Absorption Of Polymers Research Articles

Investigation of amyl acetate sorption impact on high‐density polyethylene bottle properties

AbstractThermoplastics based on polyolefins, including polypropylene, high‐density polyethylene and low‐density polyethylene, are extensively utilized across various packaging sectors. The selection of these materials for specific applications is influenced by multiple factors, such as the polymer's absorption characteristics and the impact on its mechanical properties when in contact with the packaged product. This study presents an experimental methodology designed to simulate the effects of absorption on the macroscopic and microscopic properties of high‐density polyethylene bottles in contact with amyl acetate. Macroscopic degradation was evaluated by modeling mechanical damage using unified theory and the energy method. Analytical techniques such as gravimetric analysis, scanning electron microscopy and Fourier transform infrared spectrometry were employed. The findings of this research provide valuable insights for suppliers and industries to experimentally determine the usability and safety intervals of plastic packaging through comprehensive macroscopic and microscopic analyses within relatively short timescales. © 2024 Society of Chemical Industry.

Absorption and Release mechanism of superabsorbent polymers and its impact on shrinkage and durability of internally cured concrete – A review

Superabsorbent polymers (SAP) are considered as a promising assortment of chemical admixtures which present novel prospects for influencing the properties of cementitious materials in the fresh, setting, and hardened states. However, the diversity of commercial SAP, especially in terms of monomers, crosslinking agents, and synthesis methods, still poses many obstacles in their large-scale application. Therefore, this review aims to shed light on intrinsic absorption and release mechanism of various SAP and its impact on rheological properties, mechanical properties, shrinkage properties, and durability for cementitious materials. Our research findings indicate significant differences in the water absorption and release mechanisms between ionic and non-ionic SAP. The swelling of non-ionic SAP is dependent on the osmotic pressure formed between the polymer network and the solution. In contrast, ionic SAP not only exhibits osmotic properties but also generates charged hydrophilic groups in solution, which is a crucial factor contributing to polymer swelling. The water absorption characteristics of SAP facilitate the regulation of early cement matrix hydration and ensure the long-term stability of the concrete structure. These attributes are crucial for maintaining stable development in cement hydration and ensuring the overall structural integrity over time. The knowledge gleaned from this review offers a robust framework for the further research work on SAP and serves as support for practical application of internally cured concrete in construction engineering that need to withstand challenging environmental conditions.

Performance of Combined Woven Roving and Mat Glass-Fiber Reinforced Polymer Composites Under Absorption Tower Lifting Loads.

This study investigates the structural integrity of a glass-fiber reinforced polymer absorption tower during lifting operations, evaluating factors of safety and stress distribution for both horizontal and vertical scenarios. A key focus is the comparative analysis of surface and volumetric meshing techniques in finite element modeling. Results demonstrate that surface models achieve comparable stress predictions to computationally intensive volumetric models, significantly reducing computational demands without compromising accuracy. For instance, stress at the flange edge with holes was accurately captured using a surface model with 5675 elements (12.79 MPa), yielding similar results to a volumetric model requiring over 94,000 elements (13.37 MPa). Similar computational efficiency and agreement between modeling approaches were observed at the packing support ring-shell joint. Finite element analysis employing Hashin's failure criterion, informed by industry-standard experimental data, revealed safety factors ranging from 1.9 to 2.5 for horizontal lifting and four for vertical lifting. These safety factors indicate sufficient margins for safe operation. While these findings support the feasibility of both lifting methods, further investigation is recommended to address the lower safety factors observed in specific horizontal lifting scenarios. A comprehensive assessment incorporating industry standards, dynamic load effects, and potential mitigation strategies is crucial to ensure the long-term structural integrity of the GFRP absorption tower.

Prediction and investigation of water repeated absorption and release properties of superabsorbent polymers during the dry-wet cycles in different solutions

Superabsorbent polymers (SAP) with a three-dimensional cross-linked network structure are used in the concrete field due to their good water absorption and water retention properties. The changes of its repeated water absorption and release properties have an important impact on crack healing, but there is still a lack of relevant research. This study mainly uses the tea-bag method to explore the repeated water absorption and release behavior of sodium polyacrylate and polyacrylic acid-acrylamide copolymers in deionized water, cement filtrate, and saturated calcium hydroxide solution. The quantitative analysis of the change in the peak area of the water-absorbing functional group was performed by fourier transform infrared spectroscopy. The morphology and elements of SAP under different dry-wet cycles were analyzed by scanning electron microscope-energy spectrum analysis. The repeated swelling behavior of SAP was predicted using the classical models. The results showed that the repeated water absorption performance of SAP gradually decreased with the increase of the number of wet-dry cycles. The slope of the curve for the second-order equation gradually increases, and the peak area corresponding to the carboxyl functional group also gradually increases. And the rate and amount of water release gradually increase. For sodium polyacrylate, with the increase in the number of wet-dry- cycles, the increase in the content of calcium, magnesium, and aluminum elements is accompanied by a significant decrease in the content of sodium elements. In contrast, the calcium content on the surface of polyacrylic acid-acrylamide copolymer increased, but the sodium content only slightly decreased.

Structural effects on heat capacity, moisture absorption and thermal expansion of epoxy-novolac polymers

Today epoxy novolac resins are of great interest for the aerospace industry. Thermal properties of the polymer matrix, as well as the effect of moisture on the characteristics of polymer composite materials (PCM) under thermomechanical impacts, are critical tasks in creating dimensionally stable structures operating in a wide temperature range. Particularly, thermal and moisture expansion as well as heat capacity are important parameters for evaluating of polymer matrices and modeling their properties. In this work, polymers based on a number of epoxy novolac resins with aromatic amine hardener were studied. The values of the crosslink density were experimentally determined, and a comparative analysis of thermal expansion and heat capacity for epoxy polymers with different crosslink density was carried out. The dependence of thermophysical properties on polymer crosslinking density is shown, both in glass and highly elastic states. Additionally, this study analyzes the process of water sorption by polymers and the coefficient of moisture expansion. The most significant dependence of the diffusion coefficient was observed with coefficient of moisture expansion.

Determination of critical properties of orange peel for a polymer reinforcement material

Accurately determining the critical properties of orange peels ensures composite engineers can successfully monitor and control in-service composite failures. However, the current approaches to property determination are deficient, lack critical analysis, and are not wide-ranging. Thus, they fail to accurately establish the important properties of orange peels. To overcome this challenge, this article establishes the compressive strength, heat absorption, and electrical conductivity of an orange peel polymer to understand the behaviour of the material in lightweight composite applications. Three experimental sets were used to determine the three mentioned properties. The results obtained showed that the average heat energy absorbed by the samples of collected orange peels in 28 poly bags was 79.32 J. The highest and lowest heat absorbed by the samples was found to be 162.03 and 11.08 J, respectively. The average electrical conductivity was measured at 0.025σwhile the average resistance, length, and surface area of 20 orange peel samples were found to be 27.24Ω, 2.92 cm, and 7.02 cm2, respectively. The resistance of the orange peels had the greatest influence on their electrical conductivity. Lastly, the compressive shear strengths of the 0.300, 0.425, and 0.600-mm orange peel particulates were found to be 41.86, 14.82, and 9.58 kN/m2, respectively. With this information, composite design engineers using orange peel reinforcements could improve their design accuracies and extend in-service composite lives.

Vanadium speciation using magnetic multi-walled carbon nanotubes coated with ion-imprinted polymer and electrothermal atomic absorption spectrometry

ABSTRACT For selective extraction of vanadium (V) from water and food samples, ion-imprinted polymer was synthesised on magnetic multi-walled carbon nanotubes. For this purpose, the complex of V(V)-8-hydroxyquinoline, 4-vinylpyridine, ethylene glycol dimethacrylate, and magnetic multi-walled carbon nanotubes were used as the template of V(V), functional monomer, cross-linker, and the core, respectively. The prepared sorbent was characterised by FTIR spectroscopy, scanning electron microscopy, X-ray diffraction, energy-dispersion X-ray, and vibrating sample magnetometer. The extracted vanadium (V) was assessed by electrothermal atomic absorption spectrometry. The total vanadium in the solution was extracted and determined after oxidation of V(IV) to V(V) by hydrogen peroxide. Under optimised conditions, limits of detection and quantification of 2.9, and 10.0 ng L−1 were obtained, respectively. The maximum capacity of sorbent was 44.1 mg g−1. The method was successfully employed for the extraction and quantification of vanadium species in different water samples and total vanadium in food samples.

Trenched microwave resonator integrated with porous PDMS for detection and classification of VOCs with enhanced performance

Microwave resonators combined with polymer absorption layers are widely used in volatile organic compound (VOC) detection based on their variable resonant frequencies. However, the response time is limited due to the polymer’s slow volumetric absorption of VOC molecules. By constructing a porous structure in Polydimethylsiloxane (PDMS), resulting in reduced the response time to as short as 71.1%. To mitigate the sensitivity decline caused by the porous PDMS, a trenched-substrate complementary split-ring resonator (CSRR) is proposed for enhancing the interaction between the electromagnetic fields (EMFs) and the porous PDMS with VOCs. The removal of the substrate beneath CSRR’s sensing region enhances the effective EMF, increasing frequency and amplitude sensitivities up to 175.5% and 137.8%, respectively. Responses to four common VOCs by the sensor show a maximum sensitivity of 217 Hz/ppm and a minimum limit of detection of 295 ppm. Additionally, resonant parameters and extracted lumped parameters are utilized to establish two decision-tree-based VOC classification models, achieving high accuracies of 98.71% and 99.59%, respectively. And the latter one fully utilizing responses throughout the swept band, proves superior in identifying similar substances. This sensor technology helps promote the sensitive detection and accurate classification of diverse VOCs.

Influence of Chromophore Packing on Multiphoton Absorption in Carbazole-Based Pillar-Layered Coordination Polymers

Influence of Chromophore Packing on Multiphoton Absorption in Carbazole-Based Pillar-Layered Coordination Polymers

Cross-coupling and dehalogenation reactions of novel π-conjugated polymers bearing high-soluble coumarin unit in the main chain and their acid-base responsive fluorescence

A highly soluble coumarin monomer, 3,7-dibromo-4-octyloxycoumarin, was developed as the novel building block for π−conjugated polymers. Sonogashira coupling reaction, dehalogenation reaction, and Suzuki-Miyaura coupling reaction were carried out by using this new monomer as the main chain unit of π−conjugated polymer for polymerization. Introduction of a long alkoxy chain into coumarin monomer unit significantly improved the solubility of thus obtained polymers. The absorption and emission spectra of polymers showed red-shift compared to those of monomer, indicating the expansion of the π−conjugated system in the polymer main chain. Especially the polymers synthesized via Sonogashira coupling formed excimer in film state. The polymers showed acid-base responsibility with the addition of KOHaq and HClaq.

Exceptional Alignment in a Donor–Acceptor Conjugated Polymer via a Previously Unobserved Liquid Crystal Mesophase

AbstractOrienting polymer semiconductors is desirable to optimize device characteristics, provide insight into microstructure, and magnify subtle phase behavior. Here, a combination of uniaxial strain and subsequent heating of the donor–acceptor (DA) polymer PBnDT‐FTAZ is discovered to lead to exceptional optical dichroic ratios of up to 38 (and close to 50 near the polymer's absorption edge). This alignment is achieved due to the existence of a previously undetected thermotropic liquid crystal (LC) mesophase. The LC transition, not discernable through calorimetry, is uncovered through a combination of in situ UV–vis spectroscopy, X‐ray scattering, and dynamic mechanical analysis (DMA). Comparing PBnDT‐FTAZ to the non‐fluorinated PBnDT‐HTAZ and the homo polymer PBnDT, all of which show similar thermal transitions, reveals that exceptional alignment is only found in PBnDT‐FTAZ. This is attributed to the PBnDT‐FTAZ film having two distinct liquid crystal populations, and the polymer templating to a highly aligned, high‐clearing temperature population when heated. The DMA thermal relaxation behavior observed here is also seen in other DA conjugated polymers suggesting that such thermotropic LC mesophases may be common in these materials. These findings demonstrate a polymer semiconductor with remarkable alignment and uncover phase behavior with broad implications for process‐structure‐property relationships in polymer semiconductors.

Electromagnetic wave absorption of polymer derived ceramic composites tuned by multi-component oxide solid solution

Polymer-derived ceramics (PDCs) are important ceramics for high temperature electromagnetic wave (EMW) absorption because of their tunable conductivity with the pyrolysis temperature. However, it is usually difficult to tune the dielectric properties of the PDCs by only controlling the content of absorption phase in the material system for the purpose of acquiring a wide EMW absorption band. In this work, we illustrate that the PDCs with wide-band high temperature absorption can be obtained through the synergistical tuning by multi-component oxide solid solution (MOS), nano ZrB2 and the metamaterial structure design. The PDCs were prepared by co-pyrolyzing the SiOC precursor, nano ZrB2 and MOS. The MOS helps to tune the permittivity of the PDCs without decreasing the conduction loss of the composites. The effective absorption band (lower than −10dB) of the metamaterial structure made by the prepared ceramic composites exceeds 12 GHz at the frequency range of 2–18 GHz from room temperature (RT) to 1000 °C, revealing a stable high temperature EMW absorption. The metamaterial structure shows good absorption in low frequency range at high temperatures, almost covering the entire S band from RT to 700 °C. The average EM absorption of the ceramic composites is lower than −15dB in the range of 2–18 GHz from RT to 1000 °C. The lowest reflection loss (RL) of the metamaterial is −45dB at 1000 °C. This study successfully address the challenge of simultaneously keeping impedance matching and retaining the strong attenuation of ceramic composites, greatly widening the high temperature EMW absorption band of PDC composites.

In Vitro Study of the Surface Roughness, Hardness, and Absorption of an Injection-Molded Denture Base Polymer, Manufactured under Insufficient Mold Solidification

The current study sought to investigate the changes in surface hardness, roughness, and moisture absorption of the Vertex ThermoSens polymer (Vertex Dental, 3D Systems, The Netherlands) following immersion in artificial saliva for various periods (7, 14, and 28 days). A total of 60 rectangular specimens with dimensions of 20 mm in length, 20 mm in width, and 3 mm in thickness were made. Due to insufficient mold solidification, these specimens were made utilizing the injection molding process. A Mitutoyo Surftest 4 roughness meter (Mitutoyo, Aurora, IL, USA) was used to measure the surface roughness of the test materials. The ThermoSens polymer hardness was assessed using the Shor method and D—HSD scale, while absorption was measured with a Sartorius analytical balance. Results indicated the highest mean hardness after 28 days (M = 77.6) (Surface 1) and the lowest for the control group (M = 59) (Surface 2). The maximum surface roughness occurred in direction 2.2 pre-immersion (Ra = 2.88 μm) and 7 days post-removal (Ra = 2.95 μm). The control group exhibited the lowest absorption (Wsp = 1.524 mg/mm3), with the highest mean values over 28 days (Wsp = 1.541 mg/mm3). The elevated flask and plaster temperature slowed polymer solidification, resulting in longer macromolecules and improved mechanical properties and surface features.

Excitonic one-photon absorption of one- and two-dimensional C60 polymers: Insights from many-body first-principles calculations

By solving the many-body Bethe–Salpeter equation, we explored the excitonic one-photon absorption of one- and two-dimensional C60 polymers. We studied seven polymeric structures including C60-chain, two structures with quasi-tetragonal phases (qTP1 and qTP2), and four structures with quasi-hexagonal phases (qHP1, ML-qHP2, BL-qHP2, and bulk-qHP2). The one-photon excitonic transitions were analyzed in detail relative to the independent particle transitions. Significant red-shifts (0.4 and 0.2 eV for ML-qHP2 and BL-qHP2, respectively) were observed in the excitonic one-photon absorption of low-dimensional polymers compared to bulk polymers. The red-shift can be related to the dimensional and interlayer dependences of screening effect which lead to different binding energies (0.61, 0.44, and 0.27 eV for ML-qHP2, BL-qHP2, and bulk-qHP2, respectively). For two qHPs (i.e., qHP1 and ML-qHP2), different connection modes between C60 molecules lead to different types (direct and indirect for qHP1 and ML-qHP2, respectively) of electronic band gap, and they also have different spectral profiles due to different hole and electron densities of excitons. Finally, the C60-chain formed by [2 + 2] cycloadditions has a direct band gap of 2.09 eV which is desirable for applications in photoelectric devices based on the solar spectrum.

Simulation of exciton spectra in disordered supramolecular polymers: exciton localization in cisoid indolenine squaraine hexamers.

In order to understand the effects of disorder and defects in oligomers and polymers on the localization of excitons, we investigated the spectral properties of the squaraine B hexamer using long range corrected tight-binding TDDFT (lc-TDDFTB) and Frenkel-exciton model based calculations. Employing classical molecular dynamics, the cisoid indolenine squaraine hexamers helix was propagated in DCM and acetone to obtain ensembles of realistic structures, which naturally exhibit considerable disorder. The trajectories together with several model squaraine systems were studied to show the profound effects of disorder in the superstructure and disorder of the local monomer geometry on optical properties like absorption and exciton localization. We further compared lc-TDDFTB and exciton theory derived spectral data to related experimental data on absorption, exciton transfer and localization in squaraine polymers and oligomers.

Radiative transfer model and validation for infrared management optical properties of porous polymer materials incorporating impacts of micro-voids

In order to characterize the infrared (IR) radiation absorption and/or emission performances of functional porous polymers which claim to have healthcare functions due to IR excitation and emission by processing technologies, a radiative transfer model was constructed based on the principle of IR radiation, the Beer–Lambert law, the Fresnel’s formula and Planck’s law. The theoretical analysis was conducted for the IR management optical properties of the porous sheet polymer materials, including IR reflection, transmission, absorption and emission behaviours during the dynamic process of IR radiation. A modeling method for characterization and revealing of IR management optical properties and optical and thermal transfer behaviours of the reflection and transmission was then investigated from the structural parameters and the temperature rise characteristics of the porous sheet polymer materials during the dynamic IR radiation process. The model was validated by comparing the predicted values from the radiative transfer model with the measured values from the test results of the validation experiments of eight typical porous sheet polymers in an experimental setup. The model was modified by consideration of the influences of two types of micro-voids defects represented by the porosity of micro structure and the thickness compression ratio. The micro-voids defects factors were added to the structural parameters, and therefore the model was improved and the maximum prediction errors of the transmission and reflection surfaces were mostly less than 10%. The radiative transfer model provides the theoretical fundamentals for the evaluation and guidance of IR management optical performances for new products design, development, fabrication and processing in industrial application of functional porous polymers.

Insight into alkaline stability of N-heteroatom on N-dimethylpiperidinium based anion exchange membranes (AEMs) for alkaline water electrolysis

Alkaline stability is the main obstacle for anion exchange membranes (AEMs) for alkaline electrolysers. In order to research the effect of N-heteroatom polymers on the alkaline stability of N-dimethylpiperidinium (DMP) based AEMs, in this work, nine kinds of blend membranes were prepared by blending poly (oxindole biphenylene) (POBP), poly (N-methylisatin biphenylene) (mPOBP) and poly (biphenyl 4-imidazolecarboxaldehyde) (PB4Im) with poly (aryl piperidine) polymers (PTP-85) at the ratio of 1:19, 1:9, and 1:4, respectively. Moreover, in the preliminary investigation of alkaline stability, we broke the limitation of the immiscibility of the blend membranes and performed a comparative investigation by the 1H NMR. Surprisingly, the obtained blend membranes showed a much higher degree of degradation than PTP-85 in terms of ex-situ alkaline stability. The alkali absorption of different N-heteroatom polymers in different concentrations of NaOH at 55 °C and 80 °C showed that the alkaline stability of blend membranes was lower with the increase of alkali absorption. The in-situ stability test also demonstrated that the performance of blend AEMs decreased significantly after in-situ durability test under the galvanostatic mode. These results showed that blending with N-heteroatom polymers could negatively affect the alkaline stability of DMP-based AEMs, providing insight into the relationship between N-heteroatom and stability of DMP-based AEMs.

Research of Water Absorption and Release Mechanism of Superabsorbent Polymer in Cement Paste.

The water absorption and release properties of superabsorbent polymers' (SAP) internal curing agent are affected by many factors, such as solution properties, the ambient temperature and humidity and the particle size of SAP, which determine the curing effect and the durability of cement concrete structures directly. In this paper, the variation rule of the water absorbing capacity of SAP in simulated cement paste under different solutions and environmental conditions was studied. Based on microscopic image technology, the dynamic swelling behavior of the SAP particles was explored. The water release performance of SAP in cement paste was analyzed by both the tracer method and the negative pressure method. The results show that the water absorption of SAP in cement paste varied from 27 to 33 times. The ionic valence had a significant effect on the water absorption capacity of SAP, which suggests that the larger the ionic radius, the lower the absorption of SAP. The higher the temperature of the solution, the greater the water absorption rate of SAP. While the SAP particle size was less than 40-80 mesh, a slight 'agglomeration effect' was prone to occur, but the absorption state of SAP was more stable. Based on the swelling kinetic equation of SAP and the time-dependent swelling morphology of SAP in cement paste, a swelling kinetic model was established. The water release performance of SAP was less affected by the capillary negative pressures, and it would not release the water prematurely during the plastic stage, which was conducive to the continuous internal curing process of hardened paste in the later stage.

A microfluidic-based In-situ investigation of swelling dynamics of superabsorbent polymer microparticles

This paper presents a novel microfluidic-based technique for in-situ time-lapse investigation of the dynamic water absorption (or swelling) of individual superabsorbent polymer (SAP) microparticles (MPs). Most prior studies were restricted to using gravimetric techniques to investigate the equilibrium state of the swelled SAP macroparticles, without considering their swelling dynamics. Time-lapse investigation of the swelling rate is essential for optimizing SAP-MPs' performance to meet the needs of different applications. Moreover, since swelling occurs through the surface of SAP particles, we hypothesize that decreasing their size to microscale (i.e., SAP-MPs) could potentially improve their performance due to the increased surface area-to-volume ratio. In this context, the proposed microfluidic device enabled hydrodynamic trapping of an array of individual SAP-MPs and in-situ investigation of their swelling behaviour under a microscope. The SAP-MPs were initially suspended in ethanol and loaded into the microfluidic device. Once they were trapped, the fluid medium was switched to water to trigger their swelling. Acrylic acid (AA)/acrylamide (Aam)-based SAP-MPs in size range of 250–300 µm were investigated to characterize the device's performance. The SAP-MPs' average trapping time and yield in the device were 9.56 s per SAP-MP and 92%, respectively, at an ethanol loading flow rate of 0.15 mL/min. A minimum water flow rate of 5 mL/min was required to achieve an average ethanol-to-water transition time of 10 s. This was needed to suppress the effect of the solution exchange on the swelling behavior of the SAP-MPs. The equilibrium volumetric swelling ratio (VSReq), swelling rate (SR), and initial SR of AA-Aam-based SAP-MPs were determined to be 5.59 ± 0.13 (m3/m3), 0.039 ± 0.002 (m3/m3.s), and 0.068 ± 0.010 (m3/m3.s), respectively. A significant effect of the neutralization degree (ND) on the swelling behavior of AA-Aam-based SAP-MPs was also observed. At 90% ND, the maximum VSReq of 79.45 ± 2.49 m3/m3 and SR of 1.11 ± 0.047 m3/m3·s were achieved. This microfluidic platform could be used to conduct parametric study and real-time characterization of various SAP-MPs in biological, chemical, medical, and agricultural applications.

물 흡수에 따른 다양한 고분자 재료의 기계적/트라이볼로지적 물성 연구

The physical, chemical and mechanical properties of polymer materials used in water environment for a long time will change due to their water absorption characteristics, which will affect their tribological properties. This work studied the changes of physicochemical, mechanical, and tribological properties for five kinds of polymer materials (polyethylene, polyformaldehyde,polyamide, polytetrafluoroethylene, and poly-ether-etherketone) before and after water absorption. The mechanism of water absorption for polymer materials was revealed by molecular dynamics simulation. The results show that the higher the water absorption of polymer, the larger the swelling volume, the more the surface hardness and compressive strength decrease, and the toughness and friction coefficient of the material increase obviously. The water absorption status of polymer materials is closely related to the polarity of molecular chain. Water molecules are easy to form hydrogen bonds with polymer molecular chains of high polarity, which is the main factor of water absorption.