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Influences of poly (vinyl alcohol) molecular weight and carbon nanotubes on radiation crosslinking Shape memory polymers

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Progress in Natural Science:Materials International 2017年第3期27卷 316-325页

作者： Aamer A.M.Alfayyadh S.Lotfy A.A.Basfar Mutasim I.Khalil Radiation Technology Center Nuclear Science Research InstituteKing Abdulaziz City for Science and Technology(KACST) Polymer Chemistry Department National Center for Radiation Research and TechnologyAtomic Energy Authority Department of Chemistry Faculty of ScienceKing Saud University

Polyvinyl alcohol（PVA） of two molecular weights was used to prepare Shape memory polymers based on chemical-crosslinking by glutaraldehyde.The chemical-crosslinking was done in the presence of 2-carboxyethvl acrylate oligomers（CEA） and nano-filler[multi-wall carbon nanotubes（MWCNT） and functionalized carbon nanotubes（MWCNT-NH;）]followed by radiation-induced crosslinking.The analysis of the material revealed an increase in the gel fraction and a significant reduction in swelling of the nanocomposite material that was crosslinked with both glutaraldehyde and ionizing radiation.The radiation crosslinked nanocomposites demonstrated approximately a 90%gelation over a range of 50-300 kGy irradiation doses.The scanning electron microscopy（SEM） analysis showed a homogeneous distribution of nanocomposites in the composite matrix.The thermal properties of radiation crosslinked（PVA/CEA） and（PVA-CEA）-nano-fillers were investigated by a thermogravimetric analysis（TGA）.The mechanical properties were examined via dynamic mechanical analysis（DMA） which showed significant variation because of the addition of nanocomposites.This radiation crosslinked materials show good shape memory behavior that may be useful in many applications based on the range of temperatures at which Tan 8 appears.

关键词： Shape memory polymers Radiation Poly(vinyl alcohol) Nanocomposite materials

A thermoviscoelastic finite deformation constitutive model based on dual relaxation mechanisms for amorphous Shape memory polymers

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International Journal of Smart and Nano Materials 2023年第2期14卷 243-264页

作者： Hao Duan Jianping Gu Hao Zeng Akbar A.Khatibi Huiyu Sun State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjingChina Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology School of Materials Science and EngineeringNanjing Institute of TechnologyNanjingChina School of Physical and Mathematical Sciences Nanjing Tech UniversityNanjingChina School of Engineering Royal Melbourne Institute of TechnologyMelbourneAustralia

This paper proposes a new thermoviscoelastic finite deformation model incorporating dual relaxation mechanisms to predict the complete thermo-mechanical response of amorphous Shape memory polymers.The model is underpinned by the detailed microscopic molecular mechanism and effectively reflects the current understanding of the glass transition phenomenon.Novel evolution rules are obtained from the model to characterize the viscous flow,and a new theory named an internal stress model is introduced and combined with the dual relaxation mechanisms to capture the stress recovery.The rationality of the constitutive model is verified as the theoretical results agree well with the experimental data.Moreover,the constitutive model is further simplified to facilitate engineering applications,and it can roughly capture the characteristics of Shape memory polymers.

关键词： Shape memory polymers constitutive model dual relaxation mechanisms viscous flow rules internal stress model

Sustainable Shape memory polymers based on epoxidized natural rubber cured by zinc ferulate via oxa-Michael reaction

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International Journal of Smart and Nano Materials 2015年第4期6卷 195-210页

作者： Xuhui Zhang Tengfei Lin Zhenghai Tang Kailun Sun Baochun Guo Department of Polymer Materials and Engineering South China University of TechnologyGuangzhou 510640P.R.China

Although various Shape memory polymers(SMPs)or diverse applications have been widely reported,the SMPs based on rubbers have been rarely realized due to the low triggering temperature of rubbers.In another aspect,the SMPs based on sustainable substances are highly desired for the growing shortage in fossil resources.In the present study,we accordingly developed the sustainable SMPs with tunable triggering temperature,based on natural rubber(NR)and ferulic acid(FA)as the raw materials.Specifically,the SMPs are based on a crosslinked network of epoxidized natural rubber(ENR)crosslinked by in situ formed zinc ferulate(ZDF)via oxa-Michael reaction.The excellent shape memory effect(SME)is found in these SMPs,as evidenced by the high fixity/recovery ratio and the tunable triggering temperature.With the incorpora-tion of natural halloysite nanotubes(HNTs),the stress and recovery rate of the SMPs are found to be tunable,which widens the application of this kind of SMPs.The combination of adoption of sustainable raw materials,and the excellent and tunable SME makes these SMPs potentially useful in many applications,such as various actuators and heat-shrinkable package materials.

关键词： Shape memory polymers epoxidized natural rubber ferulic acid oxa-Michael reaction sustainable

Switchable shape memory polymer bio-inspired adhesive and its application for unmanned aerial vehicle landing

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Chinese Journal of Aeronautics 2024年第3期37卷 380-390页

作者： Qingsong HE Zefang ZHAO Qiyun ZHONG Siyuan LIU Kai DENG Yongqi LIU Ning ZHANG Zijie ZHAO Fengjiang ZHAN Jianfeng ZHAO Jiangsu Provincial Key Laboratory of Bionic Functional Materials College of Mechanical and Electrical EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Advanced Technology for Small and Medium-Sized UAV Ministry of Industry and Information TechnologyUnmanned Aerial Vehicles Research InstituteNanjing University of Aeronautics and AstronauticsNanjing 210016China State Key Laboratory of Mechanics and Control of Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Functional Morphology and Biomechanics Institute of ZoologyKiel UniversityKiel 24098Germany

Controlled and switchable adhesion is commonly observed in biological systems.In recent years,many scholars have focused on making switchable bio-inspired adhesives.However,making a bio-inspired adhesive with high adhesion performance and excellent dynamic switching properties is still a challenge.A shape memory Polymer Bio-inspired Adhesive(SMPBA)was successfully developed,well realizing high adhesion(about 337 kPa),relatively low preload(about90 kPa),high adhesion-to-preload ratio(about 3.74),high switching ratio(about 6.74),and easy detachment,which are attributed to the controlled modulus and contact area by regulating temperature and the shape memory Effect(SME).Furthermore,SMPBA exhibits adhesion strength of80–337 kPa on various surfaces(silicon,iron,and aluminum)with different roughness(Ra=0.021–10.280)because of the conformal contact,reflecting outstanding surface adaptability.The finite element analysis verifies the bending ability under different temperatures,while the adhesion model analyzes the influence of preload on contact area and adhesion.Furthermore,an Unmanned Aerial Vehicle(UAV)landing device with SMPBA was designed and manufactured to achieve UAV landing on and detaching from various surfaces.This study provides a novel switchable bio-inspired adhesive and UAV landing method.

关键词： Bio-inspired adhesive Shape memory polymers Switchable adhesive Unmanned aerial vehicle Landing

Advances in orthodontic clear aligner materials

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Bioactive Materials 2023年第4期22卷 384-403页

作者： Yashodhan M.Bichu Abdulraheem Alwafi Xiaomo Liu James Andrews Bjorn Ludwig Aditi Y.Bichu Bingshuang Zou Private Practice Abu DhabiUnited Arab Emirates Department of Oral Health Science Faculty of DentistryUniversity of British ColumbiaVancouverCanada Faculty of Dentistry Department of Dental Public HealthKing Abdulaziz UniversityJeddahSaudi Arabia Department of Orthodontics Peking University School and Hospital of StomatologyBeijingChina Private Practice PerthAustralia Department of Orthodontics University of HomburgSaarGermany

Rapid technological improvements in biomaterials,computer-aided design(CAD)and manufacturing(CAM)have endorsed clear aligner therapy(CAT)as a mainstay of orthodontic treatment,and the materials employed for aligner fabrication play an all-important role in determining the clinical performance of clear aligners.This narrative review has attempted to comprehensively encompass the entire gamut of materials currently used for the fabrication of clear aligners and elucidate their characteristics that are crucial in determining their performance in an oral environment.Historical developments and current protocols in aligner fabrication,features of contemporary bioactive materials,and emerging trends related to CAT are discussed.Advances in aligner material chemistry and engineering possess the potential to bring about radical transformations in the therapeutic applications of CAT;in the absence of which,clear aligners would continue to underperform clinically,due to their inherent biomechanical constraints.Finally,while innovations in aligner materials such as Shape memory polymers,direct three-dimensional(3D)printed clear aligners and bioactive materials combined with clear aligner materials are essential to further advance the applications of CAT;increased awareness of environmental responsibilities among aligner manufacturers,aligner prescribing clinicians and aligner users is essential for better alignment of our climate change goals towards a sustainable planet.

关键词： Clear aligners Bioactive materials Shape memory polymers Direct 3D printing Environment Review

Mechanical properties and shape memory behavior of 4D printed functionally graded cellular structures

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Science China(Technological Sciences) 2023年第12期66卷 3522-3533页

作者： ZENG ChengJun LIU LiWu ZHAO Wei LIU ZhengXian XIN XiaoZhou LIU YanJu LENG JinSong Department of Astronautical Science and Mechanics Harbin Institute of TechnologyHarbin 150001China Center for Composite Materials and Structures Harbin Institute of TechnologyHarbin 150080China

The properties of functionally graded(FG) cellular structures vary spatially, and the varying properties can meet the requirements of different working environments. In this study, we fabricated FG cellular structures with shape memory effect by 4D printing and evaluated the compressive performance and shape memory behavior of these structures with temperature through experimental analysis and finite element simulations. The results show that the maximum energy absorption gradually decreases but the compressive modulus gradually increases with increasing gradient parameters. Moreover, the finite element simulations also show that the compressive deformation mode of the structure shifts from uniform to non-uniform deformation with increasing gradient parameters. The compressive modulus and compressive strength of 4D printed FG structures decrease with increasing temperature due to the influence of the shape memory polymer, and they exhibit outstanding shape recovery capability under high-temperature stimulus. The proposed 4D printed FG structures with such responsiveness to stimulus shed light on the design of intelligent energy-absorbing devices that meet specific functional requirements.

关键词： functionally graded structures 4D printing Shape memory polymers energy absorption cellular structures

Photo-responsive shape memory polymer composites enabled by doping with biomass-derived carbon nanomaterials

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Nano Research 2022年第2期15卷 1383-1392页

作者： Nina Yan Zhiyu Zheng Yunliang Liu Xizhi Jiang Jiamin Wu Min Feng Lei Xu Qingbao Guan Haitao Li Institute of Agricultural Facilities and Equipment Jiangsu Academy of Agricultural SciencesKey Laboratory for Protected Agricultural Engineering in the Middle and Lower Reaches of Yangtze RiverMinistry of Agriculture and Rural AffairsNanjing 210014China Institute for Energy Research School of Chemistry and Chemical EngineeringJiangsu UniversityZhenjiang 212013China State Key Laboratory for Modification of Chemical Fibers and Polymer Materials International Joint Laboratory for Advanced Fiber and Low-dimension MaterialsCollege of Materials Science and EngineeringDonghua UniversityShanghai 201620China

As photothermal conversion agents,carbon nanomaterials are widely applied in polymers for light-triggered shape memory behaviors on account of their excellent light absorption.However,they are usually derived from non-renewable fossil resources,which go against the demand for sustainable development.Biomass-derived carbon nanomaterials are expected as alternatives if they are designed with good dispersibility as well as splendid photothermal properties.Up to date,very few researches focused on this area.Herein,we report a novel light-triggered shape memory composite by incorporating renewable biomass-derived carbon nanomaterials into acrylate polymers without deep purification and processing.These functionalized carbon nanomaterials not only have stable dispersion in polymers as fillers,but also can endow the polymers with excellent and stable thermal and photothermal responsive properties in biological friendly environment.With the introduction of biomass-derived carbon nanomaterials,the mechanical properties of the composites are also further enhanced with the formation of hydrogen bonding between the carbon nanomaterials and the polymers.Notably,the doping of 1%carbon nanomaterials endows the polymer with sufficient hydrogen bonds that not only exhibit excellent thermal and photothermal responsive properties,but also with enough space for the motion of chains.These properties make such composite a promising and safe candidate for shape memory applications,which provide a new avenue in smart fabrics or intelligent soft robotics.

关键词： biomass carbon nanomaterials Shape memory polymers thermal responsive photothermal responsive

Nanocomposite electrospun fibers of poly(ε-caprolactone)/bioactive glass with shape memory properties

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Bioactive Materials 2022年第5期7卷 230-239页

作者： Liliana Liverani Anna Liguori Paola Zezza Chiara Gualandi Maurizio Toselli Aldo R.Boccaccini Maria Letizia Focarete Department of Materials Science and Engineering University of Erlangen-NurembergCauerstr.691058ErlangenGermany Department of Chemistry“Giacomo Ciamician”and INSTM UdR of Bologna University of Bolognavia Selmi 240126BolognaItaly Interdepartmental Center for Industrial Research on Advanced Applications in Mechanical Engineering and Materials Technology CIRI-MAMUniversity of BolognaViale Risorgimento240136BolognaItaly Department of Industrial Chemistry“Toso Montanari” University of BolognaViale Risorgimento 440136BolognaItaly Health Sciences and Technologies–Interdepartmental Center for Industrial Research(HST-ICIR) Alma Mater Studiorum-Universit`a di Bologna40064Ozzano dell’EmiliaBolognaItaly

Electrospun fibers of shape memory triethoxysilane-terminated poly(epsilon-caprolactone)(PCL-TES)loaded with bioactive glasses(BG)are here presented.Unloaded PCL-TES,as well as PCL/BG nanocomposite fibers,are also considered for comparison.It is proposed that hydrolysis and condensation reactions take place between triethoxysilane groups of the polymer and the silanol groups at the BG particle surface,thus generating additional crosslinking points with respect to those present in the PCL-TES system.The as-spun PCL-TES/BG fibers display excellent shape memory properties,in terms of shape fixity and shape recovery ratios,without the need of a thermal crosslinking treatment.BG particles confer in vitro bioactivity to PCL-based nanocomposite fibers and favor the precipitation of hydroxycarbonate apatite on the fiber surface.Preliminary cytocompatibility tests demonstrate that the addition of BG particles to PCL-based polymer does not inhibit ST-2 cell viability.This novel approach of using bioactive glasses not only for their biological properties,but also for the enhancement of shape memory properties of PCL-based polymers,widens the versatility and suitability of the obtained composite fibers for a huge portfolio of biomedical applications.

关键词： PCL-TES Bioactive glasses Bioactivity Shape memory polymers Electrospinning Benign solvents

Photothermal and pH dual-responsive self-healing coating for smart corrosion protection

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Journal of Materials Science & Technology 2022年第12期107卷 34-42页

作者： Yao Huang Panjun Wang Weimin Tan Wenkui Hao Lingwei Ma Jinke Wang Tong Liu Fan Zhang Chenhao Ren Wei Liu Dawei Zhang Beijing Advanced Innovation Center for Materials Genome Engineering Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China National Materials Corrosion and Protection Data Center University of Science and Technology BeijingBeijing 100083China National Engineering Research Center for Coatings CNOOC Changzhou Paint and Coatings Industry Research InstituteChangzhou 213016China State Key Laboratory of Advanced Power Transmission Technology(Global Energy Interconnection Research Institute Co.Ltd. )Beijing 100083China BRI Southeast Asia Network for Corrosion and Protection(MOE) Shunde Graduate School of University of Science and Technology BeijingFoshan 528300China

A novel self-healing coating with photothermal and pH dual-responsive properties has been designed to protect carbon steel against corrosion by loading the stimuli-responsive microcapsules into a shape memory epoxy coating. The sandwich-like microcapsules were based on reduced graphene oxide/mesoporous silica(r GO@MS) assembled with a p H-responsive poly(N,N-dimethylaminoethyl methacrylate)(PDMAEMA) layer, and were loaded with benzotriazole(BTA) inhibitors(abbreviated as rGO@MS-P-BTA). Under near-infrared(NIR) light irradiation, the prominent photothermal effect of rGO could not only elevate the coating temperature to activate the shape memory effect and close the coating scratch, but also facilitate the release of corrosion inhibitors to suppress the corrosion activity. Moreover,the PDMAEMA as a p H-driven “gatekeeper” realized the controlled release of BTA from microcapsules at acid conditions. The surface morphology analysis, electrochemical impedance spectroscopy(EIS), and scanning electrochemical microscopy(SECM) were performed to evaluate the self-healing performance of the composite coatings. The results showed that the combination of NIR light and p H-responsive selfhealing effects endowed the coating with short healing time and prominent healing efficiency.

关键词： Self-healing coatings Corrosion inhibitors Photothermal effects pH-responsive Shape memory polymers