Abstract
The influence of tris(2,3-epoxypropyl) isocyanurate as a bonding agent on viscoelastic dynamic modulus of carboxyl- terminated (butadiene-co-acrylonitrile)-based composite propellant was investigated. Strain amplitude sweep tests have been run at the room temperature. Frequency dependencies of rheological behaviour parameters (storage and loss modulus) were also analyzed. Based on the frequency dependencies of the storage and loss modulus, in the temperature range from -80 °C to 40 °C, the master curves were created, reaching broader frequency interval in comparison to that used in the measurements. This enables a prediction of the material response at various frequencies, usually unobtainable experimentally. Williams- Landell-Ferry (WLF) equation constants were determined for different reference temperatures. Further, material constants, fractional free volume at the glass transition temperature and thermal coefficient of free volume expansion were calculated. The data obtained from WLF analysis of the tested composite propellants showed that the values of the thermal coefficient of expansion of free volume and the fractional free volume at the glass transition temperature decrease with increasing content of tris(2,3-epoxypropyl) isocyanurate. Also, the apparent energy for viscoelastic relaxation increases, because of the increased intermolecular hydrogen interactions.
Highlights
COMPOSITE solid rocket propellants consist of solid rigid fillers embedded in a rubbery polymeric matrix [1,2]
The polyurethane network obtained by curing Hydroxyl–terminated poly(butadiene) (HTPB) with a suitable diisocyanate provides an adequate polymeric matrix for inorganic oxidizer and metallic fuel that are dispersed in the propellant grain
The Dynamic mechanical thermal analysis (DMTA) tests, in order to evaluate the influence of TEIC on rheological properties of tested composite propellants, have included the strain sweep and frequency sweep tests
Summary
COMPOSITE solid rocket propellants consist of solid rigid fillers (usually ammonium–perchlorate) embedded in a rubbery polymeric matrix [1,2]. The binder, as the name implies, holds the composition together and acts as an auxiliary fuel. The polyurethane network obtained by curing HTPB with a suitable diisocyanate provides an adequate polymeric matrix for inorganic oxidizer and metallic fuel that are dispersed in the propellant grain. Mechanical properties of these materials are related to the macromolecular structure of the binder as well as to the content and nature of the fillers [4]. As dewetting is the main damage mechanism in composite rocket propellants, bonding agents are added to the composition to promote the adhesion
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
