Microwave Accelerated Methanolysis of Poly(ethylene terephthalate)

Order Of Magnitude ◽

Poly(ethylene terephthalate) (PET) is an important commodity polymer that has the potential to be 100% recycled, but this is currently not economically viable as the costs of recovering the starting materials are greater than virgin materials. As well as PET, there are a number of other interesting poly(terephthalate)s which have higher economic value. However, for many of these, virgin material is necessary to avoid contamination with ET units. This can be avoided by chemically deconstructing the PET to simple terephthalates. In this work, we show that dimethyl terephthalate (DMT) can be easily obtained from PET, in high purity (> 99.5% for the crude) with a relatively low energy use (ca. 0.3 Mj.g-1), by using a microwave reactor. In a microwave reactor the methanolysis proceeds an order of magnitude faster than in a conventional reactor. This is apparently due to cavitation caused by hot-spots, which break up the PET, increasing the active surface, and an increased population of PET particles above the Ea in the hot zones.

Recycling of poly(ethylene terephthalate) waste through methanolic pyrolysis in a microwave reactor

Journal of Analytical and Applied Pyrolysis ◽

10.1016/j.jaap.2012.09.007 ◽

2012 ◽

Vol 98 ◽

pp. 214-220 ◽

Cited By ~ 33

Author(s):

Mohammad Nahid Siddiqui ◽

Halim Hamid Redhwi ◽

Dimitris S. Achilias

Keyword(s):

Ethylene Terephthalate ◽

Microwave Reactor ◽

Aminolytic depolymerization of poly(ethylene terephthalate) waste in a microwave reactor

Polymer International ◽

10.1002/pi.2976 ◽

2010 ◽

Vol 60 (3) ◽

pp. 500-506 ◽

Cited By ~ 41

Author(s):

Dimitris S Achilias ◽

Georgia P Tsintzou ◽

Alexandros K Nikolaidis ◽

Dimitris N Bikiaris ◽

George P Karayannidis

Keyword(s):

Ethylene Terephthalate ◽

Microwave Reactor ◽

Morphology optimization of poly(ethylene terephthalate)/polyamide blends compatibilized via extension-dominated twin-screw extrusion

Journal of Polymer Engineering ◽

10.1515/polyeng-2020-0229 ◽

2021 ◽

Vol 41 (3) ◽

pp. 218-225

Author(s):

Hao Chen ◽

Molin Guo ◽

David Schiraldi ◽

João M. Maia

Keyword(s):

Droplet Size ◽

Ethylene Terephthalate ◽

Aromatic Polyamide ◽

Twin Screw Extrusion ◽

Immiscible Polymers ◽

Screw Extrusion ◽

Twin Screw ◽

Order Of Magnitude ◽

Abstract Poly(ethylene terephthalate) (PET) and polyamide (PA) are immiscible polymers, which requires the use of compatibilizers to stabilize the morphology and achieve acceptable property levels. Therefore, controlling the degree of dispersion, especially the size of the disperse PA droplets in the PET matrix is of paramount importance. This study aims to improve the mixing, i.e., minimize PA droplet size, in immiscible and compatibilized PET/PA and PET/Nylon-MXD6 (MXD6) blends by resorting to extension-dominated mixing in twin-screw extrusion (TSE). MXD6 is an aromatic polyamide similar in polarity to PET, so it is expected that it will blend more effectively than is the case with aliphatic nylon-6 and PET. Two screw configurations are used, a benchmark shear-dominated screw with kneading blocks (KBs) in an aggressive configuration, and an extension-dominated screw configuration with static mixers with hyperbolic C–D channels, recently developed by our group, in place of the KBs. The results show that the use of extensional mixing elements (EMEs) in place of KBs results in a significant decrease of both average and maximum droplet size for all blends, and up to more than one order of magnitude between the most extreme cases of the KB-processed immiscible blend and EME-processed compatibilized blends.

Construction and demolition waste as a source of PVC for recycling

Waste Management & Research ◽

10.1177/0734242x11413329 ◽

2011 ◽

Vol 30 (2) ◽

pp. 115-121 ◽

Cited By ~ 6

Author(s):

Sabrina Moretto Darbello Prestes ◽

Sandro Donnini Mancini ◽

Antonio Rodolfo ◽

Raquel Carramillo Keiroglo

Keyword(s):

Ethylene Terephthalate ◽

Ash Content ◽

Construction And Demolition Waste ◽

Particle Sizes ◽

Virgin Material ◽

Demolition Waste ◽

Application Potential ◽

Poly Ethylene ◽

Recycled Material

Construction and demolition waste can contain considerable amounts of polyvinyl chloride (PVC). This paper describes a study of the recycling of PVC pipes collected from such waste materials. In a sorting facility for the specific disposal of construction and demolition waste, PVC was found to represent one-third of the plastics separated by workers. Pipes were sorted carefully to preclude any possible contamination by poly(ethylene terephthalate) (PET) found in the waste. The material was ground into two distinct particle sizes (final mesh of 12.7 and 8 mm), washed, dried and recycled. The average formulation of the pipes was determined based on ash content tests and used in the fabrication of a similar compound made mainly of virgin PVC. Samples of recycled pipes and of compound based on virgin material were subjected to tensile and impact tests and provided very similar results. These results are a good indication of the application potential of the recycled material and of the fact that longer grinding to obtain finer particles is not necessarily beneficial.