Abstract: The subject of the invention is a detonation rocket engine comprising an annular detonation chamber (5) connected to the Aerospike nozzle (4) and lines (2, 3) for supplying propellant components connected to the detonation chamber (5). The detonation chamber (5) has a bottom (9) connecting the inner wall (10) and the outer wall (11) between which the outlet (6) is formed. At the outlet (6) of the detonation chamber (5) there are at least three evenly distributed centring elements (1) connecting the inner wall (10) and the outer wall (11) of the detonation chamber (5), with cooling channels (7) connected to one of the lines (2, 3) supplying the propellant components to the detonation chamber (5).

Abstract: The present invention relates to a process for producing polyhydroxyalkanoate oligomers and/or polymers of reduced molecular weight, which comprises reacting at least one polyhydroxyalkanoate (PHA) with at least one carbonate salt at a temperature of from 50° C. to 300° C., preferably from 120° C. to 200° C. The above reaction allows a controlled degradation of the PHA chains which yields oligomers and/or polymers having a controlled molecular weight, which can be modulated in view of the specific application for which the oligomers and/or polymers are intended. Moreover, during the reaction carbon dioxide evolves which produces a foamed material which can be easily processed on an industrial scale.