Oligomeric chain extenders for economic reprocessing and recycling of condensation plastics

Villalobos, Marco; Awojulu, Abiodun A.; Greeley, T.; Turco, Gregory P.; Deeter, Gary A.

doi:10.1016/j.energy.2006.03.026

Cited by 177 publications

(212 citation statements)

References 6 publications

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“…The hydroxyl-terminal groups of PLA are less reactive with the epoxy groups and should remain substantially unreacted. This should avoid crosslinking and gel formation [41,42]. The PLA and CE were dried at 558C for a minimum of 8 h prior to use.…”

Section: Methodsmentioning

confidence: 99%

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Rheology and extrusion foaming of chain‐branched poly(lactic acid)

Mihai

Huneault

Favis

2009

Polymer Engineering & Sci

227

204

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Rheology and extrusion foaming of chain-branched poly(lactic acid)Mihai, Mihaela; Huneault, Michel A.; Favis, Basil D.Contact us / Contactez nous: nparc.cisti@nrc-cnrc.gc.ca. In this study, the effect of macromolecular chainbranching on poly(lactic acid) (PLA) rheology, crystallization, and extrusion foaming was investigated. Two PLA grades, an amorphous and a semi-crystalline one, were branched using a multifunctional styrene-acrylicepoxy copolymer. The branching of PLA and its foaming were achieved in one-step extrusion process. Carbon dioxide (CO 2 ), in concentration up to 9%, was used as expansion agent to obtain foams from the two PLA branched using chain-extender contents up to 2%. The foams were investigated with respect to their shear and elongational behavior, crystallinity, morphology, and density. The addition of the chain-extender led to an increase in complex viscosity, elasticity, elongational viscosity, and in the manifestation of the strain-hardening phenomena. Low-density foams were obtained at 5-9% CO 2 for semi-crystalline PLA and only at 9% CO 2 in the case of the amorphous PLA. Differences in foaming behavior were attributed to crystallites formation during the foaming process. The rheological and structural changes associated with PLA chain-extension lowered the achieved crystallinity but slightly improved the foamability at low CO 2 content. POLYM. ENG. SCI.,

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Section: Methodsmentioning

confidence: 99%

“…For example, ethylene-methyl acrylate-glycidyl methacrylate copolymers have successfully been used for the branching of PET [40]. Recently, a multifunctional styrene-acrylic-epoxy random oligomer, with a molecular weight around 3000 g/mol, has been proposed as chain-extender without the aforementioned limitations [41,42].…”

Section: Introductionmentioning

confidence: 99%

Rheology and extrusion foaming of chain‐branched poly(lactic acid)

Mihai

Huneault

Favis

2009

Polymer Engineering & Sci

227

204

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“…Despite all the advantages of PLA, there are nevertheless some drawbacks, especially a low molecular weight, which affects the polymer melt viscosity, melt elasticity, mechanical and thermal properties [10,11]. One of the possible methods to increase the molecular weight is the use of chain extenders (CE) that cause a change from the linear to long chain branched structures [12]. Chain extension relays on reaction of functional groups of amines, anhydrides, carboxylic acids and isocyanates with the carboxyl or hydroxyl end groups of PLA chains.…”

Section: Introductionmentioning

confidence: 99%

Foaming of Polylactide in the Presence of Chain Extender

Ludwiczak

Kozłowski

2014

J Polym Environ

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An experimental study on the influence of chain extender (CE) on the properties and foamability of two grades of polylactide (PLA) has been carried out. The influence of CE on the polymer crystallinity and viscoelastic properties that are critical during the foaming process was investigated. After addition of CE an increase in the viscosity and the cold crystallization temperature of PLA was observed. Selection of PLA grade has been correlated with a structure of the polymer. The cellular structure of PLA was obtained during extrusion process using the chemical blowing agent. The addition of 1.0 and 1.5 % CE caused fine cellular structure and low density (0.7 g/dm 3 ) of foamed PLA.

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“…The chain extension reaction is rendered schematically in figure 6 (Villalobos et al, 2006) The most suggestive presentation of the way in which the chain extension reaction can develop depending on the reaction conditions (i.e. concentration of the extender) and how the same material can yield both chain extension and reticulation was accomplished by (Villalobos et al, 2006;) ( fig.7).…”

Section: Methods For Postc-pet Up-gradation By Chain Extensionmentioning

confidence: 99%