Bis 2-hydroxyethyl Terephthalamide Research Articles

Catalytic recycling of PET waste bottles into a value-added amide monomer using a heterogeneous niobium pentoxide nanocatalyst

Using a diverse heterogeneous nanocatalyst, aminolysis presents a promising approach for the chemical recycling of discarded PET waste bottles into a valuable monomer bis(2-hydroxyethyl) terephthalamide (BHETA). This study reports the...

Improvement in BHETA yield by aminolysis and its application in hot melt adhesive

Polyethylene terephthalate (PET) recycling has been carried out by various methods, e.g., mechanical recycling, chemical recycling, and energy recovery method. In this study, chemical recycling of PET was carried out by aminolysis using ethanolamine and converted into bis(2-hydroxyethyl) terephthalamide (BHETA). We have studied the effective polymeric catalysis of the aminolytic depolymerization of waste polyethylene terephthalate (PET) using sulfated polyborate producing a broad range of crystalline terephthalamides. The reaction was performed by varying the PET: ethanolamine ratio, reaction time and catalyst. Recycled PET bottles, film, and fibres were used for conversion. A yield of 95 % was obtained for PET: ethanolamine ratio of 1:4 (w/w), with 4 h reaction time, at 160oC with sulfated polyborate as a catalyst. BHETA was characterized with FTIR, 1H,13C NMR, and DSC analysis. BHETA further gets reacted with dimer acid along with Ethylenediamine (EDA) at different molar ratios which produces polyesteramide (PEA) based hot melt adhesive (HMA). Thermal, mechanical, and rheological tests are performed and compared with traditional HMA. The effect on the properties of the hot melt adhesive, such as mechanical properties: tensile strength, shore D hardness, elongation at break; thermal properties: glass transition temperature (Tg), melting temperature (Tm), the heat of crystallization (Hc), crystallization temperature (Tc); adhesion properties: lap shear strength (LSS) and T-peel strength (TPS); rheological properties and degree of crystallinity were investigated. It was observed that the mechanical and thermal properties are increased by optimizing the concentration of BHETA. These HMA materials may have the capacity of being eco-friendly and have high adhesion properties.

Upcycling of waste PET into high-performance and multifunctional materials

Recycling waste plastics has brought a global upsurge, but there are still troubles of high-energy consumption and low utilization rates in the recovery process. Here, we present a low-energy consumption route for recycling waste PET into high-value-added and high-performance materials. Bis(2-hydroxyethyl) terephthalamide (BHETA) containing several polar groups is obtained by aminolysis of PET under mild conditions and it is prepared as a BHETA-based adhesive with considerable urethane bonds. Outstanding adhesion properties (1.34 MPa) are maintained in different climatic conditions and organic solutions. To further improve the mechanical properties of the adhesive, subsequently, a multifunctional adhesive with abundant cross-linking structures driven by hydrogen bonding and π-π stacking interactions was prepared by introducing PEG400, which exhibits strong adhesion strength of 2.5 MPa on wood and has excellent sealing performance underwater. Furthermore, the adhesion strength of the adhesive to the wood did not decay significantly after 10 cycles. Benefiting from the above-mentioned adhesion and recyclability advantages, BHETA can also be developed into a high-density rigid foam with remarkable compression resistance (2.1 MPa), which does not lose its compressive strength over a long period of time. This novel recycling strategy offers a new idea for the efficient utilization of degraded products from waste PET.

Chemical recycling of polyester textile wastes using silver-doped zinc oxide nanoparticles: an economical solution for circular economy.

The waste management of polyethylene terephthalate (PET)-derived polyester (PES) textile is a global issue, and material recovery throughchemical recycling can restore a circular economy. In our investigation, microwave-induced catalytic aminolysis and glycolysis of PES textile wastes using Ag-doped ZnO nanoparticles have been proposed. Ag-doped ZnO is prepared by the sol-gel method and characterised by XRD, FT-IR, UV-Vis, SEM-EDX and TEM. The reaction parameters such as PET-to-catalyst ratio, microwave power and irradiation time, temperature and catalyst recycling have been optimised. The catalyst was found to be more stable and could be recycled up to six times without losing its activity. Both theaminolysis and glycolysis of PES showed 100% conversion and afforded of bis (2-hydroxy ethylene) terephthalamide (BHETA) and bis (2-hydroxy ethylene) terephthalate (BHET), respectively. The depolymerisation of PES wastes using Ag-doped ZnO afforded BHETA and BHET for about 95 and 90%, respectively. The monomers BHET and BHETA confirmed by FT-IR, 1H NMR and mass spectroscopy. According to the findings, 2 mol% Ag-doped ZnO has higher catalytic activity.

High-Temperature Performance Enhancement of Bitumen by Waste PET-Derived Polyurethane

Bitumen performance enhancement through modification by reactive polymers gained significant attention in the road construction industry. Polymeric bitumen additives, such as polyurethane, improve bitumen properties at low and high in-service temperatures. This research aimed to increase the polymer content (polyurethane) from 3% to 5%wt of bitumen by introducing cross-linking agent, sulfur. Synthesis of polyurethane was via in situ polymerization of bis (2-hydroxyethyl) terephthalamide (BHETA) in the presence of bitumen with sulfur as a cross-linking agent. BHETA was produced from polyethylene terephthalate (PET) by an aminolysis reaction. Penetration and softening point, frequency sweep test, performance grade (PG) and multiple stress creep recovery (MSCR) were evaluated to compare base and modified bitumen. Results show that the penetration and softening point of modified binders were reduced and increased, respectively, the frequency sweep test indicated improvement in viscoelastic properties of modified bitumen, PG of base bitumen was enhanced by two grades, i.e., from 58°C to 70°C, and the nonrecoverable creep compliance was increased by 81.82% at polymer content of 4% and sulfur content of 0.2%. The FTIR spectra of modified bitumen confirmed the formation of urethane linkages. Therefore, aminolysis of waste PET and in-situ polymerization to produce polyurethane can be applied to improve the performance of bitumen at high temperatures.

Nucleating Agents to Enhance Poly(l-Lactide) Fiber Crystallization during Industrial-Scale Melt Spinning.

The nucleating agent N,N′-bis(2-hydroxyethyl)-terephthalamide (BHET) has promising effects on poly(l-lactide) (PLA) under quiescent conditions and for injection molding applications, but its suitability for industrial-scale fiber melt spinning is unclear. We therefore determined the effects of 1% and 2% (w/w) BHET on the crystallinity, tenacity, and elongation at break of PLA fibers compared to pure PLA and PLA plus talc as a reference nucleating agent. Fibers were spun at take-up velocities of 800, 1400 and 2000 m/min and at drawing at ratios of 1.1–4.0, reaching a final winding speed of 3600 m/min. The fibers were analyzed by differential scanning calorimetry, wide-angle X-ray diffraction, gel permeation chromatography and tensile testing. Statistical analysis of variance was used to determine the combined effects of the spin-line parameters on the material properties. We found that the fiber draw ratio and take-up velocity were the most important factors affecting tenacity and elongation, but the addition of BHET reduced the mechanical performance of the fibers. The self-organizing properties of BHET were not expressed due to the rapid quenching of the fibers, leading to the formation of α′-crystals. Understanding the behavior of BHET in the PLA matrix provides information on the performance of nucleation agents during high-speed processing that will allow processing improvements in the future.

Investigation of conventional analytical methods for determining conversion of polyethylene terephthalate waste degradation via aminolysis process

There is a growing interest in the depolymerization of polyethylene terephthalate (PET) waste for both environmental and economic reasons by chemical methods. In this work, PET waste was depolymerized through aminolysis using excess amount of monoethanolamine. Bis (2-hydroxy ethylene) terephthalamide (BHETA) was obtained as the main product. For the first time, the reaction conversion was calculated, by FTIR, DSC, TGA, and CHN methods, and compared with that of measured by conventional gravimetric method. As a result, TGA and DSC are the suitable methods for calculating the reaction conversion. The gravimetric method does not measure reaction conversion, but correctly measure the yield of reaction.

Improving Processing, Crystallization, and Performance of Poly-l-lactide with an Amide-Based Organic Compound as Both Plasticizer and Nucleating Agent

In this work, we report on a novel hydrogen-bonding compound, N,N′-bis(2-hydroxyethyl)terephthalamide (BHET), and its potential as additive in poly-l-lactide (PLA). Although the hydroxyl groups of ...

Rheological evaluation of bitumen modified using antistripping additives synthesised from waste polyethylene terephthalate (PET)

ABSTRACT The use of amine-based additives is common practice to improve the stripping resistance and performance properties of bituminous mixtures. This study is concerned with the synthesis of additives derived from waste Polyethylene Terephthalate (PET), and investigation of its effect as an effective modifier for bitumen. Firstly, two amine functionalised additives namely bis(2-hydroxyethyl) terephthalamide (BHETA) and bis(2-aminoethyl) terephthalamide (BAET) were chemically synthesised using an aminolysis process from waste PET. The effects of BAET and BHETA on bitumen and bituminous mixture performance were then identified through conventional binder, Marshall Stability, Hot water stripping, Superpave performance, and Hamburg Wheel Tracking tests. The results indicated that BAET modified bitumen showed a significant improvement in moisture resistance as well as other properties such as enhanced Marshall stability, low and high temperature performance. On the other hand, BHETA modified bitumen did not show similar characteristics and exhibited only a marginal performance improvement as compared to the virgin bitumen. It was inferred from the proposed interaction mechanism that the terminal functional group of the additives has a substantial effect in determining the performance properties of such modified binders. Overall, this study has confirmed the possibility of using waste PET materials as an environmentally friendly modifier for bituminous mixtures.

Preparation and evaluation of waste PET derived polyurethane polymer modified bitumen through in situ polymerization reaction

Polymer modified bitumen (PMB) pavement have gained significant importance in the twentieth century and they now play a very crucial role in the field of road construction in every part of world. However, due to well-known difficulties related to the poor solubility of polymers, high temperature stability, sever manufacturing condition and high polymer cost restricts the use of polymer for bitumen modification. To overcome all these difficulties the present study has attempted to demonstrate a new approach where in situ polymerization of monomers bis(2-hydroxyethyl) terephthalamide (BHETA) (which is synthesized from aminolysis reaction of waste Poly Ethylene Terephthalate (PET)) with diphenylmethane-diisocyanate (MDI) in the body of bitumen for the development of polyurethane based Polymer modified bitumen (BHETA-PU). The resulting BHETA-PU product is comparable performance under laboratory condition with conventional styrene butadiene styrene (SBS) based PMB. To investigate the modifiedbitumen properties and mixture properties, conventional binder tests (Penetration, Softening Point, Marshall Stability, Hot water Stripping & short-term aging test) and Superpave binder tests (Rotational Viscosity, Dynamic Shear Rheometer (DSR), Bending Beam Rheometer (BBR) were carried out. The result reveals that BHETA-PU show significant improvement of antistripping as well as other physico-chemical properties and Marshall Stabilities. This research studies, therefore, suggests not only a new method for making PMB based on PET but also opens a new chapter for the recycling of waste PET in bitumen concrete roads which may help in easy disposal of waste PET polymer.

Deep eutectic solvent as effective catalyst for aminolysis of polyethylene terephthalate (PET) waste

Aminolytic depolymerization of poly (ethylene terephthalate) (PET) bottle waste was carried out by diethanolamine and ethanolamine using synthesized deep eutectic solvents, choline chloride.x ZnCl2 and choline chloride.2 urea, as catalyst. The reaction parameters were optimized through variation in the time of aminolysis, catalyst concentration and the PET: amine ratio. Pure products N1,N1,N4,N4-tetrakis (2-hydroxyethyl)-terephthalamide (THETA) and terephthalic acid (TPA), and bis (2-hydroxy ethylene) terephthalamide (BHETA) in yields 82, 83 and 95 % respectively, were obtained. These products were characterized by FTIR spectroscopy, 1H NMR, 13C NMR spectroscopy and differential scanning calorimetry.

From Aminolysis Product of Pet Waste to Value-Added Products of Polymer and Assistants

In this work, the aminolysis depolymerization of poly(ethylene terephthalate) PET was carried out with ethanolamine and several acetates as catalysts. The main product, bis(2-hydroxyethyl) terephthalamide (BHETA), was identified from FTIR and 1H NMR. It was found that PET depolymerization is favoured by increasing temperature, time and catalysts. Results shown that under present conditions of aminolysis, the conversion of PET was 100% and high yield of BHETA. Moreover, aminolysis products have the potential to undergo further reactions to yield secondary value-added product, such as unsaturated polyesters, polyurethanes, epoxy resin hardeners and non-ionic polymer surfactants.

Chemical conversion of PET waste using ethanolamine to bis(2-hydroxyethyl) terephthalamide (BHETA) through aminolysis and a novel plasticizer for PVC

Poly(ethylene terephthalate) (PET) recycling has been carried out by various methods, e.g., mechanical recycling, chemical recycling and energy recovery method. In this study, chemical recycling of PET was carried out by aminolysis using ethanolamine and converted into bis(2-hydroxyethyl) terephthalamide (BHETA). The reaction was performed by varying the PET:ethanolamine ratio, reaction time and catalyst used for waste medical grade bottles of PET. Yield of about 81 % was obtained for PET:ethanolamine ratio of 1:4 (w/w), with 3 h reaction time, at 160 °C with zinc acetate as a catalyst. BHETA was characterized with FTIR, 1H NMR, and DSC analysis. BHETA was further reacted with heptanoic acid at a molar ratio of 1:2.5. The product obtained was used as a plasticizer for PVC at 5, 10, 15 and 20 parts per hundred (phr) concentration. Thermal and mechanical tests were carried out and the result obtained was compared with the virgin PVC without plasticizer and with conventional plasticizer of PVC, i.e., dioctyl phthalate at 15 phr concentration since new plasticizer showed excellent properties at 15 phr concentration. This newly synthesized plasticizer was completely fused with PVC and in tensile testing helped in increasing the elongation, which was an indication of the plasticization effect shown by this developed material. Glass transition temperature also decreased with an incorporation of the new plasticizer as compared to virgin PVC.

Microwave irradiated synthesis and characterization of 1, 4-phenylene bis-oxazoline form bis-(2-hydroxyethyl) terephthalamide obtained by depolymerization of poly (ethylene terephthalate) (PET) bottle wastes

Article history: Received February 08, 2012 Received in Revised form Feb 19, 2011 Accepted 10 March 2011 Available online 31 March 2012 The aminolytic depolymerization of PET bottle waste with ethanolamine by conventional heating and microwave irradiation heating method was attempted with heterogeneous, recyclable acid catalysts such as beta zeolite (SiO2/ AlO2= 15 Naform) and montmorillonite KSF. The pure product bis-(2-hydroxyethyl) terephthalamide (BHETA) of aminolysis was obtained in good yield (8588%). The BHETA, thus obtained, was subjected to cyclization reaction by heating with polyphosphoric acid as well as by chlorination (using phosphoryl chloride), bromination (using red phosphorous and liquid bromine) and nitration (conc. HNO3 + conc. H2SO4) followed by conventional and microwave irradiation heating in N,Ndimethyl formamide/ potassium carbonate solution. The product so obtained was 2, 2’-(1,4-phenylene)– bis-(2-oxazoline) (PBO), which has applications in polymer synthesis as a chain extender/ chain coupling agent or a cross linker. The productswere analyzed by FTIR, DSC, Mass and NMR (1H and 13C NMR). © 2012 Growing Science Ltd. All rights reserved.

From Aminolysis Product of PET Waste to Novel Biodegradable Polyurethanes

Chemical recycling of PET has been developed by various methods. Aminolysis is one of chemical recycling methods of PET has been developed recently. The obtained product using aminolysis, Bis (2-hydroxy ethylene) terephthalamide (BHETA), has the potential for further reactions to obtain useful products. There are few reports on usage of recycled BHETA from PET waste to synthesis of polyurethanes. On the other hand, various biodegradable polyurethanes have been synthesized using polycaprolactone diol. Therefore, caprolactone is a new potential in synthesis of biodegradable polyurethanes from PET waste. In this work, novel biodegradable polyurethanes have been synthesized using BHETA. In this order, at first polyols with different molecular weights have been synthesized through ring opening polymerization of caprolactone by BHETA, then urethane linkages were formed using HDI (Hexamethylene Diisocyanate) without chain extender. Chemical, thermal, mechanical and dynamic mechanical properties, biodegradability, morphology and UV resistance of synthesized polyurethanes have been investigated.

Synthesis and characterization of BHETA based new polyurethanes

AbstractRecycling of polyethylene terephthalate (PET) by aminolysis breeds environmental benefits. In this work Polyethylene terephthalate in the form of waste fibers were subjected to depolymerization through aminolysis using excess amount of ethanolamine in the presence of sodium acetate, as catalyst. Obtained product, bis (2‐hydroxy ethylene) terephthalamide (BHETA) was in its pure form with sufficiently high yields. The purified product was characterized by FTIR, 1HNMR and 13CNMR spectroscopy as well as melting point determination. Since catalyst and raw materials have low price, synthesis of this material is economical and could be used as diol to synthesis of polyurethanes. In this search, polyurethanes have been synthesized based on BHETA, HDI and polyethylene glycol via prepolymer method. Termogravimetric analysis (TGA) and Differential scanning calorimetry (DSC) were carried out to study thermal stability, thermal transitions, Tm and Tg of synthesized polyurethanes. Effect of BHETA content in the main chain of synthesized polyurethanes on thermal stability of polyurethanes, strength and stiffness has been evaluated. BHETA based polyurethanes show Young's modulus about 300 MPa and elongation at break as 130% due to its aromatic structure.

Chemical recycling of poly(ethylene terephthalate) waste using ethanolamine. Sorting of the end products

There is a growing keen interest aimed at recycling post-consumer poly(ethylene terephthalate), PET, wastes for both environmental and economic reasons. In this study ethanolamine (EA) has been investigated for aminolytic degradation of PET waste in the presence of dibutyl tin oxide (DBTO) as a catalyst. The process proceeds at 190 °C and under atmospheric pressure. The yield of white precipitate was subject to spectroscopic measurements (FT-IR, NMR, XRD and MS), to thermal analyses (DSC, DTA and TG) and to chemical testing (elemental analysis and solubility characterization). Based on the data reached from various examinations, the product formed is identified as bis(2-hydroxyethylene) terephthalamide (BHETA) which could be consider a source for differing polyurethanes. These kinds of materials have potential for many applications such as adhesives and coatings.

Microwave-assisted aminolytic depolymerization of PET waste

Polyethylene terephthalate (PET) fibre waste and disposable soft drink bottle waste were subjected to depolymerization via aminolysis using excess of ethanolamine. The reaction was carried out under non conventional microwave energy in the presence of different simple chemicals as catalysts namely, sodium acetate, sodium bicarbonate and sodium sulphate. After repeated crystallization, pure bis (2-hydroxyethyl) terephthalamide (BHETA) was obtained with very high yields (nearly 90%). It was subjected to characterization by elemental analysis, melting point, FTIR, NMR and DSC. With the use of microwave energy, the process becomes economically viable since high yields of BHETA (>90%) at very low reaction time (4 min) could be obtained with common and cheap chemicals as catalysts.

Synthesis and characterization of novel polyurethanes based on aminolysis of poly(ethylene terephthalate) wastes, and evaluation of their thermal and mechanical properties

AbstractBACKGROUND: Much research is currently directed towards recycling post‐consumer poly(ethylene terephthalate) (PET) products for both environmental and economic reasons. Aminolysis of PET wastes using different amines, such as allylamine, morpholine, hydrazine and polyamines, leads to different reaction products as diamides of terephthalic acid, which do not possess any potential for further chemical reactions. In the past, the use of ethanolamine has been investigated for the aminolytic degradation of PET waste in the presence of different simple chemicals such as sodium acetate as catalysts. The product obtained, bis(2‐hydroxyethylene) terephthalamide (BHETA), has potential for further reactions to obtain useful products. Nevertheless, there has been no report on using recycled BHETA from PET to synthesize polyurethanes.RESULTS: In this research the product of aminolysis of PET waste, BHETA, was prepared. Then novel polyurethanes were synthesized based on the BHETA prepared, 1,4‐butanediol, ether‐type polyol and various molar ratios of hexamethylene diisocyanate. To evaluate the effect of BHETA, the properties of the polyurethanes without and with BHETA were compared. Fourier transform infrared spectra, thermal transitions, degradation, swelling ratio and chemical resistance of the synthesized polyurethanes were investigated. Also, the polyurethanes were applied as adhesives on various substrates. Comparison of the maximum bond strength of the synthesized polyurethane to that of commercial adhesives shows an about 2.2‐fold increase.CONCLUSION: It is possible to synthesize new polyurethanes with interesting properties using BHETA as an aminolysis product of PET waste. These kinds of materials have potential for many applications, such as adhesives and coatings. Copyright © 2008 Society of Chemical Industry

Aminolysis of polyethylene terephthalate waste

Polyethylene terephthalate in the form of waste fibres and disposable soft drink bottles was subjected to depolymerisation through aminolysis using excess of ethanolamine in the presence of different simple chemicals, namely glacial acetic acid, sodium acetate and potassium sulphate, as catalysts. The product bis(2-hydroxy ethylene)terephthalamide (BHETA) obtained was in its pure form with sufficiently high yields with all the catalysts. The purified product was characterised by elemental analysis, melting point, IR spectroscopy, Nuclear Magnetic Resonance (NMR) and Differential Scanning Calorimetry (DSC). The process of aminolysis reported here is economically viable since yields of BHETA are as high as 91%, it has potential for further reactions to obtain useful products and the chemicals used as catalysts are common and cheaply available.