Effect of electron beam irradiation on the silk fibroin fiber/poly(ε‐caprolactone) composite

Li, Wei; Qiao, Xiuying; Sun, Kang; Chen, Xiao

doi:10.1002/app.29869

Cited by 16 publications

(12 citation statements)

References 31 publications

(50 reference statements)

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“…In all cases, strain at break decreased with the increase in dose [6,7,15,17] as found in this work except for one case where a slight increase in strain at break is found for a PCL of unknown molecular weight after irradiation with gamma rays at a 30.8 kGy dose [3]. For the stress at break, however, an increase in tensile stress was found when PCL was irradiated with electron beam [15,17] or gamma rays [3,7] up to 160–200 kGy followed by a decrease at higher doses. This is not the case for the results in this work, where a continuous decrease in stress at break was found with the increase in dose either with electron beam or gamma rays, without significant differences in between both ionizing radiations.…”

Section: Resultsmentioning

confidence: 99%

Effect of Ionizing Radiation on the Chemical Structure and the Physical Properties of Polycaprolactones of Different Molecular Weight

et al. 2018

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Polymers used in the biomedical sector can be exposed to ionizing radiation (X-ray, gamma) in vivo as implants or ex vivo for sterilization purposes (gamma, electron beam). This ionizing radiation can, at certain levels, cause degradation of the polymer. Polycaprolactones (PCL) of different molecular weights were irradiated with electron beam and the changes in their chemical structure and physical properties with the dose were evaluated. Electron beam irradiation produced crosslinking and chain scission in the PCL chain without significant predominance of one mechanism over the other. Minimum dose for gelation decreased with the increase in PCL molecular weight whereas crosslinking efficiency was almost independent of PCL molecular weight. Carboxylic groups, hydroxyl groups and new saturated hydrocarbon species were detected by proton nuclear magnetic resonance (NMR). These species were consistent with a mechanism where chain scission could take place at any bond in the PCL chain with preference in the –COO–CH2– bond. Crosslinking decreased significantly the crystallization temperature of PCL. Tensile properties decreased continuously with the increase in dose. Irradiation with gamma rays produced a faster decay in mechanical properties than electron beam.

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Section: Resultsmentioning

confidence: 99%

Effect of Ionizing Radiation on the Chemical Structure and the Physical Properties of Polycaprolactones of Different Molecular Weight

et al. 2018

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“…It should be noted that electron-beam irradiation of silk broin produces the similar doublet EPR spectrum [26,27]. Evidently, both electrons from the beam and electrons ejected from the aromatic residues are captured by the same group, the carbon atom of the carbonyl group.…”

Section: Epr Spectra Of the Free Radicals Induced By Uv Irradiation Omentioning

confidence: 92%

Dynamics of Proteins by Thermal Decay of Free Radicals Induced by Ultraviolet Irradiation

Aslanov

Dashdemirova

Alekperov

et al. 2018

Journal of Spectroscopy

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The relationship between structure, dynamics, and function of biomolecules is a fundamental interest of biophysics. Protein dynamics drastically vary in temporal and spatial scales. The function of a particular protein determines the significance of a distinct type of dynamics. Here, we investigate the influence of hydration water on the dynamics of a protein called silk fibroin. Particular interest is to investigate the protein dynamics using thermal decay of the free radicals induced by ultraviolet irradiation. The full decay of the free radicals occurs at very wide temperature region (120 K–340 K). Three distinct regions with transition points of ∼135 K, 205 K, and 279 K are apparent in the thermal decay curves of hydrated fibroin samples. The first transition (∼135 K) that leads 2–6% increase of total spins was observed only in the decay curves of fibroin submerged in 40% and 50% glycerol. The second transition (∼205 K) was invariant for all samples, hydrated and dry fibroins. The third transition of 279 K common for all hydrated fibroin samples was shifted about 84 K to a higher temperature of 363 K in dry fibroin. The thermal transitions at 205 K and 279 K are weakly and strongly, respectively, coupled to water molecules. Nature of the free radicals participated in these transitions was identified. The significance of the findings for protein dynamics is discussed.

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“…Therefore, replacing hydrophilic -OH by hydrophobic groups is an effective way to improve the hydrophobic properties of bamboo. The methods for modifying bamboo hydrophobicity, while using existing technology, include bamboo fiber steam explosion [7,8] and electron beam irradiation. These physical methods can improve the mechanical interlocking forces of bamboo flour (BF) and polymer composites to a certain extent, but they cannot form a strong chemical bond between the fiber and resin matrix.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of Esterified Bamboo Flour by an In Situ Solid Phase Method

Geng

Pei

et al. 2018

Polymers

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Bamboo plastic composites have become a hot research topic and a key focus of research. However, many strong, polar, hydrophilic hydroxyl groups in bamboo flour (BF) results in poor interfacial compatibility between BF and hydrophobic polymers. Maleic anhydride-esterified (MAH-e-BF) and lactic acid-esterified bamboo flour (LA-e-BF) were prepared while using an in situ solid-phase esterification method with BF as the raw material and maleic anhydride or lactic acid as the esterifying agent. Fourier transform infrared spectroscopy results confirmed that BF esterification with maleic anhydride and lactic acid was successful, with the esterification degrees of MAH-e-BF and LA-e-BF at 21.04 ± 0.23% and 14.28 ± 0.17%, respectively. Esterified BF was characterized by scanning electron microscopy, contact angle testing, X-ray diffractometry, and thermogravimetric analysis. The results demonstrated that esterified BF surfaces were covered with graft polymer and the surface roughness and bonding degree of MAH-e-BF clearly larger than those of LA-e-BF. The hydrophobicity of esterified BF was significantly higher than BF and the hydrophobicity of MAH-e-BF was better than LA-e-BF. The crystalline structure of esterified BF showed some damage, while MAH-e-BF exhibited a greater decrease in crystallinity than LA-e-BF. Overall, the esterification reaction improved BF thermoplasticity, with the thermoplasticity of MAH-e-BF appearing to be better than LA-e-BF.

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Effect of electron beam irradiation on the silk fibroin fiber/poly(ε‐caprolactone) composite

Cited by 16 publications

References 31 publications

Effect of Ionizing Radiation on the Chemical Structure and the Physical Properties of Polycaprolactones of Different Molecular Weight

Effect of Ionizing Radiation on the Chemical Structure and the Physical Properties of Polycaprolactones of Different Molecular Weight

Dynamics of Proteins by Thermal Decay of Free Radicals Induced by Ultraviolet Irradiation

Preparation and Characterization of Esterified Bamboo Flour by an In Situ Solid Phase Method

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