In-situ visualization of PLA crystallization and crystal effects on foaming in extrusion

Tabatabaei, Alireza; Park, Chul

doi:10.1016/j.eurpolymj.2017.09.026

Cited by 40 publications

(21 citation statements)

References 74 publications

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“…The crystallization behavior of PLA in a foam extrusion process was investigated by Tabatabaei and Park [ 62 ] with a special in situ visualization technique located in the die. It was shown that the crystallization kinetics were promoted by a strain-induced crystallization within the die.…”

Section: Processesmentioning

confidence: 99%

Chemical Modification and Foam Processing of Polylactide (PLA)

et al. 2019

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Polylactide (PLA) is known as one of the most promising biopolymers as it is derived from renewable feedstock and can be biodegraded. During the last two decades, it moved more and more into the focus of scientific research and industrial use. It is even considered as a suitable replacement for standard petroleum-based polymers, such as polystyrene (PS), which can be found in a wide range of applications—amongst others in foams for packaging and insulation applications—but cause strong environmental issues. PLA has comparable mechanical properties to PS. However, the lack of melt strength is often referred to as a drawback for most foaming processes. One way to overcome this issue is the incorporation of chemical modifiers which can induce chain extension, branching, or cross-linking. As such, a wide variety of substances were studied in the literature. This work should give an overview of the most commonly used chemical modifiers and their effects on rheological, thermal, and foaming behavior. Therefore, this review article summarizes the research conducted on neat and chemically modified PLA foamed with the conventional foaming methods (i.e., batch foaming, foam extrusion, foam injection molding, and bead foaming).

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Section: Processesmentioning

confidence: 99%

Chemical Modification and Foam Processing of Polylactide (PLA)

et al. 2019

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“…The polarized optical micrographs in Figure clearly confirmed the formation of spherulites crystals scattering in PLLA. Spherulites crystals of PLLA were barely generated with increasing cooling temperature due to slow crystallization behavior of PLA . Adding PDLA in PLLA increased spherulites crystals with increasing PDLA content.…”

Section: Resultsmentioning

confidence: 99%

Effect of poly(D‐lactic acid) and cooling temperature on heat resistance and antibacterial performance of stereocomplex poly(L‐lactic acid)

Boonluksiri

Prapagdee

Sombatsompop

2020

J of Applied Polymer Sci

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Stereocomplex nucleated polylactic acid was prepared by the addition of poly(D-lactic acid) (PDLA) in poly(L-lactic acid) (PLLA) under various cooling temperatures by monitoring the mechanical properties and heat resistance. Antibacterial performance against the growth of Escherichia coli on PLLA/PDLA doped with various contents of 2-hydroxypropyl-3-piperazinyl-quinoline carboxylic acid methacrylate (HPQM) was also evaluated. The results suggested that a small addition of PDLA generated stereocomplex crystals while increasing cooling temperature resulted in homo crystals formation in PLLA. The incorporation of PDLA with high cooling temperature increased the heat deflection temperature, impact resistance, and tensile modulus, but decreased the antibacterial performance against E. coli. The addition of PDLA at 2.0 wt% in PLLA at cooling temperature at 80 C showed a synergistic effect to obtain an exceptionally high heat deflection temperature up to 164 C. HPQM was, for the first time, introduced as antibacterial agent in PLLA with an optimum dosage of 1750 ppm.

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“…It should be noted that both MPET-1 and FPET have good melt strength to support extrusion foaming, but their crystallization rates are significantly different. Tabatabaei et al [52][53][54] investigated polymer strain-induced crystallization under the influence of scCO 2 in extrusion adopting mold visualization apparatus. It was observed that polymer crystallites were quickly formed inside the die at a temperature even above the melting temperature (T m ).…”

Section: Foaming Behavior Using Co 2 As Blowing Agentmentioning

confidence: 99%

Good extrusion foaming performance of long‐chain branched PET induced by its enhanced crystallization property

Yao

Guo

Liu

et al. 2020

J of Applied Polymer Sci

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Poly(ethylene terephthalate) (PET) was modified by regulating different contents of branching agent epoxy‐based multifunctional oligomer and chain extender pyromellitic dianhydride in reactive extrusion process. The modified PET with better long‐chain branched (LCB) structure boosted its rheological properties, and its enhancement of melt viscoelasticity resulted in excellent foamability in molten‐state foaming process using supercritical CO2 as blowing agent. More importantly, the branched structures acted as crystal sites to accelerate the crystallization kinetic of LCB PET whether under atmospheric pressure or high‐pressure CO2. The shear and elongation flow inside die further quickly induced the crystallization of LCB PET. The rapidly generated fine crystals could both introduce heterogeneous cell nucleation and suppress CO2 escape, so the cell morphology of LCB PET in continuous extrusion foaming process exhibited a three‐fold increase in cell density and smaller uniform cell size with respect to those of other foam‐grade PET with long‐chain structure.

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In-situ visualization of PLA crystallization and crystal effects on foaming in extrusion

Cited by 40 publications

References 74 publications

Chemical Modification and Foam Processing of Polylactide (PLA)

Chemical Modification and Foam Processing of Polylactide (PLA)

Effect of poly(D‐lactic acid) and cooling temperature on heat resistance and antibacterial performance of stereocomplex poly(L‐lactic acid)

Good extrusion foaming performance of long‐chain branched PET induced by its enhanced crystallization property

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