Polypropylene Plastic Research Articles

Studies on durability, thermal and morphological property with partial replacement of single use waste plastic and complete recycled aggregate in eco-friendly self-compacting concrete

This study focuses on creating an eco-friendly self-compacting concrete (EF-SCC) by recycling waste materials like plastic and construction debris. The researchers collected High-Density Polyethylene (HDPE) and Polypropylene (PP) plastics, cleaned and shredded them, then used them to partially replace fine sand at different levels, from 5% up to 20%. They also replaced all the traditional coarse rock aggregate with recycled materials from construction waste. The concrete’s flow and ease of pouring (workability) were tested, and it was found that mixes with recycled aggregates flowed faster, with the best result being a 6-second flow time when using 10% HDPE. Durability tests were done by exposing the concrete to acid and sulphate attacks over several weeks, showing that the recycled concrete with plastics held up well, with only minor weight loss after 56 days in acid. Thermal tests showed that adding plastic lowered the concrete’s heat conductivity by 30-35%, making it better at insulating. Microscopic analysis showed that the plastic was well integrated with the cement mixture, and chemical tests confirmed there were no harmful reactions between the plastic and the cement. Overall, the study suggests that EF-SCC made with recycled aggregates and plastic waste can keep key properties needed for construction, making it a promising, sustainable building material

Analyzing and examining the impact of various fiber types on the mechanical and functional characteristics of UHPC

In this research, we compared the performance and mechanical properties of (UHPC) produced with varying percentages of waste and recycled fibers, including polypropylene plastic (plastic sack fibers) (PP), polyethylene terephthalate (PET), date palm fibers (DP), Monterey pine tree fibers (MP), human hair (HH), and aluminum (from metal cans) (AF). This was done in relation to a control sample of UHPC (WC). The study investigated the effects of different percentages of these fibers (0, 0.5, 1, 1.5, and 2 percent by weight of cement) with a length of 3 cm in self-compacting concrete. We conducted tests on fresh concrete, including Slump Flow, J-Ring, V-Funnel, L-Box, and U-Box, as well as tests on hardened concrete, such as compressive strength, tensile strength, permeability, crack width control, thermal cracking, Schmidt hammer tests, and ultrasonic pulse velocity. The results indicated that increasing the percentage of fibers (PP, PET, DP, AF, MP, and HH) in UHPC enhances tensile strength, reduces permeability, and increases compressive strength. Additionally, under the influence of temperature, a decrease in both the depth and length of cracks was observed in the concrete slabs. Notably, the inclusion of 2% human hair fibers (HH) in UHPC resulted in superior tensile strength, reduced permeability, and minimized both the length and depth of cracks compared to other fiber types. Conversely, the addition of 2% aluminum fibers (AF) led to a reduction in tensile strength, an increase in permeability, and an increase in both the length and depth of cracks. This research demonstrated that, in terms of mechanical and functional properties, human hair fibers provided better results in UHPC across all tests conducted, significantly enhancing the longevity of the structure.

Designing and Evaluating a Portable UV-LED Vane Trap to Expedite Arthropod Biodiversity Discovery.

A novel design of a portable funnel light trap (PFLT) was presented for collecting insects in ecological studies. The trap consists of a compact plastic box equipped with a light source and power source, along with two plastic polypropylene interception vanes. The PFLT costs 18.3 USD per unit and weighs approximately 300 g. A maximum of six PFLT units can be packed in one medium-sized backpack (32 cm × 45 cm × 15 cm, 20 L), making it easier to set up multiple units in remote areas wherein biodiversity research is needed. The low cost and weight of the trap also allows for large-scale deployment. The design is customizable and can be easily manufactured to fit various research needs. To validate the PFLT's efficacy in collecting insects across different habitat types, a series of field experiments were conducted in South Korea and Laos, where 37 trials were carried out. The PFLT successfully collected 7497 insects without experiencing battery issues or damage by rain or wind. Insect compositions and abundances differed across the three sampled habitat types: forests, grasslands, and watersides. This new FLT trap is an important tool for studying and protecting insect biodiversity, particularly in areas wherein conventional light traps cannot be deployed.

Machine learning model and input batch management tool for the composition of new recycled polypropylene plastic material with reduced variability in target properties

Reducing the variability of recycled plastic materials is a prerequisite to encourage the safe substitution of virgin materials in new components manufacturing, hence promoting the circular economy (CE) to achieve the recyclability objectives set by the European Commission. To increase the use of recycled materials in some industrial sectors, such as in automotive, it is necessary to control and reduce their batch-to-batch variability to ensure that the required properties lay in reasonable ranges. In this work, through the analysis of the accumulated historical data from a recycling company, and with the help of machine learning (ML) techniques, a model is developed that predicts key material properties (melt flow index, ash content, Izod impact strength and percentage of shrinkage) in a mixture of recycled polypropylene (PP) batches from different sources. The model is validated correlating predictions with experimental measurements over new batch mixtures compounded on purpose. A batch management algorithm considers the entry flow of material batches received in the recycling company and proposes mixtures for the production of new recycled batches with reduced variability and controllable target properties. Furthermore, it proposes solutions for batch management to maximize the production output while maintaining the properties of the recycled material within target variability limits.

Revealing the characteristics of biofilms on different polypropylene plastic products: Comparison between disposable masks and takeaway boxes

The increasingly severe plastic pollution issue was intensified by the enormous plastic emissions into ecosystems during the Covid-19 pandemic. Plastic wastes entering the environment were swiftly exposed to microorganisms and colonized by biofilms, and the plastic-biofilm combined effects further influenced the ecosystem. However, the non-woven structure of disposable masks discarded carelessly during the COVID-19 pandemic was different from those of plastics with flat surface. To reveal the potential effects of plastic structure on colonized biofilms, white disposable surgical masks (DM) and transparent takeaway boxes (TB), both made of polyethylene, were selected for the incubation of organic conditioning films and biofilms. The results indicated that the non-woven structure of disposable mask was destroyed by the influence of water infiltration and biofilm colonization. The influence of surface structure on conditioning films led to a relatively higher proportion of tryptophan-like substances on DM than those on TB samples. Therefore, biofilms with significantly higher microbial biomass and carbon metabolic capacity were formed on DM than those on TB samples owing to the combined effects of their differences in surface structure and conditioning films. Moreover, abundant functional microorganisms associated with stress tolerance, carbon metabolism and biofilm formation were observed in biofilms on disposable mask. Combining with the results of partial least squares regression analysis, the selective colonization of functional microorganisms on disposable masks with uneven surface longitudinal fluctuation was revealed. Although the predicted functions of biofilms on disposable masks and takeaway boxes showed more similarity to each other than to those of free-living aquatic microorganisms owing to the existence of the plastisphere, biofilms on disposable masks may potentially trigger environmental risks different from those of takeaway boxes by unique carbon metabolism and abundant biomass.

Experimental analysis on products distribution, characterization and mechanism of waste polypropylene (PP) and polyethylene terephthalate (PET) degradation in sub-/supercritical water

Supercritical water (SCW) treatment of plastics is a clean technology in the ‘waste-to-energy’ path. In this work, PP and PET plastics were processed by sub-/supercritical water. The results showed that temperature was the most important factor of the PP and PET degradation. The influence of factors on the degradation of plastics follows the following order: temperature > residence time > plastic/water ratio. These factors influenced the yield of gas products by promoting or inhibiting various reactions (such as reverse water gas shift reaction, methylation reaction, and Fischer-Tropsch synthesis reaction). Besides, the composition of liquid oil was also analyzed. The main composition of the liquid oil produced by PET was benzoic acid and acetaldehyde, which were generated from the decarboxylation of terephthalic acid (TPA) and dehydration reaction of ethylene glycol (EG). The liquid oil from PP was mainly long-chain olefins, long-chain alkanes, cycloalkanes, etc., which were formed by the interaction of various methyl, alkyl, hydroxyl, and other free radicals. This study could build fundamental theories of plastic mixture treatment.

Microwave-assisted upcycling of plastic waste to high-performance carbon anode for lithium-ion batteries

The increasing demand for high-performance lithium-ion batteries (LIBs) has emphasized the need for affordable and sustainable materials, prompting the exploration of waste upcycling to address global sustainability challenges. In this study, we efficiently converted polypropylene (PP) plastic waste from used centrifuge tubes into activated polypropylene carbon (APC) using microwave-assisted pyrolysis. The synthesis of APC was optimized using response surface methodology/central composite design (RSM/CCD). Based on the RSM results, the optimal conditions for PP plastic conversion into carbon were determined as follows: HNO3 concentration of 3.5 M, microwave temperature of 230 °C, and holding time of 25 min. Under these conditions, the obtained intensity ratio of Id/Ig in PP carbon was 0.681 ± 0.013, with an error of 6.81 ± 0.013 % between predicted and actual values. The physicochemical studies, including FESEM-EDX, XRD, and Raman spectroscopy, confirmed the successful synthesis of APC samples. The APC 800 material exhibited a well-organized three-dimensional structure characterized by large pores and mesopores, enabling fast ion transport in the electrode. As a result, the APC 800 electrode demonstrated an initial discharge capacity of 381.0 mAh/g, an improved initial coulombic efficiency of 85.1%, and excellent cycling stability after 100 cycles. Notably, the APC 800 electrode displayed remarkable rate performance, showing a reversible capacity of 355.1 mAh/g when the current density was reset to 0.2 A/g, highlighting its high electrochemical reversibility. The outstanding characteristics of APC 800 as an anode electrode material for high-performance lithium-ion batteries suggest a promising future for its application in the field.

Aging and characterization of disposable polypropylene plastic cups based microplastics and its adsorption for methylene blue

Microplastics (MPs) as emerging pollutants are of increasing concern, due to their ubiquitous, uncertain, and complex environmental impacts. Different from the standard spherical MPs without additives, here polypropylene microplastics (PP-MPs) in flake derived from the disposable plastic cup in food-grade in daily life were studied. The characterization of PP-MPs demonstrated that the carbonyl index represented the aging degree was enhanced from 0.26 significantly to 0.82 after 10 days, and the aging process fitted well with pseudo-first-order kinetic. Moreover, the crystallinity degree, polarity and surface negative charges were enhanced, while the hydrophobicity was decreased. The adsorption behavior of PP-MPs toward methylene blue (MB), and the impacts of various pHs, salinities, and humic acid in aquatic environments were also explored. The pseudo-second-order kinetic, Henry and Sips isotherm models provided a good correlation with the experimental data, indicating that the rate-limiting step was closely related with the complex surface adsorption, and the hydrophobic partitioning, polar interaction, electrostatic attraction, and hydrogen bonding were possibly involved in the adsorption. These exhaustive experiments aim to provide a theoretical basis for assessing and better understanding the environmental behavior of disposable PP plastic cups in nature.

Pendugaan umur simpan kerupuk sagu goreng dengan pendekatan kurva isoterm sorpsi air [Shelf-life estimation of fried sago crackers by water sorption isotherm curve approach

Fried sago crackers are dry local foods easily damaged by moisture during storage. To increase economic value and open commercialization opportunities, a study aimed to estimate the shelf life of white and red fried sago crackers using an acceleration method based on the water sorption isotherm curve. Estimating the shelf life was carried out by storing crackers in several modified jars containing different saturated salt solutions. Calculating the moisture permeability constant of polyethylene and polypropylene packaging was also carried out to support the necessary data. The results showed that sago crackers packaged in polypropylene had a longer shelf life than polyethylene plastic. The white sago crackers with polypropylene plastic had a shelf life of 19.89-69.83 days at 70-90% RH, while polyethylene was 12.02-42.21 days at 70-90% RH with 0.0434 g H2O.g solid-1 critical water content. The red sago crackers with polypropylene plastic had a shelf life of 18.26-69.93 days at 70-90% RH, while polyethylene was 11.04-42.27 days at 70-90% RH with a critical water content of 0.0455 g H2O.g solid-1. The chosen model for the water sorption isotherm curve was Hasley and GAB, with equation log (ln (1/aw)=-1.82-1.31 log Me for white sago fried crackers and Me=(0.5157aw)/(1-0.9632aw)(1+15.578aw) for red sago fried crackers, respectively. Fried sago crackers in polypropylene plastic packaging have the potential to be developed as local food products with a longer shelf life.

The programmed sequence-based oxygenase screening for polypropylene degradation

Enzymatic degradation of plastic is an effective means of plastic recycling and pollution control. However, the strong chemical inertness of polypropylene plastic (PP) severely impedes its oxidative cleavage, making it resistant to degradation. In this study, based on sequence screening of Hidden Markov Model (HMM), a dioxygenase (HIS1) was identified and characterized to be effective in PP oxidation. Various kinds of PP products, including plastic films, microplastics, and disposable water cups or bags, were HIS1-degraded with cracks and holes on the surface. The hydrophobic binding was the primary force driving oxidative degradation in the specific cavity of HIS1. The discovery of HIS1 achieved a zero breakthrough in PP biodegradation, providing a promising candidate for the selection and evolution of degrading enzymes.

Deterioration of single-use biodegradable plastics in high-humidity air and freshwaters over one year: Significant disparities in surface physicochemical characteristics and degradation rates

More single-use plastics are accumulating in the environment, and likewise biodegradable plastics (BPs), which are being vigorously promoted, cannot escape the fate. Currently, studies on the actual degradation of BPs in open-air and freshwaters are underrepresented despite they are potentially headmost leakage and contamination sites for disposable BPs. Herein, we compared the degradation behavior of six BP materials and non-degradable polypropylene (PP) plastics over a 1-year in situ suspension in the high-humidity air, a eutrophic river, and an oligotrophic lake. Moreover, a 3-months laboratory incubation was performed to detect the release of dissolved organic carbon (DOC) from BPs. In both air and freshwaters, poly(p-dioxanone) (PPDO) degraded significantly while PP and polylactic acid (PLA) showed no signs of degradation. The average degradation rates of three poly(butylene adipate-co-terephthalate) (PBAT)-based films varied: 100% in river, 55% in lake, and 10% in air. In addition to PLA, surface chemical groups, hydrophilicity, and thermal stability of BPs changed, and microplastics were found on their surfaces. Correspondingly, BPs with faster degradation rates released relatively higher amounts of DOC. Environmental microbial and chemical characteristics may contribute to differences in BP degradation besides polymer specificity. Altogether, our results indicate the need for appropriate monitoring of BPs.

Pyrolysis of polypropylene plastic waste: An analysis of oil quantity, density, viscosity, and calorific value

Owing to the inability of the material to biodegrade, the handling of plastic waste presents a considerable challenge. Pyrolysis is a plastic waste management method that solves the problem of plastic waste volume through chemical recycling. This study aims to assess the quantity and quality of the density, viscosity, and calorific value of oil produced from the pyrolysis of polypropylene (PP) plastic and compare it to commercial oils. This research used 15 kg of PP plastic waste. The pyrolysis process was conducted at temperatures ranging from to 250-350°C. The amount of extracted PP pyrolysis oil was 12.730 L. The oil derived from the pyrolysis of PP plastic had a density of 811 kg/m3 at 250°C and 782 kg/m3 at 350°C. The PP plastic had the highest viscosity at 250°C, and 2.02cP, and the lowest viscosity at 350°C, and 0.86cP. The oil from PP plastic pyrolysis had a maximum calorific value of 10, 870 kcal/g at 350°C and the lowest calorific value of 10, 386 kcal/g at 250°C. Compared with open burning, the pyrolysis treatment of plastic waste can reduce greenhouse gas emissions by 99 percent. However, the energy required for the pyrolysis process is 400 times greater than that provided by the pyrolysis oil product.

The Use of Polymeric Materials of Polyethylene Terephthalate (PET) and Polypropylene (PP) as the media of Anaerobic-aerobic bioreactors in treating wastewater from the tofu industry

Small-scale businesses often dominate the tofu sector in Makassar City, preventing any prior wastewater management. While tofu is typically produced on a household scale, the wastewater treatment process is limited due to the need for suitable technology and high prices. Therefore, it is necessary to conduct this research to obtain tofu wastewater results that meet environmental discharge standards and develop a straightforward and affordable waste treatment concept. A laboratory scale with an experimental method is used in this study, where the test parameters used were BOD, COD, and TSS using two types of biofilter media, namely mineral water bottle media made of PET plastic and plastic straw media made of PP plastic with variations in observation time of 24 hours for six days. The results presented that the efficiency of the average removal in plastic-media reactors with mineral water bottles reduced BOD by 88.30%, COD by 88.97%, and TSS by 79.13%. The straw-based plastic reactor reduced BOD by 86.74%, COD by 85.41%, and TSS by 67.03%. The effectiveness value obtained shows that biofilter media made from plastic mineral bottles (PET) produces better effectiveness in removing BOD, COD, and TSS than biofilter media made from plastic straws (PP).

Selective thermal recycling for graphene growth on natural substrates: A comparative study on life cycle assessment, energy consumption, and mechanical performance in recompounding

AbstractManufacturing of carbon‐based materials from waste thermoplastics is a keystone to reduce adverse environmental impacts. There are numerous attempts for sustainable graphene manufacturing from various waste sources by thermal treatment but there is no clear distinction on the effective conversion process by addressing reliable CO2 footprints. This study provides a comprehensive benchmarking study on the conversion of waste polypropylene plastics coming from yogurt containers into graphene on the substrate of talc by applying two upcycling techniques of catalytic carbonization (CC) and flash pyrolysis (FP) by comparing energy and speed of the processes and a dimensional stability and physical characteristics of the produced graphene substances by adopting a comparative life cycle assessment. FP led to the sphericalization of graphenes due to fast dehydration, cross‐linking, and carbonization of aromatic structures. On the other hand, gradual heating in CC caused the formation of tubular‐like graphene structures. In addition, FP became advantageous by resulting in 52% of CO2 emission compared with CC process. On the other hand, graphenes separated from talcs exhibited a remarkable 70% reduction in global warming potential compared with conventional graphene production from graphite. In order to complete the value chain and circularity, the mechanical performance of two different hybrid additives produced by selective thermal recycling in recompounding with copolymer polypropylene was examined, and additives from CC enhanced the flexural and tensile properties two times better than the one from FP. With this study, it becomes possible to compare analysis of graphene growth on natural substrates by exploring life cycle assessment, energy consumption, and mechanical performance with selective thermal recycling and recompounding.

UV Irradiation of Polyethylene Terephthalate and Polypropylene and Detection of Formed Microplastic Particles Down to 1 μm.

The degradation of plastics upon UVC irradiation in aqueous solution and the formation of microplastic (MP) particles were investigated. Polypropylene (PP) and recycled and virgin polyethylene terephthalate (PET) were irradiated with a UV lamp emitting light at 254 nm. Irradiation was performed for 15 and 30 min, respectively, at an intensity of about 0.3 W cm-2 . The formation of MP was studied by Raman spectroscopy. The results showed that MP particles were formed after irradiation and that their number was significantly higher in the recycled PET than in the virgin material. The number of PP MP formed was lower compared to PET and was not significantly different after 15 and 30 min. In addition, ethanol was used as an alternative solvent to investigate how its chemical properties and interactions with UVC irradiation affect the degradation of PET and PP plastics. The use of ethanol and recycled PET resulted in a lower number of MP particles at both irradiation times. When ethanol was used after 30 min of irradiation, significantly more PP MP formed. The different chemical structures of PET and PP combined with the different solvent properties of water and ethanol contribute to the differences in their susceptibility to UVC degradation.

Long-term study of the bacterial colonization of polypropylene microplastics in a freshwater lake by optical and molecular methods

Bacterial colonization and the associated bacterial community on microplastic surfaces in freshwater might alter the physiochemical properties of the plastic surfaces. In our study, a long-term investigation of these potential alterations was performed, as biofilm development needs a more extended period to form, and it could change in connection with the environmental conditions or the location. In this study, our formerly published [56], self-developed plastic colonizer method was used for continuous monitoring of plastic associated bacterial community. The same colonizers, filled with commercially available polypropylene plastic straws cut into less than 5 mm small pieces (microplastic particles), were submerged in a freshwater lake in Hungary (Vácszentlászló), but in this study these sampling tools were kept in the freshwater environment for a much longer period. Time of incubation was fourteen months, started from April 2019 and last until June 2020. Samples from plastic colonizers and a lake water were collected every month (first was taken in May 2019) during this study. The waterborne and polypropylene-associated bacterial communities of these samples were analyzed by Illumina 16S rRNA gene amplicon sequencing. The plastic-associated bacterial community was described at different taxonomic levels. In the first month, the water-associated waterborne community was dominated by Proteobacteria and Cyanobacteria. Proteobacteria followed by Bacteroidetes, and Actinobacteria dominated the polypropylene-associated community. Over time, the bacterial composition on the polypropylene (PP) surface, in terms of phylum level, was altered, eventually becoming distinct from the bacterial community found in the lake water. In addition, Raman microscopy, scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) were used to study the physiochemical changes of the incubated microplastic surfaces due to bacterial colonization. The physical changes were dominant, with the relatively little ageing impact on the chemical composition. Surface morphology and composition of the plastic were studied as they could significantly influence the physical properties of microplastics, the microbiota, and environmental interactions that affect plastisphere colonization. General water analyses of the lake water was also the part of the research, and it was conducted four different time points during the study. Some of the measured components (mostly in August and October of 2019) exceeded the Hungarian governmental threshold for water quality.

Synergistic effects and products yield analyses based on co-pyrolysis of poplar tree and rape stalks with polyethylene terephthalate and polypropylene

In this study, results from co-pyrolysis of poplar tree, rape stalks (biomass) and polyethylene terephthalate, polypropylene (plastics) are reported using thermogravimetric analyzer, Fourier transform infrared spectroscopy and Pyrolyzer-Gas chromatograph/Mass spectrometry. The individual samples, and their mixtures (in 1:1 mass mixture ratios) were investigated to evaluate their co-pyrolysis behavior. TGA results showed the decomposition of agroforestry residues and plastic mixtures having three main stages of moisture evaporation, volatilization, and solid decomposition. The volatilization stage was important in the process. FTIR results showed the presence of poplar tree and rape stalks promoted the pyrolysis of plastics, which also supported the results of TGA. The same absorption bands at the same wavenumbers, indicated the presence of similar chemical functional groups. Py-GC/MS results showed co-pyrolysis of agroforestry residues and PET promoted formation of aromatic and acid while with PP, it promoted hydrocarbons and alcohol at 700 °C.

Removal of Cd2+ and Cr3+ ions from Aqueous Solution by Modified Polypropylene Plastic Waste: Equilibrium Study

Heavy metals pollution of water poses a major environmental challenge due to its antagonistic effects. They are not biodegraded and tend to accumulate in human body to toxic levels linked to some health effects. Therefore, there is need for their removal in water. Technologies that exist such as membrane filtration are limited by their high operation cost. However, adsorption is a cheap, efficient, and easy technique of removal of pollutants from wastewater. There are limited information available on value addition of plastic waste for application as adsorbents. Global production of polypropylene amount to about 56 million metric tons with a large percent of these going to waste. Application of polypropylene plastic waste was explored in this study for remediation of Cd2+ and Cr3+ ions from model solution. This was achieved by first chemically modifying the plastic by use of hydrogen peroxide and hydrochloric acid then applying it for adsorption of Cd2+ and Cr3+ ions. The chemically modified plastic waste was characterized and applied for equilibrium adsorption batch experiments. The images obtained from SEM analysis confirmed availability of pores in the adsorbent which are critical for Cd2+ and Cr3+ ions adsorption. The FTIR results confirmed the attachment of hydroxyl groups on the adsorbent which are vital for removal of heavy metals. Effect of adsorbent dosage, contact time, solution pH and initial metal ion concentration were investigated and the concentration of the resulting filtrate after adsorption determined using ICP-AES. The results from optimization experiments showed that Cd2+ and Cr3+ ions adsorption was optimal at initial metal ion concentration values between 15mg/L and 20mg/L and contact time of 45 mins and 60 mins respectively. Optimum adsorbent mass of 0.1g and optimal pH values between 4.5 and 5.5. Equilibrium experimental results showed adsorption capacities of 7.395mg/g (Cd2+) and 6.225mg/g (Cr3+) for Langmuir isotherm model with R2˃0.99 indicating chemisorption process.

Correlation of mechanical and optical properties of polypropylene plastic waste for application in composite panels

Sustainable plastic waste management systems are needed to reduce environmental pollution impacts as they are non-biodegradable and emit greenhouse gases when burned. This study investigates the feasibility of using recycled polypropylene (PP) from commonly used plastics to process composite panels. The samples were obtained from household plastics with a Resin Identification Code (RIC) of 5. In addition, other common polymer samples were obtained from plastic coffee cups (W) and red basin tubs (R) and moulded using an injection moulding machine. The mechanical strengths of the resultant composites were plotted and compared with the theoretical value of the pure polymer. The ultimate tensile strength of the white cups and the red basin tubs was found to be 36 MPa and 14.55 MPa, while their yield points were 14.45 MPa and 4.55 MPa, respectively. Infrared spectra of the absorption of the samples were obtained using Fourier transform infrared (FTIR) spectroscopy. The band gaps were analysed from Tauc’s plot and were found to be of white cups and the red bath tubs at 3.392 eV and 3.646 eV, respectively. These properties were found to be suitable for recycled plastics to be applied to process value-added panels with no significant adverse influence on material properties.

Fabrication of Polypropylene Nanoplastics Via Thermal Oxidation Reaction for Human Cells Responsiveness Studies.

With the current worldwide increasing use of plastics year by year, nanoplastics (NPs) have become a global threat to environmental and public health concerns. Among plastics, polypropylene (PP) is widely used in industrial and medical applications. Owing to the lack of validated detection methods and standard materials for PP NPs, understanding the impact of PP NPs on the environmental and biological systems is still limited. Here, isotactic polypropylene (iPP) was fabricated into oxidized polypropylene micro/nanoplastics (OPPs) via a thermal oxidation using hydrogen peroxide (H2O2) under various heating temperatures. The resulting OPPs were investigated in terms of the size distribution, surface chemistry, morphology, and thermal property as well as their concentration-dependent cytotoxicity to a human intestinal epithelial cell line (Caco-2), which could be a route to uptake NPs into the body through the food chain. The average diameters of the OPPs decrease with increasing reaction temperature. The OPPs obtained at 175 °C (OPP175) were spherical in shape and had a rough surface, with size distributions of approximately 0.14 ± 0.02 μm. A significant increase in the carbonyl content of the oxidized product was confirmed by Fourier transform infrared and X-ray photoelectron spectroscopy analyses. Caco-2 cells were exposed to OPP175 in a dose-dependent manner, and a significant loss of cell viability occurred at the concentration of 100 μg/mL. Thus, this study provides a fundamental approach for the fabrication of a model of NPs for the urgently demanded in vitro and in vivo studies to assess the potential impact of NPs on biological systems.