Markedly improved photo-oxidation stability of α form isotactic polypropylene with nodular morphology

Wu, Hao; Zhao, Ying; Su, Lili; Wang, Kezhi; Dong, Xia; Wang, Dujin

doi:10.1016/j.polymdegradstab.2021.109595

Cited by 8 publications

(9 citation statements)

References 69 publications

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“…While the amorphous phase can be divided into rigid amorphous fraction (RAF) and mobile amorphous fraction (MAF) according to the degree of coupling with crystalline phase. 8 It has been documented that the photodegradation rate is proportional to the molecular mobility in amorphous phase of polymers. 58 Therefore, considering the effect of RHCM on amorphous structure of iPP, the changes of its amorphous phase during photodegradation were investigated by DMA.…”

Section: Mechanisms Of Rhcm Improving Photodegradation Stabilitymentioning

confidence: 99%

“…3,7 Therefore, it is important to investigate the photodegradation mechanism of iPP for slowing down the photodegradation rate and prolonging the service life of its products. 5 In addition to environmental factors, the crystalline structure (crystallinity, crystal form, and crystal size) of iPP is considered to be the main microstructural factor 8 affecting the photodegradation behavior of products. At present, both inhibition and promotion effects of crystallinity on the photodegradation rate have been reported.…”

Section: Introductionmentioning

confidence: 99%

“…In addition to environmental factors, the crystalline structure (crystallinity, crystal form, and crystal size) of iPP is considered to be the main microstructural factor 8 affecting the photodegradation behavior of products. At present, both inhibition and promotion effects of crystallinity on the photodegradation rate have been reported.…”

Section: Introductionmentioning

confidence: 99%

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Effect of microstructure tuning by rapid heat cycle molding on the photodegradation behavior of isotactic polypropylene

Li,

Chen,

Xie

et al. 2024

J of Applied Polymer Sci

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Rapid heat cycling molding (RHCM) is an injection molding technique that improves the product quality of isotactic polypropylene (iPP) by tuning the microstructure, but its effect on the photodegradation stability remains to be investigated. In this work, the effect of RHCM tuned microstructure on the photodegradation behavior of iPP was investigated and compared with conventional injection molding (CIM). Differential scanning calorimetry (DSC), x‐ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), atomic force microscopy (AFM), and shore durometer (D scale) were used to examine the photodegradation behavior of iPP samples. The results showed that RHCM increased the crystallinity, crystal size, and β‐crystal content of iPP samples. With the increase of photodegradation time, iPP samples injected with RHCM showed higher stability in terms of microstructure and surface quality. The relative changes in CI and Ra of RHCM90 were reduced by 48% and 40% after 800 h of UV irradiation, respectively. In addition, the combined results of dynamic mechanical analysis (DMA) and UV–visible absorption spectrum showed that RHCM promoted the development of crystalline structure and reduced the mobility of the surface chain segments as well as UV absorption coefficient. These combined effects contributed positively to its photodegradation stability.

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Section: Mechanisms Of Rhcm Improving Photodegradation Stabilitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of microstructure tuning by rapid heat cycle molding on the photodegradation behavior of isotactic polypropylene

Li,

Chen,

Xie

et al. 2024

J of Applied Polymer Sci

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“…Plastic products are lightweight, durable, and inexpensive, making them suitable for several daily-use products . With the widespread use of plastic products, the generation and disposal of plastic waste have become a critical environmental problem. − Once plastic products are lost or disposed of in nature, photo-oxidation, thermal oxidation induced by sunlight, ,− and biodegradation by microorganisms in the sludge and ocean − accelerate the fragmentation of plastics. Finally, derelict plastics are degraded to particles with sizes ranging from several millimeters to hundreds of nanometers, which are widespread in the environment, particularly in the ocean.…”

Section: Introductionmentioning

confidence: 99%

Environmental Degradation of Nylon, Poly(ethylene terephthalate) (PET), and Poly(vinylidene fluoride) (PVDF) Fishing Line Fibers

Kajiwara

Padermshoke

et al. 2023

ACS Appl. Polym. Mater.

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Ghost fishing, caused by lost fishing lines and nets, has become a severe problem in marine environments. To eliminate ghost fishing in the ocean, the environmental degradation behavior of fishing lines must be understood. In this study, the environmental degradation of biodegradable nylon 4 fishing lines and commercial nylon 6, poly(ethylene terephthalate) (PET), and poly(vinylidene fluoride) (PVDF) fishing lines was simulated in the laboratory using an artificial weathering tester and biodegradation test in extracted seawater. To understand the degradation mechanism, the chemical and structural changes induced by photo-oxidation and biodegradation were investigated using tensile test, scanning electron microscopy, differential scanning calorimetry, gel permeation chromatography, infrared spectroscopy, and wide- and small-angle X-ray scattering. The results indicated that photo-oxidation occurred in the amorphous phase of the nylon 4, nylon 6, and PET fishing lines during ultraviolet (UV) exposure. The nylon 4 fishing lines exhibited excellent biodegradability, whereas the nylon 6, PET, and PVDF fishing lines could not be degraded by microorganisms in the extracted seawater. Both processes, i.e., photo-oxidation and biodegradation, were confined to the amorphous regions of nylon 4. Note that the PVDF fishing lines could not be degraded by UV exposure and biodegradation and, hence, should be recycled after use.

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“…As well known, isotactic polypropylene (iPP) has been widely used thermoplastic because of its comprehensive properties, such as easy of processing, low density, high heat resistance, recycle ability, and so on. [1,2] As a typical semicrystalline polymer, iPP has several different crystals: α, β, γ, and smectic crystals. [3][4][5][6] Compared with α-iPP, β-iPP exhibits excellent thermal stability and mechanical properties, which is currently arousing an intense research topic.…”

Section: Introductionmentioning

confidence: 99%

Isothermal crystallization behaviors of isotactic polypropylene with ultrasonically‐modified calcium sulfate whisker as β‐nucleating agent

Shi

Qin

et al. 2022

Polymer Engineering & Sci

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In this work, the effect of calcium sulfate whisker (CSW) and ultrasonicallymodified CSW (UCSW) on the crystal structure and isothermal crystallization of isotactic polypropylene (iPP) is studied by using differential scanning calorimetry (DSC), X-ray diffraction (XRD), and polarized optical microscopy (POM). UCSW obviously increases heterogeneous nucleation. The isothermal crystallization kinetics of pure iPP, iPP/CSW, and iPP/UCSW composites are analyzed by the Avrami method. Although the Avrami exponent (n) of these samples only changed slightly, the half crystallization time (t 1/2 ) indicates that CSW and UCSW decrease the overall crystallization time and increase the crystallization rate (R c ). POM results show that most crystals are β-iPP shaped and the spherulite size decreases significantly with the addition of UCSW. The apparent equilibrium temperature of iPP/UCSW composites is lower than that of pure iPP and iPP/CSW composites. The values of β-iPP fold surface free energy (σ e ) and the nucleation parameter (K g ) are much lower than that of α-iPP for these iPP composites. The content of β-crystal in iPP composites increases due to the addition of UCSW.

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Markedly improved photo-oxidation stability of α form isotactic polypropylene with nodular morphology

Cited by 8 publications

References 69 publications

Effect of microstructure tuning by rapid heat cycle molding on the photodegradation behavior of isotactic polypropylene

Effect of microstructure tuning by rapid heat cycle molding on the photodegradation behavior of isotactic polypropylene

Environmental Degradation of Nylon, Poly(ethylene terephthalate) (PET), and Poly(vinylidene fluoride) (PVDF) Fishing Line Fibers

Isothermal crystallization behaviors of isotactic polypropylene with ultrasonically‐modified calcium sulfate whisker as β‐nucleating agent

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