Neat Polyethylene Terephthalate Research Articles

Scalable Dual In Situ Synthesis of Polyester Nanocomposites for High-Energy Storage.

Incorporating ultralow loading of nanoparticles into polymers has realized increases in dielectric constant and breakdown strength for excellent energy storage. However, there are still a series of tough issues to be dealt with, such as organic solvent uses, which face enormous challenges in scalable preparation. Here, a new strategy of dual in situ synthesis is proposed, namely polymerization of polyethylene terephthalate (PET) synchronizes with growth of calcium borate nanoparticles, making polyester nanocomposites from monomers directly. Importantly, this route is free of organic solvents and surface modification of nanoparticles, which is readily accessible to scalable synthesis of polyester nanocomposites. Meanwhile, uniform dispersion of as ultralow as 0.1 wt% nanoparticles and intense bonding at interfaces have been observed. Furthermore, the PET-based nanocomposite displays obvious increases in both dielectric constant and breakdown strength as compared to the neat PET. Its maximum discharged energy density reaches 15 J cm-3 at 690 MV m-1 and power density attains 218 MW cm-3 under 150 Ω resistance at 300 MV m-1, which is far superior to the current dielectric polymers that can be produced at large scales. This work presents a scalable, safe, low-cost, and environment-friendly route toward polymer nanocomposites with superior capacitive performance.

Study on the synergistic flame-retardancy of phenyl/vinyl siliconesquioxane and aluminum diethyl phosphinate on polyethylene terephthalate

Polyethylene terephthalate (PET), a widely used engineering thermoplastics, is inherently flammable, presenting significant fire risks. Aluminum diethyl phosphinate (ADP) is widely used in PET, while they tend to increase smoke hazards in its flames retardancy. A novel flame-retardant ladder phenyl/vinyl polysilsesquioxane (VPPSQ) acting as both a charring flame retardant and smoke suppressant was introduced into the PET/ADP composites. For PET/ADP6/VPPSQ4, the limiting oxygen index increased to 32.8 % from 23.3 %, and the amount of heat and smoke released was significantly reduced, compared with neat PET. Additionally, the hazard of dripping was eliminated and the UL 94 rating reaches to V-0 level. This work provides a new strategy for eliminating multiple fire hazards of smoke, heat and dripping of PET. The gas phase flame retardancy effect of ADP is primarily present during the initial stages of combustion, with the carbonization action of ADP becoming more crucial during the middle and later stages of burning. However, the char layer formed by PET/ADP is unstable and undergoes further degradation. When VPPSQ is introduced into PET/ADP, the pyrolysis products of VPPSQ, including silicon fragments, SiO2, and graphitized structures, significantly enhance the thermal stability and barrier effect of the char layer.

Surface decoration of polyethylene terephthalate (PET) waste bottle-derived ultrafiltration membrane for enhanced lead ion removal and antifouling properties

PET waste bottle can be potentially used to create eco-friendly ultrafiltration (UF) membranes for water and wastewater treatment. The surface modification and functionalization of PET UF membrane offer opportunities to further heighten the performance of the membrane. In this study, phase inversion technique was used to fabricate PET UF membranes and PET/graphene oxide (GO) nanocomposite membranes through a facile GO suspension coating approach. The GO nanosheets were deposited on the PET UF membrane as a wavy and wrinkly layer. Using lead (Pb) ions and bovine serum albumin (BSA) feed solutions, the filtration performances of the neat PET and GO-PET membranes were evaluated. It was observed that, the Pb ions and BSA removal efficiencies were greatly enhanced by the surface decorated GO. Compared to neat PET, the 0.5GO-PET membrane exhibited improved flux performance by 188% and 61% for the removal of Pb ions and BSA, respectively. A high Pb ion removal of 100% and a BSA rejection of 97% were achieved by 0.5GO-PET membrane. The lower fouling tendency of 0.5GO-PET membrane during long-term filtration was attributed to the increased surface hydrophilicity and smoothness upon the deposition of GO layer. This study demonstrates a sustainable solution for efficient water treatment and heavy metal removal.

Polyethylene Terephthalate Composite Films with Enhanced Flame Retardancy and Gas Barrier Properties via Self-Assembly Nanocoating.

The flammability and gas barrier properties are essential for package material. Herein, a highly-oriented self-assembly nanocoating composed of polyvinyl alcohol (PVA) and montmorillonite (MMT) was prepared for endowing polyethylene terephthalate (PET) films with excellent flame retardancy and gas barrier properties. The specific regular nanosheet structure of the PVA/MMT composite nanocoating was confirmed by Fourier transform infrared (FTIR) and X-ray diffraction (XRD). Thermogravimetric analysis (TGA) and the vertical burning test (VBT) suggested that the thermal stability and flame-retardancy of the coated PET films were considerably improved with more pick-up of the resulting nanocoating. When reaching 650 °C, there was still 22.6% char residual left for coated PET film, while only 6% char residual left for pristine PET film. During the vertical burning test, the flame did not spread through the whole PET film with the protection of PVA/MMT nanocoating, and no afterflame was observed. Scanning electron microscopy (SEM) is consistent with vertical burning test, proving that the thermal stability and flame retardancy of coated PET films were considerably enhanced with the increment of PVA/MMT. Thanks to the multi-layer structure, PVA/MMT nanocoating could effectively improve the gas barrier properties of PET films, and the oxygen vapor transmittance rate and water vapor transmittance rate of PET films were more than four hundred times lower and 30% lower than those of neat PET film. Our work demonstrates that bi-functional flame retardant and gas barrier materials could be gained via constructing inorganic/organic highly-oriented self-assembly nanocoating, which is promising in the area of packaging.

Thermal Degradation and Carbonization Mechanism of Fe-Based Metal-Organic Frameworks onto Flame-Retardant Polyethylene Terephthalate.

Currently, the metal-organic framework (MOF) is a promising candidate for flame-retardant polymers. In this study, a Fe-based MOF, MIL-88B(Fe), was introduced to polyethylene terephthalate (PET) and 3-hydroxyphenylphosphinyl-propanoic acid copolymer (P-PET) to reduce the fire hazard involved in using PET. The limiting oxygen indexes (LOIs) of MIL-PET and MIL-P-PET improved by 27% and 30%, respectively. The UL-94 level achieved for MIL-P-PET was V-0 rating. The thermal degradation and carbonization mechanisms of MIL-PET and MIL-P-PET were systematically investigated through thermogravimetric analysis coupled with a Fourier transform infrared spectroscopy (TG-IR), pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS), x-ray photoelectron spectroscopy (XPS), and Raman spectrum combined with quantum chemical molecular dynamics simulation. With the addition of MIL-88B(Fe), high graphitization and a hard flammability char residual were generated. Compared with neat PET, the ferric ions efficiently catalyzed the homolytic cleavage and dehydrogenation of PET to produce a large amount of CO2 and terephthalic acid for MIL-PET in gas phase. Rough and hierarchical char residual with ferric oxide was also generated when temperatures exceeded 600 °C. However, the carbonization process was inhibited due to the coordinated complex between phosphorus and ferric ions in MIL-P-PET, invaliding the decarboxylation and generating more benzoic acid and its precursor, which led to heavy smoke.

Investigating the Thermo-Oxidative Degradation and Operational Limits for Hybrid AlOX–PET Fabrics Created Via Vapor Phase Infiltration (VPI)

In vapor phase infiltration (VPI), vapor phase metalorganic precursors are diffused into polymers and further reacted with water vapor to form hybrid organic-inorganic materials. Hybrid materials created through VPI have shown utility in industrially relevant applications including membranes for chemical separation, photovoltaics, and catalysis. VPI can be conducted at different temperatures, with each processing temperature resulting in different chemical states that alter the properties of the hybrid material. In this project, polyethylene terephthalate (PET) fabrics are infiltrated with a trimethylaluminum (TMA) precursor and co-reacted with water vapor at a range of infiltration temperatures (60-140 ˚C) to create hybrid AlOX - PET fabrics. The purpose of this project is to develop a set of thermal operational limits for these hybrid organic-inorganic materials and translate techniques for thermal characterization from the textile community to the VPI community. Thermo-oxidative degradation for the hybrid fabrics was quantified through changes in degradation temperature and activation energies. Thermogravimetric analysis (TGA) was employed to quantify inorganic loadings (~20 weight percent inorganic), degradation temperatures, and the activation energy for degradation using the Flynn/Wall/Ozawa (FWO) method for decomposition kinetics. Most hybrid fabrics demonstrated lower degradation temperatures than neat PET, except for the fabric infiltrated at 140˚C which had increased degradation temperatures. Activation energies for the first thermal-oxidative degradation event for the 80˚C, 100˚C, and 140˚C fabrics decreased by a range of 62˚C to 84˚C compared to neat PET, while the 120˚C fabric’s activation energy slightly increased by 10˚C. Additionally, a new degradation event occurred for fabrics infiltrated at low temperatures which was explored through FTIR characterization and attributed to structural rearrangements of the inorganic component. Overall, this work demonstrates how VPI process conditions alter both the organic-to-inorganic chemical binding as well as the inorganic cluster structure in these hybrids and how these structural features affect thermophysical operational limits of the material.

Effects of magnesium borate on the mechanical performance, thermal and chemical degradation of polyethylene terephthalate packaging material

This study is on polyethylene terephthalate (PET) compounded with magnesium borate (MB) (Mg2B2O5) powders between (0.2–3.2% by weight) which were synthesized via sol-gel technique at laboratory-scale. The MB/PET composites were characterized in terms of chemical, thermal degradation, and mechanical properties. Their phases and chemical structures were identified by X-ray Diffraction and Fourier Transform Infrared analyses. The MB added into PET matrix significantly reduced PET degrading to acetaldehyde, carboxylic acids and diethylene glycol. However, while at 0.2 wt.% MB isophthalic acid (IPA) decreased and at higher MB concentrations there were higher IPA levels. The added MB increased the composites intrinsic viscosity (IV) compared to the pure PET. The highest IV (0.701 dL/g) was at the 0.2 wt.% MB/PET composite. Both Tg and Tm temperatures trended down up to 3.2 wt.% MB. Compared to pure PET, glass transition temperature (Tg) decreased to 80.4°C (at 3.2 wt.% MB) from 81°C, whereas melt temperature (Tm) decreased to 248.5°C (at 3.2 wt.% MB) from 249.4°C. The MB/PET composite tensile strength increased by 11.31% to a 60 MPa maximum at 0.2 wt.% MB compared to neat PET (53.9 MPa). However, at 0.4 wt. % and higher MB the dispersion was insufficient causing the MB powders to aggregate in the PET matrix, resulting in reduced tensile strength.

Interface and interphase of nanocomposites tailored by covalent grafting of carbon nanotube: Hierarchical multiscale modeling

Covalent grafting between carbon nanotubes (CNTs) and a polymer matrix is the most efficient way to tailor the intrinsically weak interface in nanocomposites. To understand the grafted structure-to-improved property relationship of nanocomposites, however, the degradation of grafted CNT and the properties of surrounding interphase zone should be accounted for in constitutive model. In this study, the reciprocity of the interface, interphase, and elasticity of CNTs depending on the covalent grafting between the CNT and a polyethylene terephthalate (PET) matrix were studied through molecular dynamics simulations and a mean-field micromechanical interface/interphase model. The replacement stiffness method was used to determine the effect of the tailored interface on the overall elasticity of a nanocomposite in micromechanics. The elasticity of the CNTs and the nanocomposites was determined from molecular mechanics and molecular dynamics simulations, respectively. Despite the degraded elasticity of the nanotubes, clear improvements in the transverse modulus and shear moduli were observed in the covalently grafted nanocomposites. The elasticity of the interphase was determined in terms of the number of covalent grafting and the interfacial compliance using a two-step inverse micromechanical analysis. Regardless of the number of covalent grafting addressed, the elastic moduli of the interphase were always larger than those of a neat PET matrix. Furthermore, the accuracy of the proposed multiscale micromechanical interface/interphase model at various volume fractions of CNTs was validated.

Improvement of Mechanical and Thermal Properties of Polyethylene Terephthalate (PET) Composite Reinforced with Chemically Treated Ladies Finger Natural Fiber

ABSTRACT In the present work, ladies finger (LF) fiber has been utilized as reinforcement in thermoplastic polymer, polyethylene terephthalate (PET). The extracted fibers were chemically treated, and the effect of chemical treatment of fibers on mechanical and thermal properties of composites was investigated and discussed. For this purpose, the fibers were treated with chemicals like sodium hydroxide at various concentrations (2%, 3%, 4%, and 5%). Then, the chemically treated fibers with varying weight percentage (0, 10, 20, 30, and 40 wt%) were reinforced in PET to develop new composites, and its various properties like mechanical properties, thermogravimetric analysis, Fourier transform infrared spectroscopy, and X-ray diffraction were thoroughly investigated and compared with untreated fiber composites and neat PET. It has been observed that the composites fabricated with treated LF fibers reveal improved properties as compared to composites containing untreated fibers. Moreover, a better fiber–matrix bonding is also observed in scanning electron microscopy images. Twentywt% of fiber loading reveals highest mechanical properties as compared to other fabricated composites and can be suitable for packaging applications.

Diamine vapor treatment of viscoelastic graphene oxide liquid crystal for gas barrier coating

A layered graphene oxide/ethylenediamine (GO/EDA) composite film was developed by exposing aqueous GO liquid crystal (GOLC) coating to EDA vapor and its effects on the gas barrier performance of GO film were systematically investigated. When a GO/EDA coating with a thickness of approximately 1 μm was applied to a neat polyethylene terephthalate (PET) film, the resultant film was highly impermeable to gas molecules, particularly reducing the gas permeance up to 99.6% for He and 98.5% for H2 in comparison to the neat PET film. The gas barrier properties can be attributed to the long diffusion length through stacked GO nanosheets. The EDA can crosslink oxygen-containing groups of GO, enhancing the mechanical properties of the GO/EDA coating with hardness and elastic modulus values up to 1.14 and 28.7 GPa, respectively. By the synergistic effect of the viscoelastic properties of GOLC and the volatility of EDA, this coating method can be applied to complex geometries and EDA intercalation can be spontaneously achieved through the scaffold of the GOLC.

Characteristics of cellulose fibers from Opuntia ficus indica cladodes and its use as reinforcement for PET based composites

ABSTRACT With the aim of valorizing the unexplored Moroccan resources, Opuntia ficus indica (OFI) cladodes were proposed as a renewable source for the production of cellulose. In this work, cellulose microfibers were extracted from OFI cladodes using one of the most suitable methods for the extraction of cellulose based on the alkaline delignification. The morphological (SEM), thermal (TGA/DTG), and structural (XRD, FTIR, and 13C NMR) analysis of the isolated cellulose has been identified. Afterward, the reinforcing capability of cellulose fibers was examined using polyethylene terephthalate (PET) as a matrix by combining extrusion and compression molding processes. The effects of fibers loading on physical properties of the composites, such as tensile strength and Young’s Modulus before and after water absorption, were studied. The stability of the optimal composite was also examined based on the dependence of rheological parameters (G’ and G”) with strain and time. Composites containing 15 wt% of fibers exhibited the best mechanical properties in dry and wet cases, reaching 88% increase from neat PET in Young’s modulus and 36% increase in the tensile strength. However, excellent structural stability of the optimal composite was found with a predominant elastic behavior resulting from the good interface adhesion between cellulose fibers and PET matrix. The present work showed new routes for the valorization of OFI cladodes in the development of composite materials.

Poly(maleic acid-co-acrylic acid) ionomer as nucleating agent on the crystallization behavior and properties of poly(ethylene terephthalate)

Polyethylene terephthalate (PET) generally suffers from low crystallization rate and long molding cycle, which limits its application in injection molding of engineering plastics. To overcome the specific shortcoming, polymaleic acid-co-acrylic acid (PMA-AA) ionomer used as a nucleating agent was added to PET by melt blending, and its effect on the crystallization behavior of PET was investigated in this paper. It is indicated that the modified PET samples (MPET) with the addition of nucleating agents exhibit much higher molecular order and faster crystallization rate. The nucleation mechanism of MPET induced by PMA-AA ionomer was analyzed by means of Avrami equation and Hoffman–Lauritzen theory, revealing that the addition of PMA-AA ionomer provides more nucleation sites and reduces the fold surface free energy of PET. The nucleation and dispersion behavior of PMA-AA ionomer were further observed by SEM and POM morphologies. The results demonstrated that ionomer was dispersed homogeneously in the PET matrix, thus leading to faster crystallization rate of MPET than neat PET. In addition, the thermal stability, mechanical properties, and gas barrier of PET and MPET were characterized.

Combustion forming hollow nanospheres as a ceramic fortress for flame-retardant fiber

Simple, effective and safe flame retardants are required to improve flame retardant properties of polymer fibers. However, traditional additive flame retardants, such as halogen-flame retardants and intumescent flame retardants, are likely to cause phase separation of functional phases due to their poor dispersibility and compatibility, or are difficult to be suitable for the high temperature processing conditions of melt-spun fibers. Here, in an effort to develop a practical flame retardant system in which zinc diphosphinate (DEPZn) and D-glucose (DG) were selectively incorporated into polyethylene terephthalate (PET) fiber was developed. As a result, the dense nano-scale zinc phosphate microspheres were formed on the surface and inside the residual carbon during combustion. Thus, PET fibers were endowed with excellent flame retardancy through a thermal barrier and enhancement of physical strength for the carbon layer. Moreover, a synergistic flame-retardant effect was found between DEPZn and DG. DG reduced the size of the zinc phosphate nanosphere from 200 ​nm to 50 ​nm, making the carbon layer denser and smoother. As a result, the peak heat release of the resultant PET composite fiber decreased to 410 ​kW/m2 compared 1276 ​kW/m2 for neat PET fiber. Moreover, the total smoke release also dropped from 71 ​MJ/kg of neat PET fiber to 64 ​MJ/kg for PET composite fibers. These results provide a promising strategy for the production of industrialized PET flame retardant fibers.

Oxygen Gas and UV Barrier Properties of Nano-ZnO-Coated PET and PHBHHx Materials Fabricated by Ultrasonic Spray-Coating Technique.

Ultrasonic spray-coating (USSC)—a wet chemical deposition method to deposit ultrathin (down to 20 nm) coatings—is being applied as a promising alternative deposition method for functional coatings due to an economical, simple, and precise coating process with easy control over its operating parameters. In this research, zinc oxide nanoparticles (ZnO NPs) were ultrasonically spray-coated on commercial-grade polyethylene terephthalate (PET) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) films. The most suitable parameters for the ink composition, the ultrasonic spray-coating process, and the number of coating passes (up to 50×) were selected on the basis of a series of experiments. The oxygen gas barrier properties in terms of the oxygen transmission rate (OTR) of neat PET, and 3×, 5×, 10×, and 50× ZnO NP-coated PET and PHBHHx substrates were investigated. The OTR values for neat PET, and 3×, 5×, and 10× ZnO NP-coated PET substrates were found to be the same; however, a 5% reduction in OTR for 50× ZnO NP-coated PET substrate was observed compared to the neat PET substrate. No reduction in OTR was found for any above number of coating passes on PHBHHx substrates against the neat PHBHHx substrate. However, the ultraviolet (UV) tests of 3×, 5×, and 10× ZnO NP-coated PET and PHBHH× substrates revealed a significant decrease in percentage transmission for 10× coated PET and PHBHHx substrates as compared to their 3× and 5× ZnO NP-coated substrates, respectively. It was revealed from the study that the 50× ZnO NP coating of the PET substrate created a slight difference in OTR as compared to the reference substrate. However, the ultrasonic spray-coating method created a significant UV barrier effect for 3×, 5×, and 10× ZnO NP-coated PET and PHBHHx substrates, which demonstrates that the optimized coating method cannot be used to create a high oxygen barrier but can certainly be applied for UV barrier applications in food packaging. It is concluded that ultrasonic spray deposition of ZnO NPs on PET and PHBHHx materials has shown promising results for UV barrier properties, demonstrating the advantages of using this method compared to other coating methods with regard to cost-effectiveness, precise coating, and better process control.

Barrier and structural properties of polyethylene terephthalate film coated with poly(acrylic acid)/montmorillonite nanocomposites

Food packaging is one of the most important parts of the food industry, and polyethylene‐based polymers have been widely used as food packaging films. In this study, corona‐treated polyethylene terephthalate (PET) films were used to increase adhesion to the barrier coating solution for multilayered film formation and various concentrations of montmorillonite (MMT; 0, 1, 3, and 5 wt.%) were used to improve the barrier properties of PET films for food packaging after different treatments of MMT including ultrasonication with bath or probe and 100‐W or 300‐W microwave to evenly disperse MMT. Among them, a 300‐W microwave treatment was most effective for size reduction of MMT particles. Even though 5 wt.% MMT was used to coat PET films with polyacrylic acid (PAA), good transmittance in the visible region (500 nm) was obtained, with a value similar to that of the neat PET film. The dispersion of MMT and binding of PAA/MMT nanocomposites were confirmed by field‐emission scanning electron microscopy, X‐ray diffraction, and Fourier transform infrared spectroscopy analyses. The water vapor and oxygen barrier properties of PET films were enhanced by PAA coating. Moreover, the oxygen permeability of PET films decreased via coating by PAA blended with 1 and 3 wt.% MMT. Based on these results, the PET film coated with PAA/MMT nanocomposites could be applied as food packaging films that require high gas barrier properties for oxygen‐sensitive food.

Rubber toughened recycled polyethylene terephthalate for material extrusion additive manufacturing

AbstractPlastic packaging materials represent a new class of low‐cost and sustainable additive manufacturing feedstocks. Recycled polyethylene terephthalate (PET) has been shown to be a robust material for material extrusion additive manufacturing, with mechanical properties comparable with acrylonitrile‐butadiene‐styrene. However, due to PET's high crystallinity, it is generally a brittle material and can be subject to premature fracture. It is well known that the addition of rubbers can serve to toughen PET. In this work, micronized rubber powder, as well as non‐reactive and functionalized styrene‐ethylene‐butadiene‐styrene (SEBS) elastomers were compounded with recycled PET. Tensile strength was not significantly affected, but toughness increased 85% with the addition of 5 wt% rubber, 350% with SEBS and over 550% with maleic anhydride functionalized SEBS compared to neat recycled PET. Fracture surface analysis revealed evidence of ductile fracture and cavitation in the rubber toughened samples. Published 2020. This article is a U.S. Government work and is in the public domain in the USA

An Experimental Study of Physical, Mechanical and Morphological Properties of Alkali Treated Moringa/areca Based Natural Fiber Hybrid Composites

ABSTRACT In this study, polyethylene terephthalate (PET) composites reinforced with areca sheath and Moringa oleifera fruit fibers were fabricated using injection molding technique. The fabricated composites were designated as Areca sheath fiber/PET (AF composites), Moringa oleifera fruit fibers/PET (MF composites) and Areca/Moringa PET composites (AM composites). Neat PET composites were also prepared for comparison purpose. Physical characteristics such as void percentage, micro-hardness and mechanical characteristics like impact, flexural and tensile strength were investigated. Scanning electron microscope (SEM) was done to get a clear idea about the surface texture and study the failure mechanism of the composites. In addition, thermogravimetric analysis (TGA) was also carried out to study the thermal properties of the composites. Experimental results indicated that tensile and flexural properties of MF composites were higher than that of AF and AM composites. However, micro-hardness and impact strength of AM composites were better than that of others. SEM micrographs presented better fiber-matrix bonding in MF composites and this indicated improved resistance of the composite to thermal degradation in TGA analysis. Thus, Moringa oleifera and areca fiber-reinforced PET composites can be used for light to moderately loaded structural engineering applications as an alternative material.

Effect of Pre-Treatment on the Morphology and Chemical Properties of Polyethylene Terephthalate (PET)/Pineapple Leaf Fiber (PALF) Electrospun Mat

In the past decades, conventional petroleum-based plastics have resulted in environmental and sustainability issues. Thus, there has been significant interest in the utilization of natural materials for nanofibers product such as for filtration media. However, poor compatibility exists between polymers and natural fibers due to natural fibers hydrophilic properties leading to poor nanofibers formation. In this study, Pineapple Leaf Fiber (PALF) remarkable properties were explored. PALF undergo alkaline treatment and bleaching treatment in order to improve its compatibility. Thermal, morphology and structural properties of PALF raw (PR), PALF after alkali treatments (PA) and PALF after alkali + bleaching treatment (PB) were studied. Further, all the samples were diluted using Trifluoroacetic Acid (TFA) as the solvent and Polyethylene Terephthalate (PET) as the polymer carrier and proceed to electrospinning to produce a nanofibers electrospun mats. The electrospun mats were then characterized in terms of its chemical properties using Fourier transform infrared spectroscopy (FTIR) as well as the morphology which using Fields Emission Scanning Electron Microscopy (FESEM). FTIR result shows the electrospun PET does not produce any peak at ~3400cm-1 due to its hydrophobic properties. Nevertheless, with addition of PALF, the peak was significantly increased. FESEM results indicated that the present of fibers led to a tendency of lower average fiber diameter compared to the neat PET. Unconnected and thin fibers were coexited from single fiber of PALF raw electrospun indicated that new fibers were ejected however the bond were collapsed during ejection thus did not produce a complete single fiber. Despite that, more uniform fibers of electrospun mat were produced by pre-treatment of PALF.

Recycled polypropylene blends as novel 3D printing materials

Consumer-grade plastics can be considered a low-cost and sustainable feedstock for fused filament fabrication (FFF) additive manufacturing processes. Such materials are excellent candidates for distributed manufacturing, in which parts are printed from local materials at the point of need. Most plastic waste streams contain a mixture of polymers, such as water bottles and caps comprised of polyethylene terephthalate (PET) and polypropylene (PP), and complete separation is rarely implemented. In this work, blends of waste PET, PP and polystyrene (PS) were processed into filaments for 3D printing. The effect of blend composition and styrene ethylene butylene styrene (SEBS) compatibilizer on the resulting mechanical and thermal properties were probed. Recycled PET had the highest tensile strength at 35 ± 8 MPa. Blends of PP/PET compatibilized with SEBS and maleic anhydride functionalized SEBS had tensile strengths of 23 ± 1 MPa and 24 ± 1 MPa, respectively. The non-compatibilized PP/PS blend had a tensile strength of 22 ± 1 MPa. PP/PS blends exhibited reduced tensile strength to ca. 19 ± 1–3 MPa with the addition of SEBS. Elongation to failure was generally improved for the blended materials compared to neat recycled PET and PS. The glass transition was shifted to higher temperatures for all of the blends except the 50–50 wt. % PP/PET blend. Crystallinity was decreased for the blends, but was highest in the 75–25 wt. % PP/PS and the 50-50 wt. % PP/PET blend with SEBS-maleic anhydride. Solvent extraction of the dispersed phase revealed polypropylene was the matrix phase in both the 50–50 wt. % PP/PET and PP/PS blends.

Morphology and Crystallization of Biobased Polyamide 56 Blended with Polyethylene Terephthalate

AbstractThis study attempts to promote biobased polyamide 56 (PA56) as a sustainable candidate to replace commercial PA6 and PA66 when blended with polyethylene terephthalate (PET). Scanning and transmission electron microscopy of the blends with different PA56 contents reveals an immiscible morphology with an increase in the size of the dispersed domains by increasing PA56 content. The steady‐state mixing torque of the kneader is decreased to half by adding 10 wt% of PA56 to PET. Further addition of PA56 gradually increases this torque but does not surpass the neat PET sample up to 30 wt% of PA56. As revealed by microscopic dissipative particle dynamics (DPD) simulations, this gradual increase is ascribed to the difficulty to disperse larger domains of PA56 in the thermodynamically undesired PET. The results confirm that PA56 has a lubricating effect in PET. Using polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X‐ray diffraction (XRD) techniques, it is shown that PA56 acts as a nucleating agent in PET. This leads to the formation of numerous small crystals in the blends as opposed to several large crystals in the neat samples. The results encourage the use of PA56 biomaterial in combination with PET in products such as bicomponent segmented pie fibers.