III International Conference

PP-III-22MODIFICATION OF COMPOUNDED RUBBERS WITH LIQUID POLYKETONESemikolenov S.V., Dubkov K.A., Ivanov D.P., Voronchikhin V.D. 1 , Ershov D.V. 1 , Panov G.I.Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia1 Siberian State Technological University, Krasnoyarsk, RussiaE-mail: sersem@catalysis.ruEffect of a low-molecular polyketone (Mn = 2200, oxygen content 9.9 wt %) addition onthe properties of compounded rubbers obtained with polybutadiene (SKD) or nitrile-butadienepolymer (BNKS) was studied. Polyketone was prepared via carboxidation of polybutadieneby N 2 O. The addition of polyketone into SKD-rubber decreases abradability and mechanicallosses. When polyketone is introduced into BNKS-rubber, this increases tear strength andfrost resistance, and decreases the rate of rubber ageing. Other physico-mechanical propertiesof vulcanized rubbers remain virtually unchanged. Polyketone addition is considered to be apromising method for improving the performance of these type rubbers.Recently, a method of synthesizing new functional oligomers containing carbonyl groupshas been developed at the Boreskov Institute of Catalysis SB RAS. The method consists intreatment of unsaturated polymers containing double C=C bonds with nitrous oxide (N 2 O) attemperature 180–230°C and pressure 30–80 atm (the so-called carboxidation). The reactionproceeds via non-catalytic 1,3-dipolar cycloaddition of N 2 O to C=C bonds accompanied bythe formation of C=O groups in the polymer backbone. The carboxidation of cis-1,4-polybutadiene SKD (M n = 128000) can be presented by the following scheme [1]:NO1N OCH 3 -C+ NCH=CH 2 O~95%CH-CH-N 2 2O=CH 2 + C~5%HMain route (95%) of the reaction proceeds without cleavage of C=C bonds and leads to theformation of ketone groups in the polymer backbone. A minor route (5%) of the reactionproceeds with the cleavage, yielding smaller fragments containing aldehyde and vinyl endgroups. This may lead to a dramatic decrease in the molecular weight, which, depending onthe carboxidation degree, may be 1–2 orders of magnitude less than that of the parentpolymer. The carboxidation of more than 15% of the polybutadiene C=C bonds transforms itinto a C=O functionalized liquid oligomer having quite a narrow molecular-weightdistribution (M w /M n ≈ 2). The materials obtained are unsaturated polyketones containingdouble C=C bonds, (>C=O) groups, and aldehyde and vinyl end groups.509