Date of Award
Doctor of Philosophy
Chemical and Biological Engineering
The investigational work was divided into two parts. In the first part, information was obtained as to the nature of the reactions of the individual constituents of high pentosanocellulosic materials with phenol or the cresols in the presence of a catalyst;Cellulose was found to act in two ways; it would either dissolve in phenol and zinc chloride, the zinc chloride acting as a solvent instead of catalyst, or it would undergo decomposition and condense with phenol to form a black, resinous material. Sulfuric acid served also as catalyst in the condensation, while sodium hydroxide did not. The presence of the condensation products of cellulose and cresol was found to exert a retarding action on the condensation and polymerization of a cresol-furfural mixture;The pentosans were found to be soluble in phenol and cresol without reaction or, at an elevated temperature and in the presence of sulfuric acid, they would condense similarly to cellulose to give a resinous material;Xylose would also condense with phenol like the pentosans, but at a somewhat lower temperature;Lignins were not directly soluble in phenol but would dissolve with condensation to give a tarry liquid which remained fluid after considerable heating;In the second part of the experimental work, a steam pressure cooker and an electrically-heated reaction vessel were adapted for carrying out the reaction between corncobs or oathulls and cresol;A standard process was developed for carrying out the reaction, and for preparing a molding compound from the plastic material. This process consisted of the following: (1) Five parts by weight of H2SO4 were dissolved in an equal weight of water and then combined with 100 parts of cresol. (2) The solution was heated to boiling in an autoclave and 30 parts of ground corncobs introduced gradually. (3) The autoclave was closed and the temperature kept at 140 deg. C for 3 hours. (4) The pressure was then released and a vacuum distillation carried out to remove excess cresol and other volatile materials. (5) When the distillation temperature had reached 250--300 deg. C, the residual liquid was run into flat pans and cooled until solid. (6) The solid resin was ground to pass a sixty mesh sieve and then incorporated with 55 percent wood flour filler to produce the molding compound;The properties of the molding compound were improved by a study of the effect of the molding temperature; by experiments with the use of plasticizers; by an investigation of various fillers, and through experiments on the effect of paraformaldehyde and hexamine as hardening agents.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
William Donald Harris
Harris, William Donald, "Plastics from high pentosanocellulosic material " (1934). Retrospective Theses and Dissertations. 13511.