PET Polymer Research Articles

Functionalized Cellulose: PET Polymer Fibers with Zeolites for Detoxification Against Nerve Agents

Presently activated carbon is used as an adsorptive material for chemical and biological warfare agents. It possess excellent surface properties such as large surface area, fire-resistance and plenty availability, but has disadvantages such as its heavy weight, low breathability (after adsorption of moisture) and disposal. In this paper, we propose to utilize novel electrospun polymeric nanostructures having zeolites as catalyst materials. In this respective, the electrospun polymer nanofibers would serve as the best possible substitutes to activated carbon based protective clothing applications. This is the first in the literature that reports the integration of these types of catalysts with nanofiberous membranes.?Electrospinning of cellulose/polyethylene terephthalate (PET) blend nanofibers has been carried out. Zeolite catalysts (Linde Type A and Mordenite) for the detoxification of nerve agent stimulant-paraoxon, were prepared due to their relative simplicity of synthesis. These catalysts were characterized using SEM and XRD analysis. The catalysts were then coated onto nanofiber membranes and their morphology was confirmed using SEM. This is the first report on the coating of nanofibers with zeolites and their successful demonstration against nerve agent stimulant. The UV studies clearly show the detoxification ability of the functionalized fibers and its potential to be used in textiles for protection and decontamination.

ZnO nanorods grown on polymer substrates as UV photodetectors

Vertical well-aligned and uniform ZnO nanorods were successfully prepared on low cost and flexible PET polymer substrate by aqueous solution method under various growth conditions. Current–voltage (I–V) and current–time (I–t) relationships measurements demonstrate that the photocurrent can be increased by more than 25 times upon UV illumination (λ=365nm) with a power density of 70μW/cm2. The photocurrents can be repeatedly and reproducibly switched by modulating UV exposure with power densities of 25–70μW/cm2. The fast response time (100s) and rapid recovery time (120s) are achieved in UV turn-on/off switching measurements. Owing to the good performance including mechanical flexibility, nondestructive properties, high reliability and multilevel photoresponse, the well-aligned ZnO nanorods grown on transparent and flexible PET polymer substrates have high potential for UV photodetector applications.

Preparation and study on the structure and properties of rare-earth luminescent fiber

In order to further explain the luminous properties of rare-earth luminescent fiber and promote various-product development of the fiber, in this research, rare-earth luminescent fiber was prepared by using rare-earth strontium aluminate as the rare-earth luminescent material, fiber-forming polymer PET as the matrix. The microstructure, composition and properties of rare-earth luminescent fiber were studied systematically based on tests and analysis with luminescent fiber, rare-earth luminescent materials and polyester fiber in detail. The results showed that the crystal structure of SrAl2O4: Eu2+, Dy3+ distributed in fiber was not destroyed by the polymer matrix and that the complex manufacturing process to ensure luminous properties of fiber performed well. Meanwhile, the structure and properties of luminescent fiber with no distinct changes were similar with that of the polyester fiber. The breaking tenacity and elongation of luminescent fiber in the wet state decreased respectively compared to the dry, and the breaking tenacity of polyester fiber was higher than luminescent fiber. The endothermic melting peak and glass transition temperature of luminescent fiber were slightly higher than that of polyester fiber. Decay curves of samples were successfully fitted by the sum of three exponential components with different decay times. Characteristic decay tended to be longer in luminescent fiber, while the initial luminance intensity of SrAl2O4: Eu2+, Dy3+ was higher than that of luminescent fiber.

Rod like attapulgite/poly(ethylene terephthalate) nanocomposites with chemical bonding between the polymer chain and the filler

Poly(ethylene terephthalate) (PET) nanocomposites containing rod-like silicate attapulgite (AT) were prepared via in situ polymerization. It is presented that PET chains identical to the matrix have been successfully grafted onto simple organically pre-modified AT nanorods (MAT) surface during the in situ polymerization process. The covalent bonding at the interface was confirmed by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The content of grafted PET polymer on the surface of MAT was about 26 wt%. This high grafting density greatly improved the dispersion of fillers, interfacial adhesion as well as the significant confinement of the segmental motion of PET, as com- pared to the nanocomposites of PET/pristine AT (PET/AT). Owing to the unique interfacial structure in PET/MAT compos- ites, their thermal and mechanical properties have been greatly improved. Compared with neat PET, the elastic modulus and the yield strength of PET/MAT were significantly improved by about 39.5 and 36.8%, respectively, by incorporating only 2 wt % MAT. Our work provides a novel route to fabricate advanced PET nanocomposites using rod-like attapulgite as fillers, which has great potential for industrial applications.

Hemocompatible Poly(ethylene terephthalate) Polymer Modified via Reactive Plasma Treatment

In this paper we present the fabrication of micro- and nanostructure poly(ethylene terephthalate) (PET) polymer surfaces used for as synthetic vascular grafts and their hemocompatible response to plasma-treated surfaces. The surface modification of PET polymer was performed using radio frequency (RF) weakly ionized and highly dissociated oxygen or nitrogen plasma. The surface of the PET polymer was modified to enable the improved proliferation of endothelial cells. In addition to biological experiments performed in vitro by assessing the number of attached cells by tetrazolium compound (MTS)-based cell proliferation assay, we also analyzed the chemical modification of plasma-treated surfaces by X-ray photoelectron spectroscopy (XPS), while the changes in morphology and surface roughness were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. Our results indicate that surface treatment with both oxygen and nitrogen plasma improved the proliferation of endothelial cells, which increased with treatment time by 15 to 30%. This phenomenon was explained by the creation of new functional groups and the modification of surface morphology, which promotes the adhesion of endothelial cells.

Hemocompatible Poly(ethylene terephthalate) Polymer Modified via Reactive Plasma Treatment

In this paper we present the fabrication of micro- and nanostructure poly(ethylene terephthalate) (PET) polymer surfaces used for as synthetic vascular grafts and their hemocompatible response to plasma-treated surfaces. The surface modification of PET polymer was performed using radio frequency (RF) weakly ionized and highly dissociated oxygen or nitrogen plasma. The surface of the PET polymer was modified to enable the improved proliferation of endothelial cells. In addition to biological experiments performed in vitro by assessing the number of attached cells by tetrazolium compound (MTS)-based cell proliferation assay, we also analyzed the chemical modification of plasma-treated surfaces by X-ray photoelectron spectroscopy (XPS), while the changes in morphology and surface roughness were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. Our results indicate that surface treatment with both oxygen and nitrogen plasma improved the proliferation of endothelial cells, which increased with treatment time by 15 to 30%. This phenomenon was explained by the creation of new functional groups and the modification of surface morphology, which promotes the adhesion of endothelial cells.

PET/PA nanocomposite blends with improved gas barrier properties: Effect of processing conditions

AbstractThe aim of this research is to develop nanocomposite polyethylene terephthalate‐polyamide blends (PET/MXD6 blends) with low oxygen permeability. Particular attention has been paid to the relation between barrier properties and the processing route adopted and therefore four different strategies were considered. Mechanical characterization shows that clay may effectively act as reinforcing filler in PET/MXD6 blends. Morphological characterization shows the strong effect of the processing strategy on clay dispersion and its distribution between the PET and polyamide phases. Barrier properties of PET/MXD6 nanocomposite blends are enhanced with respect to neat PET polymer as well as PET/MXD6 blends. The significant effect of processing techniques on barrier properties is also revealed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.

Flexural modulus identification of thin polymer sheets

The method of determination of the flexural Young's modulus is based on a solution to the problem of compression of a thin-walled cylindrical specimen by two parallel planes (TWCS method). This method was employed to calculate the flexural modulus for PET polymer compositions. The flexural modules received by TWCS method were verified by comparing the experimentally measured eigenfrequencies by Polytec vibrometer with numerical results from ANSYS program.

Preparation of polyester/reduced graphene oxide composites via in situ melt polycondensation and simultaneous thermo-reduction of graphene oxide

The introduction of graphene into a polymer matrix can markedly improve its mechanical properties and electrical conductivity. We report herein a novel strategy to fabricate polyester/reduced graphene oxide composites via simultaneous dispersion and thermo-reduction of graphene oxide (GO) during in situ melt polycondensation. The pristine graphite was first oxidized using a strong oxidant acid to prepare GO, and then GO sheets were dispersed into ethylene glycol (EG), where a homogeneous dispersion of GO in EG was obtained with ultrasonication. Finally polyester/reduced graphene oxide composites were prepared via in situpolymerization of terephthalic acid (PTA) and ethylene glycol containing well dispersed GO. Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and sedimentation experiments have been used to characterize the prepared composites. It is demonstrated that poly(ethylene terephthalate) (PET) chains may have been sucessfully grafted onto GO sheets during polymerization, accompanied by the thermo-reduction from GO to graphene. The TGA and XPS results showed that the content of grafted PET polymer was about to 60–80%, which indicates a homogeneous dispersion of GO sheets in the PET matrix, as demonstrated by SEM. Furthermore, a significant improvement in tensile strength and elongation at break of PET has been achieved. Therefore, our work provides a new way for the preparation of polyester/reduced graphene oxide composites and functionalization of graphene.

Effect of aging on the fracture mechanics of unsaturated polyester based on recycled PET polymer concrete

This research investigates, the fracture mechanics (toughness and energy), at early ages, of polymer concrete made with unsaturated polyester resin as binder. The results indicate that the fracture parameters (toughness and energy) decrease and the brittleness increases with the age of the polymer concrete.

Functionalization of a Polymer Using Nanoparticles Immobilized in Supercritical Carbon Dioxide

We demonstrated the immobilization of functional nanoparticles onto a poly(ethylene terephthalate) (PET) polymer using supercritical CO2 (SCCO2). Gold nanoparticles (AuNPs) and cadmium sulfide nanoparticles (CdSNPs) were prepared in accordance with a previously reported method. Both of the PET polymer and the nanoparticle dispersion solution were treated in SCCO2. Treatment was carried out at various temperatures and pressures. The optical properties of the treated films were observed by UV–visible (vis) absorption spectroscopy or emission spectroscopy. For the UV–vis absorption spectra of the PET films treated with AuNPs of ca. 3 nm diameter (3-AuNPs), a surface plasmon band appeared at about 550 nm, which characterized gold nanoparticles or its aggregates. For the emission spectra of the PET films treated with CdSNPs of ca. 4 nm diameter (4-CdSNPs), an emission peak appeared at about 600 nm. We found that the PET films could be functionalized using 3-AuNPs or 4-CdSNPs immobilized in SCCO2 (50 °C, 20 MPa, 2 h).

Structural and thermal properties of modified poly(ethylene terephthalate)

High-molecular-weight copolyesters based on ethylene glycol, tetraphthalic and 4,4′-biphenyl dicarboxylic acids containing up to 10.3 mole % of a second component were synthesized in the presence of homo- and heterogeneous catalysts. It was found that synthesis of these copolymers with a heterogeneous catalyst yields polymers with a higher molecular weight. The thermochemical properties of the copolyesters obtained were investigated. The thermostabilizing effect on addition of up to 10.3 mole % ethylene-4,4′-biphenyl dicarboxylic acid units to the PET polymer substrate was demonstrated. It was hypothesized that this modifier is a mesogen with respect to poly(ethylene terephthalate).

Time evolution of ion guiding through nanocapillaries in a PET polymer

We measured the time evolution of the guided transmission of 3keV Ne7+ ions through nanocapillaries in insulating PET polymers. Capillaries with a diameter of 200nm and a density of 4×106cm−2 were used. The angular distribution of the transmitted ions was measured as a function of the charge deposited on the sample surface, which is a measure of time. The evolution of the angular transmission profiles was acquired for different tilt angles ranging from 0° to 5°. The transmission profiles appear as a superposition of essentially 3 localized peaks which exhibit significant changes in intensity as time varies. This observation provides evidence for the formation of temporary charge patches produced in the interior of the capillary besides the primary charge patch created in the entrance region.

Design of an oval-form cathode for the precision etching process of e-paper surface

A newly designed oval-form cathode using electroetching for indium–tin-oxide (ITO) microstructure removal from the surface of e-paper polymer PET films is presented. Through ultra-precise microstructural etching, the semiconductor industry can effectively reclaim defective products, thereby reducing production costs. The design features for the ITO removal process and the tool design of oval-form cathodes are of significant interest. A smaller oval-form cathode minor axis, a higher cathode rotational speed, a higher concentration, or a higher electrolyte temperature corresponds to a higher ITO etching rate.

In situ microwave‐assisted polymerization of polyethylene terephtalate in layered double hydroxides

AbstractThe synthesis of poly(ethylene terephthalate) (PET)/layered double hydroxide (LDH) nanocomposites through microwave methods has been investigated. To enhance the compatibility between the PET polymer and the LDH, dodecyl sulfate was intercalated in the lamellar structure. The organo‐LDH structure was confirmed by powder X‐ray diffraction (PXRD) and Fourier transform infrared spectroscopy (FTIR). PET nanocomposites were prepared with 0–10 wt % of LDH content by in situ microwave‐assisted polymerization. PXRD was used to detect the formation of the exfoliated PET/LDH nanocomposites. Transmission electron microscopy was used to observe the dispersed layers and to confirm the exfoliation process. FTIR spectroscopy confirmed that the polymerization process had occurred. TG and DTA are used to study changes in thermal stability of the nanocomposites, which resulted enhanced by well dispersed LDHs layers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Residual strain recovery, molecular mobility, and plasticity of solid aromatic copolyesters of p-hydroxybenzoic acid with poly(ethylene terephthalate)

The processes of thermally stimulated recovery of internal energy stored by a specimen during deformation and of residual strain ɛres in weakly oriented liquid-crystalline 80: 20 and 60: 40 (by mole) copolyesters of p-hydroxybenzoic acid with PET, as well as in nonoriented (amorphous and crystalline) PET, were studied. All the materials were deformed via uniaxial compression at room temperature. It was shown that ɛres is built up in all phases that coexist in the materials: the glassy, crystalline, and intermediate phases, of which the last presumably contains imperfect crystals of a small size. Excess energy of strain is stored in the glassy phase with a built-in LC order and, probably, in copolyester crystallites. The main deformation processes in the glassy component of the materials are the nucleation and development of small-scale shear transformations in exactly the same manner as in the earlier studied glassy polymers that do not form an LC structure. Consequently, enhanced rigidity of the polyesters chains and their LC order have no qualitative effect on the mechanism of plastic deformation of the copolyester glasses. However, the LC structure leads to a decrease in the yield stress σy and the compression and shear moduli of the copolyesters in comparison with those of conventional glassy polymers i.e., reduces the resistance of the materials toward plastic deformation. With an increase in strain, various forms of Brownian motion of chains, beginning from the rotation of p-hydroxybenzoic acid fragments, become successively involved in the process of their deformation at room temperature. Correspondingly, the thermally stimulated recovery of ɛres exhibits peaks of small-scale motions of aromatic chain fragments in the glassy phase of copolyesters, a phenomenon that is not observed in PET and other aliphatic polymer glasses. The intensity of these peaks depends on the value of ɛres built up by the specimen. Even small strains (≈5−40%) in the specimens irreversibly destroy the initial orientation of chains in copolyesters. To explain this effect, the concept of domain disorientation of their structure is proposed.

Mechanical characterization of melt spun fibers from recycled and virgin PET blends

In this study two Poly (Ethylene Terephthalate) (PET) polymers obtained from mineral water bottles and a virgin fiber grade PET polymer were investigated. In order to improve their properties when reprocessed at high temperatures, recycled polymers were blended with virgin one. Thermal and rheological properties of extruded recycled/virgin (PET-V/R) blends showed a good microstructural stability compared to extruded pure recycled polymers. Mechanical behaviour of melt spun fibers obtained from recycled/virgin blends were investigated in static (tensile) and dynamic (DMA) modes and gave interesting properties. Fatigue failure of fibers was also studied and resulting fracture morphologies were analysed by Scanning Electron microscopy (SEM).

Radiation‐induced graft copolymerization of acrylic acid/acrylonitrile onto LDPE and PET films and its biodegradability

AbstractGraft copolymerization of acrylic acid/acrylonitrile (AAc/AN) comonomer onto low‐density poly(ethylene) (LDPE) and poly(ethylene terephthalate) (PET) films using direct radiation grafting technique has been investigated. The effect of different reaction conditions on the grafting yield was studied. The structure of the grafted films at different compositions was characterized by FTIR, TGA, SEM, and XRD. Biodegradation of grafted LDPE and PET was investigated by burial method in two types of Egyptian soils (agricultural and desert soils). The bacteria responsible for biodegradation were isolated and characterized, and the capacities for the growth on these polymers as substrates were compared. The isolates from agricultural soil were characterized as Pseudomonas, Alcaligenes, Bacillus, Proteus, and Enterobacter, whereas the isolates from desert soil were characterized as Alcaligenes, Bacillus, and Pseudomonas. The highest degradation rate was found to be achieved using agricultural soil. It is found that the isolated strains belonging to the genus Pseudomonas were mainly responsible for the degradation of both polymers. It has also been found that the increase of AAc ratio in the composition increases the hydrophilicity of the films and the degradation rate. PET polymer is generally found to be more resistant to the biodegradation than LDPE in the two types of soils tested. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

The study of PET recyclable polymers as paper coatings

Two PET recyclable polymers, EvCote ® PGLR-30 and EvCote ® PWRH-30, at four ratios (0, 5, 10, 15 wt%) were studied as components of paper basecoats. The results showed that 5% of the PET recyclable polymer was the optimum ratio with regard to properties of the coated paper, particularly MVTR (moisture vapor transmission rate) and Cobb. Both of the PET recyclable polymers were evaluated as a paper topcoat as well. The results showed that both of the PET polymers as topcoats could provide excellent MVTR and Cobb properties, particularly combining with the optimized PET polymer used in the basecoat. It was also found that when the PET polymer was used as the topcoat, the effect of clay/latex ratio in the basecoat was important: more clay gave better MVTR and repulpability.

Electric properties and surface characterization of transparent Al-doped ZnO thin films prepared by pulsed laser deposition

We grew 2 wt.% Al-doped ZnO (AZO) films on 5.08 cm-diameter polymer substrates at room temperature by the pulsed laser deposition (PLD) technique added the beam-rastering function. The structural properties, surface morphology, resistivity, mobility and chemical bonding states of AZO/polymer films were measured. The structuring of polymer surface by atmospheric plasma can occur at nm scales and can influence adhesion, optical and wettability properties of the materials. With increasing plasma treatment power, surface hydrophilicity and roughness for PET and PES polymer increased, respectively.