Theses and Dissertations at Montana State University (MSU)
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Item Biochar as a renewable carbon additive for biodegradable plastics(Montana State University - Bozeman, College of Engineering, 2022) Kane, Seth Douglas; Chairperson, Graduate Committee: Cecily Ryan; This is a manuscript style paper that includes co-authored chapters.Biochar - a carbon material produced from pyrolysis of biomass - is a promising alternative to petroleum-derived filler materials in biobased and biodegradable plastics. In this application, biochar can replace materials such as carbon black, with a material that is compatible with end-of-life degradation of bioplastics, while reducing costs and improving material properties. Specifically, high electrical conductivity biochar has the potential to be applied to create highly electrically conductive and biodegradable biochar-bioplastic composite materials. Herein, two critical gaps to development of biochar-bioplastic composites are addressed: the high variation in biochar electrical conductivity and poor thermal interactions between bioplastics and biochar that reduce the bioplastics molecular weight and mechanical properties. To this end, biochars are produced from a variety of feedstocks and their chemical structure and electrical conductivity are extensively characterized. The relationship between feedstock chemical properties, biochar chemical properties, and biochar electrical conductivity is examined. Feedstock oxygen and inorganic content are found to play a critical role in developing highly electrically conductive biochar. The impact of these biochars on the thermal behavior of bioplastics is then examined in detail, and multiple hypotheses for the reduction in thermal behavior that have been proposed in past studies are tested. Biochar moisture content is found to have a limited impact on polymer thermal degradation, while alkali and alkaline earth metals present in biochar reduce the thermal degradation temperature of common bioplastics. A simple washing method was developed to remove these metals and improve the thermal stability of biochar-bioplastic composites. Finally, the environmental benefits of biochar-plastic composites are examined with life cycle assessment methodology, and the developed biochar is examined as a conductive additive in lithium-ion batteries. This work addresses two critical issues that limited the potential of biochar to reduce environmental impacts of rapidly growing classes of materials, as well as demonstrating its applicability in critical applications of petroleum-derived materials. Biochar-bioplastic composites show a unique combination of high electrical conductivity and biodegradability, with strong potential for development of applications in diverse industries from agriculture to biomedical applications.Item Pyrolysis of thermal protection system materials: molar yields of volatile products derived from in situ mass spectrometric measurements(Montana State University - Bozeman, College of Letters & Science, 2018) Bessire, Brody Kelly; Chairperson, Graduate Committee: Timothy Minton; Sridhar A. Lahankar and Timothy K. Minton were co-authors of the article, 'Pyrolysis of phenolic impregnated carbon ablartor (PICA)' in the journal 'ACS applied materials and interfaces' which is contained within this thesis.; Timothy K. Minton was a co-author of the article, 'Decomposition of phenolic impregnated carbon ablator (PICA) as a function of temperature and heating rate' in the journal 'ACS applied materials and interfaces' which is contained within this thesis.; Timothy K. Minton was a co-author of the article, 'Pyrolysis of epoxy-novolac materials as a function of time and temperature' submitted to the journal 'The journal of analytical and applied pyrolysis' which is contained within this thesis.Mass spectrometric techniques have been developed to measure the molar yields of pyrolysis products from ablative resins and composite materials at heating rates that are relevant to flight conditions. Thermal decomposition mechanisms of phenolic and an epoxy-novolac resin systems are reviewed. New insights into the thermal decomposition mechanisms of PICA (Phenolic Impregnated Carbon Ablator) and epoxy-novolac D.E.N. 438 (Dow Epoxy-Novolac) are proposed and are based on the measurements of molar yields from these materials. Molar yield data have been provided in the appendices of this thesis for use in material response models. The thermal decomposition of phenolic impregnated carbon ablator (PICA) has been investigated with the objective of measuring molar yields of pyrolysis products at heating rates that are relevant to MSL flight conditions. The relative molar yields of 14 pyrolysis gases were obtained in conjunction with mass loss measurements. These measurements allowed for the calculation of absolute molar yields and mass yields as a function of temperature and heating rate, as well as the simulation of TGA curves. Pyrolysis product yields change as a function of heating rate, and this behavior has been attributed to two mechanisms that compete during the initial stages of thermal decomposition. The results of this study are now available for use in material response models. The thermal decomposition of an epoxy-novolac resin system has also been investigated. Samples of D.E.N. 438 were cured using NMA (methyl-5-norbornene-2,3-dicarboxylic anhydride) as a crosslinking agent and BDMA (N-benzyldimethylamine) as a catalyst. A radiative heating method was developed to minimize experimental uncertainties that may emerge from thermal gradients that are established across the samples as they experience high rates of heating. The molar yields of the six dominant pyrolysis products were measured at a heating rate of 8°C s -1. The molar yields of pyrolysis products provide new insight, and a new thermal decomposition mechanism is proposed.Item The pyrolysis of naphthacene(Montana State University - Bozeman, College of Engineering, 1967) Philip, John CharlesItem A kinetic study of the pyrolysis reactions of acenaphthylene and bifluorenyl(Montana State University - Bozeman, College of Engineering, 1966) Currie, Robert AndrewItem A study of the thermal decomposition of 1, 8-dinaphthylenethiophene(Montana State University - Bozeman, College of Engineering, 1967) War, William ThomasItem A study of the thermal decomposition of 2-naphthyl disulfide(Montana State University - Bozeman, College of Engineering, 1969) Kan, George Lan-yuh