Formation of craze-like pattern in polypropylene UV-induced surface cracking

Freitas, Amanda de Sousa Martinez de; Rodrigues, Jéssica S.; Botaro, Vagner Roberto; Lemes, Ana Paula; Cruz, Sandra Andréa; Waldman, Walter R.

doi:10.1007/s10965-022-03357-z

Cited by 12 publications

(10 citation statements)

References 44 publications

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“…UV‐A (present in solar light) and UV‐C (used for shorter photodegradation experiments due to its higher energy) are ranges of the ultraviolet wavelength spectra that produce similar final outputs (e.g. breaking of polymer chains, volatile organic compounds production, reactive oxygen species or surface cracking) (De Freitas et al, 2022; Wu et al, 2023), and therefore could be compared. Each plastic type was photodegraded during 2 weeks; except PET film, which was photodegraded during 4 weeks as these films showed an extremely slow rate of degradation after FTIR analyses.…”

Section: Methodsmentioning

confidence: 99%

Photodegradation modifies microplastic effects on soil properties and plant performance

Lozano,

Gordillo‐Rocha,

Waldman

et al. 2023

Journal of Applied Ecology

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Microplastics (MPs) in soil affect plant–soil systems depending on their shape and polymer type. However, previous research has not yet considered the effects of degraded plastics, which are the plastic materials actually present in the environment. We selected eight MPs representing different shapes (fibres, films and foams) and polymer types, and exposed them to UV‐C degradation. Each MP was mixed with soil at a concentration of 0.4% (w/w). The phytometer Daucus carota grew in each pot. At harvest, soil properties and plant biomass were measured. Photodegradation altered MP physical and chemical properties, impacting plant–soil systems. MP degradation effects on plant and soil were observed with fibres and foams, but there were negligible effects with films. The latter could be explained by the polymer structure of films and manufacturer's additives, potentially delaying their degradation. Degraded fibres increased soil respiration more than their non‐degraded counterparts, as photodegradation increased the positive effects of fibres on soil water retention. The emergence of oxygenated groups during degradation may have increased the hydrophilicity of fibres, enhancing their ability to retain water. Degraded foams increased soil respiration, which could be related to the possible leaching of organic substances with lower partition coefficients, which may promote soil microbial activity. In contrast, degraded foams decreased soil aggregation, likely as degradation produced larger holes increasing their permeability. Also, the increase in hydrophilic molecules could have decreased soil particle cohesiveness. Degraded fibres and foams increased shoot and root mass as a result of MP effects on soil properties. Photodegraded MPs affected root traits, which could be linked to MP effects on soil water status and plant coping strategies. Synthesis and applications. Photodegradation can intensify the effects that microplastics (MPs) have on plant–soil systems, which would have frequently been underestimated had we only worked with pristine MPs. Plastic companies, agricultural practitioners and researchers should consider that plastics are being degraded as they enter the soil. Policies should promote practices to minimize MP accumulation in soils and ensure their proper disposal.

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Section: Methodsmentioning

confidence: 99%

Photodegradation modifies microplastic effects on soil properties and plant performance

Lozano,

Gordillo‐Rocha,

Waldman

et al. 2023

Journal of Applied Ecology

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“…After 200 h of photodegradation, the characteristic peaks of both α-phase and β-phase are enhanced, which are consistent with the DSC results, indicating that X c of samples increases due to the chemical crystallization. 46 However, the intensity of characteristic peaks gradually decreases with increasing photodegradation time, which indicates a decrease in the content of α-crystal and β-crystal. The variation of K β is quantified in Figure 7a, and it decreases only after a certain UV light induction period.…”

Section: Effect Of Rhcm On Photodegradationmentioning

confidence: 97%

“…It is the main absorption peak of photodegradation, indicating that iPP produced carbonyl-containing degradation by-products under UV light. 46 The areas of these carbonyl absorption bands increase with the increase of UV exposure time, but there is a great difference between CIM and RHCM. The carbonyl peak area of CIM is larger than that of RHCM60 and RHCM90, and CIM shows the strongest absorption intensity after 800 h of UV light exposure, indicating the maximum photodegradation.…”

Section: Effect Of Rhcm On Photodegradationmentioning

confidence: 99%

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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“…After this time, the tensile strength decreased to 20% of the original value (dynamic mechanical thermal analysis) and the presence of hydroxyl and carboxyl functional groups was confirmed by Fourier transform infrared spectroscopy. The decrease in tensile strength was very significant, but the irradiation time was extreme [79]. Grause et al [80] provided an overview of the chemical changes of polyolefins in the presence of UV radiation and oxygen.…”

Section: Effect Of Physical Plasma and Uv C Radiation On Plasticsmentioning

confidence: 99%

“…Another situation occurs with samples modified by UV C radiation, which can disrupt the inner layers of the sample material. The published results showed that a decrease in the mechanical properties due to UV C radiation can be expected for PP, on the contrary, PVDF should be stable [79][80][81][82]. Information on the stability of PES against UV C radiation has not been found.…”

Section: Mechanical Properties Of Modified Meshesmentioning

confidence: 99%

Surface Modification of Artificial Implants by Hybrid Nanolayers: Antimicrobial Surface Finishing and Strength Tests

Škach,

Šlamborová,

Jelínek Šourková

et al. 2023

Eur Surg Res

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Introduction: The aim of this work is the evaluation of surface modification in surgery of normally used hernia implants and thus improving their antimicrobial properties. The modification consisted of applying hybrid nanolayers with immobilized antiseptic substances (metal cations of Ag, Cu and Zn) by sol-gel method which ensures prolonged effect of these substances and thus enables a greater resistance of the implant towards infection. In this work attention is drawn to the issue of applying hybrid nanolayers, activation of mesh surfaces by physical plasma modification or UV C radiation and influence of these modifications on the mechanical properties of the final meshes. Next work will continue concentrating on the issue of antimicrobial efficacy and eventual toxicity of the prepared layers. Materials and methods: Present day materials of the most commonly used types of implants for reconstruction of the abdominal wall in surgery (PP, PES, PVDF) were tested. Optimum conditions of application of nanolayers by sol-gel method and their thermal stabilization were examined first. Surface modification was verified by scanning electron microscope. The surface of implants was first activated for better adhesion by plasma treatment or UV radiation after preliminary tests. Maximum strength and ductility after activation and hybrid nanolayer modification were objectively measured on a universal Testometric tensile testing machine. Results: The results of surface activation of the meshes (by both plasma treatment or UV C radiation) provided similar and satisfactory results, particular conditions differed based on the type of material of the mesh. Usage of antimicrobial sol AD30 diluted by isopropyl alcohol in 1: 1 proportion appear to be optimal. All tested cases of meshes activated by plasma modification or UV C radiation and with applied nanolayer concluded in a slight reduction of mechanical properties in modified meshes in comparison with the original ones. However, a slight reduction of test values were not of clinical importance. Conclusion: It was verified that surface modification of implants by sol-gel method is effective and technically possible, providing hopeful results.

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Formation of craze-like pattern in polypropylene UV-induced surface cracking

Cited by 12 publications

References 44 publications

Photodegradation modifies microplastic effects on soil properties and plant performance

Photodegradation modifies microplastic effects on soil properties and plant performance

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

Surface Modification of Artificial Implants by Hybrid Nanolayers: Antimicrobial Surface Finishing and Strength Tests

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