Effect Of Different Parameters On Tensile Properties Of Polymeric Matrices Used In Composite Solid Rocket Propellant

Abstract
Glycidyl azide polymer (GAP) and hydroxyl terminated polybutadiene (HTPB) have been evaluated for use as binder for solid propellants. Characterization of the used prepolymers (GAP & HTPB) by employing the possible means to examine their :,Density (Densimeter) , Characteristic groups and IR spectrum by Fourier transformation infrared (FTIR),Nitrogen content (CHN 240), Viscosity (viscometer) ,Humidity ( using Karl-Fisher) and Milligram equivalent (OH)/ Milligram binder (By Titration) . The effects of various parameters like cross-linking conditions, concentration of crosslinker, and the ratio of isocyanate to hydroxyl functional groups (NCO/OH ratio) on the mechanical properties were studied in detail , by preparation of different cross-linked GAP network and cross-linked HTPB network binder formulations using selected materials, From survey it was observed that GAP based binders have poor mechanical characteristics compared with HTPB binders ,So GAP functionality must be raised by the addition of triol ( trimethylol propane (TMP)) to generate the desired extended polymeric matrix, also using a curing catalyst dibuthyltin dilaurate (DBTDL),to ensure curing completion ,the NCO/OH ratio was varied from 0.7 to 1.5, keeping the crosslinker content at 5% with respect to binder (for GAP only), The GAP based specimens were also prepared with cross-linker content varying from 3–9% by weight with respect to binder, keeping the NCO/OH ratio constant at 1, Stress-strain relation for the prepared samples were measured to evaluate the effect of crosslinker, and the ratio of isocyanate to hydroxyl functional groups (NCO/OH ratio) on the mechanical properties to perform the comparison between them from curing & mechanical behavior point of view .