The influence of phosphorus fire retardant reactives on the thermal degradation of polyurethane

Mackerron, Duncan Henry (1981) The influence of phosphorus fire retardant reactives on the thermal degradation of polyurethane. PhD thesis, University of Glasgow.

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The object of this work was to prepare some polyurethanes which contained phosphorus and to observe the major features of their thermal degradation. If the mechanism of thermal degradation was revealed some fundamental reasons for the flame retardant properties of phosphorus might become evident. Chapter 3 describes how phosphorus was incorporated in the backbone chain of the polyurethanes by copolymerisation of linear polyesters of phosphoric and phosphonic acids with methylene bis(4-phenylisocyanate) (M.B.P.I.) and the chain extender 1,4-butanediol (B.D.). Four polyurethanes, P.D.I, P.D.2, P.D.3 and P.D.4,were prepared using these phosphorus polyesters which had different structures and molecular weights. The polymers were then characterised chemically and spectroscopically and in the case of P.D.I evidence presented to confirm its structure. Before the thermal degradation of the polyurethanes was studied additional information was obtained from thermal analysis of poly- [butylene phenylphosphonateJ, the polyester used to prepare Polyurethane I. The results in Chapter 5 supplement those in literature which describe the thermal degradation of the polyurethane, poly- [butylenemethylene bis(4-phenylcarbamate)] to allow a prediction from first principles of the reaction of P.D.I to heat. Many of the reactions of thermal degradation seen ~n poly- [butylenemethylene bis(4-phenylcarbamate)] and poly[butylene phenylphosphonate] occur in P.D.I; however Chapter 6 also highlights new reactions and interactions which occur in the polymer. Further from the thermal degradation of five samples of Polyurethane I each containing a different proportion of hard segment (M.B.P.I. + B.D.) and polyester it was evident that phosphorus enhances one of three standard mechanisms of decomposition of urethane. In Chapter 7 the effect which small modifications to the structure of the phosphorus polyester in the polyurethane backbone chain have on the overall thermal degradation of the polymer was investigated. Some changes believed to be beneficial to the flame resistance of the polyurethane were noted and the phosphorus, active in the form of an acid during thermal degradation, seen to promote decomposition at lower temperatures.The final chapter has discussed the pure and applied problems of creating and testing non-inflammable plastics. Rather than suggest a solution the author has had to be content to explain the hurdles confronting scientists who are required to predict the performance of polymeric materials using only results from small scale laboratory experiments. Finally suggestions for future work in this field are offered both out of academic interest and as potential areas of practical importance.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Subjects: Q Science > QD Chemistry
Colleges/Schools: College of Science and Engineering > School of Chemistry
Supervisor's Name: Supervisor, not known
Date of Award: 1981
Depositing User: Adam Swann
Unique ID: glathesis:1981-30614
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 04 Jun 2018 15:25
Last Modified: 04 Jun 2018 15:25

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