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PLA is widely known as biodegradable plastics whose further application in fields such as automotive and architectural is still constrained by its flammability and unsatisfactory crystallization properties. To address the aforementioned concerns, a novel biomass phosphonamide PDPA was synthesized with chemical structure confirmed by FTIR, NMR and elemental analysis tests. Immediately thereafter, PLA/PDPA composites were prepared by melting blending, with a focus on flame retardancy, crystallization properties and flame-retardant mechanism. As expected, PDPA efficiently enhanced both the flame retardancy and crystallization properties of PLA. Specifically, the PLA/4.0PDPA obtained UL-94 V-0 grade and the LOI value increased to 28.6 % with only 4 wt% PDPA added, which comes down to the superior free radical capture and dilution effect of PDPA in the vapor phase and the melting droplet effect. More appealingly, the crystallinity of PLA/4.0PDPA was significantly enhanced to 43.4 % from 2.5 % of PLA, and the shortest t 1/2 was 4 mins in the isothermal crystallization process due to the excellent heterogeneous nucleation of PDPA. Moreover, PLA/PDPA composites maintain almost the same mechanical performance as pure PLA. In brief, this work provides a green strategy for the preparation of PLA composites with excellent comprehensive performance and shows great potential in engineering materials., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Currently, it has long been considered a challenge to provide sustainable additives for polylactide (PLA) in green way to endow it excellent comprehensive properties. Given the flammability and unsatisfactory crystallization performance of PLA, a furan-based phosphate furfurylamine trimethylphosphate (FATMP) was synthesized from 2-furfurylamine and amino trimethylphosphonic acid by a simple hydration reaction, and the PLA/FATMP composites were prepared by melting blending process. The tensile performance, crystallization behaviors, flame retardancy, and flame-retardant mechanism received special attention. Results showed that the incorporation of only 3 wt% FATMP could indeed increase the LOI value of PLA from 19.8 to 27.3 %, and simultaneously acquired V-0 rating in the vertical burning test owing to the favorable synergistic effect between the vapor phase and the condensed phase. Additionally, the half-crystallization time of PLA was decreased from 12.4 to 5.1 mins with the addition of FATMP, which acted as a nucleating agent. More appealingly, the tensile performance of PLA/FATMP composites was also well maintained. In general, the PLA/FATMP composites we proposed could be promising candidates in application fields where favorable flame retardancy and crystallization ability are required., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The packaging industry demands improved eco-friendly materials with new and enhanced properties. In this context, bio-nanocomposite films with antimicrobial and UV-shielding properties based on modified cellulose nanocrystals/polycaprolactone (MCNC/PCL) were fabricated via solution casting method, and then food packaging simulation was carried out. CNCs were obtained by acid hydrolysis followed by successful functionalization with Quaternary ammonium surfactant, confirmed by FTIR, XPS, XRD, TEM, and DLS analyses. Furthermore, the morphological, physical, antibacterial, and food packaging properties of all prepared films were investigated. Results showed that the mechanical, UV blocking, barrier properties, and antibacterial activity of all composite films were remarkably improved. Particularly, the addition of 3 wt% MCNC increased the tensile strength and elongation at break by 27.5 % and 20.0 %, respectively. Moreover, the permeability of O2, CO2, and water vapor dramatically reduced by 97.6 %, 96.7 %, and 49.8% compared to the Neat PCL. Further, the UV-blocking properties of the composite films were significantly improved. The antimicrobial properties of MCNC/PCL films showed good antimicrobial properties against S. aureus. Finally, cherry packaged with 1 and 3 wt% MCNC films exhibited satisfactory freshness after 22 days of preservation. Overall, the fabricated PCL nanocomposite films can be utilized in the food packaging industry., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

3D-printing provides a feasible technique for realizing new materials into structural and intelligent parts. In this work, biomass furan-based polyesters poly (ethylene furanoate) (PEF), poly (trimethylene furanoate) (PTF), and poly (butylene furanoate) (PBF) were successfully synthesized in a 5 L reactor through the melt polycondensation process and fabricated into 3D-printing feedstocks. It was demonstrated that the three furan-based polyesters were additively-manufactured into complicated structures. Besides, the mechanical and thermal properties of furan-based polyesters could be tailored by the chain length of diol monomer. The mechanical performance of 3D-printed PEF, PTF and PBF were characterized and compared with commercial filaments. The tensile strength of PEF and PTF could reach 74.6 and 63.8 MPa respectively, which exhibited superior tensile property to poly(ether-ether-ketone) (PEEK), polyamide (PA) and polylactic acid (PLA). Meanwhile, the compression results demonstrated that the PEF and PTF possessed comparable energy absorption capacity with PEEK and PLA respectively, which indicated excellent mechanical properties of furan-based polyesters. It was interesting to find that the 3D-printed structures including solid cube, bionic flower and lattice structures were employed to prove that the PTF possessed excellent shape memory properties. Therefore, the proposed biomass furan-based polymers would offer more freedom in the field of 3D-printing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The reluctance of a polyester with high glass transition temperature ( T ) and mechanical properties to hydrolyze is a well-known fact, for instance, the high hydrolysis resistance of aromatic polyesters based on terephthalic acid and 2,5-furandicarboxylic acid (FDCA). The synthesis of polyesters that have a high g ) and mechanical properties to hydrolyze is a well-known fact, for instance, the high hydrolysis resistance of aromatic polyesters based on terephthalic acid and 2,5-furandicarboxylic acid (FDCA). The synthesis of polyesters that have a high T g (>100 °C) and a fast hydrolytic degradation quality at the same time is a valuable topic. Herein, a renewable rigid diester, N , N '- trans -1,4-cyclohexane-bis(pyrrolidone-4-methyl carboxylate) (CBPC), was obtained via Michael addition. CBPC was copolymerized with FDCA and ethylene glycol to prepare a series of copolyesters PEC x EF y with a high M n range of 75.2-109.2 °C which outdistanced the most biobased polyesters. The thermal stability of all PEC x EF y showed a T g range of 75.2-109.2 °C which outdistanced the most biobased polyesters. The thermal stability of all PEC x EF y remained unchanged with the introduction of CBPC. Moreover, PEC x EF y presented superior mechanical performances which were matching or exceeding those of commercial polyethylene terephthalate (PET) and polylactic acid (PLA). PEC x and hydrolyzation properties. The outstanding thermal and mechanical performances and hydrolysis of these copolyesters appear to be promising candidates for renewable alternatives to industrial petrochemical polyesters.y was stable in air but was able to undergo noticeable hydrolytic degradation, proving their enhanced degradability. And the regulation between CBPC and FDCA composition can be leveraged to adjust the degradation and environmental durability of PEC x EF y , up to practical applications. Computational studies systematically revealed the relationship between CBPC with a tricyclic structure and the improved T g and hydrolyzation properties. The outstanding thermal and mechanical performances and hydrolysis of these copolyesters appear to be promising candidates for renewable alternatives to industrial petrochemical polyesters.

A facile method in combination of "grafting from" and "end-functionalization" was developed for the synthesis of fluorescent highly branched poly(l-lactide)s (PLLA-COU) via ring opening polymerization (ROP) and esterification end-capping. These resulting PLLA-COU with four kinds of architectures, including linear, star, linear-comb, and star-comb structures, were subjected to characterization and application as fluorescent visible paclitaxel-loaded microspheres. The mutual effects of architecture and end-groups on thermal and fluorescence properties, enzymatic degradation, and drug release behaviors were focused. Contrast to linear and star PLLA-COU, two comb-shaped analogues demonstrated higher fluorescence quantum yield, faster drug release, and lower enzymatic degradation rate. All the fluorescent microspheres could maintain fluorescence traceability. The fluorescent PLLA-COU displayed negligible toxicity and good biocompatibility. This work highlights that the fluorescent highly branched poly(l-lactide)s are properties-tailored and used as fluorescent visible drug delivery systems (DDS) for potential theranostic applications.

In this work, we developed a facile end-functionalization method using hydroxylated coumarin to initiate the ring-opening polymerization of cyclic esters to synthesize a series of fluorescent biodegradable aliphatic polyesters with tailorable properties. The resulting fluorescent functionalized poly(l-lactide) (PLLA-COU), poly(ε-caprolactone) (PCL-COU) poly(δ-valerolactone) (PVL-COU) and poly(trimethylene carbonate) (PTMC-COU) were investigated to evaluate the dependence of fluorescence on the chemical structure and molecular weight of the materials. The differences in the electron withdrawing ability and the density of ester groups are responsible for the changes in the fluorescence quantum yield. Then, two representative biodegradable materials, namely, PLLA-COU and PCL-COU, were used to prepare fluorescent paclitaxel-loaded microspheres. During in vitro drug release, the release rate of the PCL-COU microspheres is dramatically faster than that of the PLLA-COU microspheres due to the difference in the material nature and their surface morphologies, possibly achieving a tunable degradation and release rate for the drug carriers. Fluorescent functionalized polyester microspheres can retain their fluorescence properties and emit bright blue light for fluorescence tracing during the degradation process. Biological evaluations showed that both fluorescent polyesters are devoid of any significant toxicity and have good biocompatibility. The results demonstrated that the obtained fluorescent polyesters are promising for use in traceable and controlled drug delivery with tunable drug release.

High-molecular-weight poly(ethylene brassylate-co-ε-caprolactone) copolyesters within a wide composition range were prepared via triphenyl bismuth catalyzed copolymerization of ethylene brassylate (EB) and ε-caprolactone (ε-CL) in bulk. Microstructural analysis of the resulting copolyesters demonstrated that the comonomer units were completely random distribution. DSC and WAXD recognized that the copolyesters cocrystallize within the lattices analogous to either of the parent homopolymers. It confirmed the isodimorphism behavior with a pseudo-eutectic point of melting temperatures as well as lattice spacings at 75 mol% ε-CL units. The crystal cell would be stretched in one dimension rather than expanding in both dimensions with the incorporation of comonomer units according to the result of WAXD. The mechanical properties of the copolyesters are well tunable by the composition, and its trend is consistent with the isodimorphism behavior, in particular, the maximum elongation at break over 2000% is located at the pseudo-eutectic point. The intralamellar shear occurred at the low tensile rate while both intralamellar shear and interlamellar shear occurred at high tensile rate. The copolymers exhibit excellent hydrolytic stability., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The aim of current study was to develop drug-loaded polymeric beads with intrinsic X-ray visibility as embolic agents, targeting for noninvasive intraoperative location and postoperative examination during chemoembolization therapy. To endow polymer with inherent radiopacity, 4,4'-isopropylidinedi-(2,6-diiodophenol) (IBPA) was firstly synthesized and employed as a contrast agent, and then a set of radiopaque iodinated poly(lactic acid)-polyurethanes (I-PLAUs) via chain extender method were synthesized and characterized. These I-PLAU copolymers possessed sufficient radiopacity, in vitro non-cytotoxicity with human adipose-derived stem cells, and in vivo biocompatibility and degradability in rabbit model via intramuscular implantation. Doxorubicin (DOX), as a chemotherapeutic agent, was further incorporated into I-PLAU beads via a double emulsification (W/O/W) method. For drug release, two ratios of DOX-loaded I-PLAU beads exhibited calibrated size (200-550μm), porous internal structure, good X-ray visibility, evenly drug loading as well as tunable drug release. A preliminary test on in vitro tumor cell toxicity demonstrated that the DOX-loaded I-PLAU beads performed efficient anti-tumor effect. This study highlights novel X-ray visible drug-loaded I-PLAU beads used as promising embolic agents for non-invasive in situ X-ray tracking and efficient chemotherapy, which could bring opportunities to the next generation of multifunctional embolic agents., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Biodegradable radiopaque iodinated poly(ester-urethane) (I-PU), consisting of poly(ε-caprolactone) (PCL) diol and iodinated bisphenol A (IBPA), has been successfully synthesized via a coupling reaction of PCL-diisocyanate and IBPA with varying compositions. The IBPA with four iodine atoms per molecule was applied as a chain extender to endow the I-PUs with intrinsic X-ray visibility. The chemical structure and molecular weights of I-PUs were characterized by Fourier transform infrared spectroscopy (FT-IR), proton-nuclear magnetic resonance, and gel permeation chromatography (GPC). The effects of IBPA on the physical properties of I-PUs were systematically studied by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and wide-angle X-ray diffraction (WAXD). The DSC results showed that the crystallization of PCL segments in I-PUs was restrained with increasing amount of IBPA, which was also confirmed by WAXD. In the X-radiography analysis, all the synthesized I-PUs exhibited high radiopacity compared with an aluminum wedge of equivalent thickness. Enzymatic degradation tests showed that the incorporation of IBPA prolonged the degradation of I-PUs and distinct mass loss and degradation happened in the third month. Basic cytocompatibility conducted using rat adipose-derived cells proved that all the I-PUs and their biodegradation products were nontoxic. The radiopaque I-PUs is expected to possess a significant advantage over the traditional polymer counterparts in some related biomedical fields., (Copyright © 2013 Wiley Periodicals, Inc.)

In this paper, DL-lactide, L-lactide and glycolide were synthesized from DL-lactic acid, L-lactic acid and glycolic acid respectively. A set of homopolymerizations of lactide with stannous octoate as initiator and laurly alcohol as co-initiator was carried out; a series of copolymers of poly (L-lactide-co-glycolide) (PLGA) were prepared via ring-opening polymerization of DL-lactide or L-lactide and glycolide with stannous octoate in high vacuum. The structure and properties of homopolymers and copolymers were characterized by 1H-NMR spectroscopy, differential scanning calorimetry and gel permeation chromatography. The in vitro degradation behavior of polylactide (PLA) and PLGA films in Hank's solution was investigated. The hydrolytic degradation of the PLA and PLGA was monitored by measuring the changes of inherent viscosity and weight loss of the resulting samples. The degradation rate of PLGA could be adjusted by changing the composition of the copolymer and be enhanced with the glycolide content increasing. It is suggested that the PLGA copolymer is a potential material as drug elusion coating on coronary stents.

The property profiles of ABA triblock copolymers can be precisely customized by changing the chemical structure of the components. The identification of the midblock is the key point in the development of PLLA-containing ABA triblock copolymers. Two kinds of unsaturated aliphatic polyesters, crystalline poly(cis-butene succinate) (PcBS) and amorphous poly(cis-butene glutarate) (PcBG) with dihydroxyl end groups were prepared by polycondensation reactions. Then, dihydroxyl-terminated PcBS and PcBG were used as macroinitiators to initiate ring opening of polymerization of L-lactide toward two series of fully biobased biodegradable PLLA-b-PcBS-b-PLLA and PLLA-b-PcBG-b-PLLA triblock copolymers with PLLA as hard end-blocks. The influences of the midblocks and the endblocks length on microstructure, thermal and tensile properties of the triblock copolymers were studied. Compared to homopolymer PLLA, all the triblock copolymers had a much higher elongation at break with lower tensile strength and tensile modulus, depending on the length of PLLA blocks. It was found that the amorphous PcBG midblock plays a greater role than the crystalline PcBS midblock in enhancing the tensile toughness of ABA triblock copolymers. PLLA-b-PcBG-b-PLLA composed of shorter PLLA hard block displayed typical elastomeric behavior without yield, which is a promising aliphatic polyester-based thermoplastic elastomer. The unsaturated carbon–carbon double bonds in these polyesters backbone provide a variety of opportunities for further modifications. [ABSTRACT FROM AUTHOR]

A series of triblock copolyesters were produced by ring-opening polymerization of l-lactide initiated by the dihydroxy-terminated poly(alkylene dodecanedioate)s as macroinitiators. The dihydroxy-terminated poly(alkylene dodecanedioate)s as low melting blocks were prepared by using 1,12-dodecanedioic acid and methyl substituted aliphatic diols. The influence of the different polyesters middle block on microstructure, thermal, crystallization and tensile properties of the triblock copolyesters was investigated. It was found that the poly(alkylene dodecanedioate)s containing methyl substitutions still exhibited crystallization and melting behavior, but the crystallization ability decreased when compared with linear poly(alkylene dodecanedioate). The diffraction peaks of soft and hard segments, measured by WAXD, showed a gentle trend after copolymerization. Through the TGA test, the results showed that thermal stability of the triblock polyesters was improved. Tensile tests exhibited that the elongation at break was improved significantly, with the highest elongation at break reaching 400%, while the tensile strength of triblock copolyesters decreased slightly compared with polylactide. The correlation between the middle block structures and their physical properties was explored and discussed. [ABSTRACT FROM AUTHOR]

Biobased odd–odd poly(propylene dicarboxylate)s, based on 1,3-propanediol and three odd diacids [i.e., glutaric acid (C5), pimelic acid (C7) or azelaic acid (C9)], have been synthesized and analyzed, in order to study the effect of chain length of aliphatic diacids on thermal properties. Crystallization and melting behaviors were investigated by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), temperature-modulated differential scanning calorimetry (TMDSC) and polarized optical microscope (POM). DSC results suggested that the crystallization ability increases with the increasing chain length. WAXD patterns of the three polyesters showed a similar crystal structure. In DSC heating curves after isothermal crystallization of the samples, three endothermic peaks for the polyesters at shorter chain length (C5, C7) and at most four endothermic peaks for longer-chain-length polyester (C9) were displayed, and the mechanism of the multiple melting phenomenon was discussed. One or two exothermic peaks can be seen for shorter (C7) or longer (C9) polyester in the non-reversible heat flows of TMDSC, respectively, which evidenced once or twice melting–recrystallization–remelting processes occurring during melting heating. Finally, POM observation indicated that the spherulitic growth rate increases with the increasing chain length. Besides, ring-banded structures were observed in short-chain-length (C5, C7) samples, but C9 aliphatic polyester. [ABSTRACT FROM AUTHOR]

Abstract In this work, a series of highly branched linear-comb random copolyesters of ε-caprolactone (CL) and δ-valerolactone (VL) with high molecular weight and narrow distribution in various compositions were successfully synthesized. The composition-dependent microstructure, thermal and mechanical properties, and enzymatic degradation behavior of the resulting copolyesters were investigated systematically. The cocrystallization behavior was observed for the highly branched linear-comb random CL/VL copolyesters over the entire composition range, and a pseudo-eutectic point of isodimorphism occurred at about 50 mol% VL incorporated in copolymer. The obtained copolymers displayed lower Young's modulus, yield strength, and breaking strength, but higher elongation at break. Furthermore, the copolymers presented much higher degradation rate during enzymatic degradation process in comparison with parent homopolymers. More importantly, it was found that both mechanical properties and degradation behavior showed a similar pseudo-eutectic behavior of isodimorphism. Consequently, the correlation among of isodimorphism, mechanical properties, and degradation behavior depending on composition is highly significant, and the physical properties and degradation rate of the isodimorphic copolyesters could be continuously tailored by the feedstocks. Graphical abstract Image 1 Highlights • Isodimorphism was observed for the highly branched linear-comb random CL/VL copolyesters. • Mechanical properties and degradation behavior showed a similar pseudo-eutectic behavior of isodimorphism. • Correlation among of isodimorphism, mechanical properties, and degradation behavior depending on composition. • Physical properties and degradation rate of isodimorphic copolyesters could be continuously tailored by feedstocks. [ABSTRACT FROM AUTHOR]

Four series of random aliphatic copolyesters derived from 1,6-hexanediol and different diacids were designed and synthesized to investigate the effect of chain length of aliphatic diacids on miscibility and competition of cocrystallization behavior. Isodimorphic behaviors were observed from DSC, WAXD and SAXS analyses for the four series of copolyesters. Crystal type transition point at isodimorphism depended on the chain length of comonomeric diacid units in copolyesters, which presented a crystallization competition effect between the two crystal types of parent homopolyesters. The comonomeric diacids with longer chain length had stronger competitive ability in controlling the cocrystallization even when they were present in a minor proportion. Then, the cocrystallization miscibility was qualitatively analyzed by WAXD and SAXS, and further quantificatively investigated by the defect Gibbs energy calculated from the Wendling-Suter method. For HS unit (hexamethylene succinate) incorporated into the crystal type of HL unit (HA, HSu, HSe or HD unit whose chain length of comonomeric diacids gradually lengthens compared to HS unit), the HL with longer chain length has better miscibility with the inserted HS unit. For HL unit squeezed into the crystal lattice of HS unit, HS unit has worse miscibility with the longer inserted HL unit. Moreover, the chain length inclusion-exclusion model on the basis of the Wendling and Suter theory is proposed to give an insight into the mechanism of how does the chain length of comonomers regulate the cocrystallization behavior. [ABSTRACT FROM AUTHOR]

Boric acid ( 1 , B(OH) 3 ) was investigated as metal-free biocatalyst for its activity towards the bulk ring-opening polymerization (ROP) of ε -caprolactone (CL) initiated by benzyl alcohol (BnOH). Moreover, other boric acid derivates such as phenylboronic acid ( 2 ), 2-thienylboronic acid ( 3 ), 2-furanylboronic acid ( 4 ) and 5-pyrimidinylboronic acid ( 5 ) were also used as acidic catalysts to synthesize poly( ε -caprolactone) (PCL), poly( δ -valerolactone) (PVL) and poly(trimethylene carbonate) (PTMC). The studies on the polymerization kinetics for all catalysts confirm that the reaction rates are first-order with respect to monomer and their catalytic activities follow the order 1 > 3 > 2 ≈ 4 > 5 . Furthermore, the block copolymerization of ε -caprolactone (CL) with δ -valerolactone (VL) and trimethylene carbonate (TMC) successfully proceeded by the sequential monomer addition to give PCL- b -PVL and PTMC- b -PCL copolymers, indicating the living nature of the present polymerization system. The end group analysis by 1 H NMR and MALDI-TOF MS measurements suggested that the benzyl moiety of initiator inserted into the synthesized polymeric chain. The existence of the interaction between the catalyst B(OH) 3 and the monomer CL supports that B(OH) 3 catalyzed ROP of CL preferred an activated monomer mechanism. A possible model for the initiation and propagation procedures of ROP of cyclic esters catalyzed by boric acid in the presence of benzyl alcohol was proposed. [ABSTRACT FROM AUTHOR]

Crystallization behavior and solid-state microstructure of poly(hexamethylene succinate) (PHS) and its phosphorus-containing copolyesters with bulky pendent group (DDP) have been investigated. The molecular weight, chemical structure and composition of the copolyesters were characterized and confirmed by GPC, 1 H and 31 P NMR. WAXD results suggest that the bulky DDP comonomer units in the copolyesters are noncrystallizable and are extruded from the crystal lattice of PHS. POM observations indicate that the spherulitic morphology becomes irregular and blurry with an increase of the DDP content. The kinetics analysis of isothermal crystallization shows that the crystallization of the copolyesters is retarded by the presence of the bulky DDP comonomer units. The observed crystallization and melting temperatures of the copolyesters are progressively depressed with the increase of DDP. SAXS quantitative analysis provides a proof that the significant increase in the long period of the copolyesters mainly arises from the increase in the amorphous layer, because the thickness of the lamellar increases slightly. A model of the lamellar crystal structure of the copolyester is proposed for its depression of the equilibrium melting temperature. [ABSTRACT FROM AUTHOR]

Novel biodegradable poly(butylene succinate) (PBS) copolyesters containing phosphors flame-retardant groups were synthesized by melt-polycondensation from succinic acid and 9,10-dihydro-10-[2,3-di(hydroxycarbonyl)propyl]-10-phosphaphenanthrene-10-oxide (DDP) with 1,4-butanediol. In order to analyze the effects of the third monomer (DDP) on the relative properties of PBS, the composition, crystal structure, crystallization behavior, multiple melting behavior, and spherulitic morphology of the copolyesters were investigated by H-NMR, WAXD, DSC, and POM, respectively. WAXD data revealed that the crystal structure of PBS was not affected by DDP. The overall crystallization kinetic showed that the crystallization of PBS was retarded with the introduction of DDP, especially when the DDP content exceeds 7.5 mol%, which may result from the stereo-hindrance of DDP unit. Furthermore, crystallization temperature ( T), crystallization enthalpy (Δ H), melting temperature ( T), and crystallinity ( X) of PBS copolyesters also decreased apparently with the increase in DDP contents. Also, the equilibrium melting temperature ( T) obtained from Hoffman-Weeks analysis decreased, indicating that the regularity of PBS chain segments was reduced probably due to the diluent effect of the specific chain structure of DDP. All spherulites showed the ring-banded extinction patterns, which implied that phosphorus-containing (DDP) segment did not change the growth mechanism of PBS crystals. [ABSTRACT FROM AUTHOR]

Biodegradable radiopaque iodinated polyurethanes (I-PUs) based on poly(ε-caprolactone) diol (PCL) as soft segment have been synthesized using 4,4′-isopropylidene-(2,6-diiodophenol) (IBPA) as chain extender. In order to elucidate the effect of iodinated chain extender on degradation properties of I-PUs, a control polyurethane with bisphenol A as chain extender was also synthesized. The enzymatic degradation study of these I-PUs was carried out using phosphate-buffered solution (pH 7.4) at 37 °C. The mass loss, surface morphology, iodine content, radiopacity, hydrophilicity and thermal properties of the samples during degradation were characterized with scanning electron microscopy (SEM), energy-dispersive X-ray detector (EDX), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and static contact angle. Results of enzymatic degradation during 3 months indicated that the incorporation of iodinated chain extender greatly hindered the in vitro degradation of I-PUs compared with the control PU-C sample. The reason for the retarded degradation was attributed to the bulky iodine atoms on IBPA chain extender with steric hindrance, which decreased the surface hydrophilicity of I-PUs and slowed water/lipase diffusion rate. Moreover, the radiopacity of I-PUs does not sharply attenuate after long-time degradation, which is useful for interventional biomedical applications. [ABSTRACT FROM AUTHOR]

In this article, two series of ABA triblock copolyesters composed of poly(l -lactide) A hard blocks and odd-odd aliphatic polyesters as B soft midblock were prepared and compared by various techniques. The results showed that the block structures could be formed without any detectable transesterification, and the composition and molecular weight of the triblock copolyesters could be well controlled by adjusting the feeding ratio of l -lactide monomer to the polyester macroinitiator. It was found that the thermal properties, crystal structure, and spherulitic morphology of the triblock copolyesters depended on the composition and block length. The impact of amorphous and crystalline midblocks on the mechanical properties was compared and discussed. The triblock copolyesters composed of crystalline midblock showed similar ultimate stress and elongation, but higher tensile modulus and yield stress, in comparison with analogous containing amorphous midblock. The triblock copolyester composed of short PLLA hard block and amorphous aliphatic polyester soft midblock displayed typical elastomeric behavior without yield, which is a promising aliphatic polyester thermoplastic elastomer. Image 1 • Aliphatic polyester thermoplastic elastomers have been successfully synthesized. • Aliphatic polyesters were used as B soft midblock of PLLA triblock copolymers. • Impact of amorphous and crystalline midblocks on the mechanical properties has been compared. • The elongation at break up to 676% illustrates well toughening modification. [ABSTRACT FROM AUTHOR]

The effect of sequence on copolymer properties is rarely studied, especially the degradation behavior of the biomaterials. A series of linear-comb block, gradient, random copolymers were successfully achieved using hydroxylated polybutadiene as the macroinitiator by simple ring-opening polymerization of l-lactide (l-LA) and 1,3-trimethylene carbonate (TMC). The hydrolytic degradation behaviors of the copolymers were systemically evaluated by using nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), differential scanning calorimeter (DSC), and scanning electron microscopy (SEM) to illustrate the influences of comonomer compositions and sequence structures. The linear-comb block copolymers (lcP(TMC-b-LLA)) with different compositions had different degradation rates, which increased with l-LA content. Thermal property changes were observed with decreased Tm and increased ΔHm in all block copolymers during the degradation. To combine different sequence structures, unique degradation behaviors were observed for the linear-comb block, gradient and random copolymers even with similar comonomer composition. The degradation rates of linear-comb PLLA-gradient-PTMC (lcP(LLA-grad-TMC)) and linear-comb PLLA-random-PTMC (lcP(LLA-ran-TMC)) were accelerated due to the loss of regularity and crystallinity, resulting in a remarkable decrease on weight retention and molar mass. The hydrolysis degradation rate increased in the order lcP(TMC-b-LLA), lcP(LLA-ran-TMC), lcP(LLA-grad-TMC). Therefore, the hydrolytic degradation behavior of comb-like graft copolymers depends on both the compositions and the sequences dramatically. [ABSTRACT FROM AUTHOR]

Three series of even-odd aliphatic copolyesters, poly(hexamethylene gluarate-co-hexamethylene pimelate) (PHGP), poly(hexamethylene pimelate-co-hexamethylene azelate) (PHPA), and poly(hexamethylene gluarate-co-hexamethylene azelate) (PHGA), were firstly synthesized derived from even diol of 1,6-hexanediol with odd diacids of glutaric acid, pimelic acid or azelaic acid, respectively. Then, their cocrystallization behaviors were systematically investigated by DSC, WAXD, and POM techniques. It is found that both PHGP and PHPA showed isodimorphism with a characteristic eutectic behavior observed from the plot of melting point versus composition, however, PHGA exhibited strict isomorphism in the whole composition range without a eutectic point. WAXD studies also confirmed the unique isodimorphism and isomorphism behaviors for even-odd copolyesters. The only slight change of the methylene number in alkyl unit of comonomers could generate so large difference in crystallization behavior, which exhibits unique physicochemical properties and structure–properties correlations in such even-odd copolyesters. Furthermore, the difference in cocrystallization miscibility effect of comonomers was analyzed by thermodynamics based on the defect Gibbs energy calculated from Wendling-Suter model. For PHGP and PHPA, the comonomer units have better miscibility in the case of the incorporation of shorter unit into the longer unit crystal than the opposite case. By contrast, in the case of PHGA, the HG and HA units are perfectly miscible in a same crystal lattice with only a little difference in crystal cell dimensions due to the identity of chain conformation of HG and HA units during packing into the crystal lattice. Finally, a model of crystal lattice structure of copolyesters was proposed to better understand the difference in cocrystallization miscibility effect of comonomers between isodimorphism and isomorphism. [ABSTRACT FROM AUTHOR]

• Linear unsaturated polyesters with high molecular weight were prepared based on the biobased cis -2-butene-1, 4-diol. • The polyesters show excellent thermomechanical property, satisfactory crystalline property and broad processing window. • These biobased polyesters were functionalized with hydroxyl groups by thiol-ene click reaction. This work describes the synthesis, thermomechanical properties, and functionalization of unsaturated polyesters based on biobased cis -2-butene-1, 4-diol (c B). Under an optimized experimental process, polyesters were synthesized by melt polycondensation employing c B and α, ω-diacids with even chain length. The high molecular weight of M w up to79.5 kDa was achieved for the poly(cis -butene dicarboxylate)s (P c BX), and meanwhile without isomerization or branching side reactions occurring in the polycondensation. Hence, c B was a suitable unsaturated diol for direct usage in the preparation of linear unsaturated polyester with high molecular mass. The result of mechanical properties indicated that c B outperforms 1, 4-butanediol in regard to enhancing the mechanical property of polyesters. Satisfactory thermal and crystal performances, broad processing window, as well as excellent mechanical properties were presented for P c BX, indicating that these synthetic biobased polyesters were promising candidates for replacing petroleum-based polyesters in practical application. Furthermore, an attempt was made to incorporate the functional group of hydroxyls in the backbones through "click reaction", and the existence of free hydroxyls on the surface of P c BX results in their greatly improved hydrophilicity. The inserted hydroxyls greatly accelerated the degradation rate of polyesters. Overall, this paper not only offers a straightforward method for the preparation of high molecular mass unsaturated polyesters with adjustable performances, but also presents the potential of functionalization for a broad range of applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Trans -2-butene-1,4-diol (t B), a renewable unsaturated monomer prepared from erythritol, is a promising building block for future biobased unsaturated polyesters. Herein, a series of biobased unsaturated polyesters based on t B and eight linear α, ω-diacids was explored by melt-polycondensation. Under the optimized reaction conditions, the alkene bonds of t B were intact in the polyester backbones with no isomerization or saturation side reactions taking place during the polymer synthesis even without a radical quencher adding. Surprisingly, the synthetic unsaturated polyesters reached high weight average molecular weight (M w) up to 93.0 kDa. These results indicated that t B was an ideal unsaturated monomer used for the synthesis of biobased unsaturated polyesters with well-defined structure. Moreover, the structure–property relationships of the unsaturated polyesters were discussed via studying the effect of chain length on crystalline and thermo-mechanical properties. The result of tensile test manifested that t B performed better than 1, 4-butanediol in improving the tensile stress of polyesters. Among the synthetic polyesters, poly(trans -butene suberate)(P t BSu), poly(trans -butene sebacate) (P t BSe), and poly(trans -butene dodecanedioate) (P t BDo) gave T m of 61.2−78.5 °C, satisfactory crystalline property, and exhibited comparable or even better tensile properties compared with most industrial aliphatic polyesters. Overall, t B was a promising candidate for replacing petroleum-based monomers for the preparation of unsaturated polyesters with superior thermomechanical properties. [Display omitted] • High molecular-weight unsaturated polyesters were prepared based on the biobased trans -2-butene-1, 4-diol. • The polyesters show excellent thermomechanical property, satisfactory crystalline property and broad processing window. • The physical properties of the polyesters could be effectively regulated by changing the chain length of diacids. [ABSTRACT FROM AUTHOR]

The design and development of high-performance marine-degradable plastics have long been considered a superior strategy to address marine plastic pollution. To achieve a balance between rapid marine degradability and high performance of polyester plastics, this work designed two series of poly(butylene oxalate) (PBOx) copolymers with intrinsic hydrolysis ability using poly(ethylene oxalate) (PEOx) and poly(glycolic acid) (PGA) as promotion building blocks. The synthesis process, crystallization properties, barrier performance, and mechanical properties of copolymers were comparatively investigated. Additionally, the marine degradability of copolymers received specific focus. The theoretical calculation demonstrated that the introduction of promotion blocks reduced the hydrolysis energy barrier of the copolymers. In general, the results revealed the advantages of PBEOx copolymer in satisfying practicality and better regulating marine degradability. The high gas barrier performance, suitable thermal properties, tunable mechanical properties, and rapid marine degradability endow the copolymer as a promising candidate toward sustainable and marine-degradable plastics. [Display omitted] • A macromolecular design strategy toward the PBOx copolymers with the rapid intrinsic marine degradability. • High molecular weight, tunable mechanical performance, and high barrier properties depend on copolymer composition. • DFT calculation demonstrated that the mechanism of marine degradability accelerated by the introduction of EOx and GA units. • The rapid marine degradable PBOx copolymers provide a possible solution to marine plastic pollution. [ABSTRACT FROM AUTHOR]

• Utilizing a renewable tricyclic diester to prepare biobased polyesters with high molecular weight. • The tricyclic diester imparts the high glass transition temperature (over 100°C) to the resulting polyesters. • The polyesters exhibit superior mechanical properties than those of mainstream commercial polyesters. • The polyesters in air are stable but are able to undergo noticeable hydrolytic degradability. The development of biobased polyesters which concurrently achieve high‐performance and hydrolyzability, is a significant challenge. Here N,N′-trans-1,4-cyclohexane-bis(pyrrolidone-4-methyl carboxylate) (CBPC), a tricyclic diester, was prepared by Michael addition-cyclization from renewable feedstocks. Single-crystal X-ray revealed an unfolded skeleton of CBPC, in which two pyrrolidones symmetrically disposed in non-planar space around the cyclohexane. CBPC exhibited a high reactivity to be polymerized with various diols to generate biobased polyesters with high number-average molecular weight over 40 kDa. The tricyclic structure imparts the high glass transition temperature (T g) (over 100°C), tough mechanical properties (tensile strength up to 56.8 MPa) as well as noticeable hydrolytic degradation to the resulting polyesters, which exhibit great potential to compete with commercial polyesters of polyethylene terephthalate (PET), polylactic acid (PLA) and polybutylene terephthalate (PBT). The hydrolytic pathway and reactivity site of the polyesters were further elucidated by the theoretical calculation. Note that PBT, PET and PLA are extremely reluctant to hydrolyzation, a higher sensitivity to hydrolysis is desired for high-performance polyester to reduce environmental impact. Overall, this work addresses some critical requirements for high-property polyesters which concurrently achieve high T g values, tough mechanical properties, wide process windows, and hydrolysis quality. [Display omitted] [ABSTRACT FROM AUTHOR]

Lignin is an important biomass resource to replace petrochemical industry for carbon neutrality. However, it is challenged by unyielding the trade-off between activity and selectivity owing to the chemical complexity and inherent heterogeneity of lignin biomacromolecule. Herein, we report that copper nanomaterial (CuO/C) derived from metal-organic framework (HKUST-1) could effectively catalytic hydrogenolysis of herbaceous plants into monomeric phenols (up to 29.5 wt%) through a lignin-first strategy, affording methyl 3-(4-hydroxyphenyl) propionate (1-H) and methyl 3-(4-hydroxy-3-methoxyphenyl) propionate (2-G) as the main monophenols with high selectivity of 31.9% and 17.3%. Moreover, we proposed two synthetic routes based on the purification and functionalization of those two compounds (1-H and 2-G) to synthesis 3-(4-carboxyphenyl) propionic acid and functional polyesters. Subsequent studies revealed that the temperature of 50% mass loss of the two polyesters reached 430–440 °C, indicating their robust thermal stability; while the DSC curves showed the difference between the two polymers in glass conversion temperature (T g) and crystallization. In brief, this work opens a new avenue for the production of lignin-derived chemicals and materials. [Display omitted] • Herbaceous plants show high potential for lignin valorization. • CuO/C could effectively catalytic hydrogenolysis of herbaceous lignin into monomers. • The chemical functionalization of purified hydroxycinnamates was proposed. • Lignin-derived polyesters revealed higher thermal stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multiple scale-up of FDCA -based polyesters from lab bench to pilot plant. • Comparable properties of FDCA-based polyesters by various scales. • Dependence of intrinsic viscosity on properties of PEF. • A ton-scale PEF resin had achieved in 3000L reactor. To accelerate the industrialization of 2,5-furan dicarboxylic acid (FDCA) based polyesters, it is essential to investigate the properties of FDCA-based polyesters prepared through scale-up experiments. In this work, poly(ethylene furanoate) (PEF) and poly(trimethylene furanoate) (PTF) were synthesized through lab bench (100 mL flask), pilot plant (5 and 150 L steel reactors). Additionally, the solid-state polycondensation industry was applied to enhance the intrinsic viscosities ([η]) of PEF and PTF to satisfy processing requirements in diverse fields, and the effect of the [η] on the machining, mechanical, and barrier property were further investigated. The results demonstrated that the tensile strengths of PEF and PTF prepared by 150 L steel reactor were 33.3% and 39.2% higher than these of 100 mL flask, which is attributed to the large-scale reactor can provide more accurate control for temperature, vacuum pressure, and mechanical stirring, etc. Moreover, FDCA-based polyesters with a high [η] have better proprieties. PEF and PTF demonstrated corresponding tensile strengths of 93.2 and 80.2 MPa and elastic modulus of 2.1 and 1.8 GPa when their [η] value is greater than 0.9 dL/g. Simultaneously, PEF and PTF have high barrier property for oxygen (0.019 and 0.022 barrer), carbon dioxide (0.018 and 0.032 barrer), and water vapor barrier (2.7 × 10−14 and 2.9 × 10−14 g·cm/cm2·s·Pa). Subsequently, a pilot scale (3000 L steel reactor) was used to prepare ton-scale PEF resin, fully meeting the application and development of FDCA-based polyester. The obtained results establish an entirely novel foundation for achieving large-scale applications and provide guidance for the industrial scale-up of FDCA-based polyesters. [ABSTRACT FROM AUTHOR]

• Copolymerization modification of poly(butylene succinate) by glycolic acid and L-lactic acid was comparatively studied. • The effect of comonomer content on physical properties was thoroughly discussed. • Copolymers exhibited excellent mechanical properties and high degradation rate. A series of bio-based poly(butylene succinate-co-glycolate) (PBSGA) and poly(butylene succinate-co-lactate) (PBSLA) random copolymers with similar comonomer content were synthesized by the incorporation of glycolic acid (GA) or L-lactic acid (L-LA) into poly(butylene succinate) (PBS) macromolecular chains so as to provide ideal monomer for rapid degradation. The microstructure and composition of copolymers were investigated by using the proton nuclear magnetic resonance (1H NMR). Different scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and polarizing optical microscopy (POM) techniques were used to further explore the thermal and crystallization properties. Although the introduction of comonomer weaken the crystallization ability of PBS, nucleation mechanism, crystal structure and crystal morphology did not change. In addition, shear rheological properties of PBS copolymers were preliminary investigated by rotary rheometer. PBSGA and PBSLA copolymers possessed splendid mechanical properties. Meanwhile, the degradation rate of copolymers was higher than PBS. Compared with PBSGA, the presence of side chain methyl in PBSLA weakens the crystallization properties and improves degradation rate. Besides, the composition, structure, thermal properties, crystallization and surface morphology of the copolymers were characterized by 1H NMR, DSC and scanning electron microscopy (SEM) during degradation process. In summary, the merge of L-LA or GA units not only enhances the hydrophilicity of the copolymers, but also improves the toughness and degradability without sacrificing mechanical properties. [ABSTRACT FROM AUTHOR]

Biodegradable polyesters with X-ray visibility for biomedical applications have attracted increasing attention. We herein reported a facile method of end-chain functionalization to prepare highly branched linear-comb poly (lactic acid) (Lc-PLA) using triiodobenzoic acid (TIBA) as end-capping and X-ray contrast agent. Three branch lengths of iodinated linear-comb poly (lactic acid) (I-Lc-PLA 30k , I-Lc-PLA 50k , and I-Lc-PLA 70k) were successfully synthesized and then microspheres with well-controlled size (average size ~180 μm) were prepared. By micro-CT testing, the results showed that shorter branch length of PLA contributed more iodinated end-group functionalized sites, leading a relatively high iodine content and excellent radiopacity. After terminated with TIBA, glass transition temperature and thermal stability of I-Lc-PLA polymers were greatly improved. During the in vitro hydrolytic degradation of three months, the molecular weight, iodine content, surface microstructure and micro-CT radiopacity of these microspheres were investigated. The degradation results showed that I-Lc-PLA 50k possessed sufficient iodine content and high household unit values, suggesting a well-maintained radiopacity of I-Lc-PLA. Therefore, this work proposed a highly branched I-Lc-PLA microspheres with promising CT-imaging capacity, which could be used as a long-term embolic material. Image 1 • X-ray opaque highly branched poly (lactic acid) were synthesized by using triiodobenzoic acid as end-capping agent. • The synthesized highly branched poly (lactic acid) exhibited high radiopacity performance with high molecular weight. • Non-invasive micro-CT imaging biodegradable embolic microspheres were developed. • In vitro degradation behavior of X-ray opaque microspheres was traced. [ABSTRACT FROM AUTHOR]

Poly(10-hydroxydecanoate) (PHDA) is of interest as a new-type aliphatic polyester due to its bioresource and flexible mechanical property. A series of PHDAs with varied molecular weights (M n from 27 kg/mol to 74 kg/mol) were prepared by optimized melt polycondensation of 10-hydroxydecanoic acid (HDA). Through DSC, WAXD, POM and tensile tests, the effects of molecular weight on the physical properties, including thermal properties, crystallization behavior, crystal morphology, rheological behavior and mechanical properties of PHDA were studied in detail. The results demonstrated that the physical properties of PHDA largely rely on the molecular weight. In particular, the brittle-ductile transition of PHDA occurred when the molecular weight increased up to 55 kg/mol. With the increase of molecular weight, the elongation at break was largely improved and finally exceeded 1400%. The ultimate tensile strength kept about 20 MPa. Hence, PHDA has a PE-like mechanical property. Our work highlights that PHDA is a polymer with excellent performance, which provides an alternative to durable petroleum resourced packaging materials. Image 1 • Poly(10-hydroxydecanoate) (PHDA) is of interest as a sustainable aliphatic polyester. • The dependence of physical properties of PHDA on molecular weight was explored. • PHDA shows well flexible mechanical property like PE. • PHDA is a promising alternative of durable petroleum resourced packaging materials. [ABSTRACT FROM AUTHOR]