Assessment of bioscompatibility of isocyanurate-containing polyurethanes with ifosphamide by in vivo and in vitro methods.

Background. The creation of polymeric composite materials with pronounced biological activity, which are able to act as implants with local prolonged action of the immobilized substance can be widely used in medical practice. Objective. Study of cellular reactions of surrounding tissues of experimental animals to implantation of polymeric composite materials based on isocyanurate-containing polyurethanes with ifosfamide, study of histotoxicity of the obtained materials by tissue culture method. Methods. Polymeric composite materials based on isocyanate-containing polyurethanes without and with ifosfamide were implanted into the body of white laboratory Wistar rats. Cellular responses of the organism and possible changes in the structure of test specimens after implantation were studied by light microscopy by analysis of histological micropreparations. In order to study the peculiarities of the dynamics of growth and development of fibroblastic elements, the method of tissue culture was used. Results. Conducted biological studies by in vivo and in vitro methods allowed to evaluate the effect of immobilized ifosfamide in the structure of isocyanurate-containing polyurethanes on cellular reactions of surrounding tissues during implantation in experimental animals, as well as the effect of extracts from developed polymer samples on cultured cell growth. Conclusion. It was found that the implantation of isocyanurate-containing polyurethanes with ifosfamide led to the development of intense cellular reactions in the area of implant placement, primarily the reaction of round cell elements. The presence of ifosfamide in the structure of the polymeric implantation material probably affected the proliferation of cellular elements, inhibited regenerative processes in the early stages of the study and delayed the formation of a mature connective tissue capsule around the implanted samples. The tissue culture method showed that when making an extract of isocyanurate-containing polyurethanes with ifosfamide in the culture medium, there was a large variability of cell forms, which led to the appearance of macrophage-like elements.

Modeling of Mechanical Properties of the Polymeric Composite Reinforced with Braided Preform

Braided composite structures based on preforms are widely used in various industries. Owing to use of such preforms high speed and efficiency of the process of manufacturing of polymeric composite materials and structures on their basis can be provided. Knowledge of their properties in the design allows optimizing the production of structures with the specified parameters. The paper gives the review of three approaches to the description of physical and mechanical characteristics of the composite with braided fixtures – based on the classical theory of layered media, rod-based model, and the method of polynomial approximation. The necessary estimated dependencies were derived in order to predict the elastic and structural behavior of the composites under study at any reinforcement angle according to the known characteristics of predetermined angles. Synthesized design parameters, as distinct from the existing ones, allow predicting strength characteristics of the composite based on the braided hoses depending on the positioning and location of the material on the shape-generating surface. For the verification of theoretical results, a number of experimental studies have been carried out with the formation of samples of the material with the different reinforcing angles. Comparison of the analytical and experimental results allows drawing the conclusions that rod-based model gives the best results for the description of elastic behavior of the polymeric composite materials, whereas the obtained polynomial dependences are recommended for the structural behavior. The results of the work represent the basis for solving the problems of calculation of strength of the structures made of composite materials based on the braided preforms

RESEARCH OF POSSIBILITY OF APPLICATION OF FIREPROOF PASTE FOR INCREASE OF FIRE SAFETY OF DESIGNS FROM POLYMERIC COMPOSITE MATERIALS

Possibility of increase of fire safety of VPS-58 glass fibre plastics and carbon fiber-reinforced plastic the VKU-51 brands by putting fireproof swelling-up fireproof paste of the VZO-9kh brand is investigated. Complex researches of physicomechanical, fire and heatphysical properties of fireproof paste of the VZO-9kh brand are conducted. By results of researches it is established that fireproof paste of the VZO-9kh brand corresponds to qualifying standards and can be applied to increase of fire safety of designs from polymeric composite materials.