Effect of alcohols-regulated crystallization on foaming process and cell morphology of polypropylene

Abstract

A novel approach was established to promote favorable PP foams at low temperatures by regulating the melt crystallization behavior. The crystallization behavior of PP on supercritical CO2 foaming was systematically studied in the presence of alcohol as co-blowing agent. The results of dissipative particle dynamics (DPD) simulations revealed that the diffusion coefficient of blowing agents in PP was enhanced with the increase of alcohol molecular weight. Alcohols had a significant effect on the melt and crystallization behavior of PP. The crystallization temperature was decreased from 88 ℃ to 82 ℃, and crystallinity declined from 17% to 9% by adding 1-decanol in 8 MPa CO2. The addition of co-blowing agents decelerated desorption rate of blowing agents. The lower limit of foaming temperature moved further down with the carbon chain growth of alcohol, e.g., the lower temperature decreased from 145 ℃ to 130 ℃ by adding 1-decanol.