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13D printing of bone tissue engineering scaffolds显示文摘Tissue engineering is promising in realizing successful treatments of human body tissue loss that current methods cannot treat well or achieve satisfactory clinical outcomes.In scaffold-based bone tissue engineering,a high performance scaffold underpins the success of a bone tissue engineering strategy and a major direction in the field is to produce bone tissue engineering scaffolds with desirable shape,structural,physical,chemical and biological features for enhanced biological performance and for regenerating complex bone tissues.Three-dimensional(3D)printing can produce customized scaffolds that are highly desirable for bone tissue engineering.The enormous interest in 3D printing and 3D printed objects by the science,engineering and medical communities has led to various developments of the 3D printing technology and wide investigations of 3D printed products in many industries,including biomedical engineering,over the past decade.It is now possible to create novel bone tissue engineering scaffolds with customized shape,architecture,favorable macro-micro structure,wettability,mechanical strength and cellular responses.This article provides a concise review of recent advances in the R&D of 3D printing of bone tissue engineering scaffolds.It also presents our philosophy and research in the designing and fabrication of bone tissue engineering scaffolds through 3D printing.Chong Wang Wei Huang Yu Zhou Libing He Zhi He Ziling Chen Xiao He Shuo Tian Jiaming Liao Bingheng Lu Yen Wei Min Wang 2020Bioactive Materials2020,5,1:20
2Enhanced Poly(ethylene terephthalate)Hydrolase Activity by Protein Engineering显示文摘Poly(ethylene terephthalate)hydrolase(PETase)from Ideonella sakaiensis exhibits a strong ability to degrade poly(ethylene terephthalate)(PET)at room temperature,and is thus regarded as a potential tool to solve the issue of polyester plastic pollution.Therefore,we explored the interaction between PETase and the substrate(a dimer of the PET monomer ethylene terephthalate,2PET),using a model of PETase and its substrate.In this study,we focused on six key residues around the substrate-binding groove in order to create novel high-efficiency PETase mutants through protein engineering.These PETase mutants were designed and tested.The enzymatic activities of the R61A,L88F,and I179F mutants,which were obtained with a rapid cell-free screening system,exhibited 1.4 fold,2.1 fold,and 2.5 fold increases,respectively,in comparison with wild-type PETase.The I179F mutant showed the highest activity,with the degradation rate of a PET film reaching 22.5 mg perμmol·L^-1 PETase per day.Thus,this study has created enhanced artificial PETase enzymes through the rational protein engineering of key hydrophobic sites,and has further illustrated the potential of biodegradable plastics.Yuan Ma Mingdong Yao Bingzhi Li Mingzhu Ding Bo He Si Chen Xiao Zhou Yingjin Yuan 2018Engineering2018,4,6:10
3FUNCTIONAL POLYHYDROXYALKANOATES SYNTHESIZED BY MICROORGANISMS显示文摘Many bacteria have been found to synthesize a family of polyesters termed polyhydroxyalkanoate, abbreviated asPHA. Some interesting physical properties of PHAs such as piezoelectricity, non-linear optical activity, biocompatibility andbiodegradability offer promising applications in areas such as degradable packaging, tissue engineering and drag delivery.Over 90 PHAs with various structure variations have been reported and the number is still increasing. The mechanicalproperty of PHAs changes from brittle to flexible to elastic, depending on the side-chainlength of PHA. Many attempts havebeen made to produce PHAs as biodegradable plastics using various microorganisms obtained from screening naturalenvironments, genetic engineering and mutation. Due to the high production cost, PHAs still can not compete with the non-degradable plastics, such as polyethylene and polypropylene. Various processes have been developed using low cost rawmaterials for fermentation and an inorganic extraction process tbr PHA purification. However, a super PHA production strainmay play the most critical role for any large-scale PHA production. Our recent study showed that PHA synthesis is acommon phenomenon among bacteria inhabiting various locations, especially oil-contaminated soils. This is very importantfor finding a suitable bacterial strain for PHA production. In fact, PHA production strains capable of rapid growth and rapidPHA synthesis on cheap molasses substrate have been found on molasses contaminated soils. A combination of novelproperties and lower cost will allow easier commercialization of PHA for many applications.Peter H.Yu 2000Chinese Journal of Polymer Science2000,18,5:4
4SYNTHESIS OF AN EPOXY-TERMINATED HYPERBRANCHED AROMATIC POLYESTER显示文摘An epoxy-terminated hyperbranched aromatic polyester (P3) was synthesized from a hyperbranched aromaticpolyester containing carboxylic acid end groups (P1), which was derived from the condensation polymerization of the AB2monomer, 5-acetoxyisophthalic acid. Polymer P1 was converted into the polymeric acid chloride by reaction with thionylchloride. The acid chloride was reacted with ethanol and glycidol to form a poly(ethyl ester) (P2) and an epoxy terminatedmaterial (P3), respectively. The reaction conditions in each step of these processes had to be controlled very carefully toavoid unwanted cross-linking reactions. The characterization of products and intermediates, including molecular weightdistributions and thermal properties, are reported.W.J.Feast 2002Chinese Journal of Polymer Science2002,20,6:4
5Synthesis of waterborne polyurethane using snow as dispersant:Structures and properties controlled by polyols utilization显示文摘waterborne polyurethane (WPU) dispersions have gained attention towards environm entally-friendly synthesis. In this article, a series of waterborne polyurethane em ulsions was successfully synthesized and extensively characterized in terms of thermal, mechanical properties, hydrophilic behavior and morphology. Snowwas chosen as dispersant instead of comm only used water. Preparation param eters such as intrinsic properties and molecular weight of polyols were discussed systematically. A chain structure was confirmed by Fourier transform infrared (FT-IR) spectroscopy. when com paring the nature of the polyols (PPG, PEG and PNA, 2000g/mol) of this study, as-synthesized polyether waterborne polyurethane provided higher solid content, viscosity and water-resistance. However, polyester waterborne polyurethane perform ed differently and it exhibited higher therm al stability and crystallinity. When com paring the samples (WPU-N210, WPU-N220, WPU-N230 and WPU-N240) with different molecular weight of the same polyol (PPG) used as soft segment, the emulsion WPU-N220 with molecular weight of 2000g/mol PPG provided the highest solid content and lowest viscosity. It was observed th at particle size was uniform and highly dispersed for all sam ples from TEM images. Therm ogravim etric, differential scanning calorim etry (DSC) and X-ray diffraction results dem onstrated that the emulsion WPU-N230 with m olecular weight of 3000 g/mol PPG possessed higher therm al stability and crystallinity than the other samples. The reason was that the Tg and thermal stability were increased with increasing molecular weight. when molecular weight increased, the arrangem ent of soft segm ent became more regular and so did the regularity of the molecular chains. This work demonstrated that different polyols as soft segment applied could lead to great differences in the structure and property of the resulting WPU.Changqing Fang Shaofei Pan Zhen Wang Xing Zhou Wanqing Lei Youliang Cheng 2019Journal of Materials Science & Technology2019,35,7:4
6Preparation of P(St-NMA)microsphere inks and their application in photonic crystal patterns with brilliant structural colors显示文摘Patterned photonic crystals with structural colors on textile substrates have attracted a special attention due to the great advantages in application,which currently become a research hot-spot.This study utilized an ink-jet printing technology to prepare high-quality photonic crystal patterns with structural colors on polyester substrates.The self-assembly temperature of poly(styrene-N-methylol acrylamide)(P(St-NMA))microspheres set to construct photonic crystals were deeply optimized.Moreover,the structural colors of prepared photonic crystal patterns were characterized and evaluated.When the mass fraction of P(St-NMA)microspheres was 1.0 wt.%,the pH value ranged from 5 to 7,and the surface tension was in the range of 63.79 to 71.20 mN/m,inks could present the best print performance.At 60°C,prepared P(St-NMA)microsphere inks were good for printing to obtain patterned photonic crystals with regular arrangement and beautiful structural colors.Specifically,photonic crystals with different colors could be constructed by regulating the diameter of microspheres in inks,and prepared structural colors exhibited distinct iridescent phenomenon.The present results could provide a theoretical basis for the industrial realization of patterned photonic crystals by ink-jet printing technology.Guojin Liu Pengshuai Han Liqin Chai Peng Lu Yuping He Lan Zhou 2020Frontiers of Materials Science2020,14,1:3
7Converting poly(ethylene terephthalate) waste into N-doped porous carbon as CO_(2) adsorbent and solar steam generator显示文摘Sustainable conversion of waste plastics into valuable carbon materials for diverse applications provides a promising strategy to dispose the municipal and industrial waste plastics.However,it remains a challenge to precisely control the crosslinking reaction for transforming waste polyesters into N-doped porous carbon (NPC) with well-defined microstructures.Herein,we put forwards a strategy of stepwise crosslinking using melamine and ZnCl_(2)/NaCl eutectic salts to convert poly (ethylene terephthalate)(PET) into NPC at 550℃.We prove that firstly melamine reacts with PET degradation products to form a crosslinking structure,and subsequently ZnCl_(2)/NaCl promote the dehydration and decarboxylation of the crosslinking structure to generate a more thermally stable crosslinking structure.The coordination of two tandem crosslinking reactions is critical to control the microstructure of NPC.Without activations,NPC shows large specific surface area of 1173 m~2g^(-1),abundant N dopants,and rich oxygen-containing groups.These combined features endure NPC with excellent performance in CO_(2) capture and solar steam generation,e.g.,high CO_(2) adsorption capacity of 6.47 mmol g^(-1) and evaporation rate of 1.62 kg m^(-2)h^(-1).More importantly,NPC is compared to or prevails over previous carbon-based CO_(2) adsorbents or photothermal materials.This work will advance the research on “green” reutilization of low-cost polyester wastes to prepare sustainable carbon for solar energy conversion,environmental protection,etc.Changyuan Song Boyi Zhang Liang Hao Jiakang Min Ning Liu Ran Niu Jiang Gong Tao Tang 2022Green Energy & Environment2022,7,3:2
8A test study on treatment of high-strength polyester wastewater with anaerobic reactor显示文摘The treatment of polyester wastewater using Up flow activated sludge bed anaerobic filer(UASB AF), demonstrated that UASB AF reactors has a high efficiency, its volume loading is 10~12 kgCOD/(m 3·d),HRT is 22~24 h, and the removal of COD is about 80%. The reactor has advantage of fast starting and enduring pulse loading.韩洪军 陈秀荣 徐春艳 2002Journal of Harbin Institute of Technology(New Series)2002,9,3:2
9Readily Prepared and Tunable Ionic Organocatalysts for Ring-opening Polymerization of Lactones显示文摘Highly potent ionic organocatalyst is developed for room-temperature controlled ring-opening polymerization(ROP)of lactones,includingδ-valerolactone,ε-caprolactone,andδ-hexalactone.The catalysts are prepared by simply mixing tetra-n-butyl ammonium hydroxide and a(thio)urea at elevated temperature under vacuum,and used in cooperation with an alcoholic initiator.The performance of the catalyst is readily adjusted and optimized through variation of the(thio)urea precursor,catalyst composition,and reaction condition.Urea-derived catalysts are generally superior to thiourea-derived ones.Provided with proper N-substituents,the catalyst affords both high polymerization efficiency and high selectivity for monomer enchainment over macromolecular transesterification,even at high monomer conversion and/or substantially extended reaction time.In addition to acidity,structural symmetry of the urea also proves decisive for the catalytic activity,which enables a catalyst-assisted proton transfer process for the ring-opening of lactone and thus provides a novel mechanistic insight for ROP catalyzed by hydrogen-bonding type bifunctional ionic organocatalysts.Zhuo-Lun Jiang Jun-Peng Zhao Guang-Zhao Zhang 2019Chinese Journal of Polymer Science2019,37,12:2
10Mechanical Property and Morphological Analysis of Polyester Composites Reinforced with Cyperuspangorei Fibers显示文摘In the present work,polyester composites reinforced with a newly identified Cyperus pangorei fiber(CPF)were developed by compression moulding technique.The effects of varying fiber content and fiber length on the mechanical properties of the Cyperus pangorei fiber reinforced polyester composites(CPFCs)such as tensile,flexural,and impact properties were studied.Mechanical strength of the CPFCs increased with fiber length up to 40 mm beyond which a reverse trend was observed.Based on the test results,it was concluded that the critical fiber length and the optimum fiber weight percentage were 40 mm and 40 wt%respectively.The maximum increase of 164%and 117%were found for the tensile and flexural strength of the composite with 40 mm fiber length and 40 wt%fiber content,respectively.On the other hand,a 64%increase in impact strength was noticed for the optimum case.The increasing contact surface between the fiber and the polyester matrix in optimum condition can restrict the probability of fiber pullout and in turn can make the composite carry more load.The chemical structure of CPF was also analyzed using Fourier-Transform Infrared Spectroscopy(FTIR)spectrum.The morphological analysis of fractured samples was performed using Scanning Electron Microscopy(SEM)to understand the interfacial bonding between CPFs and polyester matrix.The optimal composite can be a suitable alternative in the field of structural applications in construction and automobile industries.Mayandi Kalimuthu Rajini Nagarajan Alavudeen Azeez Batcha Suchart Siengchin Varada Rajulu Anumakonda Nadir Ayrilmis 2019Journal of Bionic Engineering2019,16,1:2
11梁整加工对Polyester/Lyocell混纺织物强伸性能的研究显示文摘本文研究了Polyester/Lyocell混纺交织织物的耐氧化性、耐碱性、耐高温性能,通过测试处理后织物的断裂强力和断裂伸长率,优化了该织物在印染过程中的工艺路线和工艺参数。朱荣丽 梁高勇 张建春 刘吉平 1999纺织学报1999,20,1:2
12Studies on Isosorbide-enhanced Biodegradable Poly(ethylene succinate)显示文摘To improve the mechanical properties of bio-based poly(ethylene succinate),the sugar monomer isosorbide,whicli is relatively easy to obtain,was used as a copolymerized third monomer to synthesize poly(ethyleneco-isosorbide succinate),a 100%biomass copolyester.The effects of isosorbide on the crystallinity and thermal properties of copolyester were studied by nuclear magnetic resonancefH NMR),differential scanning calorimeter(DSC),and thermogravimetric(TG).Owing to its distinct rigid bicyclic structure,isosorbide can improve the glass transition temperature of the copolyester and decrease the crystallization rate,as well as accelerate the hydrolysis of the copolyester.Simultaneously,the introduction of isosorbide can effectively improve the antistatic properties of copolyester.QU Dezhi ZHANG Fuchen GAO Hongwei WANG Qiuxia BAI Yongping LIU Huihui 2019Chemical Research in Chinese Universities2019,35,2:1
13Improved Polyurethane-coated Orthopedic Casting Bandage for Medical Application显示文摘A new improved polyester casting bandage, which comprises a knitted polyester substrate coated with polyurethane prepolymer, was developed. The appropriate polyester knitted substrate was selected firstly; the optimal ingredient for the synthesis of coating resin (polyurethane prepolymer) was determined then through a series of trial experiments and factorial experiments; the properties of bandage were checked at last. The results of the experiment indicate that most of the properties of the new product could exceed or approximate to the level of similar product of other countries.周荣星 周煜 冯勋伟 2001Journal of Donghua University(English Edition)2001,18,3:1
14Enhanced Thermal Conductivities of Liquid Crystal Polyesters from Controlled Structure of Molecular Chains by Introducing Different Dicarboxylic Acid Monomers显示文摘Enhancing thermal conductivity coefficient (λ) of liquid crystal polyesters would further widen their application in electronics and electricals. In this work, a kind of biphenyl-based dihydroxy monomer is synthesized using 4, 4’-biphenyl (BP) and triethylene glycol (TEG) as raw material, which further reacts with three different dicarboxylic acids (succinic acid, p-phenylenediacetic acid, and terephthalic acid, respectively) by melt polycondensation to prepare intrinsically highly thermally conductive poly 4’, 4”’-[1, 2-ethanediyl-bis(oxy-2, 1-ethanediyloxy)]-bis(p-hydroxybiphenyl) succinate (PEOS), poly 4’, 4”’-[1, 2-ethanediyl-bis(oxy-2, 1-ethanediyloxy)]-bis(p-hydroxybiphenyl) p-phenyldiacetate (PEOP) and poly 4’, 4”’-[1, 2-ethanediyl-bis(oxy-2, 1-ethanediyloxy)]-bis(p-hydroxybiphenyl) terephthalate (PEOT), collectively called biphenyl-based liquid crystal polyesters (B-LCPE). The results show that B-LCPE possess the desired molecular structure, exhibit smectic phase in liquid crystal range and semicrystalline polymers at room temperature, and possess excellent intrinsic thermal conductivities, thermal stabilities, and mechanical properties. λ of PEOT is 0.51 W/(m·K), significantly exceeds that of polyethylene terephthalate (0.15 W/(m·K)) which has similar molecular structure with PEOT, and also higher than that of PEOS (0.32 W/(m·K)) and PEOP (0.38 W/(m·K)). The corresponding heat resistance index (THRI), elasticity modulus, and hardness of PEOT are 174.6℃, 3.6 GPa, and 154.5 MPa, respectively, and also higher than those of PEOS (162.2℃, 1.8 GPa, and 83.4 MPa) and PEOP (171.8℃, 2.3 GPa, and 149.6 MPa).Xiao Zhong Kunpeng Ruan Junwei Gu 2022Research2022,,4:1
15Biosynthesis of Polyhydroxyalkanoates显示文摘Many bacteria are able to synthesize polyhydroxyalkanoates, abbreviated as PHA, as carbon and energy storage compounds. PHA with over 90 different monomer structures has been reported and the number keeps increasing. The piezoelectricity, non linear optical activity, biocompatibility and biodegradability of PHA have offered promising applications in areas such as tissue engineering, drug delivery, smart materials and degradable packaging. Various microorganisms obtained from nature, genetic engineering and mutations have been used for microbial production of PHA as biodegradable plastics. In fact, PHA synthesizing bacteria can be easily found in various locations, especially oil contaminated soils. Many bacterial strains possessing the ability to synthesize PHA with various monomers have been isolated from oil contaminated soils. In molasses contaminated soil, 40% of the isolated bacteria were capable of growing rapidly and synthesizing PHA at the same time. It seems that nature has provided endless numbers of novel PHA synthesizing strains.陈国强 吴琼 陈金春 2001Tsinghua Science and Technology2001,6,3:1
164-Hydroxy-L-Proline as a General Platform for Stereoregular Aliphatic Polyesters:Controlled Ring-Opening Polymerization,Facile Functionalization,and Site-Specific Bioconjugation显示文摘Degradable polyesters have long been regarded as eco-friendly materials,useful for various applicationswhile meeting the growing needs of sustainability.However,it is still challenging to synthesize functional aliphatic polyesters from abundant and cheap renewable sources.Our present study reports a readily available and versatile platform for producing functional and stereoregular aliphatic polyesters from 4-hydroxy-L-proline(4-HYP).We synthesized a bicyclic bridged lactone monomer,namely,NR-PL,by a simple and scalable two-step process allowing facile side-chain functionalization and derivatization.The ring-opening homopolymerization and copolymerization for the generation of N^(R)-PL were controlled fully by using organobases such as 1,8-diazabicyclo[5.4.0]-undec-7-ene(DBU)without any detectable epimerization.This process afforded stereoregular polyesters PNRPE with molar mass(M_(n))up to 90 kg/mol and a narrow dispersity(Ð)generally below 1.10.The uniqueness of the backbone,which contains two chiral centers on a rigid propyl ring,together with the versatility of the side chain,offer tunable properties complementary to existing aliphatic polyesters.The utility of the polymers was showcased by the facile site-specific bioconjugation of PN^(EG3)PE,a water-soluble polyester,to a protein.This work might open numerous opportunities in creating functional and sustainable polyesters for a wide range of applications,including degradable plastics,drug delivery,and protein therapeutics.Jingsong Yuan Dong Shi Yi Zhang Jianhua Lu Letian Wang Er-Qiang Chen Hua Lu 2020CCS Chemistry2020,2,5:1
17Flexural Properties of Weft Knitted Fabric Reinforced Composites显示文摘Several different kinds of weft knitted fabrics from glass fiber yarns were used as reinforcement to make fabric/polyester composite laminates. Flexural tests were carried out to examine stress- deflection process and compare the mechanical properties in course and wale directions of these composites. The experimental results indicate that the numbers of load-bearing yarn in course and wale direction and the fabric density are the main factors influencing the ultimate tensile strength and initial elastic modulus of specimens.Long Hairu(龙海如) Feng Xunwei(冯勋伟) 2001Journal of Donghua University(English Edition)2001,18,4:1
18STUDY OF PET AIR-JET TEXTURING SEWING THREAD PROPERTIES显示文摘This paper presents a study of properties of air-jet textured threads made from high strengthpolyester filament and ordinary strength polyester filament.It includes the evaluation of tenacity,breaking elongation,modulus,specific work,evenness,abrasion resistance,hook strength,knotstrength and other mechanical properties relating to sewing.The polyester air-jet texturing sewingthread has special structure and appearance and possesses better properties of evenness,goodabrasion resistance,fatigue property,high hook and knot strength.Mohamed Amin Yousef 曲军峰 严灏景 王善元 1991Journal of China Textile University(English Edition)1991,9,4:1
19Progress in Researches on Biodegradable Starch-Based Materials显示文摘As one type of environment-friendly polymer,biodegradable starch-based materials have been widely explored in recent years and considered one of the most promising plastics in the future. Currently,either synthetic biodegradable aliphatic polyesters or certain natural polymers are usually blended with thermoplastic starch to enhance hydrophobicity and service performance of starch-based materials. The main deficiency lies in the low compatibility between starch and polyester phases. Therefore amphiphilic compatibilizers,such as hydroxyl functioned polyesters,need to be developed in the future. Moreover,multi-phase blending systems including two or more polyester phases are also supposed to be designed.张青山 宁卓远 李云政 2010Journal of Beijing Institute of Technology2010,19,2:1
20A brief review on development and application of insulating materials in China (Part 2) Synthetic film, paper and composite material显示文摘Besides polyamidimide film and aromatic polyamidefiber paper which have been mentioned before, wehave also developed several other kinds of synthetic film and paperas polyester film, polyester fibre felt, polypropene film, and theircomposite materials. (a) Polyester film was exploited in China in early 60’s andput into mass production in middle 60’s. It is used mainly for slotinsulation of medium and small size motors as class EWU Weizheng China Electrotechnical Society 1992Electricity1992,,2:0
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