高功率射频微波用聚四氟乙烯及其复合材料关键技术

随着电子领域朝着高速传输、高连接密度的方向发展,对5G设备中广泛使用的覆铜板提出了低介电常数、低介电损耗、高导热率、高可靠性等技术要求。聚四氟乙烯(PTFE)覆铜板以其优异的介电性能和化学稳定性被广泛应用于高频微波电路领域,但现有PTFE覆铜板的制备在单体纯化、树脂聚合、填料改性、复合材料以及制品加工全链条中存在的问题限制了其实际应用。本文总结了近年来PTFE覆铜板的发展历程以及高频PTFE覆铜板面临的理论及技术难点,分别从高黏结性PTFE的分子设计及序列分布控制、高纯PTFE的全流程杂质含量可控及绿色产业化技术、新型填料制备及表面处理新技术、多相多组分PTFE复合材料的组成与界面设计、覆铜板的加工流变性与结构均匀性控制等方面提出了提升PTFE覆铜板性能的方法,以期能发展从树脂结构、填料改性、复合材料到成型加工的系统基础理论,从而制备高性能PTFE覆铜板。

Preparation of Poly-α-Olefin Microcapsule Particles Coated with Polyurethane as a Drag Reducer Based on Interface Polymerization

The molecular behavior of polyurethane(PU)coating materials during the surface adsorption of poly-α-olefin as a drag reducing polymer was explored by a molecular dynamics simulation.Three different PU capsule wall materials were synthesized using two reaction monomers,and a poly-α-olefin/PU drag reducer microcapsule was prepared based on interface polymerization.The structure,morphology,thermal stability,compressive strength,and drag reduction performance of the microcapsules were characterized and compared.The results showed that a non-bonding interaction induced the adsorption of the PU coating material,poly-α-olefin and PU then fused at the interface,and the PU coating material was embedded into the inner grooves of poly-α-olefin in the form of a local mosaic,thereby forming a stable core–shell structure.The morphological characterization indicated that PU and poly-α-olefin could form microcapsule structures.The thermal decomposition temperature of the microcapsule was dependent on the type of capsule wall material.The microcapsule structure had a slight effect on poly-α-olefin drag reduction.The system enabled poly-α-olefin to exist in powdered particles through microcapsulation,and had a good dispersion effect that facilitated storage and transport processes.The method effectively inhibited the accumulation and bonding of poly-α-olefin at room temperature.

Synthesis and Performance of an Associative Anti-shear Drag Reducer Based on Hydrogen Bond Association of Dodecyl Methacrylate

Using K2S2O8-Na2SO3 as the redox initiation system,a hydrogen-bond-association-based dodecyl methacrylate system associative anti-shear drag reducer was synthesised by standard emulsion polymerisation.The reaction process was simple and gentle as well as safe and stable.Molecular design was carried out using molecular dynamics simulation methods.The results of infrared spectroscopy,thermogravimetric analysis,differential scanning calorimetry,gel chromatography,and laser light scattering showed that the reaction polymerisation was relatively complete,the product was uniform,the molecular weight distribution was controllable,and the synthesised polymer had good flexibility.The donor lauryl methacrylate-styrene-methacrylic acid(LMA-St-MAA)and acceptor lauryl methacrylate-styrene-dimethylaminoethyl methacrylate(LMA-St-DMA)polymers had an associative intermolecular interaction force,which increased the molecular cluster size of the associative system complex.The complex had good shear resistance,and the test results of the tube pump shear test showed that the synthesised associative oil-soluble polymer drag reduction system exhibited better drag reduction rate performance than poly-α-olefins over repeated cycles.The research results provide a reference plan for minimising the number of station-to-station inputs,thereby ensuring the stability of oil pipelines and reducing transportation costs.