Poly Trimethylene Terephthalate Research Articles

Development of sustainable dual core-spun yarns using several filaments and recycled cotton sourced from pre-consumer fabric waste

Textile industries are now focusing on sustainable issues in manufacturing operations to save the environment. The study focuses on the use of cotton fibers (recycled) sourced from fabric (knitted) waste (pre-consumer) to manufacture elastic yarn (dual-core) for denim fabric. The study involves the production of yarns (dual-core) using a redesigned ring spinning method with different elastomeric components, including T400® (Polyethylene terephthalate)/Polytrimethylene terephthalate), Polybutylene terephthalate (PBT), Polyester (PES), Lycra® (elastane), virgin cotton and cotton (recycled) fiber. The study investigates various yarn (Ne 18/1) characteristics such as strength, IPI (imperfection index), elongation %, unevenness %, and hairiness. It is noticed that the elongation and strength of recycled yarn (double core) are lower and IPI (Imperfection index), unevenness %, and hairiness values are higher than 100 % cotton (virgin) yarn (double core). One-way ANOVA (statistical analysis) is employed to assess the significance of differences among yarns manufactured from various core materials and found significant variation for all characteristics. Additionally, the article introduces the MOORA (multi-objective optimization based on ratio analysis) technique as a decision-making tool to determine the best yarn among three alternatives (PES yarn, PBT yarn, and T400 yarn) based on their properties, considering attributes and finding T400 filament containing yarn as the best option. The study introduces a sustainable approach using recycled cotton in yarn (double core) production and employs decision-making tools to assess and rank the performance of different yarn alternatives.

Cold crystallization of polytrimethylene terephthalate and copolymers

The melt of crystalline polymers normally crystalize on cooling and the polymer melts with low critical cooling rate would easily solidify as glass during cooling to their glass transition temperature (Tg). The glassy process exhibits variety within each kind of polymer melts in the slope of the viscosity-temperature visibility, and the rate of the excess conformational entropy in the polymer melt over the crystalline phase changes in the Tg approaching. Polytrimethylene terephthalate (PTT) and a series of polytrimethylene terephthalate copolyesters (PTTG) with different molar ratios of 1,3-propylene glycol (1,3-PDO) to 1,4-cyclohexanedimethanol (1,4-CHDM) were synthesized to modify the chain flexibility and the critical cooling rate. The glassy samples were obtained via quenching the melts of PTT and copolymers below the Tg to characterize the cold crystallization behaviors. The evolutions of the crystalline structure of the amorphous samples were in situ investigated via DSC and simultaneous WAXS/SAXS approaches during heating. The polymer chain dynamics and the critical cooling rates of the PTT and copolymers were estimated by rheological testing and DSC characterization. The results indicate that the chain conformation adjustment of PTT and copolymers is relate to the comonomers in the copolymers, and the cold crystallization behaviors can be divided into three temperature ranges during heating. The first involves rapid transition from a pre-ordered phase to a crystalline phase, the second is the adjustment of defects in an imperfect crystalline phase, and the third may refer crystal reorganization before melting. The crystallization ability of the samples could be due to the ability of chain conformation adjustment with comonomer content till the crystallization is no longer obvious during heating. The cold crystallization behaviors of the samples were discussed based on the polymer chain dynamics and it is convinced that would be helpful to understand the crystallization and processing of polymers.

Studies on (polytrimethylene terephthalate)/graphene oxide/f-MWCNT hybrid nanocomposites

Natural resource-driven approaches to bioengineering plastics are being developed to compete in the automobiles, power, and other sectors. Polytrimethylene terephthalate (PTT) is a particular of them, and it was chosen for the current investigation to build an advanced nanocomposite material. Using a twin-screw micro compounder, injection moulded PTT/Graphene-Oxide (GO)/Carboxyl functionalized Multiwall Carbon nanotube (f-MWCNT) hybrid nanocomposites were prepared. The impact of GO and f-MWCNT reinforcement on the composite’s thermal and mechanical characteristics of hybrid nanocomposites was examined. GO was synthesized from the graphite powder by modified Hummer’s method and MWCNTs were functionalized using the concentrated sulfuric acid (H2SO4) and nitric acid (HNO3) with a volume ratio of 3:1 in an ultrasonic bath at room temperature. In all formulations, the investigation was done at a constant filler amount of 2 wt%. To understand the chemical interaction between PTT and nanofiller, Raman spectroscopy was used and to examine the state of dispersion, scanning electron microscopy (SEM) was systematically analysed. In comparison to pristine PTT, the water absorption, tensile strength, flexural strength and impact strength of hybrid nanocomposites were improved marginally. It was also observed that GO has more prominent in increasing the mechanical properties of the hybrid and f-MWCNT in thermal properties. The 3-D geometrical bridge between GO (2-D) and f-MWCNT (1-D) made the hybrid more dispersible and effective for different applications.

Electro-Oxidation of Diols in Polymer Recycling: Facilitating Separation and Refining Products

Increasing environmental awareness has highlighted the importance of plastic recycling and rightfully so, considering plastic pollution and an ever-increasing consumption of plastic products. Currently, numerous recycling strategies are being investigated with varying approaches depending on the type of polymer [1]. One attractive process is the chemical recycling of polyesters via alkaline hydrolysis which produces the dicarboxylic acid salts and diols of the respective polyester. The dicarboxylic acids can be separated by crystallization, while the diol separation remains a challenge. A process concept is proposed that utilizes two electrochemical separation technologies to process the polyester hydrolysis solution. A selective electro-oxidation of diols is proposed to mediate and simplify the challenging diol separation. The dicarboxylic acids can be crystalized using an electrochemical pH shift crystallization, which can simultaneously provide the base required for the alkaline hydrolysis of polyesters.The electrochemical pH shift crystallization utilizes water electrolysis in a membrane-separated parallel plate electrolyzer. The pH of the anode and cathode chambers is shifted towards acidic and basic pH values, respectively [2]. The acidification of the anolyte shifts the dissociation equilibrium of the respective dicarboxylic acid salt to the less water-soluble, fully protonated dicarboxylic acid. Crystallization is carried out within the electrolyzer, while the alkaline catholyte solution may be applied in the polyester hydrolysis.To circumvent the challenging removal of diols from aqueous solution [3], a selective electro-oxidation of said diols is proposed. The oxidation towards hydroxycarboxylic acids or dicarboxylic acids facilitates simplified separation processes such as pH shift extraction or crystallization, respectively. Rather than a closed-loop recycling towards both monomers, the proposed process suggests an upgrading of the diols to value-added molecules and crystallization of the dicarboxylic acid, which facilitates and simplifies separation.The study investigates the selective electro-oxidation of diols from three different polyesters: polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), and polybutylene succinate (PBS). A three-electrode setup utilizing plate electrodes as working electrodes is used in a custom cyclic voltammetry cell. Electro-oxidation is carried out in 1M KOH as electrolyte with diol concentrations ranging from 0.2 to 1M. Following the electrocatalyst activity studies, the selectivity of the electro-oxidation utilizing the most promising catalyst is studied in membrane-separated parallel plate electrolyzer experiments. A custom Luggin-Haber capillary setup monitors and controls the oxidation potential during the experiment. This presentation features the preliminary results of plate electrode catalysts’ electro-oxidation of three different diols in alkaline media. Selectivity studies for the oxidation of the three diols (ethylene glycol, 1,3-propane diol, and 1,4-butane diol) in the membrane-separated parallel plate electrolyzer are presented.[1] Hamad, K., Kaseem, M., & Deri, F. (2013). Recycling of waste from polymer materials: An overview of the recent works. Polymer Degradation and Stability, 98(12), 2801–2812. DOI: 10.1016/j.polymdegradstab.2013.09.025[2] Kocks, C., Wall, D., & Jupke, A. (2022). Evaluation of a Prototype for Electrochemical pH-Shift Crystallization of Succinic Acid. Materials (Basel, Switzerland), 15(23), 8412. DOI: 10.3390/ma15238412[3] Garcia-Chavez, L. Y., Hermans, A. J., Schuur, B., & Haan, A. B. de (2012). COSMO-RS assisted solvent screening for liquid–liquid extraction of mono ethylene glycol from aqueous streams. Separation and Purification Technology, 97, 2–10. DOI: 10.1016/j.seppur.2011.11.041

Evaluation of enzymatic depolymerization of PET, PTT, and PBT polyesters

Millions of tons of waste polyester plastics, including polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), and polybutylene terephthalate (PBT), end up in the environment as soil and water contaminants. Recent advances in enzymatic polyester degradation have motivated researchers toward the biorecycling of plastic wastes. Leaf-branch compost cutinase (LCC) enzymes have been proven to be effective in the biodegradation of PET. This study focuses on enzymatic depolymerization of waste PET, PTT, and PBT materials by using an ICCG variant of LCC (LCCICCG) produced from Escherichia coli BL21(DE3). The degradation efficiency of the polyesters was determined by the monomer terephthalic acid (TPA) released from the depolymerization reaction. It was found that the most efficient depolymerization was achieved for PET, followed by PTT and PBT. A kinetic model based on Langmuir adsorption and the Michaelis-Menten equation was developed to describe the enzymatic depolymerization of PET, PTT, and PBT with various enzyme and substrate loadings. The model simulation results revealed that the LCCICCG enzyme loading should be linearly increased as the work capacity of the polyester substrate increases. A specific enzyme loading of 0.91 mg/g PET is suggested to achieve 90% depolymerization of PET within three days. The experimental data and model simulation results can be used to help further engineer the enzyme and process to achieve a complete biodegradation of polyester wastes at a large scale.

A flexible triboelectric nanogenerator based on PVA/PTT/LiCl conductive hydrogel for gait monitoring in basketball

Recently, wearable flexible sensors for intelligent sports monitoring have attracted much attention. In this work, we designed the polyvinyl alcohol (PVA)/polytrimethylene terephthalate (PTT)/LiCl hydrogel to act as the flexible conductive of triboelectric nanogenerator (PPL-TENG). Significantly, the PPL-TENG device has high transparency and stretchability, demonstrating excellent ability in complex mechanical energy harvesting. From the results, the PPL-TENG achieve the maximum power density of 159.6 µW cm−2. In addition, the PVA/PTT/LiCl hydrogel exhibits good mechanical properties, thus endowing PPL-TENG devices with excellent application value. Also, the electrical output of PPL-TENG exhibits good stability and excellent fast charging capability. In addition to mechanical energy harvesting, PPL-TENG also has excellent sensing performance and can be used as a self-powered sensor for basketball motion monitoring. After experimental testing, PPL-TENG can recognize the characteristics of body joints and gait in basketball, which will play an auxiliary role in basketball sports. This research will promote the development of intelligent wearable sports devices.

Waterless dyeing of polytrimethylene terephthalate and polybutylene terephthalate fabrics via supercritical carbon dioxide

In this study, polytrimethylene terephthalate (PTT) and polybutylene terephthalate (PBT) samples were dyed n supercritical carbon dioxide (scCO2) medium. Dianix Dry Blue XF2 and CI Disperse Blue 79 were used for dyeing. Pressure and time optimisation trials were conducted, maintaining the temperature constant based on the optimal results obtained from these trials. The color, fastness, and tensile strength values were assessed. For both PTT and PBT fabrics, the closest color values to conventional dyeing were achieved when dyed with CI Disperse Blue 79 at 85 °C and 25 MPa, and with Dianix Dry Blue XF2 at 70 °C and 25 MPa. Notably, when compared to conventionally dyes samples, darker colors were obtained in scCO2 medium after 70 °C when dyeing with Dianix Dry Blue XF2 and after 85 °C when dyeing with CI Disperse Blue 79 compared to conventionally dyed samples.

Biosynthesis of 1,3-Propanediol via a New Pathway from Glucose in Escherichia coli.

1,3-Propanediol (1,3-PDO), an important dihydric alcohol, is widely used in textiles, resins, and pharmaceuticals. More importantly, it can be used as a monomer in the synthesis of polytrimethylene terephthalate (PTT). In this study, a new biosynthetic pathway is proposed to produce 1,3-PDO using glucose as a substrate and l-aspartate as a precursor without the addition of expensive vitamin B12. We introduced a 3-HP synthesis module derived from l-aspartate and a 1,3-PDO synthesis module to achieve the de novo biosynthesis. The following strategies were then pursued that included screening key enzymes, optimizing the transcription and translation levels, enhancing the precursor supply of l-aspartate and oxaloacetate, weakening the tricarboxylic acid (TCA) cycle, and blocking competitive pathways. We also used transcriptomic methods to analyze the different gene expression levels. Finally, an engineered Escherichia coli strain produced 6.41 g/L 1,3-PDO with a yield of 0.51 mol/mol glucose in a shake flask and 11.21 g/L in fed-batch fermentation. This study provides a new pathway for production of 1,3-PDO.

Heterologous 1,3-Propanediol Production Using Different Recombinant Clostridium beijerinckii DSM 6423 Strains.

1,3-propanediol (1,3-PDO) is a valuable basic chemical, especially in the polymer industry to produce polytrimethylene terephthalate. Unfortunately, the production of 1,3-PDO mainly depends on petroleum products as precursors. Furthermore, the chemical routes have significant disadvantages, such as environmental issues. An alternative is the biobased fermentation of 1,3-PDO from cheap glycerol. Clostridium beijerinckii DSM 6423 was originally reported to produce 1,3-PDO. However, this could not be confirmed, and a genome analysis revealed the loss of an essential gene. Thus, 1,3-PDO production was genetically reinstalled. Genes for 1,3-PDO production from Clostridium pasteurianum DSM 525 and Clostridium beijerinckii DSM 15410 (formerly Clostridium diolis) were introduced into C. beijerinckii DSM 6423 to enable 1,3-PDO production from glycerol. 1,3-PDO production by recombinant C. beijerinckii strains were investigated under different growth conditions. 1,3-PDO production was only observed for C. beijerinckii [pMTL83251_Ppta-ack_1,3-PDO.diolis], which harbors the genes of C. beijerinckii DSM 15410. By buffering the growth medium, production could be increased by 74%. Furthermore, the effect of four different promoters was analyzed. The use of the constitutive thlA promoter from Clostridium acetobutylicum led to a 167% increase in 1,3-PDO production compared to the initial recombinant approach.

Investigation of Performance Properties of Denim Fabrics Containing Cotton/Sustans® Blend Rotor Yarn

It is common to use open-end rotor yarn in the production of denim fabric, which is preferred by people of all ages and social status due to its durability and comfort. Recently, the demand for stretch denim fabrics that can take the body's shape due to the elastic fibers in its structure has been increasing. However, producing elastane-containing yarns in the rotor spinning system is not as practical as ring spinning. For this reason, this study aimed to use the staple Sustans® fibers with high elasticity in the rotor spinning system together with cotton fibers and reflect the good elasticity and elongation properties of Sustans® fibers to the rotor yarns and denim fabrics. In the study, the staple Sustans® fibers based on PTT (Polytrimethylene Terephthalate) were spun with cotton fibers in the rotor spinning system. Then denim fabrics were produced using these yarns in the weft. Later, strength (breaking and tear), dimensional stability (dimensional change after washing, fabric elasticity and growth), abrasion resistance and pilling tests were applied to the produced denim fabrics. Thus, the effects of using Sustans® fibers on the strength, dimensional stability, abrasion and pilling properties of denim fabrics were analyzed. As a result of the study, the dimensional change and growth values after washing were developed by using Sustans®. Although good dimensional stability was observed in the samples, the degree of elasticity was lower than expected. The use of Sustans® at rates of 50% and above improved the pilling values of the fabrics. In addition, it has been determined that the use of Sustans® in terms of abrasion resistance has a more positive effect at the end of long wear periods.

Fault Assessment in Piezoelectric-Based Smart Strand Using 1D Convolutional Neural Network

The smart strand technique has been recently developed as a cost-effective prestress load monitoring solution for post-tensioned engineering systems. Nonetheless, during its lifetime under various operational and environmental conditions, the sensing element of the smart strand has the potential to fail, threatening its functionality and resulting in inaccurate prestress load estimation. This study analyzes the effect of potential failures in the smart strand on impedance characteristics and develops a 1D convolutional neural network (1D CNN) for automated fault diagnosis. Instead of using a realistic experimental structure for which transducer faults can be hard to control accurately, we adopt a well-established finite element model to conduct all experiments. The results show that the impedance characteristics of a damaged smart strand are relatively different from other piezoelectric active sensing devices. While the slope of the susceptance response is widely accepted as a promising fault indicator, this study shows that the resistance response is more favorable for the smart strand. The developed network can accurately diagnose the potential faults in a damaged smart strand with the highest testing accuracy of 94.1%. Since the network can autonomously learn damage-sensitive features without pre-processing, it shows great potential for embedding in impedance-based damage identification systems for real-time structural health monitoring.

Overview of the mechanical, thermal and barrier properties of biobased and/or biodegradable thermoplastic materials

This study gives an overview of the most relevant processing and performance properties of a wide selection of biobased and biodegradable plastic materials that are currently commercially available. It provides the most extensive and up-to-date scientific overview of critical properties of biobased and biodegradable plastics. Materials that are tested include fully biobased polymers (polylactic acid, polyethylene, polyamide 10,10 and a range of polyhydroxy alkanoates), partially biobased polymers (polybutylene succinate, polybutylene succinate adipate, cellulose acetate, cellulose acetate propionate, polyethylene terephthalate, polytrimethylene terephthalate, an isosorbide based polycarbonate, a thermoplastic urethane and a starch based blend) and a number of fossil-based materials (polycaprolactone, polybutylene adipate terephthalate, polyglycolic acid and polypropylene). The mechanical (tensile, flexural, impact resistance and hardness), thermal (glass transition temperature, melting temperature, melt-flow index and haul-off force) and barrier (oxygen transmission rate, water vapour transmission rate) properties of all these materials were measured and are presented in a comprehensive overview. This overview shows that the majority of functionalities that are currently being offered by fossil based polymers can be met by biobased alternatives and by biodegradable materials if this is considered to be favourable at end-of-life.

Electromechanical impedance-based prestress force prediction method using resonant frequency shifts and finite element modelling

The piezoelectric-based smart strand technique could effectively monitor the prestress (PS) force in post-tensioned systems. In the previous study, the PS force was predicted by supervised regression models where the relationship between the EMI feature and the PS force was pre-determined through real-scale experiments. Nonetheless, obtaining the EMI response from an operating structure under damaged states is challenging and costly. To solve this shortcoming, this study proposes a simple alternative method to predict the PS force in the smart strand without conducting preliminary tests on a real-scale structure. The idea is to utilize a reliable numerical model corresponding to the target structure to develop a regression-based PS force prediction model. The experimental validation shows that the proposed methodology can accurately predict the PS force in the smart strand. Since the proposed method does not require experimental EMI data under damaged states, it is promising for practical applications on existing structures.

Experimental and theoretical analysis of polymer blend composites using Weibull distribution

ABSTRACT In the present work, the mechanical and thermal behaviors of Poly Butylene Terephthalate, Poly Trimethylene Terephthalate and Poly Butylene Terephthalate (30% Glass filled) polymer and polymer blend composites were studied. Reliability analysis on tensile strength and flexural strength for the polymers and polymer blend composites at different cross-head speeds was done by Weibull distribution methodology. By using Weibull distribution (Two parameters), the theoretical tensile and flexural strength values were determined for the polymers and polymer blend composites at different cross-head speeds. Weibull analysis revealed good correlation between experimental mechanical strength values at varying load conditions with uniform strength distribution. The probability functions indicated good correlation between the cumulative density and strength of the polymer blends suggesting improved thermal stability and reduction in loss of material mass. A thermal scan to determine the the mass loss, glass transition temperature (Tg), melting and decomposition, revealed improved adhesion and enhanced constituent miscibility while the fractography indicated increased interfacial bonding strength and reduced phase tension. The improved adhesion between the polymer phases was caused by the compatibilizer which also improved the mechanical properties and thermal stability.

Analytical impedance model for piezoelectric‐based smart Strand and its feasibility for prestress force prediction

Analytical impedance model for piezoelectric‐based smart Strand and its feasibility for prestress force prediction

Upcycled Polypropylene and Polytrimethylene Terephthalate Carpet Waste in Reinforcing Cementitious Composites

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Improvement of 1,3-propanediol production from crude glycerol by co-cultivation of anaerobic and facultative microbes under non-strictly anaerobic conditions

BackgroundNatural microbial consortia could efficiently produce 1,3-propanediol (1,3-PDO), a most promising bulk biochemical derived from glycerol that can be used as a monomer in the synthesis of polytrimethylene terephthalate (PTT). While natural microbial communities are made up of a diverse range of microbes with frequently unknown functions, the construction of synthetic microbial consortia allows for the creation of more defined systems with lower complexity.ResultsIn this study, the synthetic microbial consortia were constructed by combining facultative microbes of Klebsiella pneumoniae DUT2 (KP) and/or Escherichia coli DUT3 (EC) cultures with the strictly anaerobic microbe of Clostridium butyricum DUT1 (CB) cultures under micro-aerobic conditions. The function of EC and KP during the fermentation process was to deplete oxygen and create an anaerobic environment for CB. Furthermore, KP competes with CB for the consumption of crude glycerol and the production of 1,3-PDO. The interaction of commensalism and competition resulted in the construction of synthetic microbial consortia capable of efficiently converting crude glycerol to 1,3-PDO even under micro-aerobic conditions. In a batch fermentation, the synthetic CB:KP co-culture at an initial abundance ratio of 92.5:7.5, yielded a maximum 1,3-PDO concentration of 52.08 g/L, with a yield of 0.49 g/g and a productivity of 1.80 g/(L.h), which increased by 10%, 9%, and 12%, respectively, when compared to the CB mono-culture under strictly anaerobic conditions. The final 1,3-PDO concentration, yield, and productivity by the synthetic CB:KP consortia increased by 16%, 19%, and 84%, respectively, when compared to the KP mono-culture. At an initial abundance ratio of 85:7.5:7.5, the synthetic CB:KP:EC co-culture achieved the highest 1,3-PDO flux of 49.17%, while 7.43%, 5.77%, 3.15% 4.24%, and 2.13% of flux was distributed to butyric acid, acetic acid, lactic acid, ethanol, and succinic acid pathways. In a fed-batch fermentation, the synthetic CB:KP:EC co-culture demonstrated a maximum 1,3-PDO concentration of 77.68 g/L with a yield of 0.51 g/g which is 30% and 13% higher than the production by the CB mono-culture at 0.02 vvm (nitrogen volume/culture volume/min) N2 supply. The initial abundance of CB, which is guaranteed to be at least 85%, enables efficient 1,3-PDO production from crude glycerol via the development of synthetic microbial consortia.ConclusionThe synthetic microbial consortia demonstrated excellent performance on 1,3-propanediol production under micro-aerobic conditions through the interaction of commensalism and competition. The experimental results demonstrated the potential benefit of using synthetic microbial consortia to produce 1,3-propanediol from crude glycerol.

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.