Study On Rheology And Crystallization Property Of Multi-component Polymer Blends And Polymer Solution

The miscibility and crystallization of solution casting biodegradable poly(3-hydroxybuty-rate)/poly(ethylene succinate) (PHB/PES) blends was investigated by differential scanning calorimetry(DSC), rheology, and optical microscopy. The blends showed two glass transition temperatures and a depression of melting temperature of PHB with compositions in phase diagram, which indicated that the blend was partially miscible. The morphology observation supported this result. The experiment approved that the PHB composition can affect the G'very prominently, which indicate PHB is the definitive part for properties of mechanics. It was found that the PHB and PES can crystallize simultaneouslyor upon stepwise depending on the crystallization temperatures and compositions. The spherulite growth rate of PHB increased with increasing of PES content. The infuence of compositions on the spherulitic growth rate for the partially miscible polymer blends was discussed. According to the temperature sweep in the rheometer, we can draw a conclusion that the two phase transformation temperatures of 50/50 composition are 85℃and 135℃.The rheology properties of hydrophobically modified PEG with alkyl group of 16 carbon aqueous solution is investigated with Rheometer RheoWin MARS错误!未找到引用源。. The results of dynamic frequency sweep indicate that dynamic complex viscosity increase with the increasing of the concentration. When reaching critical association concentration(CAC), the complex viscosity abrupt change .At different temperature ,the complex viscosity is different for the polymer of same concentration, and as the temperature increases, CAC decrease for the effect of interaction force between hydrophilic group and hydrophobic group which make the particle aggregation easy. In this text, the solution is manifested as shear thinning when CAC>150g/l and T>70℃,.this is a mutation of rhelogical and mechanical properties which is attributed to mutual force of molecular chain.The results of dynamic frequency sweep indicate that dynamic complex viscosity increase with the increasing of the concentration. When reaching critical association concentration(CAC), the complex viscosity abrupt change .At different temperature ,the complex viscosity is different for the polymer of same concentration, and as the temperature increases, CAC decrease for the effect of interaction force between hydrophilic group and hydrophobic group which make the particle aggregation easy. In this text, the solution is manifested as shear thinning when CAC>150g/l and T>70℃,.this is a mutation of rhelogical and mechanical properties which is attributed to mutual force of molecular chain.The effect of molecular weight to PEO Poly(ethylene oxide) crystallization for is discussed by DSC. Kinetics of isothermal is analyzed by Avrami equations. The result show that: With the increase of molecular weight crystallization rate parameter Z decreases. Also the higher the temperature, the smaller the crystallization rate parameter is, and the longer the half crystallization times are. When n<4,the sample grow into spherulite by heterogeneous nucleation and three dimensional growth. In addition, n is not an integer for the reason that molecular chains can not only diffuse and adjust freely through macromolecular crystallization from the molten state, but also entangle. There are various crystalline mechanism for one process of isothermal crystallization .So, n only have average and statistical meaning. Meanwhile, the date of non-isothermal crystallization is investigated by the new equation researched of Mo et al.