Dimensionally Stable Water-Blown Polyurethane Foam Extended With Bio-Based Propylene Glycol and Modified With Paper Waste Sludge

Abstract

Paper waste sludge (PWS) is the main and the greatest by-product in paper production process, and its elimination as well as destruction is a primary environmental problem. This research explores the feasibility of such wastes to be used in polyurethane foam composites. It is well known that using water as a sole blowing agent has major drawbacks such as long demould time, shrinkage, high diffusion rate of carbon dioxide and etc.; therefore, the bio-based propylene glycol (RPG) is used in order to solve such problems. The addition of 20 parts by weight (pbw) of RPG eliminates the primary shrinkage of the foam composites when PWS is used in the amount varying from 5% to 20%, and improves the dimensional stability at 70 oC and 90% relative humidity conditions. The addition of titanate coupling agent modified PWS particles increases the compressive strength of the final composites from ̴ 26% to ̴ 53%, from ̴ 17% to ̴ 31% and from ̴ 3% to ̴ 23% for, respectively, 10 pbw, 15 pbw and 20 pbw RPG extended foam composites.

Properties of Rigid Polyurethane Foam Filled with Sawdust from Primary Wood Processing

“…However, no significant changes in foam thickness were observed (<0.5%). By Kairytė et al [ 65 ], the increased shrinkage of the foam means that its structure is not rigid enough to provide equilibrium with the pressure difference between the cellular structure and the surrounding environment. The presence of larger closed cells and thinner cell walls, which were observed for foams with a higher proportion of WF, promotes intense diffusion of CO 2 , which increases the shrinkage of the final product [ 66 ].…”

Improved dimensional stability of water‐blown polyurethane foam with aluminum hydroxide and magnesium hydroxide

“…The dimensional stability [9,10] of the foam was measured over the course of 7 days by placing the foam in a convection oven at 23 and 70 C. To measure the dimensional changes, the foam volume was measured on Days 2 and 7 at each temperature using an electronic densimeter (DME-220, Shinko Denshi). The initial foam specimen size was 30 × 30 × 25 mm 3 , and the core densities of the foam specimens were obtained.…”

“…[4,5] PU foam is used in the construction, transportation, and medical fields, and is also used in studies of biopolyol-based PU foams [6,7] and natural filler-added PU composites. [8,9] However, water-blown PU foam, especially lowdensity foam, is dimensionally unstable due to the change of pressure within the cells of PU foam. This is because CO 2 gas in the cells can easily move out through the cell walls, while replacement with air to fill the cells is a slow process.…”