferation is associated with repetitive gavage administration of these chemicals. Groups of 8 or more male F344 rats received 1 of 6 reported forestomach carcinogens (ethyl acrylate (EtAc), diglycidyl resorcinol ether(DGRE), 1,2-dibromoethane (DBE), 1,2-dibromo-3-chloropropane (DBCP), 1-chloro-2-methylpropene (dimethylvinyl chloride, DMVC) and 3-chloro-2-methylpropene (CMP)), 1 of 2 structurally related chemicals (methyl methacrylate (MMA) and dichloroethane (DCE)) which were negative in chronic carcinogenicity studies or the vehicle (corn oil) alone 5 days/week for 2 weeks. Histopathologic examination of forestomachs of rats killed 24 h after the last dose indicated no significant difference in the incidence or severity of epithelial cell proliferation in the rat forestomach between the vehicle control group and the 2 negative control groups. In contrast, the incidence and severity of epithelial cell proliferation of the rat forestomach in every group treated with a forestomach carcinogen was significantly higher than the incidence in the vehicle or negative control groups. These results suggest that early epithelial cell proliferation of the forestomach may be associated with at least some chemicals that induce forestomach neoplasia following chronic administration by gavage.

Concerning the nature of molecular movement in epoxy-amine network glassy polymers

The NMR impulse method has been used to study the relaxation properties of a number of model epoxy-polymers based on the diglycidyl ether of resorcinol with various concentrations of crosslinks, degrees of branching and with crosslinking fragments of various types. During glass formation, molecular movement in the network polymers is accomplished by segments of at least two types: node with adjacent chain fragments and chain fragments respectively.

Chemical mutagenesis testing in Drosophila. III. Results of 48 coded compounds tested for the National Toxicology Program.

Forty-eight chemicals were tested for mutagenicity in Drosophila melanogaster. Each compound was tested first for the induction of sex-linked recessive lethals (SLRLs) by feeding the chemical in a solution of 5% aqueous sucrose. If it was not mutagenic by this route, the chemical was tested by injection in a solution of 0.7% aqueous NaCl. If found inactive, the compound was not tested further. If it was mutagenic, the compound was tested for the induction of reciprocal translocations (RTs) using the exposure protocol and germ cell stage that yielded positive results in the SLRL assay. Eight chemicals (diglycidylresorcinol ether, AF-2, alloxan monohydrate, 1-aziridine ethanol, p,p'-DDE, dichloroacetonitrile, 1,3-dichloropropene, and 3,3'-dimethylbenzidine dihydrochloride) were found to induce SLRLs. Only diglycidylresorcinol ether also induced RTs.

Uptake, metabolism and mutagenic activity of aromatic glycidyl compounds

Aromatic diglycidyl compounds are very active mutagens when assayed in in vitro tests. In vivo, however, resorcinol diglycidyl ether provided no evidence for the clastogenic activity, while diglycidylaniline exhibited definite mutagenic activity in the micronucleus test. Since the only difference between these two compounds lies in the binding mode of the glycidyl groups to the aromatic nucleus (i.e. ether oxygen vs. aminic nitrogen), this apparent discrepancy in mutagenic activity led to the question of the mechanisms involved in such an activity difference. Although no clear signs of differential uptake or excretion could be detected in mice, differences could be seen in the spectrum of urinary metabolites; while resorcinol diglycidyl ether seemed to become fully converted to the genetically inactive bis-diol compound, a sizeable proportion of diglycidylaniline was converted only to the diol-epoxide. In vitro investigations and enzyme kinetic measurements with postmitochondrial supernatant of rat or mouse liver homogenate (S-9) finally yielded the biochemical explanation for this behaviour, as they showd a very low affinity of the diol-epoxide metabolite of diglycidylaniline for the epoxide hydrolase, normally involved in the degradation of such compounds. The diol-epoxide obtained from resorcinol diglycidyl ether, on the other hand, has an affinity to the degradation enzyme similar to, or even higher than, the one measured with the parent substance.

The mutagenicity of mono- and di-functional aromatic glycidyl compounds

Although epoxides are very important compounds in today's technology, they are not as well investigated for their carcinogenic and mutagenic properties as their economical importance would suggest. The present study tried, on one hand, to bridge the gap between microbial testing of such compounds and the in vivo mammalian test system. On the other hand, the comparative testing of structurally related substances was expected to yield some clues as to the structural determinants of possible in vivo mutagenic activity. Our investigations with 4 compounds of similar structure, namely glycidylmethylaniline (GMA), diglycidylaniline (DGA), phenylglycidylether (PGE), and resorcinol diglycidyl ether (RDGE), first demonstrated that, in bacterial assays, all 4 epoxides acted as potent mutagens. Only the 2 difunctional epoxides, however, were active in an in vitro chromosomal aberration assay with CHO cells. That such in vitro results cannot be supposed to represent the in vivo situation is again demonstrated by the discovery that only one of the two in vitro active substances (and in fact it is the less active one) also has a damaging effect in vivo. It, therefore, seems quite justifiable to conclude that two structural features must be combined in an aromatic glycidyl compound if it is to exert chromosome damaging activity in vivo: The substance must possess 2 epoxy functions, and they must be bound to the aromatic nucleus by an aminic nitrogen. The industrial use of aromatic glycidyl ethers might, therefore, be considered not to pose a great systemic risk for mutagenicity or carcinogenicity, without completely excluding the possibility of local effects.

Study of epoxide polymers based on resorcinol diglycidyl ether modified by low-molecular weight rubber

The authors have studied the influence of modifying low molecular weight polybutadiene rubber additives with terminal carboxyl groups on the deformation strength and relaxation properties of epoxide polymers based on the diglycidyl ether of resorcinol. It is shown that the introduction of low molecular weight rubber into an epoxide polymer leads to the formation of biphasic systems with a high degree of molecular incompatibility and a set of good physicomechanical properties.

Calorimetric study of the reaction of the diglycidyl ether of resorcinol with m-phenylenediamine

1. The kinetic laws of the polymerization of the digylcidyl ester of resorcinol under the action of m-phenylenediamine have been studied calorimetrically. 2. The kinetic curves are described by the equation of a second-order autocatalytic reaction. The rate of the reaction is proportional to the concentration of that of the reactants taken in deficiency and to the concentration of OH groups. 3. The specific heat of opening of an epoxide ring depends on the amine:epoxide ratio, its minimum value being found at stoichiometry. 4. An increase in the rate of the reaction when an excess of amine is present is explained by the catalytic action of the excess of amine.

Kinetics and mechanism of the reaction of the diglycidyl ether of resorcinol with m-phenylenediamine

1. The kinetics of the hardening of the diglycidyl ether of resorcinol in the presence of m-phenylenediamine has been studied by the potentiometric titration method. 2. The kinetic curves are described by the second-order equation of an autocatalytic reaction. The rate of the reaction is proportional to the concentration of reactant taken in lower concentration and to the concentration of OH groups. 3. The beginning of the deviation from the equation found coincides with the moment of a marked increase in rigidity due to the passage of the system into the vitreous state.

Effect of temperature on the strength and deformation characteristics of crosslinked polymers based on epoxide oligomers

The deformation of epoxide polymers over a wide temperature range has been studied in the present work. The polymers investigated were synthesized from the diglycidyl ether of resorcinol and 4,4′-diaminodiphenylsulphone, taken in various molar proportions. It is shown that strain hardening is observed in the region of the glass transition temperature during deformation. At temperatures above the glass transition temperature, the equation σ= G ∞( γ−1/ γ 2), where γ=1+ ε and G ∞ is the equilibrium high elastic modulus, satisfactorily describes the experimental results. A correlation dependence has been obtained between the tensile strength in the high elastic condition and the distribution of overstresses in the network structure.

Molecular mobility study in crosslinked polyepoxides by means of paramagnetic particles

This is a study of the rotary diffusion correlation times of spin markers and probe in a polymer produced by polycondensing diaminopentane, diglycidyl ether of resorcinol and phenylglycidyl ether. The behaviour of the paramagnetic particles (PMP) has been found to depend on the type and structure of the network, which is determined by the ratio of bi- to mono-functional epoxy compounds present. An attempt is being made to establish the link between the type of PMP dynamics and the molecular movements of network fragments.

Kinetics of formation and relaxation characteristics of crosslinked polymers prepared from resorcinol diglycidyl ether

Kinetics of formation of crosslinked polymers prepared from resorcinol diglycidyl ether (RDGE) and 4,4′-diaminodiphenyl sulphone and relaxation properties were studied by electro-physical methods. A method was proposed for determining the activation energy of this process using typical points on curves showing conductivity in relation to time. By analysing the variation of dielectric constant in the range of phase transition of RDGE a hypothesis was framed concerning the existence in the melt of stable associates with parallel orientation of molecules. It was shown that an increase of solidification temperature restricts the relaxation time of the high temperature process. In polymers obtained with amine deficiency segmental mobility was recorded as defects in the three dimensional network. Crosslinked polymers obtained with amine excess are characterized by structural heterogeneity which is shown in the form of narrow maxima on curves of the temperature dependence of tan δ. It was shown that with excess concentrations of RDGE starting from 1,4 of the stoichiometric, the latter functions as a plasticiser.

The kinetics of network formation during the interaction of diglycidyl ethers with diamines

A kinetic study was made of changes in the MWD of condensation products of the diglycidyl ether of resorcinol and 4,4′-diaminodiphenylsulphone. On comparing the results with the statistical theory it appears that satisfactory agreement between theory and experiment exists in the range of conversion degrees up to the gel point, but thereafter considerable differences are observed. Possible reasons why this is so are suggested

低温硬化性エポキシレジンモルタルの強度発現性と結合剤のゲル化以前の性質 ＩＩ

One kind of hardener, four kinds of polyepoxide diluents, and nine kinds of liquid resins were used in the present study. As the result of experiments on the temperature dependence of viscosity using liquid epoxy resins in the temperature range of +19°to -16°C, it was found that all materials should be modified when used under conditions below freezing point.The viscosity of 144 kinds of liquid resins prepared by adding diluents to liquid epoxy resins at the ratio of 12 to 48phr was measured at -6°C. Using 65 kinds of liquid resins with viscosity under 50000cps, the bond strength by tension was measured according to JIS K 6849 at -6°C.The bond strength of 51 kinds of liquid resins showed values higher than 150kg/cm2. Eight kinds of liquid resins were selected from these and used in the subsequent experiments.The viscosity and gel time of equivalent mixtures of liquid resins and hardeners were measured. All mixtures showed viscosity under 50000cps.Strength tests of epoxy resin mortars subjected to 8 days or 6 months curing, and 6 months cured jointing of successive pours to cement mortar were conducted. The strength of test specimens of 6 months curing generally was low in the case when the binders gave negative or negligible heat generation during gelation.The best results can be obtained in the case of epoxy resin mortars using liquid resins which contained diglycidyl ether of resorcinol as the main ingredient.

Thermal properties of an epoxide resin cured with bicyclo Diels‐Alder anhydride adducts

AbstractThe thermal properties of polymers derived from resorcinol diglycidyl ether cured with several bicyclo Diels‐Alder anhydride adducts have been investigated. Increased char yields and decreased rates of weight loss were observed for these systems as compared to polymers cured by Diels–Alder adducts from acyclic dienes. This is explained on the basis of a reverse Diels‐Alder reaction which these bicyclo adducts undergo at lower temperatures than do adducts from acyclic dienes.

Thermal degradation of epoxide polymers

AbstractThe thermal degradation of five crosslinked epoxide polymers were studied in vacuo by differential thermogravimetry. Three of the polymers were prepared by reacting methyl nadic anhydride, maleic anhydride, and m‐phenylenediamine with diglycidyl ether of bisphenol‐A; the other two were obtained by reacting methyl nadic anhydride and m‐phenylenediamine with resorcinol diglycidyl ether. Tenmilligram powdered samples were heated over the temperature range from 25° to 925°C. at a rate of 5°C./min. Differential thermogravimetric curves showed that the polymers incorporating methyl nadic anhydride decomposed in two distinct stages, whereas those based on m‐phenylenediamine or maleic anhydride degraded in only one stage. This difference in mechanism of decomposition is attributed to decarboxylation of ester groups having the methyl nadicdicarboxylic structure in the polymers. Substitution of a 2,2‐diphenylpropyl group for a phenyl group in resorcinol diglycidyl ether, to give diglycidyl ether of bisphenol‐A, influenced appreciably the maximum rates of decomposition of the corresponding polymers. In the case of the polymer based on m‐phenylenediamine, the rate was increased by this substitution, but for the polymer derived from methylnadic anhydride the rate was decreased.