纳米材料 英文介绍

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DIFFERENCES BET WEEN TRADITIONAL COMPOSITES AND NANOCOMPOSITES
Traditional composites : – Micro-scaled fillers – Interface of fillers close to the bulk polymer • Nanocomposites: – Nano-scaled fillers – Ultra-large interfacial area per volume – Distances between the polymer and filler components are extremely short -Comparable dimensions of polymer coils(40nm in diameter) and nanoparticles molecular interaction between the polymer and the nanoparticles unusual material properties of nanocomposites.
Nanocomposites are not necessarily superior to conventional composites
Characteristics of Nanocomposites
Mechanical Properties -- Improvements in stiffness for all polymers --Reductions in strength and fracture toughness (except some elastomeric polymers) Dimensional Stability --Lower CTE, higher Tg & heat distortion temperature Flame Retardant Properties -- Lower heat release rate & lower mass loss rate Gas/Moisture Barrier Characteristics --Lower permeability and diffusivity
Definition of Nanocomposites
Composites with nanometerscale reinforcements Polymer nanocomposites (PNC) are polymers (thermoplastic , thermosetting or elastic) that have been reinforced with small quantities(less than 5% by weight) of nanosized particles having high aspect ratios (L/h>300)
Advantages & benefits of Nanocomposites
• Mechanical-related properties
– High specific stiffness and strength – Enhanced toughness
– Enhanced fatigue an creep resistance
– Better elevated temperature behaviour
• Chemical-related properties – Enhanced corrosion and degradation resistance
APPLICATIONS OF NANOCOMPOSITES
• Automobiles: --Air intake cover, fuel tank and other under the hood components due to the improved mechanical and thermal stability
Outline
Definition of Nanocomposites Characteristics of Nanocomposites Differences between Traditional composites and Nanocomposites Advantages of nanocomposites Applications of nanocomposites
• Enhancement of elastomeric properties:人造橡胶图片 -- for oil resistant HNBR（氢化丁腈橡胶） by the inclusion of Zinc（锌） di-methacrylate
• Thermal insulating coatings: --a layer of nanoporous(纳米多孔) silica（硅） on PI （聚酰亚胺）thin film coated by a 70nm thick Al films
– Better damage tolerance • Physical-related properties
Leabharlann Baidu– Controlled thermal expansion and conductivity
– Directional electrical and magnetic properties
• Flammability reduction: --layered silicates in PP and PS
Summary
With the rapid development of society and economy , nanocomposites will be regarded as an important and valuable direction for material research , we believe it will has a clear future.