The aim of this work was to use cellulose nanocrystals that were obtained by hydrolysis in phosphoric acid solution and further modified with succinic anhydride in the microwave field for PLA reinforcement.A series of...The aim of this work was to use cellulose nanocrystals that were obtained by hydrolysis in phosphoric acid solution and further modified with succinic anhydride in the microwave field for PLA reinforcement.A series of allbionanocomposites containing unmodified and surface modified cellulose nanocrystals with CNC content in the range of 1–3%_(w.t.) were obtained by melt blending and tested by XRD,SEM,DSC and DMA to investigate the effect of surface esterification of CNCs on the structure,morphology,dynamic mechanical properties of bionanocomposites,as well as phase transitions of PLA in the presence of cellulosic nanofiller.DMA investigations showed the highest increase of storage modulus by ca.7%(335 MPa at 25℃)in the glassy state of PLA for 2%_(w.t.)of unmodified CNC.Though,addition of 2%_(w.t.)of succinylated CNCs caused the highest increase of the onset of glass transition temperature(by 6.2℃)thus widening the temperature range of biocomposite application.The increase of glass transition temperature indicates the strongest interfacial interactions due to improved miscibility of surface modified nanocrystals and thus good dispersion of additive in PLA matrix providing high interface.展开更多
In order to extend the usage of PLA-based nanocomposites, the modification of multi-walled carbon nanotubes (MWCNT) and preparation of surfactant modified carbon nanotubes (SMCNT) involved PLA nanocomposites (PLA/SMCN...In order to extend the usage of PLA-based nanocomposites, the modification of multi-walled carbon nanotubes (MWCNT) and preparation of surfactant modified carbon nanotubes (SMCNT) involved PLA nanocomposites (PLA/SMCNT) were investigated. The morphologies, electrical properties and crystallization behavior of PLA/SMCNT composites were investigated. The TEM images indicated that SMCNTs were dispersed homogenously in the PLA matrix without forming aggregates. The electrical conductivity of PLA/SMCNT was greatly improved and the percolation threshold of PLA/SMCNT was calculated to be 0.61% which is much lower than 1.45% of PLA/MWCNT composite. The crystallization behavior suggested that SDBS together with MWCNT acted as heterogeneous nucleating agent and accelerated the nucleation. Meanwhile, the SMCNT also devoted further restrained effect to spherulites growth due to its well dispersion and improved compatibility with matrix.展开更多
Polymeric biomaterials such as polylactic acid(PLA)play a prominent role in the advancement of biomedical additive manufacturing(AM).PLA offers indeed a very advantageous combination of thermomechanical properties and...Polymeric biomaterials such as polylactic acid(PLA)play a prominent role in the advancement of biomedical additive manufacturing(AM).PLA offers indeed a very advantageous combination of thermomechanical properties and functional attributes,as it is biobased,biodegradable,biocompatible and easy to print.However,PLA can be damaged by common sterilization methods and is sensitive to most chemical disinfectants,and this may impair its widespread usage.One of the most promising ways to overcome this shortcoming is to provide PLA with embedded antibacterial activity by the addition of appropriate fillers such as zinc oxide(Zn O)nanoparticles.After a detailed introduction to the basic properties of PLA and ZnO nanoparticles,the present review analyzes the main variables that govern the antibacterial activity of PLA-ZnO nanocomposites.Current applications and related manufacturing processes are also presented to showcase the importance of having embedded antibacterial functions in demanding applications such as food packaging and wound dressing.Emphasis is then placed on the emerging literature of the AM of PLA-ZnO nanocomposites,with a focus on fused filament fabrication(also known as fused deposition modeling).Existing gaps and hurdles related to the development and 3D printing of such composites is critically discussed.It is envisioned that a deeper understanding of the processability,thermo-mechanical behavior,biocompatibility and antibacterial efficacy of additively manufactured PLAZnO nanocomposites will foster their adoption in the biomedical field and,ultimately,in all circumstances where it is crucial to limit infection transmission.展开更多
Here,the effects of compatibilization and clay nanoparticles on the gas permeability of nanocomposites of poly-lactic acid(PLA)/thermoplastic starch(TPS)/nanoclay were discussed.TPS and compatibilized PLA/TPS were ta...Here,the effects of compatibilization and clay nanoparticles on the gas permeability of nanocomposites of poly-lactic acid(PLA)/thermoplastic starch(TPS)/nanoclay were discussed.TPS and compatibilized PLA/TPS were tailored in the first step.The starch with D-sorbitol as a plasticizer was mingled through the internal mixer.Afterward,the maleination method was utilized on PLA to ameliorate the compatibilization of PLA and TPS.In this regard,maleic anhydrate(MA)has been grafted on PLA in the presence of L101 as a peroxide initiator via melt mixing to obtain PLA-g-MA.The optimum content of PLAg-MA was about 4 phr,confirmed by DMTA and SEM.Noteworthy,the presence of PLA-g-MA has moderately improved the oxygen barrier.Then,the nanocomposites of PLA and TPS containing 1%of Cloisite-30B as well as the optimum compatibilizer(4phr),were produced by melt mixing in the masterbatch module leading to the formation of an extraordinary well-dispersed structure according to XRD patterns.The mixing order controlled the localization of nanosheets.It was concluded that the inclusion of 1%nanoclay in the PLA phase reduces the oxygen permeability by 55%compared to the pristine blend due to the tortuosity effect of nanosheets that are appropriately dispersed in the matrix.展开更多
Polylactic acid(PLA)-graphene nanocomposites have attracted significant attention in the biomedical field because of their biodegradability,biocompatibility,and excellent mechanical properties.This review provides a c...Polylactic acid(PLA)-graphene nanocomposites have attracted significant attention in the biomedical field because of their biodegradability,biocompatibility,and excellent mechanical properties.This review provides a comprehensive summary of the recent developments in the biomedical applications of PLA/graphene nanocomposites.The discussed applications include tissue engineering,drug delivery,biomedical imaging and sensing,antimicrobial and anticancer treatments,and photothermal and photodynamic therapies.The properties and synthesis of these nanocomposites are also addressed.This review shows that although significant advancements have been made in the development of biomedical applications for PLA/graphene nanocomposites,further research is still required to overcome the existing challenges and limitations,such as improving biocompatibility and biodegradability and optimizing synthesis and processing methods.Despite these challenges,the potential of PLA/graphene nanocomposites in the biomedical field is significant and holds promise for future advancements.展开更多
文摘The aim of this work was to use cellulose nanocrystals that were obtained by hydrolysis in phosphoric acid solution and further modified with succinic anhydride in the microwave field for PLA reinforcement.A series of allbionanocomposites containing unmodified and surface modified cellulose nanocrystals with CNC content in the range of 1–3%_(w.t.) were obtained by melt blending and tested by XRD,SEM,DSC and DMA to investigate the effect of surface esterification of CNCs on the structure,morphology,dynamic mechanical properties of bionanocomposites,as well as phase transitions of PLA in the presence of cellulosic nanofiller.DMA investigations showed the highest increase of storage modulus by ca.7%(335 MPa at 25℃)in the glassy state of PLA for 2%_(w.t.)of unmodified CNC.Though,addition of 2%_(w.t.)of succinylated CNCs caused the highest increase of the onset of glass transition temperature(by 6.2℃)thus widening the temperature range of biocomposite application.The increase of glass transition temperature indicates the strongest interfacial interactions due to improved miscibility of surface modified nanocrystals and thus good dispersion of additive in PLA matrix providing high interface.
文摘In order to extend the usage of PLA-based nanocomposites, the modification of multi-walled carbon nanotubes (MWCNT) and preparation of surfactant modified carbon nanotubes (SMCNT) involved PLA nanocomposites (PLA/SMCNT) were investigated. The morphologies, electrical properties and crystallization behavior of PLA/SMCNT composites were investigated. The TEM images indicated that SMCNTs were dispersed homogenously in the PLA matrix without forming aggregates. The electrical conductivity of PLA/SMCNT was greatly improved and the percolation threshold of PLA/SMCNT was calculated to be 0.61% which is much lower than 1.45% of PLA/MWCNT composite. The crystallization behavior suggested that SDBS together with MWCNT acted as heterogeneous nucleating agent and accelerated the nucleation. Meanwhile, the SMCNT also devoted further restrained effect to spherulites growth due to its well dispersion and improved compatibility with matrix.
基金supported by the Australian Research Council(ARC)through the discovery grant DP210101862supported by the Commonwealth Scientific and Industrial Research Organisation(CSIRO)Research Office through the“Science Leader in Active Materials”grant。
文摘Polymeric biomaterials such as polylactic acid(PLA)play a prominent role in the advancement of biomedical additive manufacturing(AM).PLA offers indeed a very advantageous combination of thermomechanical properties and functional attributes,as it is biobased,biodegradable,biocompatible and easy to print.However,PLA can be damaged by common sterilization methods and is sensitive to most chemical disinfectants,and this may impair its widespread usage.One of the most promising ways to overcome this shortcoming is to provide PLA with embedded antibacterial activity by the addition of appropriate fillers such as zinc oxide(Zn O)nanoparticles.After a detailed introduction to the basic properties of PLA and ZnO nanoparticles,the present review analyzes the main variables that govern the antibacterial activity of PLA-ZnO nanocomposites.Current applications and related manufacturing processes are also presented to showcase the importance of having embedded antibacterial functions in demanding applications such as food packaging and wound dressing.Emphasis is then placed on the emerging literature of the AM of PLA-ZnO nanocomposites,with a focus on fused filament fabrication(also known as fused deposition modeling).Existing gaps and hurdles related to the development and 3D printing of such composites is critically discussed.It is envisioned that a deeper understanding of the processability,thermo-mechanical behavior,biocompatibility and antibacterial efficacy of additively manufactured PLAZnO nanocomposites will foster their adoption in the biomedical field and,ultimately,in all circumstances where it is crucial to limit infection transmission.
基金supported by the National Natural Science Foundation of China[Grant No.51703083]the Project“Fibre materials and products for emergency support and public safety”from Jiangsu New Horizon Advanced Functional Fibre Innovation Center Co.Ltd.[Grant No.2020-fx020026]。
文摘Here,the effects of compatibilization and clay nanoparticles on the gas permeability of nanocomposites of poly-lactic acid(PLA)/thermoplastic starch(TPS)/nanoclay were discussed.TPS and compatibilized PLA/TPS were tailored in the first step.The starch with D-sorbitol as a plasticizer was mingled through the internal mixer.Afterward,the maleination method was utilized on PLA to ameliorate the compatibilization of PLA and TPS.In this regard,maleic anhydrate(MA)has been grafted on PLA in the presence of L101 as a peroxide initiator via melt mixing to obtain PLA-g-MA.The optimum content of PLAg-MA was about 4 phr,confirmed by DMTA and SEM.Noteworthy,the presence of PLA-g-MA has moderately improved the oxygen barrier.Then,the nanocomposites of PLA and TPS containing 1%of Cloisite-30B as well as the optimum compatibilizer(4phr),were produced by melt mixing in the masterbatch module leading to the formation of an extraordinary well-dispersed structure according to XRD patterns.The mixing order controlled the localization of nanosheets.It was concluded that the inclusion of 1%nanoclay in the PLA phase reduces the oxygen permeability by 55%compared to the pristine blend due to the tortuosity effect of nanosheets that are appropriately dispersed in the matrix.
基金Department of Science and Innovation,South Africa,Grant/Award Number:C6A0058National Research Foundation,Grant/Award Number:116083/138768。
文摘Polylactic acid(PLA)-graphene nanocomposites have attracted significant attention in the biomedical field because of their biodegradability,biocompatibility,and excellent mechanical properties.This review provides a comprehensive summary of the recent developments in the biomedical applications of PLA/graphene nanocomposites.The discussed applications include tissue engineering,drug delivery,biomedical imaging and sensing,antimicrobial and anticancer treatments,and photothermal and photodynamic therapies.The properties and synthesis of these nanocomposites are also addressed.This review shows that although significant advancements have been made in the development of biomedical applications for PLA/graphene nanocomposites,further research is still required to overcome the existing challenges and limitations,such as improving biocompatibility and biodegradability and optimizing synthesis and processing methods.Despite these challenges,the potential of PLA/graphene nanocomposites in the biomedical field is significant and holds promise for future advancements.
