Research For Rare Earth Additives Improve Pp High Pressure CO₂ Microfoaming

This article uses low-cost,environmentally friendly high-pressure CO₂ as a blowing agent,by adding appropriate amounts of rare earth additives and foaming dispersing aids,in the work station to provide autoclave-style foaming.By changing the temperature,pressure,holding time,type and content of additives,combined with relevant literature to explore the impact of various processing conditions on the foaming behavior and mechanism.The experiment used a polypropylene material with the brand name T-3410,and the different types and contents of rare earth additives were added through regranulation to obtain the polypropylene raw material particles required for the test.The experimental results show that the addition of additives can not change the foaming range of polypropylene,but it has a significant effect on the foaming rate of the foamed product,the shape of the cells,theβ-crystal content of the raw material and foamed particles.The characterization methods used in the experiment mainly include DSC scanning,SEM,and XRD.The results show that the foaming window of this brand of polypropylene is 133°C-135°C.When the other conditions are constant,the higher the temperature,the greater the foaming magnification.When other conditions are constant,the higher the foaming pressure,the greater the foaming magnification.When other conditions are constant,the holding time has little effect on the foaming magnification,but it has a great influence on the cell morphology.This article innovatively uses Wei Lina’s self-produced rare-earth additive as a foaming aid and beta crystal nucleating agent to provide strength support for the EPP product molding stage through the high-temperature beta crystals.A polypropylene foaming bead with a maximum foaming ratio of 17 times was obtained in the experiment,and a polypropylene foamed bead having a multi-cell size characteristic and a good thermal insulation property was obtained.The influence mechanism of temperature,pressure,holding time,addition amount and type of nucleating agent on the foaming magnification,cell morphology,etc.was explored and proposed,which has guiding significance for the subsequent industrial production.