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聚合物纳米复合材料

聚合物纳米复合材料. 卢红斌 博士、副教授 复旦大学高分子科学系 跃进楼 210 室 电话： 55664589 （办） Email:hongbinl@fudan.edu.cn. 2004 年 10 月 13 日. 研究思路. (1) Structural adjustment. Molecular Structure Adjustment. Topological Structure Adjustment. C T E. Flexible chain. High. Semi-Stiff chain. No polymer network

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聚合物纳米复合材料

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  1. 聚合物纳米复合材料 卢红斌 博士、副教授 复旦大学高分子科学系 跃进楼210室 电话：55664589（办） Email:hongbinl@fudan.edu.cn 2004年10月13日

  2. 研究思路 (1) Structural adjustment Molecular Structure Adjustment Topological Structure Adjustment C T E Flexible chain High Semi-Stiff chain No polymer network No particle network Polymer network + local particle network Interpenetrating polymer and particle networks Contribution to CTE and mechanical properties Stiff chain Low Low High (2) Low CTE Nanoparticles Montmorillonite Attapulgite MWCNT Polyoxometalate

  3. 固体颗粒表面改性 (1)Montmorillonite (MMT) Ion Exchange Na+ Na+ Na+ Na+ Na+ Na+ (2) Attapulgite (ATT) -OH Activation, Covalently Bonding -OH -OH (3) Multiwall Carbon Nanotubes (MWCNT) Oxidation, Functionalization (4) Polyoxometalate (POM) Coordination/Anion Exchange

  4. 蒙脱土/环氧纳米复合材料-受限松弛 （1） 相同条件下的纯树脂和复合材料的DSC 曲线：10 oC/min 相同过冷度下的不同材料的焓松弛比较：Tg-20 oC 退火372小时

  5. 蒙脱土/环氧纳米复合材料-受限松弛 （2） Hongbin Lu, Steven Nutt, Macromolecules, 2003, 36(11):4010-4016 Anastasiadis, S.H., Phys. Rev. Lett. 2000, 84(5):915-918 (Greece);

  6. 受限松弛的唯象解释 (1) Segmental Relaxation Non-Debye relaxation process Nonlinearity: Tf=Tg Heat capacity or enthalpy, Cp or Sc b Non-equilibrium glass Nonexponentiality: Equilibrium liquid Dh* Sc’, Tf’ x Temperature, T （TNM Model）

  7. 受限松弛的唯象解释 (2) Adam-Gibbs model: Overview • Using cooperatively rearranging concept to elucidate the change in configurational entropy during segmental motions. Results High surface area + Good interface adhesion Lower configurational entropy Slower segmental motion Good stability and mechanical properties Hongbin Lu, Steven Nutt, Macromol. Chem. Phys. 2003, 204: 1832-1841

  8. 玻璃化转变的热力学－动力学相关性 (C. A. Angell et al, Nature, 2001, 410, 663-667)

  9. 玻璃化转变的构象熵模拟 Configurational Entropy Model: (Gomez Ribelles, J. L. et al. Macromolecules, 1995, 28, 5867; 1995, 28, 5878.)

  10. 构象熵模拟结果 热力学和动力学脆性之间：反相关

  11. 热力学和动力学之间的联系 我们的建议： 然而 m  16 ? Hongbin Lu, Steven Nutt, Macromolecules, submitted

  12. 棒状硅酸盐/环氧纳米复合材料

  13. 棒状硅酸盐/环氧纳米复合材料-实验结果 Hongbin Lu, Steven Nutt et al., Adv. Mater., submitted

  14. 多壁碳纳米管/环氧纳米复合材料 • Discovered by Iijima in 1991 • Outstanding properties: • Tensile modulus SWNT: ~ 1.25 TPa ; 56 times higher than steel wire 1.7 times higher than silicon carbide nanonods • Electrical conductivity 104 S/cm; higher than amorphous metal Calcium-Aluminum (103 S/cm) • Thermal conductivity MWNT: > 3000 W/m-K; higher than graphite (2000 W/m-K) • Thermal expansion coefficient SWNT: ~ -1.5 ppm K-1

  15. 多壁碳纳米管/环氧纳米复合材料 • Two critical issues • Uniform dispersion • Good interfacial adhesion • Current strategy (Covalent bonding and Noncovalent bonding) • Covalent Functionalization • Sonication Acylchloride: Fluorination:

  16. 多壁碳纳米管/环氧纳米复合材料 Simple Functionalization Method with Commercial Potential Advantages: (1) rather mild reaction conditions (reflux at 80 oC) (2) shorter reaction time (~ 1 h) (3) higher functionalization efficiency (~ 4 wt %)

  17. 多壁碳纳米管/环氧纳米复合材料 • Only characteristic adsorptions of amine groups, no isocyanate groups • 3.7  0.9 % weight loss of organic molecules

  18. 多壁碳纳米管/环氧纳米复合材料 MWNTs MWNTs-epoxy Composites

  19. 多壁碳纳米管/环氧纳米复合材料 MWNT-Epon 862-DDM Nanocomposites (DMA)

  20. 多壁碳纳米管/环氧纳米复合材料 Two important factors: • Exclusive volume effect below Tg • Confined segmental motions above Tg

  21. 多壁碳纳米管/环氧纳米复合材料 Dynamics simulation for SWNT-PS: CTE increases, whether in rubber state or in glass state Neutron reflectivity experiments: CTE decreases in the rubber state, due to the boundary confinement of polymer films (Wei, Nano Letters, 2002, 2, 647) (Pochan, Macromolecules, 2001, 34, 3041)

  22. 即将开展的工作 零膨胀有机高分子材料 有机热电材料 受限链段动力学 聚合物纳米复合材料流变学

  23. 零膨胀材料 New Concepts and New Materials DSPN Components: Low CTE Inorganic Nanoparticles Polymer molecules 1. Mesoporous nanoparticles: ZrW2O8 (CTE =~ -8.5×10-6 K-1) HfW2O8 (CTE =~ -5.3×10-6 K-1) 2. Nanobuilding blocks: Mesoporous particle (Inorganic clusters with low CTE) (SiW10O36(RPO)2)4-) Zr10O6(OH)4(OPr)18(AAA)6

  24. 有机热电材料 应用前景、研究现状 • 加电制冷－－绿色冰箱，红外传感器制冷，电脑芯片制冷等; • 温差发电－－太阳能热电转换电池，热机式原子能电池，人 造卫星电源等。 Brian C. Sales, Science, 2002, 295, 1248

  25. 有机热电材料 基本原理、性能参数 Seebeck 效应：温差产生电流 Peltier 效应： 电场导致冷却 热电性能表征 热电优值 ZT = S2sT/k S－ Seebeck 系数；s－ 电导率；k－ 热导率。 家用冰箱的能量转换效率（卡诺系数）：30％ 大型中央空调设备的卡诺系数： 90％ 现有热电材料(ZT ~ 1.0)的卡诺系数： < 10％

  26. 有机热电材料 最好的热电材料－PbSeTe/PbTe QDSL ZT = 2.0 at 300 K, k = 3.3 W/m.K, DT = 42.7 K T. C. Harman, P. J. Taylor, M. P. Walsh, B. E. LaForge Science, 2002, 297, 2229

  27. 有机热电材料 有机热电材料的优势 • 有机导电高分子：Seebeck 系数 ～1800，电导率：～ 104 热导率：< 1.0 加工设备简单、易于规模化生产、成本低廉 使用温度 < 400 oC • 无机半导体： Seebeck 系数 ～ 250，电导率：～ 800 热导率： > 2.0 温度范围：0～ 1300 K，多需在洁净和真空下制备

  28. (4)流变学 聚合物纳米复合材料熔体流变学  纳米颗粒增强机理 力学增强 拓扑结构 逾渗阈值 界面作用  高分子链运动的温度依赖性 链运动与链段运动温度依赖性的相关性； 固体网络结构（颗粒维数）对温度依赖性的影响等。

  29. 感谢您的宝贵建议！

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