Date of Award

1993

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

First Advisor

William H. Daly

Abstract

Alternating copoly(bis-phenol-co-2,2,4,4-tetramethyl-1,3-cyclobutane) carbonates are synthesized from 2,2,4,4-tetramethyl-1,3-cyclobutanedichloro-formate and the corresponding bis-phenol using a solution polymerization technique. The bis-phenols consist of various 4,4$\sp\prime$-substituted diphenols including: 2,2-propane; 1,1-cyclohexane; 1,1-(4-t-butyl)cyclohexane; 2,2-tricyclo (3.3.1.1) decane; 2,2-bicyclo (3.2.1) heptane; 1,1-(1-phenyl)ethane; 2,2-hexafluoropropane; carbonyl; 9,9-fluorene; sulfide; sulfone; and diphenyl-methane. Crystal structures of the 9,9-tricyclo (3.3.1.1$\sp{3,7}$) decane and 1,1-(4-t-butyl)cyclohexane bis-phenols, previously unreported in the literature, confirm the structures proposed and reveal that the compounds are solvated with acetonitrile and toluene, respectively. The copolymers are isolated by precipitation in methanol; yields ranging from 50 to 80% are obtained. All monomers and polymers reported are characterized by $\sp1$H and $\sp{13}$C NMR and Fourier transform infrared spectroscopy, differential scanning calorimetry, and gel permeation chromatography. The spectroscopic results are consistent with the assigned structures. With the exception of the copolymer with the 2,2-tricyclo(3.3.1.1.) decane substituent, sufficiently high molecular weights are achieved to allow production of stable films by either solution casting or melt pressing. The films are optically clear and show no birefringence when viewed through a crossed polarized microscope. The refractive index varies from 1.49 for the 2,2-hexafluoropropane substituted copolymer to 1.57 for the 9,9-fluorene substituted copolymer; thus, all of the copolymers exhibit lower refractive indices than the bisphenol A homopolycarbonate. The glass transition temperatures vary from 110$\sp\circ$C for the sulfide substituted copolymer to 210$\sp\circ$C for the 9,9-fluorene substituted copolymer. Clearly increasing the bulkiness of substituents in the bis-phenol units is an effective method for raising the glass transition of the copolymers. When heated above their glass transition temperature, the copolymers degrade by a chain unzipping mechanism. The thermal stability is enhanced by end capping the copolymers with chlorotrimethylsilane.

Pages

109

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