Developments in Phosphorous Compounds as Nonflammable Additives in Different Applications

open_access
Open Access
Author:
Eustis, Benjamin
Area of Honors:
Chemical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
Harry R Allcock, Thesis Supervisor
Wayne Roger Curtis, Thesis Honors Advisor
Keywords:
Organophosphates
Polyphosphazenes
Lithium-ion batteries
PMMA
Flammability
Organic chemistry
Abstract:
Phosphorous compounds have been known to be flame retardants since the nineteenth century. There are many applications where flammability is an undesirable property of a material being used and can potentially lead to safety hazards. One of these hazards occurs in lithium-ion batteries, where organic carbonates are used as solvents in electrolytes to keep viscosity low and conductivity high. However, carbonates are volatile and flammable compounds, showing flash points around room temperature, which can present safety hazards by potential ignition or leaks. As a substitute, solid electrolytes may be used to mitigate the safety hazards associated with liquid electrolytes, but they are plagued by lower conductivity. Organophosphates can be added to these polymer electrolytes to improve conductivity while also maintaining low flammability and volatility. This thesis will review the synthesis of multiple organophosphates and their performance in electrochemical environments. Phosphorous-containing compounds may also be used as an anti-flammable additive to polymers. Poly(methyl methacrylate) (PMMA) is used in windows for its optical properties, but can present safety hazards due to its flammability. Polyphosphazenes, polymers with an alternating phosphorous and nitrogen backbone, can be used as an anti-flammable additive for this material, given that they can match PMMA’s refractive index. Through a series of syntheses, purifications, and analyses via nuclear magnetic resonance, a suitable material may be synthesized for this application.