Elaboration and Characterization of Advanced Biobased Polyurethane Foams Presenting Anisotropic Behavior

Abstract

Biobased and open cell polyurethane (PU) foams are produced from a synthesized sorbitol‐based polyester polyol. Different formulations are developed with various blowing agent systems (chemical vs physical blowing). Synthetized foams are fully characterized and compared. The cell morphology is carefully investigated by tomography and scanning electron microscopy. The chemical nature of the primary compounds, foaming kinetics, density, thermal behavior, and conductivity are fully studied, with also the main transition materials temperatures. It is shown that blowing agents especially impact the foaming kinetics. In the case of chemically blowing foams, higher foaming rate and temperatures are obtained. The mechanical behavior is particularly analyzed using quasi‐static compression tests, according two main axes compared to the rise direction. A direct relationship is observed between the formulation, foam structure, foam morphology, and corresponding mechanical properties. Results clearly highlight unexpected properties of biobased PU foams with unveil anisotropic mechanical properties.

Biobased foams for thermal insulation: material selection, processing, modelling, and performance

“…Because these properties are so desirable, a vast amount of research has been dedicated to nding biobased replacements for the traditionally petroleum-based polyols. [16][17][18][19][20][21][22][50][51][52][53][54][55][56] The alternative polyols are commonly developed from different plant oils, of which the typical structure does not contain the functional groups (epoxy, amine, thiol, hydroxyl) necessary to react with the isocyanate. Most plant oils consist of a glycerol backbone and an oleic, a linoleic, and a linolenic acid chain.…”

“…These foams were generated by adjusting the biobased polyol content along with the ratio of PBA (CO 2 ) to CBA (water) used. 54 The fact that an anisotropic foam structure can be formed both with this method for PU and with freeze dried cellulose (see Section 2.2) exemplies how much of an impact processing conditions have on the outcome of producing foams.…”

“…Micro-CT scanning of experimental foams to create structural information inputs for a model is a potential means ll this gap. 116 Additionally, all models assessed here have neglected to account for the possibility of polymer blends or solid Table 1 Assumptions regarding structure and heat transfer mechanisms and predictions made by a variety of thermal conductivity models 42,43,47,48,106,113,116,122 2 Assumptions made in a variety of models corresponding to comparable observations in experimental biobased foams [13][14][15][16][17][18][19][20][21][22][23][24]26,27,[41][42][43]47,48,54,62,64,73,106,113,116,122,123 additives. Granted, it is not reasonable to consider every possible additive, but certainly it would be desirable to have a better understanding of how different polymer domains in a blend impact thermal conductivity depending on how those domains are arranged.…”

Evaluation of biological degradation of polyurethanes

“…Diversification of PU properties allowed to reach other numerous markets. In 2016, 18 million tons of PU were produced worldwide, representing 5.3% of global plastic production (Furtwengler et al, 2018a;PlasticsEurope, 2017). PU rank at the 6 th most produced synthetic polymers.…”

New Insight on the Study of the Kinetic of Biobased Polyurethanes Synthesis Based on Oleo-Chemistry

“…With more than 60%, foams are the largest part of this market, with segments including the furniture, bedding, insulation, building, or construction materials. Foams are elaborated through a complex formulation that is based on polyols, polyisocyanates, blowing agent, and several other additives [2,3]. Commercial foams are mainly formulated with fossil-based components.…”