Morphology And Property Of Reactive Microgel/Nylon Blends

Reactive microgel is an intramolecular crosslinked macromolecule in the size of1nm-1000 nm with different reactive groups such as carboxyl, hydroxyl, sulfonyl and amino groups on the surface or inside. This microgel can be crosslinked with other monomers or macromolecule under appropriate conditions to get the heterogeneous network polymer.Nylon 6 is an important class of crystalline engineering thermoplastics which has been applied widely. However, the low notched impact strength of nylon 6 limits its application, so it is important to modify nylon 6. The most commonly method is blending the elastomer or plastic with nylon 6. The addition of the elastomer or plastic into nylon 6is an effective method to improve the impact strength, but the effect is not very obvious due to poor compatibility. Blending reactive microgel with nylon 6 can improve the compatibility of the blends. It has important theoretical significance and application prospects in improving the rheological and mechanical properties. As a combination of organic nano-particles and thermoplastic elastomer, reactive microgel is expected to provide a new idea for modifying nylon 6.In this paper, the reaetive mierogel was synthesized by the emulsion polymerization technique, chareacterized by differential scanning calorimetry(DSC), dynamic light scattering(DLS),infrared spectroscopy(IR) and transmission electron microscopy(TEM).The isothermal crystallization and non-isothermal crystallization behavior of nylon 6 with varying content of reactive microgel was investigated by using DSC. The crystallization behavior of the polymer was analyzed through the crystallization kinetics,the results are as follows:(1)The isothermal crystallization kinetics of reactive microgel/nylon 6 blends was analyzed by the Avrami, Arrhenius and Hoffman theories. The crystallization rate constant Z and the Avrami exponent n reflects that the nucleation process and growth mechanism of the nylon 6 changes with the adding the reactive microgel; The crystallization activation energy(?E) of the reactive microgel/nylon 6 blends is higher than that of the pure nylon 6,the addition of reactive microgel can decrease the crystallization rate of nylon 6. However,the values of ?E are not linearly increasing with the increase of reactive microgel, when the concentration of reactive microgel reaches 30%, the values of ?E gets to a maximum.(2)Multi melting behaviors of nylon 6 and its blends were investigated by DSC.Results showed that melting curves of the pure nylon 6 and the content of the reactive microgel at 20% and 30% of reactive microgel /nylon 6 blends appeared three peaks within 186~194?,while the content of the reactive microgel at 40% and appeared double peaks. the apparennt equilibrium melting temperature of the reactive microge/nylon6 is higher than the apparent equilibrium melting temperature of neat PA6,the addition of the reactive microgel increases the lamellar thickness of nylon 6 crystal,indicating the presence of the reactive microgel contributes to increase the degree of perfection of crystal structure of nylon 6.(3)The non-isothermal crystallization kinetics of reactive microgel/nylon 6 blends was investigated by the Jeziorny theory, the Ozawa theory and the Mo theory. Jeziorny method can handle the initial stages of the crystallization process of nylon 6, Ozawa method is not suitable for handling the crystallization process of nylon 6, while the Mo equation is more suitable to analyze the non-isothermal crystallization data.The results show that the nucleation process and growth mechanism of the nylon 6 changes with the adding the reactive microgel, the addition of reactive microgel can decrease the crystallization rate of nylon 6. The crystallization activation energy was evaluated by Kissinger equation. The values of ?E of reactive microgel/nylon 6 blends are higher than that of neat nylon 6.When the concentration of reactive microgel is 30%, the values of ?E gets to the maximum.