The effect of copolymer composition, gas content, and temperature on the bubbles nucleation and growth of styrene–methyl methacrylate copolymer/n-pentane foaming process

Abstract

The foaming process involves three important steps: nucleation, bubble growth, and stability. In the present work, the foaming dynamics of styrene–methyl methacrylate (St-MMA) copolymer/ n-pentane batch foaming system was studied at nonpressurized condition using rapid temperature increasing method. Synthesized copolymers with different compositions were characterized by proton nuclear magnetic resonance analysis and rheological measurements. An in situ foaming observation apparatus was designed, and the foaming dynamics (nucleation and bubble growth behavior) was studied. Dissolved n-pentane contents in all synthesized copolymer compositions at saturation temperatures, near their glass transition temperatures, were determined. The effects of foaming temperature, copolymer composition, and n-pentane content on the foaming dynamics of St-MMA copolymer/ n-pentane system were investigated. The foaming results revealed that the nucleation rate was increased with the increasing foaming temperature, while two other aforementioned parameters were kept constant. The nucleation and bubble growth rate were decreased with increasing MMA units in copolymer composition and increased with dissolved n-pentane content increment in copolymer matrix.

Systematic copolymer screening for foaming experiments supported by computational methods

“…17–23 A different approach besides blending is the synthesis of new polymeric materials, which is often performed by bulk polymerization of one or more monomers 24,25 or other free radical processes like suspension polymerization. 26–29 As blowing agents for polymeric foams, pentane 30–35 or carbon dioxide 3,36 and as monomers amongst others, methyl methacrylate (MMA) 37–39 and styrene (Sty) 40–42 are frequently utilized in literature. Different approaches have been performed towards the study of the foamability in dependence on the monomer ratio.…”

“…Different approaches have been performed towards the study of the foamability in dependence on the monomer ratio. 33,34 Nevertheless, the monomer ratios are not the only factors which influence the foaming. Additionally, the endfunctionalization 43 of the polymer chain as well as the chain length of the synthesized macromolecules 44 play an important role.…”

Numerical study of bubble nucleation and growth of N2 in low density polyethylene

“…The polymer foams have been used recently due to their greater characteristics, compared to solid polymers. [1][2][3][4] In foaming of polymers blown with blowing agents, numerous parameters such as saturation pressure and the thermodynamic instability could control the final bubble density, size, and growth rate. 4,5 Thermodynamic instability, may be provided through a rapid pressure release.…”

Effect of gelatin on the solubility and diffusivity of normal pentane in the poly (vinyl alcohol)/Gelatin blends

“…In thermodynamic study, some important parameters like the solubility and diffusivity of different gases in polymers and operation conditions like temperature and pressure must be investigated. [10][11][12][13] Between different systems for calculating the solubility and diffusivity, using the Magnetic Suspension Balance system is common method, which consists of a calculating chamber, and a balance located outside the chamber. [14][15][16] From the thermodynamic point of view, there is no study in literature about measuring solubility and diffusivity of normal pentane in poly (vinyl alcohol)/Gelatin.…”

“…25 In some studies about the polymer foaming processes, the measurements of the solubility and diffusivity of the gases as blowing agents in the polymer were performed prior to the foaming process. [26][27][28] The reason for this is to investigate the effect of gas solubility on its foaming properties. By increasing the gas solubility and diffusivity in polymer, the final cellular structure of produced foam was more homogeneously, due to the accessibility of more gas during the foaming process.…”