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High voltage power capacitors employ the oil-impregnated polypropylene film as the insulation. The swelling phenomenon might drive the antioxidants and small molecules within the film to migrate into the oil. It is necessary to comprehensively investigate the physical migration mechanism of antioxidants and their impact on the electrical performance of the oil-film combination insulation system and, consequently, formulate the proper selective prescription of antioxidants. Theoretical elucidation of the competitive interaction mechanism between the film and the oil in attracting antioxidant molecules was achieved through the calculation of inter-molecular binding energy, and the migration coefficient ηm was introduced to quantify the migration characteristics of antioxidants. Experimentally, the effects of antioxidants on the space charge distribution of the film, the dielectric properties of the oil, and the breakdown characteristics of both the film and oil were investigated. The experimental conclusions are consistent with theoretical analysis. The lamellar structure antioxidant molecules with ηm > 1 tend to migrate from the film to the oil, which results in increased dielectric loss and decreased breakdown strength of the insulating oil. In addition, the presence of phosphorus atoms in phosphite antioxidants contributes to a reduction in the breakdown strength of the film. For capacitor grade polypropylene film, in addition to the synergistic effect between different types of antioxidants on the thermo-oxidative stability, the structure of the antioxidant molecules and its influence on the electrical performance of the oil–film systems should also be taken into account. [ABSTRACT FROM AUTHOR]

Polypropylene (PP) has recently been actively investigated as a potential power cable insulation substitute for crosslinked polyethylene (XLPE). This is mainly due to PP's higher thermal withstand capability over XLPE. Notably, PP has much higher stiffness than XLPE and therefore needs to be modified with tougher materials to reduce its overall stiffness while maintaining its desirable dielectric properties. To date, many investigations have been conducted on the mechanical and dielectric effects of PP blended with various copolymers. Nevertheless, systematic investigations on the dielectric effects of PP blended with ethylene-based copolymers having different ethylene contents are less explored. The current work therefore reports on the impact of different ethylene contents of ethylene-based copolymers on the breakdown performances of PP. The findings reveal that PP blended with a copolymer having a low ethylene content (68.7 wt%) results in at least 11% higher breakdown performance than PP containing a copolymer having a high ethylene content (77.0 wt%). Specifically, PP containing 10 wt% of copolymers having 68.7 wt% of ethylene content results in comparable breakdown performance to XLPE (325 kV mm J). These results suggest that ethylenc-based copolymers with an appropriately low ethylene content can be blended with PP to achieve desirable breakdown properties. Highlights * PP is blended with copolymers of varying amounts and ethylene contents. * PP blended with low amounts of copolymers has good breakdown strength. * PP blended with low ethylene level copolymers has favorable breakdown strength. * PP blended with copolymers of low ethylene contents is desirable. * The breakdown mechanisms are related with the structure and permittivity. KEYWORDS breakdown, copolymer, dielectric, polymer blend, polypropylene, 1 | INTRODUCTION To date, crosslinked polyethylene (XLPE) is widely favored for insulating high voltage alternating current (HVAC) and high voltage direct current (HVDC) cables because of its outstanding dielectric [...]

This experiment was conducted to determine the growth performance, blood profile and carcass characteristics of broilers fed yellow maize stored in Polypropylene (PP) and ZeroFly[R] Hermetic (ZFH) storage bags for six months. Two hundred unsexed day-old Cobb-500 broiler chicks were randomly allocated to 2 treatments (2 storage bags) with 100 chicks per treatment in a Completely Randomized Design experiment. Each treatment had four replications with 25 birds per replicate. The experimental diets were formulated using the same quantities of maize stored in the PP and ZFH bags. The study was in three phases, that is, starter, grower and finisher phases and each had 22%, 20% and 18% crude protein (CP), respectively. The experiment lasted for six weeks. Feed and water were offered ad libitum. Statistical analyses were performed with SAS Version 9.4. Effects of storage bags were assessed using a one-way analysis of variance (ANOVA). Tukey's Honestly Significant Difference test was used as an option in the Mixed Procedure to determine differences between means (p < 0.05). Broilers on the ZFH bag dietary treatment recorded significantly (p = 0.035) higher weight gain in grams (2395.l1 [+ or -] 32.15), than their counterparts on the PP treatment (1980.30 [+ or -] 82.19). The feed conversion ratio, measured as feed: gain ratio, was better (p = 0.041) for the ZFH birds (1.74 [+ or -] 0.03) than the PP birds (2.24 [+ or -] 0.19). Birds fed the ZFH diet had higher (p < 0.05) dressing percentage (74.05 [+ or -] 0.24), percentage whole thigh (14.45 [+ or -] 0.10) and percentage drumstick (9.22 [+ or -] 0.16) than their PP counterparts. All the blood profile parameters measured were similar except total cholesterol and aspartate aminotransferase in which birds on the ZFH maize recorded higher values (p < 0.05). It was concluded that maize stored in ZeroFly[R] hermetic storage bags could be fed to broilers for better feed efficiency and carcass yield. Key words: Deltamethrin, grain storage technique, mycotoxin contamination, post-harvest loss, INTRODUCTION Undoubtedly, the two most indispensable nutrients in the diets of poultry are carbohydrates and proteins because they represent virtually 90% of the total cost of the ingredients in a [...]

Polypropylene (PP) is believed to be a rather promising cable insulating material for high‐capacity electric power system with low carbon emission due to its decent thermo‐resistance and recyclable nature. In this paper, a new dually chemical grafting modification strategy by methyl acrylate (MA) and acrylic acid (AA) is put forward to tailor the charge transportation behavior in PP, thus further enhancing the electrical properties. Experimental results indicate that the dually grafted PP with 2.3 weight percent (wt%) MA and 1.9 wt% AA shows enhanced volume resistivity and electrical breakdown strength than pure PP, and the space charge injection is significantly suppressed. This work further adopts thermally stimulated depolarization current (TSDC) test and computational analysis based on density functional theory (DFT) to reveal the mechanism of enhancement. The analysis shows that grafted chemical groups can introduce quantities of deep traps and electrostatic potential wells which are strongly correlated with the carbonyl group and would hinder the charge transportation thus improving the electrical insulating performances of PP. This work would provide a new route of PP‐based dually grafting modification for the development of high‐voltage cable insulation. [ABSTRACT FROM AUTHOR]

This study evaluated the influence of adding borosilicate residue (BS) as a flame retardant in polypropylene (PP) and natural fiber composites. The natural fibers used in this study come from the residue of the carpet industry, which is composed of PP and jute fibers (JT), while the PP used as the polymer matrix is postindustrial recycled material. The composites were produced by corotational twin‐screw extrusion and injection molding to obtain the test specimens. A coating process was carried out to add the water‐soluble fraction of BS to the surface of the compositions that did not receive it through incorporation during processing. To characterize the composites, flammability tests, thermogravimetric analysis (TGA), tensile strength test, and morphological analysis by scanning electron microscope (SEM) were performed. The addition of only 2 wt% BS content induces an increase in thermal stability of 32 and 109°C for composites with and without natural fibers, respectively. The addiction of 20 wt% BS elevates the elastic modulus up to 27% of the composites with and without natural fibers. The BS characterization indicates that it could be applied as a flame retardant when applied as coating methods using the water‐soluble fraction of BS, reducing the burning rate up to 92%. Flammability results are similar for formulations with and without natural fibers, indicating that the natural fibers did not influence the proposed flame retardant. The findings suggest that BS coating is a potential solution to improve the properties of natural fiber‐reinforced polymer composites while also promoting waste recycling. This approach produces composites with improved flammability, thermal stability, and mechanical properties, making them suitable for various end applications. [ABSTRACT FROM AUTHOR]

Highlights The performance of carbon fiber‐reinforced thermoplastic composites (CFRTP) has been restricted by the performance of the interface. In general, the interfacial properties of CFRTP are determined by both the surface properties of the carbon fiber (CF) reinforcement and the infiltration properties of the thermoplastic matrices, which possess high melt viscosity and seem difficult to sufficiently infiltrate the fiber reinforcement. As a result, the melt flow characteristics of different matrices significantly influence the interfacial melt penetration and mechanical properties of CFRTP. In this paper, in order to explore the influence of melt flow characteristics of various thermoplastic resins toward CFRTP interfacial behaviors, high‐polarity polyamide (PA) and low‐polarity polypropylene (PP) resins are selected as representative resin matrices among commonly used resin systems. Specifically, the polarity differences and interface‐forming mechanisms of CFRTP are first established. Following a systematical discourse on the latest research progress of interfacial modifications in PP/PA‐based CFRTP are described, centering on the effects of various modification methods on improving the interlaminar/interfacial strength, toughness, impact strength, and bending strength of the composites. In addition, this paper also classifies the interfacial mechanisms of CFRTP in terms of interface bonding, interface strengthening, and interface failure. Finally, the shortcomings and future research directions are pointed out to achieve effective interfacial construction and innovative modification of CFRTP. An introduction of resin polarity differences of CFRTP is established. An introduction of interface‐forming mechanisms of CFRTP is established. State‐of‐art characterization techniques of CFRPs interface are provided. Effect of melt flow property on the interfacial behavior of CFRTP was explored. The interfacial mechanisms are systematically analyzed. [ABSTRACT FROM AUTHOR]

Highlights Ground calcium carbonate (GCC) has the effect of reducing the incremental cost and improving the application performance as a plastic filler. In this study, waterborne polyurethane (WPU) was employed as a novel modifier for the wet modification of GCC. Polypropylene (PP)‐based composites incorporating GCC were then prepared for mechanical properties testing. The oil absorption value, wetting contact angle, and settling time in kerosene indicated that the modified GCC achieved an excellent modification effect with a WPU dosage of 2.0 wt%. The X‐ray Diffraction, Fourier Transform Infrared Spectroscopy, and X‐ray Photoelectron Spectroscopy results indicate that WPU was successfully coated on the surface of the GCC. SEM images revealed improved wettability and compatibility of GCC in the composites after modification. The mechanical tests showed that the GCC‐WPU/PP composites exhibited enhanced properties, including a flexural strength of 107 MPa, impact strength of 9.54 kJ/m2, tensile strength of 29.7 MPa, and an elongation at break of 30.9%. WPU was innovatively used as a modifier of GCC. An optimal modification effect was gained at the low dosage (2.0 wt%). GCC has excellent compatibility and wettability in PP composites. The obtained PP‐based composites have better mechanical properties. The study has the potential to apply GCC in plastics and other industries. [ABSTRACT FROM AUTHOR]

The main challenge of fused deposition modeling (FDM) is the limited variety of commercially available semicrystalline polymer materials. Isotactic polypropylene (iPP), with a fast crystallization rate and high crystallinity, tends to undergo extensive volumetric shrinkage during the FDM process, further inducing severe deformation and poor dimensional accuracy in 3D‐printed parts. This study aims to develop desirable iPP‐based materials for the FDM technique through physically blending iPP and thermoplastic polyester elastomer (TPEE). TPEE retards the nonisothermal crystallization ability of iPP, as indicated by the significant decrease in crystallinity (Xc) from 47.7% for neat iPP to 28.5% for the iPP blend at a weight ratio of 30/70. The suppressed crystallization behavior accounts for a drastic decrease in the warpage degree of the 3D‐printed parts. The greater the content of TPEE is, the lower warpage the 3D‐printed parts have. Additionally, the presence of TPEE slightly influences the shear viscosity of iPP. As a result, iPP blends exhibit excellent extrudability during a typical FDM process. TPEE also enhances the impact strength of 3D‐printed parts by 168% compared to that of injection‐molded iPP. Taken together, the iPP blends developed in this work are promising FDM feedstock materials with good dimensional accuracy and excellent impact strength. [ABSTRACT FROM AUTHOR]

The dimensional accuracy of injection molded parts plays an increasingly significant role in the plastics processing industry, as is the utilization of recycled raw materials. To obtain the desired dimensions and properties of injection moldings, various material modification methods are used simultaneously. The conducted research aimed to assess the impact of hybrid modification of non-nucleated heterogeneously isotactic polypropylene using recovered phosphogypsum and a chemical blowing agent on the shrinkage value and mechanical properties of injection molded parts. Additionally, changes in dimensions and properties of composites with solid and porous structures that occur within 1000 hours of their removal from the injection mold were determined. The research showed that the filler used acts as a nucleating agent causing an increase in the shrinkage of the parts, up to 10 wt%. Similar changes were observed in the case of tensile strength. The increase in the value of this parameter at the lowest phosphogypsum contents used was most likely the result of changes in the crystalline structure of polypropylene. Changes in the mechanical properties of the molded parts that occurred during conditioning are correlated with shrinkage changes that occur from the moment the molded parts are removed from the injection mold. Young's modulus and tensile strength increased linearly for both solid and porous moldings. However, the rate of stiffness increases as a function of shrinkage changes with the filler content. Nevertheless, the opposite tendency was observed in the case of changes in impact strength, the values of which decreased as a function of shrinkage to the greatest extent in the case of unfilled polypropylene. [ABSTRACT FROM AUTHOR]

In this study, the effects of reinforcement ratio, drill bit material, and drilling process parameters on the cutting forces generated during the drilling of glass sphere‐reinforced polypropylene composites were investigated experimentally. Test specimens were produced by conventional injection‐moulding of glass sphere reinforced polypropylene composite materials at 5 %, 10 % and 20 % wt. ratios. High speed steel, titanium‐coated high‐speed steel, and carbide drill bits with 4 mm diameter were preferred for drilling. In addition, the drilling process was carried out on a 3‐axis computer numeric control milling machine. Three different feed rates of 0.05 mm/rev, 0.10 mm/rev, and 0.15 mm/rev and cutting speeds of 12 m⋅min−1, 16 m⋅min−1, and 20 m⋅min−1 were determined for the drilling process. In addition, Taguchi experimental optimization method, analysis of variance and scanning electron microscopy were used to investigate the morphology of the drilled surface and the wear mechanisms occurring on the drill bit due to the drilling process. The test findings showed that the maximum torque value was 54.64 N⋅mm and the maximum thrust force was 100.43 N. The optimum test parameter for cutting forces was observed as C1D3FR1CS3. Drill parameter had an effect of 40.96 % on thrust force and 36.11 % on torque. [ABSTRACT FROM AUTHOR]

In this study, the effects of polypropylene (PP) composites produced by adding 10% old newspaper fibers (ONP), 5% microcrystalline cellulose (MCC), 3% polypropylene carbonate (PPC), and waste toner from 1% to 4% on the mechanical properties, physical properties, morphological, and thermal properties were investigated. According to the FTIR‐ATR and SEM‐EDS analysis results, it was determined that a significant part of the waste toner used in the study consisted of polystyrene co‐acrylate, and the remaining part consisted of carbon black and trace amounts of silicate. In the research, it was determined that the flexural and tensile strengths of MCC/ONP/PP composites containing 1% waste toner and 3% PPC increased by 13% and 46%, respectively, compared to the control sample. Additionally, the samples with the lowest water absorption values were measured in composites containing 1% waste toner and 3% PPC. The highest crystallinity value (50.75%) was obtained with the use of 1% waste toner and 3% PPC in MCC/ONP/PP composites. However, with waste toner usage above 1%, the mechanical, thermal properties, and water absorption rate have slightly decreased. As a result of the study, it was concluded that up to 1% waste toner with 3% PPC can be used successfully in MCC/ONP/PP composites. [ABSTRACT FROM AUTHOR]

Polypropylene double‐grafted maleic anhydride and bisphenol A epoxy resin (PP‐g‐M‐E) was successfully prepared by a single‐step method and characterized by Fourier‐transform infrared spectroscopy. Subsequently, it was employed as a compatibilizer to fabricate polypropylene (PP)/polyethylene terephthalate (PET) blends via melt extrusion. The content of the PET dispersed phase in the composite varied from 0 to 30 phr. The microstructure and morphology of the composites were characterized using scanning electron microscopy and Raman spectroscopy. The addition of PP‐g‐M‐E increased the interfacial interaction between the two phases and improved the compatibility and thermal stability of the system. In the presence of the compatibilizer, the crystallinity of the matrix phase (PP) increased, while that of the dispersed phase (PET) decreased owing to the heterogeneous nucleation effect of uniformly distributed PET. Double grafting of the PP‐g‐M‐E compatibilizer considerably enhanced the mechanical performance of the PP/PET blend system. The elongation at break of the modified sample exceeded that of the PP/PET blends by 117.55%, and the flexural and impact properties also showed considerable improvement. [ABSTRACT FROM AUTHOR]

In this work, poly(4‐methyl‐1‐pentene)/polypropylene/poly(4‐methyl‐1‐pentene) tri‐layer films were prepared. The microstructure of the film was adjusted by annealing in the temperature range of 150–237.5°C. Afterward, the influence of annealing and stretching temperature on the cavitation behavior of the film was investigated by small‐angle x‐ray scattering (SAXS). Results showed that for the "butterfly" scattering in the early stage, the radius of gyration (Rg) and maximum dimension (Dmax) of voids were ca. 75 and 200 nm, which were hardly influenced by annealing. Whereas, the volume fraction of voids was enlarged obviously, suggesting that more voids were formed; for the "streak" scattering in the late stage, the length of voids (Lv) grew gradually with stretching, and the ultimate value of Lv was 432.5 nm for un‐annealed film and 176 nm for film annealed at 230°C. Simultaneously, the misorientation of voids was reduced from 0.33 to 0.18. As the stretching temperature was elevated from 30 to 45 and 60°C, Rg and Dmax maintained at 75 and 200 nm, and Lv was enlarged to 434 and 432 nm. At the same time, the number of voids was reduced obviously. As the stretching temperature was 90°C, the voids were suppressed. [ABSTRACT FROM AUTHOR]

Polypropylene (PP) has been widely researched in power cable insulation due to its excellent resistance against high temperatures and high voltages. Since PP is too stiff for power cable extrusion, elastomers have been blended with PP to improve its stiffness. Although effects of elastomers on electro‐mechanical properties of PP have been widely studied, fundamental issues governing changes in dielectric properties of PP/elastomer blends have yet to be fully understood. This paper therefore reports on the properties of PP blended with ethylene‐based elastomer (EBE) and propylene‐based elastomer (PBE) by correlating their structural, mechanical, and dielectric investigations with respect to elastomer types and contents. The results show that blending increasing amounts of EBE and PBE improves mechanical flexibility of PP, with Young's modulus reduces by 53% at 40 wt% of elastomer content. Morphology‐wise, PBE demonstrates better compatibility with PP and less disrupted crystallinity compared to EBE. Furthermore, PP/PBE has better breakdown performance over PP/EBE, albeit that their breakdown strengths reduce with increasing elastomer contents. Specifically, direct current breakdown strength of PP/PBE reduces by only 21% at 40 wt% of PBE loading compared to 31% at equivalent EBE loading. Potential mechanisms governing breakdown changes are discussed with structural, mechanical, and dielectric interpretations. [ABSTRACT FROM AUTHOR]

The spherulitic morphology of isotactic polypropylene can be transformed into the oriented fibrillar morphology through hot stretching processes with varying temperature (Ts) or altering strain (εt). The effects of Ts and εt on the structural characteristics of fibrillar crystals are comprehensively investigated with respect to crystal orientation, long periodic spacing, lamellar thickness (Lc), crystallinity (Xc), melting point, and chain relaxation behavior. Small‐angle X‐ray scattering patterns illustrate that the fibrillar crystals consist of alternated stacks of crystalline lamellae and amorphous layers. High Ts leads to a low orientation degree of lamellae, whereas large εt facilitates a high orientation level. The Xc and mean Lc are improved continuously with the increasing of Ts or εt, indicating a stretching‐enhanced crystallization behavior driven by the two factors. The endothermic profiles reveal that new chain‐folded lamellae with relatively thinner thickness form during the hot stretching process. The formation of thinner lamellae is dominated by the melting–recrystallization mechanism. This work would provide guidance for optimizing process conditions to manipulate the microstructure of hot‐stretched semicrystalline polymers. [ABSTRACT FROM AUTHOR]

Context: This research assesses the influence of polypropylene (PP) fibers, both homopolymer and hydroxylated (PPOH), on the tensile properties of calcium silicate hydrate (C-S–H) composites through molecular dynamics (MD) simulations. Our models explore C-S–H matrices integrated with PP and PPOH fibers at varying polymerization degrees. The results demonstrate that both PP and PPOH fibers significantly influence the tensile strength and Young's modulus of the composites. Notably, PPOH fibers contribute to more substantial mechanical enhancements than PP, attributed to the increased polarity and enhanced intermolecular interactions from the hydroxyl groups. The study reveals a nonlinear relationship between polymer additive content and mechanical performance, with optimal properties at a polymerization degree of 20. Additionally, stress–strain analysis indicates that PPOH composites exhibit superior ductility and fracture energy, particularly at polymerization degrees of 20, showing enhanced ultimate strain and fracture energy by up to 9.6% and 13.9%, respectively, compared to PP counterparts. These results highlight the crucial role of tailored polymer additive composition and chemical modifications in maximizing the mechanical efficacy of C-S–H-based materials, enhancing their durability and structural performance. Methods: All MD simulations were conducted using LAMMPS. The models employed a combination of Clayff and Cvff force fields. During the entire tensile simulation, the system was configured under the NPT ensemble at 300 K. [ABSTRACT FROM AUTHOR]

This work aims to assess the possibility of using packaging industry waste to modify polypropylene products (PPs). The products were made in the form of extruded foil and injected samples. The products were produced using regranulate made of polypropylene cast foil. Maleic anhydride-modified polypropylene (MAPP) and polyolefin elastomer (POE) with a glycidyl ester functional group were used to modify the polypropylene. The samples were produced based on 50% foil waste reground and 50% pure PP. The rheological properties of the blends were assessed using the melt mass flow rate (MFR) technique; thermal properties using the differential scanning calorimetry method (DSC). The products manufactured using the injection molding method were subjected to an analysis of mechanical properties, such as tensile strength and impact strength. Also, in the case of film samples, tensile strength was assessed. Color-change assessments with CIE L*a*b* were carried out for all materials. Injection-molded products based on recycled metallized cast foil showed favorable mechanical properties such as tensile strength (1 MAPP = 26.7 MPa; 2 MAPP = 27.1 MPa), which was higher than the original material (cPP = 20.7 MPa). Also, for the films produced from regrind, the tensile strength was at a level similar (1 MAPP = 24.6 MPa; 2 MAPP/POE = 25.1 MPa) to the films extruded from virgin materials (cPP = 24.9 MPa). The introduction of a POE additive to the blends resulted in increased impact strength (1 MAPP/POE = 31 kJ/mol; 2MAPP/POE = 18 kJ/mol; 3 MAPP/POE = 11 kJ/mol) in relation to unmodified samples (cPP = 7 kJ/mol). The introduction of a POE additive to the tested mixtures improved the impact strength of the injected products by almost 4 times for sample 1 MAPP/POE and 2.5 times for sample 2 MAPP/POE in comparison to virgin cPP. These studies confirmed that foil waste can be successfully used to modify polypropylene products shaped both in the injection and extrusion processes. [ABSTRACT FROM AUTHOR]

In composite materials consisting of silver particles and a polypropylene matrix, the silver must migrate to the surface of the materials in order to exert on antibacterial effect. Substrates with various crystal structures may have different interactions with the silver particles, which can significantly impact the antibacterial performance. The research described in this paper investigates the influence of silver particles on the crystallization behavior of materials with varying crystallinity capabilities by selecting various polypropylene-based plastics and elastomers (Homopolymer polypropylene (PPH-T03), random poly(propylene/ethylene) copolymers (PPR-YPR503 and PPR-P340R), polyolefin elastomers (VERSIFY3000 (POE-1) and VERSIFY3401 (POE-2)), and ethylene propylene diene monomer for polymers (EPDM4725 and EPDM4770)). The research results indicated that the silver only entered the amorphous regions of the PP rather than entering the crystal regions, where they can more easily migrate to the material surface, resulting in a higher antibacterial effect. Therefore, the antibacterial degree of PP-Ag was as high as 99.9%. Silver can enter the micro-crystals of both the random copolymer polypropylene, (PPR-YPR503, PPR-1) and the random copolymer polypropylene, (PPR-P340R, PPR-2,) with a stronger effect on PPR-2. More silver entered the micro-crystals of PPR-2, and it was difficult for the silver ions to migrate out of the crystalline regions to exhibit antibacterial properties. The antibacterial degree of PPR-1-Ag was higher than that of PPR-2-Ag (77.8% vs. 66.7%). Similarly, silver had a greater impact on the lamellar structure of the polyolefin elastomer (VERSIFY3401, POE-2) compared to the polyolefin elastomer (VERSIFY3000, POE-1). In comparison with POE-2-Ag, POE-1-Ag exhibited a higher antibacterial degree (79.6% vs. 57.4%). Research on the two types of ethylene propylene diene monomer (EPDM) composite materials indicated that EPDM-1 exhibited a lower Mooney viscosity and poorer flowability. The EPDM-1 tended to encapsulate the silver within its molecular chains, thereby impeding the migration of silver to the surface. The optical performance analysis indicated that silver antibacterial agents had little impact on the optical properties of PP-Ag, PPR-1, PPR-2, POE-1, POE-2 and the EPDMs. We suggest that this research provides theoretical guidance for selecting highly antibacterial polypropylene materials. [ABSTRACT FROM AUTHOR]

In this study, lanthanum oxide (La2O3) nanoparticles or lanthana were synthesized by the planetary ball milling method and then used as a filler for the preparation of the polypropylene (PP) based nanocomposites by solution mixing method. The PP used in the study was derived from the discarded saline bottles. The structural and the surface morphology of the synthesized lanthanum oxide nanoparticles were characterized by XRD, SEM and FTIR. The thermogravimetric analysis (TGA) study revealed that the thermal stability of the nano lanthana composites increased with the addition of the lanthanum oxide nanoparticles. The mechanical properties, such as Young's modulus and tensile strength, were also improved by the addition of the lanthanum oxide nanoparticles to the PP matrix. The composites also showed antibacterial activity against Escherichia coli bacteria. This approach not only mitigates medical plastic waste and environmental impact but also paves the way for versatile polymer nanocomposites with extensive industrial applications, especially in biomedical packaging. [ABSTRACT FROM AUTHOR]

Hybrid interaction/co‐working mechanisms of waste cellulose (WC) fibers and expanded vermiculite (V) in polypropylene (PP) resulted in stronger, stiffer, and thermally durable composites are presented. Fibrous WC and particulate V inclusions were mixed with the PP matrix via high shear thermokinetic mixer under 4000 rpm. Thermal and mechanical characterization efforts assisted with fractographic investigations are performed on five sample sets such as (i) two‐phase WC fibrous PP composites and (ii) three‐phase WC–V hybrid composites. Results suggested that as the main reinforcement agent WC is able to increase the axial stiffness of PP (1.7 GPa) up to 4 GPa (30WC) as the weight fraction increases with a reduction in ductility. However, a strength threshold due to WC cluster entanglement, which leaves partially non‐wet clusters of WC and limited crystallization volume for PP at high WC weight fractions, is noted. In situ formed V platelets placed between WC fibers are proven to provide PP crystallization loci to further increase the axial stiffness (4.1 GPa) and matrix brittleness. When used with 10WC, they significantly increased the ability of PP matrix r to resist the failure events associated with the presence of randomly aligned WC fibers. Such ability is further highlighted in the 20WC10V case where the inherent problem of WC entanglement increased the contribution of polymer shear failure to the overall tensile response of manufactured composites. A significant increase in tensile strength (55%) for this case was recorded which makes the proposed hybridization effort more advantageous to conventional short fiber reinforcing strategies. Highlights: Stiffer and stronger PP‐based hybrid composites with waste cellulose and vermiculite.Tensile failure/toughening mechanisms in hybrid PP compositesSustainable approach for reinforcement selection. [ABSTRACT FROM AUTHOR]

Polypropylene (PP) was a very practical and important thermoplastic, which was widely used in various fields due to its low cost, universal, and corrosion resistance. However, the moderate mechanical and heat resistance properties of PP limited its application in some special fields. In this paper, nucleating agents NP‐657 were added to further improve its mechanical and heat resistance performances of PP (300H). Furthermore, the heterogeneous nucleation of NP‐657 reduced the crystal size and increased the crystal density of 300H. With the rise of NP‐657 content, the crystallization rate of different PP systems increased significantly, such as the t1/2 of 300H‐0.2 reduced by 31.9 min in comparison with that of 300H at 140°C. At the same time, the crystallinity of 300H‐0.05 with 0.05 wt.% NP‐657 increased by about 5.96% compared with 300H. In addition, 300H‐0.05 has the highest tensile strength (23.9 ± 0.6 MPa), flexural modulus (1273.3 ± 67.3 MPa), and the highest thermal deformation temperature (88.5 ± 7.7°C) in different PP systems. In general, this paper provided a reference for the fabrication of PP with satisfactory mechanical and heat resistance performances. Highlights: 300H‐0.05 had a maximum crystallinity of 40.8 ± 0.2% in different PP systems.The flexural modulus of 300H‐0.05 was 434 MPa higher than that of 300H.The tensile strength of 300H‐0.05 increased to 23.9 ± 0.6 MPa.300H had the highest thermal deformation temperature of 88.5 ± 7.7°C. [ABSTRACT FROM AUTHOR]

The European Union (EU) regulations mandate 10% of all food packaging to be reusable by 2030. United States (U.S.) exporters of specialty crops face new challenges in ensuring microbiological food safety using reusable packaging. A novel antimicrobial formulation consisting of ammonium carboxylate salt of capric acid and L-arginine (GS-2) was recently developed as a spray coating chemical for food packaging materials. In this study, we evaluated the antimicrobial efficacy of GS-2 against microbial strains representing three foodborne bacterial pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella enterica), one fungal spoilage organism (Aspergillus niger), and one surrogate viral pathogen (murine norovirus) on three reusable plastic materials (acrylonitrile butadiene styrene, high-density polyethylene, and polypropylene) and one cardboard packaging material, respectively. Different chemical concentrations, exposure times, and storage conditions were individually evaluated for the relative antimicrobial efficacies of GS-2 against these microorganisms. Our results showed that GS-2 was highly effective for inactivating bacterial pathogens on both plastic and cardboard surfaces. For instance, 3% GS-2 achieved a >5 log CFU/in2 reduction in E. coli O157:H7, L. monocytogenes, and S. enterica on tested plastic surfaces at an exposure time of 60 min. However, its efficacy against A. niger and murine norovirus was less optimal, resulting in a ≤1 log CFU/in2 reduction on all tested surfaces. Based on our study, GS-2 demonstrated a strong potential as an antibacterial coating reagent for reusable food packaging materials to minimize pathogen contamination and ensure the safety of the specialty crops. [ABSTRACT FROM AUTHOR]

Thermal resistance of cold-weather clothing is achieved by layering and filling. In this study, kapok/polypropylene blended (70/30, 60/40, and 50/50) needle-punched nonwovens were manufactured with 100 and 200 g/m2 areal density. Chicken feather fibers were used as fillers for developing quilted composite structures (QCS). To produce a QCS, 100 and 200 g/m2 nonwovens were individually used as the top and bottom layers, and the middle layer was filled with chicken feather fibers in 100, 200, 350, 550, 600, and 850 g by weights. The structures were characterized for thermal properties, and it was noted that 70/30 kapok/polypropylene nonwovens in 100 g/m2 set had the highest thermal resistance between 0.5901–0.6461 °C m2/W. Thermal resistance is greatly influenced by kapok, chicken feather fiber quantity in the assembly along with the areal density (1000 g/m2) of the QCS. Results show that the developed QCS has higher thermal insulation and can be used for cold-weather apparel and sleeping bag. [ABSTRACT FROM AUTHOR]

Emerging legal requirements will likely considerably heighten demand for high-quality recycled raw materials for e.g., packaging and automotive applications; key EU legislation mandates recycling as the future end-of-life option for municipal solid plastic waste. Yet recycled plastic use remains low due to safety concerns, undesirable aesthetic, olfactory, and mechanical properties, mainly attributable to contaminants present in recyclates. Advanced treatment options for recovered polypropylene (PP) packaging and the impact of such treatments on the polymer are currently poorly documented. We investigated the effectiveness of hot/cold washing and hot air devolatilization treatments in removing volatile substances from residential post-consumer PP plastic waste to improve its scope of application and value and to assess possible side effects on mechanical and processing parameters. Cold- and hot-washed recyclates exhibited similar contaminant levels and most substances were removed within 7 h. The recycling procedure had no adverse effects on mechanical or processing parameters although reprocessing caused polymer degradation, indicated by decreasing viscosity, elongation at break, and tensile strength. Washing and hot air devolatilization treatment of plastic wastes improve their scope of application and value by enhancing mechanical properties and considerably reducing the amounts of odorous substances, but is often not suited to high-quality applications, such as packaging. The dominance of packaging waste and strict legislation on food-grade recyclate applications will make widespread recyclate use challenging since it represents the primary use of plastic. Recyclate must consequently be extensively utilized in non-food contact applications until advances in waste sorting, washing, and devolatilization yield less contaminated recyclates with improved properties. [ABSTRACT FROM AUTHOR]

The current study aims to model and optimize the catalytic pyrolysis of plastics, incorporating an agricultural biomass waste-derived catalyst. Polystyrene (PSW) and polypropylene (PPW) are experimented with thermal and catalytic pyrolysis. Agricultural biomass waste (wheat husk) was selected and acid treated with sulfuric acid (HZSM-5SA) and hydrochloric acid (HZSM-5CA), and then used as catalyst. Thermal and catalytic pyrolysis were conducted in a semi batch reactor, with reaction temperature (500 ℃) and different ratios (10:1, 10:2 & 10:3). At a ratio 10:2, PSW with HZSM-5SA produced 91.19 wt.% of oil yield and PPW with HZSM-5SA produced 85.73 wt.% of oil yield. The catalyst HZSM-5SA was effective in the reduction of reaction temperature and time, it decreased from 450 ℃ to 437 ℃ and 22 min to 14 min for PSW. Catalyst activity was also observed for PPW, the reaction temperature decreased from 471 ℃ to 456 ℃ and 34 min to 19 min. Oil properties were determined and it was found that the kinematic viscosity of oil obtained from PSW with HZSM-5SA was 2.53 cSt, which coincide with the diesel Bharat Stage (BS VI 2020). Total conversion of pyrolysis products was predicted using six Machine Learning (ML) models such as Random Forest, Support Vector, K-Nearest Neighbor, Decision Tree, AdaBoost, and Gradient Boost. Among all the models, the Gradient Boost regressor model had a good evaluation metrics of R2 value of 0.984 and RMSE of 0.019, respectively. This study illustrates the use of ML models to predict the total conversion and their correlation matrix with target and feature variables. This study also highlights that cost-effective catalyst can be prepared from biomass (wheat husk) and the use of ML models to train the datasets and evaluate the actual and predicted values. Highlights: In situ catalytic pyrolysis of PSW and PPW was experimented. HZSM-5 prepared from agricultural biomass waste (wheat husk). Enhanced liquid yield of 91.19 wt.% obtained for PSW + HZSM-5SA. 70.19 wt.% of diesel-like fractions obtained in oil yield. Machine Learning model—Gradient Boost algorithm predicted the total conversion of products with R2 0.984. [ABSTRACT FROM AUTHOR]

The automotive industry is under significant pressure to curb greenhouse gas emissions from their products as the negative impacts on the environment are increasingly apparent. As such, there is significant interest within the industry to develop low-carbon footprint materials. Natural fiber composites are therefore appealing due to both their decreased carbon footprint, as well as their relatively low cost, low density, and beneficial acoustic properties. This research specifically focuses on the use of paper fibers as composite reinforcements. Paper offers additional benefits over other natural fiber types in that it is globally available, does not compete with food resources, and has well-established quality control techniques. The goal of this work was to study the manufacturing of polypropylene (PP)-paper fiber composites using a hybrid wet-lay/compression molding processing. The processing parameters studied included molding temperature, molding duration, and molding pressure. Paper composites were characterized for properties including flexural strength, impact strength, and water uptake rate. An optimal set of processing parameters was identified in which cycle time and energy inputs (e.g. temperature and pressure) were minimized while retaining desired material properties. [ABSTRACT FROM AUTHOR]

In this work, a new compatibilizer, ternary monomer grafted polypropylene (hereafter shorted as: G‐PP), was successfully synthesized by solid phase grafting of maleic anhydride, methyl methacrylate, and butyl‐acrylate onto polypropylene. For all developed polypropylene matrix composites, the prepared G‐PP evidently showed enhancing mechanical properties on PP/wood flour (WF) composites, which is obviously superior to those from maleic anhydride grafted polypropylene (W‐PP) and virgin polypropylene (C‐PP). In particular, the wettability of G‐PP was greatly improved, while the melting temperature and β crystal phase amounts of the WF composites with G‐PP are much higher when compared to that of W‐PP and C‐PP. This can be reasonably explained by the formation of continuous micropores and filaments in WF composites containing G‐PP, as verified by hot stage polarizing optical microscope (POM). Meanwhile, the G‐PP effectively reduced movement of molecular chains of WPC and formed a better interface layer with WF, which contributed to penetrate more deeply and form micro‐crosslinking in the WF layer. We believe that the results reported in this work will increase the added value of polypropylene based wood plastics composites (WPC) and allow WPC to participate in lightweight and environmentally friendly products. [ABSTRACT FROM AUTHOR]

The present work provides a unique insight to reveal the long chain branching (LCB) influence to the nano‐fillers, that is via analyzing the conductivity evolution during the thermal annealing, fast shear flow and melt to solid cooling process. Meanwhile the crystallization behavior is also discussed. A linear polypropylene (PPC) and a long chain branched polypropylene (PPH) are chosen as the two polymer matrices with carbon nanotubes (CNTs) as the nanofillers. During the thermal annealing process, a more obvious growth of electrical conductivity of linear PPC nanocomposites are observed compared with LCB PPH nanocomposites. The harder movement of CNTs inside LCB PPH matrix may be the main reason. This also can be reflected by the conductivity evolution during slow cooling process where a decrease‐then‐increase (DTI) phenomenon is found for PPC/CNTs systems due to the rebuilding of CNTs conductivity network after crystallization. By contrast, this does not happen for PPH/CNTs systems. [ABSTRACT FROM AUTHOR]

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Polyolefins such as polyethylenes and polypropylenes are the most‐produced plastic waste globally, yet are difficult to convert into useful products due to their unreactivity. Pyrolysis is a practical method for large‐scale treatment of mixed, contaminated plastic, allowing for their conversion into industrially‐relevant petrochemicals. Metal–organic frameworks (MOFs), despite their tremendous utility in heterogeneous catalysis, have been overlooked for polyolefin depolymerization due to their perceived thermal instabilities and inability of polyethylenes and polypropylenes to penetrate their pores. Herein, we demonstrate the viability of UiO‐66 MOFs containing coordinatively‐unsaturated zirconium nodes, as effective catalysts for pyrolysis that significantly enhances the yields of valuable liquid and gas hydrocarbons, whilst halving the amounts of residual solids produced. Reactions occur on the Lewis‐acidic UiO‐66 nodes, without the need for noble metals, and yield aliphatic product distributions distinctly different from the aromatic‐rich hydrocarbons that can be obtained from zeolite catalysis. We also demonstrate the first unambiguous characterization of polyolefin penetration into UiO‐66 pores at pyrolytic temperatures, allowing access to the abundant Zr‐oxo nodes within the MOF interior for efficient C−C cleavage. Our work highlights the potential of MOFs as highly‐designable heterogeneous catalysts for depolymerisation of plastics, which can complement conventional catalysts in reactivity. [ABSTRACT FROM AUTHOR]

It is known that X‐ray CT of organic polymer materials usually provides low‐contrast images because of the low X‐ray absorption of these materials. In this paper, we describe a new method to enhance the contrast of X‐ray CT images of organic polymer materials. We demonstrate that gamma‐ray irradiation of poly (ethylene terephthalate) (PET) fibers in dichloromethane containing 2‐bromoethyl methacrylate, 2‐chloroethyl methacrylate, or 4‐bromostyrene results in the grafting of halogen‐containing oligomeric chains onto the PET fibers. Focused ion beam scanning electron microscopy (FIB‐SEM) and time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) analyses revealed a homogeneous distribution of bromine atoms within the 2‐bromoethyl methacrylate‐modified PET fibers, not only on the surface. This uniform incorporation translated to a significant improvement in X‐ray CT image contrast compared with pristine fibers. Similar treatment of polypropylene pellets also enhanced the contrast of their X‐ray CT images. This is a new simple and effective method to enhance the X‐ray CT image contrast and potentially applicable to various polymer materials including polymer composites and porous polymer materials, readily allowing the observation of their 3D microstructures finely. [ABSTRACT FROM AUTHOR]

Seasonal variation in microplastics abundance, occurrence, and distribution in pelagic and demersal fishes was observed in this study during December 2021 to November 2022. One hundred percent presence of microplastic in inedible (gut and gills) tissue, while 82% and 54% in edible tissue (muscle) of pelagic and demersal fishes respectively were seen. Post-monsoon period showed high prevalence of microplastics followed by monsoon and the least during pre-monsoon in both pelagic and demersal fishes. In pelagic fishes, the edible tissue had microplastics abundance of 1.56 to 13.34 numbers per 10 g of tissue whereas inedible tissue had 3.36 to 16.67 numbers per 10 g of tissue. In demersal fishes, the edible tissue had microplastics abundance of 1.04 to 5.26 numbers per 10 g of tissue while it was 2.67 to 8.34 numbers per 10 g of inedible tissue. There was significant variation in abundance of microplastic in edible and inedible tissue of all the fishes (Mann–Whitney test, p < 0.05). The most dominant microplastics size was 0.005–0.05 mm followed by 0.05–0.5 mm and the least of greater than 0.5 mm in pelagic and demersal fishes respectively. Taking microplastic shape into consideration, the most dominant was fiber followed by fragment and the film in inedible tissue of all the fishes. The edible tissue of all the fishes had only fiber in them (100% occurrence). The dominance of blue color microplastics was observed followed by red, green, yellow, and orange at least in edible as well as inedible tissues of the fishes. More than 99% microplastics polymer observed in this study include polyethylene (PE), polypropylene (PP), and polystyrene (PS); only less than 1% was unidentified. This is the first study done on seasonal variation of microplastic in the marine fish population of Gujarat waters, Northeast Arabian Sea. The study highlights the nature of micro-pollutant in marine environments, emphasizing the need for comprehensive monitoring and management strategies. [ABSTRACT FROM AUTHOR]

AbstractOur research described in this paper investigated the environmental degradation of polypropylene (PP) films incorporating pro-oxidants and assessed their impact on the ecosystem. Weathering aging effects were monitored through Fourier-Transform Infrared (FTIR) analysis, revealing significant changes in carbonyl, hydroxyl and amorphous regions post-aging. The presence of pro-oxidants intensified these changes, indicating higher oxidation levels. Contact angle measurements demonstrated decreased hydrophobicity upon aging, particularly pronounced in pro-oxidant-containing films (initial contact angle: 87.79° for PP/1% Co/1% Fe, sample (F6) decreased to 79.24° after aging). Differential Scanning Calorimetric (DSC) analysis revealed decreased melting temperatures (initial Tm: 159.5 °C for F6 decreased to 148 °C after aging) and the crystallinity post-aging (initial χ: 73.25% for F6 decreased to 60.17% after aging), suggesting increased susceptibility to degradation. Thermogravimetric Analysis (TGA) showed decreased thermal stability after aging, especially in PP/pro-oxidant films; the Tonset (T5); 432.00 °C for F6, decreased to 268.00 °C after aging; where Tonset is the temperature corresponding to 5% weight loss. Biodegradation tests indicated enhanced biodegradability in the pro-oxidant-containing films, with cobalt and ferrous stearate mixtures showing the highest degradation degrees (e.g., PP/1% Co/1% Fe: ≈ 77% biodegradation after 140 days). Ecotoxicological evaluations, including microbial toxicity and plant germination and growth tests, revealed no inhibitory effects of the degradation products on soil flora or plant growth, confirming their nontoxic nature. Overall, we believe this comprehensive study provides insights into the environmental fate of PP films with pro-oxidants, highlighting their potential for accelerated degradation without adverse ecological impacts. [ABSTRACT FROM AUTHOR]

Background: To introduce a new flange technique (called the Z.S. fixation technique) for 8 − 0 polypropylene suture in scleral fixation of a one-piece intraocular lens (IOL) and evaluate its effectiveness and safety. Methods: All surgeries were performed using two strategies. First, the Z.S. fixation technique was used to fix 8 − 0 polypropylene sutures to the sclera and the two haptics of a one-piece IOL, respectively. The one-piece IOL previously implanted in the anterior chamber was then relocated to the posterior chamber. Finally, the suture ends outside the sclera were cauterized into flanges and buried in the sclera. All effectiveness and safety data related to the Z.S. technique were recorded and compared. Results: The Z.S. fixation technique was employed in 16 eyes of 13 patients, with a follow-up duration of at least 6 months. Postoperative uncorrected distance visual acuity (UDVA) was greatly improved in most of the operated eyes (11/16). The mean log MAR UDVA after surgery was significantly improved compared with that before surgery (0.93 ± 0.72 vs. 1.53 ± 0.73, P = 0.002). IOLs in the vast majority of operated eyes (15/16) remained stable during half-year follow-up. No severe intra-/post-operative complications were observed in any of the operated eyes. Conclusion: The Z.S. fixation technique for 8 − 0 polypropylene suture in scleral fixation of one-piece IOL reduced surgical injuries and had ideal surgical effectiveness and safety. Significance: What was known: To date, most 10 − 0 polypropylene suture scleral fixation techniques required knot fixation outside the sclera, which inevitably leads to long-term complications related to 10 − 0 sutures, such as suture erosion, knot exposure, and late suture breakage. Therefore, some scholars began to use 8 − 0 polypropylene suture to perform scleral fixation for one-piece intraocular lens with specific structures, but the scope of application was very narrow. What this paper adds: We introduced a compound technique of electrocoagulation fixation and scleral flapless knotless interlaminar anchoring for 8 − 0 polypropylene suture, which can be applied to most one-piece intraocular lenses. [ABSTRACT FROM AUTHOR]

In this study, the thermoforming formability of continuous glass fiber-reinforced polypropylene (CGFRPP) laminates below the melting temperature were investigated. The forming limits of CGFRPP laminates were explored using flexural tests, Erichsen tests and deep drawing tests. The failure mechanism of CGFRPP in thermoforming was investigated by observing typical failure specimens using a microscope. The results show that the flexural performance and Erichsen performance are optimal at 130 °C and 2 mm/min. At 160 °C and 100 mm/min, the deep drawing performance is optimal. The restriction of fibers by the matrix is affected by the deformation temperature, and the creation of defects is affected by the deformation rate. During forming, the CGFRPP laminates undergo shear and extrusion deformations, resulting in wrinkles, delamination, and fiber aggregation. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The polypropylene (PP) synthesis process is crucial in the plastics industry, requiring precise control as it directly impacts the catalytic activity and the final product's performance. This study investigates the effects of trace amounts of four different mercaptans on the polymerization of propylene using a fourth-generation Ziegler–Natta (ZN) catalyst. Various concentrations of these mercaptans were tested, and results showed that their presence significantly reduced the melt flow index (MFI) of the final PP. The most notable MFI decrease occurred at 37.17 ppm of propyl mercaptan and 52.60 ppm of butyl mercaptan. Methyl and ethyl mercaptan also reduced the MFI at lower concentrations, indicating that mercaptans act as inhibitors by slowing down the polymerization process and reducing the fluidity of molten PP. The highest MFI increase was observed at lower concentrations of each mercaptan, suggesting that smaller molecular inhibitors require less concentration. This trend was also seen in the catalyst's productivity, where lower concentrations of methyl mercaptan reduced PP production more effectively than higher concentrations of butyl mercaptan. Fourier transform infrared spectroscopy (FTIR) identified interactions between the mercaptans and the ZN catalyst. Computational analysis further supported these findings, providing insights into the molecular interactions and suggesting possible inhibition mechanisms that could impact the final properties of polypropylene. [ABSTRACT FROM AUTHOR]

Smart materials react to external triggers by changing size, color, mechanical properties, or permeability. The next generation of smart materials will be able to not only recognize and react to external triggers but also to their dynamics. The only existing example of such a material is heating rate‐sensitive polymorphous cross‐linked syndiotactic polypropylene. This study presents a new principle of a heating rate‐sensitive material on the example of cross‐linked and fully amorphous quenchable semi‐crystalline polyethylene terephthalate (x‐PET). The x‐PET is stretched to high elongation above its melting temperature and constrained quenched to a fully amorphous state. Then the polymer is heated to 120–170 °C with different heating rates. Due to its heating‐rate sensitivity, x‐PET shrinks to different stabilized lengths dependent on the heating rate. The new length can be used to read out the heating rate and to specifically answer to this by mechanically switching a process. Detailed analytics of this process reveal that amorphous stretched x‐PET is starting the retraction above Tg and simultaneously stopping it by crystallization. The different rates of these processes result in the heating rate sensitivity of x‐PET. [ABSTRACT FROM AUTHOR]

Highlights The demand for polymers with antibacterial properties is increasing in food packaging industry and medical supplies. Antibacterial additives without toxic metal ion release are crucial for health and safety but still have challenges. Herein, polypropylene (PP) nanocomposite was prepared with polyaniline/graphene nanocomposite (PANI/GNP) as a green antibacterial additive due to its electrostatic, free radical, and nanoknife effect synergistic antibacterial mechanisms. To improve the dispersibility of PANI/GNP, nanosilica coating on PANI/GNP was constructed successfully with in situ condensation polymerization of epoxy functionalized ethyl orthosilicate to obtain EP‐nSiO2‐PANI/GNP. EP‐nSiO2‐PANI/GNP with a thin nanosilica coating has a significantly improved thermal stability as compared with that of PANI/GNP characterized by TGA. The EP‐nSiO2‐PANI/GNP presents a nanoscale disperse state in PP nanocomposite and thus enhances the melt viscosity and storage modulus accordingly characterized by TEM and Rheology. The EP‐nSiO2‐PANI/GNP/PP filled with 0.5 wt% of EP‐nSiO2‐PANI/GNP demonstrates antibacterial activity of 100% against both Escherichia coli and Staphylococcus aureus. In situ condensation polymerization to prepare EP‐nSiO2‐PANI/GNP. EP‐nSiO2‐PANI/GNP has enhanced dispersion stability. EP‐nSiO2‐PANI/GNP with a thin nanosilica coating has a good thermal stability. PP nanocomposite with 0.5 wt% filler has excellent antibacterial activity. The electrostatic, free radical, and nanoknife effect antibacterial mechanism. [ABSTRACT FROM AUTHOR]

This paper aims to predict the damage and fracture behavior of thermoplastic fiber-reinforced metal laminates (TFMLs) under ballistic impact loadings. A dynamic metal constitutive model has been employed and implemented in Abaqus/Explicit through a vectorized user material subroutine (VUMAT). The effects of the Lode angle, temperature, and strain rate are considered in the strength model, while the effects of stress triaxiality, Lode angle, temperature, and strain rate are taken into account in the failure criteria. To assess the validity and superiority of the proposed model, the numerically predicted responses of polypropylene fiber-reinforced metal laminates subjected to varying impact energies were systematically compared with corresponding experimental results. Additionally, a comparative analysis was performed between the numerical simulation results predicted by the present model and those obtained using other constitutive models, such as the Johnson–Cook (JC) constitutive model and the elastoplastic constitutive model. Furthermore, the effect of projectile types on the ballistic performance of TFMLs have been systematically investigated. The findings demonstrate that the failure pattern predicted by the current model closely aligns with the experimental observations, while both the Johnson–Cook (JC) constitutive model and the elastoplastic constitutive model were unable to accurately replicate the experimentally observed failure behavior. This study also reveals that the projectile's nose shape plays a significant role in influencing the perforation behavior of TFMLs, affecting both the residual velocity and damage. [ABSTRACT FROM AUTHOR]

In specific applications like ice-repellent coatings or membrane separation technology, wettability is a key parameter affecting the applicability of commodity polymers. This study presents a technique to fine-control the wetting properties of a hierarchically structured polypropylene surface, enabling the transition between superhydrophobic and superhydrophilic states. To demonstrate the tunability of the wetting properties of polypropylene (PP) substrate, we prepared in a consecutive way superhydrophobic (advancing contact angle (CAadv) of 152°) and superhydrophilic (CAadv of 0°) material by solvent-treatment and mild air plasma treatment. The optimal plasma treatment parameters to achieve superhydrophilic wetting behaviour, which is stable for at least one week of storage in air was also explored. Water contact angle measurement and X-ray photoelectron spectroscopy were used to monitor the time dependency of hydrophobic recovery on a hierarchically structured PP surface. With a simple model considering structural and wetting parameters, we characterized the droplet spreading behaviour of plasma-treated roughened surfaces, which exhibited superhydrophilic wetting behaviour with equilibrium CAadv of nearly 0°. The proposed model, which aligns well with experimental data, can be used to compare the droplet spreading behaviour of plasma-treated roughened surfaces. [ABSTRACT FROM AUTHOR]

Material extrusion and injection molding are prevalent in polymer processing, but wood fiber‐reinforced polymer composites offer eco‐friendly alternatives for industries like automotive, and aviation. Our study explores biocomposites using bleached chemi‐thermomechanical pulp (BCTMP) and polypropylene (PP). BCTMP is rich in cellulose and hemicellulose and quite hydrophilic, while PP's hydrophobic structure creates a disconnect to creating a composite of the two. Traditional methods add costly coupling agents like maleic anhydride polypropylene (MAPP) in an attempt to enhance the adhesion properties of wood‐plastic composites. However, it is worth noting that even in the presence of MAPP, PP maintains its high hydrophobicity and low surface energy, despite exhibiting considerable heterogeneity. Further complexity arises from the thermal degradation characteristics of BCTMP during the melting processing of PP. Our proposed method involves premixing via cryo and planetary ball milling. This boosts PP and BCTMP adhesion, enhancing dispersion quality and mechanical properties without needing coupling agents. Moreover, the premixing of BCTMP and PP forms a thermal buffer layer around BCTMP, minimizing its thermal degradation during processing. This process also ensures even distribution of BCTMP into PP, resulting in a 200% rise in Young's modulus with 30 wt% BCTMP without compromising ultimate tensile strength. Highlights: Exploration of biocomposites using bleached chemi‐thermomechanical pulp (BCTMP) and polypropylene (PP) thorough injection moldingImplementation of premixing to enhance PP/BCTMP adhesion without coupling agentsPremixing reduces thermal degradation of BCTMP, enhances dispersion, and improves mechanical propertiesAchieving a 200% increase in Young's modulus with 30% BCTMP incorporation, while maintaining ultimate tensile strength [ABSTRACT FROM AUTHOR]

Despite extensive research, the stabilization mechanism of mesomorphic isotactic polypropylene (iPP) at room temperature has not been elucidated completely. To address this issue, nanoscale structural information is indispensable. In this study, mesomorphic‐α phase transition is studied with synchrotron wide‐angle diffraction and small‐angle X‐ray scattering. It is found that during phase transition, the mobile amorphous content remained unchanged, while rigid amorphous fraction (RAF) decreased constantly, accompanied by an increase in long period. Assuming that the increase in long period is induced by the extension of the rigid amorphous coil (RAC), the thickness of RAF (RRAF) is estimated, which is found to be 2.2 nm. This value is greater than the length of b axis in α crystal cell, which can be the reason that folded‐chain iPP clusters in mesomorphic iPP cannot approach closer to form α crystal at room temperature. Besides, with RRAF, the thickness of smectic layer is estimated, which is found to be 0.9 nm. At this thickness, bulk‐free energy cannot compensate for the folded‐surface free energy, which can be the other reason that mesomorphic iPP chains cannot transit into α crystal at room temperature. The information obtained in this study is favorable for understanding the stabilization mechanism of mesomorphic iPP. [ABSTRACT FROM AUTHOR]

Our work consisted of producing an indirect solar cooker, equipped with a thermal energy storage system for cooking food under shelters. To achieve this objective, we proceeded to the dimensioning of the system by defining the components necessary for its realization. For this purpose, various processes for the development of parts, such as foundry and welding were used. Thus, an indirect solar cooker was designed, integrating a cylindrical-parabolic concentrator focusing the heat which is conveyed to a cooking tank filled with commercial polypropylene, serving as a phase change material (PCM). The system was subsequently tested under different weather conditions in order to evaluate and validate its performance. It emerges from this work that the integration of a PCM in an indirect solar cooker ensures its energy autonomy, that is to say its use in times of no sunshine, considerably improves its efficiency and offers a viable solution for cooking in rural areas without access to electricity. This device helps reduce dependence on fossil fuels and improve food security in sunny regions. [ABSTRACT FROM AUTHOR]

Paving blocks are a composition of building materials made from a mixture of cement, water, and aggregates in a certain ratio. This study uses PP plastic as a substitute for cement in Paving blocks. The purpose of this study is to determine the compressive strength characteristics of various Paving block shapes by utilizing 50% Polypropylene (PP) plastic as a substitute for cement, and to identify obstacles in making Paving blocks. Paving blocks are produced at the Civil Engineering Laboratory of Balikpapan University, South Balikpapan District, Balikpapan City, East Kalimantan. This study involved variations in a mixture of PP plastic and sand with the following ratio: 50% PP plastic: 50% sand. This test was also conducted at the Civil Engineering Laboratory of Balikpapan University. The results of this study indicate that the highest compressive strength occurs in the hexagon shape of a mixture of 50% PP plastic: 50% sand, reaching 16 MPa. From all tests for block, diamond, and hexagon shapes, it can be seen that the optimal shape of this test is the hexagon shape. [ABSTRACT FROM AUTHOR]

This study investigates the effect of high processing temperatures used in the medical syringe factory in Iraq on some rheological and morphological properties of polypropylene. Ten samples consisting of 50% virgin (pure) PP and 50% recycled PP were processed. The mold temperature was varied in the range of 190℃ to 210℃, while maintaining the pressure and secondary time at 78 bar and 0.5 seconds, respectively. The results showed that the density decreased by 45% as the injection temperature increased. In contrast, the Melt Flow Index (MFI) increased by 60% with rising injection temperatures. The results also indicated a severe effect of high processing temperatures on the samples, which was evident in the FTIR test, where the intensity of the peaks changed significantly compared to virgin PP. The DSC test revealed that the Tg value increased to 15.1℃ for recycled PP, compared to 9.8℃ for the virgin sample. [ABSTRACT FROM AUTHOR]

In the last two decades, a great interest has been focused on the creation and study of superhydrophobic nanomaterials based on the "lotus effect." This effect is caused by the heterogeneous wetting of rough surfaces, when the grooves of a rough surface are filled with air (vapor) and water contacts only with the tops of the protrusions. A drop forms a sphere on the surface and rolls down picking up dirt particles when the surface is slightly tilted. Diverse methods have been developed for producing such materials, and the potential of the ion-track technology (ITT) is being investigated. The goal of this work is to study the wettability of surface microtextures by the examples of two materials with different initial degrees of hydrophobicity. The ITT has been employed to obtain samples with maximum water contact angles of 140 ± 5° and 151 ± 5° by modifying the surfaces of polycarbonate and polypropylene films, respectively. It has been shown that such angles are characteristic of microtextures, for which surface fraction f that is in contact with a droplet is decreased to a range of 0 < f < 0.3. Materials with tilted microtextures have been obtained in order to increase the probability of droplet rolling down a material surface in a certain direction. In this case, the wettability becomes anisotropic. A droplet loses its spherical shape and is deformed in the direction of the tilt of needle-like surface elements. It has been found that the anisotropy of wettability is higher at a tilt angle of the texture elements of 45° than that at 30° (relative to the flat surface). [ABSTRACT FROM AUTHOR]

Bark plastic composite is a composite wood board consisting of a plastic matrix and bark in the form of powder or fibers as a filler. This research aimed to determine the influence of ratio and particle size on the characteristics of the composite made of Gmelina bark mixed with recycled polypropylene. Bark plastic composites were made with variations in powder: plastic ratio, namely 40:60% (P60), 30:70% (P70), 20:80% (P80), and 0:100% (P100), as well as variations in filler particle size, namely 40 to 60 mesh (M40), 60 to 80 mesh (M60), and 80 to 100 mesh (M80). Maleic anhydride (MAH) as a compatibilizer was added at 5% of the matrix's weight. The reference testing standards were JIS A 5908:2003 and SNI 03-2105-2006. In the physical property testing, including density, moisture content, water absorption, and thickness swelling, all boards with different treatments met the standards. In the modulus of elasticity (MOE) testing, none of the boards with different treatments met the standards, while in the internal bond testing, all boards with different treatments met the standards. As for the modulus of rupture (MOR) testing, hardness, and screw-holding power, some samples met both standards. The M40P80 treatment produced the best bark plastic composite. [ABSTRACT FROM AUTHOR]

The environmental-friendly intumescent flame retardant was constructed by the combination of piperazine pyrophosphate (PAPP) and chitosan (CS). The intumescent flame retardant polypropylene composites (IFR/PP) were prepared by melt blending. The flame retardants properties and mechanisms of IFR/PP were studied by methods such as oxygen index, cone calorimeter, thermogravimetric analysis and mechanical properties test. The results showed that when the total amount of expansion flame retardant was 30wt%, and the mass ratio of PAPP to CS was 5:1, the LOI value of IFR/PP was 35.5%, and UL-94 reached V-0 grade. The residue at 800 °C was 13.34wt%, the peak heat release rate (pHRR) was reduced from 1345.01 kW/m² to 83.04 kW/m², and the tensile strength was reduced by 39.9%. The SEM test results of residual carbon showed that the addition of CS promoted the formation of an expanded carbon layer, resulting in a denser and more uniform carbon layer during material combustion, which improved flame retardant property and smoke suppression ability. PAPP and CS have a good synergistic flame retardant effect. [ABSTRACT FROM AUTHOR]

Passive cooling techniques have gained widespread use in everyday life and various industries by utilizing sunlight reflection to cool objects without requiring additional energy input. Porous polymer materials possess the unique ability to provide both thermal insulation and solar reflection due to their inherent multiphase structure. In this study, we developed a porous polypropylene (PP) with a hierarchically structured surface layer using a simple and efficient solvent treatment method based on recrystallization. As a result, the porous structure and hierarchically structured surface significantly increase the solar reflectance from 11 to 86%. We found that by manipulating the recrystallization process and using reflective additives, solar reflectivity can be further improved. With the use of TiO2 and BaSO4 additives, a solar reflectance of 90% was achieved, while a solar reflectance of 93% was achieved with nucleating agents. In practical terms, these improvements result in significant temperature reductions in cooling performance tests compared to extruded PP sheets: 17, 19, and 22 °C for porous PP, porous PP/TiO2 or PP/BaSO4, and porous nucleated PP, respectively. The modification method introduced could help PP offer new possibilities for developing low-cost chemically resistant and thermally insulating layers in thermal management applications. [ABSTRACT FROM AUTHOR]