Degradation process of low molar mass poly(ethylene terephthalate)/organically modified montmorillonite nanocomposites

2016 ◽  
Vol 30 (4) ◽  
pp. 504-520 ◽  
Author(s):  
Juliana A de Lima ◽  
Lays B Fitaroni ◽  
Daniel VA Chiaretti ◽  
Manuela LQA Kaneko ◽  
Sandra A Cruz
Keyword(s):  
Ethylene Terephthalate ◽  
Molar Mass ◽  
Degradation Process ◽  
Melt Processing ◽  
Platelet Surface ◽  
Modified Montmorillonite ◽  
Organically Modified Montmorillonite ◽  
Poly Ethylene Terephthalate ◽  
Organically Modified ◽  
Poly Ethylene

The aim of this work is to investigate the degradation of low molar mass poly(ethylene terephthalate) (PET)/organically modified montmorillonite (OMMT) clay nanocomposites prepared by melt processing. The rheological behavior in combination with transmission electron microscopic images suggests an intercalation and therefore a percolating network. Furthermore, the results indicate that the increase of organoclay content caused a degradation of PET during processing of PET/OMMT nanocomposites, once it was observed the PET molar mass decreases. The effect mentioned could be attributed to an increase of Brønsted acidic sites on the platelet surface, which is produced by the Hofmann elimination reaction of ammonium, and also the presence of residual metal compounds on clay surface might possibly favored the polymer matrix degradation process.

Effects of Chain Extension and Branching on the Properties of Poly (Ethylene-Terephthalate)-Organoclay Nanocomposites

2004 ◽  
Vol 856 ◽  
Author(s):  
Ali Emrah Keyfoglu ◽  
Ulku Yilmazer
Keyword(s):  
Ethylene Terephthalate ◽  
Interlayer Spacing ◽  
Chain Scission ◽  
Chain Extension ◽  
Twin Screw Extrusion ◽  
Poly Ethylene Terephthalate ◽  
Screw Extrusion ◽  
Organically Modified ◽  
Twin Screw ◽  
Poly Ethylene

ABSTRACTThe effects of chain extension and branching on the properties of nanocomposites produced from recycled poly (ethylene-terephthalate) and organically modified clay were investigated. As the potential chain extension/branching agent, maleic anhydride (MA) and pyromellitic dianhydride (PMDA) were used. The nanocomposites were prepared by twin-screw extrusion, followed by injection molding. Recycled poly (ethylene-terephthalate) was mixed with 2, 3 or 4 weight % of organically modified montmorillonite. During the second extrusion step, 0.5, 0.75 or 1 weight % of MA or PMDA was added to the products of the first extrusion. The effects of the sequence of addition of the ingredients on the final properties of the nanocomposites were also investigated. X-Ray Diffraction analysis showed that, the interlayer spacing of Cloisite 25A expanded from 19.21 Å to about 28–34 Å after processing with polymer indicating an intercalated structure. PMDA content, MA content and screw speed did not have a significant effect on the expanded interlayer distance. In the first extrusion step, nanocomposites containing 3% organoclay content gave significant increase in Young's modulus and decrease in elongation at break values indicating good interfacial adhesion. After the addition of anhydrides, it was observed that, in general PMDA improved the mechanical properties of the nanocomposite owing to the branching and chain extension effects that increase the molecular weight. However, MA did not significantly improve the properties, since in this case the chain scission seemed to be more dominant.

Colour formation in poly(ethylene terephthalate) during melt processing

2006 ◽  
Vol 91 (4) ◽  
pp. 875-885 ◽  
Author(s):  
Calin Flaviu Ladasiu Ciolacu ◽  
Namita Roy Choudhury ◽  
Naba K. Dutta
Keyword(s):  
Ethylene Terephthalate ◽  
Melt Processing ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene

Crystallization Processes In Poly (Ethylene Terephthalate) / Polycarbonate Blends

1993 ◽  
Vol 321 ◽  
Author(s):  
Veronika E. Reinsch ◽  
Ludwig Rebenfeld
Keyword(s):  
Ethylene Terephthalate ◽  
Crystallization Rate ◽  
Melt Processing ◽  
Degree Of Crystallinity ◽  
Processing Temperature ◽  
Scanning Calorimetry ◽  
Processing Times ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
Crystallization From The Melt

ABSTRACTBlends of poly (ethylene terephthalate), or PET, and polycarbonate (PC) over a range of compositions were studied in isothermal crystallizations from the melt using differential scanning calorimetry (DSC). Both crystallization rate and degree of crystallinity of PET depend on blend composition. The glass transition temperature, Tg, of PET and PC in blends and pure polymer were also measured by DSC. Elevation of the Tg of PET and depression of the Tg of PC are observed upon blending. In cooling scans, dynamic crystallization from the melt was observed. In PET/PC blends with high PC content, a novel dual-peak crystallization of PET was observed. The effects of thermal history on crystallization kinetics and degree of crystallinity were also determined in isothermal crystallization studies. For Melt processing times between 1 and 30 Min and for processing temperatures between 280 and 300 °C, Melt processing temperature was seen to have a stronger effect than processing time.

Aromatic-aliphatic copolyesters based on waste poly(ethylene terephthalate) and their biodegradability

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Irena Prokopová ◽  
Eva Vlčková ◽  
Václav Šašek ◽  
Josef Náhlík ◽  
Veronika Soukupová–Chaloupková ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Aqueous Solution ◽  
Lactic Acid ◽  
Ethylene Terephthalate ◽  
Molar Mass ◽  
Amorphous Structure ◽  
Structural Units ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
Physical Degradation

AbstractThe solvolysis of poly(ethylene terephthalate) from disposed beverage bottles by an aqueous solution of lactic acid, followed by the zinc acetate catalyzed polycondensation of the solvolytic product, yielded a series of aromatic-aliphatic copolyesters containing up to 55 mol.% of incorporated lactic acid structural units. Their molecular parameters were determined using SEC and viscometry. According to DSC, the copolyesters have amorphous structure. Selected copolyester samples were subjected to abiotic hydrolysis at pH 7 and 60 °C. After three days of hydrolysis, the mass of the samples decreased substantially and their molar mass was reduced. At 37 °C, strong degradation of copolyesters by action of the actinomycete Rhodococcuserythropolis was observed. Biodegradability of the copolyesters was confirmed by a composting test. In addition to the changes of the molecular structure of the composed samples, the physical degradation of the foils of the samples tested was also documented by SEM.

scholarly journals Effects of melt-processing conditions on the quality of poly(ethylene terephthalate) montmorillonite clay nanocomposites

2002 ◽  
Vol 40 (23) ◽  
pp. 2661-2666 ◽  
Author(s):  
Cher H. Davis ◽  
Lon J. Mathias ◽  
Jeffrey W. Gilman ◽  
David A. Schiraldi ◽  
J. Randy Shields ◽  
...  
Keyword(s):  
Ethylene Terephthalate ◽  
Melt Processing ◽  
Montmorillonite Clay ◽  
Clay Nanocomposites ◽  
Processing Conditions ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene
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