Phase separation in the polyurethane/poly(2‐hydroxyethyl methacrylate) semi‐interpenetrating polymer networks synthesized by different ways

The thermal, dynamic mechanical analysis, morphology and mechanical properties of semi‐interpenetrating polymer networks based on crosslinked polyurethane (PU) and poly(2‐hydroxyethyl methacrylate) (PHEMA) synthesized by photopolymerization and by thermopolymerization have been investigated. The thermal analysis has evidenced the two glass temperature transitions in the semi‐IPNs and this is confirmed by the thermodynamic miscibility investigation of the systems. The Dynamic Mechanical Analysis spectra have shown that the phase separation is more significant in the thermopolymerized semi‐IPNs: the tan δ peaks of constituent polymers are more distinct and the minimum between the two peaks is deeper. The calculated segregation degree values of semi‐IPN's components are significantly higher for thermopolymerized semi‐IPNs, thereby the process of phase separation in the thermopolymerized semi‐IPNs is more developed. The structures of two series of samples investigated by SEM are completely different. The mechanical properties reflect these changes in structure of semi‐IPNs with increasing amount of PHEMA and with the changing of the method of synthesis. The results suggest that the studied semi‐IPNs are two‐phase systems with incomplete phase separation. The semi‐IPN samples with early stage of phase separation demonstrate higher mechanical characteristics. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Evaluation of the effects of specialized therapeutic canned food on the course of iron-deficiency anemia in young children

A total of 25 normal children and 131 children with iron-deficiency anemia (IDA) were investigated, 53 out of 131 IDA patients served as controls and received a standard food ration for children suffering from IDA, the rest received nutrition containing medicinal canned food. The following paraclinical parameters were evaluated in all the children investigated: red blood cell and hemoglobin content, calcium concentration, the content of ascorbic acid and vitamin B1, iron metabolism indices (serum iron, general and latent iron-binding capacity of the blood serum, coefficient of transferrin saturation with iron, serum ferritin). The results of the study have shown a favourable effect of the special-purpose medicinal canned food on IDA course in young children that necessitates their wide production and practical use.