Jute and Flax Based Biodegradable Composites for High Power Amateur Rocket Structural Applications

摘要

Sounding and high power rockets used in research and amateur hobby generally use various forms of fiberglass and carbon fibers as composite structural materials. Sounding rockets tend to be "fire and forget" as the rocket structure is not recovered after flight and deposited in the ocean or uninhabited terrain. Amateur rocketry also has a number of launch vehicles which are lost and not recovered. The synthetic materials do not biodegrade at a rapid rate and can pose an environmental risk to ocean and land animals from the leaching of toxic compounds. Use of bio-fibers such as jute and flax have been shown to work as structural materials for such applications, have similar strength-to-weight ratios as E-glass, and will biodegrade rapidly when not recovered for reuse. Hence, it this study, natural woven fabrics made of jute and flax fibers in the form of standard burlap cloth are considered as candidate materials. Applied Poleramic? SC-15? epoxy resin (cycloaliphatic amine hardener), Ashland? Envirez 1807? soy-based polyester resin, and waste wood flour produced through mechanical milling of medium density fiberboard were the resin systems and filler material used in the study. In such a study, several aspects need to be addressed in the fabrication to overcome inherent drawbacks of natural fibers which include water absorption, variations in fiber thickness and dimension, and excess fiber weight due to the presence of lignin, pectin, and hemicellulose. Materials properties were characterized by determining tensile, compressive and flexure strengths and stiffnesses for design calculations. In addition, thermo-mechanical characterizations were carried out through differential Scanning Calorimetry (DSC) tests to determine the degree of cure, dynamic mechanical analysis (DMA) to determine the storage and loss modulus, and thermal gravimetric analysis (TGA) to determine the moisture level of the fiber during fabrication for each component. A 12.5 cm diameter, three fin design rocket was designed and developed and flight tested for a design altitude of 1 mile. The flight vehicle was required to meet mandatory structural criteria as other flight vehicles in the competition of NASA's University Student Launch Initiative (USLI) program managed by Marshall Space Flight Center (MSFC) in Huntsville, Alabama. It was also required to meet same stringent safety aspects as any flight vehicle processed by MSFC.