UV Resistance Properties Research Articles

Facile fabrication of multifunctional aramid fibers for excellent UV resistance in extreme environments

Aramid fibers (AFs) are widely applied as structural material, cordage, and versatile protection in many harsh environments, including space and deep sea. However, intense ultraviolet (UV)/ irradiation, high/low temperatures, and/or chemical solvent with strong acid/alkali/corrosion feature seriously affect their mechanical properties, thus severely shorten the life cycle of AF-based products. Inspiration by the principle of multiple refractions and partly reflections, an innovative strategy by depositing of laminated Al2O3/TiO2 composite onto the surface of poly(m-phenylene isophthalamide) (PMIA) via atomic layer deposition (ALD) technique was presented. The tenacity of ALD-coated PMIA only decreases by ∼ 8 %, and the yellowness index (YI) only increasing to 129.24 %, far lower than 321.63 % of pristine PMIA fabric under the combination of intense UV irradiation (4260 W/m2) and high temperature (200 °C + ) for 6 h, which equals to continuous strong sunlight exposure for approximately 7.5 years. Meanwhile, ultraviolet protection factor (UPF) value increased to 126.4, which is double that of the pristine PMIA fabric, exhibiting an impressive UV-resistance property. Furthermore, the ALD-coated PMIAs also shows a significant enhancement in both chemical and thermal stabilities. In all, this work not only forge a new route for the functionalization of fibrous materials, but also exhibits great promise for next generation advanced composite material and cutting-edge equipment in harsh environment.

Ultraviolet Shielding Performance of Coconut Coir as a Filler in Low-Density Polyethylene (LDPE) Plastic Mulch

Plastic mulch is a layer of material applied to the soil surface to maintain moisture retention in the soil by preventing evaporation, reduce weed growth by blocking sunlight from reaching underlying weeds, and optimize fertilizer use by minimizing nutrient loss to the environment. However, the degradation of low-density polyethylene (LDPE), a thermoplastic commonly used for mulching, into microplastics due to exposure to UV radiation. This research explored the potential of coconut coir, a natural fiber with a high lignin content ranging from 30 to 46%, as a UV protective agent. The objective was to develop biodegradable plastic-based mulch composites that have better resistance to UV exposure by incorporating coir as a filler material in LDPE-based composites. Different ratios of coconut fiber were used (10%, 20%, 30%, and 40%), and Maleic anhydride grafted polyethylene (PE-g-MAH) was used as a binder at 2% of total weight mixed with LDPE in a rheomixer (80 rpm, 120°C for 10 min). The resulting plastic mulch bio-composites were evaluated for thermal, mechanical, UV resistance, and biodegradability properties. The results showed that the higher addition of coconut coir resulted in a decrease in the thermal and mechanical characteristics of the composite. However, the addition of higher coconut coir in the composite at 40% can provide an increase in the composite's resistance to ultraviolet light exposure, and the properties are easily degraded by the environment (biodegradable).

Multifunctional flexible composite membrane based on nanocellulose-modified expanded graphite/electrostatically spun fiber network structure for solar thermal energy conversion

To enhance the application range of flexible films, it is crucial to rationally design composite films with high stretchability, excellent thermal conductivity, and water resistance. Flexible composite films with nanocellulose (CNF)-modified expanded graphite and spun fibers loaded with phase change materials as the backbone were obtained by electrospinning method. The prepared materials were characterized by good tensile properties (328.32%), high latent heat (107.0 J/g), good thermal stability, high photo-thermal conversion efficiency, good reusability, flame retardant properties, UV resistance and visible light absorption properties. What's more, the performance of the flexible composite membrane is adjustable. The prepared flexible composite membranes are promising in the fields of solar thermal energy conversion, wearable flexible materials and renewable energy utilization.

Sustainable, transparent, strong toughness, UV resistance, and anti-corrosion properties of cashew shell oil-based waterborne polyurethane network derived from phloretin and sorbitan monooleate-based siloxane

The increasingly severe energy shortage and growing environmental problems have accelerated the rapid development of sustainable polymer materials. Hereon, a novel method was proposed for the synthesis of cashew nut shell oil-based waterborne polyurethane (WPUs), which exhibited excellent toughness, transparency, water resistance, UV resistance and corrosion resistance. Specifically, the sorbitan monooleate-based siloxane (MSP) was prepared via a thiol-ene click chemistry reaction. Subsequently, the plant-based phloretin (PRT) and MSP were introduced as polyols into the skeleton of WPUs through the molecular structure design strategy. Series of high bio-based content (91 %) WPUs networks were obtained via pre-polymerization and self-emulsification methods. The properties of their dispersions and films were thoroughly investigated, and it was found that the addition of MSP and PRT enhanced the overall performance of WPUs film. For instance, there was a significant increase in Tg. Additionally, they exhibited a maximum tensile strength of 31.5 MPa and a maximum toughness of 53 MJ/m3, which were the most outstanding among all reported plant oil-based WPU systems so far, indicating excellent tear resistance. Interestingly, the water absorption rate of PSWPU-40 was reduced to 7.1 %, suggesting good water resistance, which resolved the contradiction between the mechanical properties and water resistance of the current plant oil-based WPU systems. The PSPWU films exhibited promising application prospects, exemplified by its ability to effectively shield the entire UV range. Furthermore, its coating demonstrated outstanding anti-corrosion properties with a maximum anticorrosion efficiency of 97.1 %. It could be attributed to the synergistic effect of a self-crosslinking structure, higher crosslinking density, a tighter network structure, and stronger intermolecular forces (H-bond). This work provided a meaningful guide for the application and development of high-performance bio-based WPU functional coatings.

Nanotechnology in Construction: Innovations, Applications, and Impacts

Nanotechnology has emerged as a transformative force in the construction industry, revolutionizing traditional building materials and methods. This paper delves into the multifaceted applications of nanotechnology in construction, focusing on its impact on building coatings, materials, colors, insulation, and sensors. By incorporating nanoparticles like carbon nanotubes and titanium dioxide, construction materials gain enhanced mechanical properties and durability. Nano-coatings applied to surfaces such as glass, wood, and concrete offer benefits like water repellence, UV resistance, and antibacterial properties, contributing to energy efficiency and cost savings. Furthermore, advancements in self[1]healing concrete, fire-resistant glass, and smart surfaces demonstrate the potential of nanotechnology to address longstanding challenges in construction. The paper also explores the use of nanotechnology in paints, insulation, and sensors, highlighting innovations such as self-cleaning paints, antistatic coatings, and nano-acoustic insulators. Overall, the integration of nanotechnology into the construction sector promises improved product quality, energy efficiency, and longevity, heralding a new era of sustainable and resilient built environments.

Toward Flame Retardancy, Antimelt Dripping, and UV Resistance Properties of Polylactic Acid Based on Eco-Friendly Core–Shell Flame Retardant

Toward Flame Retardancy, Antimelt Dripping, and UV Resistance Properties of Polylactic Acid Based on Eco-Friendly Core–Shell Flame Retardant

One-pot co-crystallized hexanal-loaded ZIF-8/quaternized chitosan film for temperature-responsive ethylene inhibition and climacteric fruit preservation

Controlling ethylene production and microbial infection are key factors to prolong the shelf life of climacteric fruit. Herein, a nanocomposite film, hexanal-loaded ZIF-8/CS (HZCF) with “nano-barrier” structure, was developed by a one-pot co-crystallized of ZIF-8 in situ growth on quaternized chitosan (CS) and encapsulation of hexanal into ZIF-8 via microporous adsorption. The resultant film realized the temperature responsive release of hexanal via the steric hindrance and hierarchical pore structure as “nano-barrier”, which can inhibit ethylene production in climacteric fruit on demand. Based on this, the maximum ethylene inhibition rate of HZCF was up to 52.6 %. Meanwhile, the film exhibits excellent antibacterial, mechanical, UV resistance and water retention properties, by virtue of the functional synergy between ZIF-8 and CS. Contributed to the multifunctional features, HZCF prolonged the shelf life of banana and mango for at least 16 days, which is 8 days longer than that of control fruit. More strikingly, HZCF is washable and biodegradable, which is expected to replace non-degradable plastic film. Thus, this study provides a convenient novel approach to simplify the encapsulation of active molecule on metal-organic frameworks (MOFs), develops a packaging material for high-efficient freshness preservation, and helps to alleviate the survival crisis caused by food waste.

Bioprospects of pink pigmented facultative methylotrophs (PPFMs)

PurposeThe purpose of this article is to provide information about interactions between pink-pigmented facultative methylotroph (PPFM) organisms and plants, their molecular mechanisms of methylotrophic metabolism, application of PPFMs in agriculture, biotechnology and bioremediation and also to explore lacuna in PPFMs research and direction for future research.Design/methodology/approachResearch findings on PPFM organisms as potent plant growth promoting organisms are discussed in the light of reports published by various workers. Unexplored field of PPFM research are detected and their application as a new group of biofertilizer that also help host plants to overcome draught stress in poorly irrigated crop field is suggested.FindingsPPFMs are used as plant growth promoters for improved crop yield, seed germination capacity, resistance against pathogens and tolerance against drought stress. Anti-oxidant and UV resistant properties of PPFM pigments protect the host plants from strong sunshine. PPFMs have excellent draught ameliorating capacity.Originality/valueTo meet the ever increasing world population, more and more barren, less irrigated land has to be utilized for agriculture and horticulture purpose and use of PPFM group of organisms due to their draught ameliorating properties in addition to their plant growth promoting characters will be extremely useful. PPFMs are also promising candidates for the production of various industrially and medicinally important enzymes and other value-added products. Wider application of this ecofriendly group of bacteria will reduce crop production cost thus improving economy of the farmers and will be a greener alternative of hazardous chemical fertilizers and fungicides.Graphicalabstract:

Preparation of molecularly well-defined silicone resins based on trifluoropropyl-substituted trisilanol and their thermal, mechanical, and UV-resistance properties

Preparation of molecularly well-defined silicone resins based on trifluoropropyl-substituted trisilanol and their thermal, mechanical, and UV-resistance properties

Agricultural waste Ipomoea batatas leaves for low-temperature dyeing and functional finishing of polyester fabrics

The increasing focus on eco-friendly textiles and cleaner production manufacturing techniques have made natural pigments for coloring and enhancing the functionality of textiles become a popular trend. This research aimed to extract plant pigment from bio-waste Ipomoea batatas leaves and utilize it for dyeing and functional decoration of polyester fabric at low temperature. The study optimized the parameters for pigment extraction and fabric dyeing and also investigated the stability of the pigment solution. The finding indicated that strong acids and bases, intense light, high temperatures, and oxidants have a greater impact on pigment stability. Observation and analysis using SEM, bio-optical microscope, FTIR, and UV–vis–NIR absorption spectroscopy revealed that chlorophyll pigment entered into the interior of polyester molecular chains through hydrophobic end intercalation and was retained by the physical forces, enabling low-temperature coloring and functional finishing of polyester fabrics. As a result, the polyester fabrics dyed with natural pigment exhibited excellent resistance to rubbing, washing, saliva, and perspiration (rated at level 4 or higher), except for the average light fastness (only grade 4). Additionally, the dyed polyester fabrics demonstrated outstanding UV resistance (UPF of 33.57 for raw polyester and 120.77 for pre-mordant dyed polyester) and antibacterial properties (raw polyester agar plates showed bacterial growth, while the colored polyester agar plates had almost no bacterial growth). Even after 10 wash cycles, the dyed polyester fabrics maintained their UV protection and antibacterial properties. This research is expected to provide a new approach to the valuable utilization of agricultural residues in the textile industry.

Isolation of microcrystalline cellulose (MCC) from pistachio shells and preparation of carrageenan-based composite films

Utilizing agricultural waste for material innovation, particularly in food packaging, is an emerging trend aimed at enhancing sustainability and reducing environmental impact. In this study, the goal was to valorize agricultural waste by isolating microcrystalline cellulose (MCC) from pistachio shell powder (PSP) and integrating it into carrageenan films as a filler. Alkaline hydrogen peroxide (AHP) was used to extract PSP fiber at various AHP liquor ratios (NaOH:H2O2), followed by hydrochloric acid hydrolysis of the PSP fibers. Detailed analyses assessed the impact of AHP concentration on the thermal, morphological, microscopic, and crystalline properties of the resulting MCC. Elevated NaOH and H2O2 ratio in the AHP process notably improved the MCC's thermal stability and crystallinity index. FTIR spectroscopy indicated the efficient removal of amorphous regions and impurities, such as lignin and hemicellulose, during AHP pre-hydrolysis. The 4.0:4.4 AHP liquor ratio emerged as particularly promising, considering thermal stability, impurity removal, and crystallinity index. Carrageenan films with the derived MCC showed improved UV resistance, oxygen barrier, thermal stability, and mechanical properties. This research highlights the potential of pistachio shell-derived MCC as a sustainable filler, emphasizing a novel strategy for repurposing agricultural waste.

Itaconic acid-based sustainable polyurethane covalent adaptable networks with robust mechanical, reshaping and UV-resistant properties based on reversible disulfide bond

Thermoset polymer materials are widely used in various fields due to their excellent performance brought by their permanently cross-linked structures. However, their inability to be recycled also leads to a serious waste of resources. The emergence of covalent adaptable networks (CANs) has solved the problem perfectly that thermoset materials are difficult to recycle. Meanwhile, with the increasing concern for resources and the environment, bio-based materials have sparked a research boom. Itaconic acid is a biomass feedstock with great prospects for development. In this study, itaconic acid, 1,6-hexanediol, 6-mercapto-1-hexanol, isocyanate, and 4,4′-dithiodiphenylamine were used as raw materials. Itaconic acid-based polyols were first synthesized by thiol-ene click reaction, and a series of itaconic acid-based polyurethane (PU) materials containing dynamic covalent networks were synthesized by varying the ratios between the amino and hydroxyl groups. The obtained material has good mechanical properties with a maximum tensile strength of 31.5 MPa and a modulus of 717 MPa. The presence of disulfide bonds allows the material to be recycled by remodeling, and the recovery efficiency of tensile strength after three remodeling cycles is 85.1 %. The material also has excellent solvent resistance and UV-blocking resistance. In conclusion, this work provides possible ideas for the high-value utilization of itaconic acid in polyurethanes.

LAYER-BY-LAYER SELF-ASSEMBLY APPROACH IN THE UV PROTECTIVE MODIFICATION OF ARAMID-BASED MATERIALS

This paper presents the Layer by Layer self-assembly (LbL) approach for developing the UV resistance of aramid yarns. Initially, a pretreatment was achieved by polyethyleneimine to obtain cationic surface charges on aramid yarns. Then zinc oxide and titanium dioxide nanoparticles were self-assembled on these yarns by the LbL process. The findings revealed that the LbL nano coatings significantly improved the UV resistance and tensile properties of the aramid yarns. This study highlights the unique opportunities offered by the LbL methodology to both modify aramid-based materials in mild conditions and provide an effective UV protection.

Durable Multifunctional Modification of Nylon Fabric with Excellent Flame Retardancy, Antibacterial and UV-Resistant Properties

Durable Multifunctional Modification of Nylon Fabric with Excellent Flame Retardancy, Antibacterial and UV-Resistant Properties

Nacre-inspired composite paper of PVA crosslinked basalt scale and nanocellulose with enhanced mechanical, electrical insulating and ultraviolet-resistant aging performance

Silicate scales are commonly incorporated into cellulose nanofiber (CNF) as functional fillers to enhance electrical insulation and UV-shielding properties. Nevertheless, the addition of substantial quantities of silicate scales in the quest for enhanced functional properties results in reduced interface bonding capability and compromised mechanical properties, thereby restricting their application. Here, inspired from nacre, layered composite paper with excellent mechanical strength, electrical insulation and UV-resistance properties was fabricated through vacuum assisted self-assembly using CNF, PVA and basalt scales (BS). Unlike the conventional blending strategy, the pre-mixed PVA and BS suspension facilitates the formation of Al-O-C bond, thereby enhancing the interfacial bonding between BS and CNF. Consequently, the composite paper (BS@PVA/PVA/CNF) containing 60 wt% BS demonstrates higher mechanical strength—approximately 140 % higher than that of BS/CNF composite paper, achieving a strength of 33.5 MPa. Additionally, it demonstrates enhanced dielectric properties, surpassing those of CNF paper by up to 107 %. Moreover, it exhibits robust ultraviolet-resistant aging performance, retaining ~87 % of its tensile strength after undergoing a simulated two-year aging period. As a result, this work presents a simple and innovative design strategy for enhancing interfacial bonding and optimizing layer structure, providing essential guidelines for large-scale production of high-performance insulation and aging-resistant composite paper.

Cover Image

A high‐performance and sustainable structural functional material has been developed from natural pinewood, enabled by the unique ionic bond. The obtained material shows good water resistance, thermal conductivity, thermal stability, UV resistance, corrosion resistance and antibacterial properties. This material has promising applications in waterproof enclosure structure, underfloor heating, UV resistant protective cover, and anti‐corrosion materials, etc. image

Fluorinated polyimide with enhanced ultraviolet-resistant radiation via a self-sacrificial strategy

High-performance polyimide (PI) films with excellent ultraviolet (UV)-resistant radiation and low dielectric constant (k) properties are ideal spacecraft antenna substrates in space applications. However, conventional commercial PI films like Kapton® applied in the aerospace field are inevitably subjected to the harsh UV radiation environment, leading to their structural damage and performance failure. Herein, a type of “self-sacrificial” micro-branched crosslinked PI films were fabricated by employing tris(4-aminophenyl)amine (TAPA) intrinsically containing the C-N bonds to crosslink linear pure fluorinated PI (FPI), where TAPA functioned as the dual roles of crosslinker and creating “self-sacrificial” local deep traps of C-N bonds in crosslinked sites. Consequently, abundant local deep traps of C-N bonds in crosslinked sites could capture energy from UV-rays to prevent the destruction of PI molecular main chains, thus the crosslinked FPI-TAPA films exhibited better UV-resistant radiation properties than that of pure FPI films and commercial PI films. And the crosslinked film showed least k of 2.53 and least dielectric loss of 0.006 at frequency of 1 MHz owing to the introduction of micro-branched crosslinked structure. Additionally, a high breakdown strength of 522 MV/m, as well as a high tensile modulus of 3.03 ± 0.07 GPa, was achieved, much better than the value of pure FPI film. This work provides a novel and facile approach to fabricate high-performance PI films with excellent UV-resistant properties, exhibiting great potential application in aerospace and microelectronics industries.

Facile synthesis of phosphorus-containing benzotriazole flame retardant for enhancement of mechanical and fire properties of epoxy resins

The preparation of flame retardant, strong yet tough, and transparent epoxy resin (EP) composites faces significant challenge. In this study, a phosphorus-containing benzotriazole flame retardant PDI was successfully synthesized. It was important to highlight that the EP/PDI-11 % achieved a limiting oxygen index (LOI) of 32 % and was classified as UL-94V-0 rating. Furthermore, it exhibited a significant reduction in both total smoke production (TSP) and peak heat release rate (pHRR), which decreased by 64.1 % and 46.9 % respectively when compared to EP. Meanwhile, PDI simultaneously enhanced the mechanical strength and toughness of EP, and adding 5 wt% PDI resulted in a 27.2 % improvement in tensile strength, a 53.3 % increase in elongation at break and a 91.4 % increase in impact strength for EP-5 %. Notably, PDI had the ability to promote curing, and the curing peak temperature of EP was advanced by about 20 ℃. In addition, PDI enhanced the insulation and UV resistance properties of EP/PDI, and the high transparency of EP/PDI composites also maintained.

Multifunctional packaging film with sustained release behavior triggered by pH microenvironment for efficient preservation of pork

To tackle microbial contamination and spoilage during pork storage, transportation, and sales, a novel packaging film with exogenously driven controlled release behavior was designed through the demand-directed preparation of the emulsion of shellac-encapsulated cinnamaldehyde nano-capsules (SNCs) and the ingenious integration of chitosan (CS) film matrix. Among them, the SNCs were synthesized using the solvent exchange method, allowing controlled release of cinnamaldehyde (CA) in response to volatile alkaline substances present in the meat. The electrostatic interaction between SNCs and CS molecules improved the thermal stability, water resistance, tensile strength, and viscosity of the film-forming solution, while the CA in SNCs enhanced UV resistance and antimicrobial properties of the film. Notably, the CS film with SNC-100 loaded (CSNCs-100 film) achieved 99% inhibition against both E. coli and S. aureus, regulated environmental moisture, and prolonged the freshness duration of pork by an impressive six days.

Hybridization of cellulose nanocrystals modified ZnO nanoparticles with bio-based hyperbranched waterborne polyurethane sizing agent for superior UV resistance and interfacial properties of CF/PA6 composites

The interface of carbon fiber (CF) reinforced composites has been a long challenging issue that restricts the full utilization of its excellent properties in industrial applications. In present work, a green solvent γ-valerolactone and biogenetic derived gallic acid and tartaric acid were used to prepare a hyperbranched waterborne polyurethane (HWPU) sizing agent. Meanwhile, cellulose nanocrystal modified zinc oxide (CNC–ZnO) nanohybrids were successfully synthesized using a facile one-pot method to improve the dispersibility and specific surface area of ZnO nanoparticles. The hybridization of CNC–ZnO substantially enhanced the thermostability and UV resistance of bio-based HWPU. The mechanical properties of the modified composites were thoroughly examined, revealing remarkable enhancements in flexural strength and interlaminar shear strength, with improvements of 46.5 % and 48.1 % compared to pristine CF. Additionally, the interfacial shear strength test demonstrated a significant increase of 63.6 %. Remarkably, the modified carbon fiber composites retained more than 97 % of their mechanical properties after being subjected to continuous xenon irradiation for a week, highlighting the exceptional ultroviolet resistance derived from the hybrid HWPU sizing agent.