Stereocomplexation of low molecular weight poly(L-lactic acid) and high molecular weight poly(D-lactic acid), radiation crosslinking PLLA/PDLA stereocomplexes and their characterization

Quynh, Tran Minh; Hoa, Hoang; Lan, Pham Ngoc

doi:10.1016/j.radphyschem.2012.10.002

Cited by 27 publications

(24 citation statements)

References 22 publications

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“…The main peaks of PLLA (and for PDLA) appears at 2 θ values of 16.5° and 18.8°, which match measurements for the α form of PLLA crystallites in a pseudo‐orthorhombic unit cell . The most intense peaks of St‐PLA appear at 11.9°, 20.7°, and 23.9°, which are assigned to the stereocomplex crystallites in a triclinic unit cell . Peaks of St‐PLA/NR blends (for all NR content) appear in the same places as in the St‐PLA sample.…”

Section: Resultssupporting

confidence: 63%

“…The absorption at 1,036 cm −1 is assigned to –NH of protein in NR and 839 cm −1 is bending vibrations of C‐H bond in the double bond of NR molecular chain . The St‐PLA sample had a strong peak corresponding to carbonyl (CO) stretching at 1,744 cm −1 . After St‐PLA and NR were blended to form St‐PLA/NR, the characteristic peaks of NR and St‐PLA are also present in the composite spectra.…”

Section: Resultsmentioning

confidence: 99%

“…) were calculated :

χ_{h c} true(% true) = \frac{I_{h c}}{I_{h c} + I_{s t} + I_{a m o r}} \times 100

χ_{s t} true(% true) = \frac{I_{s t}}{I_{h c} + I_{s t} + I_{a m o r}} \times 100

where I hc is the integrated scattering intensity of the reflections of homocrystals, i.e.16.5° and 18.8°

,

I st is the sum of the areas under the scattering intensity peaks for the stereocomplex crystallites reflections, i.e. 11.9°, 20.7°, and 23.9° , I amor is the integrated intensity of the amorphous halo.…”

Section: Methodsmentioning

confidence: 99%

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Melt compounding and characterization of poly(lactide) stereocomplex/natural rubber composites

Pholharn

Srithep

Morris

2017

Polymer Engineering & Sci

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Poly(lactide) (PLA) is an interesting biodegradable polymer but has limited application because of its brittleness and low thermal stability. We found that both drawbacks of PLA were solved by forming stereocomplexes augmented with natural rubber (NR). Equal amounts of poly(l‐lactide) (PLLA) and poly(d‐lactide) (PDLA) stereoisomers were blended to form a stereocomplex (St‐PLA). Varying amounts of NR (5–30% by weight) were added simultaneously to equal amounts of the stereo isomers by melt blending. FTIR and XRD spectra demonstrated that, despite the added NR, the stereocomplex structures were still generated and complete. Stereocomplex crystallinity decreased with increasing NR content, verified by DSC and XRD, as well as polarizing optical micrographs which showed fewer spherulites at higher NR content. Measured glass transition temperatures (Tg) of St‐PLA/NR blends were significantly lower than for neat St‐PLA, exhibiting shifts to as low as 46°C at 30%wt NR content, because of rubber dispersed in St‐PLA segments expanding the free volume and enhancing chain mobility. Thermal stability of the blends, estimated by TGA, showed desired results, for example, at the 50% weight loss point, the temperature of all St‐PLA/NR blends moved to higher temperatures than neat St‐PLA. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers

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Section: Resultssupporting

confidence: 63%

Section: Resultsmentioning

confidence: 99%

“…) were calculated :

χ_{h c} true(% true) = \frac{I_{h c}}{I_{h c} + I_{s t} + I_{a m o r}} \times 100

χ_{s t} true(% true) = \frac{I_{s t}}{I_{h c} + I_{s t} + I_{a m o r}} \times 100

where I hc is the integrated scattering intensity of the reflections of homocrystals, i.e.16.5° and 18.8°

,

Section: Methodsmentioning

confidence: 99%

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Melt compounding and characterization of poly(lactide) stereocomplex/natural rubber composites

Pholharn

Srithep

Morris

2017

Polymer Engineering & Sci

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“…The characteristic absorption peaks of LG‐g‐PLA at 2998 and 2948 cm −1 are attributed to the characteristic absorption of methyl and methylene in PLA, respectively. In addition, a new characteristic peak at 1748 cm −1 was found in the infrared spectrum of LG‐g‐PLA, which is attributed to the asymmetric stretching of CO in the branched PLA after ring‐opening polymerization 40 . The aforementioned results verify the successful synthesis of LG‐g‐PLA.…”

Section: Resultssupporting

confidence: 52%

Increased expansion ratio, cell density, and compression strength of microcellular poly(lactic acid) foams via lignin graft poly(lactic acid) as a biobased nucleating agent

Zong

Chai

et al. 2020

Polymers for Advanced Techs

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Green and renewable foaming poly(lactic acid) (PLA) represents one of the promising developments in PLA materials. This study is the first to use the lignin graft PLA copolymer (LG‐g‐PLA) to improve the foamability of PLA as a biobased nucleating agent. This agent was synthesized via ring‐opening polymerization of lignin and lactide. The effects of LG‐g‐PLA on cell nucleation induced by the crystallization, rheological behavior, and foamability of PLA were evaluated. Results indicated that LG‐g‐PLA can improve the crystallization rate and crystallinity of PLA, and play a significant nucleation role in the microcellular foam processing of PLA. LG‐g‐PLA improved the foam morphology of PLA, obtaining a reduced and uniform cell size as well as increased expansion ratio and cell density. With the addition of 3 wt% LG‐g‐PLA content, the PLA/LG‐g‐PLA foams increased the compressive strength 1.6 times than that of neat PLA foams. The improved foaming properties of PLA via a biobased nucleating agent show potential for the production and application of green biodegradable foams.

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“…Gamma radiation has been proven to be an effective tool to introduce the crosslinking networks in polymer matrix for a long time. Even several degradation-type polymers can crosslink by gamma irradiation in the presence of crosslinking agents such as trimethylallyl isocyanurate (TMAIC), triallyl isocyanurate (TAIC), epichlorohydrin (ECH) [15,16].…”

Section: Introductionmentioning

confidence: 99%

Gelation of Dna and Bovine Serum Albumin (Dna-Bsa Gel) by Gamma Irradiation as Bio-Absorbent for Acridine Orange

Saito¹,

Quynh²,

Furusawa³

et al. 2016

RAD Conference Proceedings

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Abstract. Together with their advantages, the availability of synthetic organic chemicals also caused many adverse effects to the environment due to the fact that they do not seem to be completely bio-degraded in nature. The residues of these synthetic organic compounds, such as polychlorinated biphenyl (PCBs), acridine orange (AO) and other aromatics, as well as their degraded intermediates, may become carcinogens or mutagens, which severely affect human health. In the cell, these organic compounds can intercalate into the major grooves and interstices between the base pair of DNA double helix, resulting in several diseases and cancers. In other words, DNA can be utilized as the most efficient bio-adsorbent of such toxic agents. For this purpose, DNA must be in water-insoluble state. Recently, radiation has been proven to be one of the effective methods of introducing the crosslinking network in the polymer matrix. Though DNA is easily broken by radiation, it can crosslink in the presence of suitable crosslinkers, or be immobilized onto the crosslinking gels. In this study, we have successfully prepared DNA/BSA complex gels from aqueous mixtures of DNA with BSA by gamma irradiation. Their gelation behaviors were characterized for utilization as adsorbents for AO. The results indicated that the adsorption was a time-dependent process and the adsorption capacity of AO increased with DNA amount in the DNA/BSA gels.

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Stereocomplexation of low molecular weight poly(L-lactic acid) and high molecular weight poly(D-lactic acid), radiation crosslinking PLLA/PDLA stereocomplexes and their characterization

Cited by 27 publications

References 22 publications

Melt compounding and characterization of poly(lactide) stereocomplex/natural rubber composites

Melt compounding and characterization of poly(lactide) stereocomplex/natural rubber composites

Increased expansion ratio, cell density, and compression strength of microcellular poly(lactic acid) foams via lignin graft poly(lactic acid) as a biobased nucleating agent

Gelation of Dna and Bovine Serum Albumin (Dna-Bsa Gel) by Gamma Irradiation as Bio-Absorbent for Acridine Orange

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