The Effects of Accelerated Photooxidation on Molecular Weight and Thermal and Mechanical Properties of PHBV/Cloisite 30B Bionanocomposites

Iggui, Kahina; Kaci, Mustapha; Moigne, Nicolas Le

doi:10.7569/jrm.2017.634184

Cited by 7 publications

(23 citation statements)

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“…It is shown that the intensity of the amorphous bands for the neat PHBV decreased over the exposure time. In studies on PHBV exposed to moisture, thermal, and UV conditions, degradation was reported to start in the amorphous phase and then to proceed into the crystalline phase [ 25 , 26 , 94 ]. The results shown in Table 1 reveal that the degradation of neat PHBV under moisture and UV exposure occurs preferentially in the amorphous phase, as evidenced by the decrease in the corresponding carbonyl index.…”

Section: Resultsmentioning

confidence: 99%

“…Extensive research efforts have been focusing on the PHBV degradation characteristics and mechanisms when subjected to soil and microorganisms [ 11 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ], ultraviolet (UV) radiation [ 22 , 23 , 24 , 25 , 26 ], hydrolytic [ 25 , 27 , 28 , 29 , 30 , 31 , 32 ] and thermal [ 16 , 33 ] conditions. The degradation of PHBV includes several competing mechanisms: the hydrolysis of the ester group, series of reactions initiated by free radicals, crosslinking reactions, and Norrish I and II mechanisms are the most described processes [ 22 , 34 ].…”

Section: Introductionmentioning

confidence: 99%

“…The degradation of PHBV includes several competing mechanisms: the hydrolysis of the ester group, series of reactions initiated by free radicals, crosslinking reactions, and Norrish I and II mechanisms are the most described processes [ 22 , 34 ]. Due to the chain cleavage of the polymer during degradation, the molar mass, crystallinity and crystal structure, as well as the chemical/thermal/mechanical properties, are affected [ 11 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ]. The degradation rates of PHBV under simultaneous conditions can be significant.…”

Section: Introductionmentioning

confidence: 99%

“…Loading these materials can improve the biodegradability of the polymer matrix, enhance its performance and increase the range of applications. Poly(butylene succinate), polycaprolactone and PHBV nanocomposites have also gained interest because of their properties [ 24 , 25 , 26 , 32 , 43 , 54 , 55 , 56 , 57 , 58 , 59 , 60 ].…”

Section: Introductionmentioning

confidence: 99%

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Accelerated Weathering Effects on Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PHBV/TiO2 Nanocomposites

et al. 2020

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The effect of accelerated weathering on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PHBV-based nanocomposites with rutile titanium (IV) dioxide (PHBV/TiO2) was investigated. The accelerated weathering test applied consecutive steps of UV irradiation (at 340 nm and 0.76 W m−2 irradiance) and moisture at 50 °C following the ASTM D4329 standard for up to 2000 h of exposure time. The morphology, chemical structure, crystallization, as well as the mechanical and thermal properties were studied. Samples were characterized after 500, 1000, and 2000 h of exposure time. Different degradation mechanisms were proposed to occur during the weathering exposure and were confirmed based on the experimental data. The PHBV surface revealed cracks and increasing roughness with the increasing exposure time, whereas the PHBV/TiO2 nanocomposites showed surface changes only after 2000 h of accelerated weathering. The degradation of neat PHBV under moisture and UV exposure occurred preferentially in the amorphous phase. In contrast, the presence of TiO2 in the nanocomposites retarded this process, but the degradation would occur simultaneously in both the amorphous and crystalline segments of the polymer after long exposure times. The thermal stability, as well as the temperature and rate of crystallization, decreased in the absence of TiO2. TiO2 not only provided UV protection, but also restricted the physical mobility of the polymer chains, acting as a nucleating agent during the crystallization process. It also slowed down the decrease in mechanical properties. The mechanical properties were shown to gradually decrease for the PHBV/TiO2 nanocomposites, whereas a sharp drop was observed for the neat PHBV after an accelerated weathering exposure. Atomic force microscopy (AFM), using the amplitude modulation–frequency modulation (AM–FM) tool, also confirmed the mechanical changes in the surface area of the PHBV and PHBV/TiO2 samples after accelerated weathering exposure. The changes in the physical and chemical properties of PHBV/TiO2 confirm the barrier activity of TiO2 for weathering attack and its retardation of the degradation process.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Accelerated Weathering Effects on Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PHBV/TiO2 Nanocomposites

et al. 2020

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“…The results indicate an enhancement of storage modulus (G') for the bionanocomposite compared to that of Cast PHBV before gamma irradiation. This may be related to the favorable interactions and large interfacial area developed between the polymer matrix and C30B organoclay that should restrict the movement of polymer chains [16,29]. After gamma irradiation, it is observed that the storage modulus blow the α-transition of both Cast PHBV and C-PHBV/3C30B bionanocomposite, which is reduced with increasing irradiation dose (Figs.…”

Section: Thermal Stability Changesmentioning

confidence: 97%

The Effects of Gamma Irradiation on Molecular Weight, Morphology and Physical Properties of PHBV/ Cloisite 30B Bionanocomposites

Iggui

Kaci

Mahlous

et al. 2019

Journal of Renewable Materials

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In this paper, the effects of gamma irradiation on Cast poly(3hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PHBV/Cloisite 30B (C30B) (3 wt%) bionanocomposite prepared by melt compounding, were evaluated at various doses, i.e., 5, 15, 20, 50 and 100 kGy at room temperature in air. Changes in molecular weight, morphology and physical properties were investigated. The study showed that the main degradation mechanism occurring in gamma irradiation in both Cast PHBV and C-PHBV/3C30B bionanocomposite is chain scission, responsible for the decrease of molecular weight. Differential scanning calorimetry (DSC) data indicated a regular decrease in crystallization temperature, melting temperature and crystallinity index for all irradiated samples with increasing the dose. Further, DSC thermograms of both Cast PHBV and PHBV bionanocomposite exhibited double melting peaks due probably to changes in the PHBV crystal structure. Tensile and DMA data showed a reduction in Young's modulus, strength, elongation at break and storage modulus with the radiation dose; the decrease was however more pronounced for Cast PHBV. The morphological damages were much less pronounced for the PHBV bionanocomposite sample compared to Cast PHBV, for which some irregularities and defects were observed at 100 kGy. This study highlighted the ability of C30B to counterbalance the detrimental effect of radiolytic degradation on the functional properties of PHBV up to 100 kGy, thus acting as a potential anti-rad.

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In‐Depth Analysis of the Complex Interactions Induced by Nanolayered Additives in PHBV Nanocomposites

Martínez‐Rubio,

Avilés,

Pamies

et al. 2024

Macro Materials & Eng

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New nanocomposites based on biopolymer poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) are processed via extrusion, using low content of calcined hydrotalcite (CHT) and cloisite 20A (C20A) as additives (3 wt%). The aim of this work is to characterize the thermal and viscoelastic response of the structures induced by the presence of the additives. Field‐emission scanning electron microscopy and laser profilometry are utilized to analyze the effect of the additives on the surface finish of extrusion filaments, detecting a smoother surface induced by additives. A lower degradation temperature is observed via thermogravimetry for composite containing CHT (PHBV+3%CHT), while such a phenomenon is not present in composite with C20A (PHBV+3%C20A). An increase in crystallinity due to the nucleating effect of additives is measured via differential scanning calorimetry. The intercalation of the biopolymer in the layered structure of the additives is observed via X‐ray diffraction, reflecting the effective interaction in the composite matrix. The viscoelastic behavior of the samples is evaluated by means of rheology and dynamic‐mechanical analysis, showing a non‐Newtonian behavior and an enhancement of the vitreous state response. All results converge to the conclusion that the incorporation of the additives induces the formation of long‐term structures that present variable sensitivity to temperature and frequency.

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The Effects of Accelerated Photooxidation on Molecular Weight and Thermal and Mechanical Properties of PHBV/Cloisite 30B Bionanocomposites

Cited by 7 publications

References 0 publications

Accelerated Weathering Effects on Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PHBV/TiO2 Nanocomposites

Accelerated Weathering Effects on Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and PHBV/TiO2 Nanocomposites

The Effects of Gamma Irradiation on Molecular Weight, Morphology and Physical Properties of PHBV/ Cloisite 30B Bionanocomposites

In‐Depth Analysis of the Complex Interactions Induced by Nanolayered Additives in PHBV Nanocomposites

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