Curing Kinetics Analysis and Properties Researches of Cyanate Composites

The powdery nitrile butadiene rubbers (P-NBRs) are employed to improve the comprehensive properties of the bisphenol A dicyanate ester (BADCY). The addition of P-NBRs affecting on the curing kinetics of the composites is analyzed and characterized by gelation test, differential scanning calorimentry (DSC) and Fourier transformed infrared spectroscopy (FTIR). And the contents of P-NBRs affecting on the mechanical and dielectric properties of the P-NBRs/BADCY composites are also investigated. Results show that the addition of P-NBRs has little influence on the cure activation energy. The mechanical properties of the P-NBRs/BADCY composites are optimal with 5 wt% P-NBRs. The dielectric constant values of the P-NBRs/BADCY composites are increased with the increasing addition of P-NBRs.

Functional organogels from lipophilic L-glutamide derivative immobilized on cyclotriphosphazene core

A novel cyclotriphosphazene-based low-molecular weight organogelator was prepared by immobilization of six dialkylated L-glutamide derivatives on a cyclotriphosphazene core, and its ability as a self-assembling organogelator was investigated. The organogelator exhibited enhanced gelation ability and chirality, and thixotropic property for self-restoring to a gel state; this was compared to the corresponding L-glutamide-derived organogelator without the core. The gelation test, transmission electron microscopy observation, and circular dichroism (CD) spectral study showed that the gelation and aggregation ability were enhanced by immobilization onto the cyclotriphosphazene core. Gels in chloroform and cyclohexane-ethanol (95:5) mixture showed an unusual thixotropic property.

DETECTION OF SOLUBLE FIBRIN MONOMER COMPLEXES - COMPARISON OF A HAEMAGGLUTINATION ASSAY WITH THE ETHANOL GELATION TEST

Hypercoagulability and disseminated intravascularcoagulation (DIC) are characterized by the presenceof circulating fibrin monomer complexes in plasma.In342 patients with possible DIC fibrin monomers, fibrinogen, reptilase time, antithrombin III and othercoagulation parameters were determined at frequent intervals.Testing of soluble fibrin monomer complexeswas performed using a sensitive and reliable haemagglut- ination assay, with red cells sensitized by fibrin monomers (FM-Test) and the ethanol gelation test(EGT). Method comparison regarding the influence offibrinogen levels and fibrin degradation products shows that high fibrinogen levels lead to false positive results with EGT. The same effect is observed forfibrin degradation products and EGT whereas no influence of fibrinogen level and fibrin degradation products on the FM-Test occurs.It could be shown that with normal fibrinogen concentrations (200-400 mg/dl) the positive test results by FMT and EGT are comparable, whereas with fibrinogen concentrations below 200 mg/dl the number of positive results obtained with the EGT amounted to half the number given by FMT. In the case of fibrinogen concentrations above 400 mg/dl, positive results obtained with EGT were 3.3 times higher than FMT. Nearlyidentical results were obtained by comparing the influence of degradation products. In case of high degradation product concentrations, EGT gives 4.5 timesmore positive results than FMT.Further we compared the number of positive test results obtained by the FMT with the level of AT III because it is wellknown that the AT IIIHevel decreases caused by proteolytic activity generated in DIC.In this study it could be shown that fibrin monomer increases in parallel with the decrease of AT III. Thiseffect does not occur with fibrin degradation products.