I'm trying to understand the crystal forms of PET (like alpha, beta) and their corresponding melting temperatures. I've done extensive and in-depth research but couldn't find anything so far. As I see, it's all about XRD and trans-cis conformations.
Dear Esra Ozdemir, many documents are available on the web. These links deal with the crystallization of PET. My Regards
https://www.researchgate.net/publication/290429725_Crystallization_Behavior_of_PET_Materials
https://doi.org/10.1080/15321799508014598
https://doi.org/10.1002/app.1987.070340108
https://doi.org/10.1002/pen.760311202
Dear Esra,
You may have differences in PET; they are accessible by XRD and DSC.
DSC scans shown that crystallization of PET is affected by the heating rate and by the addition of even small amounts of polystyrene. In particular, the rate of cold crystallization of PET is significantly reduced by the incorporation of 1% of polystyrene, attributed to the anti-nucleating effect on PET. Depending of the additives, you may end up with different materials, even polymorphs.
The final product is straightly related to the production pathway.
The suppliers try to fulfill a reasonable industrial need, to know the structure of their product, by reproducing, in some sense, the final product by severe synthetic control of the involved polymerization and poly-condensation.
The oligomers are also tightly controlled. They are poly-esters so that they can be melted and remolded.
As in the PVC industry, a plastic adhesive is the primary contaminant of PET production. The chain may be oriented in the synthetic process to result in a more resistant and transparent product.
In the same way, heat treats the PET may result in final improvements, like higher stability, since tension is reduced all over.
Best regards,
WNM
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