Novel aspects of the degradation process of PLA based bulky samples under conditions of high partial pressure of water vapour

Kucharczyk, Pavel; Hnatkova, Eva; ZdenekDvorak,; Sedlařík, Vladimír

doi:10.1016/j.polymdegradstab.2012.10.016

Cited by 26 publications

(22 citation statements)

References 38 publications

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“…Table illustrates the effect of abiotic hydrolysis (at 0.1 mol L −1 , pH 7) on the thermal properties of the microcellular samples and contrasts them with those of the nonporous materials. The samples were initially highly amorphous, but after 12 weeks, a visible increase in crystallinity was detected in the microcellular samples only. This indicated production of a fresh degradation product, one possessing sufficient mobility to enable formation of a crystalline lattice during hydrolysis .…”

Section: Resultsmentioning

confidence: 96%

“…The samples were initially highly amorphous, but after 12 weeks, a visible increase in crystallinity was detected in the microcellular samples only. This indicated production of a fresh degradation product, one possessing sufficient mobility to enable formation of a crystalline lattice during hydrolysis . Notably, PLA/MSS5 showed the highest value for the degree of crystallinity, potentially attributable to the highly porous structure of the specimen.…”

Section: Resultsmentioning

confidence: 96%

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Microcellular antibacterial polylactide‐based systems prepared by additive extrusion with ALUM

Moghaddam

Stloukal

Kucharczyk

et al. 2019

Polymers for Advanced Techs

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This work investigates preparation by extrusion of microcellular antimicrobial polylactide (PLA) with an additive, the latter comprising 1% potassium aluminum sulfate dodecahydrate (ALUM), and 3% or 5% of a mixture of sodium hydrogen carbonate and sodium dihydrogen phosphate (1:1). Study was made as to the properties of the materials, their hydrolysis, release profiles, and antimicrobial properties in comparison with the pure polymer. Measuring the molecular weight of samples by gel permeation chromatography revealed that, during thermal processing, the molecular weight of the PLA prepared with additives mentiond above had reduced by approximately 43%. A mechanical test confirmed a decline in mechanical properties after processing as compared with the pure PLA. Release of the antimicrobial compound and the subsequent antimicrobial activity against Staphylococcus aureus and Escherichia coli was evaluated according to ISO 22196:2007. The release of ALUM from the microcellular specimens took place in two steps. During the first 10 days, the rate of release was extremely high in contrast with the remaining period.However, the release rate of the nonporous sample was seen to equal less than 1% in the first 10 days, a phenomenon probably arising through its less active surface.

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Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 96%

Microcellular antibacterial polylactide‐based systems prepared by additive extrusion with ALUM

Moghaddam

Stloukal

Kucharczyk

et al. 2019

Polymers for Advanced Techs

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“…Moreover, while in the case of polyolefins the side reactions can be partially avoided by tuning and optimizing the feed ratios and the experimental conditions, the MA free‐radical grafting reaction on PLA seems to be affected by uncontrolled collateral reactions that cause an extensive degradation independently of the experimental conditions. In addition, the back‐biting reaction and thermo‐hydrolysis, which is due to the presence of water traces, are also invoked to justify the extensive molecular weight decrement occurring with a substantial detriment of final mechanical properties …”

Section: Introductionmentioning

confidence: 99%

Towards a better control of the radical functionalization of poly(lactic acid)

Domenichelli

Coiai

Cicogna

et al. 2014

Polymer International

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“…The deposition system, schematically depicted in Figure 1 a, consisted of a stainless steel high vacuum chamber (volume 35 L), equipped with an electrically heated copper crucible loaded with PLA powder (prepared according to [ 35 ], molar mass M n = 8300 g/mol; M w = 19,000 g/mol, the chemical structure of which is presented in Figure 1 b). Above the crucible, a circular excitation electrode was placed at the distance of 4 cm, and quartz crystal microbalance sensor (QCM) was placed at a distance of 10 cm.…”

Section: Methodsmentioning

confidence: 99%

Structure of Plasma (re)Polymerized Polylactic Acid Films Fabricated by Plasma-Assisted Vapour Thermal Deposition

et al. 2021

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Plasma polymer films typically consist of very short fragments of the precursor molecules. That rather limits the applicability of most plasma polymerisation/plasma-enhanced chemical vapour deposition (PECVD) processes in cases where retention of longer molecular structures is desirable. Plasma-assisted vapour thermal deposition (PAVTD) circumvents this limitation by using a classical bulk polymer as a high molecular weight “precursor”. As a model polymer in this study, polylactic acid (PLA) has been used. The resulting PLA-like films were characterised mostly by X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR) spectroscopy. The molecular structure of the films was found to be tunable in a broad range: from the structures very similar to bulk PLA polymer to structures that are more typical for films prepared using PECVD. In all cases, PLA-like groups are at least partially preserved. A simplified model of the PAVTD process chemistry was proposed and found to describe well the observed composition of the films. The structure of the PLA-like films demonstrates the ability of plasma-assisted vapour thermal deposition to bridge the typical gap between the classical and plasma polymers.

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Novel aspects of the degradation process of PLA based bulky samples under conditions of high partial pressure of water vapour

Cited by 26 publications

References 38 publications

Microcellular antibacterial polylactide‐based systems prepared by additive extrusion with ALUM

Microcellular antibacterial polylactide‐based systems prepared by additive extrusion with ALUM

Towards a better control of the radical functionalization of poly(lactic acid)

Structure of Plasma (re)Polymerized Polylactic Acid Films Fabricated by Plasma-Assisted Vapour Thermal Deposition

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