Scanning electron microscopic study of hazardous waste flakes of polyethylene terephthalate (PET) by aminolysis and ammonolysis

Mittal, Alok; Soni, Rakesh Kumar; Dutt, Krishna; Singh, Swati

doi:10.1016/j.jhazmat.2010.01.092

Cited by 84 publications

(45 citation statements)

References 15 publications

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“…The tertiary recycling processes transform waste PET into raw materials that can be reused for manufacturing new products [5,6]. PET waste can be depolymerized by transesterification using various agents, such as water (hydrolysis), acids or bases [7,8], alcohols (alcoholysis) [9][10][11], amines (aminolysis) [12], and glycols (glycolysis) [13][14][15][16]. Raw or purified materials obtained in that way can be used for the synthesis of a polyester resins [17][18][19], epoxy resins [20,21], polyurethane resins [22][23][24], and alkyd resins [25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Effect of the modified silica Nanofiller on the Mechanical Properties of Unsaturated Polyester Resins Based on Recycled Polyethylene Terephthalate

et al. 2015

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Unsaturated polyester resin (UPe)-based nanocomposites and fumed silica Aerosil R812S, R805 and R816, and R200 modified with phenyl terminal group, R200NPh, were prepared. UPe resins were synthesized from maleic anhydride and products of glycolysis, obtained by polyethylene terephthalate depolymerization with dipropylene glycol in the presence of tetrabutyl titanate catalyst. The obtained unsaturated polyesters were characterized by acid, hydroxyl, and iodine values and by FTIR and NMR analysis. The microstructural analysis of the prepared nanocomposites, performed by using transmission electron microscopy, confirmed that silica nanoparticles formed chain-like aggregates in the polymer matrix. The presence of modified silica nanoparticles had no influence on the glass transition temperature and thermal stability of polyester matrix.

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Section: Introductionmentioning

confidence: 99%

Effect of the modified silica Nanofiller on the Mechanical Properties of Unsaturated Polyester Resins Based on Recycled Polyethylene Terephthalate

et al. 2015

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“…Further, drawbacks of other conventional chemical recycling methods (hydrolysis, methanolysis) like high temperature and high pressure conditions were aimed of being avoided by aminolysis and ammonolysis. After depolymerization, in general, the reaction products were applied as curing agents for epoxy resins, as components for polyurethane synthesis or as plasticizers [225][226][227][228].…”

Section: Aminolysis/ammonolysismentioning

confidence: 99%

“…The chemicals such as alkyl amines or liquid ammonia are used in excess for PET de-polymerization (Table 4). Aminolysis and ammonolysis mainly yielded the corresponding monomeric amides of terephthalic acid [223,[226][227][228][229][230][231][232][233][234]. The de-polymerization agent, which was mainly applied, was ethanol amine (EA, Table 4).…”

Section: Aminolysis/ammonolysismentioning

confidence: 99%

“…Further, but less used chemicals for aminolysis or ammonolysis of PET are methyl amine (MA), liquor ammonia (NH 3 ) and ethylene diamine (EDA). As in case of EA, these chemicals lead to the formation of corresponding bi-functional monomers of terephthalic acid, which could be applied as curing agents for epoxy resins [227,228,233]. Hoang and Dang used excess EDA to depolymerize PET to low molecular weight oligomers (250-820 g·mol -1 , Table 4 ).…”

Section: Aminolysis/ammonolysismentioning

confidence: 99%

“…More et al [224] compared zinc acetate and sodium acetate for PET-aminolysis and found (as in case of glycolysis) zinc acetate to be more efficient for aminolysis reaction. Mittal et al [228] compared aminolysis and ammonolysis using cetyl am- monium bromide as catalyst. Generally, both reaction types yielded less monomeric reaction product without catalyst.…”

Section: Aminolysis/ammonolysismentioning

confidence: 99%

See 2 more Smart Citations

Recycling of poly(ethylene terephthalate) – A review focusing on chemical methods

Geyer¹,

Lorenz²,

Kandelbauer³

2016

Express Polym. Lett.

206

120

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Abstract.Recycling of poly(ethylene terephthalate) (PET) is of crucial importance, since worldwide amounts of PETwaste increase rapidly due to its widespread applications. Hence, several methods have been developed, like energetic, material, thermo-mechanical and chemical recycling of PET. Most frequently, PET-waste is incinerated for energy recovery, used as additive in concrete composites or glycolysed to yield mixtures of monomers and undefined oligomers. While energetic and thermo-mechanical recycling entail downcycling of the material, chemical recycling requires considerable amounts of chemicals and demanding processing steps entailing toxic and ecological issues. This review provides a thorough survey of PET-recycling including energetic, material, thermo-mechanical and chemical methods. It focuses on chemical methods describing important reaction parameters and yields of obtained reaction products. While most methods yield monomers, only a few yield undefined low molecular weight oligomers for impaired applications (dispersants or plasticizers). Further, the present work presents an alternative chemical recycling method of PET in comparison to existing chemical methods.

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Recycling Polyesters by Chemical Depolymerization

Cornell

2004

Modern Polyesters: Chemistry and Technology of Polyesters and Copolyesters

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In the presented paper, two basic strategies that can be used in the processes of chemical recycling of polyester material were described. The first of them involves increasing the molar mass of recycled materials in the solid-state polycondensation (SSP) process and/or joining their chains with various types of substances easily reacting with the end groups of polyesters (so-called extending agents). The essence of the second strategy is the degradation of the material under the influence of various protogenic agents (such as water, alcohols, glycols and amines) to obtain low-molecular products or oligomers that can be used as raw materials in the synthesis of many classes of polymers. The methods that are already used in PET [poly(ethylene terephthalate)] recycling and the possibility of their extension to other types of polyesters are both shown.

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Scanning electron microscopic study of hazardous waste flakes of polyethylene terephthalate (PET) by aminolysis and ammonolysis

Cited by 84 publications

References 15 publications

Effect of the modified silica Nanofiller on the Mechanical Properties of Unsaturated Polyester Resins Based on Recycled Polyethylene Terephthalate

Effect of the modified silica Nanofiller on the Mechanical Properties of Unsaturated Polyester Resins Based on Recycled Polyethylene Terephthalate

Recycling of poly(ethylene terephthalate) – A review focusing on chemical methods

Recycling Polyesters by Chemical Depolymerization

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