PET Blends Research Articles

A discovery for phosphorus valence and unsaturated bonds in polyphosphate/polyphosphonate: Promotion or inhibition for its flame-retardant mode of action in PET

Four polyphosphate/polyphosphonate flame retardants (PAP, POP, PAP-UB and POP-UB) have been designed and synthesized to study the effects of phosphorus valence states and the presence of unsaturated carbon-carbon double bonds on self-cross-linking impacting flame-retardant modes of action. It was found that phosphorus valence states affect the proportion of flame-retardant activity between the gas phase and condensed phase. A phosphonate containing +3-valence phosphorus is primarily effective as a gas-phase flame-retardant, while the one containing +5-valence phosphorus mainly exerted an impact in the condensed phase. The introduction of an unsaturated bond enhances the carbon-forming effect promoted by polyphosphates/polyphosphonates in a degrading polymer matrix and increases the melt viscosity for blends at high temperature. The phosphorus-containing fragments which might have been released into the gas phase are locked in the condensed phase due to CC bonds cross-linking, thus forming more high-quality phosphorus-rich char layers. This effect balances the distribution of gas-phase and condense-phase flame-retardant effects and is especially obvious in PET/polyphosphonate blends containing +3-valence phosphorus, which originally plays mainly the role of a gas-phase flame retardant. PET blends containing unsaturated carbon-carbon double bonds display better carbon formation, flame-retardant activity and anti-dripping behavior than these do without this feature.

The effect of mixing sequence on synthesis of PP-g-GMA compatibilizer for multilayer packaging (MLP) compounding

Melt recycling Multilayer Packaging (MLP) waste is difficult due to challenging separation procedures. However, blending techniques with compatibilizers can simplify MLP waste melt recycling. PP-g-GMA is a common compatibilizer in polyolefin and PET blends. PP-g-GMA compatibilizer was synthesized by utilizing an internal mixer at 175℃, 50 rpm, and 10 min using styrene as a comonomer. Titration was a method to examine effect of three different sequences of adding the BPO initiator on GMA grafting. Each sequence's PP-g-GMA samples were compounded with MLP waste using a twin-screw extruder and injection molded to make tensile test specimens. FTIR analysis shows that the GMA and Styrene monomers had grafted onto the PP polymer backbone, with the GMA grafting degree by varying mixing sequence. Sequence 3, which introduced initiator, GMA, and styrene simultaneously to PP melt, yielded PP-g-GMA with the most significant GMA grafting degree of 5.11%. Adding PP-g-GMA produced from sequence 3 into the MLP melt enhanced the highest increase in tensile strength and elongation at break of the MLP/PP-g-GMA compound.

Superior glycidol-free chain extenders for post-consumer PET bottles and PET thermoform blends

The development of non-toxic, glycidol-free chain extenders is essential for enabling the recycling and reuse of both bottle-grade PET (PET-B) and thermoform PET (PET-T) in the packaging industry without the need for separation, thereby addressing the health concerns associated with commercial glycidol-based extenders. Herein, two novel series of novel glycidol-free chain extenders for bottle-grade recycled polyethylene terephthalate (PET-B) and thermoform-grade PET (PET-T) blends are reported. Blends of PET-B with up to 20 wt% of PET-T were incorporated into novel epoxy acrylate chain extenders with terminal (PEAT-BA) and internal (PEAI-BA) epoxy groups. These chain extenders are glycidol-free and improve the mechanical, rheological, and thermal properties of the PET-B/PET-T blends, offering better performance enhancements than are provided by commercial chain extender Joncryl ADR (J). The results showed significant improvements in intrinsic viscosity and mechanical properties by around 10 and 15 %, respectively, without affecting thermal properties. These findings can play a role in enabling the recycling and re-use of PET-B and PET-T blends without requiring separation while offering glycidol-free solutions.

Synergistic effect of a dual-functional SbB-g-GMA compatibilizer and Cloisite 30B on the functional properties of PET and PS blends for recycling purposes

Synergistic effect of a dual-functional SbB-g-GMA compatibilizer and Cloisite 30B on the functional properties of PET and PS blends for recycling purposes

Properties of Bitumen Modified with Nanoclay/Pet (Polyethylene Terephthalate) Blend

As the world continues to urbanize, the construction of transportation highway continuously requires quality pavement which made transportation engineers and experts focus on improving the performance and life of pavements, to which many studies had searched for better materials or modifications that could improve the properties of bitumen and reduce or even eliminate the development of asphalt pavement failures. To this end, the properties of bitumen modified with blend of PET + nanoclay was conducted. The bitumen was modified with PET (0.5 – 4.0% at 0.5% interval), and nanoclay (1.0 – 8.0% at 1% intervals), while the tests conducted on the materials were oxide composition test, Fourier Transform Infrared Spectroscopy (FTIR) test, penetration test, solubility test, ductility test, flash and fire point test, specific gravity test, softening point test, and viscosity test in accordance with codes and specification. Results from the findings showed that the unmodified bitumen and PET are hydrocarbon materials, while the nanoclay is an inorganic compound and a good reactive pozzolana. More results from the findings showed that the properties of bitumen was improved with addition of PET and nanoclay blend such that the penetration and solubility of bitumen decreases with increase in modifier content, and there was an increase in softening point, flash point, fire point, specific gravity, and viscosity of bitumen as replacement of PET and nanoclay blend increases. Hence, the modifiers (Nanoclay/PET blend) can be used to improve properties of bitumen since they fall within standard and code specification.

Rheological behavior of recycled poly(ethylene terephthalate) /poly(amide) 11 blends with chain extender

There has been a remarkable surge in global demand for plastics, resulting in a significant increase in the generation of plastic waste. This, in turn, has led to a growing environmental concern. One global study ranked Malaysia as the eighth highest contributor to marine plastic pollution. Among various strategies, mechanical recycling emerges as a practical, economically viable, and environmentally efficient method for repurposing plastic waste. Nonetheless, the challenge of hydrolytic and thermal degradation of polyester macromolecules complicates the production of blends containing poly(ethylene terephthalate) (PET). An innovative solution to the plastic waste problem lies in leveraging polymer blends sourced from these waste materials, offering a potential remedy to recycling complexities. Blending of PET and poly(amide) 11 (PA11), a bio-derived polymer has demonstrated enhanced toughness and barrier properties for PET. Joncryl has been found to be an efficient chain extender as well as compatibilizer for other polymer blends. This paper focus on the effects of various content of Joncryl ADR 4468 (0,2,4 phr) as chain extender for recycled poly(ethylene terephthalate) /poly(amide) 11 (rPETPA11) blends on rheological behavior. The rPETPA11 ratio is fixed at 80:20 based on prior research. Capillary rheometry was employed to determine the rheological behavior and thermal stability of the blends at 280 °C. The presence of 2 and 4 phr Joncryl results in increased apparent viscosity of the rPETPA11 blends. Notably, the apparent viscosity remains stable for 45 min with the addition of 2 and 4 phr Joncryl. The assessment of thermal stability should be extended to further evaluate the effects of the chain extender on the degradation kinetics of rPETPA11 blends.

Exploration of fibers produced from petroleum based-mesophase pitch and pet blends for carbon fiber production

Exploration of fibers produced from petroleum based-mesophase pitch and pet blends for carbon fiber production

Advanced Plastic Waste Recycling-The Effect of Clay on the Morphological and Thermal Behavior of Recycled PET/PLA Sustainable Blends.

Bio-based polymers such as poly(lactic acid), PLA, are facing increased use in everyday plastic packaging, imposing challenges in the recycling process of its counterpart polyester poly(ethylene terephthalate), PET. This work presents the exploration of the properties of PET/PLA blends with raw materials obtained from recycled plastics. Several blends were prepared, containing 50 to 90% PET. Moreover, multiscale nanocomposite blends were formed via melt mixing using different amounts and types of nanoclay in order to study their effect on the morphology, surface properties, and thermal stability of the blends. The materials were characterized by X-ray diffraction analysis (XRD), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). The nanoclay was found to exhibit a uniform dispersion in the polymer matrix, presenting mainly intercalated structures with some exfoliated at low loading and some agglomerates at high loading (i.e., 10%). The addition of nanoclay to PET/PLA matrices increased the roughness of the blends and improved their thermal stability. Thermal degradation of the blends occurs in two steps following those of the individual polymers. Contamination of rPET with rPLA results in materials having poor thermal stability relative to rPET, presenting the onset of thermal degradation at nearly 100 °C lower. Therefore, important information was obtained concerning the recyclability of mixed PET and PLA waste. The perspective is to study the properties and find potential applications of sustainable blends of recycled PET and PLA by also examining the effect of different clays in different loadings. Therefore, useful products could be produced from blends of waste polyester.

Optimization of Textile Waste Blends of Cotton and PET by Enzymatic Hydrolysis with Reusable Chemical Pretreatment.

Textile waste usually ends up in landfills and causes environmental pollution. In this study, pretreatment methods for textile recycling, including autoclaving, freezing alkali/urea soaking, and alkaline pretreatment, were applied to textile waste with various cotton/polyester blending ratios. The best condition for enzymatic hydrolysis was a 60/40 textile waste blend of cotton/polyethylene terephthalate (PET) with a reusable chemical pretreatment (15% NaOH) at 121 °C for 15 min. The hydrolysis of pretreated textile waste by cellulase was optimized using response surface methodology (RSM) based on central composite design (CCD). The optimized conditions were 30 FPU/g of enzyme loading and 7% of substrate loading, which resulted in a maximum observed value of hydrolysis yield at 89.7%, corresponding to the predicted value of 87.8% after 96 h of incubation. The findings of this study suggest an optimistic solution for textile waste recycling.

Thermal behavior, synergistic effect and thermodynamic parameter evaluations of biomass/plastics co–pyrolysis in a concentrating photothermal TGA

The heating rate would significantly impact the pyrolysis process, especially for the reactions containing synergistic effects between two different feedstocks. Co-pyrolysis of two widely available biomass (CC–corncob and PS–peanut shell) with plastic (PET–polyethylene terephthalate and PVC–polyvinyl chloride) was studied in a concentrating photothermal thermogravimetric analysis (CP-TGA) system at three heating rates (100, 500, 1000℃/min). The TG and DTG curves of CC and PS differ due to their polymeric components (holocellulose and lignin); two pronounced levels at 100 and 500 ℃/min heating rates were present in PVC. With increasing heating rate, the lateral shift towards higher temperature regions in the TG and DTG curves exceeded 100 °C. The synergistic effects on the blend samples were concentrated in the main decomposition region (250–580℃) due to rapid volatiles release, and the discrepancy values further stabilized at the final decomposition stages. The activation energy (Ea) was assessed using a comparative study of isoconversional methods, namely Kissinger–Akahira–Sunose (KAS), Flynn–Wall–Ozawa (FWO), and Starink. The isoconversional methods demonstrated that the co-pyrolysis process required about 30 % less activation energy than the pyrolysis of plastic (PET/PVC) alone. Coats-Redfern's (CR) model-fitting approach was used to identify the kinetic triplet of the devolatilization stage. The CR models revealed that biomass–PET blends belong to two to four-dimensional diffusion models, whereas biomass–PVC blends are dominated by chemical reactions of 1.5 and 2 orders. The energy barrier between activation energy (Ea) and change in enthalpy (ΔH) for all the blend samples was lower (∼5–6 kJmol−1), which slightly increased at higher heating rate.

Mechanical Properties of Injection Molded PP/PET-Nanofibril Composites and Foams

The creation and application of PET nanofibrils for PP composite reinforcement were studied. PET nanofibrils were fibrillated within a PP matrix using a spunbond process and then injection molded to test for the end-use properties. The nanofibril reinforcement helped to provide higher tensile and flexural performance in solid (unfoamed) injection molded parts. With foam injection molding, the nanofibrils also helped to improve and refine the microcellular morphology, which led to improved performance. Easily and effectively increasing the strength of a polymeric composite is a goal for many research endeavors. By creating nanoscale fibrils within the matrix itself, effective bonding and dispersion have already been achieved, overcoming the common pitfalls of fiber reinforcement. As blends of PP and PET are drawn in a spunbond system, the PET domains are stretched into nanoscale fibrils. By adapting the spunbonded blends for use in injection molding, both solid and foamed nanocomposites are created. The injection molded nanocomposites achieved increased in both tensile and flexural strength. The solid and foamed tensile strength increased by 50 and 100%, respectively. In addition, both the solid and foamed flexural strength increased by 100%. These increases in strength are attributed to effective PET nanofibril reinforcement.

A New Approach to Recycling PET Bottles by Blending Polyethylene- Terephthalate and HDPE Using Chemical Reactions in One Step Process

The overall goal of this study is to propose a new approach to simplify the recycling process for producing high quality material from the waste of beverage bottles and other sources at a lower cost by using mechanical recycling and chemical reactions inside injection molding machines in a one-step process. The water and soft drink bottles are made of PET material, while the caps are made mainly of HDPE. The blends of PET and HDPE are incompatible. The resulted material has poor mechanical properties due to the immiscibility of polymer blend components, phase separation, and lack of interfacial adhesion. (HDPE-g-MA) was found to be an excellent reactive compatibilizer for the PET/HDPE blend. For the purpose of investigating the mechanical and morphological properties in this study, blends of rPET and virgin HDPE in weight compositions of 80/20, and 60/40 were modified with concentrations of 2 and 5 wt percent of (HDPE-g-MA). The addition of 4,4-Methylenebis (phenyl isocyanate) and compatiblizer increased the viscosity and molecular weight of the blends while also improving miscibility and interaction bonds between molecules, resulting in a significant reduction in interfacial tension and improved phase dispersion and adhesion via interpenetration and entanglements at the interface. The rPET segments have been grafted onto HDPE backbone chains. Since the crystallinity of HDPE is low, the crystallinity and crystallization temperature of rPET in the blends were reduced. The mechanical characteristics were improved by achieving uniform phase morphology. The main finding of this study is that the immiscible rPET/HDPE materials can be treated and processed in a single step inside the injection molding process. The one-step process is sufficient because it shows high improvement in the mechanical characteristics, while the two-step process, namely the extrusion followed by injection molding, improves fewer mechanical characteristics and is more expensive.

Interactions of PP-PET blends modified by montmorillonite with different polarities

This paper describes the effects of adding organic montmorillonite clays (MMT) with different polarities (one polar and one non-polar) in recycled poly (ethylene terephthalate) (PET) and polypropylene (PP) blends. Styrene-Ethylene/Butylene-Styrene-maleic anhydride-graft (SEBS-g-MA) was used as a compatibilizer. MMT polarity was chosen based on the expected specific interaction of each clay with PET and PP. Samples were evaluated by wide angle X-ray diffraction, scanning electronic microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, dynamic mechanical analysis and mechanical tests. The clays caused no statistical change in the mechanical properties high-concentration PET blends, but increased Young’s modulus and decreased the elongation at break, tensile strength and impact strength of high-concentration PP blends. The different interactions between PET and SEBS-g-MA and the level of MMT exfoliation in each polymer-rich phase explained the results.

Extruded-Calendered Sheets of Fully Recycled PP/Opaque PET Blends: Mechanical and Fracture Behaviour.

This work presents the experimental results of the mechanical and fracture behaviour of three polymeric blends prepared from two recycled plastics, namely polypropylene and opaque poly (ethylene terephthalate), where the second one acted as a reinforcement phase. The raw materials were two commercial degrees of recycled post-consumer waste, i.e., rPP and rPET-O. Sheets were manufactured by a semi-industrial extrusion-calendering process. The mechanical and fracture behaviours of manufactured sheets were analyzed via tensile tests and the essential work of fracture approach. SEM micrographics of cryofractured sheets revelated the development of in situ rPP/rPET-O microfibrillar composites when 30 wt.% of rPET-O was added. It was observed that the yield stress was not affected with the addition of rPET-O. However, the microfibrillar structure increased the Young’s modulus by more than a third compared with rPP, fulfilling the longitudinal value predicted by the additive rule of mixtures. Regarding the EWF analysis, the resistance to crack initiation was highly influenced by the resistance to its propagation owing to morphology-related instabilities during tearing. To analyze the initiation stage, a partition energy method was successfully applied by splitting the total work of fracture into two specific energetic contributions, namely initiation and propagation. The results revelated that the specific essential initiation-related work of fracture was mainly affected by rPET-O phase. Remarkably, its value was significantly improved by a factor of three with the microfibrillar structure of rPET-O phase. The results allowed the exploration of the potential ability of manufacturing in situ MFCs without a “precursor” morphology, providing an economical way to promote the recycling rate of PET-O, as this material is being discarded from current recycling processes.

Application of low-grade recyclate to enhance reactive toughening of poly(ethylene terephthalate)

This paper presents a new recognition in reactive toughening of poly(ethylene terephthalate) (PET), namely the major effect of the molecular weight of PET on the evolution of the compatibilization and crosslinking reactions with ethylene‑butyl acrylate-glycidyl methacrylate (EBA-GMA) type reactive terpolymer, and thus indirectly on its toughening efficiency. It was found that the use of highly degraded recycled PET (rPET) grades, due to the available larger number of reactive functional end groups and increased mobility of the decreased-molecular-weight chains, multiplies the impact strength of the product compared to that of original PET (oPET) with identical EBA-GMA contents. The evinced noticeable difference between the toughening behaviour of rPET and oPET is explained by morphological and interfacial factors and connected to differences in rheological behaviour as well. The reactive oligomeric rPET macromolecules form a Toughening Enhancer Interphase (TEI) around the dispersed particles. Based on systematic analyses, conclusions were drawn regarding the quality, i.e. optimal intrinsic viscosity (IV) range, and quantity of rPET to be used to obtain high-impact-strength PET blends (notched Izod impact strength higher than 40 kJ/m2) with optimised mechanical properties, being suitable even for injection moulding applications, at significantly lower terpolymer contents (10.0–12.5 wt%) than expected. Besides, the proposed new way of utilisation of PET recyclates, especially the unmarketable highly degraded fractions, is believed to give a new driving force in PET recycling.

Blend Miscibility of Poly(ethylene terephthalate) and Aromatic Polyesters from Salicylic Acid.

Poly(ethylene terephthalate) (PET) is one of the most prevalent polymers in the world due to its combined thermal, mechanical, and gas barrier attributes. Blending PET with other polymers is an appealing strategy to further tailor properties to meet the needs of an even more diverse range of applications. Most blends with PET are macrophase-separated; only a few miscible systems have been reported. Here, the miscibility of the aromatic polyesters poly(salicylic glycolide) (PSG) and poly(salicylic methyl glycolide) (PSMG) with PET is described. Both PSG and PSMG have similar chemical structures to PET but are derived from sustainable resources and readily degradable. This study suggests that they are fully miscible with PET over the entire composition range, which is attributed to favorable interactions with PET. Negative polymer-polymer interaction parameters (χ) were determined using Flory-Huggins theory to describe melting temperature variations in the blends. In addition, the PET blends showed mechanical properties that are intermediate between the two homopolymers.

Effect of Copoly(Ester-Amide 6)(PET-PA6) on Compatibility of PET/PA6 Blended Fibers

Significant improvement of compatibility in PET/PA6 blends is essential to obtain fibers having enough mechanical strength as well as the comprehensive performance. In this article, copoly (ester-amide 6) was used as compatibilizer to improve the compatibility of PET and PA6. Three copoly (ester-amide 6) s with 5, 10% content of PA6 were prepared by co-polymerization from PTA , EG, as well as PA6 or caprolactam (A6), i.e. polyamide was incorporated both in the form of polymer and monomer, respectively. The sequence length of PET in the copoly (ester-amide 6) s is 33.4, 16.5 and 38.4 for PET-PA6-5%, PET-PA6-10% and PET-A6-5%, respectively, calculated by 13C NMR. Then PET/PA6 blend fibers were fabricated by melting spinning of PET and PA6 with 20 %wt addition of PET-PA6-5%, PET-PA6-10% and PET-A6-5%, respectively, to explore the effect of copoly (ester-amide 6) s on compatibility of PET/PA6 blend fibers, where the mass ratio of PET and PA6 is 85/15. DSC results show that the crystallization peaks of PET and PA6 during cooling from the blend melt become adjacent each other with increasing addition of copoly (ester-amide 6) s, even forming fused crystallization of them. It was found from SEM that the size of PA6 phase decreased and the phase boundary became indistinct due to the presence of copoly (ester-amide 6) s. Further more, the glass transition temperatures (Tg) of PET and PA6 closed to each other based on DMA result. Among these three copoly (ester-amide 6) s, PET-A6-5% display the best effect on the compatibility of PET and PA6 blend fiber, suggesting copoly (ester-amide 6) s could play important role in raise the compatibility of PET and PA6 blend.

Influence of multiple extrusions of blends made of polyethylene terephthalate and an oxygen scavenger on processing and packaging-related properties

We investigated the influence of multiple extrusions of poly-(ethylene terephthalate) (PET) blended with a polymer-based oxygen scavenger. PET and PET blended with an oxygen scavenger additive were extruded up to four times to polymer strands. They were chilled in a water bath and cut to granules. Between the extrusions, the granules were dried at (only) 60°C to avoid the oxygen scavenger losing its reactivity. The water content was up to 0.5 wt.-% and therefore up to factor 100 higher than the recommended water content for PET extrusion. For further analysis, films were extruded and bottles were stretch-blow-molded. Due to polymer degradation and the recycled PET blend viscosity being too low, this material had to be blended with virgin PET in order to be processable. We used 33 wt.-% recycled PET and 66 wt.-% virgin PET ratio. The impact of the thermomechanical stress by multiple extrusions was investigated by several test methods: analysis of the melt pressure in the extruder barrel during extrusion, intrinsic viscosity and melt flow rate, microscopy, differential scanning calorimetry, color value measurements (L*a*b* values), tensile testing, compression testing, and oxygen absorption measurements. The intrinsic viscosity reduced after four re-extrusions in a compounder from 0.82 dl/g to 0.35 dl/g for PET with scavenger and to 0.41 dl/g for pure PET. This, even though low, difference can be explained by the slightly higher PET degradation due to the oxygen scavenger. We found slightly better mechanical properties (yield stress, Young’s modulus) for pure PET films compared to PET blended with an oxygen scavenger. At up to three extrusions, there was little influence on these properties. The extruded material with 3 wt.-% oxygen scavenger additive has an oxygen absorption capacity of 9.5 mg oxygen per 1 g of granules, i.e., the scavenger additive absorbed about 300 mg oxygen per 1 g of additive. Our results are relevant for in-house recycling processes of PET with oxygen scavenger.

Synthesizing PET and food waste into refuse plastic fuel (RPF): optimization and kinetic modeling

With rapid urbanization and industrialization, cheap energy supply from fossil fuels has become a problem of great extent, due to the rising fuel prices and greenhouse gas emissions. RPF is becoming the center of research as it is a waste-to-energy conversion concept and provides an alternative energy source. In this research, RPF is made equivalent to the energy content of coal by mixing 60% PET bottles and 40% of food waste. RPF blend and the raw materials were characterized for energy content by using the bomb calorimeter. Compositional analysis of the original samples of PET, food waste and RPF blend with their respective burnt-out char samples was performed by comparing the EDS results. Kinetic study of the synthesized RPF blend was done with TGA at three different temperature increments of 5 °C min−1, 10 °C min−1 and 15 °C min−1. The Friedmann model was applied for the non-isothermal modeling to calculate the activation energy and the Arrhenius factor. The minimum activation energy value for RPF blend was found out to be 15.753 kJ mol−1 for TGA with a heating increment of 5 °C min−1. Synthesized RPF found to require approximately 12 times less activation energy in comparison with PET and 4–10 times less than coal depending upon the coal type. For Pakistan, PET and food waste can provide daily 11,550 RPF energy blocks each of 1 ton with 256 Million MJ of energy which give 71,000 MW of electricity daily that could fulfill energy gap in the country.

Different carbon fibrous morphologies triggered by varying the average diameter of precursor electrospun fibers

Investigation of the factors affecting the carbonization process is very important for the manufacture of desired, on-demand carbon fibrous morphologies. In this work, the effect of the average fiber diameter on the carbonization of precursor polymer fibers into carbon fibers was examined. Three electrospun fibrous mats consisting of a lignin/recycled PET blend with mass ratio of 1/1 and having different average fiber diameter (80, 387 and 781 nm) were prepared. After they were carbonized at 600 °C, it was found that the thicker fibers (387 and 781 nm) yield well-formed carbon fibrous morphologies, with average diameter of the same range as the precursor ones. In contrast, the thinnest nanofibers with an average diameter of 80 nm fuse with each other and lose their fibrous morphology, due to the maximization of heat and mass transfer during the process. These results highlight the decisive role of the nanoscale dimension in processes controlled by heat and mass transfer phenomena, as in the case of carbon fiber manufacture.