Surface properties of poly(bisphenol-A-carbonate)

Weerapperuma, D. G. Kamal E. (1981). Surface properties of poly(bisphenol-A-carbonate). PhD thesis The Open University.



The work presented in this thesis consists of several strands:

(a) the development of a technique to measure surface free energies of amorphous polymers
(b) an investigation of chemical polishing and
c) the problems of injection moulded polycarbonate.

Grooves inscribed in an amorphous polymer surface change in dimensions on thermal annealing, and this change observed by interferometry forms the basis of the surface free energy measurement technique. Stringent temperature control and accurate temperature monitoring during thermal annealing is an essential feature of this technique. A surface free energy of approximately 0.121 J m-2 (121 ergs cm-2) at 174°C was measured for polycarbonate using this method.

An increase in the polishing temperature the thinning rate but not the extent of polishing position of the sample during polishing was found rate of the viscous layer and hence polishing and was found to increase or etching. The to affect the growth etching phases. An activation energy of 26.0 kJ (mol)-1 was measured for the thinning process.

A high degree of molecular orientation and residual stress (a major reason for premature mechanical failure) was primarily attributed to cold moulding and poor mould design coupled with inadequate testing of, the finished product. The high birefringence observed in the moulding was predominantly attributed to molecular orientation and residual stress.

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