A theoretical model for impact protection of flexible polymer material

The relationship between the protective performance of flexible polymer material and material parameters(elasticmodulus,viscosity coefficient)is explored,an impact collision motion equation between two bodies is establishedfrom the viscoelastic material constitutive,and the relationship between the kinematic response and the materialparameters is obtained.Based on the Kelvin constitutive model,a theoretical model for impact between the pro-tective body and the protected body is established,then the dynamic response is obtained.The feasibility of themodel was verified by drop hammer experiment,and the material parameters(elastic modulus,viscosity coeffi-cient)were obtained by formula.The model is discretized and the relationship between local impact response andmaterial parameters is analyzed.The discussion results on the relationship between the impact response and theprotective material performance indicate that adjusting the elastic modulus,viscosity coefficient,and thicknessof the protective material can effectively improve protective effect.

A Research on the Air Permeability of High Polymer Materials Used to Produce Sports Clothing Fabrics

Composite fabrics based on Polytetrafluoroethylene(PTFE)polymer displays several notable properties.They are waterproof,windproof,permeable to moisture and thermally insulating at the same time.In the present study,PTFE fibers are used as raw material to make fiber membranes.The film is formed by crisscrossing interconnected fiber filaments and the related air permeability:tensile creep characteristics and other properties are tested.The results show that the pore size,thickness,and porosity of the film itself can affect the moisture permeability of the film.The water pressure resistance of the selected fabric is 8.5 kPa,and the moisture permeability is 7038 g/(m^(2)·24 h).

New Nano Polymer Materials for Composite Exterior-Wall Coatings

A triethylenetetramine epoxy mixture was synthesized through the reaction of a low-molecular-weight liquid epoxy resin with triethylenetetramine(TETA).Then triethyltetramine(TETA)was injected dropwise into a pro-pylene glycol methyl ether(PM)solution for chain extension reaction.A hydrophilic andflexible polyether seg-ment was introduced into the hardener molecule.The effects of TETA/DGEPG,reaction temperature and reaction time on the epoxy conversion of polyethylene glycol diglycidyl ether(DGEPG)were studied.In addition,several alternate strategies to add epoxy resin to the high-speed dispersion machine and synthesize MEA DGEBA adduct(without catalyst and with bisphenol A diglycidyl ether epoxy resin)were compared.It was found that the higher the molecular weight of triethylenetetramine,the longer the chain segment of the surface active molecule.When the equivalence ratio of amine hydrogen and epoxy group is low,the stability of lotion is good.When the ratio of amine hydrogen to epoxy group is large,the content of triethylenetetramine is small.The main objective of this study is the provision of new data and knowledge for the development of new materials in the coating and electronic industry.

Synthesis, Characterization of A Novel Polymeric Reaction Monomer for Preparing Highly Fluorescent Rare Earth Polymer Materials

A novel polymeric reaction monomer (NPRM) for preparing highly fluorescent rare earth polymer materials was synthesized via interface and coordinating reaction. The composition and structure of the NPRM and intermediate product (ligand) were characterized through the Fourier transform infrared spectroscopy (FT-IR), carbon-nuclear magnetic resonance spectrum (13CNMR), Mass spectra (MS), and element analysis data. The results showed that the composition and structure of NPRM agreed with that of anticipated product. The NPRM was composed of two important sections. Section 1 was able to provide excellent fluorescent properties for final rare earth polymer material through the effect energy transfer between ligand and rare earth ion; Section 2 would endow with the NPRM excellent polymeric active and form highly fluorescent rare earth polymer material. Fluorescent properties of the NPRM were also researched via a CARY ECLIPSE fluorescent spectrometer. The results showed that the NPRM possessed excellent luminescent properties. The corresponding emission peaks based on the 5D0→7F1(601.6 nm), 5D0→7F2(625.0 nm), 5D0→7F3(660.5 nm) and 5D0→7F4(706.3 nm) transitions for Eu3+ were observed. The strongest emission peak was at 625 nm, which belonged to 5D0→7F2 transition.

Research on the Teaching Reform of Polymer Materials Foundation Course-Based on the Case Analysis Method

In today's education and teaching reform,the traditional teaching method in the teaching of polymer materials has been gradually replaced with various new teaching methods.Among them,the case analysis method is a very efective teaching method,which has been applied to the teaching of polymer materials.Through example-based teaching,students 125 participation can be effectively improved,and their theoretical knowledge can be fully utilized.This would have a positive role in promoting the improvement of students'knowledge system and their learning ability.In regard to this,this article analyzes the application of case analysis in the teaching of polymer materials so as to improve its efficiency and quality.

Synthesis of stimuli-responsive pillararene-based supramolecular polymer materials for the detection and separation of metal ions

A stimuli-responsive supramolecular polymer network(G-(CN)_(2)⊂BXDSP5)with aggregation-induced emission(AIE)properties has been efficiently constructed by host-guest interactions between pillar[5]arene derivative BXDSP5 and a homoditopic guest G-(CN)_(2),which shows not only excellent fluorescence properties due to the AIE effect but also desirable ion-sensing abilities in both solution and solid states,holding great potential in the applicable fluorescence detection for Fe^(3+).The resultant G-(CN)_(2)⊂BXDSP5 can be transformed into supramolecular polymer gel at high concentration via multiple noncovalent interactions,showing multi-stimuli-responsiveness in response to temperature change,mechanical force,and competitive agent.Meanwhile,the xerogel of supramolecular polymer material has been successfully used to remove Fe^(3+)from water with high adsorption efficiency.In addition,an ionresponsive film based on supramolecular polymer has also been developed,which can serve as a practical and convenient fluorescence test kit for detecting Fe^(3+).

Advanced polymer materials-based electronic skins for tactile and non-contact sensing applications

Recently,polymer materials have been at the forefront of other materials in building high-performance flexible electronic skin(e-skin)devices due to con-spicuous advantages including excellent mechanical flexibility,good compatibil-ity,and high plasticity.However,most research works just paid considerable attention and effort to the design,construction,and possible application of e-skins that reproduce the tactile perception of the human skin sensory system.Compared with tactile sensing devices,e-skins that aim to imitate the non-contact sensing features in the sensory system of human skin tend to avoid undesired issues such as bacteria spreading and mechanical wear.To further promote the development of e-skins to the human skin sensory system where tactile perception and non-contact sensing complement each other,significant progress and advances have been achieved in the field of polymer materials enabled e-skins for both tactile perception and non-contact sensing applications.In this review,the latest progress in polymer material-based e-skins with regard to tactile,non-contact sensing capabilities and their practical applications are introduced.The fabrication strategies of polymer materials and their role in building high-performance e-skins for tactile and non-contact sensing are highlighted.Furthermore,we also review the research works that integrated the polymer-based tactile and non-contact e-skins into robots and prostheses,smart gloves,and VR/AR devices and addressed some representative problems to dem-onstrate their suitability in practical applications in human–machine interac-tions.Finally,the current challenges in the construction of high-performance tactile and non-contact e-skins are highlighted and promising properties in this direction,by taking advantage of the polymer materials,are outlined.

Research Progress on the Preparation of Inorganic/Natural Materials Composite Microspheres

Microspheres are a new type of drug carrier with great potential for development and application.Natural polymers have good biocompatibility,biodegradability,and are easily dispersed in living organisms,making them suitable for preparing microspheres.Inorganic materials(mainly inorganic minerals)have excellent mechanical properties and are inexpensive and easy to obtain.Through the coupling and hybridization of natural polymers and inorganic materials,they can complement each other's advantages and synergistically enhance efficiency,resulting in many excellent physical and chemical properties.Inorganic materials/natural polymer composite microspheres can be prepared by modifying natural polymers with inorganic materials through various methods such as emulsification crosslinking,solution mixing,in-situ synthesis,extrusion,etc.The application of inorganic materials/natural polymer composite microspheres in drug delivery systems has significant sustained-release effects,is safe and non-toxic,and the cost of carrier materials is relatively low,which has certain significance for the development of new drug carriers.This article reviews the recent research on the preparation,drug loading and release properties of inorganic material/natural polymer composite microspheres,analyzes the advantages and disadvantages of commonly used preparation methods,and looks forward to the development direction of composite microspheres.

An Intelligent Manufacturing Platform of Polymers:Polymeric Material Genome Engineering

Polymeric materials with excellent performance are the foundation for developing high-level technology and advanced manufacturing.Polymeric material genome engineering(PMGE)is becoming a vital platform for the intelligent manufacturing of polymeric materials.However,the development of PMGE is still in its infancy,and many issues remain to be addressed.In this perspective,we elaborate on the PMGE concepts,summarize the state-of-the-art research and achievements,and highlight the challenges and prospects in this field.In particular,we focus on property estimation approaches,including property proxy prediction and machine learning prediction of polymer properties.The potential engineering applications of PMGE are discussed,including the fields of advanced composites,polymeric materials for communications,and integrated circuits.

Durability Testing of Composite Aerospace Materials Based on a New Polymer Carbon Fiber-Reinforced Epoxy Resin

In this study,the durability of a new polymer carbonfiber-reinforced epoxy resin used to produce composite material in the aerospacefield is investigated through analysis of the corrosion phenomena occurring at the microscopic scale,and the related infrared spectra and thermal properties.It is found that light and heat can con-tribute to the aging process.In particular,the longitudinal tensile strength displays a non-monotonic trend,i.e.,itfirst increases and then decreases over time.By contrast,the longitudinal compressive and inter-laminar shear strengths do not show significant changes.It is also shown that the inter-laminar shear strength of carbonfiber/epoxy resin composites with inter-laminar hybrid structure is better than that of pure carbonfiber materials.The related resistance to corrosion can be improved by more than 41%.

Basic Characteristics of an Appropriate Waste Fillers for Solvent Free and Water-Borne Industrial Polymer Floors and Their Utilization

Recently the manufacture of epoxy coating and flooring materials begun to be under strong pressure to use more environmentally friendly raw materials in its composition.First tendency to reduce of solvents and diluents contained in the materials appeared at the end of 90´s.This situation was supported by the Council of Europe in 2004 to reduce VOC emissions to zero till 2020.Solvent materials were thus largely replaced by solvent free materials from which the volatile substances are not released into the air.But pressure continued to increase,and over the past decade began to take centre stage water-based epoxy.On the Czech market solvent based material is still occasionally used,but predominant are solvent free materials.There are no commonly used materials containing wastes as fillers in new water-borne and solvent-free epoxy materials.Characteristics identification of the waste material as a potential filler is a set of properties that determine the limits of secondary raw materials or waste as a filler.This paper describes the basic characteristics which must be selected to meet the requirements,to affect negatively the workability,sedimentation,properties and behavior of the final floor system.Some materials must comply with special requirements,such as resistance to chemicals,etc.Next part of paper talks about utilization of polymer floors and their mechanical properties.

Combined effect of the use of carbon fiber and seawater and the molecular structure on the tribological behavior of polymer materials

The combined effect of the use of carbon fiber and seawater and the molecular structure on the tribological behavior of various polymer materials under natural seawater lubrication was investigated. After the investigation, the wear morphology of the contact surface was observed by a laser scanning confocal microscope, and the texture of the wear scars and tracks were presented in 3 D profiles. Moreover, the mechanism of mixed lubrication and wear resistance was analyzed. The results demonstrated that the friction coefficient of carbon fiber-reinforced polyetheretherketone(CFRPEEK) is the lowest and fluctuates at approximately 0.11. Moreover, the seven polymer materials in ascending order of friction coefficients are CFRPEEK, carbon fiber-reinforced polyamide-imide, polytetrafluoroethylene, polyoxymethylene, polyetheretherketone(PEEK), acrylonitrile butadiene styrene resin, and glass fiber–epoxy resin. More critically, the simultaneous incorporation of deposition, polymeric scrap, hydrophilic groups, and seawater resulted in a decrease in the friction and wear of polymer materials under seawater lubrication. This observation implies that a synergistic friction-reducing and wear-resistant effect exists between carbon fiber, seawater, and the molecular structure of PEEK. As a result, a highly effective polymer material was discovered, CFRPEEK, which has the lowest friction coefficient of 0.11 and lowest wear rate of 2 × 10^(–5) mm^3?(N?m)^(-1) among the polymer materials; this validates the selection of dual friction pairs for seawater hydraulic components.

Specific biotests to assess eco-toxicity of biodegradable polymer materials in soil

Eco-toxicity investigation of polymer materials was considered extremely necessary for their potential menace,which was widely use as mulching materials in agricultural.In this study,polyethylene(PE),polystyrene(PS)and synthetic biomaterials-Ecoflex and cellulose were applying into soil cultivated with two potential indicator plants species:oat(A v ena sati v a)and red radish(Raphanus sativum).Variety of chemical,biochemical parameters and enzyme activity in soil were proved as effective approach to evaluate polymers phytotoxicity in plant-soil mesocosm.The F-value of biomass,pH,heavy metal and electoral conductivity of Raphanus behaved significant different from T0.Significant analysis results indicated biodegradation was fast in PE than PS,besides,heavy metals were dramatically decrease in the end implied the plant absorption may help decrease heavy metal toxicity.The increase value at T2 of Dehydrogenase activity(0.84 higher than average value for Avena&0.91 higher for Raphanus),Metabolic Index(3.12 higher than average value for Avena&3.81 higher for Raphanus)means during soil enzyme activity was promoted by biodegradation for its heterotrophic organisms’energy transportation was stimulated.Statistics analysis was carried on Biplot PC1(24.2%of the total variance),PC2(23.2%of the total variance),versus PC3(22.8%of the total variance),which indicated phosphatase activity and metabolic index was significant correlated,and high correlation of ammonium and protease activity.Furthermore,the effects were more evident in Raphanus treatments than in Avena,suggesting the higher sensitivity of Raphanus to polymers treatment,which indicate biodegradation of polymers in Raphanus treatment has produced intermediate phytotoxic compounds.

A comparative analysis of dielectric properties of oil-paper insulation and polymer materials before and after thermal aging

The shortcomings of oil-immersed transformer solid insulation like low high-temperature resistance of the insulation paper and the uneven distribution of electric field caused by the large difference of dielectric constants between insulation paper and transformer oil,restricted the development of transformer with smaller size and larger capacity.In view of this situation and the transformer’s demand for the dielectric physicochemical and mechanical property of insulation material,polycarbonate,polyester film and polyphenylene sulfide with high high-temperature resistance were chosen for the comparison analysis in this paper We did the 300-day thermal aging experiment on four samples in transformer oil under different aging temperatures of90°C,110°C and 130°C,then analyzed the changes of their dielectric properties.The experiment results are as follows;the permittivity and dielectric dissipation factor of the three polymer materials are apparently smaller than those of the paper both before and after 300-day aging;the volume resistivity and partial discharge inception voltage of the three materials are higher than those of the paper both before and after aging;and the breakdown field strength of polycarbonate is higher than that of the paper both before and after aging,while that of polyester film and polyphenylene sulfide are slightly lower than that of the paper.

Virtual special issue:Organic and polymer materials for electronics

Welcome to this virtual special issue focusing on organic and polymer materials for electronics published in Chinese Chemical Letters since 2017. For more than a century, people have always believed that organic compounds cannot be well employed for electronic conducting. Till 2000,Heeger,MacDiarmid and Shirakawa were acknowledged by the Nobel Prize of chemistry for

Development of Polymer Materials for Combating Desertification

Aiming respectively at the two problems in desertiflcation areas, namely water shortage and serious soil erosion, the polymer materials for combating desertiflcation may be classified as water absorbing-retaining polymers (WARPs) and sandy soil stabilizing polymers (SSSPs). Their further classifications and current researcfl situations were introduced. It is suggested that the major hindrancefor their wide appHcation is the high cost. The authors' newest research resuits on cutting cost and enhancing ef...

Compressive Strength of Polymer Grouting Material at Different Temperatures

In order to study the influence of temperature on compressive strength of polymer grouting material,the compression specimen injection mold is self-made,and the uniaxial compressive test was carried out in the temperature control box under different temperatures.The change regularity of compressive strength of polymer grouting material under different temperatures and the law of volume changes of polymer samples were obtained.The experimental results show that：the compressive strength of polymer material increases with the increase of density;the temperature change has a certain influence on the compressive strength of polymer grouting material;the compressive strength decreases with temperature increases under the same density,but the compressive strength is not significantly affected by temperature when the density is less than 0.4 g/cm3;the volume change of the samples accords with the law of thermal expansion and contraction when temperature changes,and the increase of the volume is obvious when it is under high temperature.The achievements will provide an important basis to the application of the polymer grouting material.

FRET-based polymer materials for detection of cellular microenvironments

Effective detection of cellular microenvironments and understanding of physiological activities in living cells remain a considerable challenge.In recent years,fluore scence(or Forster)resonance energy trans fe r(FRET)technology has emerged as a valuable method for real-time imaging of intracellular environment with high sensitivity,specificity and spatial resolution.Particularly,polymer-based imaging systems show enhanced stability,improved biodistribution,increased dye payloads,and amplified signal/noise ratio compared with small molecular sensors.This review summarizes the recent progress in FRET-based polymeric systems for probing the physiological environments in cells.