Interfacial compatibilization is essential to generate compatible blend structures with synergistically enhanced properties.However,the effect of molecular structure on the reactivity of compatibilizers is not properl...Interfacial compatibilization is essential to generate compatible blend structures with synergistically enhanced properties.However,the effect of molecular structure on the reactivity of compatibilizers is not properly known.This study investigates the compatibilization effect of multifunctional,epoxy-based Joncryl chain extender in blends of polylactide(PLA)and polybutylene adipate-co-terephthalate(PBAT)using PLA with varying D-lactide contents and molecular weights.These PLAs were high molecular weight amorphous PLA(aPLA)with D-content of 12 mol%and semi-crystalline PLA(scPLA)grades with D-contents below 1.5 mol%at both high(h)and low(l)molecular weights.The reactivity of Joncryl was assessed with each individual neat polymer,and its compatibilization effectwas examined in blends at aweight ratio of 75 wt/25wt using small amplitude oscillatory shear(SAOS)rheological analysis.Differential scanning calorimetry(DSC),dynamic mechanical analysis(DMA),tensile and impact tests,as well as scanning electron microscopy(SEM)observations,were conducted to characterize the blends.The addition of Joncryl resulted in remarkable improvements rheological behavior of all neat polymers and noticeably refined PBAT droplets in all blends,particularly in aPLA/PBAT and scPLA(l)/PBAT.The ductility,toughness and impact strength of these blends were significantly enhanced,while their tensile strength and modulus also showed slight improvements.Although the addition of Joncryl retarded the crystallization of the scPLA samples,the scPLA(h)/PBAT blend with Joncryl exhibited the highest thermomechanical performance over a wide temperature range.This was attributed to the higher crystallinity of scPLA(h),which,even in the presence of Joncryl,provided high thermal stability.展开更多
Poly(L-lactide)(PLLA)is one of the best candidates as a bio-based plastic material for circular economy because of its biodegradability sustainability,recyclability,and good thermal and mechanical properties.The indus...Poly(L-lactide)(PLLA)is one of the best candidates as a bio-based plastic material for circular economy because of its biodegradability sustainability,recyclability,and good thermal and mechanical properties.The industrial production of PLLA is mainly from tin(II)_(2)-ethylhexanoate[Sn(Oct)_(2)]-catalyzed ring-opening polymerization(ROP)of L-LA in melt and bulk conditions at high temperatures(150-200℃).Despite the huge efforts devoted to the development of organometallics with low toxicity and many highly active catalysts under mild laboratory conditions,very few candidates can compete with Sn(Oct)_(2) under industrially relevant conditions.Herein,we report novel zinc complexes bearing phenylimino-pyridine-phenolate ligands as efficient catalysts for L-LA polymerization under both mild and industrially relevant conditions,with a turnover frequency as high as 6200 h^(-1).The best performing catalyst competed well with Sn(Oct)_(2) under industrial conditions and afforded colorless and semicrystalline PLLA.In addition,preliminary depolymerization experiments suggested that the new catalysts can also be used for the chemical recycling of commercial PLLA directly to L-LA with high selectivity under bulk and melt conditions.展开更多
Herein,the effect of in situ formation of the stereocomplex polylactide(sc-PLA)on the crystallization behaviors of poly(L-lactide)/poly(D-lactide)(PLLA/PDLA)blends was assessed.When the melt-blending temperature of th...Herein,the effect of in situ formation of the stereocomplex polylactide(sc-PLA)on the crystallization behaviors of poly(L-lactide)/poly(D-lactide)(PLLA/PDLA)blends was assessed.When the melt-blending temperature of the PLLA/PDLA blend approached the melting temperature of sc-PLA(approximately 220℃),a higher relative content of sc-PLA was achieved.Additionally,the relative content of sc-PLA in the PLLA/PDLA blend increased progressively with the increase in PDLA content.Differential scanning calorimetry analysis revealed that the overall crystallization rate of the homocrystal polylactide were enhanced by the presence of sc-PLA.After crystallization at the same temperature(115 and 120℃),the PLLA/PDLA blends exhibited a shorter half-crystallization time compared to PLLA alone.The size of the microcrystals of PLLA decreased as the sc-PLA content increased.Furthermore,the storage modulus and complex viscosity of the PLLA/PDLA blend increased with higher sc-PLA content.Dynamic mechanical analysis indicated that the glass transition temperature of PLLA in the PLLA/PDLA blends increased with increasing sc-PLA content.Additionally,the Vicat softening temperature increased from 67.8℃ for PLLA alone to 164.7℃ for the PLLA/25PDLA blend,enhancing the heat resistance of the PLLA/PDLA blends.Compared to PLLA alone,the hydrolytic resistance of the PLLA/PDLA blends showed marked improvement.展开更多
In this study,we prepared unentangled and slightly entangled poly(L-lactic acid)telechelic ionomer samples(Mn=5 and 16 kg/mol)based on sodium sulfonate groups.The telechelic samples exhibit extremely slow crystallizat...In this study,we prepared unentangled and slightly entangled poly(L-lactic acid)telechelic ionomer samples(Mn=5 and 16 kg/mol)based on sodium sulfonate groups.The telechelic samples exhibit extremely slow crystallization kinetics below the melting temperature T_(m) and above the glass transition temperature T_(g),which enables us to examine the linear viscoelasticity of the ionomer melt samples therein.The application of either the shear flow(at 85℃)or elongational flow(between 70 and 90℃)strongly accelerates the crystallization,leading to strong strain hardening and formation of highly orientedαcrystals.Depending on the relative average rates of the strain-induced dissociation and strain-induced crystallization,the stress evolution can be classified into two cases,and the critical work for strain-induced crystallization is higher in case where the strain-induced dissociation occurs earlier than the strain-induced crystallization.展开更多
Various sectors of the industry are searching for new materials with specific requirements,providing improved properties.The study presents novel composite materials based on polylactide that have been modified with t...Various sectors of the industry are searching for new materials with specific requirements,providing improved properties.The study presents novel composite materials based on polylactide that have been modified with the organosilicon compound,(3-thiopropyl)polysilsesquioxane(SSQ-SH).The SSQ-SH compound is a mixture of cage structures and not fully condensed random structures.The composite materials were obtained through injection moulding.The study includes a comprehensive characterization of the new materials that analyze their functional properties,such as rheology(MFR),mechanical strength(tensile strength,Charpy impact strength),and thermal properties.SEM microscopic photos were also taken to analyze the microstructure of the samples.The addition of a 5%by-weight organosilicon compound to polylactide resulted in a significant increase in MFR by 73.8%compared to the neat polymer.The greatest improvement in impact strength was achieved for the 5%SSQ-SH/PLA composite,increasing it by 32.0 kJ/m^(2)compared to PLA,which represents an increase of up to 187%.The conducted research confirms the possibility of modifying the properties of the polymer by employing organosilicon compounds.展开更多
Biodegradable poly （D,L-lactide） （PLA）/carboxyl-functionalized multi-walled carbon nanotubes （c-MWCNTs） composites were achieved via in-situ polymerization. These as-prepared composite materials were characteriz...Biodegradable poly （D,L-lactide） （PLA）/carboxyl-functionalized multi-walled carbon nanotubes （c-MWCNTs） composites were achieved via in-situ polymerization. These as-prepared composite materials were characterized with FT-IR, XRD, TG, DSC, SEM, and high insulation resistance meter. The results demonstrate that the multi-walled carbon nanotube was carboxyl functionalized, which improved the collection between c-MWCNTs and PLA, and further realized the graft copolymerization of c-MWCNTs and PLA. There is a higher glass transition temperature and a lower pyrolysis temperature of PLA/c-MWCNTs composites than pure PLA. The c-MWCNTs gave a better dispersion than unmodified MWCNTs in the PLA matrix, and an even coating of PLA on the surface of c-MWCNTs was obtained, which increased the interfacial interaction. High insulation resistance analysis showed that the addition of c-MWCNTs increased the electric conductivity, and c-MWCNTs performed against the large dielectric coefficient and electrostatic state of PLA. These results demonstrated that c-MWCNTs modified PLA composites were beneficial for potential application in the development of heat-resisting and conductivity plastic engineering.展开更多
Magnetic nano zinc ferrite fliuds were synthesized using an improved liquid phase chemical method, which would be used to replace tradditional iron oxides magnetic material. A novel copolymer （PLAA） with D, L-lacti...Magnetic nano zinc ferrite fliuds were synthesized using an improved liquid phase chemical method, which would be used to replace tradditional iron oxides magnetic material. A novel copolymer （PLAA） with D, L-lactide （D, L-LA） and alanine was synthesized using stannous octoate as initiator. Magnetic polymer microspheres were fabricated with nano zinc ferrite fluid coated with alanine modified poly lactide. These as-prepared zinc ferrite fluids, modified poly lactide and magnetic composites, were characterized with X-ray diffraction diffractometer, FT-IR spectrometer, nuclear magnetic resonance spectrometer, scanning electron microscope, transmission electron microscope, vibrating sample magnetometer, and thermogravimetric analyzer. The results demonstrate that the as-prepared zinc ferrite is spinel type of ZnFe2O4 nano crystals with particle size of 20-45 nm and magnetization of 32×10^-3 A.m2. Alanine is copolymerized with lactide, and the prepared composite magnetic microsphere is coated with the modified polylactide, with mass fraction of 45.5% of PLA, particle size ranging from 80-300 nm, and magnetization of 10.6×10^-3 A·m^2, which suggests ZnFe2O4 enjoys a stable magnetization after being coated by polymer.展开更多
Poly（propylene carbonate） （PPC） was blended with polylactide （PLA） and poly（1,2-propylene glycol adipate） （PPA） using a twin screw extruder. Then the PPC/PLA/PPA films were prepared using the blown film tech...Poly（propylene carbonate） （PPC） was blended with polylactide （PLA） and poly（1,2-propylene glycol adipate） （PPA） using a twin screw extruder. Then the PPC/PLA/PPA films were prepared using the blown film technique. DMA results showed that PPA could act as a plasticizer and improve the miscibility between PPC and PLA. Crystal morphology displayed that blending PLA with the amorphous PPC led to a decrease of the spherulite size of PLA. The results of mechanical tests indicated that PPC-rich films showed high elongation at break and PLA-rich films showed high tear strength and good optical properties. The content of PPC and PLA significantly affected the physical properties of the films. With increasing PPC content, the melt strengths of the PPC/PLA/PPA films were enhanced. These findings contributed to the biodegradable materials application for designing and manufacturing polymer packaging.展开更多
Polylactide(PLA)films blended with poly(butylene adipate-co-terephthalate)(PBAT)were hot melted using a twin screw extruder with the addition of triethyl citrate(TEC)as a plasticizer and toluene diisocyanate(TDI)as a ...Polylactide(PLA)films blended with poly(butylene adipate-co-terephthalate)(PBAT)were hot melted using a twin screw extruder with the addition of triethyl citrate(TEC)as a plasticizer and toluene diisocyanate(TDI)as a compatibilizer.The synergistic effects of the two additives on the mechanical,thermal,and morphological properties of the PLA/PBAT blend films were investigated.The influence of TEC content on the plasticized PLA films and the effect of TDI’s presence on the PLA/PBAT blend films were also studied by comparing them with neat PLA.The results showed a pronounced increase in elongation at break of the plasticized PLA films with increasing TEC levels,but a slight reduction in thermal stability.Also,the addition of TEC and TDI to the blend system not only synergistically enhanced the tensile properties and tensile-impact strength of the PLA/PBAT blends,but also affected their crystallinity and cold crystallization rate,a result of the improvement of interfacial interaction between PLA and PBAT,including the enhancement of their chain mobility.The synergy of the plasticization and compatibilization processes led to the improvement of tensile properties,tensile-impact strength,and compatibility of the blends,accelerating cold crystallization without affecting crystallization.展开更多
Polylactide （PLA） was successfully toughened by blending with bio-based poly（ester）urethane （TPU） elastomers which contained bio-based polyester soft segments synthesized from biomass diols and diacids. The misc...Polylactide （PLA） was successfully toughened by blending with bio-based poly（ester）urethane （TPU） elastomers which contained bio-based polyester soft segments synthesized from biomass diols and diacids. The miscibility, mechanical properties, phase morphology and toughening mechanism of the blend were investigated. Both DSC and DMTA results manifested that the addition of TPU elastomer not only accelerated the crystallization rate, but also increased the final degree of crystallinity, which proved that TPU has limited miscibility with PLA and has functioned as a plasticizer. All the blend samples showed distinct phase separation phenomenon with sea-island structure under SEM observation and the rubber particle size in the PLA matrix increased with the increased contents of TPU. The mechanical property variation of PLA/TPU blends could be quantitatively explained by Wu＇s model. With the variation of TPU, a brittle-ductile transition has been observed for the TPU/PLA blends. When these blends were under tensile stress conditions, the TPU particles could be debonded from the PLA matrix and the blends showed a high ability to induce large area plastic deformation before break, which was important for the dissipation of the breaking energy. Such mechanism was demonstrated by tensile tests and scanning electron microcopy （SEM） observations.展开更多
Sustainable blends of poly(propylene carbonate)(PPC)and stereocomplex polylactide(sc-PLA)were prepared by melt blending equimolar poly(L-lactic acid)(PLLA)and poly(D-lactide acid)(PDLA)with PPC to form sc-PLA crystals...Sustainable blends of poly(propylene carbonate)(PPC)and stereocomplex polylactide(sc-PLA)were prepared by melt blending equimolar poly(L-lactic acid)(PLLA)and poly(D-lactide acid)(PDLA)with PPC to form sc-PLA crystals in situ in the melt blending process.Differential seanning calorimetry analysis revealed that only sc-PLA,no homo-crystallization of PLLA or PDLA,formed in the PPC matrix as the sc-PLA con tent was more than 10 wt%.Very in triguingly,scan ning electronic microscopy observati on showed that sc-PLA was evenly dispersed in the PPC phase as spherical particles and the sizes of sc-PLA particles did not obviously increase with in creasing sc-PLA con tent.As a con seque nee,the rheological properties of PPC were greatly improved by incorporation of sc-PLA.When the sc-PLA con tent was 20 wt%,a percolati on n etwork structure was formed,and the blends showed solid-like behavior.The sc-PLA particles could reinforce the PPC matrix,especially at a temperature above the glass transition temperature of PPC.Moreover,the Vicat softening temperature of PPC/sc-PLA blends could be increased compared with that of neat PPC.展开更多
In this work, a series of high performance bio-based polyurethanes（bio-PUs） were synthesized from polylactide（PLA）-based diols, different diisocyanates（TDI, MDI, HDI, IPDI） and chain extender 1,4-butanediol, in ...In this work, a series of high performance bio-based polyurethanes（bio-PUs） were synthesized from polylactide（PLA）-based diols, different diisocyanates（TDI, MDI, HDI, IPDI） and chain extender 1,4-butanediol, in which different soft and hard segments are used to adjust their transition temperatures and mechanical properties. Poly（lactide-co-caprolactone）copolymer diols（co-PLAols） instead of PLA diols as the soft segment improved the thermal stability and mechanical properties of the synthesized bio-PUs. Among them, MDI-based bio-PUs have the highest T_g（43.8 °C）, tensile strength（23.5 MPa） and modulus（380.8 MPa）, while HDI-based bio-PUs have the lowest T_g（21.4 °C） and highest elongation at break（580%）. Especially, the bio-PUs synthesized from co-PLAols and MDI demonstrate better mechanical properties,closed to petroleum-based commodities. Furthermore, the obtained bio-PUs display good shape memory properties at body temperature and cytocompatibility. Therefore, these bio-PUs are promising for applications in biomedical fields.展开更多
Highly conductive polymer composites(CPCs) with excellent mechanical flexibility are ideal materials for designing excellent electromagnetic interference(EMI) shielding materials,which can be used for the electromagne...Highly conductive polymer composites(CPCs) with excellent mechanical flexibility are ideal materials for designing excellent electromagnetic interference(EMI) shielding materials,which can be used for the electromagnetic interference protection of flexible electronic devices.It is extremely urgent to fabricate ultra-strong EMI shielding CPCs with efficient conductive networks.In this paper,a novel silver-plated polylactide short fiber(Ag@PL ASF,AAF) was fabricated and was integrated with carbon nanotubes(CNT) to construct a multi-scale conductive network in polydimethylsiloxane(PDMS) matrix.The multi-scale conductive network endowed the flexible PDMS/AAF/CNT composite with excellent electrical conductivity of 440 S m-1and ultra-strong EMI shielding effectiveness(EMI SE) of up to 113 dB,containing only 5.0 vol% of AAF and 3.0 vol% of CNT(11.1wt% conductive filler content).Due to its excellent flexibility,the composite still showed 94% and 90% retention rates of EMI SE even after subjected to a simulated aging strategy(60℃ for 7 days) and 10,000 bending-releasing cycles.This strategy provides an important guidance for designing excellent EMI shielding materials to protect the workspace,environment and sensitive circuits against radiation for flexible electronic devices.展开更多
Polylactide(PLA),methyl methacrylate-butadiene-styrene copolymer(MBS),and poly(propylene carbonate)polyurethane(PPCU)were blended and subjected to blown film process.The rheological,mechanical,morphological,thermal,an...Polylactide(PLA),methyl methacrylate-butadiene-styrene copolymer(MBS),and poly(propylene carbonate)polyurethane(PPCU)were blended and subjected to blown film process.The rheological,mechanical,morphological,thermal,and crystalline properties of the PLA/MBS/PPCU ternary blends and the mechanical properties of the resulting films were studied.Results of mechanical test showed that PPCU and MBS could synergistically toughen PLA.The impact strength of 50/10/40 PLA/MBS/PPCU blend(74.7 k J/m^2)was about 7.5 times higher than that of the neat PLA(10.8 k J/m^2),and the elongation at break of 50/10/40 PLA/MBS/PPCU blend(276.5%)was higher by about 45 times that of PLA(6.2%).The tear strength of PLA/MBS/PPCU films was 20 k N/m higher than that of PLA,and the elongation at break(MD/TD)of 50/10/40 PLA/MBS/PPCU films was 271.1%/222.3%,whereas that of PLA was only 2.7%/3.0%.POM observations displayed that the density of spherulite nucleation increased and the size of crystalline particles decreased with the addition of MBS.With increasing PPCU content from 5%to 20%,the density of spherulite nucleation increased and the size of crystalline particles decreased continuously,but the nucleation density of spherulites was slightly lowered with increasing PPCU content from 30%to 40%.The PLA/MBS/PPCU films exhibited excellent mechanical properties,which expanded the application range of these biodegradable films.展开更多
The montmorillonite, a form of layered silicate, was successfully intercalated into polylactide （PLA） matrix through solvent-casting technique. In addition, PLA/MMT nanocomposite films were produced, in which homoge...The montmorillonite, a form of layered silicate, was successfully intercalated into polylactide （PLA） matrix through solvent-casting technique. In addition, PLA/MMT nanocomposite films were produced, in which homogenous distribution of the silicate lamellae plays a key role in the mechanical properties of the films. A small amount（5wt%） of OMMT intercalated into the PLA matrix resulted in their flexibility enhancement, from 3.68%（pure PLA film） to 352.65%. The results of wide-angle X-ray diffraction （WAXD） patterns confirmed that the silicate interlayer distance increased from 3.044 nm （for OMMT） to 3.56nm （for 5wt%, maximum） with increasing OMMT contents, but decreased to 3.319 nm when OMMT content was over 8wt%. FT-IR also verified the molecular-level associations between PLA chains and OMMT lamellae by vibration variances of hydrogen bonding. DSC thermograms demonstrated that thermal stabilities of the nanocomposite films enhanced, due to the silicate lamellae dispersed into PLA matrix.展开更多
A series of host-vip interaction-adjusted polylactide stereocomplex micelles was prepared via the self-assembly of 4-armed poly（ethylene glycol）-block-poly（L-lactide/D-lactide）-cholesterol （4-armed PEG-b-PLLA/P...A series of host-vip interaction-adjusted polylactide stereocomplex micelles was prepared via the self-assembly of 4-armed poly（ethylene glycol）-block-poly（L-lactide/D-lactide）-cholesterol （4-armed PEG-b-PLLA/PDLA-CHOL） and poly（β-cyclodextrin） （PCD） with the molar ratios of CHOL/β-CD at 1：0.5, 1 ：l, and 1：2 in an aqueous environment. The hydrodynamic diameters of the micelles ranged from 84.1 nm to 107 nm depending on the molar ratio of CHOL/β-CD. It was shown that the micelle with the largest proportion of PCD possessed excellent abilities in drug release, cell internalization as well as proliferation inhibitory effect toward human A549 lung cancer cells. The results demonstrated that the stereocomplex and host-vip interactions-mediated PLA micelles exhibited great potential in sustained drug delivery.展开更多
Polactide(PLA),poly(3-hydroxybutyrate-co-4-hydroxybutyrate)(P(3HB-CO-4HB)),and poly(butylene adipate co-terephthalate)(PBAT)ternary blends were prepared by extrusion blending.The biodegradable PLA/P(3HB-co 4HB)/PBAT f...Polactide(PLA),poly(3-hydroxybutyrate-co-4-hydroxybutyrate)(P(3HB-CO-4HB)),and poly(butylene adipate co-terephthalate)(PBAT)ternary blends were prepared by extrusion blending.The biodegradable PLA/P(3HB-co 4HB)/PBAT films were successfully obtained by using blown films technique.Excellnt siffness-toughness balance was achieved for 55/10/35 PLA/P(3HB-co 4HB)/PBAT film.The tensile strength reached 33.0 MPa(MD)and 23.5 MPa(TD).the elongation at break exceeded 1309%,and tear strength exceeded 110 kN/m.The Young's modulus as low as about 1800 MPa also met packaging applications.SEM observations revealed rough and long ligaments,indicating that the tear specimens were broken yieldingly.The addition of PBAT elastomers was the main reason for the improved toughness of the film.From DMA and SEM analysis,it was demonstrated that PLA P(3HB co 4HB),and PBAT were prilly compatible.With increasing P(3HB CO-4HB)content,the melt and cold crstallization of PLA was promoted.The enzymatic degradation experiments indicated that the films had good biodegradability.These findings gave important implications for designing and manufacturing biodegradation package of high biological carbon content.展开更多
Renewable and biodegradable polylactide (PLA) has excellent mechanical strength but is highly flammable which restricts its practical applications. Many phosphorus/nitrogen (P/N)-based flame retardants are ef- fective...Renewable and biodegradable polylactide (PLA) has excellent mechanical strength but is highly flammable which restricts its practical applications. Many phosphorus/nitrogen (P/N)-based flame retardants are ef- fective in PLA, but their high addition loading usually decreases the mechanical strength of the PLA bulk. For polyphosphoramides, despite high fire-retardant efficiency, their chemical synthesis often generates chemical wastes as byproducts. Herein, we report an atom-economic and highly efficient oligomeric P/N fire retardant (APN) prepared using a mild Michael addition polymerization with no byproducts. Using only 3 wt% APN, the resulting PLA exhibits desired fire retardancy including a UL-94 V-0 rating and a limiting oxygen index of 37.6%. Furthermore, the toughness of the fire-retardant PLA increases by 85% compared to pure PLA, with both tensile strength and thermal stability preserved. This work offers an atom-economic strategy for synthesizing highly efficient P/N fire retardants for use in the creation of fire-resistant PLA with robust mechanical properties.展开更多
Attempts were made to develop dyes with high affinity for polylactide as an alternative to the existent commercial disperse dyes. The dyes synthesized according to the affinity concept of dye to polylactide exhibited ...Attempts were made to develop dyes with high affinity for polylactide as an alternative to the existent commercial disperse dyes. The dyes synthesized according to the affinity concept of dye to polylactide exhibited excellent dyeing properties on polylactide compared with the commercial disperse dyes.展开更多
Polylactide(PLA)has often been blended with biodegradable poly(butylene adipate-co-terephthalate)(PBAT)to improve its toughness.However,the strength and heat resistance of PLA are always sacrificed.Herein,exchangeable...Polylactide(PLA)has often been blended with biodegradable poly(butylene adipate-co-terephthalate)(PBAT)to improve its toughness.However,the strength and heat resistance of PLA are always sacrificed.Herein,exchangeable hydroxyl-ester crosslinks are constructed in PLA/PBAT blends by successively introducing a tertiary amine-containing polyol,bis-(2-hydroxyethyl)amino-tris(hydroxymethyl)methane(BTM)and 4,4’-diphenylmethane diisocyanate(MDI)via reactive blending.BTM can react with both PLA and PBAT by transesterification,generating PLA or PBAT chains with terminal or pendant hydroxyl groups,which can then react with MDI to form networks.With internal catalysis of tertiary amine moiety in BTM,transesterification between the residual hydroxyl groups and ester bonds can occur at high temperatures,endowing the PLA/PBAT network with vitrimeric properties.Owning to the transesterification and chain extension reactions with MDI between PLA and PBAT,the interfacial adhesion is greatly improved.As a result of the excellent interfacial adhesion and the network structure,the prepared PLA/PBAT blends show greatly enhanced heat resistance and toughness(more than 40 times that of PLA)while maintaining high stiffness comparable to PLA.Furthermore,the prepared PLA/PBAT blends exhibit promising reconfigurable shape memory behavior.The present work provides a new and facile way to achieve high-performance and functional biodegradable polymeric materials.展开更多
基金supported by the Istanbul Technical University-Scientific Research Projects(ITUBAP)with project number of 45964Additional financial support was granted by the Scientific and Technological Research Council of Turkey(TUBITAK)under the 2218 Domestic Post-Doctoral Research Fellowship Program(Project No.118C574).
文摘Interfacial compatibilization is essential to generate compatible blend structures with synergistically enhanced properties.However,the effect of molecular structure on the reactivity of compatibilizers is not properly known.This study investigates the compatibilization effect of multifunctional,epoxy-based Joncryl chain extender in blends of polylactide(PLA)and polybutylene adipate-co-terephthalate(PBAT)using PLA with varying D-lactide contents and molecular weights.These PLAs were high molecular weight amorphous PLA(aPLA)with D-content of 12 mol%and semi-crystalline PLA(scPLA)grades with D-contents below 1.5 mol%at both high(h)and low(l)molecular weights.The reactivity of Joncryl was assessed with each individual neat polymer,and its compatibilization effectwas examined in blends at aweight ratio of 75 wt/25wt using small amplitude oscillatory shear(SAOS)rheological analysis.Differential scanning calorimetry(DSC),dynamic mechanical analysis(DMA),tensile and impact tests,as well as scanning electron microscopy(SEM)observations,were conducted to characterize the blends.The addition of Joncryl resulted in remarkable improvements rheological behavior of all neat polymers and noticeably refined PBAT droplets in all blends,particularly in aPLA/PBAT and scPLA(l)/PBAT.The ductility,toughness and impact strength of these blends were significantly enhanced,while their tensile strength and modulus also showed slight improvements.Although the addition of Joncryl retarded the crystallization of the scPLA samples,the scPLA(h)/PBAT blend with Joncryl exhibited the highest thermomechanical performance over a wide temperature range.This was attributed to the higher crystallinity of scPLA(h),which,even in the presence of Joncryl,provided high thermal stability.
基金supported by the National Natural Science Foundation of China(No.52222302)。
文摘Poly(L-lactide)(PLLA)is one of the best candidates as a bio-based plastic material for circular economy because of its biodegradability sustainability,recyclability,and good thermal and mechanical properties.The industrial production of PLLA is mainly from tin(II)_(2)-ethylhexanoate[Sn(Oct)_(2)]-catalyzed ring-opening polymerization(ROP)of L-LA in melt and bulk conditions at high temperatures(150-200℃).Despite the huge efforts devoted to the development of organometallics with low toxicity and many highly active catalysts under mild laboratory conditions,very few candidates can compete with Sn(Oct)_(2) under industrially relevant conditions.Herein,we report novel zinc complexes bearing phenylimino-pyridine-phenolate ligands as efficient catalysts for L-LA polymerization under both mild and industrially relevant conditions,with a turnover frequency as high as 6200 h^(-1).The best performing catalyst competed well with Sn(Oct)_(2) under industrial conditions and afforded colorless and semicrystalline PLLA.In addition,preliminary depolymerization experiments suggested that the new catalysts can also be used for the chemical recycling of commercial PLLA directly to L-LA with high selectivity under bulk and melt conditions.
基金supported by the Science and Technology Development Plan Project of Jilin Province of China(No.20250203127SF)Chinese Academy of Sciences(Changchun Branch)(No.2025SYHZ0045)+1 种基金Science and Technology Bureau of Jilin Province of China(No.20240302126GX)Science and Technology Bureau of Changchun City of China(No.23SH08).
文摘Herein,the effect of in situ formation of the stereocomplex polylactide(sc-PLA)on the crystallization behaviors of poly(L-lactide)/poly(D-lactide)(PLLA/PDLA)blends was assessed.When the melt-blending temperature of the PLLA/PDLA blend approached the melting temperature of sc-PLA(approximately 220℃),a higher relative content of sc-PLA was achieved.Additionally,the relative content of sc-PLA in the PLLA/PDLA blend increased progressively with the increase in PDLA content.Differential scanning calorimetry analysis revealed that the overall crystallization rate of the homocrystal polylactide were enhanced by the presence of sc-PLA.After crystallization at the same temperature(115 and 120℃),the PLLA/PDLA blends exhibited a shorter half-crystallization time compared to PLLA alone.The size of the microcrystals of PLLA decreased as the sc-PLA content increased.Furthermore,the storage modulus and complex viscosity of the PLLA/PDLA blend increased with higher sc-PLA content.Dynamic mechanical analysis indicated that the glass transition temperature of PLLA in the PLLA/PDLA blends increased with increasing sc-PLA content.Additionally,the Vicat softening temperature increased from 67.8℃ for PLLA alone to 164.7℃ for the PLLA/25PDLA blend,enhancing the heat resistance of the PLLA/PDLA blends.Compared to PLLA alone,the hydrolytic resistance of the PLLA/PDLA blends showed marked improvement.
基金This work was financially supported by the National Natural Science Foundation of China(No.22173095).
文摘In this study,we prepared unentangled and slightly entangled poly(L-lactic acid)telechelic ionomer samples(Mn=5 and 16 kg/mol)based on sodium sulfonate groups.The telechelic samples exhibit extremely slow crystallization kinetics below the melting temperature T_(m) and above the glass transition temperature T_(g),which enables us to examine the linear viscoelasticity of the ionomer melt samples therein.The application of either the shear flow(at 85℃)or elongational flow(between 70 and 90℃)strongly accelerates the crystallization,leading to strong strain hardening and formation of highly orientedαcrystals.Depending on the relative average rates of the strain-induced dissociation and strain-induced crystallization,the stress evolution can be classified into two cases,and the critical work for strain-induced crystallization is higher in case where the strain-induced dissociation occurs earlier than the strain-induced crystallization.
基金supported by the Smart Growth Operational Programme(No.POIR.04.02.00-00-D003/20-00)European Funds(No.RPWP.01.01.00-30-0004/18)Ministry of Science and Higher Education(No.21/529535/SPUB/SP/2022).
文摘Various sectors of the industry are searching for new materials with specific requirements,providing improved properties.The study presents novel composite materials based on polylactide that have been modified with the organosilicon compound,(3-thiopropyl)polysilsesquioxane(SSQ-SH).The SSQ-SH compound is a mixture of cage structures and not fully condensed random structures.The composite materials were obtained through injection moulding.The study includes a comprehensive characterization of the new materials that analyze their functional properties,such as rheology(MFR),mechanical strength(tensile strength,Charpy impact strength),and thermal properties.SEM microscopic photos were also taken to analyze the microstructure of the samples.The addition of a 5%by-weight organosilicon compound to polylactide resulted in a significant increase in MFR by 73.8%compared to the neat polymer.The greatest improvement in impact strength was achieved for the 5%SSQ-SH/PLA composite,increasing it by 32.0 kJ/m^(2)compared to PLA,which represents an increase of up to 187%.The conducted research confirms the possibility of modifying the properties of the polymer by employing organosilicon compounds.
基金Projects(21107032,51073072)supported by the National Natural Science Foundation of ChinaProjects(Y406469,Y4110555,Y4100745)supported by Natural Science Foundation of Zhejiang Province,ChinaProjects(2011AY1048-5,2011AY1030)supported by the Science Foundation of Jiaxing Science and Technology Bureau,China
文摘Biodegradable poly （D,L-lactide） （PLA）/carboxyl-functionalized multi-walled carbon nanotubes （c-MWCNTs） composites were achieved via in-situ polymerization. These as-prepared composite materials were characterized with FT-IR, XRD, TG, DSC, SEM, and high insulation resistance meter. The results demonstrate that the multi-walled carbon nanotube was carboxyl functionalized, which improved the collection between c-MWCNTs and PLA, and further realized the graft copolymerization of c-MWCNTs and PLA. There is a higher glass transition temperature and a lower pyrolysis temperature of PLA/c-MWCNTs composites than pure PLA. The c-MWCNTs gave a better dispersion than unmodified MWCNTs in the PLA matrix, and an even coating of PLA on the surface of c-MWCNTs was obtained, which increased the interfacial interaction. High insulation resistance analysis showed that the addition of c-MWCNTs increased the electric conductivity, and c-MWCNTs performed against the large dielectric coefficient and electrostatic state of PLA. These results demonstrated that c-MWCNTs modified PLA composites were beneficial for potential application in the development of heat-resisting and conductivity plastic engineering.
基金Project (21107032) supported by the National Natural Science Foundation of ChinaProjects (Y406469,Y4110606) supported by Natural Science Foundation of Zhejiang Province, China+1 种基金Projects (2008AY2018,2011AY1048-5,2011AY1030) supported by the Science Foundation of Jiaxing Science and Technology Bureau,ChinaProject (2009C21003) supported by Science and Technology Department of Zhejiang Province,China
文摘Magnetic nano zinc ferrite fliuds were synthesized using an improved liquid phase chemical method, which would be used to replace tradditional iron oxides magnetic material. A novel copolymer （PLAA） with D, L-lactide （D, L-LA） and alanine was synthesized using stannous octoate as initiator. Magnetic polymer microspheres were fabricated with nano zinc ferrite fluid coated with alanine modified poly lactide. These as-prepared zinc ferrite fluids, modified poly lactide and magnetic composites, were characterized with X-ray diffraction diffractometer, FT-IR spectrometer, nuclear magnetic resonance spectrometer, scanning electron microscope, transmission electron microscope, vibrating sample magnetometer, and thermogravimetric analyzer. The results demonstrate that the as-prepared zinc ferrite is spinel type of ZnFe2O4 nano crystals with particle size of 20-45 nm and magnetization of 32×10^-3 A.m2. Alanine is copolymerized with lactide, and the prepared composite magnetic microsphere is coated with the modified polylactide, with mass fraction of 45.5% of PLA, particle size ranging from 80-300 nm, and magnetization of 10.6×10^-3 A·m^2, which suggests ZnFe2O4 enjoys a stable magnetization after being coated by polymer.
基金financially supported by the fund of Science&Technology Bureau of Jilin Province of China(No.20130305028NY)Chinese Science Academy(Changchun Branch)(No.2014SYHZ0019)+1 种基金the National High Technology Research and Development Program of China(863 Program)(No.2012AA062904)the National Natural Science Foundation of China(No.51021003)
文摘Poly（propylene carbonate） （PPC） was blended with polylactide （PLA） and poly（1,2-propylene glycol adipate） （PPA） using a twin screw extruder. Then the PPC/PLA/PPA films were prepared using the blown film technique. DMA results showed that PPA could act as a plasticizer and improve the miscibility between PPC and PLA. Crystal morphology displayed that blending PLA with the amorphous PPC led to a decrease of the spherulite size of PLA. The results of mechanical tests indicated that PPC-rich films showed high elongation at break and PLA-rich films showed high tear strength and good optical properties. The content of PPC and PLA significantly affected the physical properties of the films. With increasing PPC content, the melt strengths of the PPC/PLA/PPA films were enhanced. These findings contributed to the biodegradable materials application for designing and manufacturing polymer packaging.
基金financially supported by Development and Promotion of Science and Technology Talents (DPST) (No. 013/2559)
文摘Polylactide(PLA)films blended with poly(butylene adipate-co-terephthalate)(PBAT)were hot melted using a twin screw extruder with the addition of triethyl citrate(TEC)as a plasticizer and toluene diisocyanate(TDI)as a compatibilizer.The synergistic effects of the two additives on the mechanical,thermal,and morphological properties of the PLA/PBAT blend films were investigated.The influence of TEC content on the plasticized PLA films and the effect of TDI’s presence on the PLA/PBAT blend films were also studied by comparing them with neat PLA.The results showed a pronounced increase in elongation at break of the plasticized PLA films with increasing TEC levels,but a slight reduction in thermal stability.Also,the addition of TEC and TDI to the blend system not only synergistically enhanced the tensile properties and tensile-impact strength of the PLA/PBAT blends,but also affected their crystallinity and cold crystallization rate,a result of the improvement of interfacial interaction between PLA and PBAT,including the enhancement of their chain mobility.The synergy of the plasticization and compatibilization processes led to the improvement of tensile properties,tensile-impact strength,and compatibility of the blends,accelerating cold crystallization without affecting crystallization.
文摘Polylactide （PLA） was successfully toughened by blending with bio-based poly（ester）urethane （TPU） elastomers which contained bio-based polyester soft segments synthesized from biomass diols and diacids. The miscibility, mechanical properties, phase morphology and toughening mechanism of the blend were investigated. Both DSC and DMTA results manifested that the addition of TPU elastomer not only accelerated the crystallization rate, but also increased the final degree of crystallinity, which proved that TPU has limited miscibility with PLA and has functioned as a plasticizer. All the blend samples showed distinct phase separation phenomenon with sea-island structure under SEM observation and the rubber particle size in the PLA matrix increased with the increased contents of TPU. The mechanical property variation of PLA/TPU blends could be quantitatively explained by Wu＇s model. With the variation of TPU, a brittle-ductile transition has been observed for the TPU/PLA blends. When these blends were under tensile stress conditions, the TPU particles could be debonded from the PLA matrix and the blends showed a high ability to induce large area plastic deformation before break, which was important for the dissipation of the breaking energy. Such mechanism was demonstrated by tensile tests and scanning electron microcopy （SEM） observations.
基金the Chinese Academy of scienee and technology service network planning(No.KFJSTS-QYZD-140)a program of Cooperation of Hubei Province and Chinese Academy of Sciences,Innovation team project of Beijing Institute of Science and Technology(No.IG201703N)"13^th five-year"Science and Technology Research Program of the Education Department of Jilin Provinee(No.JJKH20190862KJ).
文摘Sustainable blends of poly(propylene carbonate)(PPC)and stereocomplex polylactide(sc-PLA)were prepared by melt blending equimolar poly(L-lactic acid)(PLLA)and poly(D-lactide acid)(PDLA)with PPC to form sc-PLA crystals in situ in the melt blending process.Differential seanning calorimetry analysis revealed that only sc-PLA,no homo-crystallization of PLLA or PDLA,formed in the PPC matrix as the sc-PLA con tent was more than 10 wt%.Very in triguingly,scan ning electronic microscopy observati on showed that sc-PLA was evenly dispersed in the PPC phase as spherical particles and the sizes of sc-PLA particles did not obviously increase with in creasing sc-PLA con tent.As a con seque nee,the rheological properties of PPC were greatly improved by incorporation of sc-PLA.When the sc-PLA con tent was 20 wt%,a percolati on n etwork structure was formed,and the blends showed solid-like behavior.The sc-PLA particles could reinforce the PPC matrix,especially at a temperature above the glass transition temperature of PPC.Moreover,the Vicat softening temperature of PPC/sc-PLA blends could be increased compared with that of neat PPC.
基金financially supported by the National Natural Science Foundation of China(No.21404112)Ningbo Key Scientific and Technological Project(No.2014B10023)+2 种基金Ningbo Natural Science Foundation(No.2015A610016)Open Project of Key Laboratory of Marine Materials and Related Technologies(No.2016K07)Ningbo Science and Technology Innovation Team(No.2015B11003)
文摘In this work, a series of high performance bio-based polyurethanes（bio-PUs） were synthesized from polylactide（PLA）-based diols, different diisocyanates（TDI, MDI, HDI, IPDI） and chain extender 1,4-butanediol, in which different soft and hard segments are used to adjust their transition temperatures and mechanical properties. Poly（lactide-co-caprolactone）copolymer diols（co-PLAols） instead of PLA diols as the soft segment improved the thermal stability and mechanical properties of the synthesized bio-PUs. Among them, MDI-based bio-PUs have the highest T_g（43.8 °C）, tensile strength（23.5 MPa） and modulus（380.8 MPa）, while HDI-based bio-PUs have the lowest T_g（21.4 °C） and highest elongation at break（580%）. Especially, the bio-PUs synthesized from co-PLAols and MDI demonstrate better mechanical properties,closed to petroleum-based commodities. Furthermore, the obtained bio-PUs display good shape memory properties at body temperature and cytocompatibility. Therefore, these bio-PUs are promising for applications in biomedical fields.
基金supported by the National Natural Science Foundation of China(Nos.51973142,52033005,52003169).
文摘Highly conductive polymer composites(CPCs) with excellent mechanical flexibility are ideal materials for designing excellent electromagnetic interference(EMI) shielding materials,which can be used for the electromagnetic interference protection of flexible electronic devices.It is extremely urgent to fabricate ultra-strong EMI shielding CPCs with efficient conductive networks.In this paper,a novel silver-plated polylactide short fiber(Ag@PL ASF,AAF) was fabricated and was integrated with carbon nanotubes(CNT) to construct a multi-scale conductive network in polydimethylsiloxane(PDMS) matrix.The multi-scale conductive network endowed the flexible PDMS/AAF/CNT composite with excellent electrical conductivity of 440 S m-1and ultra-strong EMI shielding effectiveness(EMI SE) of up to 113 dB,containing only 5.0 vol% of AAF and 3.0 vol% of CNT(11.1wt% conductive filler content).Due to its excellent flexibility,the composite still showed 94% and 90% retention rates of EMI SE even after subjected to a simulated aging strategy(60℃ for 7 days) and 10,000 bending-releasing cycles.This strategy provides an important guidance for designing excellent EMI shielding materials to protect the workspace,environment and sensitive circuits against radiation for flexible electronic devices.
基金financially supported by the National Science Foundation of Zhejiang Province of China (No. LQY19B040001)the fund of Science and Technology Bureau of Jilin Province of China (No. 20170204012SF)+1 种基金the Program of Changchun Science and Technology Bureau (No. 16CX23)National Key Research and Development Program of China (No. 2016YFC0501402-5)
文摘Polylactide(PLA),methyl methacrylate-butadiene-styrene copolymer(MBS),and poly(propylene carbonate)polyurethane(PPCU)were blended and subjected to blown film process.The rheological,mechanical,morphological,thermal,and crystalline properties of the PLA/MBS/PPCU ternary blends and the mechanical properties of the resulting films were studied.Results of mechanical test showed that PPCU and MBS could synergistically toughen PLA.The impact strength of 50/10/40 PLA/MBS/PPCU blend(74.7 k J/m^2)was about 7.5 times higher than that of the neat PLA(10.8 k J/m^2),and the elongation at break of 50/10/40 PLA/MBS/PPCU blend(276.5%)was higher by about 45 times that of PLA(6.2%).The tear strength of PLA/MBS/PPCU films was 20 k N/m higher than that of PLA,and the elongation at break(MD/TD)of 50/10/40 PLA/MBS/PPCU films was 271.1%/222.3%,whereas that of PLA was only 2.7%/3.0%.POM observations displayed that the density of spherulite nucleation increased and the size of crystalline particles decreased with the addition of MBS.With increasing PPCU content from 5%to 20%,the density of spherulite nucleation increased and the size of crystalline particles decreased continuously,but the nucleation density of spherulites was slightly lowered with increasing PPCU content from 30%to 40%.The PLA/MBS/PPCU films exhibited excellent mechanical properties,which expanded the application range of these biodegradable films.
文摘The montmorillonite, a form of layered silicate, was successfully intercalated into polylactide （PLA） matrix through solvent-casting technique. In addition, PLA/MMT nanocomposite films were produced, in which homogenous distribution of the silicate lamellae plays a key role in the mechanical properties of the films. A small amount（5wt%） of OMMT intercalated into the PLA matrix resulted in their flexibility enhancement, from 3.68%（pure PLA film） to 352.65%. The results of wide-angle X-ray diffraction （WAXD） patterns confirmed that the silicate interlayer distance increased from 3.044 nm （for OMMT） to 3.56nm （for 5wt%, maximum） with increasing OMMT contents, but decreased to 3.319 nm when OMMT content was over 8wt%. FT-IR also verified the molecular-level associations between PLA chains and OMMT lamellae by vibration variances of hydrogen bonding. DSC thermograms demonstrated that thermal stabilities of the nanocomposite films enhanced, due to the silicate lamellae dispersed into PLA matrix.
基金financially supported by the National Natural Science Foundation of China(Nos.51673190,51303174,51603204 and 51390484)
文摘A series of host-vip interaction-adjusted polylactide stereocomplex micelles was prepared via the self-assembly of 4-armed poly（ethylene glycol）-block-poly（L-lactide/D-lactide）-cholesterol （4-armed PEG-b-PLLA/PDLA-CHOL） and poly（β-cyclodextrin） （PCD） with the molar ratios of CHOL/β-CD at 1：0.5, 1 ：l, and 1：2 in an aqueous environment. The hydrodynamic diameters of the micelles ranged from 84.1 nm to 107 nm depending on the molar ratio of CHOL/β-CD. It was shown that the micelle with the largest proportion of PCD possessed excellent abilities in drug release, cell internalization as well as proliferation inhibitory effect toward human A549 lung cancer cells. The results demonstrated that the stereocomplex and host-vip interactions-mediated PLA micelles exhibited great potential in sustained drug delivery.
基金This work was financially supported by the fund of Science and Technology Bureau of Jilin Province of China(No.201702040125F)Chinese Academy of Sciences(Changchun Branch)(No.2020SYHZ0002)+1 种基金Science and Technology Services Network Program of Chinese Academy of Sciences(STS Project)(No.KFJ-STS-ZDTP-082)the National Science Foundation of Zhejiang Province of China(No.LQY19B040001).
文摘Polactide(PLA),poly(3-hydroxybutyrate-co-4-hydroxybutyrate)(P(3HB-CO-4HB)),and poly(butylene adipate co-terephthalate)(PBAT)ternary blends were prepared by extrusion blending.The biodegradable PLA/P(3HB-co 4HB)/PBAT films were successfully obtained by using blown films technique.Excellnt siffness-toughness balance was achieved for 55/10/35 PLA/P(3HB-co 4HB)/PBAT film.The tensile strength reached 33.0 MPa(MD)and 23.5 MPa(TD).the elongation at break exceeded 1309%,and tear strength exceeded 110 kN/m.The Young's modulus as low as about 1800 MPa also met packaging applications.SEM observations revealed rough and long ligaments,indicating that the tear specimens were broken yieldingly.The addition of PBAT elastomers was the main reason for the improved toughness of the film.From DMA and SEM analysis,it was demonstrated that PLA P(3HB co 4HB),and PBAT were prilly compatible.With increasing P(3HB CO-4HB)content,the melt and cold crstallization of PLA was promoted.The enzymatic degradation experiments indicated that the films had good biodegradability.These findings gave important implications for designing and manufacturing biodegradation package of high biological carbon content.
基金the National Natural Science Foundation of China(No.21801097)the Australian Re-search Council(Nos.DP190102992 and FT190100188).
文摘Renewable and biodegradable polylactide (PLA) has excellent mechanical strength but is highly flammable which restricts its practical applications. Many phosphorus/nitrogen (P/N)-based flame retardants are ef- fective in PLA, but their high addition loading usually decreases the mechanical strength of the PLA bulk. For polyphosphoramides, despite high fire-retardant efficiency, their chemical synthesis often generates chemical wastes as byproducts. Herein, we report an atom-economic and highly efficient oligomeric P/N fire retardant (APN) prepared using a mild Michael addition polymerization with no byproducts. Using only 3 wt% APN, the resulting PLA exhibits desired fire retardancy including a UL-94 V-0 rating and a limiting oxygen index of 37.6%. Furthermore, the toughness of the fire-retardant PLA increases by 85% compared to pure PLA, with both tensile strength and thermal stability preserved. This work offers an atom-economic strategy for synthesizing highly efficient P/N fire retardants for use in the creation of fire-resistant PLA with robust mechanical properties.
文摘Attempts were made to develop dyes with high affinity for polylactide as an alternative to the existent commercial disperse dyes. The dyes synthesized according to the affinity concept of dye to polylactide exhibited excellent dyeing properties on polylactide compared with the commercial disperse dyes.
基金financially supported by the National Natural Science Foundation of China(Nos.21975108 and 52103082)Fundamental Research Funds for the Central Universities(No.JUSRP122016)Wuxi"Light of Taihu Lake"Science and Technology Research Plan(Basic Research,No.K20221008).
文摘Polylactide(PLA)has often been blended with biodegradable poly(butylene adipate-co-terephthalate)(PBAT)to improve its toughness.However,the strength and heat resistance of PLA are always sacrificed.Herein,exchangeable hydroxyl-ester crosslinks are constructed in PLA/PBAT blends by successively introducing a tertiary amine-containing polyol,bis-(2-hydroxyethyl)amino-tris(hydroxymethyl)methane(BTM)and 4,4’-diphenylmethane diisocyanate(MDI)via reactive blending.BTM can react with both PLA and PBAT by transesterification,generating PLA or PBAT chains with terminal or pendant hydroxyl groups,which can then react with MDI to form networks.With internal catalysis of tertiary amine moiety in BTM,transesterification between the residual hydroxyl groups and ester bonds can occur at high temperatures,endowing the PLA/PBAT network with vitrimeric properties.Owning to the transesterification and chain extension reactions with MDI between PLA and PBAT,the interfacial adhesion is greatly improved.As a result of the excellent interfacial adhesion and the network structure,the prepared PLA/PBAT blends show greatly enhanced heat resistance and toughness(more than 40 times that of PLA)while maintaining high stiffness comparable to PLA.Furthermore,the prepared PLA/PBAT blends exhibit promising reconfigurable shape memory behavior.The present work provides a new and facile way to achieve high-performance and functional biodegradable polymeric materials.
