Poly Trimethylene Terephthalate Research Articles

Temperature Compensation of Fiber Bragg Grating Sensors in Smart Strand.

Compared to other types of sensors, fiber optic sensors have improved accuracy and durability. Recently, the Smart Strand was developed to maximize the advantages of fiber optic sensors for measuring the cable forces in prestressed concrete structures or cable-supported bridges. The Smart Strand has fiber Bragg gratings (FBGs) embedded in a core wire of the seven-wire strand. Similar to other sensors, the strain measured at an FBG is affected by temperature; therefore, the temperature effect that is not related to the mechanical strain should be compensated for or corrected in the long-term measurement subjected to temperature variation. However, a temperature compensation procedure for the FBG has yet to be established, and relevant studies have used different formulas for the compensation. Moreover, when the FBG sensors are packaged with a certain material—such as fiber reinforced polymer—for protection, it is important to consider the interaction between the FBG, packaging material, and host material during thermal behavior. Therefore, this study proposed a reasonable procedure for temperature compensation for the FBG sensors embedded in packaging material and host material. In particular, the thermal sensitivity of the Smart Strand was intensively investigated. The proposed theoretical formulas were validated through comparison with data obtained from various specimens in a temperature-controlled chamber. Finally, the procedure was applied to correct the data measured using the Smart Strands in a 20-m-long full-scale specimen for about a year, thus resulting in a realistic trend of the long-term prestressing force.

In Vitro One-Pot 3-Hydroxypropanal Production from Cheap C1 and C2 Compounds.

One- or two-carbon (C1 or C2) compounds have been considered attractive substrates because they are inexpensive and abundant. Methanol and ethanol are representative C1 and C2 compounds, which can be used as bio-renewable platform feedstocks for the biotechnological production of value-added natural chemicals. Methanol-derived formaldehyde and ethanol-derived acetaldehyde can be converted to 3-hydroxypropanal (3-HPA) via aldol condensation. 3-HPA is used in food preservation and as a precursor for 3-hydroxypropionic acid and 1,3-propanediol that are starting materials for manufacturing biocompatible plastic and polytrimethylene terephthalate. In this study, 3-HPA was biosynthesized from formaldehyde and acetaldehyde using deoxyribose-5-phosphate aldolase from Thermotoga maritima (DERATma) and cloned and expressed in Escherichia coli for 3-HPA production. Under optimum conditions, DERATma produced 7 mM 3-HPA from 25 mM substrate (formaldehyde and acetaldehyde) for 60 min with 520 mg/L/h productivity. To demonstrate the one-pot 3-HPA production from methanol and ethanol, we used methanol dehydrogenase from Lysinibacillus xylanilyticus (MDHLx) and DERATma. One-pot 3-HPA production via aldol condensation of formaldehyde and acetaldehyde from methanol and ethanol, respectively, was investigated under optimized reaction conditions. This is the first report on 3-HPA production from inexpensive alcohol substrates (methanol and ethanol) by cascade reaction using DERATma and MDHLx.

Effect of addition of compatibilizer on mechanical, thermal and thermo-mechanical behavior of a polymer blend (PBT/ PBT(G)/ PTT) composite

PurposeThis study aims to reduce the interfacial tension by increasing the better adhesion between different immiscible polymers phases and also to evaluate the mechanical, thermal and thermo-mechanical behavior of the immiscible polymer blends.Design/methodology/approachThe polymer blend composite (PBC) was prepared using a twin-screw extruder followed by injection molding. Two different kinds of PBC with compatibilizer (Ethylene-n-Butylacrylate-Glycidyl methacrylate) of varying compositions like polybutylene terephthalate + poly trimethylene terephthalate and polybutylene terephthalate (30% glass filled) + poly trimethylene terephthalate were prepared and material behavior at various test conditions were studied. The effect of glass fiber reinforcement on polymer blend and the interlocking effect by the compatibilizer between the polymer phases were also assessed.FindingsMechanical behavior of PBC was estimated by tensile, flexural and angular impact tests. Likewise, the thermal deflection was studied with the help of heat deflection temperature test. Thermo-mechanical behavior likes storage modulus, loss modulus and loss tangent were studied using the dynamic mechanical analysis test. Morphological analysis was characterized using field emission scanning electron microscopy.Originality/valueThis in turn makes the process easy to obtain the PBC having inherent mechanical, thermal and thermo-mechanically stable. And, it also enhances the mechanical properties like tensile, flexural and impact strength. Simultaneously, posse’s excellent heat deflection and thermo-mechanical behavior over a temperature range of 35–140ºC at a constant frequency of 5 Hz.

Analysis of Short-Term Prestress Losses in Post-tensioned Structures Using Smart Strands

The proper estimation of prestressing force (PF) distribution is critical to ensure the safety and serviceability of prestressed concrete (PSC) structures. Although the PF distribution can be theoretically calculated based on certain predictive equations, the resulting accuracy of the theoretical PF needs to be further validated by comparison with reliable test data. Therefore, a Smart Strand with fiber optic sensors embedded in a core wire was developed and applied to a full-scale specimen and two long-span PSC girder bridges in this study. The variation in PF distribution during tensioning and anchoring was measured using the Smart Strand and was analyzed by comparison with the theoretical distribution calculated using the predictive equations for short-term prestress losses. In particular, the provisions for anchorage seating loss and elastic shortening loss were reviewed and possible improvements were proposed. A new method to estimate the amount of anchorage slip based on real PF distributions revealed that the general assumption of 3–6-mm slip falls within a reasonable range. Finally, the sensitivity of the PF distribution to a few of the variables included in the equation of the elastic shortening loss was examined. The study results confirmed that the developed Smart Strand can be used to improve the design parameters or equations in PSC structures by overcoming the drawbacks of conventional sensing technologies.

Assessing the Economic Viability of the Plastic Biorefinery Concept and Its Contribution to a More Circular Plastic Sector.

It is widely accepted that plastic waste is one of the most urgent environmental concerns the world is currently facing. The emergence of bio-based plastics provides an opportunity to reduce dependency on fossil fuels and transition to a more circular plastics economy. For polyethylene terephthalate (PET), one of the most prevalent plastics in packaging and textiles, two bio-based alternatives exist that are similar or superior in terms of material properties and recyclability. These are polyethylene furanoate (PEF) and polytrimethylene terephthalate (PTT). The overarching aim of this study was to examine the transition from fossil-based to renewable plastics, through the lens of PET upcycling into PEF and PTT. The process for the production of PEF and PTT from three waste feed streams was developed in the SuperPro Designer software and the economic viability assessed via a discounted cumulative cash flow (DCCF) analysis. A techno-economic analysis of the designed process revealed that the minimum selling price (MSP) of second generation-derived PEF and PTT is 3.13 USD/kg, and that utilities and the feedstock used for the production of 2,5-furandicarboxylic acid (FDCA) needed in PEF synthesis contributed the most to the process operating costs. The effect of recycling PEF and PTT through the process at three recycling rates (42%, 50% and 55%) was investigated and it was revealed that increased recycling could reduce the MSP of the 2G bio-plastics (by 48.5%) to 1.61 USD/kg. This demonstrates that the plastic biorefinery, together with increasing recycling rates, would have a beneficial effect on the economic viability of upcycled plastics.

A Low-Cost Prestress Monitoring Method for Post-Tensioned RC Beam Using Piezoelectric-Based Smart Strand

This study proposes a cost-effective prestress monitoring method for post-tensioned reinforced concrete (RC) beams using a smart strand. Firstly, the concept of a piezoelectric-based smart strand and its implementation for prestress force monitoring are developed. The smart strand is prepared by embedding inexpensive and high-sensitivity electromechanical impedance (EMI) sensors in a steel strand. Next, the feasibility of the proposed method is experimentally verified for prestress force monitoring of a simple supported post-tensioned RC beam. A smart strand prototype is fabricated and embedded into a 6.4 m RC beam which is then prestressed with different levels. For each prestress level, the EMI responses of the smart tendon are measured and the EMI features are extracted for prestress force monitoring. The results showed that the EMI signals of the smart strand showed strong resonant peaks that varied sensitively to the prestress level of the beam. The prestress change in the prestressed RC beam was successfully estimated by using linear regression models of the EMI features.

In-situ hydrogenolysis of glycerol using hydrogen produced via aqueous phase reforming of glycerol over sonochemically synthesized nickel-based nano-catalyst

1,3-Propanediol (1,3-PDO) is a commercially valuable chemical for the production of polytrimethylene terephthalate polymers and polyurethane. In this study, the production of 1,3-PDO was investigated via aqueous phase reforming (APR) and selective hydrogenolysis of glycerol over Ni-Ca/CeO2 catalysts synthesized by sonochemical (Us) and wet impregnation (WI) methods. The experiments were performed in a batch reactor at 20 bar, 230 ℃, and 450 rpm for 1 h. The synthesized catalysts were characterized using XRD, TEM, FESEM, BET, H2-TPR, XPS, CO-chemisorption, and NH3-TPD to better understand the physio-chemical and surface characteristics. The results revealed that sonochemical catalysts showed a larger surface area, smaller crystallite size, low reduction temperature and more homogenous particle distribution than wet impregnation catalysts. For both preparation methods, monometallic Ni/CeO2 catalysts showed the highest activity, whereas Ca modification of Ni/CeO2 catalysts significantly decreased the activity of the catalysts. The highest yield and selectivity of 1,3-PDO were 19.54% and 52.73%, respectively, using Ni/CeO2_Us catalyst. The best catalyst was further utilized for parameters optimization study to observe the effect of varying glycerol concentration (10 to 25 vol.%), temperature (210 to 250 ℃) and pressure (10 to 30 bar) on the yield and selectivity of 1,3-PDO and glycerol conversion. The results demonstrated that the highest yield (19.54%) and selectivity (52.73%) of 1,3-PDO were obtained over 10 vol.%, 230 ℃ and 20 bar with glycerol conversion of 54.26%. This present study provides a promising and economical process of converting glycerol to 1,3-PDO, which has wide applications in the industry.

Weight Reduction of Sea-island-type PTT/PET Conjugate Fiber and Dyeing of Polytrimethylene Terephthalate Flock Microfibers

Weight Reduction of Sea-island-type PTT/PET Conjugate Fiber and Dyeing of Polytrimethylene Terephthalate Flock Microfibers

Effects of Ultrasonic Waves on PTT Dyeing with Disperse Red 60 Dye

In current study, disperse red 60 (DR60) dye was selected for dyeing of Polytrimethylene terephthalate (PTT) under the influence of ultrasonic radiation. For this purpose the disperse dyes were placed under ultrasonic for 15-90 minutes and the particle size determined using DSL, also influence of temperature and time investigated. The results illustrated that ultrasonic has a good power to reduce particle size of the dye and the smallest particle size for the DR60 dye, obtained at the time of 45 minutes and the temperature of 20 ° C. Also we observed pH = 6 is the best pH for the adsorption process. Then the influence of amount of the absorbent and contact time were investigated. All experiments, indicate that ultrasonic has a great effect on adsorption of DR60 dye to PTT. In this research, the adsorption isotherm is well defined by the Nernst model. Then thermodynamic calculations such as Gibbs free energy (ΔG), enthalpy (ΔH), entropy (ΔS) are explained.

Bio-Based Polyester Fiber Substitutes: From GWP to a More Comprehensive Environmental Analysis

The textile industry has lately started exploring the possibility of bio-sourcing for synthetics, notably polyester fiber, in the effort to break from the proven fossil-fuel dependency and decrease the environmental impacts. Traditionally made out of fossil-based polyethylene terephthalate polymer, polyester can be functionally substituted with three bio-based alternatives: bio-polyester, polytrimethylene terephthalate, and polylactic acid fibers. At present, however, there is a lack of studies on the environmental effects of such substitution. We, therefore, performed a comparative, cradle-to-gate life cycle assessment of conventional polyester and those substitutes featuring varying levels of bio-content. The impact assessment was performed with the most recent version of the Environmental Footprint method including some adaptations—using carbon crediting and a different, distance-to-target weighting approach. Bio-sourced fibers are found to cause higher environmental burdens than polyester. Acidification, eutrophication, ecotoxicity, water, and land use increase with the bio-content and are predominantly linked to the first generation feedstock (agriculture and transport). The results on climate change vary with the impact method adaptations, yet do not manage to offset the aforementioned deteriorations. In single scores, only three out of nine substitutes are found to perform comparably, while the rest perform significantly worse than the incumbent fiber.

Development of biaxial stretchable nonwoven paddings using novel polymeric fibers

Nonwoven paddings with superior stretch and recovery properties in both directions with good thermal insulation properties were developed for application in winter clothes. Paddings were developed using a self‐crimping elastic fiber composed of both polyethylene terephthalate (PET) and polytrimethylene terephthalate (PTT) polymers, polyester fiber balls, polypropylene fiber balls, along with bicomponent as binder fibers at different blending ratios through carding, postthermal bonding, and gluing process. Developed paddings were characterized and analyzed for their biaxial stretch and recovery behavior, elongation under tensile load, stiffness, thermal insulation, and washing stability. In addition, energy loss was calculated and reported from hysteresis curve obtained during 40% loading (stretch) and unloading (recovery) cycle. The results were statistically evaluated to determine whether fiber types and blend ratios have significant effect on nonwoven paddings properties. This study indicates that nonwoven padding composed of naturally crimped elastic fibers: binder fibers (50:50) has ability to stretch around 120‐140% in both directions, 95% total recovery with minimal energy loss upon 40% stretch and recovery cycle, and it has sustainable tensile breaking load around 11 N along cross direction and 20 N along machine direction. It has stiffness load 5 N which is flexible enough for required applications, possesses good thermal insulation properties, and holds their structural properties after five washing cycles. From statistical analysis, ANOVA results exhibited that the used fiber types and their weight percentages significantly affect stretch and recovery, other properties of nonwoven paddings for required application.

Strain/Stress Self-Sensing Precast-Box Culvert: Smart Element Design, and Experimental Verification

The present study involves the smart precast box culvert, which can sense the strain and stress achieved based on the fiber optic sensor embedded into the fiber-reinforced polymer. These culverts (2.00 × 2.00 × 2.00 m) was investigated experimentally with different seven trial load tests subject to join the dual box culvert using two steel strand and two smart steel strand (CH2&CH3) which is connected to fiber-reinforced polymer strain sensor for analyzing deformation sensor, line load strain, stress region, and stress–strain self-sensing of the culverts. From the monitored results in this self-sensing static load test, the maximum deformation sensor was 131.75 µɛ at the lower smart steel strand (CH3) and the cracks (0.10 mm) initiated on the roof slab of the culverts for a specimen due to bending moment in the culvert not exceeded its moment capacity because the applied load was smaller than the ultimate load. This paper proposes a series of fiber-reinforced polymer strain sensors to connect to the smart strand to completely meet the culvert’s requirements, and their sensing performance is come out. This study, therefore, implied that the experimental finding of the fiber-reinforced polymer strain sensors has the potential to monitor the structural health over time.

Advances in Research on Production of 1, 3-PD by immobilized technology

1,3-propanediol (abbreviated as 1,3-PD) is an important chemical raw material, which is widely used in printing and dyeing, coatings, inks, pharmaceuticals, antifreeze, lubricants, etc. Used as a monomer to synthesize new polyester material PTT (polytrimethylene terephthalate) has attracted wide attention The first paragraph after a heading is not indented (Bodytext style). The production methods of 1,3-PD mainly include chemical synthesis and microbial fermentation. Due to the shortage of petrochemical resources, the production of 1,3-PD by microbial fermentation has become a hotspot at home and abroad. Among them, the application of immobilization technology and the selection of immobilized carrier materials have a good improvement in the efficiency of 1,3-PD produced by fermentation.

Investigation on the performance properties of polytrimethylene terephthalate (PTT) based staple fibers and cotton blended OE-rotor yarns

In this study, firstly, it is aimed to spin PTT (Polytrimethylene Terephthalate) based staple Sustans® fibers together with cotton in Open-End rotor yarn production system. In this way, it is aimed to transfer the positive properties of Sustans® fibers such as good elasticity, good dimensional stability, low static electrification and soft hand to the staple yarn structure with a high efficiency spinning technique. In this context, using 5 different ratios of Sustans®/Cotton blends and 100% Cotton, 6 different rotor yarns with Ne 8.25 (71.6 tex) were produced and the quality characteristics of these yarns were tested. In the study, Sustans®/Cotton blends were successfully spun with the Open-End rotor system. As a result, compared to 100% cotton, it was observed that the elongation at break, unevenness, yarn defects and hairiness values were better for yarns containing Sustans® fibers, while the strength values were slightly lower. The optimum blend ratio was concluded to be 50/50% Sustans®/Cotton for the open-end spinning technique.

Thermally induced end-group-capturing as an eco-friendly and general method for enhancing the fire safety of semi-aromatic polyesters

Despite the excellent overall performance, the application of polyesters is severely restricted by their inherently high flammability. Although many gratifying results have been achieved through different fire-safety methods, customization is still needed for every specific polymer, thus a generally applicable method is highly desired. Herein, we developed an eco-friendly and general fire-safety method for semi-aromatic polyesters based on the “end-group-capturing” concept. The functional monomer was chemically incorporated into the main chains of a series of semi-aromatic polyesters with similar structures (i.e., polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT) and polybutylene terephthalate (PBT)), and the specific contribution of the fire-safety method was investigated comprehensively. The results showed that the fire safety of all the copolyesters were efficiently improved, while interestingly, the fire safety gradually declined with the increase of the methylene group numbers in their molecular chains. The reason behind this phenomenon was comprehensively studied by both theoretical calculation and experiments. The increasing cyclization tendency of the copolyesters derived from the increase of the methylene group numbers was proved to be responsible for the decrease of the fire safety. The successful application and in-depth mechanism revealed here provide theoretical supports for the development of novel fire-safety polymeric materials.

Evaluation of the crimp formability of side-by-side PLA/PTT bicomponent fibers

To explore the feasibility of developing bio-based elastic fibers, bio-based polylactide (PLA) and polytrimethylene terephthalate (PTT) were selected for fabrication of side-by-side bicomponent fibers using bi-constituent melt-spinning technology. The structure development and performance of PLA/PTT bicomponent fibers was investigated using thermal mechanical analysis, differential scanning calorimetry, and wide-angle X-ray diffraction in order to evaluate the crimp formability of PLA/PTT bicomponent fibers. The PLA and PTT components could form regular boundary structure and exhibit excellent interface compatibility by regulation of the rheological behavior of the two melts. In the fiber forming process, the PTT component in PLA/PTT bicomponent fibers experienced higher tensile stress, and thereby enhanced the crystal and oriented structure development, while the structural evolution of the PLA component was inhibited. The difference in the structure of the two components causes the imbalance force existence in the PLA/PTT fibers, which is the main reason of fiber crimp. In addition, the crimp formability of the PLA/PTT fibers could be enhanced by expanding the shrinkage stress difference between the two components, which could be realized by increasing the PTT ratio in PLA/PTT bicomponent fiber or draw ratio. The maximum crimp extension that could be achieved was 85% for the bicomponent fibers with PLA30/PTT70 ratio at a draw ratio of 4.2.

Ecological and cleaner process for dyeing bicomponent polyester filaments (PET/PTT) using ecological carriers: analysis of dyeing performance.

Thanks to their excellent properties, bicomponent filaments, in particular, polyethylene terephthalate (PET)/polytrimethylene terephthalate (PTT) are more and more used in stretchable clothing. Despite the researchers' efforts, the dyeing of these filaments still presents several problems which should be resolved. Manufacturers must choose between dyeing polyester under pressure at high temperatures (close to 130 °C) to have less toxic and cheaper textile effluents and/or dyeing at low temperatures (not exceeding 100 °C) which needs the use of toxic carriers. This paper presents a new opportunity and the feasibility of dyeing bicomponent polyester filaments using an economic and clean process at a temperature equal to 100 °C and by replacing toxic carriers by ecological ones. Three kinds of ecological carriers, namely o-Vanillin, p-Vanillin and Coumarin, are used to improve the dyeing performance of bicomponent filaments with three disperse dyes having different molecular weights. They were compared to three conventional ones largely used in industry. The effect of each carrier on dyeing performance (dye bath exhaustion, color strength and CIELab coordinates) was then investigated. The obtained results prove that ecofriendly carriers constitute a good solution to replace the toxic ones and allow to obtain the same, or even better dyeing performance and fastness properties.

Comparative analysis of cotton covered elastomeric hybrid yarns and denim fabric properties

In recent decades, consumer expectations and behavior have altered, focusing on more comfortable, well-fitting clothes. Wearing a slim-fitting garment helps to move more freely. Different elastomeric polymers are being introduced as a core constituent of the yarn to make denim fabric more comfortable during movement. The use of elastic material ensures that the material is stretchable and recoverable. The performance of several elastomeric hybrid yarns has been investigated in the first section of this study. Here, polyethylene terephthalate/polytrimethylene terephthalate (PET/PTT (T400®)), polytrimethylene terephthalate (PTT (Solotex®)), polybutylene terephthalate (PBT), and Lycra® (elastane) were used as the core component of the core and dual core-spun yarns. After that, 3/1 Z twill denim fabrics were made with these as weft yarns, and the fabric’s performance was assessed. It is found that dual core-spun yarns were shown to have lower strength than core-spun yarns, while it had a higher elongation value. PTT/PBT dual core-spun yarn had less unevenness and hairiness than yarn made solely of elastane. PBT in the core of the weft yarns provided strong strength, dimensional change, and stiffness qualities in the fabric. In contrast, elastane in the core of the weft yarns provided good elastic performance. Yarn and fabric performance for the hybrid yarns were statistically significant at a significance level of 0.05.

Sequential fed-batch fermentation of 1,3-propanediol from glycerol by Clostridium butyricum DL07

The demand for 1,3-propanediol (1,3-PDO) has increased sharply due to its role as a monomer for the synthesis of polytrimethylene terephthalate (PTT). Although Clostridium butyricum is considered to be one of the most promising bioproducers for 1,3-PDO, its low productivity hinders its application on industrial scale because of the longer time needed for anaerobic cultivation. In this study, an excellent C. butyricum (DL07) strain was obtained with high-level titer and productivity of 1,3-PDO, i.e., 104.8g/L and 3.38g/(L•h) vs. 94.2g/L and 3.04g/(L•h) using pure or crude glycerol as substrate in fed-batch fermentation, respectively. Furthermore, a novel sequential fed-batch fermentation was investigated, in which the next bioreactor was inoculated by C. butyricum DL07 cells growing at exponential phase in the prior bioreactor. It could run steadily for at least eight cycles. The average concentration of 1,3-PDO in eight cycles was 85g/L with the average productivity of 3.1g/(L•h). The sequential fed-batch fermentation could achieve semi-continuous production of 1,3-PDO with higher productivity than repeated fed-batch fermentation and would greatly contribute to the industrial production of 1,3-PDO by C. butyricum. KEY POINTS: • A novel C. butyricum strain was screened to produce 104.8g/L 1,3-PDO from glycerol. • Corn steep liquor powder was used as a cheap nitrogen source for 1,3-PDO production. • A sequential fed-batch fermentation process was established for 1,3-PDO production. • An automatic glycerol feeding strategy was applied in the production of 1,3-PDO.

Strengthening the TCA cycle to alleviate metabolic stress due to blocking by-products synthesis pathway in Klebsiella pneumoniae.

1,3-Propanediol (1,3-PDO) is an important synthetic monomer for the production of polytrimethylene terephthalate (PTT). Here, we engineered Klebsiella pneumoniae by a multi-strategy to improve 1,3-PDO production and reduce by-products synthesis. First, the 2,3-butanediol (2,3-BDO) synthesis pathway was blocked by deleting the budB gene, resulting in a 74% decrease of 2,3-BDO titer. The synthesis of lactate was decreased by 79% via deleting the ldhA gene, leading to a 10% increase of 1,3-PDO titer. Further, reducing ethanol synthesis by deleting the aldA gene led to a 64% decrease of ethanol titer, and the 1,3-PDO titer and yield on glycerol increased by 12 and 10%, respectively. Strengthening the TCA cycle by overexpressing the mdh gene improved 1,3-PDO synthesis effectively. Under 5-L fed-batch fermentation conditions, compared to wild type strain, the production of 2,3-BDO, lactate and ethanol in the mutant strain decreased by 73, 65 and 50%, respectively. Finally, the production of 1,3-PDO was 73.5g/L with a molar yield of 0.67mol/mol glycerol, improved 16% and 20%, respectively. This work provides a combined strategy for improving 1,3-PDO production by strengthening the TCA cycle to relieve metabolic stress by deleting genes of by-products synthesis, which was also beneficial for the extraction and separation of downstream products.