Ultraviolet Stability Research Articles

Estimating the Bioaccumulation Potential of Hydrophobic Ultraviolet Stabilizers Using Experimental Partitioning Properties.

Although hydrophobic ultraviolet (UV) stabilizers are an emerging environmental concern because of their widespread occurrence, persistence, and bioaccumulation potential, experimental values of their partitioning properties required for risk assessment are scarce. In this study, n-octanol-water partition (Kow) and lipid–water partition constants (Klipw), which are key parameters for environmental risk assessment, were experimentally determined for five selected hydrophobic UV stabilizers (UV326, UV327, UV328, UV329, and UV531) based on third-phase partitioning among polydimethylsiloxane (PDMS), water, and n-octanol/lipid. The partition constants between PDMS and water (KPDMSw), obtained using the dynamic permeation method were used to derive Kow and Klipw. The obtained log Kow and log Klipw values were in the ranges of 7.08–7.94 and 7.50–8.34, respectively, indicating that the UV stabilizers exhibited a high bioaccumulation potential in aquatic environments. The experimental Kow and Klipw values obtained in this study provide valuable information for the evaluation of the fate, distribution, bioavailability, and toxicity of the UV stabilizers in aquatic environments.

Traffic-related sources may dominate urban water contamination for many organic contaminants

Urban runoff and wastewater/sewage input are majorly responsible for the contamination of urban streams. In streams where wastewater input is not a considerable input, the importance of urban runoff as a mechanism of contaminant transport and delivery from urban surfaces to receiving waters is even more apparent. Extensive studies on two such streams in Southern Ontario, Canada yielded data on the occurrence and levels of multiple contaminant groups (polycyclic aromatic hydrocarbons and quinones, benzotriazoles (BTs), BT ultraviolet stabilizers, organophosphate esters, herbicides) and the influence of factors such as temperature, rainfall characteristics, and land use. Here, we collectively examined the data from these studies to identify any trends and further insights. Using concentration-discharge relationships, we found that the transport dynamics of many particle-bound compounds are strikingly similar to each other, and to that of suspended solids in which they were quantified, suggesting a single, predominant source. Similar urban to rural ratios across compound groups and strong correlations with road density further support the existence of a dominant source and point to traffic as this source, respectively. Although road traffic had not previously been implicated as a major source of many of the investigated compound groups, their uses suggest that traffic-related sources are very plausible. Overall, this work highlights that traffic is a major source of a surprisingly wide array of organic contaminants to urban surfaces, and subsequently to nearby streams.

Effect of copper on bioconcentration of benzotriazole ultraviolet stabilizers (BUVSs) in common carp (Cyprinus carpio)

Benzotriazole ultraviolet stabilizers (BUVSs) have received increasing attention as emerging contaminants. However, most of the existing relevant studies focused on the adverse ecological effect of BUVSs under their single exposure, information about the bioconcentration potential of BUVSs and their joint exposure with heavy metals remains scarce. In this study, we investigated the bioconcentration kinetics of 6 frequently reported BUVSs in four main tissues of common carp under different Cu concentration. The bioconcentration factors (BCFs) and half-lives (t1/2) in the fish tissues ranged from 5.73 (UV-PS in kidney) to 1076 (UV-327 in liver), and 2.19 (UV-PS in kidney) to 31.5 (UV-320 in liver) days, respectively. Under the effect of Cu, an increase in BCF values was observed, which is mainly due to the decreased depuration rate (k2). These results indicated that BUVSs accumulated in fish and that Cu can affect the bioconcentration of BUVSs. This study provides important insight into the co-exposure of heavy metal and BUVSs, contributing to the perfection of BUVSs risk assessment.

Ternary Organic Solar Cell with 1750 h Half Lifetime Under Ultraviolet Irradiation with Solar Intensity

The ultraviolet (UV) radiation in the solar spectrum causes most of the decay under sunlight for solar cells based on organic photovoltaics (OPV). One‐year outdoor lifetime still remains challenging for OPV. The lifetime of 2000 h under continuous laboratory light corresponds to a 1 year outdoor lifetime. Herein, the stability of the OPVs is studied under continuous irradiation by a UV light emitting diode of 365 nm with a long tracking time. The intensity of 50 W m−2 is the same as the sunlight UV. The compositions of the active layer and cathode interfacial layer are sensitive to UV irradiation. In general, ternary devices have better UV stability than binary devices. In particular, a good stability is achieved for the ternary device based on the high‐performance blend with poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl‐3‐fluoro)thiophen‐2‐yl)‐benzo[1,2‐b:4,5‐b']dithiophene))‐alt‐(5,5‐(1',3'‐di‐2‐thienyl‐5',7'‐bis(2‐ethylhexyl)benzo[1',2'‐c:4',5'‐c']dithiophene‐4,8‐dione)] (PM6) as the donor. The acceptor is 2,2'‐((2Z,2'Z)‐((12,13‐bis(2‐ethylhexyl)‐3,9‐diundecyl‐12,13‐dihydro‐[1,2,5]thiadiazolo[3,4‐e]thieno[2",3":4',5']thieno[2',3':4,5]pyrrolo[3,2‐g]thieno[2',3':4,5]thieno[3,2‐b]indole‐2,10‐diyl)bis(methanylylidene))bis(5,6‐difluoro‐3‐oxo‐2,3‐dihydro‐1H‐indene‐2,1‐diylidene))dimalononitrile (Y6). The fullerene derivative [6,6]‐phenyl C71‐butyric acid methyl ester (PC71BM) is added as the second acceptor, whereas a polymer poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b:4,5‐b']dithiophene))‐co‐(1,3‐di(5‐thiophene‐2‐yl)‐5,7‐bis(2‐ethylhexyl)benzo[1,2‐c:4,5‐c']dithiophene‐4,8‐dione)] (PBDB‐T) is added as the second donor. For the PM6:Y6 ternary device, the UV half lifetime is 1750 h, which is close to the 2000 h target set by the outdoor of a 1 year lifetime.

Structurally Tolerance-Factor-Tuned Metal Halide Nanocrystals for Environmentally Stable and Efficient Red Light-Emitting Diodes.

Black phase CsPbI3, naturally possessing the superiority of high radiative recombination efficiency and narrow emission line width, shows promise for commercial applications of red perovskite light-emitting diodes (PeLEDs). However, the metastable black phase CsPbI3 with a marginal tolerance factor (t) of 0.81 would easily convert to the nonoptical yellow phase. Herein, we demonstrate the strategy of partial substitution of larger dimethylammonium cation (DMA+) for Cs+ to achieve the stable tolerance factor of 0.903 for greatly improved Cs0.7DMA0.3PbI3 nanocrystals. These NCs present a superior ultraviolet (UV) irradiation stability by retaining 80% of the initial photoluminescence intensity after 5 h, which is much better than that of its counterparts (retaining 30%). Based on this, the as-developed red PeLEDs demonstrate remarkable luminance of 1258 cd/m2 and external quantum efficiency of 3.39%, which are almost 6 times and 3 times that of its counterparts, respectively (203 cd/m2 and 1.28%). This strategy may pave the way to improving the stability and efficiency of PeLEDs.

Quantitation of Phenolic Benzotriazole Class Compounds in Plasma by Liquid Chromatography–Tandem Mass Spectrometry (LC-MS/MS)

Phenolic benzotriazoles are used as ultraviolet stabilizers in consumer products and have been detected in the environment suggesting potential human exposure. Phenolic benzotriazoles were nominated to the Division of National Toxicology Program for testing based on their potential widespread human exposure and lack of adequate toxicity data. Nine chemicals were selected for toxicological evaluation, representing unsubstituted (2-(2H-benzotriazole-2-yl)phenol, (P-BZT)), monosubstituted (drometrizole; 2-(2H-benzotriazol-2-yl)-4-tert-butylphenol (tBu-BZT); octrizole), disubstituted (2-(2H-benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (diMeEtPh-BZT), 2-(2H-benzotriazol-2-yl)-4,6-bis(1,1-dimethylpropyl)phenol (ditPe-BZT); 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxybenzenepropanoic acid, octylester (tBuPrOcEst-BZT) and halogenated trisubstituted (bumetrizole; 2-(5-chloro-2H-benzotriazol-2-yl)-4,6-bis(1,1-dimethylethyl)phenol (ditBuCl-BZT)) compounds. Different extraction methods were utilized and methods were developed to determine phenolic benzotriazoles by quantitating free (unconjugated parent) and total (free and conjugated parent) analytes in plasma of rats to aid in interpretation of toxicity data, understanding of absorption, distribution, metabolism, and excretion differences. The calibration standard range was from 1 to 500 ng/mL for free analytes and 1 to 1000 ng/mL for total analytes. The methods were linear (r2 ≥ 0.99). The accuracy was determined as the relative error (RE) and ranged from −18.2 to +17.8, and precision as the relative standard deviation (RSD) and ranged from 0.0 to 20.1% for both free and total plasma calibration standards, respectively. The limits of quantitation were ≤5.0 and 10.0 ng/mL and limit of detection ≤ 1.2 and 2.0 ng/mL, for free and total analytes, respectively. These results demonstrate that the methods are suitable for quantitation of free and total analytes in rat plasma.

High-efficiency and ultraviolet stable carbon-based CsPbIBr2 solar cells from single crystal three-dimensional anatase titanium dioxide nanoarrays with ultraviolet light shielding function

TiO2 is commonly used to prepare electron transport layers (ETLs) in perovskite solar cells (PSCs). However, conventional TiO2 ETLs suffer from low electron mobility and charge recombination. Here, we report the direct growth of TiO2 ETLs on fluorine doped conductive (FTO) glasses with titanium tetrafluoride (TiF4) as the reactant by hydrothermal method. The TiO2 ETLs have pure anatase phase, single crystal structure and three-dimensional (3D) nanoarrays morphology. This 3D-TiO2 ETLs mainly consist of thermodynamically stable surfaces {101} and more reactive surfaces {001}. Compared with the conventional TiO2 ETLs, the 3D-TiO2 ETLs can effectively optimize energy level matching and charge transfer dynamics. The special morphology of 3D-TiO2 ETLs can well assist to form high quality CsPbIBr2 with larger crystal grains. The champion CsPbIBr2 PSC with 3D-TiO2 ETL achieves an efficiency as high as 10.65%, which is equal to the one with hole-transport and Au electrode structure (10.79%) and much higher than the pristine one (7.16%) with the conventional TiO2 ETL. Furthermore, the 3D-TiO2 ETLs show ultraviolet (UV) shielding function, which can effectively overcome the UV instability defect of conventional TiO2 ETLs and obviously enhance UV stability of CsPbIBr2 and the corresponding PSCs. Therefore, the 3D-TiO2 ETLs can be good candidates for preparing high-efficiency and UV stable carbon-based CsPbIBr2 PSCs.

Design of Organic-Free Superhydrophobic TiO2 with Ultraviolet Stability or Ultraviolet-Induced Switchable Wettability.

Superhydrophobic TiO2 with great application potential is mainly obtained by surface modification with low surface energy organics, which is easily degraded under sunlight irradiation, which results in the loss of superhydrophobic properties. Herein, we developed a room-temperature pulsed chemical vapor deposition (pulsed CVD) method to develop amorphous TiO2-deposited TiO2 nanoparticles. The ultraviolet stability/ultraviolet-induced reversible wettability switch had been simultaneously realized by different and controllable deposition cycles of amorphous TiO2. The superhydrophobic properties of the organic-free TiO2 were determined by the micrometer-nanometer-sub-nanometer multiscale structure, the multiscale pore structure, and the large Young's contact angle resulting from carboxylic acid adsorption. Also, we found that the adsorption rate and adsorption stability of oxygen and water at the surface oxygen vacancies were the key to facilitate the reversible switching between superhydrophilic and superhydrophobic states, which was well demonstrated by experimental characterization and theoretical simulation. In addition, we also found that the resistance of dense amorphous TiO2 films on the TiO2 surface to the migration of photogenerated electrons and holes was the key to maintain the stable superhydrophobic properties of superhydrophobic TiO2 under ultraviolet illumination. The powders were strongly ground and the coating surface was rubbed on the surface of the sandpaper, which still maintained superhydrophobic properties, providing favorable conditions for the application of superhydrophobic TiO2. This work modulates the ultraviolet stability and dark/ultraviolet-induced switchable superhydrophobicity/superhydrophilicity of coated TiO2 by simply adjusting the number of deposition times in a pulsed CVD process for the first time, thus contributing to the development of organic-free superhydrophobic TiO2.

Benzotriazole Ultraviolet Stabilizers Promote Breast Cancer Cell Proliferation via Activating Estrogen-Related Receptors α and γ at Human-Relevant Levels

Benzotriazole ultraviolet stabilizers (BUVSs) are ubiquitous emerging pollutants that have been reported to show estrogenic disruption effects through interaction with the classic estrogen receptors (ERs) in the fashion of low activity. The present study aims at revealing the potential disruption mechanism via estrogen-related receptors α and γ (ERRα and ERRγ) pathways. By the competitive binding assay, we first found that BUVSs bond to ERRγ ligand binding domain (ERRγ-LBD) with Kd ranging from 0.66 to 19.27 μM. According to the results of reporter gene assays, the transcriptional activities of ERRα and ERRγ were promoted by most tested BUVSs with the lowest observed effective concentrations (LOEC) from 10 to 100 nM, which are in the range of human exposure levels. At 1 μM, most tested BUVSs showed higher agonistic activity toward ERRγ than ERRα. The most effective two BUVSs promoted the MCF-7 proliferation dependent on ERRα and ERRγ with a LOEC of 100 nM. The molecular dynamics simulation showed that most studied BUVSs had lower binding free energy with ERRγ than with ERRα. The structure-activity relationship analysis revealed that molecular polarizability, electron-donating ability, ionization potential, and softness were the main structural factors impacting the binding of BUVSs with ERRγ. Overall, our results provide novel insights into the estrogenic disruption effects of BUVSs.

A Critical Review of the Performance and Soil Biodegradability Profiles of Biobased Natural and Chemically Synthesized Polymers in Industrial Applications.

This review explores biobased polymers for industrial applications, their end fate, and most importantly, origin and key aspects enabling soil biodegradation. The physicochemical properties of biobased synthetic and natural polymers and the primary factors governing degradation are explored. Current and future biobased systems and factors allowing for equivalent comparisons of degradation and possible sources for engineering improved biodegradation are reviewed. Factors impacting ultraviolet (UV) stability of biopolymers have been described including methods to enhance photoresistance and impact on biodegradation. It discusses end-fate of biopolymers in soil and impact of residues on soil health. A limited number of studies examine side effects (e.g., microbial toxicity) from soil biodegradation of composites and biopolymers. Currently available standards for biodegradation and composting have been described with limitations and scope for improvements. Finally, design considerations and implications for sustainable polymers used, under consideration, and to be considered within the context of a rational biodegradable strategy are elaborated.

Ultraviolet Stability for QED in $$d=3$$

We continue the study of the ultraviolet problem for QED in \(d=3\) using Balaban’s formulation of the renormalization group. The model is defined on a fine toroidal lattice and we seek control as the lattice spacing goes to zero. Drawing on earlier papers in the series the renormalization group flow is completely controlled for weak coupling. The main result is an ultraviolet stability bound in a fixed finite volume.

Dual interfacial engineering to improve ultraviolet and near-infrared light harvesting for efficient and stable perovskite solar cells

The light loss caused by the incomplete utilization of the solar energy spectrum is a key factor that impedes the photoelectric conversion efficiency of perovskite solar cells (PSCs). Hence, reducing the light escape through enhancing the utilization of ultraviolet (UV) light, and expanding the response of PSCs in the near-infrared (NIR) range is the key factor to further improve the photoelectric conversion efficiency (PCE) of PSCs. However, there is a lack of literature on engineering UV and NIR light harvesting at the same time. Herein, the NaYF4:Ce,Tb@NaYF4 core–shell nanocrystals with efficient photon downconversion ability from UV to visible are designed to be embedded in the electron transporting layer (ETL), which serves as the photon downconverters and defect passivators, successfully improving the light response in both UV and visible region. The CIGSe quantum dots (QDs) with excellent infrared light harvesting ability, together with the plasmonic Au nanorods (NRs), are assembled in the hole transporting layer (HTL) to expand and improve the NIR light harvesting. The light response of the PSCs was successfully broadened to the NIR region from 800 to 920 nm. As a result, the champion PSC device insulating with NaYF4:Ce,Tb@NaYF4 nanocrystals and CIGSe QDs demonstrates a remarkably increased PCE from 19.38% to 22.60%. The modified PSC devices also demonstrate highly improved UV and long-term stability. This work suggests a universal strategy to improve the UV and near-infrared light harvesting of PSCs, which is of great importance for fabricating PSCs with response to full spectrum.

Innovative Skin Product O/W Emulsions Containing Lignin, Multiwall Carbon Nanotubes and Graphene Oxide Nanoadditives with Enhanced Sun Protection Factor and UV Stability Properties

In the present study, oil-in-water (O/W) sunscreen emulsions were prepared containing different portions of lignin (LGN), multiwall carbon nanotubes (MWCNTs) and graphene oxide (GO) nanoadditives. The stability in terms of pH and viscosity of emulsions was thoroughly studied for up to 90 days, exhibiting high stability for all produced O/W emulsions. The antioxidant activity of emulsions was also analyzed, presenting excellent antioxidant properties for the emulsion that contains LGN due to its phenolic compounds. Moreover, the emulsions were evaluated for their ultraviolet (UV) radiation protection ability in terms of sun protection factor (SPF) and UV stability. SPF values varied between 6.48 and 21.24 while the emulsion containing 2% w/v MWCNTs showed the highest SPF index and all samples demonstrated great UV stability. This work hopefully aims to contributing to the research of more organic additives for cosmetic application with various purposes.

Plastics in robots: a degradation study of a humanoid skin mask made of soft urethane elastomer

Understanding the degradation of plastic materials is a big challenge for curators, conservators and conservation scientists in museums worldwide aiming to preserve their collections due to the variety of formulations of synthetic polymers and pigments. The conservation of polyurethane (PUR) based objects is challenging because they can suffer from extensive degradation. Particularly PUR elastomers can degrade shortly after their production, as occurred to the mask of the Japanese robot SAYA, which within 8 years suffered from two large tears, discoloration and stickiness. This research aims at studying the degradation phenomena of the androids’ synthetic skin. Better knowledge of the chemical composition of the mask and the chemical and physical decay will contribute to planning a suitable stabilization treatment. Within a multi-analytical approach, colorimetric and microscopic investigations highlighted discolored areas, which showed further color changes within a five months monitoring campaign, confirming the instability of the material likely due to ongoing degradation. Raman microscopy allowed the identification of Pigment White 6 (titanium dioxide TiO2) in the anatase form, known to promote the photosensitivity of PUR substrates towards ultraviolet (UV) light. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy identified the PUR composition of the mask, the presence of phthalates as plasticizers and suggested the formation of quinone chromophores in the polymer structure as a result of photo-oxidation, possibly responsible for the mask yellowing. Evolved gas analysis-mass spectrometry (EGA-MS) and double-shot-gas chromatography/mass spectrometry (TD/Py–GC/MS) analyses support the characterization of the formulation of the mask as being made of methylene diphenyl diisocyanate (MDI) PUR ether elastomer. Plasticizers in high concentration, mainly diisononyl phthalate (DINP) and bis(2-ethylhexyl)phthalate (DEHP), and the UV stabilizer Tinuvin 328 were also detected. In addition, the presence of styrene-acrylonitrile (SAN) could also contribute to the mask’s chemical instability. More amount of UV stabilizer and phthalates were detected at the surface (contributing to its stickiness) than in the inner core. The degradation of the mask results from the light susceptibility of MDI PUR ether and SAN, as well as the higher photochemical activity of anatase. The mask was transferred on to a mannequin and placed in the storage area to prevent light exposure and photo-oxidation. As loose edges had to be stabilized, tests were conducted and adhesive stripes glued with a PUR dispersion were selected for keeping the head’s shape. The novelty of this study is the implementation of conservation science on the study of androids with PUR elastomeric components in robotic collections, which are becoming increasingly popular in technical museums, however still seldomly studied.

The Accelerated Aging Impact on Mechanical and Thermal Properties of Polypropylene Composites with Sedimentary Rock Opoka-Hybrid Natural Filler.

This paper presents the impact of accelerated aging on selected mechanical and thermal properties of isotactic polypropylene (iPP) composites filled with sedimentary hybrid natural filler-Opoka rock. The filler was used in two forms: an industrial raw material originating as a subsieve fraction natural material, and a rock calcinated at 1000 °C for production of phosphorous sorbents. Fillers were incorporated with constant amount of 5 wt % of the resulting composite, and the material was subjected to accelerated weathering tests with different exposition times. The neat polypropylene and composites with calcium carbonate as a reference filler material were used for comparison. The aim of the research was to determine the possibility of using the Opoka rock as a new hybrid filler for polypropylene, which could be an alternative to the widely used calcium carbonate and silica. The thermal, mechanical, and structural properties were evaluated by means of differential scanning calorimetry (DSC), tensile tests, scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy with attenuated total reflectance (FTIR/ATR) prior to and after accelerated aging. As a result, it was found that the composites of polypropylene with Opoka were characterized by similar or higher functional properties and higher resistance to photodegradation compared to composites with conventional calcium carbonate. The results of measurements of mechanical properties, structural and surface changes, and the carbonyl index as a function of accelerated aging proved that Opoka was an effective ultraviolet (UV) stabilizer, significantly exceeding the reference calcium carbonate in this respect. The new hybrid filler of natural origin in the form of Opoka can therefore be used not only as a typical powder filler, but above all as a UV blocker/stabilizer, thus extending the life of polypropylene composites, especially for outdoor applications.

Age-related accumulation of persistent organic chemicals in captive king penguins (Aptenodytes patagonicus).

Persistent organic chemicals are non-biodegradable in nature and have a tendency to bioaccumulate in the top organisms of the food chain. We measured persistent organic chemicals, including polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (DDE), and benzotriazole-based ultraviolet stabilizers (UV-BTs), in the serum of captive king penguins (Aptenodytes patagonicus) using gas chromatography with an electron capture detector and mass spectrometry to examine their age-related accumulation. PCBs, DDE, UV-PS, and UV-9 were detected in the blood of captive king penguins, and the concentrations of total PCBs, DDE, and UV-9 were positively correlated with age. These results suggest that there is a similar age-related accumulation of persistent organic chemicals in marine birds in the wild, and that older individuals are at a higher risk of contamination.

Inverted Planar Heterojunction Perovskite Solar Cells with High Ultraviolet Stability

Inverted Planar Heterojunction Perovskite Solar Cells with High Ultraviolet Stability

Equilibrium leaching of selected ultraviolet stabilizers from plastic products

Despite the importance of (micro)plastics in the release of plastic additives, the leaching mechanism of organic plastic additives from various plastic materials is poorly understood. In this study, the equilibrium leaching of five highly hydrophobic ultraviolet (UV) stabilizers (UV326, UV327, UV328, UV329, and UV531) from three plastics (low-density polyethylene (LDPE), polyethylene terephthalate (PET), and polystyrene (PS)), was investigated employing acetonitrile-water cosolvent systems. Their extrapolated water solubilities were in the 0.15–0.54 μg L−1 range, limiting their transport as “dissolved” in water and (micro)plastics are likely those particulate carriers. The equilibrium leaching of UV stabilizers from plastics was better explained by the Flory-Huggins model incorporating the nonideal behavior caused by the size disparity between UV stabilizers and polymer materials and their compatibility. Specifically, leaching of UV stabilizers from LDPE showed a positive deviation from Raoult’s law, whereas slight negative deviations were observed in PET and PS. In addition, the equilibrium concentration of the benzotriazoles in LDPE increased linearly with the volume fraction up to only 0.4%. These observations could be explained by the unfavorable interactions of UV stabilizers with polyethylene, indicating that polymer type should be also important when evaluating the fate of hydrophobic additives. Because equilibrium distribution of additives between (micro)plastics and water is crucial for evaluating the fate and transport of hydrophobic plastic additives, further studies on the leaching equilibrium of various additives from different plastic materials are necessary.

One-Pot Preparation of Benzotriazole-Modified Porous Silica for Durable UVA Absorption Ability.

The durable application of poly(butylene adipate-co-terephthalate) (PBAT) under atmospheric conditions is restricted by its poor ultraviolet (UV) stability. To improve the anti-aging capacity to UV radiation of the PBAT film, we describe a straightforward and highly producible synthesis of UV-resistant dendrimeric porous silica nanospheres (SiO2–HBT) by adding benzotriazole as a pore-expanding agent, more importantly demonstrating its detailed mechanism. Well-dispersed silica nanospheres are shown to offer the release property for benzotriazole triggered by UV and heat irradiation while durable UV protection due to the supplementary of benzotriazole in the PBAT matrix. With benzotriazole compensation, the halving period of elongation at break performance was extended from about 15 to 48 h. Combined with gel content and gel permeation chromatography analyses, it was inferred that the process of crosslinking resulting from Norrish I can be effectively minimized by the action of SiO2–HBT. The design of modified release strategy realizes the durable UV absorption ability of the hydroxyphenyl benzotriazole class of photostabilizers in particular but more generally highlights an important adding method that should be considered when utilizing a photostabilizer.

Modifications of Polymers through the Addition of Ultraviolet Absorbers to Reduce the Aging Effect of Accelerated and Natural Irradiation.

The photooxidative degradation process of plastics caused by ultraviolet irradiation leads to bond breaking, crosslinking, the elimination of volatiles, formation of free radicals, and decreases in weight and molecular weight. Photodegradation deteriorates both the mechanical and physical properties of plastics and affects their predicted life use, in particular for applications in harsh environments. Plastics have many benefits, while on the other hand, they have numerous disadvantages, such as photodegradation and photooxidation in harsh environments and the release of toxic substances due to the leaching of some components, which have a negative effect on living organisms. Therefore, attention is paid to the design and use of safe, plastic, ultraviolet stabilizers that do not pose a danger to the environment if released. Plastic ultraviolet photostabilizers act as efficient light screeners (absorbers or pigments), excited-state deactivators (quenchers), hydroperoxide decomposers, and radical scavengers. Ultraviolet absorbers are cheap to produce, can be used in low concentrations, mix well with polymers to produce a homogenous matrix, and do not alter the color of polymers. Recently, polyphosphates, Schiff bases, and organometallic complexes were synthesized and used as potential ultraviolet absorbers for polymeric materials. They reduced the damage caused by accelerated and natural ultraviolet aging, which was confirmed by inspecting the surface morphology of irradiated polymeric films. For example, atomic force microscopy revealed that the roughness factor of polymers’ irradiated surfaces was improved significantly in the presence of ultraviolet absorbers. In addition, the investigation of the surface of irradiated polymers using scanning electron microscopy showed a high degree of homogeneity and the appearance of pores that were different in size and shape. The current work surveys for the first time the use of newly synthesized, ultraviolet absorbers as additives to enhance the photostability of polymeric materials and, in particular, polyvinyl chloride and polystyrene, based mainly on our own recent work in the field.