A bismaleimide (BMI) resin was added to an epoxy system composed of N,N′‐tetraglycidyldiaminodiphenyl methane (TGDDM) and diaminodiphenyl methane (DDM). Cure behavior of the BMI modified epoxy resins was studied by a dynamic differential scanning calorimetry (DSC) method. Dynamic DSC thermograms of the BMI modified epoxy resins indicated unimodal reaction exothermic peaks. The overall heat of reaction per unit mass decreased with BMI composition. The residual heat of reactions of the epoxy blends cured at 180°C for 3 h increased with BMI composition. Thermal stability of the epoxy system improved by incorporating BMI resin. Flexural strength and modulus increased with BMI composition.

Polyimide (PI) multilayer thin films were prepared by spin-coating from a poly(amic acid) (PAA) and poly(amic acid) ammonium salt (PAAS). PI was prepared from pyromellitic dianhydride (PMDA) and 4,4'-oxydianiline (ODA) PAA. Different compositions of PAAS were prepared by incorporating triethylamine (TEA) into PMDA-ODA PAA in dimethylacetamide. PI multilayer thin films were spin-coated from PMDA-ODA PAA and PAAS. The PAAS comprising cationic and anionic moieties were spherical with a particle size of 20~40 nm. Some particles showed layers with ammonium salts, despite poor ordering. Too much salt obstructed the interaction between the polymer chains and caused phase separation. A small amount of salt did not affect the interactions of the interlayer structure but did interrupt the stacking between chains. Thermogravimetric analysis (TGA) showed that the average decomposition temperature of the thin films was 611 o C. All the films showed almost single-step, thermal decomposition behavior. The nanostructure of the multilayer thin films was confirmed by X-ray reflectivity (XRR). The LF 43 film, which was prepared with a 4:3 molar ratio of PMDA and ODA, was comprised of uniformly spherical PAAS particles that influenced the nanostructure of the interlayer by increasing the interaction forces. This result was supported by the atomic force microscopy (AFM) data. It was concluded that the relationship between the uniformity of the PAAS particle shapes and the interaction between the layers affected the optical and thermal properties of PI layered films.

Purpose:The purpose of this study was to identify the factors influencing self-identity and menopausal symptoms their influence on level of depression in middle-aged woman. Methods: Participants were 135 middle-aged women who were living in city B, were 45-60 years old, informed of study purpose, and agreed to participate. Data were collected from December, 2012 to January, 2013 using scales measuring depression, self-identity, and menopausal symptoms. Data were analyzed using t-test, ANOVA, Scheffé test, Pearson Correlation Coefficients, and Multiple Stepwise Regression. Results: Level of depression was low, self-identity was slightly high, and menopausal symptoms were relatively low in these middle-aged women. There were significant differences in depression by perceived health status and perceived economic status. Depression had a moderate negative correlation with self-identity (r=-.49, p<.001) and a moderate positive correlation with menopausal symptoms (r=.57, p<.001). Menopausal psychological symptoms were the factor most affecting depression and explained 37% of the variance in depression. A total of 51% of variance in depression was explained by menopausal symptoms (psychological and physical), self-identity, and perceived economic status. Conclusion: Thus, an effort to improve self-identity, especially a plan to attenuate menopausal psychological symptoms is needed to reduce depression.

No abstract

We report the effect of the amount of the mesoporous material, SBA-15, on the basic traits of fully aliphatic polyimides (API). For this purpose, water soluble, fully aliphatic poly(amic acid) triethyl amine salts (PAA ( s )) were prepared and mixed with various amounts of SBA-15. Fully aliphatic polyimide hybrid composites containing the SBA 15-type mesoporous silica were synthesized successfully from bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride and alicyclic diamine, 4,4'-methylene bis(2-methylcyclohexylamine). The structure of the hybrid composites was confirmed by IR spectroscopic analysis. Scanning electron microscopy revealed the morphology of the compounds. The hybrid composites exhibited good thermal stability, reasonable transparency, and a low dielectric constant.