具有核壳结构特征的相包容粒子设计及其对POM树脂的增韧条件

Design of Phase-containing Particles with Core-shell Morphology and Their Toughening Condition on POM Resin

以POM/TPU/CaCO3复合体系为基础,采用界面诱导技术使TPU被诱导并包覆在CaCO3表面上,自动地形成以CaCO3为核,以TPU为壳的相包容粒子,并实现了对POM树脂的有效增韧,改性材料不仅制备方法简单,而且在性能上完全达到了目前POM/TPU合金的水准。首次证明了利用具有包覆层的无机刚性粒子对高分子基体进行增韧时,其脆-韧转变不仅和增韧粒子的粒间距有关,而且和粒子包覆层厚度有关。对POM树脂而言,只有体系的粒间距达到临界值Tc≤0．18μm,且包覆层厚度达到临界值Lc≥0．7μm时,材料才有可能发生脆-韧转变,此时材料的冲击强度可比POM基体树脂增大十数倍,而且拉伸强度可达30MPa左右。

For POM/TPU/CaCO3 composite system, the phase-containing particles with CaCO3 as the core and TPU as the shell were achieved automatically by means of inducing TPU to coat CaCO3, and the particles could increase the toughness of POM resin effectively. The processing procedure is very simple and the mechanical properties of the composite material are comparable with POM/TPU alloy.More importantly, it was firstly demonstrated that using rigid inorganic particles with elastic shell to toughen polymer matrix, the brittle-ductile transition rule depended not only on interparticle distance,but also on shell thickness of the toughening particles. For POM resin, the composite system could not arrive B-D transition until at a critical interparticle distance Tc（ Tc≤0.18μm） and at a critical shell thickness Lc（Lc≥0. 7≥μm）. Once meeting the critical condition, the notch impact strength of the material was ten times greater than that of POM resin, and the tensile strength could reach around 30 MPa.