纤维/气流双向耦合作用下的熔喷微纳米纤维结构演变机制

Melt blowing (MB) is a widely used one-step process to produce micro-nano fibers by drawing a molten polymer in the air jet with high speed and temperature. However, fibers fabricated by MB technique usually have some shortcomings, such as low fiber strength and large coefficient of variation for fineness. These shortcomings are closely related to the evolution history of fiber structure in melt-blowing. The aim of this project is to investigate the evolvement mechanism of the micro-nano fiber structure under the two-way coupling interaction between fiber and air jet. In detail, three parts are involved: (1) Based on the Maxwell heat conduction theory for the suspended nanoparticle two-phase fluid and volume of fluid (VOF) model, the effect of the fiber on the air jet will be analyzed and the coupling model will be established by considering the simultaneous heat and mass transfer from air jet to the fiber; (2) The theories including fiber/air jet heat and mass transferring model, crystallization kinetics, stress-optic law will be coupled into the MB kinetic model to predict the evolution of both the macroscopic and microcosmic structures for MB fibers; (3) New methods for controlling fiber macroscopic and microcosmic structures will be explored. For instance, supersonic die, reheating, temperature adjusting collection or electrospinning/melt-blowing coupled method will be tried. The project will provide the theoretical basis for the controllable manufacturing and improving mechanical properties of MB fibers and contribute to the micro-nano fiber manufacturing industry in China.

熔喷技术是利用高温高速气流拉伸聚合物熔体直接制备微纳米纤维材料的一种重要方法，但存在纤维强度低、细度不匀大等缺点，而这些问题与熔喷过程中纤维结构演变历程密切相关。本项目拟研究纤维/气流双向耦合传质传热作用下的纤维结构演变机制，即(1)基于Maxwell纳米粒子悬浮两相流导热理论和流体体积函数（VOF）模型，研究纤维对气流场分布的影响机制，并考虑气流场对纤维的热质同时传递，建立纤维/气流双向耦合传质传热模型；(2)将纤维/气流双向耦合传热传质模型与动力学模型结合，并引入结晶动力学模型和应力-光学定律，预测熔喷纤维宏观和微观结构参数的动态演变过程及其影响因素；(3)探索调控熔喷纤维宏观和微观结构的新方法，研究超音速口模、二次加热、静电辅助牵伸或调温接收等方法对纤维结构成形的影响。本项目的实施可为实现熔喷微纳米纤维的可控制备及性能提高提供理论基础，为提升我国微纳米纤维制造业水平作出贡献。

熔喷技术是利用高温高速气流拉伸聚合物熔体直接制备超细纤维材料的一种重要方法，但存在纤维强度低、细度不匀大且难以纳米化等缺点，而这些问题与熔喷过程中纤维结构演变历程密切相关。本项目对纤维/气流双向耦合传质传热作用下的纤维结构演变机制进行研究，建立了熔喷纤维/气流双向耦合传质传热模型，明晰了纤维与气流的双向耦合作用机制，探明了纤维/气流双向耦合传质传热作用下的熔喷纤维宏观结构演变规律；建立了熔喷纤维微观结构演变模型，实现了对熔喷工艺纺程上纤维结晶度及取向度的动态演变过程的预测；提出并探索了静电感应辅助熔喷工艺和气流自耦合熔喷模头两种调控熔喷纤维结构的方法，为规模化可控制备纳米纤维、提高熔喷非织造材料性能提供了新方法。基于本项目研究内容，项目组共在国内外期刊发表论文16篇（其中SCI收录13篇、EI收录2篇），申请国家发明专利5项（其中授权1项），培养博士生5名，硕士生4名。