Present and Future of PLA Polymers

Vert, Michel; Schwarch, G.; Coudane, Jean

doi:10.1080/10601329508010289

Cited by 352 publications

(233 citation statements)

References 37 publications

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“…Indeed, molecular chains packed in the crystalline phase absorb a lower amount of water with respect to the less dense amorphous phase. This fact explains why the amorphous PLA 50 GA 50 degrades faster than the semicrystalline PGA, even if the latter is more hydrophilic [56,57]. Other factors affecting degradation kinetics are polymer molecular weight and shape of the device.…”

Section: Biomaterialsmentioning

confidence: 97%

“…It is pointed out, however, that hydrolysis occurs depending mainly on material hydrophilicity and, for this reason, not all polyesters can be considered as hydrolizable materials (the aromatic polyester polyethylenterephtalate, for example, is highly stable in aqueous environment). It is worth noting that one potential concern arises from the local pH changes that can occurs during degradation as a consequence of acid nature of degradation products [50].…”

Section: Biomaterialsmentioning

confidence: 99%

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Porous Polymeric Bioresorbable Scaffolds for Tissue Engineering

Gualandi

2011

Springer Theses

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and some lactide copolymers) and of non-commercial polyesters (i.e. poly-ω-pentadecalactone and some of its copolymers) were explored and discussed.Two techniques were employed to fabricate scaffolds: supercritical carbon dioxide (scCO 2 ) foaming and electrospinning (ES). The former is a powerful technology that enables to produce 3D microporous foams by avoiding the use of solvents that can be toxic to mammalian cells. The scCO 2 process, which is II commonly applied to amorphous polymers, was successfully modified to foam a highly crystalline poly(ω-pentadecalactone-co-ε-caprolactone) copolymer and the effect of process parameters on scaffold morphology and thermo-mechanical properties was investigated.In the course of the present research activity, sub-micrometric fibrous nonwoven meshes were produced using ES technology. Electrospun materials are considered highly promising scaffolds because they resemble the 3D organization of native extra cellular matrix. A careful control of process parameters allowed to fabricate defect-free fibres with diameters ranging from hundreds of nanometers to several microns, having either smooth or porous surface. Moreover, versatility of ES technology enabled to produce electrospun scaffolds from different polyesters as well as "composite" non-woven meshes by concomitantly electrospinning different fibres in terms of both fibre morphology and polymer material. The 3D-architecture of the electrospun scaffolds fabricated in this research was controlled in terms of mutual fibre orientation by properly modifying the instrumental apparatus. This aspect is particularly interesting since the micro/nano-architecture of the scaffold is known to affect cell behaviour.Since last generation scaffolds are expected to induce specific cell response, the present research activity also explored the possibility to produce electrospun scaffolds bioactive towards cells. Bio-functionalized substrates were obtained by loading polymer fibres with growth factors (i.e. biomolecules that elicit specific cell behaviour) and it was demonstrated that, despite the high voltages applied during electrospinning, the growth factor retains its biological activity once

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Section: Biomaterialsmentioning

confidence: 97%

Section: Biomaterialsmentioning

confidence: 99%

Porous Polymeric Bioresorbable Scaffolds for Tissue Engineering

Gualandi

2011

Springer Theses

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“…In addition, strong association between linear aliphatic PLA's chain, and the hydroxypropyl grafting from the derivatives during blending might be also considered. On the other hand, low interaction between neat polyflavonoids and PLA-chains can be explained in terms of the high differences in polarity of the two biopolymers [10,17]. However, molecular association between PLA and polyflavonoids in the molten-state has not been documented before.…”

Section: Evaluation Of Processability By Torquementioning

confidence: 98%

“…However, degradation of PLA in polyflavonoidbased binary blends was the highest regardless the polyflavonoid-type. The degradation mechanisms of PLA-based materials have been well-described [1,17,18]. In fact, several components on blends have been recognized as degradation promoters of PLAdegradation [22][23][24][25][26].…”

Section: Molecular Weight Distributionmentioning

confidence: 99%

Bark polyflavonoids from Pinus radiata as functional building-blocks for polylactic acid (PLA)-based green composites

García¹,

Carrasco²,

Salazar³

et al. 2016

Express Polym. Lett.

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The most important polymers in bioplastic engineering are aliphatic polyesters such as polylactic acid (PLA) [1]. Blending of PLA with other polymers such as polypropylene, natural rubbers, polyglycols (PEG), polyvinyl acetate, polyolefins, polymethyl methacrylate, and polycarbonate is an useful route towards modifying properties [2]. In addition, oligomers/polymers from lignocellulosic resources have been used as additives in order to reduce cost [3][4][5]. In fact, many advantages are recognized in binary and ternary blends regarding well dispersion into the PLA-matrix, and the nucleating effect of certain biopolymers which induced dramatic changes on mechanical properties [6]. Moreover, lignin and condensed tannin (polyflavonoids) have been successfully blended with PLA [7]. However, there are few reports which describe the effect of polyflavonoids on the PLA physicochemical properties. Polyphenols properties such as an- Abstract. Polylactic acid (PLA) was melt-blended with Pinus radiata unmodified and modified (hydroxypropyled) bark polyflavonoids in order to use such polyphenolic building-blocks as functional additives for envisaged applications. Rheological, morphological, molecular, thermal, and flexural properties were studied. Polyflavonoids improved blend processability in terms of short-time mixing. Furthermore, hydroxypropylated polyflavonoids improve miscibility in binary and ternary blends. Blend-composition affects crystallization-, melting-, and glass transition-temperature of PLA, as well as thermal resistance, and flexural properties of the blends. Polyflavonoids induced PLA-crystallization, and polymer-chain decomposition. Modified and unmodified bark polyflavonoids from radiata pine can be used successfully in PLA-based green composites beyond the food-packaging applications. The high compatibility between PLA and hydroxypropyled polyflavonoids highlights the potential of such phenolic derivatives for PLA-based material design.

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“…Copolymerization provides materials with a wider range of properties. PLA copolymers present all the classical structures, namely random, diblock or multiblock, star, etc., with all the consequent variations in properties one can predict from such differences (Vert, 1995).…”

Section: Copolymerization Of Poly (Lactic Acid)mentioning

confidence: 99%

Synthesis and Characterization of PLA-Based Aliphatic-Aromatic Copolyesters: Effect of Diols

Namkajorn

Petchsuk

Opaprakasit

et al. 2008

AMR

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AcknowledgementI wish to express my deepest and sincere gratitude to my supervisor, Asst. Prof. Dr. Pakorn Opaprakasit for his supervision, valuable instructions, excellent suggestions, kindness and assistance on the preparation of this thesis. This accomplishment would not be possible without his help.Moreover, I feel very thankful and grateful to Dr. Atitsa Petchsuk, Dr. Mantana Opaprakasit for their kindness and valuable discussion and comments on this thesis.My appreciation is also extended to the staff of the School of Bio-Chemical Engineering and Technology and the department of Common and Graduate Studies, Sirindhorn International Institute of Technology (SIIT), Thammasat University.Unforgettably, this work was made possible by a financial support from the SIIT-NSTDA scholarship and partial support from the teaching assistant program.I would like to thank all of my colleagues for great cooperation and the best wonderful relationship. Finally, thank you my lovely family for their love and encouragement.Montree Namkajorn ii Abstract PLA-based aliphatic aromatic copolyesters have been synthesized and characterized in order to incorporate the degradability of PLA and good mechanical property of aromatic species. Synthesis of the copolymer was conducted by polycondensation of lactic acid with dimethyl terephthalate (DMT) and diols using Stannous(II)octoate as a catalyst. Four types of diols with different methylene length were employed, i.e., ethylene glycol (EG), propylene glycol (PG), 1, 4-butanediol (BD), 1,3-propanediol (PD). Effects of diols and comonomer ratio on the polycondensation and the molecular weight of resulting copolymers were investigated. Diacids and diol ratios of L-lactic acid (LLA), dimethyl terephthalate (DMT) and diol of 1/1/2, 1/2/4, and 2/1/2 were employed, respectively. Characterization of chemical property, molecular weight, thermal property and degradability of the resulting copolymers were conducted by FTIR, UV, NMR, TGA, and DSC experiments.

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Present and Future of PLA Polymers

Cited by 352 publications

References 37 publications

Porous Polymeric Bioresorbable Scaffolds for Tissue Engineering

Porous Polymeric Bioresorbable Scaffolds for Tissue Engineering

Bark polyflavonoids from Pinus radiata as functional building-blocks for polylactic acid (PLA)-based green composites

Synthesis and Characterization of PLA-Based Aliphatic-Aromatic Copolyesters: Effect of Diols

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