Phosphonium Containing UV-Curable Antimicrobials for the Coating and Fabrication of Common Touch Plastics

<p>The attachment and proliferation of antibiotic resistant, biofilm-forming bacteria to oft- handled material surfaces has emerged as a growing concern, particularly in the biomedical, healthcare and food packaging industries. The development of both biocide-releasing and tethered, immobilized biocide surface coatings has risen to meet this demand. While these surface coatings have demonstrated excellent antimicrobial efficacy, there are few examples of antimicrobial surfaces with long-term durability and efficacy. To that end, UV-curable phosphoniums bearing benzophenone anchors were synthesized with a variety of alkyl, aryl, and fluoroalkyl functional groups at phosphorus to probe their efficacy as thermally stable antimicrobial additives in plastics or as surface coatings. The surface topology and characteristics of these materials were studied to gain insight into the mechanism of antimicrobial activity of these materials. Additionally, general design principals for tailoring phosphoniums to function as both additives during injection molding processes and as UV-curable coatings are described, and evaluation against both Gram-negative and Gram-positive bacteria in both applications were carried out. Crucially, polypropylene (PP) materials containing phosphonium with a perfluoroalkyl substituent maintained the ability to kill biofilm-forming bacteria even after being subject to abrasion processes, demonstrating the potential to serve as a long-term antimicrobial material.</p>

A facile and versatile route to functional poly(propylene) surfaces via UV-curable coatings

In this work a suspect-screening approach was employed to assess the polymers and plastic additives of micro(nano)plastics (NPL/MPLs) of size ranges from the nm range to 20 μm present in seawater from the top 5 cm of the Mar Menor lagoon during two sampling campaigns (summer and winter), as well of other potentially adsorbed compounds onto the plastic particles surfaces and suspended material. The identification of NPL/MPLs has been based on characteristic Kendrick Mass Defect analysis for each polymer type in mass spectra. The applied methodology allowed to identify NPLs/MPLs of polystyrene (PS), polyethylene (PE), polyisoprene (PI), polybutadiene (PBD), polypropylene (PP), polyamides (PA), polyvinylchloride (PVC), n-isopropylacrylamide (PNIPAm), and polydimethylsiloxanes. In addition, PS, PE, PI, PBD, PP, PA, and PVC were confirmed with standards, and the equivalent concentrations were quantified. The results of this study showed that most frequently found compounds were PP, PE, PA and PNIPAm, while the compound found at higher concentrations was by far PP reaching the 9,303 ± 366 ng/mL in one of the samples. A total number of 135 chemical compounds were tentatively identified, 74 of them plastic additives and compounds used in the polymers manufacture or coming from the polymer’s decomposition. In relation to plastic additives, the more frequently tentatively identified compounds were plasticizers such as phthalates group; stabilizers such as antioxidants (e.g., distearyl 3,3′-thiodipropionate, 2,5-di-tert-butylhydroquinone), and UV filters as benzotriazoles. Several flame retardants of the group of phosphates were as well detected. The other compounds tentatively identified in the samples were pharmaceuticals, pesticides, food additives, flavors and natural products that were attached onto the plastic particles and particulate matter from surrounding waters. In regards to the seasonal variation, during the summer a major number of compounds were tentatively detected, while de concentrations of polymers were slightly higher in winter. The spatial distribution showed higher contamination in the southern part of the coastal lagoon.

The aim of the present paper is to incorporate two different waste plastic materials that is High-Density Polyethylene (HDPE) and Poly-Propylene (PP), were replaced with Fine Aggregate (FA) at a 10% by 2.5% increment. The widespread formation of HDPE and PP waste plastics has become a major environmental issue, endangering ecosystems and human health. Traditional disposal techniques, such as landfills and incineration, lead to pollution and resource depletion. Incorporating these polymers into concrete provides a long-term solution that reduces environmental effect while improving material qualities. The Different tests conducted are compressive strength (3, 7, 28 and 60 days) (150 × 150x150 mm), flexural strength (3, 7, 28 and 60 days) (100 × 100x500 mm), acid attack (28, 56 and 90 days) (100 × 100x100 mm), sulphate attack (28, 56 and 90 days) (100 × 100x100 mm), and thermal conductivity (180 mm dia x 20 mm thick). The compressive strengths of 40.52 MPa and 38.41 MPa for PP and HDPE material were observed in M30-grade concrete, respectively. Similarly, for M40-grade concrete, 43.6 MPa and 41.8 MPa are for PP and HDPE material, respectively. The optimum percentages of 5% and 7.5 for PP and HDPE material, respectively, can be replaced in concrete for flexural strength in both M30 and M40 grades. The least percentage loss in acid attack was observed at 28 days for both HDPE and PP material, but for 56 days and 90 days, the percentage loss of weight was significantly less (< 5%). The sulphate attack for both M30 and M40 grade concrete showed less than 10% percentage loss in weight after 90 days. Thermal conductivity (k) was also reduced by 30–35% for both HDPE and PP material, with 10% replacement in concrete for M30 and M40 grades. The use of Waste HDPE and PP material can be used to improve the mechanical, durability & thermal property of M30 and M40 grade concrete under controlled conditions.

Pressure-sensitive adhesives based on acrylated epoxidized linseed oil: A computational approach

Certain agricultural plastics, i.e., mulching films, are generally considered as potent sources of micro- and nanoplastics (MNPs), due to their direct application on soil and waste mishandling. During the synthesis and fabrication of such agricultural plastics, it is necessary to use chemicals, the so-called plastic additives (PAs), improving the physicochemical properties of the final polymeric product. However, since PAs are loosely bound on the polymer matrix, they can potentially leach into the soil environment with unidentified effects. Clearly, to monitor the fate of PAs in the terrestrial ecosystem, it is necessary to develop accurate, sensitive and robust analytical methods. To this end, a comprehensive analytical strategy was developed for monitoring 16 PAs with diverse physicochemical properties (partition coefficient; −3 < logP<19) in soil samples using ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). For this purpose, two different extraction procedures were developed, namely, a single step ultrasound-assisted extraction (UAE) using ethyl acetate or an aqueous solution of methanol and a binary extraction, combining Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) and UAE principles with n-hexane as the extractant. Interestingly, within the sample preparation investigation, we identified in-lab contamination sources of PAs, e.g., centrifuge tubes or microfilters. Such consumables are made of plastic contaminating the procedural blanks and omitting their use was necessary to acquire satisfactory analytical performance. In detail, method validation was performed for 16 compounds achieving recoveries mainly in the range 70–120 %, repeatability (expressed as relative standard deviation, RSD %) < 20 % and limits of quantification (LOQs) ranging between 0.2 and 20 ng/g dry weight (dw). Importantly, the presented strategies are added to the very limited available for PA determination in soil, a topical issue with a significant and rather understudied impact on agriculture.

5 - Fabrication of high-barrier plastics and its application in food packaging

Mechanical behavior prediction of PPR and HDPE polymers through newly developed nonlinear damage-reliability models

Open AccessCCS ChemistryRESEARCH ARTICLE10 May 2022Visualization of Macrophase Separation and Transformation in Immiscible Polymer Blends Zhiyuan Wu, Chunyu Zhang, Youliang Zhu, Zhongyuan Lu, Heng Liu, Bin Xu, Xuequan Zhang and Wenjing Tian Zhiyuan Wu State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin 130012 , Chunyu Zhang *Corresponding authors: E-mail Address: [email protected] E-mail Address: [email protected] Key Laboratory of Rubber-Plastics, Ministry of Education, Shandong Provincial Key Laboratory of Rubber-Plastics, School of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042 , Youliang Zhu State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin 130012 , Zhongyuan Lu State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin 130012 , Heng Liu Key Laboratory of Rubber-Plastics, Ministry of Education, Shandong Provincial Key Laboratory of Rubber-Plastics, School of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042 , Bin Xu State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin 130012 , Xuequan Zhang Key Laboratory of Rubber-Plastics, Ministry of Education, Shandong Provincial Key Laboratory of Rubber-Plastics, School of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042 and Wenjing Tian *Corresponding authors: E-mail Address: [email protected] E-mail Address: [email protected] State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, Jilin 130012 https://doi.org/10.31635/ccschem.022.202101726 SectionsSupplemental MaterialAboutAbstractPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail Identification and visualization of phase structures inside polymer blends are of critical importance in the understanding of their intrinsic structure and dynamics. However, the direct optical observation of the individual component phase in a dense bulk material poses a significant challenge. Herein, three-dimensional fluorescence imaging of phase separation and real-time visualization of phase transformation in immiscible polymer blends of polypropylene and polystyrene is realized through multiphoton laser scanning microscopy. Owing to the specific fluorescence behavior of the cyanostyrene derivative 2-(4-bromophenyl)-3-(4-(4-(diphenylamino)styryl)phenyl)fumaronitrile, the high-contrast imaging of the macrophase of the component polymer in two and three dimensions with a maximum depth of 140 μm and a high signal-to-noise ratio of 300 can be achieved. Detailed spectroscopic and structural studies reveal that the distinctive fluorescence features of each phase domain should originate from the formation of a completely different aggregate between probes and component polymer. Furthermore, visualizations of the internal morphology deformation and macrophase transformation were realized by employing a stretched dumbbell sample under constant tension. Download figure Download PowerPoint Introduction Polymer blends can provide excellent performance that can be achieved by combining various polymers with distinctive properties into a single material in many ways.1,2 These multi-component systems typically lead to a wide range of phase behaviors that directly influence the associated physical properties and play a crucial role in the final application.3 Thus, identifying the spatial structure of their individual phases is critical to understanding the relationships among the formation, structure, dynamics, and functionality of blend materials. Most polymer blends are immiscible, that is, each component phase usually separates into distinct, macroscopic domains during the mixing process, termed as macrophase-separated structures, which greatly affects the blend properties.4 For example, a co-continuous structure can lead to maximum contributions of stiffness, hardness, and impact properties of each component simultaneously, which can then be used in a variety of applications, such as electrically conductive blends and tissue scaffolds.5 A significant complication in blending is that the resulting structures are three-dimensional (3D) and have an interpenetrating anisotropic structure. Furthermore, the macrophase-separated domains and structures are usually formed and observed on the micrometer scale,6–9 which makes it difficult to clearly identify the intrinsic structures of phase behavior, especially for the structures inside the polymer matrix. Some analytical techniques,5,10,11 such as transmission electron microscopy,12 scanning electron microscopy (SEM),13 and atomic force microscopy,14 are used to characterize the surface topography, size, and distribution of the dispersed phase in polymer blends. Although these methods offer excellent spatial resolution, they are usually confined to the material surfaces or cross-sections that require an invasive sample preparation process.15,16 The lack of the third dimension leads to a misinterpretation of the true phase structure.17–19 More complicated morphologies will usually result in a less convincing interpretation of the surface images. Moreover, they do not directly provide intuitive insight into the morphologies and are unable to provide a representation of these internal complex structures.20 Therefore, the development of microscopes that are capable of 3D images for internal complex structures is anticipated. Recent advances in fluorescence-based techniques have emerged as a powerful tool to characterize morphologies and facilitate a 3D visualization of the exact morphology.21–30 Lopez-Barron and Macosko31 characterized the interface between the two phases of an immiscible polymer blend made of fluorescently-labeled polystyrene (PS) and styrene-ran-acrylonitrile copolymer by laser scanning confocal microscopy. Tang et al.32 observed the macrodispersion of montmorillonite fillers labeled with tetraphenylethene in a polymer matrix. However, visualization and precise localization of individual phase domains in a densely packed polymer mixture, especially for the internal phase structures, are still rare. Several factors limit the performance of current fluorescence microscopy to image macrophase structures of polymer blends, such as difficult or even impossible identification of different polymer species, an inability to distinguish the localization of phase-separated domains inside the sample, or unsatisfactory fluorescence imaging efficiency and contrast.33–38 These restrictions mainly involve the emission behavior of fluorescent probes in the polymer mixture, which ultimately influences the final imaging resolution, signal-to-noise ratio, and the visualization of an individual polymer within the bulk blends. Therefore, a direct 3D imaging technique for polymer blends without any invasive processes remains a significant challenge but would provide valuable information about both their intrinsic structures and dynamics. We have addressed the above challenge and developed a specific strategy of manipulating dye aggregates to identify polymer domains with or without phenyl moieties, where different aggregation pathways lead to two distinct emission properties of a specific label-free fluorescent probe, 2-(4-bromophenyl)-3-(4-(4-(diphenylamino)styryl)phenyl)fumaronitrile (TB). By exploiting TB in a way to selectively light up the target polymer, we have demonstrated ultrafast and non-invasive imaging of immiscible polymer blends composed of polypropylene (PP) and PS using a multiphoton fluorescence imaging technique (multiphoton laser scanning microscopy, MLSM). The distinct fluorescence of polymer domains with or without phenyl moieties allows us to visualize 3D structures of individual phases inside the polymer mixtures. This excellent depth resolution can clearly observe a more accurate ellipsoid radius and the transformation from a co-continuous phase to a sea-island phase under different annealing rates. Furthermore, we can also track the phase distribution in a stretchable dumbbell sample of PS/PP under constant tension in real time. The "invisible" information relative to the internal morphology deformation in the polymer specimens is transformed to visible fluorescent signals, which provides an essential insight into the relationship between the microstructure and mechanical properties of the polymer blends. Experimental Methods All-atom molecular dynamics simulation of the TB-doped PS films and TB-doped PP films An all-atom molecular dynamics (MD) simulation system consists of four TB molecules and 20 PS or PP chains with a length of 50 repeating units for each. Simulations were carried out using the Forcite module of the Materials Studio (Accelrys Inc., San Diego, CA, United States) with COMPASSII force field. The composite structure was equilibrated for 1 ns to fully mix the TB molecule with PS or PP chains by the simulation under the NPT ensemble at room temperature and 1 bar pressure. General preparation procedure of TB-doped polymer films Polymer and TB stock solutions were prepared by dissolving 1 g of polymer sample in 100 mL toluene and dissolving 0.001 g of TB in 2 mL toluene, respectively. Polymer blend solution with a PP mass fraction of 80% were prepared by mixing 0.4 mL of PP solution and 0.1 mL of PS solution. Afterward, 0.1 mL TB solution was mixed with 0.5 mL of as-prepared polymer solution under ultrasonication for about 2 h, generating a homogeneous solution with a polymer concentration of 10 mg/mL and 1.0 wt % content of TB. Uniform thin films of TB-doped polymers were fabricated by droplet coating the mixed solutions of TB and polymer blends onto quartz plates. The samples was kept at 180 °C for 10 min to volatilize toluene, and then the temperature was reduced to room temperature at rates of 1, 10, and 50 °C/min, respectively. General preparation procedure of TB-doped PS/PP bulk First, we mixed the TB (1.0 wt %) with PS and PP in a WLG10G twin-screw extruder (Shanghai Xinshuo Precision Machinery Co., Ltd., Shanghai, China) at 180 °C extruder temperature and 60 r/min screw speed. Tensile test specimens with dimensions of 75 × 10 × 2 mm made of TB/PS/PP were produced by injection molding, conducted by a WZS10D injection molding machine (Shanghai Xinshuo Precision Machinery Co., Ltd., Shanghai, China) at 180 °C injection temperature, 10 MPa packing pressure, and 5 s packing time. Results and Discussion Developing a specific fluorescence probe for polymer blends Our strategy to visualize and analyze the structures of immiscible polymer blends depends on the aggregation of the fluorescent probe, which differs from conventional methods that often need to label the polymer with a fluorescent probe through a complicated synthetic procedure. We synthesized a specific fluorescent probe TB ( Supporting Information Figures S1–S3) that can boost its emission when doping in polymers containing a benzene ring and can totally quench its emission in other polymers. Consequently, an appropriate binary polymer blend, containing benzene-based PS and its immiscible pair PP, is expected to serve as a potential imaging target by simply doping with the fluorescent probe TB (Figure 1a). The experimental samples can be prepared by using simple solution-processed methods, such as spin coating or droplet coating, in which 1 wt % TB is doped into the polymer. Figure 1 | Investigating photophysical properties of TB. (a) Luminous mechanism of the TB (1.0 wt %) doped in PS and PP and molecular structures of the polymers (PS and PP) and fluorescent probe (TB). (b) UV–vis absorption and (c) PL emission spectra (excitation wavelength: 365 nm) of the TB in THF solution, TB films, 1.0 wt % TB-doped PS films and 1.0 wt % TB-doped PP films. (d) Free energy of mixing TB with PS, PP using melting point depression measurements. Download figure Download PowerPoint The emission behaviors of TB in both PS and PP matrices were initially investigated by steady-state spectroscopy. As expected, the TB-doped PS films exhibited bright red fluorescence, whereas the TB-doped PP films and TB films exhibited almost no emission. The PL spectrum of TB-doped PS films showed a strong emission band peak at 614 nm, where the photoluminescence quantum yield (ΦF) was as high as 34%. In contrast, TB-doped PP films or pure TB films exhibited almost no emission and their PL spectra were a straight line along the bottom (Figure 1c). Furthermore, we found that TB films show an obviously red-shifted absorption band compared with that of TB in tetrahydrofuran (THF) solution, indicating that the existence of strong intermolecular interactions leads to aggregate formation in TB films, as shown in Figure 1b. Importantly, when doping PS and PP with TB, the absorption band of the TB-doped PS films showed a red-shift compared with the TB-doped PP films. These observations suggested that TB probably exhibits different intermolecular interactions with a PS or PP polymer chain, because the optical properties of the dye molecules strongly depend on the aggregate structure or packing arrangement. To gain further insight into the interactions between TB and polymer in a matrix, the compatibility of TB with the polymer was evaluated by the Flory–Huggins interaction parameter (χ), whose value can be derived from the melting point of TB in the presence of a polymer (TMmix). The melting point of the TB-doped PS or TB-doped PP mixture with different mass fractions was performed by differential scanning calorimetry. As shown in Supporting Information Figure S4, TB showed varying degrees of melting point depression in the PS and PP mixture. Thus, as shown in Figure 1d, we can obtain the values of the interaction parameter of TB with different polymers through Flory–Huggins lattice theory.39,40 In the mixture of TB and PS, the interaction parameter is −0.11, which indicates that they are miscible. The negative interaction parameter reflects a great thermodynamic driving force for mixing TB with PS, which suggests TB has good dispersion in the PS matrix and tends to form an isolated state. In contrast, the mixture of TB and PP results in a largely altered interaction parameter of 0.65. The highly positive value of the interaction parameter indicates that TB and PP are immiscible, and the large difference between the interaction parameters suggests that TB undergoes a different assembly process when mixed with PS and PP. It is worth noting that TB molecules possess a large dipole moment because of the asymmetric geometric and strong intramolecular charge transfer state, which usually leads to the formation of compact packing and strong intermolecular interactions. Indeed, strong π–π interactions and a closed packed structure are observed for the TB crystal ( Supporting Information Figure S5), which also exhibits no emission similar to its films ( Supporting Information Figure S6a). These findings indicate that TB would present a different aggregate structure in a PS and PP polymer matrix, resulting in distinct emission behavior. Additionally, to explore the fluorescence properties of TB-doped polymers with or without phenyl moieties, a variety of polymers with and without phenyl moieties were chosen, such as PS, poly-a-methyl styrene (PAMS), styrene butadiene styrene block copolymer (SBS), polyethersulfone (PES), PP, polyvinyl pyrrolidone (PVP), polyetherpolyol (PMPO/POP), and polycaprolactone (PCL). As shown in Supporting Information Figure S6, TB exhibited strong emission in PS, PAMS, SBS, and PES, but showed weak emission in PP, PVP, PMPO, and PCL. This suggests that TB can serve as a unique probe for the visualization of phase separation of biphasic blend polymers with and without phenyl moieties. We further investigated the excited-state dynamics of TB in a PS and PP polymer matrix. Time-resolved fluorescence spectra of TB shown in Supporting Information Figure S6b reveal a significantly increased fluorescence lifetime (τFL) of TB-doped PS films (5.01 ns) compared with that of TB-doped PP films (1.38 ns), as well as TB films (2.65 ns). Furthermore, a long fluorescence lifetime was also observed in TB-doped rigid polymers, as listed Supporting Information Table S1. Because the PL quantum yield ΦF equals the product of τFL and the radiative deactivation rate (kr), kr and the non-radiative deactivation rate (knr) can be approximately estimated ( Supporting Information Table S1). Compared with TB-doped PP films, there is one order of magnitude increase of kr in TB-doped PS films, while knr decreases to one-sixth. This shows that the fluorescence transition is favorable in TB-doped PS films but inhibited in TB-doped PP films. It is worth noting that TB has no emission in diluted THF solution but exhibits boosted emission at 77 K ( Supporting Information Figure S7). The frozen solution provides a rigid environment to fix the isolated TB molecules and restrict the intramolecular motions, which results in enhanced emissions compared with that in solution at room temperature. This is in good agreement with the strong emission observed when TB is doped into the PS matrix, where PS is analogous to a solid solution. However, TB films also show a low kr similar to the TB-doped PP film, which suggests that TB probably forms aggregates to cause emission quenching. Excited state dynamics of TB/PS and TB/PP polymer mixtures To explore the origin of the distinctive fluorescence behavior of TB in various aggregate states, we carried out ultrafast transient absorption (TA) spectroscopy to study the internal excited-state dynamics. Femtosecond-resolved TA spectra of TB are shown in Figures 2a, 2b, 2d, and 2e. After excitation, the characteristic excited-state absorption (ESA) bands at 500–750 nm were observed in THF solution within a few ps. Fast intramolecular non-radiative processes, including structural evolution accompanied by vibration and rotation, can dissipate the excited-state energy of TB on the sub-ps and ps scales. The significant changes in ESA within 2 ps is likely due to the configurational evolution after photoexcitation ( Supporting Information Figure S8). In sharp contrast, the characteristic stimulated emission (SE) bands at 580–610 nm overlapping with the ESA bands at 610–780 nm were observed in TB-doped PS films. Notably, a constant decrease at the SE band was observed, which is in good agreement with its PL spectrum at 625 nm (Figure 2a) and should result from the radiative S1–S0 decay. This spectral evidence indicates that a large number of excitons are deactivated through the radiative pathway, which is consistent with a high radiative deactivation rate. The all-atom MD simulations predict the dispersed state of TB in different polymer matrixes. As indicated in Figure 2c, TB was mono-dispersed in the PS matrix and tended to an isolated state owing to the good compatibility with PS. Consequently, the radiative transition of excited TB can be predominant when TB is mono-dispersed in a rigid PS matrix and intramolecular vibration and rotation are suppressed. Figure 2 | Excited state dynamics of TB in different states. TA spectra of (a) TB-doped PS films, (b) TB-doped PP films, TB in (c) THF and (d) TB films. Excitation: 400 nm, probe light: 450–780 nm. Snapshot of the all-atom MD simulations of (e) TB/PS films and (f) TB/PP films. Download figure Download PowerPoint Although the intramolecular vibration and rotation are greatly suppressed in the solid state, excimers are likely to form in TB films upon excitation, owing to the molecular stacking and intrinsic D–A structure of TB. A "dark" excited state can be formed within 1 ps, as evidenced by the gradually increasing ESA, which then undergoes a non-radiative pathway ( Supporting Information Figure S9). More importantly, an obvious change of the ESA in TB-doped PP films was also observed within 25 ps ( Supporting Information Figure S10), which lagged compared with that of TB in solution. This may originate from a slow configurational evolution after photoexcitation, where the intramolecular motions are not fully restricted by the PP matrix. Similar to TB films, the gradually increased and blue-shifted ESA indicated that the radiative transition of excited TB was inhibited, because a molecular aggregate was formed following the initial structural evolution. These findings imply that the "dark" excited state should originate from the formation of a unique aggregate of TB in the PP matrix, which agrees with the closed stacking of TB molecules from MD simulations (Figure 2f). 3D visualization of the phase separation of PS/PP films by MLSM Owing to the unique photophysical properties of TB doped in different polymer matrixes, we explored the potential application in directly imaging the morphologies of polymer blends by fluorescence microscopy. For this purpose, PS and PP without any fluorescent probe labels were chosen as binary immiscible polymer pairs, and TB served as the fluorescence probe with a low doping content of 1%. The blend films underwent a simple mixing process with different annealing treatments to obtain various phase-separated structures. As shown in Supporting Information Figure S11, a surface image of a phase-separated structure between the PS and PP phase domains was clearly observed by fluorescence microscopy, where the PS domains showed strong emission and the PP domains exhibited no fluorescence. This indicates that TB exhibits distinct fluorescence properties in different phase domains when doping in a PP/PS blend mixture. The results imply that the assembly processes of TB with PS and PP in the blend mixture are independent of each other, and the emission behavior is identical to that from doping with the single polymer. As shown in Supporting Information Figure S12, TB/PS films with different TB ratios had strong fluorescence emission while the fluorescence of TB/PP films was always weak. It means that TB can keep the same fluorescent when different mass fractions of TB are doped in polymers. the significant difference of emission in blends, we to 3D visualization of the phase-separated structure inside blends by It is worth noting that TB not exhibits a unique emission behavior but also highly optical Our study demonstrated that TB shows a large absorption in its aggregate state, which is for fluorescence under ( Supporting Information Figure More importantly, the assembly process with PS the radiative transition of TB, which results in a high photoluminescence quantum yield of a TB-doped PS mixture. These of the unique features of TB are critical for the high imaging resolution and of TB-doped polymer blends. Figure MLSM images of PS/PP binary polymer blends, where the blend was prepared by simply mixing in toluene by droplet coating the mixed solutions of TB and polymers onto quartz plates. The samples were kept at 180 °C for 10 min to volatilize the toluene and then the temperature was to room temperature at a rate of 1 with of nm were on the surface of the films through an The imaging for each was approximately s with in the the image shows a phase-separated structure of polymer blends, in which the red the PS phase domain and the to the PP phase The between the two is well and was to identify one from the The strong red from the PS domain is to the fluorescence of TB, in sharp contrast, no from the PP domain was owing to the quenching. In to these we 3D images the technique and The images clearly show two distinct red and in which the PS and PP domains are from each other, even in the the ratio of and maximum imaging depth of μm were achieved in the blends. Compared with fluorescence microscopy, there was a of the by MLSM ( Supporting Information Figure which to the of fluorescence and a high Owing to imaging of the blend, the isolated structures with different of the PS domain were from the scanning images of each at 10 Notably, we were to directly observe the true of PS from the of the fluorescence where of the PS with a maximum of approximately 25 μm are from one we found that of PS domains have into one observed in the depth of whereas they are completely in of 10 and 20 These observations are consistent with that that of the phase can to form through the In other the and process of the isolated PS phase probably through the PP Figure | 3D visualization of the phase separation of TB/PS/PP films. (a) of 3D fluorescence imaging of TB/PS/PP films from a depth of (b) of imaging of TB/PS/PP films. The TB/PS/PP films 10 μm in the range of PS imaging at a depth of 10 μm 20 μm and μm (e) of PS Download figure Download PowerPoint from other we the imaging of binary immiscible polymer blends fluorescent probes by We directly observed an and sharp 3D image of the complicated morphologies inside blends owing to excellent and depth resolution, which is difficult to by conventional and optical microscopy of the of annealing rate on the phase separation of PS/PP films by MLSM MLSM imaging allows us to directly the properties of phase separation in immiscible polymer blends. to the phase separation of polymer blends is a process, which suggests that the annealing process will have a significant impact on the phase-separated structure. Figure shows the images of TB-doped PS/PP blends with different annealing rates. The images were through MLSM with in the ( Supporting Information Figures The co-continuous structures in blends were observed when the temperature at a rate of 50 (Figure and Supporting Information where the PS and PP showed 3D spatial interpenetrating and structures. rates to 10 °C/min, we found that the or are not fully and there are PS domains inside the blend matrix as shown in Figure and Supporting Information By further the rate to 1 °C/min, the droplet or isolated of PS were well dispersed in the blend matrix, and each droplet was completely

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

In the present paper two different plastic materials High Density Polyethylene (HDPE) and Polypropylene (PP) was replaced with fine aggregate (FA) till 10% by 2.5% increment. Different test such as compressive strength (3, 7, 28 &amp; 60 days) (150x150x150mm), flexural strength (3, 7, 28 &amp; 60 days) (100x100x500mm), acid attack (28, 56 &amp; 90 days)(100x100x100mm), sulphate attack (28, 56 &amp; 90 days)(100x100x100mm), thermal conductivity (180mm dia x 20mm thick). The compressive strength of 40.52MPa and 38.41Mpa for PP and HDPE material was observed in M30 grade concrete respectively. Similarly, for M40 grade concrete 43.6MPa and 41.8MPa for PP and HDPE material respectively. The optimum percentage of 5% and 7.5 for PP and HDPE material respectively can be replaced in concrete for flexural strength for both M30 and M40 grade. The least percentage loss in acid attack was observed at 28 days for both HDPE and PP material but for 56days and 90 days the percentage loss of weight was significantly less (&lt; 5%). The sulphate attack for both M30 and M40 grade concrete showed less than 10% percentage loss in weight till 90 days. Thermal conductivity (k) was also reduced by 30–35% for both HDPE and PP material till 10% replacement in concrete for M30 and M40 grade.

ABSTRACTIn this research, polypropylene (PP) fabrics were modified with two types of ionic liquids, 1-ethyl-2,3-dimethylimidazolium ethyl sulfate (EIL) (2, 6, 10 wt%/v in ethanol) and methyl-tri-n-butylammonium methyl sulfate (10, 15, 20 wt%/v in ethanol) at different concentrations. PP fabrics were pre-treated with chromic acid solutions for improving surface functionalization. The pre-treatment led to increases in moisture content, hydrogen bonding related absorption peaks and surface roughness of the PP. The pre-treatment changed surface resistivity from 7.1 × 1010 to 4.1 × 1013 ohm/sq. With the given set up, surface resistivities of the PP decreased with the ionic liquids for short – and long-term periods. Increasing the concentration of the ionic liquids can be considered as an efficient way to reduce the surface resistivity of PP. Thermal conductivity of the PP rose up significantly after BIL and EIL modification of PP. Crystalline structure and thermal stability of the PP altered after modification of PP. It was observed that a coating layer formed on surface of the fabric and in the gaps of the yarns of PP with modification. This cost-effective and environmentally-friendly method can be used as an alternative way for improving conductivity of PP fabrics generally characterized by their high surface resistivity.

Study of the effect of the addition of plasticizers on the physical properties of biodegradable films based on kefiran for potential application as food packaging

Mechanical properties of plasma-irradiated and surface-coated wood plastic composites (WPCs) have been investigated in this paper. WPCs were developed by injection molding technique using wood fiber (WF) as reinforcement and polypropylene (PP) as matrix. The short, discontinuous WF was compounded with thermoplastic PP at varying weight fractions of 0 wt%, 25 wt% (WP25), and 50 wt% (WP50) to yield tensile test specimens in accordance with JIS K7139-A32 standards. Subsequently, plasma treatment was performed on the test-pieces, followed by surface coating by immersion in acrylic resin liquid containing homogeneously dispersed TEMPO-oxidized cellulose nanofibers (CNF). The results indicate an increase in surface roughness after plasma irradiation, but surface coating of the specimens with acrylic paint and CNF decreased their surface roughness by ∼50% in comparison to the untreated specimens. Plasma treatment and surface coating also increased the tensile strength of neat PP, WP25 and WP50 specimens by 5.4–7.1%, 3.5–3.7% and 3.0–3.6%, respectively, whereas their fracture strains tended to decrease. Compared to the untreated specimens, the surface-coated specimens generally displayed higher tensile strength. This finding is a corroboration that the observed increase in strength is highly contingent on the adhesion between the specimen surface and the coating layer than on the improvement in surface roughness. Thus, it is inferable that surface coating could be of great importance in enhancing the mechanical performance of WPCs.

Effects of cooking methods on microplastics in dried shellfish