Abstract
The production of artificial polymers with a complex of useful physical and chemical properties is based on three main methods of their synthesis is polymerization, polycondensation and modification. At the same time, the modification of polymers has now found wide application, including for the production of cellulose ethers, among which cellulose nitrate ester is one of the large-scale products. Through reactions of functional groups, cellulose nitrate can be converted into new compounds in nucleophilic substitution reactions. The interaction of 4,4',5,5'-Tetranitro-2,2'-bi-1H-imidazole (TNBI) with cellulose nitrate C6H7O2(OH)0,87(ONO2)2,13 in the medium of dimethylformamide at a temperature of 70-72 oC and different reaction times 1, 2, 3 and 4 hours was studied. The main directions of the reaction were identified, namely, nucleophilic substitution nitrate groups of cellulose nitrate for a fragment of a THБИ; partial hydrolysis of nitrate groups; depolymerization and destruction of the polymer chain with the breaking of β-glycosidic bonds and joining at the ends of the polymer chain in the positions C1 and C4 of the fragment of a TNBI molecule. Based on the results of experimental data and physical and chemical studies, the chemical composition and structure of the reaction products obtained are determined and the scheme of interaction of cellulose nitrate with TNBI is presented. It was found that the product of interaction of cellulose nitrate with TNBI, obtained at the maximum reaction time 4 hours at a temperature of 70 oC has the lowest degree of substitution of nitrate groups. A further increase the reaction time does not lead to a significant increase in the content of the TNBI fragment in the products, since there is a strong degradation of the initial polymer, which makes it difficult to isolate high-molecular products was found. The possibility of a directed change in the composition of chemically modified cellulose nitrates at different stages of synthesis to obtain products with controlled composition and properties has been established.
Published Version
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