Butylene Terephthalate Research Articles

Synthesis of bio‐based polyesters with crystallization properties comparable to poly(butylene terephthalate)

AbstractTo enhance the crystallization of poly(butylene 2,5‐furandicarboxylate) (PBF) thus substitute its petroleum‐based analogue poly(butylene terephthalate) (PBT), a series of high molecular weight poly(butylene‐co‐1,4‐cyclohexanedimethylene 2,5‐furandicarboxylate) (PBCF) copolyesters with low contents (0–19 mol%) of 1,4‐butanediol (BDO) are synthesized from 2,5‐furandicarboxylic acid (FDCA), 1,4‐cyclohexanedimethylene (CHDM) and BDO. Their chemical structures and compositions are confirmed by nuclear magnetic resonance (1H NMR and 13C NMR). Their number average molecular weights are from 20,500 to 36,100 g/mol with the polydispersity index (Ð) of 1.67–1.99. The thermal stability and crystallization behaviors are investigated by thermogravimetric analyzer (TGA) and differential scanning calorimeter (DSC). Results show that PBCFs demonstrate comparable crystallization rate to PBT as the crystallization half time is from 18 to 29 s and the melting enthalpy is 34.1–41.4 J/g as well as the higher melting temperature of 238–263°C than 225°C for PBT. In addition, PBCFs exhibit excellent mechanical properties of tensile modulus between 1220 and 1510 MPa. These investigations suggest that a moderate amount CF unit can improve the melting temperature and enhance the originally weak crystallizability of furan‐based polyesters. Generally, PBCFs can be the engineering plastic with satisfied thermal and mechanical performance.

A Modular Composite Device of Poly(Ethylene Oxide)/Poly(Butylene Terephthalate) (PEOT/PBT) Nanofibers and Gelatin as a Dual Drug Delivery System for Local Therapy of Soft Tissue Tumors.

In the clinical management of solid tumors, the possibility to successfully couple the regeneration of injured tissues with the elimination of residual tumor cells left after surgery could open doors to new therapeutic strategies. In this work, we present a composite hydrogel–electrospun nanofiber scaffold, showing a modular architecture for the delivery of two pharmaceutics with distinct release profiles, that is potentially suitable for local therapy and post-surgical treatment of solid soft tumors. The composite was obtained by coupling gelatin hydrogels to poly(ethylene oxide)/poly(butylene terephthalate) block copolymer nanofibers. Results of the scaffolds’ characterization, together with the analysis of gelatin and drug release kinetics, displayed the possibility to modulate the device architecture to control the release kinetics of the drugs, also providing evidence of their activity. In vitro analyses were also performed using a human epithelioid sarcoma cell line. Furthermore, publicly available expression datasets were interrogated. Confocal imaging showcased the nontoxicity of these devices in vitro. ELISA assays confirmed a modulation of IL-10 inflammation-related cytokine supporting the role of this device in tissue repair. In silico analysis confirmed the role of IL-10 in solid tumors including 262 patients affected by sarcoma as a negative prognostic marker for overall survival. In conclusion, the developed modular composite device may provide a key-enabling technology for the treatment of soft tissue sarcoma.

A comparative study of graphene oxide or chemically reduced graphene oxide filled poly(ethylene terephthalate)/poly(butylene terephthalate)/graphene nanocomposites

A comparative study of graphene oxide or chemically reduced graphene oxide filled poly(ethylene terephthalate)/poly(butylene terephthalate)/graphene nanocomposites

Thermoplastic matrix‐based composites produced by resin transfer molding: A review

AbstractThe recycling of thermoset‐based composites is challenging. The replacement of thermosetting resins with thermoplastics is an initial step to address this issue, together with the use of green reinforcements. Owing to the recent development of low‐viscosity thermoplastic resins, it is possible to produce thermoplastic matrix composites using the resin transfer molding (RTM) technique, which was originally conceived for the production of thermosetting matrix composites. These resins are based on cyclic esters, methyl methacrylate, and cyclic (butylene terephthalate) oligomers. This review presents the state‐of‐the‐art works reported on the production of thermoplastic matrix composites via a thermoplastic RTM (TP‐RTM) process, from the in situ polymerization of the resins through the optimization of the TP‐RTM parameters for the evaluation of the composite properties.

Acid-triggered, degradable and high strength-toughness copolyesters: Comprehensive experimental and theoretical study

The popularization and widespread use of degradable polymers is hindered by their poor mechanical properties. It is of great importance to find a balance between degradation and mechanical properties. Herein, poly(butylene terephthalate) (PBT) modified by SPG diol from 10% to 40 mol% were synthesized through a two-step polycondensation reaction. Chemical structures, thermal properties, mechanical properties, viscoelastic behavior and degradation of poly(butylene terephthalate-co-spirocyclic terephthalate) (PBST) were investigated. The SPG could toughen the copolyesters and the elongation at break of PBST20 was up to 260%. Moreover, the introduction of SPG enables to provide an acid-triggered degradable unit in the main chain. PBSTs copolymers maintain stable structures in a neutral environment, and the degradation under acid conditions will be unlocked. As tailoring the content of SPG, the degradation rate of the chain scission in response to acid stimuli will be adjusted. The acid degradation was proved to be occurred at the SPG units in the amorphous phase by DSC, XRD, GPC and 1H NMR tests. After the acid degradation, the hydrolysis rate will also be accelerated, adapting to the requirements of different degradation schedules. The plausible hydrolytic pathways and mechanisms were proposed based on Fukui function analysis and density functional theory (DFT) calculation.

Physical Properties and Polymorphism of Acrylic Acid-Grafted Poly(1,4-butylene adipate-co-terephthalate)/Organically Modified Layered Double Hydroxide Nanocomposites.

Novel and biodegradable acrylic acid-grafted poly(1,4-butylene adipate-co-terephthalate)/organically modified layered double hydroxide (g-PBAT/m-LDH) nanocomposites were synthesized through the polycondensation and transesterification process, with the covalent linkages between the polymer and the inorganic materials. X-ray diffraction and transmission electron microscopy were used to characterize the structure and morphology of the g-PBAT/m-LDH nanocomposites. The experimental results show that the m-LDH was exfoliated and widely distributed in the g-PBAT matrix. The addition of m-LDH into the g-PBAT extensively improved the storage modulus at −90 °C, when compared to that of the pure g-PBAT matrix. The effects of the minor comonomer of the butylene terephthalate (BT) unit and the addition of m-LDH on the crystallization behavior, and the polymorphic crystals of the g-PBAT at numerous crystallization temperatures, were examined, using a differential scanning calorimeter (DSC). The data indicate that the minor comonomer of the BT unit into g-PBAT can significantly change the starting formation temperatures of the α-form and ꞵ-form crystals, while a change in the starting formation temperatures of the α-form and ꞵ-form crystals using the addition of m-LDH into g-PBAT is not evident.

Solid-state modification of poly(butylene terephthalate): Design of process from calorimetric methods for catalyst investigation to reactive extrusion

The production of plastics has been increasing for more than half a century and the problem with significant growth is the waste associated with this activity. At this time, polymers are mainly recycled by classical pathway (e.g., mechanical or chemical recycling) but at the moment these techniques still present several issues (e.g., obtaining unclean material, etc.). In this study, it is proposed to reuse the materials to give them a second life by solid-state modification (SSM). This paper reports the design of a new process based on SSM technique of polyesters from batch into a continuous process. Poly(butylene terephthalate) (PBT) and 1,12-dodecanediol (DDO) are used as model compounds. At first, a calorimetric method is developed to investigate the main features of the reaction at small scale and make the proper choice of catalyst with the help of differential scanning calorimetry (DSC). At the second step, a qualitative kinetic discussion confirms our calorimetric results and the influence of the reaction time on the molecular and thermal characteristics of the copolymers obtained. The optimized conditions are then transferred to a gram-scale batch reactor and finally tested in reactive extrusion (REx) continuous process allowing to decrease the reaction time as much as possible and to test the shear forces in the SSM framework. This study therefore encompasses the design of a new process for recycling polymeric materials and offers the possibility of making polymers more sustainable.

A segment probability method for calculating the molecular weight distributions of linear polycondensates in a continuous reactor

AbstractThe molecular weight distribution (MWD) of polymers is a target of the optimization and control of industrial polymerization processes, as it dictates the processability and properties of polymers. A method, named as segment probability method, is developed to calculate the MWD of polycondensates produced by monomers of types A2 and B2 in a continuous reactor. It considers a growing chain as being composed of A and B segments in the middle of the chain and two terminal segments at the chain ends. It calculates the propagation probabilities of these different types of segments upon taking into account both the polycondensation and side reaction kinetics as well as the residence time distribution of the continuous reactor. The method is validated by poly(butylene terephthalate) (PBT) obtained from an industrial polymerization process composed of a continuous esterification reactor. The MWDs of the PBT calculated by this method are in agreement with those measured by size exclusion chromatography with mean square errors less than 10%.

Study on morphology, mechanical, thermal and viscoelastic properties of PBT/ABS/CNT nanocomposites

ABSTRACT Acrylonitrile-butadiene-styrene and carbon nanotubes were employed to enhance the notched impact toughness and high-temperature performance of poly(butylene terephthalate) based material. PBT/ABS/CNT nanocomposites were produced via melt-mixing process. At the next stage, the mechanical, thermal and morphological behaviour of nanocomposites were evaluated. Scanning electron microscopy showed a relatively uniform dispersion of ABS phase in the PBT host phase. The results of thermodynamic interfacial energy analysis implied that CNTs are localised in the PBT continuous phase. The existence of ABS droplets in PBT noticeably improved the notched impact toughness. The inclusion of carbon nanotubes into the PBT/ABS blend enhanced tensile, flexural and notched impact resistance. In addition, the incorporation of ABS and CNT in PBT considerably elevated the storage modulus at high temperature. The uniform dispersion of ABS phase and localisation of CNTs in the PBT continuous phase were key factors in the properties improvement.

Investigation of Effects of a Polymeric Chain Extender on the Properties of Recycled Poly (Butylene Terephthalate)

Poli(bütilen tereftalat) (PBT) günümüzde en fazla kullanılan poliesterlerdendir, ancak PBT atıkların geri dönüşüm kapsamında katma değerli ürünlere dönüşmesine yönelik girişimler hala sınırlıdır. PBT geri dönüşümünün en önemli zorluklarından birisi çoklu eriyik işleme döngüleri sırasındaki termal bozunma olup, polimerin molekül ağırlığı ve özelliklerinde kayıplara yol açmaktadır. Bu çalışmada geri dönüştürülmüş PBT (Gd. PBT) farklı yükleme oranındaki (%ağ. 0.5, 1, 1.5) polimerik bir zincir uzatıcı (Joncryl ADR 4368) ile çift vidalı ekstrüderde harmanlanmıştır. Örneklerin reolojik, mekanik ve termal özellikleri farklı karakterizasyon yöntemleri ile incelenmiştir. Reolojik sonuçlar zincir uzatıcının eklenmesiyle kopan zincirlerin tekrar bağlanarak Gd. PBT’nin viskoelastik özelliklerinin geliştiğini göstermiştir. Zincir uzatıcının Gd. PBT’nin özelliklerine olan önemli etkisi çekme testi sonuçlarından da doğrulanmıştır. Zincir uzatıcı içeren örneklerin elastik modül ve çekme dayanımları artış gösterirken, kopmadaki uzama değerleri zincir dallanmasına bağlı olarak düşmüştür. Zincir uzatıcının örneklerin dallanmış yapısına etkisi düşük kristalinite değerlerinden de gözlemlenmiştir. Termogravimetrik analiz zincir uzatıcının Gd. PBT’nin termal bozunma sıcaklığını arttırdığını göstermiştir. Zincir uzatıcı içeren örneklerin özelliklerindeki iyileşme artan zincir uzatıcı konsantrasyonu ile daha belirgin olmuştur.

Enhanced degradation and gas barrier of PBAT through composition design of aliphatic units

Aliphatic–aromatic copolyesters are indispensable in degradable plastics, but their properties are limited by low strength and modulus, and slow degradation rates in natural environment. Herein, we report a novel molecular design method to prepare poly(butylene adipate–co–diglycolate–co–terephthalate)(PBADT) copolyesters. In detail, the aromatic unit is fixed at 50% molar content of butylene terephthalate (BT) units, while the aliphatic units are consisted of butylene adipate (BA) and butylene diglycolate (BD) units. The PBADT copolyesters have melting temperatures higher than 130 °C and manifest rapid crystallization, high elastic modulus (>129 MPa) and satisfied ductile tensile behavior (>770%). Their gas barrier performance and hydrophilicity all increase with increasing BD units. Compared with PBAT, faster hydrolysis and seawater degradation are observed, which is explained by the more hydrophilic structure of diglycolate. This work provides insights and direction for the development of high-performance yet environmentally degradable alternatives to conventional biodegradable aliphatic–aromatic polyesters.

Poly(alkylene terephthalate)s: From current developments in synthetic strategies towards applications

• Applied synthesis strategies for poly(alkylene terephthalate)s (PATs) and their recent progress. • Observed trends in thermal and mechanical properties of PATs. • Overview of the applications of PATs. • Advances in sustainable monomer synthesis and PAT recycling. Poly(ethylene terephthalate) (PET), poly(trimethylene terephthalate) (PTT) and poly(butylene terephthalate) (PBT) are widely known and the mostly studied polymers belonging to the poly(alkylene terephthalate) (PAT) family, but there are many other polymers in this family of which the full potential has not yet been disclosed. Herein, we provide an overview of the state-of-the-art of this specific polyester type. In a first part, the various synthesis methods including melt polycondensation, solution polycondensation and ring-opening polymerisation together with their advantages and disadvantages are discussed. Next, an overview of the polymer properties and a comparison of their thermal and mechanical behaviour are provided. Due to the increasing interest in sustainability (e.g. production of PATs from bio-based monomers) and recycling aspects (e.g. depolymerisation), recent progress on PATs in these particular fields is also highlighted. Currently, PET, PTT and PBT are exploited in many applications while research is striving to broaden their application field.

Development of Circularly Recyclable Low Melting Temperature Bicomponent Fibers toward a Sustainable Nonwoven Application

Sustainable low melting temperature bicomponent polyester fibers that can be circularly recycled were developed. The potentially biobased poly(hexamethylene terephthalate) (PHT), acting as the low melting temperature sheath material in the designed bicomponent fibers, was synthesized in a pilot scale. The obtained PHT with an intrinsic viscosity of 0.47 dL/g showed suitable processability when it was processed together with a poly(butylene terephthalate) (PBT) core in a melt-spinning process of bicomponent fibers. Compared with the commercial low melting temperature terephthalate–isophthalate copolyester LMP-160, PHT showed superior mechanical properties according to DMA analysis. The low melting temperature bicomponent fibers with a ratio of the PBT core and PHT sheath at 70:30 were produced smoothly at 290 °C in a pilot melt-spinning line. Preliminary chemical recycling investigations by methanolysis revealed that PHT/PBT bicomponent fibers were completely depolymerized within 2 h at 200 °C, yielding pure terephthalate, which could be conveniently separated and recycled. This indicated the feasibility of circular recycling, which will greatly improve the sustainability of nonwovens thermally bonded by these new bicomponent fibers.

A Study of Recycled Poly(butylene terephthalate) and Low-Density Polyethylene Blend

A Study of Recycled Poly(butylene terephthalate) and Low-Density Polyethylene Blend

Microbial susceptibility of various polymers and evaluation of thermoplastic elastomers with antimicrobial additives

AbstractThe incursion of microbial growth on polymeric products can deteriorate their performance and lead to the development of undesirable staining and odors. A growing trend in the industry has aimed to reduce microbial populations on high‐touch surfaces via the use of antimicrobials to protect material aesthetics and durability or to prevent the spread of pathogenic microorganisms. In this study, a variety of plastic substrates (30 unique polymer compounds), including poly(acrylonitrile‐co‐butadiene‐co‐styrene), poly(butylene terephthalate), poly(etherimide), various thermoplastic elastomers (TPEs), poly(carbonates), and poly(amides), were screened for susceptibility to microbial attack using American Society for Testing and Materials (ASTM) G21 (fungi susceptibility), Japanese Industrial Standard (JIS) Z2801, and modified ASTM E1428‐15a (bacterial susceptibility) test standards. TPEs were determined to be most susceptible to microbial attack under the appropriate environmental conditions. Subsequent studies assessed the use of an antimicrobial additive, zinc pyrithione (ZPT), for potential efficacy in a variety of TPE blends for diverse target market applications. ZPT proved to be very effective in protecting TPEs, reducing Staphylococcus aureus and Escherichia coli populations by 99.9% or more in JIS Z2801 testing and inhibiting fungal growth (rating = 0) according to the ASTM G21 standard.

Evaluation of the morphological, rheological, dynamic mechanical and mechanical characteristics of compatibilized graphene oxide/poly(ethylene terephthalate)/poly(butylene terephthalate) nanocomposites

AbstractThe effectiveness of graphene oxide (GO) as reinforcement material and Joncryl as compatibilizing agent for poly(ethylene terephthalate) (PET)/poly(butylene terephthalate) (PBT) blend was evaluated. The blend and its nanocomposites were produced via melt extrusion and injection molding. Properties of the produced samples were explored by using Fourier transform infrared spectroscopy, scanning electron microscope (SEM), melt rheological measurements, dynamic mechanical analysis, and tensile test. While there was no interaction between GO and PET/PBT, the addition of Joncryl to nanocomposites resulted in possible ring‐opening reactions. SEM images showed that all nanocomposites were brittle and agglomerated while the PET/PBT matrix showed a ductile structure. The GO and Joncryl addition enhanced the viscoelastic properties of the PET/PBT. The tensile strength and elongation at break values of PET/PBT, decreased with the addition of GO, indicates weak interfacial adhesion. Joncryl has developed the mechanical properties by compatibilizing PET/PBT and GO.

Microstructure and properties of poly(butylene terephthalate)/poly(ethylene terephthalate) composites based on carbon nanotubes/graphene nanoplatelets hybrid filler systems

AbstractThis work describes the preparation of poly(butylene terephthalate) (PBT)/poly(ethylene terephthalate) (PET) composites using carbon nanotubes (CNTs)/graphene nanoplatelets (GNPs) hybrid fillers by melt blending process. The effects of CNTs/GNPs hybrid fillers on the thermal conductivity, electrical conductivity, electromagnetic interference shielding effectiveness (EMI SE) and mechanical properties of composites with varying CNTs/GNPs weight ratios were investigated. Scanning electron microscopy showed that the CNTs/GNPs hybrid fillers had better dispersion in PBT/PET matrix, they could effectively cooperate to build filler network structure. The excellent synergistic effects of hybrid fillers could significantly improve the mechanical properties and thermal conductivity. When adding 2 phr CNTs and 8 phr GNPs simultaneously, the thermal conductivity reached 0.84 W m−1 K−1 and Young's modulus was 1.2‐fold compared with PBT/PET blends. In addition, all hybrid composites with higher CNTs/GNPs weight ratios showed better electrical conductivity and EMI SE. The measurement of EMI SE and study of shielding mechanism indicated that absorption loss was the main mechanism for the attenuation of incident electromagnetic waves in hybrid composites over X‐band frequency.

Study on recycling of Poly(butylene Terephthalate) and Polypropylene blend

Poly (butylene terephthalate) (PBT) is a breakable plastic because its high modulus value makes it unsuitable for specific applications. Recycling PBT is even more complicated when the color is no longer the original milky white. This study takes R-PBT from the brush hair scraps and blends with 10% Polypropylene (PP). The results show that the mold continually adhered to is challenging to inject the sample 100% R-PBT. The surface of sample R-PBT / 10% PP has a good gloss and smooth texture, while there is a high shrinkage rate in sample 100% PP. The hardness of sample R-PBT / 10% PP is increased when adding PP. In addition, sample 100% R-PBT has a distinctive shape with tiny fibers, while model 100% PP has a flat surface. For the R-PBT / 10% PP sample, the microstructure has two distinct regions: PBT matrix and PP dispersed-droplets.

PEOT/PBT Polymeric Pastes to Fabricate Additive Manufactured Scaffolds for Tissue Engineering.

The advantages of additive manufactured scaffolds, as custom-shaped structures with a completely interconnected and accessible pore network from the micro- to the macroscale, are nowadays well established in tissue engineering. Pore volume and architecture can be designed in a controlled fashion, resulting in a modulation of scaffold’s mechanical properties and in an optimal nutrient perfusion determinant for cell survival. However, the success of an engineered tissue architecture is often linked to its surface properties as well. The aim of this study was to create a family of polymeric pastes comprised of poly(ethylene oxide therephthalate)/poly(butylene terephthalate) (PEOT/PBT) microspheres and of a second biocompatible polymeric phase acting as a binder. By combining microspheres with additive manufacturing technologies, we produced 3D scaffolds possessing a tailorable surface roughness, which resulted in improved cell adhesion and increased metabolic activity. Furthermore, these scaffolds may offer the potential to act as drug delivery systems to steer tissue regeneration.

Chitin Nanofibril Application in Tympanic Membrane Scaffolds to Modulate Inflammatory and Immune Response

Chitin nanofibrils (CNs) are an emerging bio-based nanomaterial. Due to nanometric size and high crystallinity, CNs lose the allergenic features of chitin and interestingly acquire anti-inflammatory activity. Here we investigate the possible advantageous use of CNs in tympanic membrane (TM) scaffolds, as they are usually implanted inside highly inflamed tissue environment due to underlying infectious pathologies. In this study, the applications of CNs in TM scaffolds were twofold. A nanocomposite was used, consisting of poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT) copolymer loaded with CN/polyethylene glycol (PEG) pre-composite at 50/50 (w/w %) weight ratio, and electrospun into fiber scaffolds, which were coated by CNs from crustacean or fungal sources via electrospray. The degradation behavior of the scaffolds was investigated during 4 months at 37 °C in an otitis-simulating fluid. In vitro tests were performed using cell types to mimic the eardrum, i.e., human mesenchymal stem cells (hMSCs) for connective, and human dermal keratinocytes (HaCaT cells) for epithelial tissues. HMSCs were able to colonize the scaffolds and produce collagen type I. The inflammatory response of HaCaT cells in contact with the CN-coated scaffolds was investigated, revealing a marked downregulation of the pro-inflammatory cytokines. CN-coated PEOT/PBT/(CN/PEG 50:50) scaffolds showed a significant indirect antimicrobial activity.