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A kind of phosphorus-doped carbon dots with flame retardancy was made from biphenylamine and guanidine phosphate by a simple hydrothermal method. The surface chemical structure, morphology, and optical property of the as-synthesized MPD-GP-CQDs were characterized by Fourier transform infrared spectrometry, Field emission transmission electron microscopy, and fluorescence spectroscopy, respectively. And then the MPD-GP-CQDs were added to poly-(vinyl alcohol) (PVA) to prepare functional PVA composite film. The effect of MPD-GP-CQDs with different additions on the thermal, optical, and mechanical properties as well as flame retardancy of PVA composite film were explored by thermogravimetric analysis, differential scanning calorimetry, UV–vis spectroscopy, universal tensile test, vertical combustion test (UL-94), limiting oxygen index (LOI), microcalorimeter, etc. It showed that the addition of MPD-GP-CQDs not only endowed PVA film with flame retardancy but also improved its UV shielding and mechanical properties. The phosphorus content played a key role in the modification. As the added MPD-GP-CQDs increased, the flame retardant performance gradually increased. When 12.5% MPD-GP-CQDs was added, the UL-94 vertical combustion test rating of the MPD-GP-CQDs-PVA composite film reached VTM-0, and the LOI value was 30.8%. In addition, the transmittance of the MPD-GP-CQDs-PVA composite film in the UV-A band decreased to 35.3%, showing good UV shielding effect. These results suggested that the phosphorus-doped composite carbon dots had potential application in the development of some polymer materials such as multifunctional PVA films. [ABSTRACT FROM AUTHOR]

A novel in situ chemical upcycling strategy for plastic waste is proposed by the customized diphenylacetylene monomer with dual photo‐response. That is, diphenylacetylene reactive monomers are in situ inserted into the macromolecular chain of polyethylene terephthalate (PET) plastics/fibers through one‐pot transesterification of slight‐depolymerization and re‐polymerization. On the one hand, the diphenylacetylene group absorbs short‐wave high‐energy UV rays and then releases long‐wave low‐energy harmless fluorescence. On the other hand, the UV‐induced photo‐crosslinking reaction among diphenylacetylene groups produces extended π‐conjugated structure, resulting in a red‐shift (due to decreased HOMO–LUMO separation) in the UV absorption band and locked crosslink points between PET chains. Therefore, with increasing UV exposure time, the upcycled PET plastics exhibit reverse enhanced UV resistance and mechanical strength (superior to original performance), instead of serious UV‐photodegradation and damaged performance. This upcycling strategy at oligomer‐scale not only provides a new idea for traditional plastic recycling, but also solves the common problem of gradual degradation of polymer performance during use. [ABSTRACT FROM AUTHOR]

The present study has been conducted to investigate the protective effect of graphitic carbon nitride quantum dots (CNQDs) against high energetic and harmful ultraviolet (UV) rays in addition to strengthening impact of CNQDs over mechanical and viscoelastic properties of unsaturated polyester (UP). To achieve this purpose, CNQDs were synthesized using citric acid and extra urea via microwave-assisted method. Afterwards, several percentages of CNQDs (0.25, 0.5 and 0.75 wt%) were added to UP and after curing process, UP/CNQDs nanocomposites were obtained with different percentages. By certain microscopic and spectroscopic tests, correctness of CNQDs formation and various features of UP/CNQDs nanocomposites were examined. Adding CNQDs to the matrix of polyester resin allowed creation of nanocomposites with fluorescence emission ability, also blockage of UV rays by the strengthened samples. Strengthening UP by CNQDs resulted in growth of thermal stability, improvement of tensile strength, 10%–15% increase in flexibility, and progress in viscoelastic characteristics including storage modulus, Tg and cross-linking density. [ABSTRACT FROM AUTHOR]

Antarctica is an untapped reservoir of bacterial communities, which are able to adapt to a huge variety of strategies to cope with extreme conditions and, therefore, are capable of producing potentially valuable compounds for biotechnological applications. In this study, 31 UV-resistant bacteria collected from different Antarctic aquatic environments (surface sea waters/ice and shallow lake sediments) were isolated by UV-C assay and subsequently identified. A phylogenetic analysis based on 16S rRNA gene sequence similarities showed that the isolates were affiliated with Proteobacteria, Actinobacteria and Firmicutes phyla, and they were clustered into 15 bacterial genera, 5 of which were Gram negative (Brevundimonas, Qipengyuania, Sphingorhabdus, Sphingobium, and Psychrobacter) and 10 of which were Gram positive (Staphylococcus, Bacillus, Mesobacillus, Kocuria, Gordonia, Rhodococcus, Micrococcus, Arthrobacter, Agrococcus, and Salinibacterium). Strains belonging to Proteobacteria and Actinobacteria phyla were the most abundant species in all environments. The genus Psychrobacter was dominant in all collection sites, whereas bacteria belonging to Actinobacteria appeared to be the most diverse and rich in terms of species among the investigated sites. Many of these isolates (20 of 31 isolates) were pigmented. Bacterial pigments, which are generally carotenoid-type compounds, are often involved in the protection of cells against the negative effects of UV radiation. For this reason, these pigments may help bacteria to successfully tolerate Antarctic extreme conditions of low temperature and harmful levels of UV radiation. [ABSTRACT FROM AUTHOR]

Bacillus thuringiensis (Bt) is a widely used microbial pesticide. However, its duration of effectiveness is greatly shortened due to the irradiation of ultraviolet rays, which seriously hinders the application of Bt preparations. Therefore, it is of great importance to study the resistance mechanism of Bt to UV at the molecular level to improve the UV-resistance of Bt strains. In order to know the functional genes in the UV resistance, the genome of UV-induced mutant Bt LLP29-M19 was re-sequenced and compared with the original strain Bt LLP29. It was shown that there were 1318 SNPs, 31 InDels, and 206 SV between the mutant strain and the original strain Bt LLP29 after UV irradiation, which were then analyzed for gene annotation. Additionally, a mutated gene named yqhH, a member of helicase superfamily II, was detected as an important candidate. Then, yqhH was expressed and purified successfully. Through the result of the enzymatic activity in vitro, yqhH was found to have ATP hydrolase and helicase activities. In order to further verify its function, the yqhH gene was knocked out and complemented by homologous recombinant gene knockout technology. The survival rate of the knockout mutant strain Bt LLP29-ΔyqhH was significantly lower than that of the original strain Bt LLP29 and the back-complemented strain Bt LLP29-ΔyqhH-R after treated with UV. Meanwhile, the total helicase activity was not significantly different on whether Bt carried yqhH or not. All of these greatly enrich important molecular mechanisms of Bt when it is in UV stress. [ABSTRACT FROM AUTHOR]

Purpose. Research of the influence of adding nanosized additives and ultraviolet stabilizers to thinlayer coatings on their destruction under the action of ultraviolet radiation. Methodology. In the work, a styrene-acrylic copolymer was used as a polymeric binder. A light stabilizer of basic hindered amine (HALS) was used as a UV absorber. Silica was used as a filler and UV blocking agent. The coating was applied to polished 6063 aluminum substrates and KBr glass by pneumatic spraying. The chemical transformations in the coating composition were studied using infrared spectrometry. The carbonyl index was used to characterize the degree of polymer degradation. The characterization of chemical transformations on the surface was carried out by measuring the wetting angle Findings. The work shows that nanosized particles at a content of 30 wt. % accelerate the oxidation of the base polymer. At the same time, the content of nanoparticles of 30-50 wt. % slows down the loss of mass and thickness of the coating on the substrate by 2,5-3 times. It has been shown that films based on pure styrenebutyl methacrylate with an initial water wetting angle of 88° during an hour of exposure significantly increase hydrophilicity: the wetting angle decreases to 40°. Originality. As a result of the work, the degree of influence of silica nanoparticles on the physical and chemical properties of the coating in the system film-forming agent - inorganic filler with the addition of a UV stabilizer was determined. Practical value. The revealed regularities showed that nanosized silica particles affect the photodegradation of thin-layer coatings based on styrene-butyl methacrylate film-forming agent. From the point of view of ensuring the stability of water repellency for systems intended for use in atmospheric conditions, this effect is negative. The issue of increasing stability requires further research. [ABSTRACT FROM AUTHOR]

This work developed a method to enhance the durability of anti‐icing performance of a coating to endure abrasion and UV exposure, through grafting functional polydimethylsiloxane (PDMS) to TiO2 particles and further reacting with polysilazane (PSZ) pre‐polymer. This method remarkably improved the anti‐icing properties of PSZ‐based coatings evaluated by freezing delay time and ice removal shear strength. After either surface abrasion for 50 cycles or UV exposure for 100 h, the modified coatings exhibited ice shear strength increase by only 10.44 and 6.44 kPa respectively, significantly lower comparing to that of the coatings containing 30% TiO2 with no PDMS modification (29.69 and 11.88 kPa, respectively). Such strengthened durability of anti‐icing performance is attributed to the PDMS molecules bridging PSZ rigid segments and TiO2 compositions, which formed a hydrophobic cross‐linking network structure. The durable anti‐icing technique developed herein shall appeal to many outdoor applications of facilities and infrastructures. [ABSTRACT FROM AUTHOR]

The microorganisms that thrive in Antarctica, one of the coldest environments on the planet, have developed diverse adaptation mechanisms to survive in these extreme conditions. Through functional metagenomics, in this work, 29 new genes related to cold tolerance have been isolated and characterized from metagenomic libraries of microorganisms from the rhizosphere of two Antarctic plants. Both libraries were hosted in two cold-sensitive strains of Escherichia coli: DH10B ΔcsdA and DH10B ΔcsdA Δrnr. The csdA gene encodes a DEAD-box RNA helicase and rnr gene encodes an exoribonuclease, both essential for cold-adaptation. Cold-tolerance tests have been carried out in solid and liquid media at 15°C. Among the cold-tolerance genes identified, 12 encode hypothetical and unknown proteins, and 17 encode a wide variety of different proteins previously related to other well-characterized ones involved in metabolism reactions, transport and membrane processes, or genetic information processes. Most of them have been connected to coldtolerance mechanisms. Interestingly, 13 genes had no homologs in E. coli, thus potentially providing entirely new adaptation strategies for this bacterium. Moreover, ten genes also conferred resistance to UV-B radiation, another extreme condition in Antarctica. [ABSTRACT FROM AUTHOR]

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The microorganisms that thrive in Antarctica, one of the coldest environments on the planet, have developed diverse adaptation mechanisms to survive in these extreme conditions. Through functional metagenomics, in this work, 29 new genes related to cold tolerance have been isolated and characterized from metagenomic libraries of microorganisms from the rhizosphere of two Antarctic plants. Both libraries were hosted in two cold-sensitive strains of Escherichia coli: DH10B ΔcsdA and DH10B ΔcsdA Δrnr. The csdA gene encodes a DEAD-box RNA helicase and rnr gene encodes an exoribonuclease, both essential for cold-adaptation. Cold-tolerance tests have been carried out in solid and liquid media at 15°C. Among the cold-tolerance genes identified, 12 encode hypothetical and unknown proteins, and 17 encode a wide variety of different proteins previously related to other well-characterized ones involved in metabolism reactions, transport and membrane processes, or genetic information processes. Most of them have been connected to cold-tolerance mechanisms. Interestingly, 13 genes had no homologs in E. coli, thus potentially providing entirely new adaptation strategies for this bacterium. Moreover, ten genes also conferred resistance to UV-B radiation, another extreme condition in Antarctica.

To endow silk with multifunctionality and expand its application fields, the silk fabric was treated with protocatechualdehyde to prepare a novel silk fabric with Schiff base structure (CAT@Silk). Then, CAT@Silk was immersed in iron (III) solution to chelate Fe3+ to obtain flame retardant, antibacterial and UV-resistant silk fabric (CAT@Fe@Silk). Compared with the limiting oxygen index (LOI) value of the original silk, the CAT@Fe@Silk increased from 23.3 % to 35.1 %, and remained 32.4 % even after 20 laundering cycles (LCs), indicating excellent flame retardant durability. The UV protection coefficient of CAT@Fe@Silk was 67.74, which was higher than that of the original sample (21.02). In addition, CAT@Fe@Silk had good antibacterial effects against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). This work constructed a dynamic cross-linking network that mimicked the adhesion of mussels generating from the complexation of catechol groups and Fe3+ ions (catechol-Fe3+), which not only endowed silk fabric with good flame retardancy, but also with UV resistance and antibacterial properties, demonstrating good potential application. [Display omitted] • Modified silk was obtained by a simple impregnation and baking method. • Modified silk had good flame retardancy with an LOI value of 35.1 %. • UV protection coefficient of modified silk was 67.74, showing good UV resistance. • Modified silk had good antibacterial activity for E. coli and S. aureus. • The process was eco-friendly and suitable for large-scale preparation. [ABSTRACT FROM AUTHOR]

Poly (vinyl alcohol) (PVA), as an excellent degradable plastic feedstock, is limited by its diminishing stability in wet environment, low strength, thermal instability and nonopaque properties. In response to these concerns, a PVA/demethylated lignin-based supramolecular plastic (DPVA-HA-Fe-5) was designed and produced from PVA, demethylated lignin (DL), humic acid (HA) and Fe3+ ions via a simple casting method. As compared with pure PVA plastic, the tensile strength of DPVA-HA-Fe-5 were increased by 411 % to 410.61 MPa, and the breaking strain was increased by 149 % to 239.47 %. Notably, the hydrophobicity of DPVA-HA-Fe-5 was also significantly improved. Although in highly humid environment (stored in RH = 100 % for 10 days) or in alkaline organic solvent (stored in pyridine for 3 h), DPVA-HA-Fe-5 also showed excellent mechanical strengths of 302.9 and 222.99 MPa, respectively, which are equivalent or even superior to the most of commercial petroleum-based plastics. Moreover, the prepared plastics showed an outstanding UV resistance and shading performance, and about 98.3 % protection against ultraviolet radiation B rays and 90.7 % protection against visible light were obtained. In short, the introduction of lignin to improve the performance of PVA-based plastic is a feasible method, and it could facilitate the development of high-value utilization of lignin. [Display omitted] • The tensile strength and breaking strain of DPVA-HA-Fe-5 are high up to 410.61 MPa and 239.47 %, respectively. • The tensile strength of DPVA-HA-Fe-5 can retain 302.9 MPa after storing in highly humid environment for 10 days. • The tensile strength of DPVA-HA-Fe-5 can retain 222.99 MPa after immersing in pyridine for 3 h. • DPVA-HA-Fe-5 could be completely degraded by simply buried in soil in 4 months. • DPVA-HA-Fe-5 has excellent UV resistant property and outstanding shading performance. [ABSTRACT FROM AUTHOR]

Antarctica is an untapped reservoir of bacterial communities, which are able to adapt to a huge variety of strategies to cope with extreme conditions and, therefore, are capable of producing potentially valuable compounds for biotechnological applications. In this study, 31 UV-resistant bacteria collected from different Antarctic aquatic environments (surface sea waters/ice and shallow lake sediments) were isolated by UV-C assay and subsequently identified. A phylogenetic analysis based on 16S rRNA gene sequence similarities showed that the isolates were affiliated with Proteobacteria, Actinobacteria and Firmicutes phyla, and they were clustered into 15 bacterial genera, 5 of which were Gram negative (Brevundimonas, Qipengyuania, Sphingorhabdus, Sphingobium, and Psychrobacter) and 10 of which were Gram positive (Staphylococcus, Bacillus, Mesobacillus, Kocuria, Gordonia, Rhodococcus, Micrococcus, Arthrobacter, Agrococcus, and Salinibacterium). Strains belonging to Proteobacteria and Actinobacteria phyla were the most abundant species in all environments. The genus Psychrobacter was dominant in all collection sites, whereas bacteria belonging to Actinobacteria appeared to be the most diverse and rich in terms of species among the investigated sites. Many of these isolates (20 of 31 isolates) were pigmented. Bacterial pigments, which are generally carotenoid-type compounds, are often involved in the protection of cells against the negative effects of UV radiation. For this reason, these pigments may help bacteria to successfully tolerate Antarctic extreme conditions of low temperature and harmful levels of UV radiation.

Perovskite solar cells have demonstrated exceptional photovoltaic performance, but stability remains a challenge due to insufficient interfaces. In this work, a UV-resistance ferrocene derivative, 1,1′-bis (diphenylphosphine) ferrocene (DPPF), is introduced between the electron transport layer and the perovskite, reducing defect density by interaction with undercoordinated Pb2+, suppressing non-radiative recombination of charge carriers, and enhancing electron extraction. Desirable interfacial properties and homogeneous perovskite grains are formed, resulting in a champion power conversion efficiency (PCE) of 20.82 % and a significantly improved fill factor of 83.57 %. Moreover, DPPF can optimize the interfaces, provide a brand-new morphology with exceptional air durability, cover the active layer to restrain water and oxygen intrusion, and suppress metal electrode corrosion. Resultant devices without encapsulation have remained above 80 % of their initial PCE for 1400 h under 25 °C air and 50–60 % relative humidity conditions. • UV-resistance ferrocene derivative as defect passivator applied in perovskite solar cells. • The air-stability of the modified PSCs was remained 80 % above 1400 h. • DPPF modification increased fill factor from 78.93 % to 83.57 %. [ABSTRACT FROM AUTHOR]

Exterior claddings are used for architectural purposes primarily for practical and esthetic reasons. Panels are subjected to a variety of impacts, including chemical, and ultraviolet radiation, and are intended to survive them. In this study, the color, gloss, chemical and UV resistance, impact resistance, and surface tension of glass-ceramic (GC) coated steel panels and other products on the market, such as conventional ceramic wall tiles, glass, and aluminum panels, are compared. Three different types of GC powders were prepared: opaque, semi-transparent, and transparent. Each GC powder was applied to a pre-coated steel substrate. Chemical resistance was excellent in all samples, however, only the GC-coated steel panels and the aluminum panels satisfied the impact resistance criteria. A UV test was performed to ensure that surface characteristics such as gloss, color, and surface tension were stable in the presence of UV light. The aluminum gives alerts the most color shift (∆E ≈ 1.2), whereas the GC-coated steel panels showed just ∆E ≈ 0.2. The gloss values of the samples did not change significantly much. Furthermore, when compared to the other products, GC-coated samples had the lowest weight and the greatest performance.

Superhydrophobic textiles are important superhydrophobic materials because of their low cost and high demand. In this work, low surface energy substance, dodecyltrimethoxysilane (DTM), was used to modify the hydrolyzed tetrabutyl titanate (Ti(OH)4) to obtain DTM@Ti(OH)4 particles and realize the surface organic modification of Ti(OH)4 particles. Then, functional cotton fabric was prepared by loading DTM@Ti(OH)4 particles onto the fabric based on the adhesion of natural polyphenols. The static contact angle of finished cotton fabric was up to 169.9°, the rolling contact angle was less than 8°, and the UPF value was generally greater than 70. Due to the excellent adhesion of polyphenols, the superhydrophobic cotton fabric showed great stability and durability under harsh environmental conditions. By various treatments, the water contact angles (CA) of the finished fabrics can still be greater than 155° and the UPF value was still greater than 50. The preparation process is simple, efficient and low-cost, which is suitable for large-scale industrial production. Encouragingly, this modification method is universal and can be applied to other kinds of fabrics. It has broad application prospects in outdoor textiles, oil and water separation, metal corrosion prevention and other fields. [ABSTRACT FROM AUTHOR]

• Surface manipulation of dyed silk fabrics with either silver or palladium. • Ag and Pd acted as mordant and functionalizing agents of dyed fabrics. • In absence of mordant, color fastness were graded as very good-outstanding. • In absence of mordant, dyed sample immobilized with Pd exhibited UPF of 33.1. • Microbial reduction % was in the range of excellence (94.13–98.27 %). Nowadays, manufacturing of technical textiles has acquired great interest, as many attempts were performed for acquiring different textile materials new functions. In the demonstrated contribution, surface manipulation of dyed silk fabrics was performed with either silver or palladium as substituents of mordant and to acquire the prepared samples UV-resistance and biocidal actions. The current study reveals that, surface manipulated dyed samples were exhibited with the best color strength, color fastness, biocidal performance and UV-resistance. Color fastness (washing, perspiration and light fastness) of the surface manipulated dyed samples was rated as very good-outstanding. Excellent UV-blocking potency (UPF, 33.1 and UVB blocking percent 97.3 %) was achieved for the dyed silk that was prepared with palladium. Biocidal performance against E. coli, S. aureus and Candida albicans was examined for surface manipulated dyed samples, and the reduction % was also graded to be in range of very good to excellent (94.13–98.27 %). [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • PDA, PEI and HCCP constitute a mussel-inspired biomimetic multifunctional coating. • The functional coating endows lyocell fabrics with flame retardancy and UV resistance. • The mussel-inspired biomimetic coating improved the mechanical properties of lyocell fibers. • The coating process is simple and efficient, suitable for large-scale preparation. Inspired by mussel adhesion proteins, the in-situ self-polymerization of dopamine (DA) was performed to generate a secondary reaction platform on the surface of lyocell fabrics, then a novel flame retardant and UV-resistant functionalized coating was constructed by introducing hexachlorocyclotriphosphazene (HCCP) and polyethyleneimine (PEI). Thermogravimetric (TG) and combustion test results showed that the introduced P/N elements had significant positive effects on char formation ability and flame retardancy. In particular, the peak heat release rate (PHRR) and total heat release (THR) of the treated sample decreased by 89.55% and 89.51%, while the limiting oxygen index (LOI) value of the treated samples maintained above 33.2% after 20 laundering cycles (LCs). In addition, the ultraviolet protection factor (UPF) values of the treated samples were significantly increased from 9.31 of the control sample to 666.04, and the tensile strength and elongation at break were correspondingly increased by 6.51% and 9.57%. This work provided a general and advanced strategy for the preparation of high-performance textiles with integrated flame retardancy, UV-resistance and mechanical enhancement. [ABSTRACT FROM AUTHOR]

Through ring-opening polymerization of L-lactide, aloin, a natural compound, was bonded to the polymeric chains and the molecular structures of obtained PLA-An were characterized by FT-IR and NMR. Measurements on the UV-Vis absorption and fluorescence emission spectroscopy show that PLA-An has a characteristic absorption of aloin and a large Stokes shift at the state of solution in the PL, being capable of absorbing UV light and dissipating some of UV energy. Additionally, due to chemical bonds, aloin groups aren't easy to be extracted by solvent, which allows aloin to play the role of ultraviolet absorption for a long time. [ABSTRACT FROM AUTHOR]

Little is known about final spores components when bacteria undergo sporulation under different nutrient conditions. Different degrees of resistance and germination rates were observed in the three types of spores of Lysinibacillus boronitolerans YS11 (SD, Spores formed in Difco sporulation medium™; SC and SF, Spores formed in an agricultural byproduct medium with 10 mM CaCl2 and with 10 mM FeSO4, respectively). Stronger UV resistance was recorded for SF with 1.8–2.3-fold greater survival than SC and SD under UV treatment. The three spore types showed similar heat resistances at 80°C, but survival rates of SC and SD were much higher (∼1,000 times) than those of SF at 90°C. However, germination capacity of SF was 20% higher than those of SD and SC on Luria-Bertani agar plates for 24 h. SF germinated more rapidly in a liquid medium with high NaCl concentrations than SC and SD, but became slower under alkaline conditions. Raman spectroscopy was used to analyze the heterogeneities in the three types of vegetative cells and their spores under different nutritional conditions. Exponentially grown-each vegetative cells had different overall Raman peak values. Raman peaks of SC, SD, and SF also showed differences in adenine and amide III compositions and nucleic acid contents. Our data along with Raman spectroscopy provided the evidence that spores formed under under different growth conditions possess very different cellular components, which affected their survival and germination rates. [ABSTRACT FROM AUTHOR]

Deterioration in mechanical performances and aging resistance due to the introduction of flame retardants is a major obstacle for bio-based fire-safety polypropylene (PP). Herein, we reported a kind of functionalized lignin nanoparticles assembled with MXene (MX@LNP), and applied it to construct the flame-retardant PP composites (PP-MA) with superior fire safety, excellent mechanical performance, electromagnetic shielding effects and aging resistance. Specifically, the PP-MA doped with only 18 wt% flame-retardant additives (PP-MA18) achieved the UL-94 V-0 rating. In comparison to pure PP, PP-MA18 presented a greatly decreased peak of heat release rate (pHRR), total heat rate (THR), and peak smoke production rate (pSPR) by 79.7 %, 69.0 % and 75.8 %, respectively, and satisfactory decrease in total flammable and toxic volatiles evolved. The formed fine solid microstructure of carbon residuals effectively promoted the compactness of char layers. More importantly, the nano-effect and the strong interface interaction between the complexed MX@LNP and PP enhanced the tensile strength (45.78 MPa) and elongation at break (725.95 %) of PP-MA. Additionally, the significant ultraviolet absorption and electromagnetic wave dissipation performance of MXene and lignin enabled excellent aging resistance and electromagnetic shielding effects of PP-MA compared with PP. This achieved MX@LNP afforded a novel approach for developing flame retardant materials with excellent application performance. [Display omitted] [ABSTRACT FROM AUTHOR]

In order to endow polyvinyl alcohol (PVA) film with the functionalities of highly-effective flame retardancy and optical properties, the strategy of doping phosphorus into carbon quantum dots (CQDs) and then using the P-containing CQDs as flame retardant is worthy investigating. In this work, m -phenylenediamine (MPD), 2-carboxyl ethyl(phenyl)phosphinic acid (HPP) and phytanic acid (PA) were used as carbon source and phosphorus sources to synthesize three kinds of CQDs, which were named as MPD-CQDs, MPD-HPP-CQDs and MPD-PA-CQDs respectively. Subsequently, the CQDs-PVA composite films were prepared by blending CQDs with PVA solution through casting process, the flame retardancy and UV shielding properties of the PVA-CQDs composite films were tested by kinds of techniques such as vertical burning tests (UL-94), limited oxygen index (LOI), UV–visible spectroscopy and so on. In addition, the residual char structure of the composite films was investigated by SEM and EDS. The results showed that compared with phosphorus-free MPD-CQDs, the two P-containing CQDs, both MPD-HPP-CQDs and MPD-PA CQDs, produced better flame-retardant effect on the PVA film. As the percentage of phosphorus increased, the flame retardancy of CQDs-PVA composite film greatly enhanced. When 15% MPD-HPP-CQDs and 15% MPD-PA-CQDs were added to PVA, the LOI value of MPD-HPP-CQDs-PVA and MPD-PA-CQDs-PVA was 27.8% and 31.5% respectively, meanwhile, the UL-94 rating reached VTM-1 and VTM-0, respectively. Due to the intact layer of P-containing condensed phase, the gas diffusion and oxygen transportation were hindered, which slowed down the combustion and promoted the further carbonation. In addition, both MPD-HPP-CQDs-PVA and MPD-PA-CQDs-PVA composite films exhibited good UV shielding properties without affecting the transparency of PVA itself. [Display omitted] • Two phosphorus-doped carbon quantum dots were designed to explore the flame retardant effect on polyvinyl alcohol film. • PVA-CQDs composited film exhibited highly-effective flame retardancy and good optical properties at low addition of CQDs. • The flame retardant mechanism of MPD-HPP-CQDs-PVA and MPD-PA-CQDs-PVA films was investigated. • The prepared film exhibited excellent UV shielding properties without affecting the transparency. [ABSTRACT FROM AUTHOR]

Regions with extreme environmental conditions can be considered as a system with unique biodiversity and potential. The aim was to determine resistance range to UVirradiation, temperature and concentration of NaCl, the glycosidase and proteolytic activity of bacteria isolated from terrestrial ecosystems of Antarctica, Ecuador and Israel. Methods. The objects of study were 19 extremе-tolerant bacteria. UV-irradiation of bacteria was performed with a BUF-15 lamp (λ = 254 nm) in the range of 37-1440 J/m². The temperature range of growth was determined at a temperature of 1-42 ºC, halotolerance -- at NaCl concentration of 1-100 g/l. Enzymes activities were studied in the culture supernatant. To determine glycosidase activities, p-nitrophenyl substrates, galactomannan guar and soluble starch were used. Casein and elastin were used as substrates for the determination of proteolytic activity. Results. Antarctic pigmented microorganisms showed a higher resistance to UV than non-pigmented. Cultures from highland biotopes and saline soils were resistant to UV-doses of 400-1440 J/m². Investigated strains mainly belonged to psychotolerant and moderately halophilic bacteria. Most of the strains showed α-amylase and/or β-mannanase activity. Two strains, 3271 and 3456, exhibited simultaneously four and five glycosidase activities respectively. Caseinolytic activity was observed in 17 cultures, elastase -- in one. Conclusions. Ecophysiological characteristics of the studied cultures reflect their adaptation to extreme environmental conditions. Both pigmented and non-pigmented microorganisms were resistant to UV-radiation, most of them are psychrotolerant moderate halophiles with α-amylase, β-mannanase, caseinolytic and elastase activity. [ABSTRACT FROM AUTHOR]

Abstract The pursuit of improving the performance of rigid-rod polymeric fibers using a new inorganic nano-materials and efficient methods is very attractive topic. The combination of the unusual properties of both materials could definitely produce an outstanding final product. Herein, we proposed a simple grafting method of a graphene-like titanium carbides Ti 3 C 2 (OH) 2 nanosheets (MXene) onto PIPD surface via covalent bond by using (3-Aminopropyl) triethoxysilane (APTES) as a bridging agent. The surface morphology and element compositions of PIPD fiber before and after grafting were characterized, and the effect of such treatment on the mechanical properties was also evaluated. The IFSS of the PIPD-Ti 3 C 2 (OH) 2 was highly increased by 61.54% because of the significant improvement the fiber/epoxy interaction and surface wettability. Though the tensile strength (TS) was slightly decreased by only 5%. Furthermore, the experiment results showed a great enhancement of UV and hydrothermal aging resistance of the grafted fibers comparing with untreated ones by 33% and 25% respectively. Highlights • Improving interfacial properties of PIPD fiber by grafting 2D transition metal carbides MXene. • Prevent the PIPD fiber degradation after long term UV exposure using Ti 3 C 2 (OH) 2 nanosheets. • Provide an interfacial protection for PIPD fiber against harsh environmental conditions. • Propose surface modification method using less damage treatment conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • GQDs was tailor-synthesized as multifunctional fillers for biosynthesized PHAs. • Condensed crystals and robust performance were generated simultaneously. • UV-resistance (90%), antibacterial (99.99%) transparency (80%), pH-responsive. • The PHAs nanocomposites could be ideal for green packaging. Biosynthesized polyhydroxyalkanoates (PHAs) offer several compelling advantages, including biodegradability, biocompatibility, and suitability for use in environmentally friendly packaging materials. However, poor crystallization ability and lack of functionality (e.g., UV-resistance and antibacterial properties) significantly restrict the practical applications of PHAs. In this study, graphene quantum dots (GQDs) containing with rich amino groups, carboxy groups and conjugate structure were tailor-made as multifunctional nanofillers to prepare PHAs/GQDs composites. The GQDs not only exhibited excellent dispersion within the PHAs matrix at the nanoscale but also act as nucleating agents to dramatically increase the nucleation density of PHAs. Remarkably, the incorporation of just 0.5 wt% GQDs led to outstanding antibacterial performance (99.99%), UV resistance (90.50%), transparency (>80%) and mechanical properties in the PHAs composite. ​Moreover, these PHAs composites displayed strong fluorescence stability and demonstrated sensitivity to pH variations. Building upon these findings, we propose a novel concept for a wearable device capable of intelligently detecting changes in sweat pH during human exercise. This work presents a straightforward and effective method for preparing multifunctional GQDs, thereby expanding the potential applications of PHAs in the realm of green packaging and intelligent sensing. [ABSTRACT FROM AUTHOR]

Constructing novel surface structure to overcome two bottlenecks (low surface activity and poor resistance to UV) of aramid fiber (KF) is a meaningful topic. Herein, a new hybridized UV absorber (PDA@tBN@CeO 2 ) with strong UV absorption, low catalytic activity and high heat resistance was synthesized by forming nano turbostratic boron nitride (tBN) and polydopamine (PDA) shells on CeO 2 core, successively. The double shell-core structure not only significantly reduces the photocatalytic activity of CeO 2 , but also obviously improves the UV-blocking effect of CeO 2 and provides active groups for chemical grafting with KF. On this basis, three modified KFs (T-KF1, T-KF2, T-KF3) were fabricated by constructing unique surface structure with different loading of PDA@tBN@CeO 2 through chemical bonds, guaranteeing the good interface between KF and PDA@tBN@CeO 2 . The effects of PDA@tBN@CeO 2 concentration on structure and overall performances (surface activity, UV resistance, thermal and mechanical properties) of T-KF fibers were investigated. All T-KFs have greatly improved surface activity and UV-resistance, the improvement degree is dependent on the loading of PDA@tBN@CeO 2 . For T-KF2 with 1 wt% of PDA@tBN@CeO 2 , its initial decomposition temperature and the value after 168 h-UV irradiation are 49 °C and 90 °C higher than those of original KF, respectively; moreover, tensile strength and energy to break of T-KF2 are severally 1.14 and 1.21 times of those of original KF, the simultaneously improved degrees are the best values among modified KFs reported so far. In addition, T-KFs show outstanding retentions of tensile performances after 168 h UV irradiation, especially, the retention of energy to break of T-KF2 is 1.62 times of that of KF. The excellent integrated performances of T-KF are proved to be attributed to the unique structure of PDA@tBN@CeO 2 as well as the interaction between PDA@tBN@CeO 2 and KF. [ABSTRACT FROM AUTHOR]

Developing multifunctional biodegradable PLA with ignition delay, high efficient fire retardancy, and UV resistance properties is a challenging task owing to its high flammability, and mutually exclusive phenomenon between the latter two properties. In this work, we report a superior efficient synergistic action combining piperazine pyrophosphate (PAPP) and a Co based metal-organic framework (ZIF-67). Results illustrated that with merely 0.06 wt% ZIF-67, intumescent PLA containing 4.96 wt% PAPP reached UL-94 V0 rating. The PLA/4.9PAPP/0.1MOF sample possessed a limiting oxygen index (LOI) value at 33 %, exhibited a 28 % reduction in peak heat release rate (pHRR) and a 67 % increase in fire propagation index (FPI). Moreover, the presence MOF delayed the ignition time of PLA by 12 s due to the highly porous structure of MOF and its chemical heat-sink performance. Insightful reaction to fire mechanism in the condensed phase via TG-FTIR and Raman revealed that a crack free protective intumescent char layer with higher graphitization degree was formed, which effectively enhanced the barrier effect and minimize the heat and fuel transfer. In addition, the UV resistance of PLA composites is enhanced, remaining at and below 5 % transmittance in the UVA and UVB areas. This work provides a green production way of multifunctional degradable materials and broadens their application fields. Synopsis: By utilising a high-efficiency fire retardant, this work simultaneously prepared fire retardant, ignition delayed and UV resistant PLA composites. It expands the fields of application for multifunctional degradable materials while offering a green method of production. [Display omitted] [ABSTRACT FROM AUTHOR]

Numerous researches were interestingly considered with investigation of unique strategies for industrialization of efficacious textiles to find wide-scaled applicability in different purposes. The demonstrated approach represents unique strategy for manufacturing of fluorescent/UV-resistant/microbicide cotton via exploitation of silver nanoparticles (AgNPs), carbon quantum dots (CQDs) and silver nanoparticles-doped carbon quantum dots (AgNPs-CQDs) to be applicable as efficacious textiles. Whereas, both CQDs and AgNPs were formerly clustered from alginate biopolymer. Topographical features and particle size of AgNPs (7.5 ± 2.6 nm), CQDs (4.9 ± 1.7 nm) & AgNPs-CQDs (4.0 ± 1.4 nm) were investigated via microscopic images and Zetasizer data. Spectral mapping data for the photoluminescent emission showed that, AgNPs, CQDs & AgNPs-CQDs were exhibited with two intense peaks at 370 nm & 490 nm. Cotton fabrics were sequentially treated with CQDs, Ag-CQDs & AgNPs-CQDs to prepare CQDs@Cotton, Ag-CQDs@Cotton and AgNPs-CQDs@Cotton, respectively. Thermal stability, colorimetric properties/color strength, UV-resistance and antimicrobial potentiality were studied for all the prepared samples. AgNPs-CQDs@Cotton exhibited excellent UV-resistance (UPF, 43.4) and antimicrobial activity, whereas the diameter of inhibition zone was estimated for its affinity against S. aureus , E. coli and C. albicans , to be 14 mm, 18 mm and 16 mm, respectively. [Display omitted] • Fluorescent/UV-resistant/microbicidal effecieous textile via AgNPs doped-CQDs. • CQDs and AgNPs were formerly clustered from alginate biopolymer. • AgNPs, CQDs & AgNPs-CQDs exhibited size of 7.5, 4.9 & 4.0 nm, respectively. • AgNPs-CQDs@cotton was obviously observed with the highest thermal stability. • AgNPs-CQDs@Cotton exhibited excellent UV-resistance and antimicrobial performance. [ABSTRACT FROM AUTHOR]

On account of environment concerns and the gradually depletion of fossil resources, a hyperbranched waterborne polyurethane (HWPU) serving for sizing agent of carbon fibers (CF) was designed based on bio-based materials. Hyperbranched chain extender named CAG was synthesized by citric acid (CA) and glycerol as HWPU precursor. Tartaric acid (TA) was coordinated with nano titanium dioxide (TiO 2) through two –COOH groups, which was introduced to HWPU as the chain extender, leading to a significant improvement in ultraviolet (UV)-resistant of the sizing agent. The interfacial performance promotion of CF reinforced nylon 6 (CF/PA6) composites contributed by the HWPU sizing agent were systematically investigated. In contrast to the untreated CF composites, the mechanical performance arrived the best improvement after sizing by concentration of 1.5 wt%, which exhibited a dramatic promote of 44.9% in interlaminar shear strength (ILSS), 58.7% in interfacial shear strength (IFSS) and 43.3% in flexural strength. Extraordinary, the treated CF composites remained over 98% of mechanical performance after a week of unremitting ultraviolet irradiation, signifying the outstanding UV-resistance of the TiO 2 modified HWPU sizing agent. The reinforcement mechanism introduced by HWPU sizing agent. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Multifunctional vanillin-based porphyrin (VPR) was designed and synthesized. • PLA/VPR biocomposites exhibited highly enhanced toughness. • PLA/VPR biocomposites showed excellent UV-resistance properties. • PLA/VPR biocomposites presented great self-extinguishing performance. To achieve high-performance polylactic acid (PLA) composites, the exploitation of multifunctional biomass additives derived from renewable resources are highly demanded. Herein, a vanillin-based porphyrin (VPR) was designed and synthesized to impart PLA with enhanced mechanical, anti-UV, and flame retardant properties. Multiple intermolecular interactions between VPR and PLA enabled significant toughening of the PLA/VPR biocomposites compared to PLA itself. The elongation at break and impact strength for PLA/3VPR were improved by 88.2 % and 104.2 %, respectively, without influence on their tensile strength. Furthermore, the PLA/VPR biocomposites exhibited improved anti-UV performance with only 1.5 % and 8.6 % decrease of the strength and elongation at break respectively after UV aging. More importantly, incorporation of only 3 wt% VPR loading within the PLA/3VPR composite allowed for excellent self-extinguishing with a UL-94 V-0 level, greatly improving the versatility of PLA composites. We envision that such bio-based PLA/VPR materials with multifunctional features will extensively broaden the usable range of PLA composites. [ABSTRACT FROM AUTHOR]

A durable and self-healing superhydrophobic polyvinylidene fluoride (PVDF)/polyester-modified silicone resin (PMSR)/microspheric Na 2 CO 3 @SiO 2 coating with WCA of 158 ± 1.5° and low SA of 4 ± 0.5° has been successfully prepared via sol-gel and spraying technique. After 24 h hydrolysis of tetraethylorthosilicate (TEOS), microspheric Na 2 CO 3 @SiO 2 particles with extremely large storage spaces were obtained as reservoirs for the healing agent of POTS. The superhydrophobicity of the prepared coating can be recovered after 10 rubbing/healing test cycles, indicating the excellent self-healing ability. Simultaneously, the prepared coating also possesses gas compensation capability in acidic condition, which can extend superhydrophobic duration by 400%. The gas compensation capability can be mainly attributed to the bubbles generated from the reaction between acid and porous Na 2 CO 3 , hindering water wetting the surface. Moreover, the prepared coating can withstand 4217 friction cycles without obvious surface damage, which is approximately 6 times higher than that of pure PVDF coating. This is mainly due to the combined action of the high adhesion of PMSR, the self-lubrication of PVDF and the surface hierarchical nano/micro wrinkles. The prepared coating also shows prominent superhydrophobic stability under the conditions of acid/alkaline solution (pH = 1–14) or strong UV exposure (14 days). It is believed that this durable and self-healing superhydrophobic coating is anticipated to open a new avenue to enlarge the application range of superhydrophobic coatings. [ABSTRACT FROM AUTHOR]

Adding titanium dioxide (TiO 2 ) into Polylactide (PLA) matrix is an efficient way to improve the UV-resistance of PLA for outdoor applications. In this work, soft poly(ester)urethane elastomer was used to tailor the dispersion and distribution of TiO 2 nanoparticles and improve the toughness of PLA as well. It was observed that TiO 2 nanoparticels are selectively located at the interface between PU dispersed phase and PLA matrix to form a so called soft core-rigid shell structure. Interestingly, the addition of PU gives a significant rise to not only toughness, but also UV-resistance of PLA/TiO 2 composites. According to Fourier transform infrared spectroscopy (FTIR), the anhydride as the main photoproducts was confirmed for all the prepared samples, including PLA, PLA/PU blends, PLA/TiO 2 and (PLA/TiO 2 )PU nanocomposites, which indicates that the addition of PU or/and TiO 2 does not alter the photooxidation chemical mechanism of PLA. The enhancement of anti -UV performance is mainly ascribed to good UV-absorption ability of PU and TiO 2 nanoparticels. [ABSTRACT FROM AUTHOR]

The results are presented of the detection of volatile organic compounds, that is, degradation products of polymers, under the influence of UV radiation decomposition of polymer films from oxobiodegradable polyethylene on samples using an 'electronic-nose' gas analyzer based on other selective piezosensors. The polymer films were obtained using different prooxidants: d2w, carboxylate, and iron stearate. The dependence of the composition of the films of the compounds was related to the treatment time, the power of the UV radiation, and the nature of the additives. [ABSTRACT FROM AUTHOR]

Using facile strategy to prepare UV resistant aramid fibers (KFs) with high surface activity, thermal and mechanical properties is the most important and urgent issue of sustainably developing high performance organic fibers. Herein, a novel two-step strategy has been built to prepare new KF (KF-PDA-GO) with remarkably improved integrated performances by forming polydopamine (PDA) and graphene oxide (GO) bi-layer coatings on the surfaces of KFs. Orthogonal tests based on three factors and three levels were designed and carried out to systematically study the influences of dopamine (DA) concentration, GO concentration and reaction temperature on the structure and performances of KF-PDA-GO fibers. Results show that the reaction temperature is the decisive factor for both surface active and UV-resistance. All KF-PDA-GO fibers not only have greatly improved surface activity and UV resistance, overcoming the two intractable disadvantages of KFs, but also show outstanding thermal resistance and higher tensile properties including tensile strength, modulus, elongation and break energy. For the new fiber (KF-PDA-GO3) prepared with the optimum conditions, its surface free energy increases 54%, meanwhile the retention of tensile strength after 168 h-UV irradiation is as high as 93.4%, almost the best value among the latest modified KF fibers reported. Different failure modes are found between original and modified KF fibers through intensively discussing the morphological and chemical structures of fibers. This investigation provides a novel and facile method to develop new KF fibers with higher integrated performances, especially outstanding surface activity, UV resistance, thermal and mechanical properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • The hydrophilic ZGST coating exhibits sustainable anti-fogging and anti-freezing performance. • The double-layer structure of ZGST coating provides excellent UV-shielding ability. • The ZGST coating exhibits good outdoor stability for anti-fogging greenhouse film. Special wettability endows surface anti-fogging performance on transparent substrates by promoting filmwise condensation via hydrophilic materials or preventing water adhesion via hydrophobic materials. However, the harsh environments associated with low temperature and mechanical loads restrict their anti-fogging persistence. In this work, a hydrophilic coating with long-lasting anti-fogging, anti-freezing, and anti-aging properties was rationally prepared by constructing a double-layer structure. The bottom layer (T coating) adopts a titanium dioxide coating obtained by hydrolysis of tetrabutyl titanate, which can act as a UV absorber and improve the UV-shielding property of the coating. The top layer (ZGS coating) is constructed of a cross-linked network structure with zein, gelatin, glucose and silica for anti-freezing and anti-fogging properties. The resulting coating (ZGST) can maintain excellent anti-fogging performance after placing in a hot fog environment (100℃) for 1 h, 300 cycles abrasion, 70 tape-peeling, 120 min ultrasonication and extended service time (261 days so for). One application of greenhouse films with anti-fogging performance was demonstrated, which can improve the status quo of agricultural film and has important significance for the field of agricultural development. It is anticipated that this work may offer valuable guidance for the preparation of anti-fogging, anti-freezing and UV resistant optical materials, which allows potential applications in vehicles, medical, agricultural or vision systems under extreme environments. [ABSTRACT FROM AUTHOR]

Ultraviolet radiation can damage biomolecules, with detrimental or even lethal effects for life. Even though lower wavelengths are filtered by the ozone layer, a significant amount of harmful UV-B and UV-A radiation reach Earth’s surface, particularly in high altitude environments. High-Altitude Andean Lakes (HAAL) are a group of disperse shallow lakes and salterns, located at the Dry Central Andes region in South America at altitudes above 3,000 m. As it is considered one of the highest UV-exposed environments, HAAL microbes constitute model systems to study UV-resistance mechanisms in environmental bacteria at various complexity levels. Herein, we present the genome sequence of Acinetobacter sp. Ver3, a gammaproteobacterium isolated from Lake Verde (4,400 m), together with further experimental evidence supporting the phenomenological observations regarding this bacterium ability to cope with increased UV-induced DNA damage. Comparison with the genomes of other Acinetobacter strains highlighted a number of unique genes, such as a novel cryptochrome. Proteomic profiling of UV-exposed cells identified up-regulated proteins such as a specific cytoplasmic catalase, a putative regulator, and proteins associated to amino acid and protein synthesis. Down-regulated proteins were related to several energy-generating pathways such as glycolysis, beta-oxidation of fatty acids and electronic respiratory chain. To the best of our knowledge, this is the first report on a genome from a polyextremophilic Acinetobacter strain. From the genomic and proteomic data, an UV-resistome was defined, encompassing the genes that would support the outstanding UV-resistance of this strain.

Titanium dioxide nanoparticles (TiO 2 NP) were grown on aramid fiber (AF) by a low-temperature hydrothermal method with the aim to enhance the poor interfacial strength and the UV resistance properties of the fiber material. Prior to the growing process, AF was functionalized to increase the fiber-TiO 2 NP bonding strength. The structure, interface strength, and UV resistance properties of the resulting TiO 2 NP-modified fiber material were investigated. Anatase TiO 2 NP were uniformly grown on the fiber surface while controlling the TiO 2 particle size upon addition of polyethylene glycol (PEG). The growth of TiO 2 NP increased the interaction area and reduced the stress concentration between the fiber and the matrix material. The experimental testing results revealed a significant improvement (by 40–67%) in the interfacial shear strength (IFSS) upon development of the TiO 2 NP interphase while essentially maintaining the basic strength of the fiber material. Unlike other TiO 2 -coating methodologies such as sol-gel and sizing, the herein developed process, leading to complete anatase TiO 2 NP coating, provided the fiber with effective UV-rays protection characteristics while retaining most of the tensile strength (87.1–90.5%) after long UV irradiation exposure (168 h). [ABSTRACT FROM AUTHOR]

The high UV radiation and scarcity of liquid water in desert areas make these regions among the most challenging environments for life. Here we studied the multitolerant microbial communities of deserts in Iran. Three bacterial strains were isolated and identified asMicrobacterium phyllosphaeraeMG3,Kocuria flavaMG5 andExiguobacterium acetylicumMG7. UV resistance and desiccation tolerance in MG7 and MG5 strains were comparable to multiresistantDeinococcus radiodurans. Also, resistance to mitomycin C and hydrogen peroxide in all isolated strains were significant. The strain MG3 showed moderate to poor salt tolerance but strains MG5 and MG7 showed high NaCl tolerance. [ABSTRACT FROM AUTHOR]

Here we report a simple, facile and low-cost approach to the cotton textile with significant properties. After treatment, the cotton textiles exhibit not only an excellent superhydrophobicity with the water contact angle (WCA) of 151.5 o , but also an efficient shielding property against UV with the transmittance under 2.0%. More importantly, this cotton displays an outstanding potency in oil reclaim, which can recycle oil from the waste water with oil stain efficiently. Apparently, our results suggest an innovative material that should find practical and diversified applications, particularly in the field of oil spill cleanup. [ABSTRACT FROM AUTHOR]

In order to avoid the inherent photo-catalysis and aggregation of TiO 2 in PPS, TiO 2 nanoparticles were coated with SiO 2 layers, which were chosen as the UV absorbent to improve the UV stability of polyphenylene sulfide (PPS) fiber. The PPS–TiO 2 @SiO 2 nanocomposites fibers were prepared via melt spinning, and the nanocomposites fibers displayed different crystallization behaviors on variation of the diameters of TiO 2 @SiO 2 nanoparticles, as confirmed by Differential Scanning Calorimetry (DSC). The spinnability, breaking strength and UV-resistance properties of PPS nanocomposites fibers, as measured by homemade melt spinning machine, Xenon-lamp Weather Resistance Test Chamber and Yarn Tensile Tester, manifested the dependence on the diameters. The addition of nanoparticles with the diameter of 25 nm improved the spinnability and the mechanical performance of PPS most, which is attributed to the heterogeneous nucleation effect of nanoparticles. The UV-resistance properties of the PPS nanocomposites were improved by the addition of TiO 2 @SiO 2 nanoparticles. After aging for 180 h, PPS nanocomposites fiber still maintained a high strength. [ABSTRACT FROM AUTHOR]

An ultraviolet (UV) radiation resistant gram-positive bacterium, Dietzia sp. MG4 strain, was isolated from the Sirch Hot Spring (Kerman, Iran), then it was identified on the basis of morphological and biochemical characteristics, and 16S rRNA gene sequencing. The effects of temperature, pH, desiccation, different percentage of NaCl, hydrogen peroxide (HO), mitomycin C (MMC) and high levels of radiation on viability or growth rate of MG4 strain were investigated. Also heavy metal tolerance of MG4 strain was assayed. 16S rDNA sequence of the isolate exhibited 99.69% similarity with Dietzia sp. and this result was confirmed by phylogenetic analysis. Viability of this strain was obtained D according to D index after exposure to 25 J/cm UV radiation dose, and D after desiccation stress (for 28 days) using flow cytometery. The D value for a microorganism is defined as the stress dose necessary to provide 10% survivors. Therefore, this strain showed high resistance to UV-C radiation and moderate resistance to desiccation. Optimal growth of MG4 strain was observed at pH 9, temperature of 30°C and 5% (w/v) NaCl. Isolated Dietzia was resisted up to 3 mM of nickel and 0.2 mM of mercury ions. Also this strain could tolerate 1-4% (v/v) HO and 8 µg/mL of MMC as oxidant agents. To the best of our knowledge, this is the first study on multiple extreme resistant Dietzia sp. MG4 strain. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel hybrid nanoSiO 2 containing fluorinated organic (NS@TOFS) was designed. • NS@TOFS can reduce the water absorption and carbonation of coated mortar. • NS@TOFS modified surface shows less degradation after exposure to UV-rays. • A triple layered structure of NS@TOFS modified surface was found and clarified. In surface treatment technics of cement-based materials, nanoSiO 2 (NS) is effective in refining pore structure while organic water-repelling agents are often used for producing a hydrophobic surface. Due to its advantages of pore refining effect and hydrophobicity, the organic-inorganic hybrid nanoSiO 2 has attracted increasing attention. However, the UV-irradiation can result in photodegradation of organic constituents, leading to deterioration of hydrophobicity. In this study, a novel UV-resistant fluorinated hybrid nanocomposite, NS@TOFS, was synthesized and used for surface treatment on hardened cement-based materials. The water and gas permeability of the treated samples before and after UV-aging were assessed by measuring the water absorption rate, water contact angle and carbonation degree. The experimental results showed that the NS@TOFS treated samples possess enhanced water and gas impermeability after 14 days of exposure to UV rays. A morphological observation of the treated surface revealed that a synergistic effect of organic film and refined pore structure was responsible for the improved surface properties. Findings from this study well demonstrate that the developed fluorinated hybrid nanoSiO 2 holds great promise for enhancing the durability of cement-based materials under UV-irradiations. [ABSTRACT FROM AUTHOR]

[Display omitted] • Zinc porphyrin complex was synthesized via Alder-Longo and complexation. • PS/zinc porphyrin showed outstanding thermal stability and UV-resistance. • PS/zinc porphyrin exhibited improved mechanically strength and toughness. • PS/zinc porphyrin demonstrated enhanced fire safety properties. Polystyrene (PS) is one of the most commonly used general plastics. Nonetheless, PS is greatly limited by its inherent disadvantages such as high flammability, low stability and brittleness. To address these issues, 5,10,15,20-tetrakis(4-bromophenyl) porphyrin (TBPP) and zinc 5,10,15,20-tetrakis(4-bromophenyl) porphyrin (Zn-TBPP) were synthesized as multifunctional additives for fabricating high-performance PS composites. Both TBPP and Zn-TBPP showed high thermal stability and excellent UV-absorption, which significantly enhanced the UV-resistance of PS without sacrificing mechanical property after 100 h UV-aging. The addition of 5 wt% Zn-TBPP led to the remarkable improvement of thermal stability of PS (41 °C and 79 °C increases in the thermal decomposition temperature at 5 wt% mass loss under N 2 and air, respectively). Moreover, contributed from the strong π-π interaction between porphyrins and PS chains, the mechanical properties of PS were enhanced when 5 wt% Zn-TBPP was added into PS (11.1% increase in tensile strength and 96.6% increase in elongation at break). Furthermore, compared to TBPP/PS, Zn-TBPP/PS exhibited an improved flame retardant performance with 26.0%, 14.4% and 31.5% reduction of peak heat release rate, peak CO and CO 2 production respectively, indicating the catalytic flame retardant effect from zinc element. [ABSTRACT FROM AUTHOR]

Four hyperbranched polysiloxanes (HPSis) with different molecular weights and concentration ratios of double bonds to epoxy groups (1:6.5–1:0.7) were synthesized and characterized. Each HPSi was facilely grafted onto surfaces of Kevlar fibers (KFs) to develop novel modified fibers (HPSi-g-KFs). The structures and integrated properties of HPSi-g-KFs as well as the origin behind were systematically investigated. Results show that HPSi-g-KFs have much rougher surface morphologies, and their surface free energies are as high as about 1.7 times that of KFs, showing greatly improved wettability. Besides, HPSi-g-KFs have excellent UV resistance after 168 h UV irradiation, the retentions of tenacity, energy to break, modulus and break extension are as high as 92, 86, 95 and 96%, respectively, while those of KFs are 66–85%. In addition, compared with KFs, HPSi-g-KFs have higher tensile tenacity and energy to break with similar modulus and break extension, much better thermal stability and flame retardancy. The nature of HPSi has different influence on different property of fibers, the HPSi with smaller molecular weight and more epoxy groups is beneficial to prepare HPSi-g-KFs with better wettability, while that with larger molecular weight and more double bonds tends to prepare HPSi-g-KF with better flame retardancy and UV resistance. [ABSTRACT FROM AUTHOR]

• Highly anti-UV PMIA was prepared by a modified atomic layer deposition strategy. • Modified PMIA retain the excellent laundering durability and thermal stability. • TiO 2 film have a negligible effect on the luster and flexibility of modified PMIA. Aramid fiber holds a great potential application in harsh environments like defense and aerospace due to outstanding integrated properties, but it still falls short in poor UV resistance and surface inertness. It is an intriguing but challenging task to obtain high anti-UV efficiency for aramid fiber without compromising the mechanical characteristics. Herein, a uniform and thickness-controlled amorphous TiO 2 coating is chemically-bonded onto aramid fiber surfaces via a modified atomic layer deposition (mALD) strategy. Although mALD TiO 2 has an amorphous structure, its special chemical bonding state similar to LBL enables it to absorb UV light to a certain extent, but at the same time endows it with low photocatalytic activity. In contrast to bare aramid fiber with poor UV resistance and greatly suppressed mechanical performance, the modified aramid fibers with 1000 ALD cycles possesses well-preserved mechanical strength and flexibility. Moreover, they exhibit 54.08% retention of initial tenacity even exposure to UV irradiation with intensity of 4260 W/m2 at high temperature (> 200 °C) for 360 min (equals to continuous exposure to strong sunlight irradiation for about 7.5 years), simultaneously retain the excellent laundering durability and lustrousness, demonstrating a significant enhancement in anti-UV efficiency. Such highly anti-UV fibers fabricated by a facile mALD strategy provide a new perspective on designing multifunctional fibers and devices for future innovative applications. [ABSTRACT FROM AUTHOR]