Polypropylene Materials Research Articles

Polypropylene Crystallinity Reduction through the Synergistic Effects of Cellulose and Silica Formed via Sol-Gel Synthesis.

This study focuses on the development of environmentally sustainable polypropylene (PP)-based composites with the potential for biodegradability by incorporating cellulose and the oligomeric siloxane ES-40. Targeting industrial applications such as fused deposition modeling (FDM) 3D printing, ES-40 was employed as a precursor for the in situ formation of silica particles via hydrolytic polycondensation (HPC). Two HPC approaches were investigated: a preliminary reaction in a mixture of cellulose, ethanol, and water, and a direct reaction within the molten PP matrix. The composites were thoroughly characterized using rotational rheometry, optical microscopy, differential scanning calorimetry, and dynamic mechanical analysis. Both methods resulted in composites with markedly reduced crystallinity and shrinkage compared to neat PP, with the lowest shrinkage observed in blends prepared directly in the extruder. The inclusion of cellulose not only enhances the environmental profile of these composites but also paves the way for the development of PP materials with improved biodegradability, highlighting the potential of this technique for fabricating more amorphous composites from crystalline or semi-crystalline polymers for enhancing the quality and dimensional stability of FDM-printed materials.

Multi‐component coupling synergistic effect of resourced gold tailings on intumescent flame‐retardant polypropylene

AbstractAddressing the challenge of resource utilization of gold tailings. A high performance flame‐retardant fillers (K‐GTF) were prepared from gold tailings (GTF) by coupling and condensation for application to intumescent flame‐retardant polypropylene (PP). K‐GTF enhances the flame‐retardant, thermal stability, smoke suppression and mechanical properties of flame‐retardant PP through synergistic approach. The results show that K‐GTF demonstrates good flame‐retardant synergism, with PP composites containing 3% additive (PP/G3) exhibiting substantial flame‐retardant and smoke suppression characteristics. Notably, PP/G3 boasts a limiting oxygen index (LOI) of 36.1%, which is substantially higher than the 33.6% LOI of the flame‐retardant PP without added K‐GTF (PP/G0). Furthermore, the peak heat release rate (PHRR), peak smoke production rate (PSPR), total heat release rate (THR), and total smoke production (TSP) of PP/G3 were decreased by 32.5%, 26.9%, 31.6%, and 21.5%, respectively, as compared to PP/G0. According to the synergistic mechanism analysis, K‐GTF exerts a multi‐component coupling synergistic effect, which promotes the production of phosphorus‐rich cross‐linking structures in flame‐retardant PP materials during the combustion, thereby promotes the formation of stable, dense and intumescent char to further enhances the flame‐retardant performance of the PP materials. In terms of mechanical effects, the introduction of K‐GTF alleviates the issue of a substantial decline in mechanical properties typically caused by flame retardants in PP materials. This indicates that K‐GTF improves the compatibility between the flame retardants and the PP matrix, thereby enhancing the mechanical properties of the flame‐retardant PP materials.Highlights Successfully synthesis a flame‐retardant synergist (K‐GTF). K‐GTF has good synergistic flame‐retardant effect. K‐GTF substantially enhances char formation and thermal stability of flame‐retardant PP. K‐GTF exerts a multi‐component coupling synergistic effect. K‐GTF enhances the compatibility between the PP matrix and the flame retardants.

In-suit cemented strategy enables intumescent flame retardant transition from hyper-hydrophilic to hydrophobic and aggregation flame retardant effect simultaneously in polypropylene

To meet the stringent requirements of specific high-end manufacturing applications involving flame retardant polypropylene (PP) materials, it's imperative to overcome the inherent superhydrophilicity of intumescent flame retardants (IFR) while simultaneously further enhancing flame retardant efficiency. In addressing this challenge, novel in-situ cemented MVC-IFR microparticles characterized by a microparticle-aggregation effect and hydrophobic structure were successfully synthesized. The micro-aggregated MVC-IFR particles not only bolstered the hydrophobicity and charring flame retardancy of PP composites compared to conventional IFR but also exhibited superior resistance to water erosion. The water contact angle (WCA) of 3MVC-22IFR reached an impressive 159°, whereas the WCA of IFR stood at 0°. Moreover, when MVC-IFR and IFR were incorporated into PP, 3MVC-22IFR/PP displayed a WCA of 108° which was a hydrophobic composite, while 25IFR/PP exhibited a WCA of 81° which was a hydrophilic composite. Notably, the hydrophobic MVC-IFR showcased greater resistance to water exposure than hydrophilic IFR, thereby maintaining its flame retardant efficacy in practical applications. Furthermore, MVC-IFR microparticles with aggregation of acid, carbon, and gas sources, facilitated the charring reactions of different components, thereby enhancing its charring flame retardant effect in PP. Remarkably, 1MVC-24/PP not only attained a UL 94V-0 rating but also achieved a glow wire flammability index (GWFI) of >960 °C, a glow wire ignition temperature (GWIT) of 850 °C, and an LOI value of 28.7 %. In contrast, 25IFR/PP failed to secure a UL 94 rating and exhibited lower GWIT and LOI values. Crucially, the peak heat release rate and total smoke release of 1MVC-24IFR/PP were markedly reduced by 76 % and 41 %, respectively, compared with those of neat PP. In summary, this study presented a novel design concept and rules for flame retardant morphology, to find a way for the development of polyolefin materials boasting both high hydrophobicity and superior flame retardancy.

Automated model discovery for textile structures: The unique mechanical signature of warp knitted fabrics

Textile fabrics have unique mechanical properties, which make them ideal candidates for many engineering and medical applications: They are initially flexible, nonlinearly stiffening, and ultra-anisotropic. Various studies have characterized the response of textile structures to mechanical loading; yet, our understanding of their exceptional properties and functions remains incomplete. Here we integrate biaxial testing and constitutive neural networks to automatically discover the best model and parameters to characterize warp knitted polypropylene fabrics. We use experiments from different mounting orientations, and discover interpretable anisotropic models that perform well during both training and testing. Our study shows that constitutive models for warp knitted fabrics are highly sensitive to an accurate representation of the textile microstructure, and that models with three microstructural directions outperform classical orthotropic models with only two in-plane directions. Strikingly, out of 214=16,384 possible combinations of terms, we consistently discover models with two exponential linear fourth invariant terms that inherently capture the initial flexibility of the virgin mesh and the pronounced nonlinear stiffening as the loops of the mesh tighten. We anticipate that the tools we have developed and prototyped here will generalize naturally to other textile fabrics–woven or knitted, weft knit or warp knit, polymeric or metallic–and, ultimately, will enable the robust discovery of anisotropic constitutive models for a wide variety of textile structures. Beyond discovering constitutive models, we envision to exploit automated model discovery for the generative material design of wearable devices, stretchable electronics, and smart fabrics, as programmable textile metamaterials with tunable properties and functions. Our source code, data, and examples are available at https://github.com/LivingMatterLab/CANN. Statement of significanceTextile structures are rapidly gaining popularity in many biomedical applications including tissue engineering, wound healing, and surgical repair. A precise understanding of their unique mechanical properties is critical to tailor them to their specific functions. Here we integrate mechanical testing and machine learning to automatically discover the best models for knitted polypropylene fabrics. We show that warp knitted fabrics possess a complex symmetry with three distinct microstructural directions. Along these, the behavior is dominated by an exponential linear term that characterize the initial flexibility of the virgin mesh and the nonlinear stiffening as the loops of the fabric tighten. We expect that our technology will generalize naturally to other fabrics and enable the robust discovery of complex anisotropic models for a wide variety of textile structures.

Laboratory Investigation of the Strength Degradation against Ultraviolet Radiation of Geonets for Slope Protection.

Sufficient light and high UV intensity pose significant challenges to the long-term performance of polymeric geonet materials for slope-protection structures. This study investigates strength degradation under the effect of UV radiation; five different types of geonets were selected, which can be categorized as polyamide (PA), polypropylene (PP), and polyethylene (PE) materials. A comprehensive experimental investigation was performed, including tension strength, peer strength, artificially accelerated aging, and SEM tests, to further establish a service life prediction method used for slope-protection design. The results showed that the tension strength, percentage of breaking elongation, and peer strength all depict a descending trend with aging-elapsed time, especially in the early 600 h. The decreasing tendency of these mechanical properties' magnitude differed in the diversity of direction and material type. Significant changes have been generated on the geonet surface after aging; materials with smooth surfaces exhibit a strong ability against strength degradation. Fitting results affirmed the predictive technique as a useful engineering tool for tension strength assessments, offering guidelines for using and designing of geonets for slope-protection structures.

Antiviral respiratory masks with plasma-functionalized polypropylene textiles for optimal adsorption of antiviral substance

During the COVID-19 pandemic, face masks were the first line of defense against the spread of infection. However, infectious viruses may remain on medical textiles, potentially serving as an additional source of infection. Due to their chemical inertness, many textiles cannot be enhanced with antiviral functionalities. Through treatment with low-pressure gaseous plasma, we have activated the surface of a medical-grade melt-blown, non-woven polypropylene textile so that it can absorb sodium dodecyl sulfate, an antimicrobial surfactant. Within two hours of contact time, the functionalized textile has been able to inactivate over 7 log10 PFU mL−1 of bacteriophage phi6, a surrogate of enveloped viruses such as SARS-CoV-2, and it has retained its antiviral properties for over 100 days. The functionalized material has not disrupted facial mask filtration efficiency or breathability. In addition, the in vitro biocompatibility testing in accordance with ISO 10993-5 for testing of medical devices has demonstrated that the selected formulation causes no adverse effects on the mouse fibroblast cell line L-929. With the treatment processes that have been completed within seconds, the method seems to have great potential to produce antiviral textiles against future outbreaks.

A study of the seismic resistance performance of strengthened masonry walls using polypropylene mesh-composite on the surface

To investigate the seismic performance of masonry walls in village buildings strengthened with polypropylene mesh materials on the surface, five reduced-scale masonry walls were designed for low-cyclic reversed loading tests. The research observed the failure processes and characteristic forms of masonry walls, conducting a comparative analysis of the hysteresis curves and energy dissipation of the walls. Then, ABAQUS finite element software was used to simulate the performance of the strengthened walls to analyze the damage mode of these walls. The results indicated that under compression-shear loading, unreinforced masonry walls experienced shear failure along horizontal mortar joints, exhibiting lower shear load, lateral stiffness, and ductility. The reinforced walls with polypropylene mesh-composite effectively delayed and mitigated the failure. Weak zones in the wall gradually extended from the structural sides towards the central core area. Ultimately, after the reinforcement material had fully engaged, delamination failure occurred, leading to the formation of "X" or "Y" shaped through cracks. After reinforcement with single-side polypropylene materials, the load-bearing capacity of the wall increased by 165 % compared to the unreinforced wall. The ductility is improved compared to the unreinforced wall, whereas the initial stiffness increased by 133 %. Upon reinforcement with double-sided materials, the wall's load-bearing capacity surged by 180 %. The initial stiffness climbed to 171.3 %. The finite element analysis results closely aligned with the experimental data, suggesting that reinforcing the surface with polypropylene mesh-composite cement mortar significantly bolstered the wall's shear strength and deformation capabilities. This method effectively strengthens the seismic resistance of masonry structures.

Morphological Changes in Tissue When Using Polypropylene Implants with Adsorbed Multipotent Stromal Cells in Experiment.

The subcutaneous tissue of rats after implantation of polypropylene materials with adsorbed bone marrow-derived mesenchymal multipotent stromal cells (MMSCs) was studied using light microscopy. Inflammation in response to implantation was mild, and the foreign material was encapsulated into a thin strip of dense fibrous connective tissue with multinucleated macrophages. By 1 year after introduction of the monofilament and 6 and 12 months after implantation of the mesh product, some threads were deformed, broken, and had sharp edges. Small fragments of foreign material appeared in the adjacent tissues surrounded by their own relatively thick acellular capsule. As a result of preliminary adsorption of MMSCs on polypropylene, the thickness of the connective tissue capsule decreased, its vascularization increased, and the severity of inflammatory infiltration decreased. However, all effects of MMSCs adsorption in rats were transient and disappeared within 1 week.

FORMULATION AND EVALUATION COMBINATION OF CARBOPOL/HPMC POLYMER GELS CONTAINING OFLOXACIN FOR OCULAR DRUG DELIVERY SYSTEM

The current research focuses on assessing hydrochloride/HPMC polyethylene blends for uveitis drug delivery. Processes involving polypropylene (PP) matrices have shown similar behavior to solid lipid nanoparticles, with fluid sub-assemblies playing a larger role. Nanoemulsions, with long-chain structures, link drug dispersibility and rheology. The correct combination of polymer matrices is essential for designing an effective ocular drug delivery system.Further studies suggest that polypropylene enhances self-organization, while HPMC K100 improves drug dissolution and viscosity, particularly in formulations involving narcotics. A blend of three polymers has demonstrated effects on drug dissolution, dispersibility, and viscosity.Nanoemulsion-based formulations have shown the best results for drug dissolution and decent rheological properties. Cultured cell investigations indicate that higher levels of specific plastics improve dosage forms. Overall, this research emphasizes the importance of polymer selection and formulation in optimizing drug delivery for uveitis treatment.

ZnO nanolayer on polypropylene fabrics: a highly effective antimicrobial coating against pathogenic bioaerosols

Abstract Antimicrobial coatings offer a promising solution for enhancing the efficacy of materials used to fabricate protective equipment for healthcare personnel. Given the rapid spread of respiratory diseases caused by pathogenic bioaerosols, our study delves into probing the antimicrobial properties of a sputtered ZnO nanolayer deposited onto polypropylene fabrics earmarked for the production of respiratory protective gear such as facemasks. A comprehensive methodology was developed to assess the immediate antimicrobial effect of the zinc oxide nanolayer against bioaerosols laden with four DNA or RNA viral surrogates and eight aerobic and anaerobic bacterial species. Additionally, its antimicrobial efficacy was measured over time across contact durations ranging from 0.5 to 24 h. The ZnO nanolayer exhibited an immediate reduction in infectivity of approximately 40% for RNA viruses, whereas only an 11% reduction was noted for the DNA virus. Remarkably, the infectivity of RNA viruses was totally eradicated after 12 h of contact with the ZnO nanolayer. In the case of anaerobic bacteria-laden bioaerosols, inhibition ratios ranged from 58% to 97% across various anaerobic strains, while aerobic bacteria aerosols demonstrated inhibition ranging from 26% to 74%. Notably, after 24 h of direct contact between bacteria and ZnO nanolayer, a substantial viability inhibition of most strains (80%–90%) was achieved. These findings underscore the potential of ZnO nanolayer for diverse biomedical purposes, encompassing personal protective equipment and other applications such as air purification systems.

Polypropylene vs. stainless-steel wire suture: short-term recurrence rate after shouldice primary inguinal hernia repair, a non-inferior analysis among 1120 patients. A case-control study.

Polypropylene material is commonly used for posterior wall reconstruction in hernia repair, in contrast with the classically described stainless-steel wire used at Shouldice Hospital. This study was conducted to evaluate possible differences in Shouldice Repair outcomes using polypropylene or stainless-steel wire sutures. A prospective follow-up of consecutive patients who underwent elective unilateral Shouldice primary inguinal hernia repair at Shouldice Hospital between December 6, 2021, and September 1, 2022, was conducted. Data was collected from follow-up telephone calls as well as manually reviewing patient's charts. The primary objective was to determine whether the use of polypropylene was non-inferior to the use of stainless-steel wire, regarding the recurrence rate reported by the patients with a minimum follow-up of 1year after Shouldice primary inguinal hernia repair. A total of 1120 patients were contacted by telephone (polypropylene: 560; stainless-steel wire: 560). The median follow-up period was 16months (interquartile range: 15-18). In 22 (1.96%) cases a surgical site infection was diagnosed. There was a total of 18 recurrences reported by the patients (1.6%). There was no statistical difference between the groups (polypropylene: 7 (1.25%) vs. stainless steel wire: 11 (1.96%), p > 0.05) for the recurrence rate. The use of polypropylene is non-inferior to the use of stainless-steel wire regarding recurrence rate at a median follow-up period of 16months after elective unilateral Shouldice primary inguinal hernia repair. This finding may encourage other centers where stainless-steel wire is not easily available to perform the Shouldice Repair.

Study of Leachable Compounds in Hospital Pharmacy-Compounded Prefilled Syringes, Infusion Bags and Vials

Hospital pharmacy compoundings are crucial for maintaining patient care. They are time- and cost-effective in hospital pharmacy settings because they prevent waste, preparation errors, dosage errors, microbial contamination and breakage due to handling. Unfortunately, the drawbacks of hospital pharmacy compounding include the selection of inappropriate medical devices (MDs) for long-term storage, which could directly impact patients.In this study, three important hospital pharmaceutical compoundings, vancomycin in prefilled syringes (PFSs) made of polypropylene (PP) material, paediatric parenteral nutrition (PN) in ethylene vinyl acetate (EVA) bags and diluted insulin in cyclic olefin copolymer (COC) vials, were selected for leachate study and risk assessment. These compounds were studied via a semiquantitative screening approach by means of an ultrahigh-performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS) with postcolumn infusion and an in-house built database. 17 leachable compounds for the PFS, 25 for the PN, and 10 for the vial were identified, and their concentrations were estimated for toxicological assessments.In conclusion, all MDs used in hospital pharmacy compoundings were observed suitable thanks to risk assessments. However, suitable MDs recommended for long-term storage would remain with polymers like COC, for higher safety when exposed to frail and vulnerable patients like neonates and infants.

Study of Large Strain OFDR Sensor Based on Inclined Transfer Structure

In the fields of structural health monitoring, civil engineering safety monitoring, aerospace and other fields, the key challenge is to increase the range of strain measurements to solve with the information monitoring of large strains. Reducing the strain sensitivity of the sensor is an important way to solve the problem of small sensor ranges. In this paper, the inclined transfer structure is proposed to achieve large strain distributed optical fiber sensing. When the fiber is axially stretched directly to fracture, the inclined transfer structure is used to increase the strain measurement range of the system. The theoretical relationship between the strain monitored by single mode fiber sensors and the matrix strain is established. It is experimentally verified that the inclined transfer structure using polypropylene material as the matrix achieves the strain measurement from 36667[Formula: see text][Formula: see text] at sensing spatial resolution of 8[Formula: see text]mm, 10[Formula: see text]nm wavelength tuning range of the laser source and [Formula: see text] inclined angle, obtaining a good linear fit of more than 0.99. One hour stability of less than 11[Formula: see text]pm is obtained, corresponding to the strain of 9[Formula: see text][Formula: see text].

Characterization, processing, and modeling of industrial recycled polyolefins

AbstractThis study aims to establish a systematic approach for characterizing recycled polyolefins of unknown composition, with a specific focus on predicting their performance in film extrusion. We explore various characterization techniques, including differential scanning calorimetry (DSC), Fourier‐transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and rheometry to assess their effectiveness in identifying the polyethylene (PE) fractions within polypropylene (PP) recyclates. By integrating experimental data with modeling techniques, we aim to provide insights into the predictive capabilities of these techniques in determining processing behaviors. The research highlights the superior fidelity of DSC in predicting the relative fraction and type of PE in a PP recyclate. FTIR is also identified as a high‐fidelity approach, albeit requiring application‐specific calibration. TGA, capillary, and oscillatory rheometry are recognized for their ability to distinguish between grades of recycled polyolefins but provide aggregate behaviors rather than detailed constituent information. 3D flow simulation of the cast film extrusion investigated the effect of the viscosity characterization method, non‐isothermal assumption, and process settings but could not fully replicate the observed variations in the cast film processing of two industrial polyolefins with similar melt flow rates and viscosity behaviors. This underscores the practical challenge of predicting processing issues prior to actual processing, necessitating reliance on reliable instrumentation suites and human expertise for diagnosing and remedying variations.Highlights Two industrial recycled polypropylene materials having similar melt flow rates exhibit drastically different cast film processing behaviors. DSC and FTIR provide reasonable approaches for identifying constituent materials. Modeling of the melt viscosities characterized by capillary and parallel plate rheology suggests that viscosity variations relative to the power‐law behavior assumed in the coat hanger die design is a predominant driver of cast film instabilities.

Improvement of ankle foot orthotics fabrication using 3D printing method

Orthotics are the body support devices used for correction, immobilization, fixation, and prevention of paralysis. The greatest number of orthotics utilized by people suffering from plantarflexion and dorsiflexion disability, especially in Indonesia, is ankle foot orthotic (AFO). However, the duration associated with fabricating AFO through conventional methods is considered time-consuming. This paper aims to fabricate ankle foot orthotics (AFO) using innovative combinations of 3D scanning and 3D printing. The method begins with 3D scanning of the patient’s lower limb using photogrammetry (3DF Zephyr). The design is generated and adjusted, afterwards, the orthotic prototype is produced by fused deposition modeling (FDM) 3D printing using polypropylene (PP) material. This choice is attributed to the material's advantages, such as being lightweight, rigid, durable, and cost-effective. The 3D mesh model scanned using 3DF Zephyr shows good quality and more precise results. In addition, the prototype produced using 3D printing was tested by walking based on normal gait analysis’s angle of foot and calf measurement, which shows a maximum range of motion (ROM) of 16.1˚. The proposed methods of fabricating orthotic prototypes can successfully reduce the processing time by approximately 70% compared to the conventional method.

Triaxiality and Plastic-Strain-Dependent Proposed PEAK Parameter for Predicting Crack Formation in Polypropylene Polymer Reservoir Subjected to Pressure Load.

This article raises the topic of the critical examination of polypropylene, a key polymeric material, and its extensive application within the automotive industry, particularly focusing on the manufacturing of brake fluid reservoirs. This study aims to enhance the understanding of polypropylene's behavior under mechanical stresses through a series of laboratory destruction tests and numerical simulations, emphasizing the finite element method (FEM). A novel aspect of this research is the introduction of the PEAK parameter, a groundbreaking approach designed to assess the material's resilience against varying states of strain, known as triaxiality. This parameter facilitates the identification of critical areas prone to crack initiation, thereby enabling the optimization of component design with a minimized safety margin, which is crucial for cost-effective production. The methodology involves conducting burst tests to locate crack initiation sites, followed by FEM simulations to determine the PEAK threshold value for the Sabic 83MF10 polypropylene material. The study successfully validates the predictive capability of the PEAK parameter, demonstrating a high correlation between simulated results and actual laboratory tests. This validation underscores the potential of the PEAK parameter as a predictive tool for enhancing the reliability and safety of polypropylene automotive components. The research presented in this article contributes significantly to the field of material science and engineering by providing a deeper insight into the mechanical behavior of polypropylene and introducing an effective tool for predicting crack initiation in automotive components. The findings hold promise for advancing the design and manufacturing processes in the automotive industry, with potential applications extending to other sectors.

Antimicrobial Face Masks and Mask Covers with a Salt-Coated Stacked Spunbond Polypropylene Fabric: Effective Inactivation of Resilient Pathogens and Prevention of Contact Transmission.

In response to the ongoing threat posed by respiratory diseases, ensuring effective transmission protection is crucial for public health. To address the drawbacks of single-use face masks/respirators, which can be a potential source of contact-based transmission, we have designed an antimicrobial face mask and mask covering utilizing a stack of salt-coated spunbond (SB) fabric. This fabric acts as an outer layer for the face mask and as a covering over a conventional mask, respectively. We evaluated the universal antimicrobial performance of the salt-coated three-stacked SB fabric against enveloped/nonenveloped viruses and spore-forming/nonspore-forming bacteria. The distinctive pathogen inactivation efficiency was confirmed, including resistant pathogens such as human rhinovirus and Clostridium difficile. In addition, we tested other filter attributes, such as filtration efficiency and breathability, to determine the optimal layer for salt coating and its effects on performance. Our findings revealed that the outer layer of a conventional face mask plays a crucial role in contact transmission through contaminated face masks and respirators. Through contact transmission experiments using droplets involving three types of contaminants (fluorescent dyes, bacteria, and viruses), the salt-coated stacked SB fabric demonstrated a superior effect in preventing contact transmission compared to SB or meltblown polypropylene fabrics─an issue challenging to existing masks. Our results demonstrate that the use of salt-coated stacked SB fabrics as (i) the outer layer of a mask and (ii) a mask cover over a mask enhances overall filter performance against infectious droplets, achieving high pathogen inactivation and low contact-based transmission while maintaining breathability.

Characterizing eco-composite boards with non-woven polypropylene from disposable face masks and bamboo reinforcement

This study investigates the development of eco-composite panels using treated and untreated nonwoven polypropylene (PP) extracted from disposable medical face masks, reinforced with bamboo particles. Treated PP underwent a washing process with detergent. Panels were fabricated with varying PP-to-bamboo particle ratios of 100:0, 75:25, and 50:50. Fourier-transform infrared (FT-IR) spectroscopy analysis indicated minimal impact of washing on the intrinsic properties of the PP material, as confirmed by thermogravimetric analysis (TGA). Both analyses showed similar intensities of functional groups and thermal trends in treated and untreated recycled PP (rPP) samples. Energy-dispersive X-ray spectroscopy (EDX) confirmed the uniform integration of bamboo particles within the PP matrix by detecting silicon and potassium elements. Chemical interactions between bamboo fibres and the PP matrix were also evident in the form of reduced peak intensities in FT-IR spectra. Despite these interactions, limited adhesion between bamboo fibres and the PP matrix led to reduced stability and mechanical strength in the eco-composite panels. A direct correlation was observed between board thickness and the proportion of bamboo particles, with the 50:50 formulation showing the greatest thickness. Conversely, board strength decreased as bamboo particle concentration increased due to weak interfacial adhesion. Notably, panels made from treated rPP exhibited superior mechanical properties compared to those from untreated rPP, achieving a modulus of rupture (MOR) of 36.259 MPa and a modulus of elasticity (MOE) of 2048.215 MPa. These findings underscore the potential of utilizing nonwoven PP from disposable medical face masks, reinforced with bamboo fibre particles, to create eco-composite materials with enhanced sustainability and mechanical properties.

Microstructural and antibacterial properties of copper oxide deposited on polypropylene fabric by magnetron sputtering

In this study, antibacterial coatings composed of copper and its oxides were deposited on polypropylene (PP) fabrics using magnetron sputtering. The coatings were deposited under varying oxygen partial pressures to facilitate the formation of cupric and cuprous oxides in different quantities. The formation of these oxides was confirmed by the surface morphology (Scanning Electron Microscopy [SEM]) and X-Ray Diffraction (XRD) analysis. Additionally, the antibacterial properties of the coated fabrics were evaluated. The results show that both copper and copper oxides achieved a 4-log reduction in gram-positive bacteria. Inductively Coupled Plasma Mass Spectroscopy (ICPMS) results indicated that the release of copper atoms into water from the coated fabrics was minimal, even after 30 days of immersion.

Application of Sodium silicate as a halogen-free flame-retardant and evaluate its effectiveness on the flame-retardancy of Polypropylene fabric

A halogen-free flame-retardant was synthesized using Silica gel and Sodium hydroxide within the scope of the study. The Polypropylene (PP) fabric was treated with the synthesized Sodium Silicate to investigate its thermal behaviour. The limiting oxygen index (LOI) value of the Polypropylene fabrics dramatically increased after finishing with Sodium silicate and the 50.4% noteworthy LOI value was achieved. The Sodium silicate-treated PP fabrics exhibited a 30.1% LOI value even after washing, compared to the neat PP LOI value which was reported to be 16.4%. The surface modification of the Polypropylene fabric following the plasma treatment was evaluated by elemental mapping, surface topography images, and contact angle measurements and the homogeneity of the Sodium silicate coating was evaluated by Scanning electron microscopy.