Significant Mechanical Damage Research Articles

Probing the remarkable vitrimeric performance of Poly(dithiourethanes): A comprehensive investigation into the dynamic behavior

Vitrimers and vitrimer-like systems are renowned for their exceptional mechanical and thermal characteristics, coupled with their inherent recyclability. In this study, a novel class of vitrimer-like systems is introduced, wherein a tetrathiol and diisothiocyanate are blended to create poly(dithiourethanes), catalyzed by a basic catalyst. An innovative covalent adaptable network (CAN) is synthesized, featuring a glass transition temperature (Tg) of 332 K as determined by calorimetry, with a tensile modulus of 2240 MPa. The material’s properties are investigated through solubility, stress-relaxation, and creep experiments, revealing relaxation times as short as 0.7 min at 363 K, indicative of its robust dynamic behavior. Dielectric spectroscopy is employed to analyze the various relaxation processes characteristic of such materials, particularly when the topology freezing transition (Tv) occurs below the Tg. This technique complements the findings of dynamic thermomechanical analysis (DMA), enhancing our understanding of the material’s behavior. Furthermore, the materials exhibit recyclability through a grinding and compression molding cycle without significant mechanical damage. Their dielectric constant and low loss factor, combined with the reversibility of their chemical structures, position them as promising candidates for energy-related applications.

Experiment and analysis of physical, mechanical, and viscoelastic properties of the roots and stalks of green leafy vegetables.

Green leafy vegetables are an essential component of Chinese leafy vegetables. Due to their crisp stems and tender leaves, orderly harvester generally causes significant mechanical clamping damage. The physical and mechanical properties of green leafy vegetables are one of the important basis to design the orderly harvester. At the same time, they provide important parameters for the simulation and optimization of harvester. So, this paper measured the physical characteristic parameters of roots and stems of green leafy vegetables. Then, based on the TMS-Pro texture analyzer, the elasticity modulus of the roots and stems of green leafy vegetables were measured. The static friction coefficient, dynamic friction coefficient, and restitution coefficient of green leafy vegetables root-root, stem-stem, root-steel, and stem-steel were measured separately using a combination method of inclined plane and high-speed photography. Uniaxial compression creep experiments were carried out on whole and single leaf of green leafy vegetables using the TA.XT plus C universal testing machine. The constitutive equation of the four-element Burgers model was used to fit the deformation curve of the sample with time during the constant-pressure loading stage. The fitting determination coefficients R2 were all higher than 0.996, which verified the reasonable validity of the selected model. The above experimental results provide a parameter basis and theoretical support for the design and discrete element simulation optimization of orderly harvester critical components of green leafy vegetables.

The Culprit behind the Mass Death of Mangroves: Egrets or Rats (Rattus losea)?

Mangroves play a crucial role in maintaining coastal ecological balance. This study focused on the impact of branch-breaking behavior on the mortality of Rhizophora stylosa in the Guangxi Shankou Mangrove Reserve. However, we found mangrove mortality in areas devoid of egret habitation, prompting a reevaluation of our research hypothesis. Further investigation suggested that nesting behavior was the primary cause of mangrove mortality. A comparison of the data from areas with egrets (Egretta garzetta, Ardea intermedia) and lesser rice-field rats (Rattus losea) activity indicated significant mechanical damage caused by rats to mangroves as the main cause of mortality. Additionally, we found that the biological characteristics of R. stylosa, particularly its stunted growth and recovery abilities after branch breaking, were key factors affecting its survival. These findings imply that rat-induced mortality may not occur in other less susceptible mangrove species. The results contradict assumptions regarding the impact of egret behavior and highlight the importance of the biological characteristics of R. stylosa. This offers fresh insights into mangrove conservation and management, emphasizing the need for ongoing observation and hypotheses verification. Future studies should explore the influence of lesser rice-field rats’ activity and the intrinsic characteristics of R. stylosa on the ecosystem’s long-term stability.

Parasites in Imported Edible Fish and a Systematic Review of the Pathophysiology of Infection and the Potential Threat to Australian Native Aquatic Species

Previous research has shown that certain types of edible fish imported into Australia are infected with Euclinostomum/Isoparorchis digenetic trematodes. In the present study, imported Channa fish were examined for parasites which were then morphologically identified to the lowest taxonomic unit possible. Here we provide the first Australian report of Pallisentis sp. Van Cleave, 1928 (Prevalence (P) 35.9%) of family Quadrigyridae; Genarchopsis sp. Ozaki, 1925 (P. 16.5%), family Derogenidae and Senga sp. Dollfus, 1934 (P. 4.8%) in edible imported Channa fish (n = 103). Pallisentis sp. and Senga sp. have invasive hold fast organs which cause significant mechanical damage to fish intestinal structures and Euclinostomum/Isoparorchis cause severe pathology and loss of marketability in infected fish. These exotic parasites, if introduced into Australia, have the potential to negatively impact the health, fecundity, resilience and marketability of native and commercial fish species. Biosecurity is a constant ontogenesis of novel hypothesis based on current scientific discoveries. To further increase understanding of how parasitism impacts fish health, a systematic literature review was conducted and the pathophysiology of infection described. Potential exposure pathways and parasite host associations in Australia are discussed.

A self-healing, high stretchable and wide-temperature tolerance hydrogel electrolyte for high-performance supercapacitor

All-solid-state flexible supercapacitors provide favorable conditions for the development of portable and wearable devices. The development of electrolytes with excellent self-healing, mechanical and electrochemical properties have become an effective strategy to address the significant mechanical strain and damage of conventional solid state supercapacitors. Herein, a novel PAM/β-CD/EMIMBF4 hydrogel electrolyte with slide-ring structure and hydrogen bonds was synthesized by copolymerization method. The PAM/β-CD/EMIMBF4 hydrogel exhibits outstanding ionic conductivity ((35 mS cm‐1−1), remarkable self-healing behavior (healing efficiency of 91.3%)) and large tensile strain (over 1000 %). Furthermore, the supercapacitor with PAM/β-CD/EMIMBF4 hydrogel electrolyte has a large specific capacitance (124 F g−1) and maintains 82.9 % of its initial value after 5000 cycles. This study designed a multifunctional hydrogel electrolyte, which provides a promising insight for the development of emerging electronic products with customization functions.

Determination method for metal bridge superstructure replacement priority using strength, economic and operational criteria

The article describes the problem arising from the setting trains with increased axleloads into operation on bridges with superstructures, engineered according to the old design standards. On the railways used riveted metal bridge superstructures, which require replacement due to significant corrosion, mechanical and fatigue damage, due to insufficient carrying load and residual fatigue life to pass the prospective load. Superstructures, designed in the 30s-40s, are more than 80-90 years used in conditions of a relatively difficult operation. During long-term operation, processes occur in elements and joints that lead to the formation and development of various hazard degrees damages, and failures. It is necessary to resolve the further exploitation issue of old bridge superstructures and their replacement. The author has applied the analyzing method of the criteria system, with the account of economic and technical capabilities for replacement priority determination of bridge superstructures. A set of criteria were proposed for solving this problem in digital form. Compiled matrices of pair-wise comparison, the comparison was performed using a relative importance scale with the test significance determination. By the linear algebra methods the eigenvector of matrix components values — local priorities — are calculated for each pair-wise comparisons matrix. As a result of calculations by the proposed criteria, were obtained global priorities for replacing options for riveted metal superstructures made by old design standards. The mathematical apparatus of the criteria hierarchy method is easy to use and allows you to get a solution in digital form, you can use other criteria.

THE EFFECT OF MECHANICAL BARK DAMAGE ON THE VOLUME INCREMENT OF TREES

UDK: 630*232:582.475(497.6)
 It is well known that mechanical damage to trees, caused by felling and removal of timber from the forest, has multiple negative effects on the quality of the stock and the health of the forests as well as the volume increment. In Bosnia and Herzegovina there were no significant analises of volume increment loss due to bark damage of the trees. In this paper, a direct relationship between the significant damage to the bark of the stem and the size of the volume increment of individual trees was determined. Original data recorded during the Second National Forest Inventory in Bosnia and Herzegovina (2006-2009), within the accesible high economical forests was used. These forests cover a total area of 1.329.500 ha.
 Data on measured trees was taken from every fourth sample plot (one from cluster). 18.546 trees were selected, on which the 10-year increment of brest diameter (DBH) was measured and significant mechanical damage was recorded (LOJO et al., 2008). Of the total number of selected trees, 2.635 or 14.21% were mechanically damaged.
 The results of the study showed that the volume increment of trees, with significant bark damage of all tree species and thickness, was lower from 4,9% to 19,4% in average, compared to undamaged trees.
 Based on registered damage the bark of the stem, during second NFI BiH and determined the average losses increment on individual trees, it was estimated how much these losses are on an annual basis in, productive high forests in Bosnia and Herzegovina.
 The volume increment of mechanically damaged trees is statistically significantly lower compare to the increment of undamaged trees, resulting in a total loss of about 200.000 m3 / year / 1.329.500 ha.

Facile fabrication and repair of superhydrophobic metal surfaces via electric spark deposition with oil

Recent research has focused on the durability of superhydrophobic surfaces, and some methods have reported improvements in the resistance of surfaces to abrasion from several sandpaper treatment cycles with the goal of maintaining a contact angle (CA) > 150°. However, the surface water repellency is lost because of the numerous abrasive cycles causing significant mechanical damage. Repairing the superhydrophobicity of the material is necessary when the surface is damaged. Current repair methods have different limitations, such as special abrasion conditions or limits on the substrate size and working conditions. Here, we demonstrate that using electric spark deposition with oil can create a superhydrophobic surface in a single step. This represents a facile method that can be carried out by hand with fewer limitations on its working conditions and the substrate location and shape. The morphology and chemical composition of the coating was investigated. The addition of octadecanoic acid to the oil provided a stable CA > 150° for the coated surface. The coated surface lost superhydrophobicity after being subject to three different damaging processes, and the superhydrophobicity could be recovered after recoating.

Enhancing the Shelf-Life of Fresh Cassava Roots: A Field Evaluation of Simple Storage Bags

Postharvest physiological deterioration (PPD) of fresh cassava roots limits their shelf-life to about 48 h. There is a demand for simple, cheap, and logistically feasible solutions for extending the shelf life of fresh cassava roots in industrial processes. In this study, three different types of bag materials were tested, namely woven polypropylene, tarpaulin, and jute as a potential storage solution for cassava roots with different levels of mechanical damage. Microclimate related to temperature, humidity, and carbon di-oxide (CO2) was monitored in order to understand the storage conditions for up to 12 days. The results showed that fresh cassava roots could be stored for 8 days, with minimal PPD and starch loss (2.4%). However, roots with significant mechanical damage in the form of cuts and breakages had a considerably shorter shelf life in the storage bag, compared to whole roots and roots with retained stalk (peduncle) where roots are connected to the main plant. Wetting of the roots and bag material were not significant factors in determining the shelf life and starch loss. Carbon dioxide concentration in the stores was significantly correlated with the starch loss in fresh cassava roots and is proposed as a possible method for continuously and remotely monitoring starch loss in large-scale commercial operations and reducing postharvest losses.

Novel Low-Twist Bast Fibre Yarns from Flax Tow for High-Performance Composite Applications.

The use of natural fibres for components subjected to higher mechanical requirements tends to be limited by the high price of high-quality semi-finished products. Therefore, the present study deals with the development of more cost-effective staple fibre yarns made from flax tow. In the subsequent processing stage, the yarns were processed into quasi-unidirectional (UD) fabrics. The results of the fibre characterisation along the process chain have shown that no significant mechanical fibre damage occurs after slivers’ production. Fibres prepared from yarns and fabrics show comparable characteristics. The yarns were processed to composites by pultrusion to verify the reinforcement effect. The mechanical properties were comparable to those of composites made from a high-quality UD flax roving. The fabrics were industrially processed into composite laminates using a vacuum infusion and an autoclave injection process (vacuum injection method in an autoclave). While impact strength compared to a reference laminate based on the UD flax roving was achieved, tensile and flexural properties were not reached. An analysis showed that the staple fibre yarns in the fabric show an undulation, leading to a reorientation of the fibres and lower characteristic values, which show 86–92% of the laminate made from the flax roving. Hybrid laminates with outer glass and inner flax layers were manufactured for the intended development of a leaf spring for the bogie of a narrow-gauge railroad as a demonstrator. The hybrid composites display excellent mechanical properties and showed clear advantages over a pure glass fibre-reinforced composite in lightweight construction potential, particularly flexural stiffness.

Performance of SiO2-impregnated flax fibre reinforced polymers under wet dry and freeze thaw cycles

Flax fibres are of growing interest as a reinforcing fibre; however, they are susceptible to moisture and have demonstrated poor bond to conventional hydrophobic resins. Although there are multiple approaches to address these issues, research has heavily focused on their short-term performance. In this research program, the performance of flax fibre reinforced polymer (FFRP), manufactured using SiO2-impregnated flax fibre, is assessed for its short-term performance as well as its long-term performance when exposed to wet-dry (WD) and freeze-thaw (FT) cycles. Treated FFRP showed improved bond between the fibre and resin as well as resistance to fibre pull-out. It exhibited a tensile strength of 144 ± 15 MPa and a tensile modulus of 8.6 ± 0.35 GPa. When exposed to WD cycles, delamination between the fibre and resin were observed. The onset of statistically significant mechanical damage occurred after four WD cycles, with a final 3% reduction in strength and a 6% reduction in modulus post-exposure. When exposed to FT cycles, FFRP experienced cracking within the fibre, as well as delamination at the interface. The onset of statistically significant mechanical damage occurred after 50 FT cycles, which manifested as a final 5% reduction in tensile strength and 10% reduction in tensile modulus post-exposure. Regardless of treatment, FFRP demonstrated the same damage mechanisms as untreated variants.

A Method for Preparation of Samples of Titanium–Containing Bone–Implant Units for Assessing Osseointegration

Diaphyseal defects of canine tibia bones were replaced with bioactive cylindrical mesh implants made of Ti–6Al–4V titanium alloy. Bone−implant units were cut with a precision cutter using abrasive cutting discs (thickness, 0.76 mm; rotational speed, 2000 rpm; feed rate, 12 mm/min for sample 1 and 5 mm/min for samples 2–4). Tissues were found to suffer thermal damage at a disc feed rate of 12 mm/min; 72.6% of tissues in the projection of the defect cavity were found to be unsuitable for histological examination. At a feed rate of 5 mm/min, thermal damage or significant mechanical damage to the tissues was not observed. Thus, at the stage of preparation of samples of titanium–containing bone−implant units for the assessment of osseointegration, the degree of tissue preservation, under otherwise identical conditions, depends on the cutting tool feed rate.

Thermo-mechanical behavior of a granodiorite from the Liquiñe fractured geothermal system (39°S) in the Southern Volcanic Zone of the Andes

Fractures and faults in granitic rocks play an important role in geothermal systems because they permit the circulation of hot fluids. However, the thermo-hydro-mechanical behavior of granitic rocks has predominantly been studied at temperatures exceeding 300 °C but many geothermal systems experience temperatures much lower than this. The aim of this study was to evaluate how the depth, temperature, and amount and rate of mechanical loading associated conditions, that are realistic in low temperature geothermal system, influence the physical properties of geothermal reservoir hosting rock. We carried out both room temperature and low temperature thermo-mechanical tests on a granodiorite sample from the Liquiñe area, Chile, and performed post-experimental X-ray microtomography analysis to numerically estimate the permeability of the generated fractures. The results showed that both rock strength and rock stiffness decreased with increments of temperature treatment related to the development of thermal crack damage at temperatures > 150 °C and through the development of sub-critical cracking at constant temperatures between 50–75 °C. Slowest deformed samples also exhibited lower strengths, attributed to the development of sub-critical cracking. The cyclic triaxial loading test indicated that significant mechanical fracture damage was only initiated above 80% of the peak stress regardless of the number of repeated loading cycles at lower stresses. Low-temperature treatment appears to be a conditioning factor, but not the dominant factor in controlling the physical properties of reservoir hosting rocks. Our findings indicate that thermal crack damage is likely important for developing microfracture related permeability at depths between around 2–6 km where the temperature is sufficiently high to induce thermal cracking. At shallower depths, such was previously estimated the reservoir of Liquiñe, thermal crack damage is only generated adjacent to fractures that remain open and circulate the hot fluids but sub-critical cracking over time reduces the strength of rocks in lower temperature regimes. These processes combined to produce a geothermal reservoir in Liquiñe which likely first required the presence of a highly fractured fault zone.

Multibranched flower-like ZnO particles from eco-friendly hydrothermal synthesis as green antimicrobials in agriculture

Owing to the exponential growth of the human population and the rising food demand, identifying sustainable antimicrobials for higher agricultural productivity becomes essential. In this study, hydrothermal precipitation for synthesizing versatile nanostructured zinc oxide particles (nZnOs), including nanorods (1D), nanoplatelets (2D), and multibranched flower-like particles (3D), was achieved by controlling pH values of source precursors and growth time. Hydrothermal synthesis is an eco-friendly process without the requirement of hazardous organic solvents. The antimicrobial properties of these nZnO particles were evaluated on different soil-borne plant pathogens. These pathogens are serious limiting factors in agriculture. Results indicate that multibranched flower-like ZnO (3D nZnO) showed more remarkable, reliable, and stable antifungal activity compared with other nZnOs. The scanning electron microscopy results also demonstrated significant mechanical damage to pathogens that caused by the branches of flower-like particles from 3D nZnO. Moreover, results of photodegradation and environmental resistance of the synthesized nZnOs revealed their potentials to reduce hazardous chemical pesticides and the eco-friendliness. This work is the first to compare the antimicrobial (i.e., antifungal) properties of various nZnOs and their applications in agriculture. Our results suggest that multibranched flower-like ZnO can be served as promising candidates of green antimicrobials with multiple modes of action in sustainable agriculture.

Study of the influence of water and oxygen on the morphology and chemistry of pyritized lignite: Implications for the development of a preventive drying protocol

Abstract Lignite constitutes a unique testimony of past diversity and evolution of land plants. This material, usually waterlogged, is particularly difficult to dry because of its mechanical sensitivity to moisture changes. In addition, lignite may contain organic and inorganic sulfides, which are susceptible to oxidation once excavated. As a result, the conservation of lignite is particularly complicated and lignite remains scarce in paleobotanical collections. We experimentally test different drying protocols on waterlogged pyritized lignite, while documenting the respective role of water and oxygen on their morphology and chemistry. The results reveal that inorganic sulfides (pyrite) are more prone to oxidation than organic sulfides (thioethers). Critically, water is the main factor responsible for this oxidation, provoking sulfate efflorescence when samples are further exposed to oxygen. On the other hand, an abrupt removal of water provokes significant mechanical damage while sulfur remains mostly present as reduced compounds. The control of water and oxygen exchanges is thus critical for conserving lignite without physical damage and efflorescence. We successfully achieved this by storing the samples in hermetically sealed plastic bags made of semi-permeable films, which slowly release humidity while allowing a gradual influx of oxygen. We advise curators to quickly handle lignite once removed from its waterlogged environment because of the fast kinetics of oxidation, and to choose a drying protocol according to the purpose of the lignite treated. Finally, once dried, we advise to store the lignite in an anhydrous environment.

Numerical estimations of lightning-induced mechanical damage in carbon/epoxy composites using shock wave overpressure and equivalent air blast overpressure

A new approach is proposed for predicting lightning-induced mechanical damage using the shock wave overpressure (SWO) due to lightning arc channel expansion and also its equivalent air blast overpressure (ABO) due to an explosion of chemical potential energy in AS4/3506 carbon/epoxy laminates. The SWOs and equivalent ABOs associated with 124, 247, and 494 kA peak lightning currents were considered. Dynamic responses of the composite laminates due to both the SWOs and ABOs were similar to each other. The spatial variations in the peak compressive and tensile midplane displacements evaluated near the laminate center showed that mechanical damage tended to be symmetric about the laminate midplane. Hashin’s four different damage criteria were implemented to predict fiber/matrix failures. The predicted failure index distributions in the carbon/epoxy plies were nearly identical for both SWOs and ABOs. Except for matrix tension failure predicted at the 494 kA peak current, all damage failure indices increased as the peak current increased, but were smaller than unity, implying no mechanical damage initiation due to lightning strike. These FE results suggest that lightning SWO may not cause significant mechanical damage and it may be possible to interchangeably use either SWO or ABO to predict lightning-induced mechanical damage.

CFD Study of the effects of ingested bodies on the RSI of hydraulic turbines

The ingestion of large bodies in hydraulic turbines can produce blockage in the runner and/or the distributor, modifying the amplitude and uniformity of pressure pulsations and generating large unbalanced forces. These unwanted effects can lead to reduced efficiency and increased vibration levels, which can produce significant mechanical damage. In this work, we present a characterization of the effects of flow blockages due to ingested bodies on the rotor-stator interaction (RSI) of hydraulic turbines by means of computational fluid dynamics (CFD). For this, a reduced-scale model of a pump turbine was implemented using Ansys® CFX v16.2, and numerical simulations were run for normal operation and blockage operation. Studied blockages included rotor and distributor blockages. Pressure pulsations in rotor and distributor were recorded in order to characterize the effect of the blockage on the RSI of the machine.

Stretchable and Self-Healing Integrated All-Gel-State Supercapacitors Enabled by a Notch-Insensitive Supramolecular Hydrogel Electrolyte.

Next-generation wearable electronics are expected to endure significant deformations and mechanical damage. Therefore, self-healing stretchable electrolytes with high ionic conductivity and robust mechanical strength, which have high tolerance of deformations and spontaneously recover electrochemical properties after external damage, are necessary conditions for the realization of flexible supercapacitors. Here, a new type of zwitterionic supramolecular hydrogel cross-linked through rationally designed ionic associations and hydrogen bonds is reported (PAD/H2SO4). The resultant supramolecular network realizes a high ionic conductivity of 57 mS cm-1 and unprecedented mechanical properties such as a high toughness of 35 000 J m-2, a notch-insensitive of up to 2200% strain, and efficient instantaneous self-healing within 5 min. Acting as an electrolyte, a novel flexible supercapacitor design strategy is proposed by integrating capacitive materials directly onto the PAD/H2SO4 hydrogel to achieve exceptional electrochemical performance, which can be repeatable for at least 50 cutting/healing cycles. The facile and versatile strategy for the construction of the integrated all-gel-state supercapacitors with self-healing stretchable electrolytes will provide new directions for future long-life flexible devices.

A Novel Method of Protection to Prevent Reverse Power Flow Based on Neuro-Fuzzy Networks for Smart Grid

This paper addresses the energy challenges related to the weak protection of renewable energy from reverse energy flow and expanding access to high-quality energy at the same time. Furthermore, this paper focuses on participation in the global transition to clean and low-carbon energy systems. Moreover, the increased demand for renewable energy seems to likely depend on whether it will be possible to greatly accelerate rates of progress toward increased efficiency, de-carbonization, greater generating diversity and lower pollutant emissions. This paper focuses on the protection of renewable energy technologies because they can be particularly attractive in dispersed areas and therefore, represent an important option for rural areas that lack electrical energy and distribution infrastructure. This paper proposes an improved protection device for a reverse power protection system using a new intelligent decision support system (IDSS). The IDSS is a support system for decision making, which makes extensive use of artificial intelligence (AI) techniques. The new method integrates the powerful specification for neural networks and fuzzy inference systems. The main advantage of this method is that it causes a decrease in the steady state oscillation for the reverse power relay. In addition, the proposed method has the ability to monitor extreme environmental conditions. The generator can be converted into a motor when the steam supply to a turbine is interrupted while the generator is still connected to a grid (or operates in parallel with another generator). As a result, the generator will become a synchronous motor and will actually cause significant mechanical damage. The reverse energy protection device should be included in the generator protection scheme. Smart grids use communication networks with sophisticated algorithms to ensure coordination between protection systems. ZigBee is a newly developed technology that can be used in wireless sensor networks (WSNs) to comply with the IEEE 802.15.4 standard. Low data rates, low power consumption and low cost are key features of ZigBee. The execution of star, tree and mesh topologies as well as support comparison is based on end-to-end delay, throughput, medium access control load in addition to sent and received traffic parameters. The use of star topology obtained a delay of 0.2 s. The simulation results show that this method is superior to the traditional method in terms of speed and steady-state oscillation.

Degradation of Polypropylene Membranes Applied in Membrane Distillation Crystallizer

The studies on the resistance to degradation of capillary polypropylene membranes assembled in a membrane crystallizer were performed. The supersaturation state of salt was achieved by evaporation of water from the NaCl saturated solutions using membrane distillation process. A high feed temperature (363 K) was used in order to enhance the degradation effects and to shorten the test times. Salt crystallization was carried out by the application of batch or fluidized bed crystallizer. A significant membrane scaling was observed regardless of the method of realized crystallization. The SEM-EDS, DSC, and FTIR methods were used for investigations of polypropylene degradation. The salt crystallization onto the membrane surface accelerated polypropylene degradation. Due to a polymer degradation, the presence of carbonyl groups on the membranes’ surface was identified. Besides the changes in the chemical structure a significant mechanical damage of the membranes, mainly caused by the internal scaling, was also found. As a result, the membranes were severely damaged after 150 h of process operation. A high level of salt rejection was maintained despite damage to the external membrane surface.