DMA

— This paper is about the fabrication and testing of banana fiber eco-friendly carry bag. Now a day the government banned the plastics bags by 2019. In our project we are try to change the material of the carry bag by banana fiber. This will help to keep the environment healthy and pollution free. By implementing our project we can reduce the usage of the plastics and keep the world away from the plastics. Natural fibers are best in both cost savings and low in density when compared to glass fibers. They are grown steadily in many applications. A natural fiber is a resource to synthetic fibers, as reinforcement for polymeric materials for the manufacture is very cheap, renewable and environment friendly.

The effect of time and temperature on the mechanical properties of an extruded wood–polypropylene composite (WPC) material was investigated. Polyvinyl chloride (PVC) material, acquired from commercially available sheet piles, was adopted to establish the baseline performance for structural applications. Quasi-static and creep tensile tests were conducted at −10, 21, 30, 45 and 65 °C. The decrease in the modulus of elasticity and the modulus of rupture with the increase in temperature was characterized. Short-term tensile creep tests were conducted for 40% stress level at 21, 30 and 45 °C. The time–temperature superposition principle was implemented to model the long-term creep performance at 21 °C. The long-term creep response was predicted up to 7.9 years for the WPC material. The WPC material long-term creep prediction was validated by correlating the fractional deflections with experimental values obtained from long-term creep tests previously conducted for the same material formulation.

This study aims to evaluate the dynamic mechanical properties of a binder, used in composite propellants, with increasing amount of different solid fillers. Dynamic Mechanical Analysis (DMA) is performed to determine the region of glass-rubber transition temperature (T g). Further parameters were obtained from the description of the loss factor curves (tanδ) with models based on exponentially modified Gauss (EMG) distribution function. Polyurethane binders employing the polyol HTPB and diisocyanate were filled with 20, 40, and 60 mass-% of ammonium perchlorate (AP), aluminum (Al) or cyclotrimethylene trinitramine (RDX) particles, using fine and coarse mean sizes. A special turning device manufactured by Fraunhofer ICT was installed inside the curing oven in order to avoid sedimentation during curing. The cured composites were characterized by DMA in torsion mode from-100 °C to 70 °C. The good homogeneous distribution of fillers in the samples was evaluated by computational X-ray micro-tomography. The data on tanδ showed a complex structure describable at first with 2 overlapping peaks. The peak at lower temperatures is due to mobility of unrestricted binder parts (T g unr) and the second broader peak at high temperature is due to mobility of restricted binder parts (T g res). Results of tanδ, calculated areas of EMG curves and apparent activation energies of the distinct relaxation processes indicate that Al particles have higher interaction with HTPB-based polyurethane than AP and RDX. Probably Al is bonded to the binder network via isocyanate coupling with OH groups present in the surface. Ammonium perchlorate and cyclotrimethylene trinitramine particle sizes and its morphology influenced the viscoelastic properties. AP and RDX cause more changes in intensity of first peak of loss factor than Al. Increasing amount of these both particles enhances storage (G') and loss (G ") shear moduli. As a whole tanδ intensity is lowered in the main peak and Al showed an intensity increase in the second apparent peak.