Polyvinyl Acetate Resin as a Binder Effecting Mechanical and CombustionProperties of Combustible Cartridge Case Formulations

Study on GAP Adhesive-Based Polymer Films, Energetic Polymer Composites and Application

To lay the foundation for environmentally friendly energetic polymer composites, GAP (glycidyl azide polymer) adhesive-based polymer films with different curing parameter R (mol ratio of hydroxyl/isocyanate) and energetic polymer composites with different RDX contents were studied. GAP/TDI (toluene diisocyanate)/GLY(glycerol) was selected as the adhesive system. The tensile strength and elongation at the break of the polymer film with R = 2.2, was 14.34 MPa and 176.86%, respectively, as observed by an AGS-J electronic universal testing machine. A relatively complete cross-linking network and high hydrogen bonding interaction were observed by LF-NMR (low-field nuclear magnetic resonance, where the cross-linking density was 11.06 × 10^-4 mol/cm³) and FT-IR (fourier transform infrared spectroscopy, where the carbonyl bonding ratio was 64.84%). Forty percent RDX(hexogen) was added into the adhesive system. The tensile strength was 4.65 MPa, and the elongation at the break was 78.49%; meanwhile, the heat of the explosive was 2.87 MJ/kg, and the residue carbon rate was only 2.47%. The tensile cross-sections of energetic polymer composites were observed by SEM (Scanning electron microscopy).

Design and Development of False Ceiling Board Using Polyvinyl Acetate (PVAc) Composite Reinforced with False Banana Fibres and Filled with Sawdust

This work deals with design and development of false ceiling board from polyvinyl-acetate (PVAc) composite reinforced with false banana fibres and filled with sawdust. The aim was to develop a light weight and good strength performance false ceiling board using raw materials that are fully biodegradable including sawdust, thus solving the problem of its disposal. The false banana fibres were characterized for its tensile strength, elongation, and moisture content since these parameters affect the composite properties. Hand lay-up method combined with compression molding followed by curing was utilised in the manufacture of the false ceiling composites. The optimum proportions of the raw materials were identified using central composite design software, and the results were 40% sawdust, 40% binder (PVAc), and 20% fibres. The mechanical properties of the developed composite board were evaluated in terms of its tensile strength, flexural strength, and compressive strength. In addition, the composite physical properties were also evaluated including its density and moisture absorption. The optimum results obtained were tensile strength of 12.54 N/mm2, compressive strength of 7.03 N/mm2, and flexural strength of 5.13 N/mm2.

Prospective Symbiosis of Green Chemistry and Energetic Materials

A global increase in environmental pollution demands the development of new "cleaner" chemical processes. Among urgent improvements, the replacement of traditional hydrocarbon-derived toxic organic solvents with neoteric solvents less harmful for the environment is one of the most vital issues. As a result of the favorable combination of their unique properties, ionic liquids (ILs), dense gases, and supercritical fluids (SCFs) have gained considerable attention as suitable green chemistry media for the preparation and modification of important chemical compounds and materials. In particular, they have a significant potential in a specific and very important area of research associated with the manufacture and processing of high-energy materials (HEMs). These large-scale manufacturing processes, in which hazardous chemicals and extreme conditions are used, produce a huge amount of hard-to-dispose-of waste. Furthermore, they are risky to staff, and any improvements that would reduce the fire and explosion risks of the corresponding processes are highly desirable. In this Review, useful applications of almost nonflammable ILs, dense gases, and SCFs (first of all, CO₂ ) for nitration and other reactions used for manufacturing HEMs are considered. Recent advances in the field of energetic (oxygen-balanced and hypergolic) ILs are summarized. Significant attention is paid to the SCF-based micronization techniques, which improve the energetic performance of HEMs through an efficient control of the morphology and particle size distribution of the HEM fine particles, and to useful applications of SCFs in HEM processing that makes them less hazardous.