Research Of Molding With Thermal Melting Of Polymer Gradient Structure

Based on the dissipative structure to transformthe traditional polymer hot molten polymer forming mold.Energy was continuously,provided to the dynamic template of mold by controling the device,and keep temperature constant,at the same time,control the static template temperature below the dynamic template certain valueand keep constant,which implement the mold cavity thermodynamic state stability control,and the negtive entropy flow was successfully introduced in the mold cavity,and constuct the open system of energy exchange with the outside system.Using the specific forming mould,and the traditional injection molding equipment and technology,combined with the polymer blending system of the crystalline/crystalline,crystalline/amorphous,and amorphous/amorphous different combination,and investigating the self-organization phenomena in the mold cavity during the injection molding.When the crystalline copolymer high densitypolyethylene(HDPE)/ polyoxyethylene(PEO)were at injection molding stage,through regulating thermodynamic state of the forming mold cavity,and introducing a large enough negative entropy flow,which triggered system dissipation and spontaneously derived material movement.The HDPE/PEO blend melt turned a chaotic uniform form into an orderly gradient form,and selectivelyprepared with self-organization the traditional uniform structure and gradient phaseseparation structure.The composition of sample section was characterized by POM,ATM-FTIR,Microscope-ATR-FTIR and Nanoindentation.It was found thatturning the cavity thermodynamic state into equilibrium self-organized the most disordered uniform structure;and HDPE concentrates at the low-temperature-side which the energy flows out while PEO at the high-temperature-side which the energy flows in,as the negative entropy flowof the system is increasing by introducing a negative entropy flow into the cavity with non-equilibrium state.The composition of the resulted films distributes gradually along with energy movement direction and presents the tendency of increase with the negative entropy flow and the molding time.In addition,non-equilibrium state is the major factor that affects the formation of gradient structure.Whencrystalline/amorphouspolypropylene(PP)/ethylene-octene-copolymer(POE)w ere at injection molding stage,through regulating thermodynamic state of the forming mold cavity,which can selectively prepare with self-organization the traditional uniform structure and gradient phase separation structure.POM and nano indentation Showed that PP concentrates at the low-temperature-side which the energy flows out while POE at the high-temperature-side which the energy flows in,and in the direction of negative entropy flow,PP/POE blending system formed gradient phase separation structure.In PP/POE sample of gradient phase separation structure,modulus and hardness presented the same gradient distribution rule along with the change of the section composition.When the amorphous copolymer polystyrene(PS)/ethylene-octene-copolymer(POE)were at injection molding stage,through regulating thermodynamic state of the forming mold cavity,which can selectively prepare with self-organization the traditional uniform structure and gradient phase separation structure.FTIR results showed that when negative entropy flow was zero in PS/POE blending system,formed the same uniform stucture.PS concentrates at the low-temperature-side which the energy flows out while POE at the high-temperature-side which the energy flows in,and in the direction of negative entropy flow,PS/POE blending system formed gradient phase separation structure.At non-equilibrium thermodynamics state injection molding,self organization mechanism of formed orderly gradient structure is due to negative entropy flow which was caused by heat flow and material flow in the system.The differences of polymer thermal motion ability leaded to form concentration gradient in the direction of heat flow and cool solidification.The formation of a concentration gradient only depended on the negative entropy flow and molding time,without crystallization of polymer.The results showed that any polymer combinations of different thermal motion ability all can use the traditional polymer injection molding equipment selectively prepared the traditional sea-island uniform structure and the gradient structure of different morphologies without the affect of crystalline.This result showed that the prospect industrial preparing gradient polymer materials will vigorously promote the industrial production and application of gradient polymer materials.