Test Method for the Solubility Model of Physical Blowing Agent of Self-Expanding Polymer

Heyang Jia,Meimei Hao,Yanhui Zhong,Yang Li,Bei Zhang,Xiaolong Li,Isabella Torcicollo

doi:10.1155/2021/5566754

Abstract

This paper aims to present a solubility model of physical blowing agent (PBA) for a kind of commonly used self-expanding polymer on engineering. The self-expanding polymer contains Component A (isocyanate) and Component B (polyhydric alcohol, PBA, water, and catalyst). Component B grout of the polymer, which contains PBA, was heated to measure its temperature and volume variations. Based on the principle of mass conservation and Clapeyron equation, the solubility curve of PBA with respect to temperature was calculated. The solubility curve was then applied to simulate the foaming process. A two-component polymer grout foaming experiment was then carried out to verify the applicability of the measured solubility curve. The simulated changes of temperature and density with respect to time of polymer grout were analyzed and compared with experimental results. The error of both sets of curves is within 5%, which shows a good agreement among them and proves the feasibility of the solubility model. This study provides a relatively complete test and verification process for the solubility model of PBA, which lays a theoretical foundation for both the polymer grouting diffusion mechanism and engineering application.

Highlights

Grouting is an important method for antiseepage and reinforcement of engineering rock mass
Where Mi is the molecular weight and rCO2,D is the initial mass fraction of carbon dioxide. It can be seen from equation (6) that the density equation is closely related to rBG and rBL. is further proved the significance of obtaining an accurate physical blowing agent (PBA) solubility model for solving the polymer expansion process
An accurate solubility model of PBA is the prerequisite for studying the diffusion mechanism of self-expanding polymer grout. e main work and conclusion are summarized as follows: (1) is paper provides a fast and effective way to accurately obtain the PBA solubility model and its verification process of polymer, which is more complete than the previous researches

Summary

Introduction

Grouting is an important method for antiseepage and reinforcement of engineering rock mass. Numerical simulation on the chemical reaction process of polymer grout is an important way to study its expansion and diffusion mechanism. 2. Chemistry Reaction Mechanism e self-expanding polymer material is mainly constituted of isocyanate, polyhydric alcohol, blowing agent, water, and catalyst. Water is the common chemical blowing agent of polymer, which reacts with isocyanate to produce carbon dioxide and promote grout polymerization as well. With the progress of chemical reaction, a large amount of heat energy was produced, which causes continuous temperature increase of grout system. It can be seen from equation (6) that the density equation is closely related to rBG and rBL. is further proved the significance of obtaining an accurate PBA solubility model for solving the polymer expansion process

Test Method

Test Process

Summary and Conclusions

B: Physical blowing agent