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Biodegradable films of poly(butylene adipate co-terephthalate) (PBAT)/thermoplastic starch (TPS)/beeswax have been prepared by solution casting method. Beeswax has been used as a hydrophobic content to improve the water barrier properties of the films. The prepared films have been characterized for tensile properties, morphology, water absorption, and water vapor permeability. Tensile strength of the films initially increases with the addition of beeswax and then decreases with increase in beeswax content. Tensile strength of film with 0.5 wt% of beeswax is about 213% greater than the film without beeswax. Water absorption percentage of films decreases gradually from 18.7% in film without beeswax to 0% with an increase in amount of beeswax, i.e., 0.5wt%, 1wt% and 2wt% due to the hydrophobicity of beeswax. Water vapor permeability of these films reduces upon increasing the amount of beeswax. [ABSTRACT FROM AUTHOR]

This paper aims to compare the performance of two Hytrel-like segmented copolymers: "classic" PBT-b-PTMG and fully bio-based PBF-b-PTMG, containing poly(butylene furanoate) as the rigid segment. The idea behind this research is to assess whether the sustainable copolymers can successfully replace those "classic" once at the thermoplastic elastomers' market. Two series of copolymers were synthesized under the same process parameters, had the same compositions, but differed in aromatic ring structure in terephthalate/furanoate unit. Furthermore, the materials were processed by injection moulding as typical Hytrel products. Then, the samples were subjected to extensive characterisation including NMR, GPC, FTIR, DSC, WAXS, DMTA, TGA techniques and mechanical tests with particular interest in the microstructure formed during processing and its effect on the copolymers' mechanical and elastic behaviour. The detailed analysis proved that PBF-b-PTMG and PBT-b-PTMG copolymers represent two kinds of materials with similar chemical structure, some features of thermoplastic elastomers, but evident differences in their physical properties. [ABSTRACT FROM AUTHOR]

Three blends of Poly(butylene 2,5-furandicarboxylate) (PBF) and Poly(lactic acid) (PLA) blends were modeled using molecular dynamics simulations, with PBF contents of 10%, 20%, and 30%, respectively. The study investigated the compatibilities of the blends, as well as the mechanical and gas barrier properties of the composite systems. The molecular dynamics simulation results show that: (1) PLA and PBF have good compatibility in the blend system; (2) the optimal toughness modification was achieved with a 20% PBF content, resulting in a 17.3% increase in toughness compared to pure PLA; (3) the barrier properties of the blend for O2, CO2, and N2 increased when increasing the PBF content. Compared to pure PLA, the diffusion coefficients of the O2, CO2, and N2 of the blends with 30% PBF decreased by 75%, 122%, and 188%, respectively. Our simulation results are in good agreement with the actual experimental results. [ABSTRACT FROM AUTHOR]

Aliphatic and aliphatic–aromatic polyesters are used widely in the food packaging field, which is very concerned about the volatile organic compound (VOC). Typical VOCs in poly (butylene succinate) (PBS) and poly (butylene adipate-co-terephthalate) (PBAT) are oligomers, especially cyclic esters, which were studied using GPC, MALDI-FTICR-MS and UPLC-FTICR-MS technique. Cyclic esters with repeating unit 2–8 were found in PBS; cyclic esters with repeating unit 1–10 (or more) were found in PBAT derived from three monomers with almost all possible random combinations. Cyclic esters with repeating unit 2–4 were the most abundant structures, but only cyclic esters with repeating unit 1–3 were found in the crystalline extracted from the recovered butanediol from the product line. Cyclic esters with repeating unit 1–3 can also be extracted from methanol at 70 °C for 1 h, and the content of linear oligomers increased with increasing temperature to 200 °C. But PBAT resin cannot be decomposed to monomers at 200 °C for 1 h in methanol without other additives. [ABSTRACT FROM AUTHOR]

Is report, the extraction process for highly nanocrystalline hydroxyapatite (HAp) by thermal decomposition of the femur bone of buffalo and its utilization as filler to produce nanocomposite with poly(butylene adipate‐co‐terephthalate) (PBAT). Advanced analytical techniques (such as X‐ray diffraction [XRD], Fourier transform infrared [FTIR] spectroscopy, and scanning electron microscopy [SEM]) are employed to study the structural, chemical, and morphological properties of the HAp. The XRD analyses reveal that the crystallite size of HAp particles significantly increases from 10 (at 600 °C) to 40 nm (at 1100 °C) on increasing the calcination temperature. The formation of agglomerates (having diameters ranging from 1.75 to 2.72 µm) with thin flake‐like crystals of the HAp is revealed by the SEM analysis. The biodegradation properties of the 3D printed PBAT/HAp nanocomposites are investigated by water absorption and tris‐buffer tests. The extent of water absorption of the nanocomposites is found to increase with the amount of the nanofiller. [ABSTRACT FROM AUTHOR]

Poly(butylene adipate-co-terephthalate) (PBAT), a polyester made of terephthalic acid (TPA), 1,4-butanediol, and adipic acid, is extensively utilized in plastic production and has accumulated globally as environmental waste. Biodegradation is an attractive strategy to manage PBAT, but an effective PBAT-degrading enzyme is required. Here, we demonstrate that cutinases are highly potent enzymes that can completely decompose PBAT films in 48 h. We further show that the engineered cutinases, by applying a double mutation strategy to render a more flexible substrate-binding pocket exhibit higher decomposition rates. Notably, these variants produce TPA as a major end-product, which is beneficial feature for the future recycling economy. The crystal structures of wild type and double mutation of a cutinase from Thermobifida fusca in complex with a substrate analogue are also solved, elucidating their substrate-binding modes. These structural and biochemical analyses enable us to propose the mechanism of cutinase-mediated PBAT degradation. Bio-degradation of poly(butylene adipate-co-terephthalate) is an attractive tactic but requires an effective hydrolytic enzyme. Here, the authors demonstrate that cutinases are highly potent PBAT-decomposing enzymes and their mechanism is proposed based on substrate-binding mode. [ABSTRACT FROM AUTHOR]

Electrospinning technology is famous for its simple preparation, and accurate and easy control of process parameters. It is widely used in ultrafine filtration membrane and biological tissue engineering support. Polycaprolactone (PCL) and poly(butylene succinate) (PBS) have good biocompatibility and are commonly used materials in electrospinning. In this study, the relationship between the electrospun sample, process parameters, and spinning solution of PCL/PBS blend system was systematically studied in an electrospinning experiment. The morphology characteristics, thermodynamic properties, and microstructure of the electrospun sample were screened by scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, and X-ray diffraction. The optimum conditions of electrospinning with high practical value were obtained. [ABSTRACT FROM AUTHOR]

Metal‐containing polymers represent an ever‐expanding frontier of material science. Of the numerous biocompatible ligands used to create a metallopolymer, piperazine‐containing polymers are still in their early development, even though piperazine is a common functional group in drug design and bioengineering scaffolding elements. We report the first synthesis and characterization (with NMR, IR, GPC, UV–vis spectroscopy, and thermal analysis) of two thermoplastic poly(alkyl piperazine succinate) diols with either propyl or hexyl alkane chains bridging the piperazines. These polyester diols were then chain extended with hexamethylene diisocyanate to create highly amorphous polyester urethane thermoplastic polymers. Ru(III) or Fe(III) was then successfully coordinated with these polymers, with approximately 30% of the bulk metallopolymer product becoming 250x the molecular weight of the non‐metal containing polymers. However, coordination of Fe(III), and to a lesser extent Ru(III), to these polypiperazines accelerated the hydrolysis of the polyester linkage in water over 15 days. Thus, these novel polymers are highly biodegradable with Fe(III) metallopolymers hydrolyzing faster than Ru(III) metallopolymers and poly(propyl piperazine succinate) polymers hydrolyzing faster than poly(hexyl piperazine succinate) polymers. [ABSTRACT FROM AUTHOR]

The formation of dense and complete conductive networks in the electromagnetic interference (EMI) shielding composite is the basis for its excellent EMI shielding performance. In this work, biodegradable poly (lactic acid)/poly (butylene succinate)/multi‐walled carbon nanotubes (PLA/PBS/MWCNTs) nanocomposites with segregated structures were successfully prepared via melt blending. Due to the successful preparation of segregated structures and the fact that MWCNTs were mainly dispersed in the PBS phase, an ultralow percolation value of 0.071 vol% was achieved in biodegradable PLA/PBS/MWCNTs nanocomposites. When the MWCNTs content is 0.499 vol%, the electrical conductivity of the PLA/PBS/MWCNTs nanocomposites with segregated structures is around 7.15 × 10−3 S/m, which is about 6 orders of magnitude higher than that of the PLA/PBS/MWCNTs nanocomposites with normal structures. When the MWCNTs content increased to 2.0 wt%, the average EMI shielding effectiveness (SE) of segregated structures remained stable at 27.56 dB, which can effectively block 99.82% of the microwave radiation. Furthermore, as suggested in the EMI shielding analysis, the EMI shielding of PLA/PBS/MWCNTs nanocomposites is mainly through absorption shielding, so there will be no secondary environmental pollution. This study provides a practical and universal method to prepare biodegradable conductive polymer composites with ultralow percolation threshold and excellent EMI SE. [ABSTRACT FROM AUTHOR]

The toughened poly(L-lactic acid)/poly(butylene succinate-butylene terephthalate) (PLLA/PBST) blend with enhanced melt strength and excellent low temperature toughness and strength was prepared by melt compounding through in situ compatibilization reaction in presence of multifunctional epoxy compound (ADR). The PLLA/PBST blend was an immiscible system, and the compatibility of the PLLA/PBST blend was improved after adding ADR. FTIR and GPC curves confirmed the formation of the PLLA-g-PBST copolymer, which improved the interfacial bonding of the blend and therefore the PLLA/PBST/ADR blend showed excellent melt strength and mechanical properties. For the PLLA/PBST/ADR blend with 70/30 PLLA/PBST content, the complex viscosity increased significantly with increasing ADR content. Moreover, the tensile strength, elongation at break and impact strength all increased obviously with increasing the ADR content. The elongation at break of the blend reached the maximum value of 392.7%, which was 93.2 times that of neat PLLA. And the impact strength of the blend reached the maximum value of 74.7 kJ/m2, which was 21.3 times that of neat PLLA. Interestingly, the PLLA/PBST/ADR blend exhibited excellent low-temperature toughness and strength. At −20 °C, the elongation at break of the PLLA/PBST/ADR blend was as high as 93.2%, and the impact strength reached 18.8 kJ/m2. Meanwhile, the tensile strength of the blend at low temperature was also high (64.7 MPa), which was beneficial to the application of PLA in the low temperature field. In addition, the PLLA/PBST/ADR blend maintaind good biodegradability, which was of great significance to the wide application of PLLA. [ABSTRACT FROM AUTHOR]

A kind of fully biodegradable poly (butylene adipate‐co‐terephthalate) (PBAT)/thermoplastic starch (TPS) blend is prepared by melt processing with epoxy‐terminated hyperbranched polymer (EHBP) as a modifier. The effect of EHBP on the performance of PBAT/TPS blends is investigated. The terminal epoxy group of EHBP can react with the hydroxyl and carboxyl groups of PBAT and TPS, which increases the compatibility of PBAT and TPS. Meanwhile, the formation of hydrogen bonds and chain entanglement increases the adhesion between PBAT and TPS, which improves the mechanical properties of the blends. When the content of EHBP is 3 phr, the elongation at break of TPS/PBAT/EHBP blends increases by 28.99% (from 260.32% to 335.79%) and the impact strength increases by 215.78% (from 9.38 to 29.62 kJ m−2). Scanning electron microscopy (SEM) images show that the compatibility of PBAT/TPS/EHBP blends gradually improves with the addition of EHBP. UV results show that the transparency of PBAT/TPS blends is greatly improved by the addition of EHBP, which also indicates the compatibility of PBAT and TPS is improved by the addition of EHBP. It provides an effective way to prepare PBAT blends with excellent properties through, an environmentally friendly and low‐cost processing method. [ABSTRACT FROM AUTHOR]

Poly(butylene succinate-co-terephthalate) (PBST) is an aliphatic–aromatic copolymer with excellent biodegradability and high flexibility, which can be used to replace traditional non-degradable polymer materials in various fields. However, its relatively low heat distortion temperature limits its applicability. Herein, poly(butylene succinate) (PBS) was blended with PBST to enhance the heat resistance of PBST. The chain extender ADR-4370F was used as a reactive compatibilizer to improve the compatibility between PBST and PBS. The hydrazide compound TMC-300 was use as a nucleating agent to improve the PBST/PBS blend's crystallization behavior and prepare a novel and eco-friendly PBST/PBS-based blend. The morphology of the cryo-fractured surfaces of PBST/PBS blends showed that the compatibility between PBST and PBS improved significantly upon adding ADR. Furthermore, compared to the PBST/PBS blend, Young's modulus, tensile strength, breaking strain, and breaking energy of the PBST/PBS/ADR blend showed great improvement. In addition, DSC results showed that the crystallization temperature (Tc) of PBST and PBS of PBST/PBS/ADR/TMC blend increased with increasing TMC content. WAXD results showed that the degree of crystallinity of PBST/PBS/ADR/TMC blends increased with incorporating PBS and TMC, increasing the Vicat softening temperature. Compared with neat PBST, the heat resistance of the PBST/PBS-based blend was improved. [ABSTRACT FROM AUTHOR]

The application efficiency of biodegradable polymers used in a natural environment requires improved resistance to ultraviolet (UV) photodegradation. In this report, 1,6-hexanediamine modified layered zinc phenylphosphonate (m-PPZn), utilized as a UV protection additive for acrylic acid-grafted poly(butylene carbonate-co-terephthalate) (g-PBCT), was successfully fabricated and compared to the solution mixing process. Experimental data of both wide-angle X-ray diffraction and transmission electron microscopy reveal that the g-PBCT polymer matrix was intercalated into the interlayer spacing of m-PPZn, which was approximately delaminated in the composite materials. The evolution of photodegradation behavior for g-PBCT/m-PPZn composites was identified using Fourier transform infrared spectroscopy and gel permeation chromatography after being artificially irradiated by a light source. The change of carboxyl group produced via photodegradation was used to show the enhanced UV protection ability of m-PPZn in the composite materials. All results indicate that the carbonyl index of the g-PBCT/m-PPZn composite materials after photodegradation for 4 weeks was extensively lower than that of the pure g-PBCT polymer matrix. These findings were also supported by the decrease in the molecular weight of g-PBCT after photodegradation for 4 weeks, from 20.76% to 8.21%, with the loading of 5 wt% m-PPZn content. Both observations were probably owing to the better UV reflection ability of m-PPZn. This investigation shows, through typical methodology, a significant advantage of fabricating the photodegradation stabilizer to enhance the UV photodegradation behavior of the biodegradable polymer using an m-PPZn compared to other UV stabilizer particles or additives. [ABSTRACT FROM AUTHOR]

Biodegradable polymers play a significant role in medical applications, especially internal devices because they can be broken down and absorbed into the body without producing harmful degradation products. In this study, biodegradable polylactic acid (PLA)-polyhydroxyalkanoate (PHA)-based nanocomposites with various PHA and nano-hydroxyapatite (nHAp) contents were prepared using solution casting method. Mechanical properties, microstructure, thermal stability, thermal properties, and in vitro degradation of the PLA-PHA-based composites were investigated. PLA-20PHA/5nHAp was shown to give the desired properties so it was selected to investigate electrospinnability at different applied high voltages. PLA-20PHA/5nHAp composite shows the highest improvement of tensile strength at 36.6 ± 0.7 MPa, while PLA-20PHA/10nHAp composite shows the highest thermal stability and in vitro degradation at 7.55% of weight loss after 56 days of immersion in PBS solution. The addition of PHA in PLA-PHA-based nanocomposites improved elongation at break, compared to the composite without PHA. PLA-20PHA/5nHAp solution was successfully fabricated into fibers by electrospinning. All obtained fibers showed smooth and continuous fibers without beads with diameters of 3.7 ± 0.9, 3.5 ± 1.2, and 2.1 ± 0.7 µm at applied high voltages of 15, 20, and 25 kV, respectively. [ABSTRACT FROM AUTHOR]

We have previously reported that sequence-controlled copolyesters such as poly((ethylene diglycolate) terephthalate) (poly(GEGT)) showed higher melting temperatures than those of the corresponding random copolymers and high biodegradability in seawater. In this study, to elucidate the effect of the diol component on their properties, a series of new sequence-controlled copolyesters composed of glycolic acid, 1,4-butanediol or 1,3-propanediol, and dicarboxylic acid units was studied. 1,4-Butylene diglycolate (GBG) and 1,3-trimethylene diglycolate (GPG) were prepared by the reactions of 1,4-dibromobutane or 1,3-dibromopropane with potassium glycolate, respectively. Polycondensation of GBG or GPG with various dicarboxylic acid chlorides produced a series of copolyesters. Terephthalic acid, 2,5-furandicarboxylic acid, and adipic acid were used as the dicarboxylic acid units. Among the copolyesters bearing terephthalate or 2,5-furandicarboxylate units, the melting temperatures (Tm) of the copolyesters containing 1,4-butanediol or 1,2-ethanediol units were substantially higher than those of the copolyester containing the 1,3-propanediol unit. Poly((1,4-butylene diglycolate) 2,5-furandicarboxylate) (poly(GBGF)) showed a Tm at 90 °C, while the corresponding random copolymer was reported to be amorphous. The glass-transition temperatures of the copolyesters decreased as the carbon number of the diol component increased. Poly(GBGF) was found to show higher biodegradability in seawater than that of poly(butylene 2,5-furandicarboxylate) (PBF). On the other hand, the hydrolysis of poly(GBGF) was suppressed in comparison with that of poly(glycolic acid). Thus, these sequence-controlled copolyesters have both improved biodegradability compared to PBF and lower hydrolyzability than PGA. [ABSTRACT FROM AUTHOR]

Poly(butylene sebacate-co-terephthalate) (PBSeT) has generated attention as a promising biopolymer for preparing bioplastics. However, there are limited studies on the synthesis of PBSeT, impeding its commercialization. Herein, with a view to addressing this challenge, biodegradable PBSeT was modified using solid state polymerization (SSP) with various ranges of time and temperature. The SSP used three different temperatures below the melting temperature of PBSeT. The polymerization degree of SSP was investigated using Fourier-transform infrared spectroscopy. The changes in the rheological properties of PBSeT after SSP were investigated using a rheometer and an Ubbelodhe viscometer. Differential scanning calorimetry and X-ray diffraction showed that the crystallinity of PBSeT was higher after SSP. The investigation revealed that after SSP for 40 min at 90 °C, PBSeT exhibited higher intrinsic viscosity (increased from 0.47 to 0.53 dL/g), crystallinity, and complex viscosity than PBSeT polymerized at other temperatures. However, a high SSP processing time resulted in a decrease in these values. In this experiment, SSP was most effectively performed in the temperature range closest to the melting temperature of PBSeT. This indicates that SSP could be a facile and rapid method for improving the crystallinity and thermal stability of synthesized PBSeT. [ABSTRACT FROM AUTHOR]

Highly biobased poly(butylene succinate-co-terephthalate) (PBST) with processing temperatures close to those of commodity polymers (160-180°C) and long-chain branched architectures (LCB) are synthesized by different strategies. Their rheological properties are investigated, in particular their melt strength properties. A two-step synthesis route is first proposed based on linear LCBs produced by polycondensation followed by reactive extrusion with an epoxy-based multifunctional agent Joncryl® at concentrations up to 2 wt%. A one-step synthesis strategy is also developed using glycerol as a branching agent, introduced at a low concentration (0.5 wt%) directly during the PBST polycondensation process. The molecular weights, LCB structures, and thermal properties are determined by triple detection size exclusion chromatography and differential scanning calorimetry. For PBSTs synthesized in two steps, gelation takes place simultaneously with the branching reactions. However, a concentration of Joncryl® close to 2 wt% is required to improve the melt strength properties, with strain hardening effects under elongation conditions. Interestingly, PBSTs synthesized by in-situ addition of glycerol show remarkable melt strength and a high melt stabilization process. Dynamic rheology investigations allow attributing these effects to statistical/homogeneous gel-free LCB architectures obtained during reactive extrusion without any additional post-processing. The effectiveness of approaches to easily improve the melt strength of highly biobased aliphatic-aromatic copolyesters (theoretical biobased content up to 85%) and to eliminate extrusion defects/instabilities in PBSTs is thus demonstrated, allowing the possibility of expanding the industrial application domains of these polymers in packaging and sustainable applications. [ABSTRACT FROM AUTHOR]

A biodegradable blend of PBAT—poly(butylene adipate-co-terephthalate)—and PLA—poly(lactic acid)—for blown film extrusion was modified with four multi-functional chain extending cross-linkers (CECL). The anisotropic morphology introduced during film blowing affects the degradation processes. Given that two CECL increased the melt flow rate (MFR) of tris(2,4-di-tert-butylphenyl)phosphite (V1) and 1,3-phenylenebisoxazoline (V2) and the other two reduced it (aromatic polycarbodiimide (V3) and poly(4,4-dicyclohexylmethanecarbodiimide) (V4)), their compost (bio-)disintegration behavior was investigated. It was significantly altered with respect to the unmodified reference blend (REF). The disintegration behavior at 30 and 60 °C was investigated by determining changes in mass, Young's moduli, tensile strengths, elongations at break and thermal properties. In order to quantify the disintegration behavior, the hole areas of blown films were evaluated after compost storage at 60 °C to calculate the kinetics of the time dependent degrees of disintegration. The kinetic model of disintegration provides two parameters: initiation time and disintegration time. They quantify the effects of the CECL on the disintegration behavior of the PBAT/PLA compound. Differential scanning calorimetry (DSC) revealed a pronounced annealing effect during storage in compost at 30 °C, as well as the occurrence of an additional step-like increase in the heat flow at 75 °C after storage at 60 °C. The disintegration consists of processes which affect amorphous and crystalline phase of PBAT in different manner that cannot be understood by a hydrolytic chain degradation only. Furthermore, gel permeation chromatography (GPC) revealed molecular degradation only at 60 °C for the REF and V1 after 7 days of compost storage. The observed losses of mass and cross-sectional area seem to be attributed more to mechanical decay than to molecular degradation for the given compost storage times. [ABSTRACT FROM AUTHOR]

A bioplastics film with excellent physical and barrier properties was prepared with Poly(butylene adipate-co-terephthalate) (PBAT), thermoplastic starch (TPS), and poly(propylene carbonate) (PPC). PBAT/TPS/PPC blend films were investigated through rheological measurements, tensile tests, scanning electron microscopy, mechanical dynamic analysis, and barrier properties. The content of PPC controlled the morphology and continuity development of the PBAT/TPS/PPC blend. With an increase in PPC, the TPS demonstrated better dispersion in the system, and the PBAT and PPC became the continuous phase. Compared with PBAT/TPS films, an increase in PPC led to a decrease in the water contact angle of the films, and water vapor permeability, oxygen permeability, and carbon dioxide permeability of PBAT/TPS/PPC films decreased by 53.1%, 74.4%, and 78.9%, respectively. The addition of PPC increased the dispersion of starch in the film and accelerated degradation of the film. PBAT/TPS/PPC films demonstrated good mechanical properties and excellent barrier properties, indicating that they have potential for use as degradable and cost-effective alternatives to traditional plastics in the packaging industry. [ABSTRACT FROM AUTHOR]

Four samples, including homopolymerized PP (PP-1), random impact copolymerized PP (PP-2), random impact copolymerized PP of ethylene-propylene (PP-3), and random impact copolymerized PP of ethylene-propylene-butylene (PP-4), which were prepared by 75 KG Spheripol process pilot plant using ZN104M as catalyst, were adopted to study the structure and performance, i.e., the influence of the different polypropylene molecular chain structures on the crystallization behavior of random impact copolymer polypropylene, and the changes in mechanical and optical performance due to the different aggregation structures of random impact copolymer polypropylene, and following results were achieved. Firstly, when ethylene-propylene rubber (EPR) and copolymerization monomers of ethylene and butylene were added in turn, the regularity of PP molecular chains decreased in different degree with the order of PP-1 > PP-2 > PP-3 > PP-4, and which further led to the same pattern for the crystallization peak temperature and the crystallinity. Secondly, half-crystallization time (T1/2) of the same cooling rate and the crystallization activation energy increased with the addition of EPR, ethylene and butylene. Crystallization activation energies were calculated to be 12.05 kJ mol−1, 12.09 kJ mol−1, 12.38 kJ mol−1 and 12.64 kJ mol−1 for PP-1, PP-2, PP-3 and PP-4, respectively. Last but the most importantly, the addition of EPR, ethylene and butylene would enhance the impact strength, but decrease the transmittance, whereas the haze changed little. Based on the theory between structure and performance, the reason that caused above results were analyzed. This work provided some guidance for the development of high-performance polypropylene used in identical fields. [ABSTRACT FROM AUTHOR]

Poly(butylene adipate-co-terephthalate) (PBAT) copolyester, which has good processing properties, is a new biodegradable synthetic polymer material in recent years. However, it is not satisfied with the mulch requirements because of its high cost and low mechanical strength. The mulch films of ternary blends including PBAT, polylactide (PLA), and poly(propylene carbonate) (PPC) are successfully prepared by extrusion blending and film blowing. The effect of different blow-up ratios (BUR) on the mechanical of mulch films was investigated. The 64/20/16 wt% PBAT/PPC/PLA mulch film of 3.1 BUR shows good mechanical properties. The tensile strength is as high as 43.0/37.6 MPa (MD/TD) while the elongation at break reaches 160/450% (MD/TD). The addition of PLA improves the strength of the mulch film, and the addition of PPC improves the barrier performance of the mulch film. It demonstrates that the PBAT, PPC, and PLA have partial compatibility from DMA and DSC analysis. After adding high-efficiency hindered amine light stabilizers, the mulch films have good light stability and their elongation at the break still exceeds 100% after 100 h of UV irradiation. [ABSTRACT FROM AUTHOR]

In this study, for the first time, we used cyclohexane dicarboxylic anhydride (CH) as the third monomer to terpolymerize with carbon dioxide (CO2) and propylene oxide (PO) under the catalysis of zinc glutarate (ZnGA). Incorporating cis‐CH (C‐CH) and trans‐CH (T‐CH) into poly(propylene carbonate) (PPC) improved the thermal and mechanical properties and increased the polymer molecular weight and yield. T‐CH showed better improvement than C‐CH because of its twist‐chair form. PPC‐CH containing 3% T‐CH exhibits the glass transition temperature (Tg) and maximum weight thermal decomposition temperature (Tmax) at 38.6 and 263°C, respectively, and shows the Young's modulus and tensile strength about 2.9 GPa and 40.5 MPa, respectively, which has comparable mechanical properties to commercial poly(butylene succinate), polypropylene, and high‐density polyethylene. PPC‐CH may form a novel method to recover CO2 in the form of polymers for various applications. [ABSTRACT FROM AUTHOR]

Poly(butylene adipate–butylene terephthalate) (PBAT) and poly(lactic acid) (PLA) biodegradable composites have been prepared by the melt‐blending method using a new methyl methacrylate and glycidyl methacrylate random copolymer (MG) as compatibilizer. The compatibilization reaction between the epoxy functional groups in MG and the carboxyl groups in PBAT and PLA resulted in the formation of branched PBAT‐co‐MG‐co‐PLA macromolecules and improved compatibility. The compatibilization effect induced higher glass transition temperature for PBAT and PLA. The addition of MG had little influence on the melting process of PBAT. However, the fine miscibility between PLA and MG inhibited cold crystallization and the following melting behavior of PLA. The compatibilization effect promoted the uniform dispersion and smaller particle size of the PLA phase, which enhanced the heterogeneous nucleation effect of PLA and induced higher crystallization temperature of PBAT. Dynamic rheological tests showed that PBAT/PLA/MG blends exhibited higher complex viscosity and modulus than PBAT and PBAT/PLA blend, proving the improved interfacial interaction and melt strength. Compared with the PBAT/PLA composite, PBAT/PLA/MG blends showed much better ductility and stiffness balance because of the compatibilization effect of MG. When MG concentration was 6 wt%, the blend achieved a maximum strain of 694% and tensile strength of 49.3 MPa, which were 1.8 and 4.3 times higher than those of the PBAT/PLA composite. © 2022 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

A new family of succinate‐based plasticizers, consisting of molecules with a linear alkyl chain capped with n‐alkyl succinates on both ends, was evaluated as potential bio‐based plasticizers for stiff polymers. The influence of the central and side alkyl chain lengths on the mechanical and thermal properties as well as the migration behavior of poly(vinyl chloride) (PVC)/plasticizer blends was evaluated. The central chain length had the greatest influence on plasticizer performance, with shorter chains leading to blends with higher stress at break and surface hardness, whereas long chains produced softer blends. An optimum chain central length of five carbon atoms was observed, with longer chains leading to reduced compatibility and exudation of the plasticizer at higher plasticizer concentrations. The entire family of plasticizers performed comparably or better than the commercial plasticizer di(2‐ethylhexyl) phthalate (DEHP) when incorporated into the blend at concentrations of 20–60 parts per hundred resin (phr). Overall, the succinate‐based plasticizers/PVC blends all exhibited equal or improved tensile properties (by up to 77%), surface hardness (reduced by up to 43%), glass transition temperature (reduced by up to 11°C), and migration into organic media (reduced by up to 38%) when compared with blends with DEHP at 40 phr. [ABSTRACT FROM AUTHOR]

The objective of this study is to include 5 wt% silane-treated starch (S-t-Starch) into biodegradable flexible poly(butylene adipate- co -terephthalate) (PBAT)/poly(3-hydroxybutyrate- co -3-hydroxyvalerate) (PHBV) blend matrix, which can facilitate superior barrier and balanced mechanical properties. With the intension of improving compatibilization between matrix and filler, starch (biological macromolecule) was efficiently treated with 15 wt% of 3-glycidoxypropyl trimethoxy silane (GPTMS), a coupling agent. Various analyses such as barrier, mechanical, thermal, surface morphology and rheological were performed using cast extruded PBAT/PHBV-based composite films. Comprehensive characterizations suggested that cast extruded PBAT/PHBV with 5 wt% S-t-Starch composites exhibited 91 and 82 % improvement in oxygen and water vapor barrier, respectively, compared to PBAT film. The increment in % crystallinity (as supported by DSC analysis) of PBAT/PHBV/5%S-t-Starch composite due to the silane component was one of the reasons for barrier improvement. The other reason was the improved interfacial adhesion between matrix and S-t-Starch particles (as supported by SEM analysis), which restricted the mobility of the polymer chains. The elongation at break (%EB) of the cast extruded PBAT/PHBV/5%Starch film was slightly improved from 536 to 542 % after silane treatment. Hence, the developed polymer composite in this research work can contribute to flexible packaging applications that require improved barrier properties. • Starch was treated with a coupling agent (3-glycidoxypropyl trimethoxy silane). • Silane-treated starch improved the barrier properties of PBAT/PHBV composites. • Higher %elongation (542 %) was observed for PBAT/PHBV/5%Silane-treated starch film. • Silane-treated starch enhanced the crystallization rate of PBAT/PHBV composites. • Silane-treated starch increased the complex viscosity of the PBAT/PHBV composite. [ABSTRACT FROM AUTHOR]

The raw material of polylactide (PLA) is lactic acid obtained by biological fermentation. PLA is the most promising degradable polymer to replace traditional plastics to address the pollution problems caused by their non-degradability. However, the application of PLA is hindered by its low softening temperature, easy hydrolysis, and poor toughness. Herein, the ternary composites with PLLA, PDLA and Poly (butylene adipate- co -terephthalate) (PBAT) were prepared by melt blending to balance its thermal stability, hydrolysis, and toughness. The effects of PBAT content (3 %, 6 %, 9 % and 12 %) and isothermal crystallization temperature on composite properties were fully investigated. The results show that the composite of stereo-complexed PLA (sc-PLA) with 6 % PBAT crystallized at 110 °C exhibits good comprehensive properties. Its vicat softening temperature (VST), mass loss rate under alkaline (pH = 12) and breaking elongation are 166 °C, 21.6 % and 4.40 %, respectively. Compared with the pure PLLA sample crystallized at same condition, the VST, mass loss rate and breaking elongation are 159 °C, 24.7 % and 3.76 % respectively, which increased by nearly 5 %, 13 % and 20 %. This indicates that this strategy is feasible to balance the heat resistance, hydrolysis resistance and toughness of PLA, while it sacrifices the tensile strength a little. This work provides a new way to modify and improve the PLA properties. Nonetheless, it is also necessary to coordinate the compatibility of PLA and PBAT. [ABSTRACT FROM AUTHOR]

Biodegradable polymers offer a promising alternative to the global plastic problems and especially in the last decade, to the microplastics problems. For the first time, samples of poly(butylene succinate) (PBSu) biocomposites containing 1, 2.5, and 5 wt% biochar (BC) were prepared by in situ polymerization via the two-stage melt polycondensation procedure. BC was used as a filler for the PBSu to improve its mechanical properties, thermal transitions, and biodegradability. The structure of the synthesized polymers was examined by 1H and 13C nuclear magnetic resonance (NMR) and X-Ray diffraction (XRD) along with an estimation of the molecular weights, while differential scanning calorimetry (DSC) and light flash analysis (LFA) were also employed to record the thermal transitions and evaluate the thermal conductivity, respectively. It was found that the amount of BC does not affect the molecular weight of PBSu biocomposites. The fine dispersion of BC, as well as the increase in BC content in the polymeric matrix, significantly improves the tensile and impact strengths. The DSC analysis results showed that BC facilitates the crystallization of PBSu biocomposites. Due to the latter, a mild and systematic increase in thermal diffusivity and conductivity was recorded indicating that BC is a conductive material. The molecular mobility of PBSu, local and segmental, does not change significantly in the biocomposites, whereas the BC seems to cause an increase in the overall dielectric permittivity. Finally, it was found that the enzymatic hydrolysis degradation rate of biocomposites increased with the increasing BC content. [ABSTRACT FROM AUTHOR]

Biocompatible and conductive polymer hydrogels are the subject of intensive research in the bioengineering field because of their use in bioelectronic devices and for the fabrication of electro-responsive tissues and drug delivery systems. In this study, we report the synthesis of conductive composite hydrogels consisting of a poly(N-isopropylacrylamide) (PNIPAM) matrix embedding carboxyl-functionalized multi-walled carbon nanotubes (MWCNT-COOH) using a two-step photopolymerization method. Thermo-responsive hydrogels with controlled hydrophilicity and conductivity were prepared by varying the carbon nanotube concentration in the range 0.5–3 wt%. The thermal response of the PNIPAM-based composite hydrogels was measured by differential scanning calorimetry with both ultrapure water and PBS solution as swelling liquid. Results show that the endothermic peak associated with the temperature-induced volume phase transition (VPT) shifts to higher temperatures upon increasing the concentration of the nanotubes, indicating that more energy is required to dissociate the hydrogen bonds of the polymer/filler network. In PBS solution, the swelling ratios and the VPT temperatures of the composite hydrogels are reduced because of salt-induced screening of the oppositely charged polymer/filler assembly, and the electrical resistivity decreases by a factor of 10 with respect to the water-swollen hydrogels. [ABSTRACT FROM AUTHOR]

The natural abundance, polymer stability, biodegradability, and natural antimicrobial properties of lignin open a wide range of potential applications aiming for sustainability. In this work, the effects of 1% (w/w) softwood kraft lignin nanoparticles (SLNPs) on the physicochemical properties of polybutylene succinate (PBS) composite films were investigated. Incorporation of SLNPs into neat PBS enhanced Td from 354.1 °C to 364.7 °C, determined through TGA, whereas Tg increased from −39.1 °C to −35.7 °C while no significant change was observed in Tm and crystallinity, analyzed through DSC. The tensile strength of neat PBS increased, to 35.6 MPa, when SLNPs were added to it. Oxygen and water vapor permeabilities of PBS with SLNPs decreased equating to enhanced barrier properties. The good interactions among SLNPs, thymol, and PBS matrix, and the high homogeneity of the resultant PBS composite films, were determined through FTIR and FE-SEM analyses. This work revealed that, among the PBS composite films tested, PBS + 1% SLNPs + 10% thymol showed the strongest microbial growth inhibition against Colletotrichum gloeosporioides and Lasiodiplodia theobromae, both in vitro, through a diffusion method assay, and in actual testing on active packaging of mango fruit (cultivar "Nam Dok Mai Si Thong"). SLNPs could be an attractive replacement for synthetic substances for enhancing polymer properties without compromising the biodegradability of the resultant material, and for providing antimicrobial functions for active packaging applications. [ABSTRACT FROM AUTHOR]

Biodegradable polymers have recently become popular; in particular, blends of poly(lactic acid) (PLA) and poly(butylene adipate terephthalate) (PBAT) have recently attracted significant attention due to their potential application in the packaging field. However, there is little information about the thermomechanical properties of these blends and especially the effect induced by the addition of PBAT on the shape memory properties of PLA. This work, therefore, aims at producing and investigating the microstructural, thermomechanical and shape memory properties of PLA/PBAT blends prepared by melt compounding. More specifically, PLA and PBAT were melt-blended in a wide range of relative concentrations (from 85/15 to 25/75 wt%). A microstructural investigation was carried out, evidencing the immiscibility and the low interfacial adhesion between the PLA and PBAT phases. The immiscibility was also confirmed by differential scanning calorimetry (DSC). A thermogravimetric analysis (TGA) revealed that the addition of PBAT slightly improved the thermal stability of PLA. The stiffness and strength of the blends decreased with the PBAT amount, while the elongation at break remained comparable to that of neat PLA up to a PBAT content of 45 wt%, while a significant increment in ductility was observed only for higher PBAT concentrations. The shape memory performance of PLA was impaired by the addition of PBAT, probably due to the low interfacial adhesion observed in the blends. These results constitute a basis for future research on these innovative biodegradable polymer blends, and their physical properties might be further enhanced by adding suitable compatibilizers. [ABSTRACT FROM AUTHOR]

Poly(lactide) (PLA) and poly(ethylene glycol) (PEG)-based hydrogels were prepared by mixing phosphate buffer saline (PBS, pH 7.4) solutions of four-arm (PEG-PLA)2-R-(PLA-PEG)2 enantiomerically pure copolymers having the opposite chirality of the poly(lactide) blocks. Dynamic Light Scattering, rheology measurements, and fluorescence spectroscopy suggested that, depending on the nature of the linker R, the gelation process followed rather different mechanisms. In all cases, mixing of equimolar amounts of the enantiomeric copolymers led to micellar aggregates with a stereocomplexed PLA core and a hydrophilic PEG corona. Yet, when R was an aliphatic heptamethylene unit, temperature-dependent reversible gelation was mainly induced by entanglements of PEG chains at concentrations higher than 5 wt.%. When R was a linker containing cationic amine groups, thermo-irreversible hydrogels were promptly generated at concentrations higher than 20 wt.%. In the latter case, stereocomplexation of the PLA blocks randomly distributed in micellar aggregates is proposed as the major determinant of the gelation process. [ABSTRACT FROM AUTHOR]

Reactive polyurethane hot melt adhesives (HMPURs) containing a blend of polyester and polycarbonate diols can typically exhibit balanced performance, such as bonding properties, tensile strength, and heat resistance. Two series of HMPURs made from poly 1,4-butylene adipate or sebacic acid (SeA)-based polyester diols with different molecular weights were prepared and investigated. Increasing the molecular weight of the SeA-based polyester diols was found to significantly improve their mechanical properties and lap shear strengths. Moreover, the HMPURs made from SeA-based polyester diol exhibited better performances than those made from poly 1,4-butylene adipate. Also, the HMPURs were more suitable for bonding on PC substrate. [ABSTRACT FROM AUTHOR]

The green sustainability of the plastic industry always gives impetus to develop the biobased and biodegradable polymers for substituting chemical products. In this study, aliphatic poly(ethylene succinate)‐based poly(ether ester)s (PES‐based PEE) were firstly explored via one pot/two‐component industrial melt polycondensation of succinic acid (SA) and ethylene glycol (EG) in the catalytic combination of titanium tetraisopropoxide (TTP) and methylsulfonic acid (MSA). Their thermal properties and mechanical behavior were analyzed in detail. Based on complementary properties of PES‐based PEEs and poly(lactic acid) (PLA) in the aspect of the flexibility and ductility, the copolymerization of poly(ethylene succinate)‐poly(diethylene glycol succinate) (PES‐PDES) with PLA with low molecular weight was further systematically elaborated and characterized. The results from differential scanning calorimeter showed all the copolymers with different LA contents were amorphous without the melting temperatures. Only one α relaxation revealed by DMA indicated PES‐PDES and PLA segments were random distribution and compatible. The monotonical decrease in glass transition temperatures (Tgs) hinted the mobility enhancement of the copolymers with increasing PES‐PDES contents. All the copolymers PES‐PDES‐PLAs exhibited relatively high thermal degradation temperature with T5% above 280°C. The mechanical properties and degradable behavior of the copolymers were significantly ameliorated by changing the composition fractions of PES‐PDES and PLA in the architecture. [ABSTRACT FROM AUTHOR]

Constructing the microcellular structure in the conductive polymer composites (CPCs) is a promising approach to improve the sensitivity and durability of the piezoresistive sensor. Selectively placing the conductive fillers, to form the segregated network between the polymer region, can effectively improve the electric performance of CPCs. However, few researches have focused on the influence of the polymer bead size on the segregated network and the large‐scale production of spherical polymer beads with low cost is still difficult to realize. Herein, plenty of regular‐shaped poly(butylene adipate‐co‐terephthalate) (PBAT) beads were manufactured through underwater pelletizing process, which was further coated with carbon nanotube (CNT) particles with the assistance of ball milling technology, and eventually the sensor was successfully fabricated through supercritical carbon dioxide (scCO2) bead foaming technology. The lightweight and flexible sensor exhibited the uniform cell structure with the mean cell size of 51.0 μm and cell density of 3.9 × 108 cells/cm3 when the pelletizing cutter speed was 2500 rpm and the foaming temperature was 117.5°C. And the conductivity of the sensor reached 6.5 S/m incorporated with 3 wt% CNT, which possessed high sensitivity, good stability and long‐term durability, attributed to its excellent microcellular structure and segregated conductive network. [ABSTRACT FROM AUTHOR]

In this study, the poly(lactic acid) (PLA)/poly(butylene adipate‐co‐terephthalate)(PBAT) blend is investigated to improve rheological and mechanical performances of PBAT based on rheological, mechanical, and thermal behavior analyses. The multi‐step mixing method is developed to fabricate the blend with non‐spherical morphology. In the multi‐step mixing method, blends with a wide composition range (25/75–75/25) are mixed with additional PBAT at a mixing temperature between the melting temperatures of PBAT and PLA to produce the PBAT blend embedded with non‐spherical PLA particles (10 wt%). The embedding of non‐spherical PLA particles in PBAT increases the resistance against deformation, resulting in strain hardening behavior and an increase in the yield strength as well as the tear resistance of the PBAT. The presence of stiff PLA particles enhances the crystallization behavior of PBAT, meaning that polymer chains may interpenetrate. The findings of this study suggest that the multi‐step mixing method is beneficial for embedding non‐spherical PLA particles into a PBAT matrix, which in turn facilitates the maintenance of good interfacial adhesion to increase the melt strength, yield strength, and tear resistance. [ABSTRACT FROM AUTHOR]

[Display omitted] • The economic feasibility and environmental impact of PBS from food waste were investigated. • Sensitivity analysis was conducted, and critical factors were investigated. • In this study, the minimum selling price of PBS was 3.5 $/kg. • In this study, GHG emission was 5.19 kg CO 2 -eq/kg of PBS. In this present study, the production of poly (butylene succinate) (PBS) from food waste was investigated and critical factors were evaluated. The economic feasibility of the process was investigated, as well as the minimum selling price (MSP) of PBS and sensitivity analysis of economic factors based on critical input parameters. 1,4-butanediol price and solvent usage in PBS purification significantly impacted economics during the process. In this process, the MSP of PBS was 3.5 $/kg. The Monte Carlo simulation technique was used to determine the uncertainty in the MSP of PBS. The plant's return on investment (ROI), payback period, internal rate of return (IRR), and net present value (NPV) were 15.79 %, 6.33 years, 16.48 %, and 58,879,000 USD, respectively. The environmental impact factors were evaluated. The results showed the GHG emission from the process was 5.19 kg CO 2 -eq/kg of PBS which is low than conventional PBS production. [ABSTRACT FROM AUTHOR]

The effect of styrene-ethylene/butylene-styrene block copolymer (SEBS) on the thermal degradation of polystyrene (PS)/high density polyethylene (HDPE) blends have been investigated. Polystyrene and (HDPE) are widely used thermoplastics, which have extensive application in everyday life. The main disadvantage of PS/PE systems is their poor miscibility which can be improved by adding compatibilizer. The blends were prepared by melt mixing in a twin screw extruder Haake Record 90. The behavior of the thermal degradation of PS/HDPE and PS/HDPE/SEBS blends has been investigated in inert nitrogen atmosphere by using thermogravimetric analysis (TGA) to obtain the degradation temperature and activation energy (E a ). The E a for the PS/HDPE blends as well as for the PS/HDPE/SEBS blends was determined by the isoconversional Kissinger–Akahira–Sunose (KAS) method. The results indicated that the HDPE enhance thermal properties of the blends. The addition of SEBS in PS/HDPE blends increased the E a in all blends. [ABSTRACT FROM AUTHOR]

To reduce thermal degradation of tea polyphenols (TP) in final active packaging materials, poly(butylene adipate- co -terephthalate) (PBAT), starch, plasticizer, and TP were directly synthesized into masterbatches by one-pot method in this study without pre-dispersion, and then blown into active films. TP interacted with starch through hydrogen bonds, with little interaction with PBAT. Barrier properties were improved by incorporating TP into the films, whereas mechanical properties slightly decreased. Blending starch into PBAT greatly accelerated the degradation of the film. And the incorporation of TP slowed down the short-term degradation of the starch/PBAT film, but accelerated the long-term degradation. The initial total polyphenol content in the active film was positively related to the TP loading, whereas the initial retention rate remained above 95 % regardless of TP loadings. The retention rate of TP in active films decreased with storage time, but it was still above 80 % after 12 months, with a favorable stability. TP-loaded films displayed efficient antioxidant and antimicrobial activities with strong dose dependence. The release of TP into food simulants was mainly induced by random diffusion, with little effect from polymer swelling. The short-term release kinetics was well described by Fick's second law. This work has demonstrated the feasibility of TP being incorporated into the active films with high retention through high-throughput fabrication, which provides formula and technical options for the industrial development of active packaging materials. [ABSTRACT FROM AUTHOR]

This work aimed to use the electrospinning technique to obtain PBAT/PLA polymer fibers, with the semiconductors rutile titanium dioxide (TiO2-R) and magnetite iron oxide (Fe3O4), in order to promote the photocatalytic degradation of environmental contaminants. The parameters used in the electrospinning process to obtain the fibers were distance from the needle to the collecting target of 12 cm, flow of 1 mL h−1 and voltage of 14 kV. The best mass ratio of semiconductors in the polymeric fiber was defined from a 22 experimental design, and the values obtained were 10% TiO2-R, 1% Fe3O4 at pH 7.0. Polymer fibers were characterized by Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and Fourier Transform Infrared (FTIR) techniques. SEM measurements indicated a reduction in fiber diameter after the incorporation of semiconductors; for the PBAT/PLA fiber, the average diameter was 0.9466 ± 0.2490 µm, and for the fiber with TiO2-R and Fe3O4 was 0.6706 ± 0.1447 µm. In the DSC, DRX, TGA and FTIR analyses, it was possible to identify the presence of TiO2-R and Fe3O4 in the fibers, as well as their interactions with polymers, demonstrating changes in the crystallinity and degradation temperature of the material. These fibers were tested against Reactive Red 195 dye, showing an efficiency of 64.0% within 24 h, showing promise for photocatalytic degradation of environmental contaminants. [ABSTRACT FROM AUTHOR]

Poly(butylene adipate-co-terephthalate) (PBAT), a biodegradable flexible, and tough polymer is herein used, for the first time, to encapsulate and protect isocyanate derivatives. Isocyanates are essential building blocks widely employed in the chemical industry for the production of high-performing materials. Microencapsulation of isocyanates eliminates the risks associated with their direct handling and protects them from moisture. In light of this, and having in mind eco-innovative products and sustainability, we present a straightforward process to encapsulate isophorone diisocyanate (IPDI) using this biodegradable polymer. Spherical and core-shell microcapsules (MCs) were produced by an emulsion system combined with the solvent evaporation method. The MCs present a regular surface, without holes or cracks, with a thin shell and high isocyanate loadings, up to 79 wt%. Additionally, the MCs showed very good isocyanate protection if not dispersed in organic or aqueous solutions. Effects of various process parameters were systematically studied, showing that a higher stirring speed (1000 rpm) and emulsifier amount (2.5 g), as well as a smaller PBAT amount (1.60 g), lead to smaller MCs and narrower size distribution. [ABSTRACT FROM AUTHOR]

To address the ever-increasing electromagnetic interference (EMI) pollution, a hybrid filler approach for novel composites was chosen, with a focus on EMI absorbance. Carbon nanofiller loading was limited to 0.6 vol.% in order to create a sustainable and affordable solution. Multiwall carbon nanotubes (MWCNT) and iron oxide (Fe3O4) nanoparticles were mixed in nine ratios from 0.1 to 0.6 vol.% and 8.0 to 12.0 vol.%, respectively. With the addition of surfactant, excellent particle dispersion was achieved (examined with SEM micrographs) in a bio-based and biodegradable poly(butylene succinate) (PBS) matrix. Hybrid design synergy was assessed for EMI shielding using dielectric spectroscopy in the microwave region and transmittance in the terahertz range. The shielding effectiveness (20–52 dB) was dominated by very high absorption at 30 GHz, while in the 0.1 to 1.0 THz range, transmittance was reduced by up to 6 orders of magnitude. Frequency-independent AC electrical conductivity (from 10−2 to 107 Hz) was reached upon adding 0.6 vol.% MWCNT and 10 vol.% Fe3O4, with a value of around 3.1 × 10−2 S/m. Electrical and thermal conductivity were mainly affected by the content of MWCNT filler. The thermal conductivity scaled with the filler content and reached the highest value of 0.309 W/(mK) at 25 °C with the loading of 0.6 vol.% MWCNT and 12 vol.% Fe3O4. The surface resistivity showed an incremental decrease with an increase in MWCNT loading and was almost unaffected by an increase in iron oxide loading. Thermal conductivity was almost independent of temperature in the measured range of 25 to 45 °C. The nanocomposites serve as biodegradable alternatives to commodity plastic-based materials and are promising in the field of electromagnetic applications, especially for EMI shielding. [ABSTRACT FROM AUTHOR]

Upconverting nanoparticles (UCNPs) are of particular interest in nanomedicine for in vivo deep-tissue optical cancer bioimaging due to their efficient cellular uptake dependent on polymer coating. In this study, particles, ca. 25 nm in diameter, were prepared by a high-temperature coprecipitation of lanthanide chlorides. To ensure optimal dispersion of UCNPs in aqueous milieu, they were coated with three different polymers containing reactive groups, i.e., poly(ethylene glycol)-alendronate (PEG-Ale), poly(N,N-dimethylacrylamide-co-2-aminoethylacrylamide)-alendronate (PDMA-Ale), and poly(methyl vinyl ether-co-maleic acid) (PMVEMA). All the particles were characterized by TEM, DLS, FTIR, and spectrofluorometer to determine the morphology, hydrodynamic size and ξ-potential, composition, and upconversion luminescence. The degradability/dissolution of UCNPs in water, PBS, DMEM, or artificial lysosomal fluid (ALF) was evaluated using an ion-selective electrochemical method and UV-Vis spectroscopy. The dissolution that was more pronounced in PBS at elevated temperatures was decelerated by polymer coatings. The dissolution in DMEM was relatively small, but much more pronounced in ALF. PMVEMA with multiple anchoring groups provided better protection against particle dissolution in PBS than PEG-Ale and PDMA-Ale polymers containing only one reactive group. However, the cytotoxicity of the particles depended not only on their ability to rapidly degrade, but also on the type of coating. According to MTT, neat UCNPs and UCNP@PMVEMA were toxic for both rat cells (C6) and rat mesenchymal stem cells (rMSCs), which was in contrast to the UCNP@Ale-PDMA particles that were biocompatible. On the other hand, both the cytotoxicity and uptake of the UCNP@Ale-PEG particles by C6 and rMSCs were low, according to MTT assay and ICP-MS, respectively. This was confirmed by a confocal microscopy, where the neat UCNPs were preferentially internalized by both cell types, followed by the UCNP@PMVEMA, UCNP@Ale-PDMA, and UCNP@Ale-PEG particles. This study provides guidance for the selection of a suitable nanoparticle coating with respect to future biomedical applications where specific behaviors (extracellular deposition vs. cell internalization) are expected. [ABSTRACT FROM AUTHOR]

Multifunctional drug delivery system that can treat bone infection and concurrently accelerate bone tissue regeneration is highly desirable. In this study, we developed a pH-responsive local drug carrier in which a core/shell microsphere consisting of a borate glass core and a mesoporous hydroxyapatite HA shell (BG-HA) was coated with glutaraldehyde-crosslinked chitosan (CS). At neutral pH, a negligible concentration of vancomycin was released from the BG-HA@CS microspheres. However, in an acidic environment, the pores on the HA shell were uncapped due to the swelling of CS, thus accelerating the drug release. The advantage of the BG-HA@CS was evidenced by comparing with HA@CS that was prepared by fully converting borate glass followed by CS coating. The dissolution of the unconverted borate glass core upon immersing in PBS led to an increase in the local pH. This change of pH regulated the swelling/de-swelling behaviours of CS, thereby realizing more sustained drug release. Furthermore, it revealed that the vancomycin-loaded BG-HA@CS provided highly effective antibacterial activity against S. aureus and E. coli , while the vancomycin-loaded HA@CS did not show inhibitory effect on E. coli. The results indicated that the BG-HA@CS would be a promising multifunctional delivery system that can achieve self-regulated drug release, control the acidic environment of bone infection sites and promote bone tissue regeneration. [ABSTRACT FROM AUTHOR]

Study on degradation behaviors of biodegradable poly(butylene adipate‐co‐terephthalate) (PBAT) blended with different compositions of thermoplastic starch (TPS) under soil burial and natural weathering environments is vital in order to predict the product service‐life and planning for in situ biodegradation after product disposal. In this article, different compositions of TPS (0%, 20%, 40%, 50%, and 60%) were compounded with PBAT using single screw extruder. The samples were characterized for their tensile properties, fractured surface morphology, water barrier and surface hydrophorbicity properties in order to investigate the effect of starch fractions in PBAT blends. The degradation behavior under natural weathering and soil burial conditions was also determined during the 9 months duration by observing the change of physical appearance, weight loss, surface morphology, chemical structural, and tensile properties. The findings showed that the addition of TPS (20%, 40%, 50%, and 60%) had led to a reduction in tensile strength (41.47%, 60.53%, 63.43%, and 68.53%), and reduction in elongation at break (42.92%, 92.1%, 92.23%, and 93.22%, respectively) and water barrier properties. The findings also showed that there were distinct degradation behavior under both conditions. Upon exposure to natural weathering, photodegradation and Norrish type I & II occurred whereas under the soil burial condition, hydrolytic, and enzymatic degradation take places. Sample with the highest starch contents underwent the highest weight loss and reduction in tensile properties under both environments. The findings in this study are useful in order to investigate the feasibility of PBAT/Tapioca starch blends for biodegradable plastic film for various industrial applications especially in packaging and agricultural mulch. [ABSTRACT FROM AUTHOR]

In this study, nanocomposite poly(lactic acid) and poly(butylene adipate‐co‐terephthalate) (PLA/PBAT) blends were prepared through polymer blending in the presence of multi‐functional epoxy as a compatibilizer that could react with epoxy group and terminated end group of two phases to increase interfacial adhesion between PLA and PBAT and improve the toughness of PLA. The effects of porous clay heterostructure from mixed CTAB:CTAC surfactant in the mole ratio of 1:2 (B1C2‐PCH) were also investigated. The elongation at break of the blends reached 38%, which was eight times that of neat PLA. The cryo‐fractured surface demonstrated the interfacial adhesion caused by the interaction of the epoxy group of the reactive compatibilizer with the terminal carboxyl and hydroxyl groups of PLA and PBAT. Moreover, PBAT reduced the crystallization rate and percent crystallinity of the PLA matrix and further decreased when compatibilizer was used. Alternatively, B1C2‐PCH accelerated the heterogeneous nucleation and crystallization of the nanocomposite films. After adding small amount of B1C2‐PCH, the nanocomposite films demonstrated excellent dielectric properties. Therefore, the improvement of PLA/PBAT nanocomposite blends are capable to be further developed as polymeric capacitor films. [ABSTRACT FROM AUTHOR]

To prepare poly (butylene succinate) (PBS)/cellulose nanocrystals (CNCs) with high performance and investigate the relationship between microstructure and properties, in this work, CNCs were firstly treated with ethyl succinyl chloride to improve their interfacial compatibility with PBS. Then melt spun processing was adopted to obtain PBS/CNC fibers, which were followed by heat stretching to further improve the orientation and mechanical properties of as-spun PBS fibers. The effects of modification of CNCs on chemical structure, their wettability as well as dispersion, thermal properties and mechanical properties were systematically investigated for the composite fibers. The dispersion, alignment of the CNCs and crystalline thermal behavior, and PBS chain orientation in the composite fibers were significantly influenced by the stretching treatment. The possible formation of multidimensional oriented superstructure including regularly arranged PBS shish kebab crystals, modified CNCs and oriented PBS chains has been suggested via SEM and SAXS in the composite fibers prepared at the high draw ratio. Significant improvement in tensile strength has been realized at the high draw ratio due to the enhanced orientation and dispersion of CNCs as well as the formation of multidimensional oriented superstructure. [ABSTRACT FROM AUTHOR]

Various products made from biodegradable polymers have been increasing rapidly in the market since the use of non-biodegradable materials has been banned, particularly for the disabled packaging materials. Burning remains the most popular method that is increasingly used in treating city wastes. The impact of these polymers on environmental during thermal degradation and combustion is an important issue for city waste management. In this work, the thermal degradation and combustion behaviours of the most popular synthetic biodegradable polymers in the market, poly(lactide acid) (PLA), poly(e-caprolactone) (PCL), poly(butylene succinate) (PBS), poly(butylene adipate-co-terephthalate) (PBAT) and polyhydroxyalkenoates (PHA), are investigated. Both isothermal and non-isothermal thermal decomposition in oxygen and nitrogen environment were studied using thermogravimetric analysis combining with differential scanning calorimeter and coupled with Fourier transform infrared spectroscopy and gas chromatograph/mass spectroscopy. The combustion behaviour was investigated by a combustion colorimeter. The study results show that thermal degradation temperatures are PCL > PBS > PLA > PBAT > PHA. The thermal decomposition of all the polyesters started from scission reaction (cis -elimination), and then a stereoselective cis -elimination, which resulted in the formation of trans -crotonic acid and its oligomers. They all decomposed into CO2 and water in excess oxygen environment above 800°C. Various chemical products with smaller molecules were detected under oxygen-free conditions, including oligomers and unsaturated carboxylic acid. The order of the total heat release of the materials from high to low is as follows: PHA > PCL > PBAT > PBS > PLA. The combustion values of these polyesters are lower than those of polyolefins; thus, they will not damage furnace used currently. The results provide some important and useful data for managing these new city waste. [ABSTRACT FROM AUTHOR]

Flame retardant poly(lactic acid)/poly(butylene adipate‐co‐ terephthalate) (PLA/PBAT) composites containing 9,10‐dihydro‐9‐oxa‐10‐ phosphaphenanthrene‐10‐oxide (DOPO) derivatives (phosphorus‐containing diol compound of DOPO‐HQ, and bis DOPO phosphonates of DIDOPO) were systematically and comparatively investigated. Results showed that the different structures of the two derivatives with reactable or soluble characteristics display different effects. DIDOPO endows a higher limiting oxygen index and a better UL‐94 rating for PLA/PBAT composites compared with DOPO‐HQ. Compared with that of PLA/PBAT, the peak heat release rate of PLA/PBAT/DIDOPO‐12.5 is 8.4% lower and that of PLA/PBAT/DOPO‐HQ‐12.5 is 30.6% lower. The flame retardant mechanism of the main gaseous and minor condensed phases is evident for the flame retardant PLA/PBAT composites. In comparison, DIDOPO displays a greater flame inhibition effect, and DOPO‐HQ shows better barrier and protective functions in PLA/PBAT composites. Besides, the elongation at break of the composites with DOPO‐HQ is slightly superior to that of PLA/PBAT/DIDOPO. After the introduction of flame retardant, the blends show dispersed particles with size reduction relative to those of PLA/PBAT. This work provides a guidance to design PLA composites with simultaneously improved flame retardancy and toughness. [ABSTRACT FROM AUTHOR]

This study focused on the development of a novel biocomposite material formed by a thermoplastic biodegradable polyester, poly(butylene succinate-co-adipate) (PBSA), and a carbonaceous filler as biochar (BC) derived by the pyrolysis of woody biomass waste. Composites with various BC contents (5, 10, 15, and 20 wt.%) were obtained by melt extrusion and investigated in terms of their processability, thermal, rheological, and mechanical properties. In all the composites, BC lowered melt viscosity, behaving as a lubricant, and enhancing composite extrudability and injection moulding at high temperatures up to 20 wt.% of biochar. While the use of biochar did not significantly change composite thermal stability, it increased its stiffness (Young modulus). Differential scanning calorimeter (DSC) revealed the presence of a second crystal phase induced by the filler addition. Furthermore, results suggest that biochar may form a particle network that hinders polymer chain disentanglement, reducing polymer flexibility. A biochar content of 10 wt.% was selected as the best trade-off concentration to improve the composite processability and cost competitiveness without compromising excessively the tensile properties. The findings support the use of biochar as a sustainable renewable filler and pigment for PBSA. Biochar is a suitable candidate to replace more traditional carbon black pigments for the production of biodegradable and inexpensive innovative PBSA composites with potential fertilizing properties to be used in agricultural applications. [ABSTRACT FROM AUTHOR]

Being aware of the global problem of plastic pollution, our society is claiming new bioplastics to replace conventional polymers. Balancing their mechanical performance is required to increase their presence in the market. Brittleness of bacterial poly(3-hydroxybutyrate- co -3-hydroxyvalerate) (PHBV) was attempted to be decreased by melt blending with flexible starch-based poly(butylene succinate- co -butylene adipate) (PBSA). An epoxy-functionalized chain extender was used to enhance interaction between both immiscible biopolyesters. Mechanical performance, morphology, rheology, and crystallization behavior of injection-molded PHBV-PBSA blends (70–30, 50–50, and 30–70 wt%) were assessed in the presence and absence of the chain extender. Crystallization of PHBV was hindered, which was reflected in the improvement of mechanical properties. When PBSA >50 %, the homogeneity of results increased within the same sample while for PHBV-PBSA 70–30 wt% the elongation was 45 % higher. During the flexural test, it changed from brittle to non-breakable. The additive did not change the type of morphology developed by each blend nor the toughening mechanisms, so impact strength was barely affected. However, it reduced the size of dispersed phase domains due to a viscosity change, improving their processability. The higher the PHBV in the blend, the higher the effect of the chain extender. [ABSTRACT FROM AUTHOR]