Aliphatic-aromatic Copolyester Research Articles

Thermal degradation of random copolyesters based on 1,4-butanediol, terepthalic acid and different aliphatic dicarboxylic acids

Thermal stability and degradation kinetics have been studied for a series of aliphatic-aromatic copolyesters where the terephthalate content was varied between 30 mol-% and 70 mol-%. Succinate, adipate and sebacate were considered as the aliphatic dicarboxylate unit. All copolyesters were synthesized with a perfect random distribution by a thermal transesterification process from the corresponding homopolyesters.A complex degradation was deduced for all copolymers taking into account the increment of the activation energy with conversion. In fact, thermogravimetric curves showed a minor decomposition process in the low conversion region that was more significant for the succinate derivative and specifically for that having the lowest aromatic content. The sebacate derivative was characterized by the presence of an additional and minor decomposition process that took place at the highest conversion.All copolyesters were defined by a major decomposition process, which has similar values of activation energy regardless of the method used to calculate them (e.g. Kissinger, KAS or Friedman methodologies). This decomposition reaction followed a A4 Avrami-Erofeev mechanism when Coats-Redfern and Criado methodologies were applied. In summary, all the studied copolymers thermally decompose following a complex process but in all cases the main degradation step corresponds to a similar degradation mechanism.

Diamond Green Diesel to expand renewable fuel capacity using Ecofining technology from Honeywell UOP

Biodegradability of polyesteramides prepared by anionic ring-opening copolymerization of ε-caprolactone and ε-caprolactam and of aromatic-aliphatic co-polyesters (PETP/LA) synthesized by solvolysis of poly(ethyleneterephthalate) with water solutions of lactic acid by microorganisms producing extracellular esterase and lipase was investigated. The bacterium Pseudomonas aeruginosa, yeast Candida guilliermondii and micromycete Aspergillus fumigatus exhibiting strong esterase and lipase activities on agar plates with artificial nitrophenyl substrates were selected to be used in six-week degradation experiments at 28°C. PETP/LA samples exhibited mass reductions of up to 5-10% in both the presence of the three microorganisms and in abiotic controls where the polymers were exposed only to Nutrient Broth or malt extract-glucose medium. Scanning electron microscopy revealed breaks in PETP/LA fibres when polymers were exposed to A. fumigatus and C. guilliermondii, attributable to microbial action. Polyesteramides were resistant to biodegradation. Degradation of both polymer types resulted in a 5-10-fold increase of toxicity of culture supernatans measured with Vibrio fischeri bioluminescence test and Sinapis alba germination plant test, as compared to the biotic and abiotic controls. No genetic toxicity was detected with Salmonella typhimurium His- test. The study suggests that ecotoxicity of compounds produced by biodegradation of polymers should be monitored.

Self‐Organization of Hyperbranched Polyesters Functionalized with Pyrrolo[2,1‐a]isoquinoline End Groups and Their Fluorescent Recognition of Anthracene and Pyrene

The structurally controllable hyperbranched aromatic–aliphatic copolyesters HBPE‐MPICB4 and HBPE‐MPICB2 are synthesized by incorporating the periphery of a second‐generation hyperbranched polyester (HBPE) with methylpyrrolo[2,1‐a]isoquinoline‐1‐carbonitrile(E)‐4‐oxo‐[2‐(oxo‐λ3‐methyl)hydrazinyl]but‐2‐enoate (MPICB) groups via one‐pot synthesis. Organized supramolecular structures are self‐assembled in different organic media. Lamellar structure with a length of around 10 µm can be obtained in ethyl acetate. However, the identical HBPE‐MPICB4 and HBPE‐MPICB2 building blocks can self‐organize into flower‐like and vesicular structure in ethanol, with particle sizes around 12 and 5 µm, respectively. The noncovalent interactions of HBPE‐MPICB4 and HBPE‐MPICB2, that is, hydrogen bonding and π–π stacking, are critical for the construction of organized structures. Furthermore, host–guest recognitions by HBPE‐MPICB4 and HBPE‐MPICB2 are investigated by fluorescence studies. The results indicate that HBPE‐MPICB4 microflowers respond selectively to anthracene and pyrene through π–π stacking interactions. image

Enzyme Production During Composting of Aliphatic–Aromatic Copolyesters in Organic Wastes

Abstract Monitoring of various enzymes' production throughout the process provides useful information on the dynamics of composting and is beneficial for understanding the transformations occurring during composting. In this study, aliphatic–aromatic copolyesters with different polyethylene terephthalate/poly(lactic) acid ratios were subjected to laboratory-scale and full-scale composting conditions. Activities of hydrolase (urease, protease, lipase, and cellulase) and dehydrogenase were monitored during 21 days to better understand the effect of polymer presence on enzyme production. After 7 days, a significant increase in lipase, protease, and cellulase activities in compost soil with polymer indicates qualitative and quantitative changes in the content of particular organic polymers, probably due to polymer degradation. This observation was more pronounced for copolyesters A and B and also for reference material—model aromatic oligomer. This result is in correlation with dehydrogenase activity, which r...

Classification of aliphatic-butylene terephthalate copolyesters in relation to aliphatic/aromatic ratio

Aliphatic-aromatic copolyesters containing: butylene terephthalate ester and a mixture of butylene esters: adipate, succinate and glutarate, (PBASGT), were synthesized and classified according to their chemical composition and physical performance. Several such mixtures of aliphatic dimethyl esters are available on the market. Structures and properties of PBASGTs were characterized by various techniques including 1H NMR spectrometry, calorimetry, x-ray scattering and diffraction, dynamic mechanical analysis and tensile testing. All copolyesters were nearly random copolymers. Surprisingly, only the aromatic component is able to crystallize in the form characteristic for poly (butylene terephtalate). The increase of aromatic units content did not change the crystallographic form, however, a stronger crystallinity develops. The dramatic changes of thermal and mechanical properties of PBASGT were observed with the increase of aliphatic units content, e.g. from brittle to tough behavior. Copolyesters with aromatic content of 30% and below exhibit single relaxation peak of aliphatic rich amorphous components. At the concentration of 40% and above the aromatic component is segregated while the amorphous aliphatic units form joint pools. A partial segmental miscibility of aromatic and aliphatic components is suggested. It was shown that PBASGT with 40% of aromatic units is biodegradable.

Fully bio-based aromatic–aliphatic copolyesters: poly(butylene furandicarboxylate-co-succinate)s obtained by ring opening polymerization

Fully bio-based poly(butylene furanoate-co-succinate) copolyesters were synthesized by ring opening polymerization using either organometallic or enzymatic catalysis.

Hydrolytic and thermal oxidative degradation behavior of thermotropic aromatic–aliphatic copolyesters

In this study, the hydrolytic and thermal oxidative degradation behavior of thermotropic aromatic–aliphatic copolyesters based on 4-hydroxybenzoic acid (HBA), 4-hydroxy-3-methoxybenzoic acid (VA), poly(butylene terephthalate) (PBT) and lactic acid (LA) have been investigated. The hydrophilicity and alkaline hydrolytic degradation rate of copolyesters increased with increasing LA contents. FTIR, DSC and TG results suggested that breakage of molecular chain mainly took place on aliphatic segments and also amorphous part. SEM analysis indicated the hydrolytic degradation followed surface corrosion mechanism. The dynamic TG results showed that all copolyesters exhibit total mass loss and two degradation stages under air atmosphere. The thermal oxidative degradation kinetics were evaluated by Kissinger and KAS method. The dependence of E values on conversion α has been observed in selected conversion range for all copolyesters, indicating complex degradation reaction existed.

Influence of Specific Processing Conditions and Aliphatic-Aromatic Copolyester on Polylactide Properties

This study reports the influence of aliphatic-aromatic copolyesters (AAC) on selected polylactide (PLA) properties. Processing, mechanical, and thermal properties were determined. In addition, we examined changes occurring in the surface geometrical structure of sample fractures. It was found that PLA as modified with AAC exhibited enhanced impact strength and melt flow rate, unaffected elongation at break, and reduced tensile strength and elasticity modulus. The results also demonstrate the plasticizing properties of AAC, which improved PLA processing and its thermal stability. We also observed insufficient adhesion at the interface between the two components, as well as heterogeneity of the obtained material.

Poly(butylene adipate-co-terephthalate) scaffolds: processing, structural characteristics and cellular responses

ABSTRACTThe aliphatic-aromatic copolyester, poly(butylene adipate-co-terephthalate) (PBAT) combines good mechanical and thermal properties with biodegradation ability. However, until now, researches in its potential medical use remain limited. Only in a few studies blends of PBAT with routinely used biocompatible polymers had been prepared and investigated regarding tissue engineering applications. Therefore, in this study, we decided to determine processability of neat PBAT as a scaffold material for bone tissue by using different fabrication methods i.e. solvent evaporation, electrospinning, solvent casting-particulate leaching (SCPL) and melt molding-particulate leaching. The results of physicochemical characterizations and cell culture studies with MC3T3-E1 preosteoblasts confirmed that neat PBAT has favorable characteristics for bone tissue engineering, however, fabrication method strongly affects the cellular responses. Regarding to the characterizations and cell cultures, PBAT scaffolds produced by SCPL and electrospinning are proposed to be used for bone tissue engineering.

PLA/PHA-Biodegradable Blends for Pneumothermic Fabrication of Nonwovens

Abstract This study presents the results of research concerning fabrication of nonwovens from biodegradable polymer blends using the melt-blown method. The experiments performed within the framework of the research confirmed the possibility of obtaining polymer composites based on polylactide (PLA) with poly(hydroxyalkanoates) (PHA) and another aliphatic-aromatic copolyester. The obtained products were subjected to the analyses of chemical structure using the Fourier Transform Infrared Spectroscopy(FTIR) Attenuated Total Reflectance(ATR) method. The physical and mechanical properties of the fabricated nonwoven layers were also tested, which confirmed a wide spectrum of their applicability, depending on the polymer composition used in production.

Application of the electron radiation and triallyl isocyanurate for production of aliphatic-aromatic co-polyester of modified properties

Investigation of the effect of electron radiation and triallyl isocyanurate (TAIC) on the mass melt flow rate, average molecular weight, density, mechanical properties, as well as formation of the gel fraction of poly(butylene adipate-co-terephthalate) (PBAT) was the main objective of the present work. It was found that irradiation of PBAT by electron radiation causes mutual linking of PBAT macromolecules at chain ends or create branched structures. At the same time, the gel fraction does not form and inhibition of flow does not occur. It was also found that PBAT irradiated in the presence of TAIC underwent crosslinking resulting in formation of a significant amount of the gel fraction. Moreover, TAIC by itself does not cause crosslinking of this polymer. It grows also tensile strength and density of irradiated samples containing TAIC, and the elongation at break decreased. The extent of observed changes essentially depends on the magnitude of the electron radiation dose.

Synthesis and Characterization of Aliphatic-Aromatic Copolyesters PET-PLA from PET Waste and Lactide

Synthesis and Characterization of Aliphatic-Aromatic Copolyesters PET-PLA from PET Waste and Lactide

Effect of composting plant material with copolyester on quality of organic matter

Abstract The problem of incorporating plastics into the environment will be aggravating, both regarding its scale and kind of these materials. Investigations were carried out using aliphatic-aromatic copolyester poly (succinate-co-glutarate-co-adipate-co-terephthalate 1,4-butylene) with addition of fatty acid dimers. The work aimed to determine the effect of composting the copolyester with plant biomass on changes of fractional composition of humus substances and their stability. Copolyester was supplemented to the biomass in the form of a nonwoven fabric in two doses. It constituted 8 and 16% of the dry mass of the composted substrates. The composting process was run within two ranges of ambient temperature 25-30°C and 40-45°C. After the completion of this process, the degree of material maturing was assessed using manometric methods and the carbon content was analysed in the individual organic matter fractions. On the basis of cumulated respiratory activity AT4 a lack of composted material activity was revealed in the higher temperatures of the process. However, in the objects where copolyester was transformed in the lower temperatures this activity was considerably diversified. Adding copolyester to the composted biomass led to a diversification of the Cha : Cfa ratio. The values of Cha : Cfa ratio most approximating 1.5, ie the value regarded as optimal, were registered in the object, where copolyester supplement constituted 16% and the plant biomass was maintained within the 40-45°C temperature range.

Investigations on Preparation and Characterization of Certain Copolyesters

In this paper, we report on the synthesis and characterization of high molecular weight copolyesters from Terephthalic acid, 1, 4 butane diol and Succinic acid /Sebacic acid through a two step process of melt polycondensation using titanium tetra butoxide as catalyst. The synthesized aromatic-aliphatic random copolyesters were characterized by means of FTIR, 1H NMR,13C NMR, Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), Gel Permeation Chromatography (GPC) and Scanning Electron Microscope (SEM) studies. The effect of copolymer composition on the physical and thermal properties as well as degradation test was investigated. The degradation test was carried out in alkali medium. The phase behaviour of the polymers was studied by differential scanning calorimetry and optical polarising microscopy. The results revealed that the newly synthesized copolyesters exhibited degradability and thermotropic liquid crystalline behaviour with nematic texture which was revealed by optical polarising microscopy. The Novelty of this work is that the glass transition temperature and melting temperature are above the room temperature for the synthesized polymers. This shows the good thermal stability which results in early processing of liquid crystalline materials.

Data on synthesis of oligomeric and polymeric poly(butylene adipate-co-butylene terephthalate) model substrates for the investigation of enzymatic hydrolysis.

The aliphatic-aromatic copolyester poly(butylene adipate-co-butylene terephthalate) (PBAT), also known as ecoflex, contains adipic acid, 1,4-butanediol and terephthalic acid and is proven to be compostable [1], [2], [3]). We describe here data for the synthesis and analysis of poly(butylene adipate-co-butylene terephthalate variants with different adipic acid:terephatalic acid ratios and 6 oligomeric PBAT model substrates. Data for the synthesis of the following oligomeric model substrates are described: mono(4-hydroxybutyl) terephthalate (BTa), bis(4-(hexanoyloxy)butyl) terephthalate (HaBTaBHa), bis(4-(decanoyloxy)butyl) terephthalate (DaBTaBDa), bis(4-(tetradecanoyloxy)butyl) terephthalate (TdaBTaBTda), bis(4-hydroxyhexyl) terephthalate (HTaH) and bis(4-(benzoyloxy)butyl) terephthalate (BaBTaBBa). Polymeric PBAT variants were synthesized with adipic acid:terephatalic acid ratios of 100:0, 90:10, 80:20, 70:30, 60:40 and 50:50. These polymeric and oligomeric substances were used as ecoflex model substrates in enzymatic hydrolysis experiments in the article “Substrate specificities of cutinases on aliphatic-aromatic polyesters and on their model substrates” [4].

Thermoplastic films containing lignin and their optical polarization properties

Abstract A soda lignin, Protobind 2400, was blended at ratios up to thirty weight percent with polyolefins or the aliphatic-aromatic copolyester Ecoflex and films were cast with a twin-screw extruder. The mechanical properties, structure, and optical properties of the resultant films were characterized by tensile tests and microscopy. Films for all blends of this modified lignin were successfully cast without operational issues. Film elongation was maintained for both the polyolefins and Ecoflex. Lignin significantly increased the modulus of the polyethylene films but decreased the modulus of the polypropylene and Ecoflex films. Lignin was found as lamellae oriented in the machine direction of the polyolefin films, but as spherical domains in the Ecoflex film. It was concluded that the oriented lamellar structure was critical to the behavior of the polyolefin-lignin blends as optical polarization films (OPFs). Additional development around improvement of this property, which for the prototypes produced here was about one-tenth the efficiency of commercially available OPFs, to produce a sustainable OPF was recommended.

Nucleation and crystallization of random aliphatic-butylene terephtalate copolyester

Aromatic component of biodegradable aliphatic–aromatic random copolyester crystallizes. A strong self-nucleation is active with self-nuclei stable below 160°C. Without self-nuclei the peak crystallization temperature decreases by 25°C during subsequent cooling. The activity of self-nuclei was incentive to find artificial nucleating agents. Green phthalocyanine, blue phthalocyanine and talc were found to be effective nucleating agents for aliphatic–aromatic copolyester in absence of self-nuclei, increasing both the peak crystallization temperature and the density of nucleation. Crystallization of aliphatic–aromatic copolyester led to the formation of spherulites filling the entire volume of the material although aromatic crystal amounted to 10% of entire volume. SAXS analysis and AFM imaging showed that crystals are neither lamellar nor aligned in stacks. Instead, the crystals are formed as narrow, 3–4nm thick fibrils radiating from spherulite centers. Crystallization of nucleated copolyester proceeds during cooling in a very peculiar way: first long fibrils are formed that partially immobilize the rest of material. During further cooling partially confined melt crystallizes in the form of short fibrils, however, in significantly smaller amount. The strangest outcome of artificial nucleation is that the crystallinity degree of nucleated copolyester is lower than nonnucleated. By short annealing at 70°C long fibrils decompose by partial melting and capillary instability freeing the material from constraints.

Synthesis and Characterization of Aliphatic-Aromatic Copolyesters From Pet Waste and ϵ-Caprolactone

Copolyesters containing aliphatic units in the main chain were obtained by reacting Bis(2-hydroxy ethyl terephthalate) (BHET) with ϵ-caprolactone (ϵ-CL) at a high temperature in bulk in the presence of tin octoate as catalyst. Various copolyesters were synthesized by using BHET/ϵ-CL mass ratio ranging from 90/10 to 10/90. Thermal properties were studied by DSC and TGA, and structural characterization was carried out by 1H-NMR spectroscopy. These techniques confirm the insertion of lactones units in PET chains. The degree of randomness of 30/70 to 60/40 copolyesters, determined by 1H-NMR, shows a random microstructure. The other copolyesters exhibit some block copolymer character.

New Copolyesters Containing Aliphatic and Bio-Based Furanic Units by Bulk Copolycondensation

A straightforward substitution of non-renewable aromatic aliphatic copolyesters by renewable homologous furanic aliphatic copolyesters was successfully realized by copolymerization of furanic unit, aliphatic and 1,3-propanediol. Different copolyesters were synthesized and characterized by 1H-NMR, 13C-NMR, FTIR, DSC and TGA. For all copolyesters, the degree of randomness, determined by 1H-NMR, was close to 1, reflecting a random distribution of furanic and aliphatic ester units in polymer chains. The hydrolytic degradation of polymers was performed at pH 4.35 at 37°C over a period of four weeks. The hydrolytic degradation proved a mass loss of about 10%.

Aliphatic-aromatic poly(ester-carbonate)s obtained from simple carbonate esters, α,ω-aliphatic diols and dimethyl terephthalate

Two reaction pathways for synthesis of high molar mass (Mw above 50 000 g/mol) aliphatic-aromatic poly(ester-carbonate)s were elaborated. Simple organic carbonates such as dimethyl carbonate or propylene carbonate were used as carbonate linkage sources and dimethyl terephthalate as the precursor of ester linkages. 1,4-Butanediol, 1,5-pentanediol, 1,6-hexanediol and 1,10-decanediol were used as diol monomers. To adjust the carbonate units content in the copolymer, solid alkylene bis(methylcarbonate) was used as a semiproduct instead of volatile dimethyl carbonate. In case of usage propylene carbonate as a starting material the process can be carried out in one pot without the need for isolation of the semiproduct. The obtained copolymers based on 1,4-butanediol, containing ca. 50 mol.% of carbonate units exhibited better mechanical strength (37 MPa) than commercially available aliphatic-aromatic copolyester Ecoflex® keeping the thermal properties at the same level.