Research And Application Of Experimental Apparatus On Microcellular Foaming

Micro-pore foaming plastics are the polymer foam with the pore of 1μm to 100μm.Compared with the traditional non-foaming plastics,it has the following advantages:(1) more lighter;(2) better sound-proof and adiabatic characteristic;(3) better mechanical property;and so on.Thus,it attracts much attention of researchers from worldwide.In this study,a micro-pore foaming device based on high pressure autoclave was developed in order to explore the morphology of foaming pore fully and enhance the mechanical property of foaming plastics.It includes the cavity with the typical shape and dimension,pressure relief system with adjustable flow rate,data acquisition system for cavity system and enhanced cooling system.Accordingly,it has the following advantages,(1)mechanical property tests can be done for the typical foaming plastics;(2)forming parameters,such as foaming temperature,foaming pressure,foaming time and pressure relief velocity,can be modified sensitively;(3)the relationship between the forming parameters and the morphology of foaming pore , macroscopic mechanical property can be studied quantitatively,and the optimal forming parameters can be obtained;(4)the pressure relief velocity of cavity can be controlled,so the cooling and shaping of foaming sample can be controlled.Firstly,the mechanical structure of this micro-pore foaming device was developed using the 3-D modeling software.Finite element analysis,ANSYS Workbench,was used to analyze the deformation size,stress and strain of the high pressure autoclave,and to check the strength and rigidity of the bearing structure,which can assure the leak tightness,safetyandoperating life.Meanwhile,Moldflow software was utilized to model and analyze the cooling system of this device,so the cooling result can be predicted and the optimal designing scheme can be obtained.Then,the micro-pore foaming device was fabricated and established.Using the micro-pore foaming device,polystyrene(PS) micro-pore foaming plastics was formed to verify the working feasibility of this device.The effects of foaming temperature,saturation pressure and pressure relief velocity on the morphology of foaming pore was studied.The micro-pore foaming plastics sample with typical size was formed using this device and the mechanical test was carried out.Results showed that the micro-pore foaming plastics can be successfully formed using this device.The foaming pore,with the size smaller than 10 um,is uniformly disturbed and has the large density,which means that the morphology of foaming pore is improved greatly.The samples had very smooth superficial coat,which can improve the mechanical property of foaming plastics.They can be tested directly to determine the macroscopic mechanical properties,such as the extending property,etc.This study provides a platform to investigate the properties of micro-pore foaming plastics deeply.Furthermore,it provides a useful reference for the extend of commercial product of micro-pore foaming plastics.