Physical ageing in semi-crystalline polyethylene terephthalate

Nicholls, David (2010). Physical ageing in semi-crystalline polyethylene terephthalate. University of Birmingham. M.Res.

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Abstract

The polymer industry is growing at an extremely large rate and with the recycling of plastics and polymers from packaging and containers at an all time high, there is a greater need to understand the physical elements that affect the structure of these polymers. There has been much previous work in the field of crystallisation, glass transition and polymer ageing. Many scientists have studied their findings on the work of L.C.E Struik who led the way in polymer science. However, there has been, as far as research shows, no work on Polyethylene Terephthalate (PET) and the effects ageing can have on this polymer. Two sets of testing were performed, the first on a Thermo-mechanical Analyser (TMA) and the second on a Differential Scanning Calorimeter (DSC). The glasstransition temperatures and physical ageing effects were tested on the TMA, whilst on the DSC, only the physical ageing effects were tested. During the ageing experiments 3 samples of varying crystallinity were created, one sample was completely amorphous (0% crystalline), the other samples were 28% crystalline and 65% crystalline. The results showed that physical ageing can take place in PET. The definitive conclusion is that as the crystallinity increased the amount of ageing decreased. This shows that physical ageing primarily affects the amorphous regions of polymers; it is here that there is no organisation within the microstructure giving molecules larger areas of free volume to occupy.

Type of Work:

Thesis (Masters by Research > M.Res.)

Award Type:

Masters by Research > M.Res.

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