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
Polylactide(PLA)/poly(butylene adipate-co-terephthalate)(PBAT)blend nanocomposites including 3 wt%of cel-lulose nanocrystals(CNCs)were prepared by melt compounding method in a twin-screw extruder and an inter-nal mixe...Polylactide(PLA)/poly(butylene adipate-co-terephthalate)(PBAT)blend nanocomposites including 3 wt%of cel-lulose nanocrystals(CNCs)were prepared by melt compounding method in a twin-screw extruder and an inter-nal mixer.Blend nanocomposites were formulated by diluting three different masterbatches prepared by solution casting method that contained 7 wt%of CNC.These masterbatches were:(m1)PLA/PBAT/CNC masterbatch;(m2)PLA/CNC masterbatch;and(m3)PBAT/CNC masterbatch.These were to explore how different prepara-tion methods affect the dispersion and localization of CNC and hence the properties of PLA/PBAT/CNC blend nanocomposites.Scanning electron microscopy(SEM)was used to study the structural changes of the blends.Rheological properties of PLA/PBAT blends and PLA/PBAT/CNC blend nanocomposites were also investigated.In the samples prepared by internal mixer,the rheological behavior of blend nanocomposite prepared through premixing of CNC particles with PLA showed a transition from liquid-like to a gel-like behavior.According to the rheological results and differential scanning calorimetry(DSC)analysis,it was found that the CNC overall enhanced the viscoelastic properties of blends and improved the PLA crystallization,respectively.Dynamic mechanical analysis(DMA)illustrated that the incorporation of CNC also enhanced the elastic modulus of PLA/PBAT blends specifically above the glass transition temperature of PLA.The expected improvements in mechanical properties did not occur due to the possible existence of residual solvent in the blends.展开更多
Because of rapid progress in the electronics industry,the market has faced a huge demand for novel materials in the field of electromagnetic interference(EMI)shielding.Conductive functional polymer composites have dem...Because of rapid progress in the electronics industry,the market has faced a huge demand for novel materials in the field of electromagnetic interference(EMI)shielding.Conductive functional polymer composites have demonstrated great potential to fulfill this requirement.To synthesize the polymeric composites,functional conductive nanoadditives such as graphene,carbon nanotubes,and MXene are commonly added to polymeric matrices,and the conductive polymer nanocomposites exhibit promising electrical conductivity as well as EMI shielding performance.Additive manufacturing(AM),also referred to as threedimensional(3D)printing,has been increasingly employed to fabricate complicated geometry components in the medical,aerospace,and automotive industries.AM has also been used to fabricate advanced EMI shielding materials for sensors,supercapacitors,energy storage devices,and flexible electronics.This review aims at introducing the different 3D printing methods applied for the fabrication of EMI shielding polymer nanocomposites.The impact of the AM process on the functionality of the samples is also reviewed.Additionally,the influence of the nanofiller type and amount on the microstructure and performance of the fabricated nanocomposites is discussed.Finally,the prospects and recommended works for future study are outlined.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The authors would like to acknowledge the financial supports by the Scientific and Technological Research Council of Turkey(TUBITAK)in the Context of 1001 Project with the Project No.of 117M238.
文摘Polylactide(PLA)/poly(butylene adipate-co-terephthalate)(PBAT)blend nanocomposites including 3 wt%of cel-lulose nanocrystals(CNCs)were prepared by melt compounding method in a twin-screw extruder and an inter-nal mixer.Blend nanocomposites were formulated by diluting three different masterbatches prepared by solution casting method that contained 7 wt%of CNC.These masterbatches were:(m1)PLA/PBAT/CNC masterbatch;(m2)PLA/CNC masterbatch;and(m3)PBAT/CNC masterbatch.These were to explore how different prepara-tion methods affect the dispersion and localization of CNC and hence the properties of PLA/PBAT/CNC blend nanocomposites.Scanning electron microscopy(SEM)was used to study the structural changes of the blends.Rheological properties of PLA/PBAT blends and PLA/PBAT/CNC blend nanocomposites were also investigated.In the samples prepared by internal mixer,the rheological behavior of blend nanocomposite prepared through premixing of CNC particles with PLA showed a transition from liquid-like to a gel-like behavior.According to the rheological results and differential scanning calorimetry(DSC)analysis,it was found that the CNC overall enhanced the viscoelastic properties of blends and improved the PLA crystallization,respectively.Dynamic mechanical analysis(DMA)illustrated that the incorporation of CNC also enhanced the elastic modulus of PLA/PBAT blends specifically above the glass transition temperature of PLA.The expected improvements in mechanical properties did not occur due to the possible existence of residual solvent in the blends.
文摘Because of rapid progress in the electronics industry,the market has faced a huge demand for novel materials in the field of electromagnetic interference(EMI)shielding.Conductive functional polymer composites have demonstrated great potential to fulfill this requirement.To synthesize the polymeric composites,functional conductive nanoadditives such as graphene,carbon nanotubes,and MXene are commonly added to polymeric matrices,and the conductive polymer nanocomposites exhibit promising electrical conductivity as well as EMI shielding performance.Additive manufacturing(AM),also referred to as threedimensional(3D)printing,has been increasingly employed to fabricate complicated geometry components in the medical,aerospace,and automotive industries.AM has also been used to fabricate advanced EMI shielding materials for sensors,supercapacitors,energy storage devices,and flexible electronics.This review aims at introducing the different 3D printing methods applied for the fabrication of EMI shielding polymer nanocomposites.The impact of the AM process on the functionality of the samples is also reviewed.Additionally,the influence of the nanofiller type and amount on the microstructure and performance of the fabricated nanocomposites is discussed.Finally,the prospects and recommended works for future study are outlined.
