Effect of gamma irradiation on the physicochemical properties of sodium alginate solution and internally crosslinked film made thereof

Chang, Kian Aun; Chew, Lye Yee; Law, Kung Pui; Ng, Jeck Fei; Wong, Chee Sien; Wong, Ching-Lee; Hussein, Sobri

doi:10.1016/j.radphyschem.2022.109963

Cited by 8 publications

(4 citation statements)

References 32 publications

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“…The degradation of EPR/ Ascophyllum nodosum powder samples in water and physiological serum ( Figure 6 ) is subjected to the effects of interference with water. The water dipoles act as hydrolysis agent [ 89 ] as well as attack agent in thermal [ 90 ] and radiation [ 91 ] environments. The degradation rates present greater values for the modified polymer, while the neat EPR resist for longer periods in aqueous solutions.…”

Section: Resultsmentioning

confidence: 99%

Stabilization Activity of Kelp Extract in Ethylene–Propylene Rubber as Safe Packaging Material

Zaharescu¹

2023

Polymers

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This paper presents the stabilization effects of the solid extract of kelp (Ascophyllum nodosum) on an engineering elastomer, ethylene–propylene copolymer (EPR), which may be used as packaging material. Progressive increase in additive loadings (0.5, 1, and 2 phr) increases the oxidation induction time for thermally aged rubber at 190 °C from 10 min to 30 min for pristine material and modified polymer by adding 2 phr protection powder. When the studied polymer is γ-irradiated at 50 and 100 kGy, the onset oxidation temperatures increase as a result of blocking the oxidation reactivity of free radicals. The stabilization effect occurs through the activity of alginic acid, which is one of the main active components associated with alginates. The accelerated degradation caused by γ-exposure advances more slowly when the kelp extract is present. The OOT value for the oxidation of EPR samples increases from 130 °C to 165 °C after the γ-irradiation of pristine and modified (2 phr of kelp powder) EPR, respectively. The altered oxidation state of EPR samples by the action of γ-rays in saline serum is faster in neat polymer than in stabilized material. When the probes are placed in physiological serum and irradiated at 25 kGy, the OOT value for neat EPR (145 °C) is much lower than the homologous value for the polymer samples protected by kelp extract (153 °C for the concentration of 0.5 phr, 166 °C for the concentration of 1 phr, and 185 °C for the concentration of 2 phr).

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Section: Resultsmentioning

confidence: 99%

Stabilization Activity of Kelp Extract in Ethylene–Propylene Rubber as Safe Packaging Material

Zaharescu¹

2023

Polymers

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“…Even though the cross-link density decreases with increasing PP concentration, at the 20 kGy irradiation dose, the mesh size also increases, possibly due to the degradative effects that compete with the cross-linking ones as a result of continuously generated free radicals [ 41 ]. Upon irradiation, a large number of free radicals and active sites [ 45 ] are formed throughout the system due to the decomposition of PEO [ 26 , 46 , 47 ], AA [ 48 , 49 ], and SA [ 48 , 49 , 50 , 51 ], mainly due to the water radiolysis process. These highly active free radicals created by high-energy irradiation initiate and drive the cross-linking and grafting reactions [ 45 ].…”

Section: Resultsmentioning

confidence: 99%

Poly(Acrylic Acid)-Sodium Alginate Superabsorbent Hydrogels Synthesized by Electron Beam Irradiation Part I: Impact of Initiator Concentration and Irradiation Dose on Structure, Network Parameters and Swelling Properties

et al. 2023

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In the present paper, hydrogels based on acrylic acid (20%), sodium alginate (0.5%) and poly(ethylene oxide) (0.1%) were obtained by electron beam irradiation at room temperature with doses between 5 and 20 kGy, using potassium persulfate in concentrations up to 0.3% as a reaction initiator. The influence of initiator concentration and irradiation dose on hydrogel network parameters, swelling and deswelling behavior, gelation and degradation points, structure and morphology were investigated. Cross-link density increased with the irradiation dose and initiator addition, except at 20 kGy. The gel fraction was over 87.0% in all cases. Swelling experiments in distilled water showed swelling degrees of 40,000% at an irradiation dose of 5 kGy when a concentration of 0.1% initiator was added. A relationship between the swelling degree and irradiation dose, cross-linking degree (that increases from 0.044 × 102 to 0.995 × 102 mol/cm3) and mesh size (that decreases from about 220 nm to 26 nm) was observed. The addition of only 0.1% of PP led to the obtaining of hydrogels with a swelling degree of 42,954% (about 430 g/g) at an irradiation dose of 5 kGy and of 7206% (about 62 g/g) at 20 kGy, which are higher percentages than those obtained in the same irradiation conditions but without PP.

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“…Since standard sterilisation techniques such as autoclaving (Lorson et al (2020)) and gamma irradiation (Chang et al (2022)), alter the physicochemical properties of the polymer, UV sterilisation of sodium alginate powder was investigated. While Lorson et al (2020) advised against the use of UV irradiation due to an ineffective sterilisation outcome, Yu et al (2017) showed good results for two UV cycles of 25 min.…”

Section: Discussionmentioning

confidence: 99%

Establishing a co-culture aggregate of N-cycle bacteria to elucidate flocculation in biological wastewater treatment

Parret,

Simoens,

Horemans

et al. 2024

Preprint

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Biological flocculation is a complex phenomenon that is often treated as a black box. As a result, flocculation problems are usually remediated without knowledge of the exact causes. We show that it is feasible to exploit a model (N-cycle) consortium with reduced complexity to fundamentally study bioflocculation. Strong nitrifier microcolonies were formed during oxic/anoxic cycles in sequencing batch reactors, using alginate entrapment as a cell retention system. After release of these aggregates into suspension, macroclusters with flocs of the denitrifier were observed. These results suggest that a living model of a full-scale activated sludge floc can be built through the use of this bottom-up approach. By eliminating shifts in the microbial community, the applied experimental conditions have a more direct effect on the observations.

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Effect of gamma irradiation on the physicochemical properties of sodium alginate solution and internally crosslinked film made thereof

Cited by 8 publications

References 32 publications

Stabilization Activity of Kelp Extract in Ethylene–Propylene Rubber as Safe Packaging Material

Stabilization Activity of Kelp Extract in Ethylene–Propylene Rubber as Safe Packaging Material

Poly(Acrylic Acid)-Sodium Alginate Superabsorbent Hydrogels Synthesized by Electron Beam Irradiation Part I: Impact of Initiator Concentration and Irradiation Dose on Structure, Network Parameters and Swelling Properties

Establishing a co-culture aggregate of N-cycle bacteria to elucidate flocculation in biological wastewater treatment

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