Polyester Layer Research Articles

The Efficiency of Polyester-Polysulfone Membranes, Coated with Crosslinked PVA Layers, in the Water Desalination by Pervaporation.

Composite polymer membranes were obtained using the so-called dry phase inversion and were used for desalination of diluted saline water solutions by pervaporation (PV) method. The tests used a two-layer backing, porous, ultrafiltration commercial membrane (PS20), which consisted of a supporting polyester layer and an active polysulfone layer. The active layer of PV membranes was obtained in an aqueous environment, in the presence of a surfactant, by cross-linking a 5 wt.% aqueous solution of polyvinyl alcohol (PVA)-using various amounts of cross-linking substances: 50 wt.% aqueous solutions of glutaraldehyde (GA) or citric acid (CA) or a 40 wt.% aqueous solution of glyoxal. An ethylene glycol oligomer (PEG 200) was also used to prepare active layers on PV membranes. Witch its help a chemically cross-linked hydrogel with PVA and cross-linking reagents (CA or GA) was formed and used as an active layer. The manufactured PV membranes (PVA/PSf/PES) were used in the desalination of water with a salinity of 35‱, which corresponds to the average salinity of oceans. The pervaporation method was used to examine the efficiency (productivity and selectivity) of the desalination process. The PV was carried at a temperature of 60 °C and a feed flow rate of 60 dm3/h while the membrane area was 0.005 m2. The following characteristic parameters of the membranes were determined: thickness, hydrophilicity (based on contact angle measurements), density, degree of swelling and cross-linking density and compared with the analogous properties of the initial PS20 backing membrane. The physical microstructure of the cross-section of the membranes was analyzed using scanning electron microscopy (SEM) method.

Performance and Life Cycle Assessment of Composites Reinforced with Natural Fibers and End-of-Life Textiles

The growing need for materials that are eco-friendly and sustainable in the industrial sector has shifted focus from synthetic fossil to natural fibers, alongside the utilization of recycled polymer textiles. This research introduces a novel method for using end-of-life textiles, such as polyester and polyamide fabrics, in the production of composite materials, aiming to lessen textile waste and enhance material longevity. The mechanical attributes of flax fabric (FF), flax–recycled polyamide fabric (F/RPA), and flax–recycled polyester fabric (F/RPES) composite laminates are assessed through tensile, flexural, interlaminar shear, and Charpy impact tests. The study revealed that the addition of end-of-life synthetic fibers improves tensile strength, while the trend in modulus values suggests that flax provides a high degree of stiffness to the composites, which is moderated by the addition of synthetic fibers. This effect is consistent across both tensile and flexural testing, although the impact on stiffness is more significant in bending. The inclusion of polyester fibers in the composite laminate resulted in significant enhancements, with an 11.1% increase in interlaminar shear maximum force, a 17.4% improvement in interlaminar shear strength, and a 67.1% rise in un-notch impact energy, compared to composites made with only flax fiber (FF). The microscopic examination uncovered the internal structure and demonstrated a clear, strong bond between the polyester and polyamide fiber layers with the flax fibers. Additionally, the life cycle assessment revealed that the F/RPES composite had less environmental impact than FF and F/RPA in all 18 categories analyzed. This indicates that the environmental footprint of producing F/RPES is smaller than that of both FF and F/RPA.

Fabrication of anti-fouling polyester nanofiltration membrane for dye desalination

Polyester nanofiltration membranes with a loose selective layer are highly promising for separating dyes and salts. In this study, three anti-fouling polyester nanofiltration membranes were prepared by interfacial polymerization of xylitol (E967), xylitol/β-cyclodextrin (E967/β-CD), and xylitol/sodium alginate (E967/SA) with trimesoyl chloride on a polyethersulfone (PES) substrate. The chemical structure, morphology, pore size, hydrophilicity and zeta potential of three polyester membranes were characterized. The preparation conditions, separation performance for dyes and salts, and anti-fouling properties were studied. The results indicated that the addition of β-CD or SA inhibited the esterification reaction, resulting in a thin and loose polyester layer. The polyester layer thicknesses of the PES/E967/β-CD and PES/E967/SA membranes were 92 nm and 79 nm, respectively. In addition, the hydrophilicity and electronegativity of the polyester layer were enhanced. Three polyester membranes all showed a rejection of >99.5 % for Congo red. The permeance of the PES/E967/β-CD membrane was the highest (18.3 L·m−2·h−1·bar−1), whereas the NaCl rejection of the PES/E967/SA membrane was the lowest (9.1 %). Compared with the PES/E967 membrane, the fouled PES/E967/β-CD and PES/E967/SA membranes had longer wash cycles, suggesting an advantage in dye/salt separation.

The amount of improvement and therapeutic effect of sports health by increasing the viscosity of peach juice through reverse osmosis and polymer membrane

In this study, the performance of polyamide membranes embedded with synthesized silica nanoparticles was evaluated for pomegranate juice concentration using the reverse osmosis (RO) process. The research aims to explore the potential therapeutic benefits and measurable improvements in sports health achieved by employing RO and a polymer membrane to enhance the viscosity of peach juice. The membranes utilized in this study feature a multi-layer structure comprising a non-woven polyester layer for strength, a sulfone polyether polymer sheet, and a polyamide layer synthesized through the copolymerization of m-phenylenediamine and benzene tricarboxylic chloride. To enhance the membrane properties, silica nanoparticles were incorporated into the second layer. The experiment was designed using Design Expert software, considering three parameters: weight percentage of polyether sulfone at three levels (12%, 16%, and 20%), weight percentage of silica nanoparticles at three levels (0%, 0.1%, and 0.2%), and the process pressure at three levels (20, 25, and 30 bar). The optimal membrane configuration obtained from this experimental design consisted of a sulfone polyether polymer content of 16%, silica nanoparticles concentration of 2%, and a working pressure of 23.24 bar. Furthermore, the findings of this study suggest that the application of polymer materials and nanoparticles for membrane modification holds potential benefits for the juice industry in the future. However, it is essential to consider the wide range of factors that can influence the properties of nanocomposite membranes.

Sustainable β- and γ-cyclodextrins for development of highly permeable thin film composite nanofiltration membranes

The use of macromolecules, such as cyclodextrins (CDs), given their porosity and compatibility with organic materials, are very attractive for the progress of polymeric membranes in nanofiltration (NF) of aqueous dye solutions. Two types of membranes were fabricated. Firstly, β- and γ-CDs were incorporated to polyamide (PA) thin film composite (TFC) membranes. These membranes, named CD/MPD-TMC, were prepared by conventional interfacial polymerization —i.e., an aqueous solution of m-phenylenediamine (MPD) followed by a solution of trimesoyl chloride (TMC) in hexane— by replacing a certain amount of the MPD monomer with varying proportions of CDs. Secondly, two-step double-IP (TD-IP) membranes were fabricated as follows: CDs were deposited atop the polymer support, followed by addition of TMC —forming a polyester (PE) layer—, and subsequently the membrane surface was modified with MPD molecules. In both CD/MPD-TMC and TD-IP membranes, the presence of CDs improved the membrane performance, the latter configuration leading to much higher water permeances. The TD-IP membrane using β-CD achieved the highest water permeance of 10 L m−2 h−1·bar−1 (LMH bar−1) and a rejection of acridine orange dye (265 Da) greater than 98 %. This represents a 6-fold increase in water permeance compared to bare PA (1.6 LMH bar−1). The enhanced water transport was mainly attributed to the more hydrophilic nature of the membranes and the presence of a PE layer with a porous structure and high pore connectivity. High dye rejection resulted from electrostatic and Donnan repulsions due to surface modification with MPD molecules.

Recycling of HIPS and multilayer films with SEBS-based additives

With the evolution of new polymers and an increase in their scope of applications, the use of natural resources such as petroleum products for polymer production has seen a drastic increase in the past few years. With production rates higher than ever and rapid, unsafe disposal of used polymers has taken a toll on the environment and other species through pollution. Even though there are alternative solutions, including bioplastics manufactured from greener sources and biodegradable plastics that can disintegrate in a shorter time period, these alternatives are currently in their early stages and hence expensive. It is also more challenging for them to meet the high demands in terms of both quantity and properties. The next nearest alternative, recycling, is the best available solution to avoid plastic waste entering landfills and to reduce raw material demands. This study aims to determine the effectiveness of a newly introduced styrene–ethylene–butadiene block copolymer (SEBS)-based property enhancer (WinMod 300) with disposed high-impact polystyrene (HIPS) and a maleic anhydride-grafted SEBS compatibilizer (WinMod 110) with disposed multilayer films (low-density polyethylene and polyester layers). Recycled compounds were tested for necessary and significant mechanical properties and subjected to material characterization, and the results are presented in this paper.

Design of a novel TA-MoS2 nanosheets interlayer-based loose nanofiltration membrane for enhanced dye/salt separation

From the view of sustainable development, the loose nanofiltration (LNF) membrane with high permeability and excellent separation of dye/salt mixture becomes more attractive for dye-containing wastewater. However, the previous LNF membranes inevitably suffered from the permeability-selectivity trade-off due to the inherent nature of polymer-based selective layer. This study reported a tannic acid (TA)-MoS2 nanosheets (NSs) interlayered nanocomposite polyester (PE) LNF membrane (iLNF-3) that exhibited a remarkably enhanced water permeance of 55.8 LMH·bar−1 compared to the control LNF membrane of 27.3 LMH·bar−1, and a higher separation selectivity of dye/salt (rejection rate: 99.6 % for congo red, 98.0 % for methyl blue, 5.6 % for Na2SO4, respectively). Furthermore, the iLNF-3 showed high ionic interference resistance, long-term stability, and superior antifouling performance. The enhanced permeance and dye/salt separation were mainly attributed to the introduction of a high-permeability TA-MoS2 NSs interlayer. In particular, the permeability was improved due to the “gutter” effect and nanochannels and the formed thinner PE selective layer caused by TA-MoS2 NSs interlayer. Notably, the selectivity was enhanced owing to the looser porous structure of PE layer resulting from the slow diffusion rate of aqueous monomer. This study can provide a foundational framework for the development of iLNF membranes for treating dye containing wastewater.

Development and a feasibility study using Gafchromic XRQA2 film as a novel passive radon measurement technique

In the present paper, a novel passive-type radon measurement technique based on Gafchromic XRQA2 film was developed. A Gafchromic XRQA2 film was modified by peeling off a polyester layer to enhance the film sensitivity to alpha particles, which were mainly emitted from radon and its progeny, and the response of the modified Gafchromic XRQA2 film to alpha particles was investigated. The results indicated that, with the increase in time-integrated alpha activity, the darkness of the exposed modified Gafchromic film increased, and only a small alpha energy dependence with less than 2% relative difference in the film response was observed. Next, the modified Gafchromic XRQA2 film was deployed with a RADUET container for radon measurement to evaluate application feasibility, and the radon response of the modified Gafchromic XRQA2 film was compared with the traditional one of a RADUET with CR-39 detector. The radon calibration was investigated using the radon exposure chamber. The obtained calibration functions showed that the net optical density of modified Gafchromic XRQA2 film was directly proportional to the accumulated radon concentration over the exposure period. From the calibration, the minimum and maximum detectable radon concentrations for a three-month measurement period were estimated to be about 390 Bq m−3 and 15,000 Bq m−3, respectively. Moreover, this technique enables to minimize the effect of thoron interference by the RADUET container design. These results suggest that this technique can be used for measuring radon, particularly in areas with potentially high radon concentrations, for example, underground mines and caves.

High permeance nanofiltration membrane for harsh organic solvent based on spiral-ring polyesters

Currently, many polymeric membranes are poorly tolerated in harsh (strong polar aprotic) solvents like dimethylformamide (DMF) and N-methylpyrrolidone (NMP) and are not applicable to organic solvent nanofiltration (OSN). In this study, we combined the oxidized poly (arylene sulfide sulfone) (OPASS) supports with excellent organic solvent resistance and the spiral-ring polyester interfacial polymerization (IP) layer together to fabricate ultra-resistant and high permeance membranes for OSN. The tetramethyl-1,1′-spirobisindane-6,6′diol (SBI), a contorted diphenol monomer with a spiral-ring structure, was preferentially selected from six types of polyphenols based on molecular simulations and experimental results. It was conducted to react with trimesoyl chloride (TMC) via interfacial polymerization to yield a polyester separation layer of thin film composites (TFC). Investigating the different alkali ratios and types revealed that the alkali added in the aqueous phase to improve the solubility of the SBI could cause hydrolysis of the polyester layer generated by IP, which led to increased membrane permeance and reduced rejection, and the more alkali and the stronger the alkali used, the more severe the hydrolysis. Besides, DMF activation treatment to the TFC membrane improved the ethanol permeance by at least four times while maintaining high congo red rejection. As a result, combining the effects of alkali and DMF activation, the representative TFC membranes fabricated in our work exhibited excellent permeance of 21.5±1.3, 9.0±1.1 L m−2 h−1 bar−1 for DMF and NMP, respectively, and high rejection rates (≥ 93%) for congo red (Mw 696.7 Da), higher than the earlier reports. This research presents a new and straightforward approach to developing TFC membranes with high-efficiency filtration capabilities, suitable for harsh organic solvent separation applications.

Development and Characterization of Hybrid, Temperature Sensing and Heating Yarns with Color Change.

A person's body temperature is an important indicator of their health status. A deviation of that temperature by just 2 °C already has or can lead to serious consequences, such as fever or hypothermia. Hence, the development of a temperature-sensing and heatable yarn is an important step toward enabling and improving the monitoring and regulation of a person's body temperature. This technology offers benefits to several industries, such as health care and sports. This paper focuses on the characterization and development of a hybrid yarn, which can measure and visualize temperature changes through a thermoresistive and thermochromic effect. Moreover, the yarn is able to serve as a flexible heating element by connecting to a power source. The structure of the yarn is designed in three layers. Each layer and component ensures the functionality and flexibility of the yarn and additional compatibility with further processing steps. A flexible stainless steel core was used as the heat-sensitive and heat-conducting material. The layer of polyester wrapped around the stainless steel yarn improves the wearing comfort and serves as substrate material for the thermochromic coating. The resulting hybrid yarn has a reproducible sensory function and changes its resistance by 0.15 Ω between 20 and 60 °C for a length of 30 cm. In addition, the yarn has a uniform and reproducible heating power, so that temperature steps can be achieved at a defined length by selecting certain voltages. The thermochromic color change is clearly visible between 28 and 29 °C. Due to its textile structure, the hybrid sensory and actuating yarn can easily be incorporated into a woven fabric or into a textile by means of joining technology sewing.

Nanocrystalline Silver Layer of Knitted Polyester Outperforms Other Silver-Containing Wound Dressings in an In Vitro Wound Model.

Background Silver possesses cytotoxic properties against many microorganisms and is regularly used in wound care. Current evidence supporting the use of one type of silver-containing wound dressing (SCWD) is insufficient. Materials and methods To examine the ability of selected SCWDs to inhibit the growth of two strains of bacteria (Escherichiacoli and Staphylococcus aureus) commonly found in wounds, an in vitro wound model was used.Bacteria were applied to the surface of nutrient agar, and a piece of each SCWD was applied to the bacteria.The plates were incubated at 37°C overnight. The zone of inhibition (ZI) around each SCWD was measured in cm2. Results The mean ZI for Acticoat Flex-3 on E. coli was 1.59 ± 0.15 cm2, which was significantly greater than that observed for Aquacel Ag (p<0.001), Mepilex Ag (p<0.0001), Mepitel Ag (p<0.001), Optifoam (p<0.0001), and Tegaderm Alginate Ag (p<0.01), but statistically indistinguishable from Maxorb II Ag. The mean ZI on S. aureus was 1.21 ± 0.16 cm2, which was greater than Aquacel Ag (p<0.05), Mepilex (p<0.0001), Optifoam (p<0.0001), and Tegaderm Alginate Ag (p<0.05), but statistically indistinguishable from Maxorb II Ag or Mepitel Ag. Conclusion Of the SCWDs tested, Acticoat Flex-3 demonstrated the most robust antimicrobial effect.Herein, we show that Acticoat Flex-3 may provide the most wound protection against bacterial infection. In conclusion, these data provide clinicians with additional independent evidence to inform their clinical practice on the use of specific wound dressings.

Carbonate modified polyester nanofiltration membrane: Separation performance and mechanism investigation

The development of loose nanofiltration (LNF) membranes with high water flux and excellent separation performance is of great significance for wastewater treatment and resource recovery. As a green polyphenol with high molecular weight, tannic acid (TA) is an attractive aqueous monomer to prepare LNF membranes via interfacial polymerization (IP) with trimesoyl chloride (TMC). To the best of our knowledge, this work first reports a facile and delicate method to regulate reaction sites of the aqueous monomer by oxidizing a certain proportion of hydroxyl groups under weak alkaline condition caused by carbonate to tailor the morphology of polyester layer. The resulted nanobubbles generated by the reaction of carbonate with H+ produced during the IP reaction (which also promoted the IP process) rendered polyester layer nanovoids structure. Compared with the pristine membrane, the tailored morphology of active layer decreased 93.24% membrane resistance and significantly improved water flux up to 13.55 times, while maintained effective dye/salt separation. Furthermore, the polyester NF membrane possessed high electronegativity and abundant oxygen-containing functional groups, which could effectively remove heavy metal ions Pb2+, Cu2+ and radionuclide uranium (U(VI)) from water through Donnan effect and adsorption, with the rejection rates of above 95.39%, 94.71% and 99.35%, respectively. This work provides a noteworthy modification idea for the preparation of high-performance multifunctional LNF membranes derived from green polyphenols to deal with some challenges such as dye separation, heavy metal ions and radionuclide removal.

Influence of the incorporation of flexographic photopolymer plate residues on the mechanical properties of epoxy

A thermosetting epoxy polymer composed of diglycidyl ether of bisphenol A and triethylenetetramine (DGEBA/TETA) was modified by incorporating flexographic photopolymer plate residues (rubber microparticles). The photopolymer plate residues were processed in two ways: (a) by grinding and performing particle size classification (where the resulting samples were denoted PP) and (b) by polyester layer separation and grinding the elastomeric fraction by cryogenic grinding (where the resulting samples were denoted ER). Both residual particles were incorporated into the epoxy at concentrations of 2.5, 5 and 7.5 wt%. The main results indicate that PP was not efficient as a modifier of the epoxy system. A reduction in mechanical properties (maximum tensile strength and deformation) was observed in the samples produced with PP in different concentrations. But, when the ER is incorporated, an increase in tensile property and in the deformation capacity, as well as impact resistance was observed in samples produced with ER. Scanning electron microscopy analysis showed a greater presence of voids in formulations produced with PP, which corroborates the decrease in the tensile strength of these samples.

Mechanistic insight into developing a novel loose nanofiltration membrane for effective dye/salt separation by epigallocatechin gallate

Loose nanofiltration (LNF) membrane prepared by hydroxyl-based materials with excellent separation and antifouling properties has attracted great attention for treating textile wastewater. However, the construction and formation mechanism of the selective layer by using large polyphenol-based monomers was not well studied. Herein, a novel LNF membrane was fabricated by interfacial polymerization, in which a polyphenol named epigallocatechin gallate (EGCG) was employed as aqueous monomer to design the selective layer. The results illustrated that the formed polyester (PE) selective layer possessed a loose structure with smooth and hydrophilic surface. Notably, the EGCG with large molecular volume and polyphenol groups contributed to the larger molecular weight cut-off (MWCO) and hydrophilic PE layer with high permeability, whereas the small molecular trimesoyl chloride (TMC) accounted for the pore size reduction with low permeance. More importantly, the optimized EGCG-based LNF-4 membrane displayed a high water permeability of 41.7 LMH·bar−1, high rejection of dyes (98.5 % for Congo Red (CR), 93.4 % for Methyl Blue (MB), and 94.8 % for Evans Blue (EB), respectively) and low rejection of salt (7.4 % for NaCl). Besides, under 60 g/L salt content, a high retention of CR (93.0 %) and high permeation of NaCl (95.1 %) could be still maintained. Furthermore, the LNF-4 membrane had a superior fouling resistance towards CR and EB with flux recovery rate above 96.4 %. The excellent antibacterial property also made LNF-4 more competitive in practical applications. This work can provide a new strategy for fabrication of outstanding multifunctional LNF membranes by large molecular polyphenol monomers.

Fabrication of bio-fiber based Eichhornia crassipes/Al2O3 particles hybrid biocomposites and investigation of important properties

The need for environmentally friendly composite materials that meet the necessary criteria is growing. Making novel environmentally acceptable composites with hybrid Eichhornia crassipes (EGs)/Al2O3 particles is an option. This paper aims to investigate the thermal, tensile strength, and flexural strength properties of a polyester composite filled with hybrid EG/Al2O3 particles. The tensile strength, flexural strength, and morphology of EGs/Al2O3 hybrid composite will be investigated in this work. The hot pressed for 60 minutes at 170°C procedure was used to shape the hybrid composite. EGs/Al2O3 particles content was altered from 0:25 to 5:20, 10:15 to 15:10, 20:5, and 25:0 (vol.%). The results reveal that when the EGs content of the composite is in the range of 10–15% (vol.%), the tensile and bending strength of the composite increases. The EGI (15% EGs:10% Al2O3) and EGH (10% EGs:10% Al2O3) composites had the highest tensile and bending strengths, with 38.697 and 77.786 MPa, respectively. The boost in strength is thought to be due to Al2O3 acting as a cursor in the composite, preventing fracture progression. The scanning electron microscope (SEM) fracture morphology reveals a strong and tight interfacial connection between the EGs, Al2O3, and polyester layers. In addition, when the EGs grew, the composites’ thermal characteristics improved. According to the findings, the EGs/ Al2O3 particle hybrid composite can be used in automotive applications.

An experimental evaluation of polyamide membrane-silica nanoparticles for the concentration of pomegranate juice

Membrane processes are used in the food and nutrient industry in terms of their proper performance and selective separation. Using the membranes in fruit juice concentrating operations improves its quality via shelf-life increases. The advantage of reverse osmosis (RO) and membrane technology over other methods is its non-chemical reaction to fruit juice which increases the concentration of fruit juice. The membranes were made of three layers of non-woven polyester layer for the mechanical strength of the membrane, polyester sulfone polymer with polyamide consisting of polymerization of M-Phenylenediamine (MPD) and benzene tricarbonyl chloride. Trimethyl chloride (TMC) was used to modify the properties of the membrane in the second layer using silica nanoparticles. The feed was sugar-free pomegranate juice added by SUNICH Company with an initial Brix value of 14.9% and an input feed of 6.6% to the RO system. The DESIGN-EXPERT method for the design of experiments (DOE) by considering three parameters of weight percentage of polyester sulfone polymer (12, 16, and 20%), silica nanoparticles (0, 0.1, and 0.2 wt%), and operating pressure were used (20, 25, and 30 times). Under optimal conditions, 46.15% of the concentrated pomegranate juice were obtained by experiment and the amount of brix increased from 33.24% to 47.21%. Scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), and contact angle tests for membranes were used. In the analysis of contact angle by examining the degree of hydrophilicity and contact angle of water droplets, it was found that the presence of silica nanoparticles and polyamide layer caused more hydrophilicity of membranes. It can be concluded that the pressure parameter, together with the presence of nanoparticles and polymer percentages, contribute to the most successful procedure of concentrating pomegranate juice.

New Insights into the Mechanical Behavior of Thin-Film Composite Polymeric Membranes.

Limited predictions of thin-film composite (TFC) membranes' behavior and functional life exist due to the lack of accurate data on their mechanical behavior under different operational conditions. A comprehensive investigation of the mechanical behavior of TFC membranes addressing deformation and failure, temperature and strain rate sensitivity, and anisotropy is presented. Tensile tests were conducted on commercial membranes as well as on individual membrane layers prepared in our laboratories. The results reveal the overall mechanical strength of the membrane is provided by the polyester layer (bottom layer), while the rupture stress for the middle and top layers is at least 10 times smaller than that of the polyester layer. High anisotropic behavior was observed and is attributed to the nonwoven structure of the polyester layer. Rupture stress in the transverse (90°) direction was one-third of the rupture stress in the casting direction. Limited temperature and strain rate dependence was observed in the temperature range that exists during operation. Scanning electron microscopy images of the fractured surfaces were also analyzed and correlated with the mechanical behavior. The presented results provide new insights into the mechanical behavior of thin-film composite membranes and can be used to inform novel membrane designs and fabrication techniques.

PHSOR02 Presentation Time: 12:35 PM: Practical Considerations for Dosimetric Verification of Ru-106 Eye Plaque Vendor Certificate Using Radiochromic Film

<h3>Purpose</h3> To develop a practical and efficient method for the dosimetric verification of Ru-106 plaques using radiochromic film measurements. <h3>Materials and Methods</h3> A hemispherical Solid Water^TM phantom with two quadrants was constructed with 12 mm radius to fit with eye plaque models - CCA, CCB, CCD and COB (Eckert & Ziegler BEBIG GmbH, Berlin, Germany). Each Ru-106 plaque was placed on the convex surface of the phantom for the film irradiations. Two types of radiochromic Gafchromic^TM dosimetry films (Ashland Advanced Materials, Bridgewater, NJ, USA) were studied - HD-V2 film with 12 μm active layer on a 97 μm clear polyester substrate and EBT-XD film with 25 μm active layer sandwiched between two 125 μm thick clear polyester substrates. A hemispherical film cut was sandwiched between the two quadrants of the phantom. Irradiation time for each plaque was calculated based on the dose rate from the vendor source certificate per AAPM TG 221 protocol. For each plaque, at least three irradiations were completed with each film type. AAPM TG 55 recommendations were used for film handling and scanning. Film dose measurements were analyzed at clinically relevant depth of 2 mm - 5 mm. For each film type, an optical density to dose calibration curve was obtained using a NIST calibrated Sr-90 source and a NIST-traceable 6 MV clinical linac beam. Measured film dose obtained using the calibration curve was corrected with MCNP derived Solid Water^TM to water dose conversion factors. Measured film absolute dose to water was compared with predicted dose to water value from the vendor source certificate for each eye plaque. Type A and B uncertainty components were reported. <h3>Results</h3> Using 6 MV calibration for HD-V2 film, the average percentage dose difference between film-measured vs. calculated dose per AAPM TG 221 from the vendor certificate at depth of 2 mm (6MV-Cal_HD-V2_DD%) for CCA, CCB, COB and CCD plaques were -9.2%, -6.3%, 0.9% and -7.7% respectfully. Similarly, Sr-90-Cal_HD-V2_DD% were -11.1%, -2.4%, 0.1% and -6.7% respectively. For EBT-XD, 2.5 mm measurements were taken instead of 2 mm, because of artifacts from the film cutting technique at shallower depth. Hence at 2.5 mm, 6MV-Cal_EBT-XD_DD% were -10.2%, -7.2%, -7.4% and -10.1% respectively; and Sr-90-Cal_EBT-XD_DD% were -5.5%, -3.0%, -3.1% and -6.1% respectively. All the DD% were within the uncertainty of the film measurements performed (13% at 2 mm - 5 mm depth, k = 2 with Sr-90 film calibration) and reported by the vendor (11% at 2 mm depth, k = 2). Results from the 6 MV vs. Sr-90 calibration curve were within 2% for HD-V2 film and within 5% for EBT-XD film. The average DD% between 2 mm-5 mm depths were within 15% for all plaques for both film types, using either 6 MV or Sr-90 calibration methods. DD% was smaller at shallow depths and increased slightly and gradually at the deeper depths. EBT-XD film was more prone to film damage due to polyester layer separation and provided more heterogenous DD% results for 2.5 mm-5 mm depths. EBT-XD film also had more variance between the two film calibration methods. <h3>Conclusions</h3> We have provided a simple and efficient method for dosimetric verification of Ru-106 eye plaque vendor certificate with radiochromic film measurements. Based on our experience, the HD-V2 film calibrated with 6 MV clinical linac beam provides the most practical solution for dosimetric verification of the data provided in the Ru-106 eye plaque vendor certificate.

Study of moisture management properties of bamboo, wool and cotton trilayer knitted fabrics

Moisture management is a critical feature of any sportswear, as it improves the fabric's comfort level. Comfort differs from person to person depending upon the perception of the wearer. Comfort is the relation between a psychological and physiological behavior of the wearer. The moisture transmission of the fabric is the key determinant of thermophysiological comfort. The moisture management features of trilayer knitted fabrics constructed of a range of yarns on the inner and outer sides, including micro denier filament polyester, Monofilament, wool, bamboo, and cotton, are examined in this article. The sample B/MDPF/C, which included an inner layer of bamboo, a middle layer of Micro denier Filament polyester, and an outer layer of cotton shows appreciable moisture management property, providing an excellent comfort nature due to its appreciable property required for a moisture management fabric.

In-situ polymerization of different molecular weight polyethylene glycol and maleic acid onto carbon fiber for reinforcing polyamide 66

ABSTRACT The interfacial adhesion character highly depends on the molecular interactions on the interface, including bond combination and molecular entanglement, and mobility for sharing load. In situ polymerization of different molecular weight polyethylene glycol (PEG) and maleic acid (MA) is used to form a hyperbranched polyester (HBPE) layer on an electrochemically oxidized carbon fiber (OCF) surface. It is found that more terminal hydroxyl groups are formed under the reaction at 280°C than that at other temperature. The branch extent and molecule chain length on the HBPE sizing reach balance by choice of 2000 molecular weight PEG monomer. HBPE as a film has uniform coverage on the OCF surface. The interlaminar shear strength of polyamide 66 composite reinforced with the sized OCF by in situ polymerization of 2000 molecular weight PEG and MA at 280°C is the optimal, which is enhanced to 90.5 MPa by 169% compared to unoxidized fiber and by 70% compared to OCF. The significant interfacial property improvement is attributed to the abundant terminal hydroxyl groups and appropriate chain length of the formed HBPE sizing, which enhanced optimally the interaction of fiber/sizing and sizing/matrix by balancing the contribution of molecular entanglement, deformation and covalent interconnection to interface.