Use of a Mixture of Polyols Based on Metasilicic Acid and Recycled PLA for Synthesis of Rigid Polyurethane Foams Susceptible to Biodegradation

Abstract

Two polyol raw materials were obtained in the conducted research, one based on metasilicic acid (MSA), the other based on poly(lactic acid) (PLA) waste. The obtained polyols were characterized in terms of their applicability for the production of rigid polyurethane foams (RPUFs). Their basic analytical properties (hydroxyl number, acid number, elemental analysis) and physicochemical properties (density, viscosity) were determined. The assumed chemical structure of the obtained new compounds was confirmed by performing FTIR and 1H NMR spectroscopic tests. Formulations for the synthesis of RPUFs were developed on the basis of the obtained research results. A mixture of polyols based on MSA and PLA in a weight ratio of 1:1 was used as the polyol component in the polyurethane formulation. The reference foam in these tests was a foam that was synthesized only on the basis of MSA-polyol. The obtained RPUFs were tested for basic functional properties (apparent density, compressive strength, water absorption, thermal conductivity coefficient etc.). Susceptibility to biodegradation in soil environment was also tested. It was found that the use of mixture of polyols based on MSA and PLA positively affected the properties of the obtained foam. The polyurethane foam based on this polyol mixture showed good thermal resistance and significantly reduced flammability in comparison with the foam based MSA-polyol. Moreover, it showed higher compressive strength, lower thermal conductivity and biodegradability in soil. The results of the conducted tests confirmed that the new foam was characterized by very good performance properties. In addition, this research provides information on new waste management opportunities and fits into the doctrine of sustainable resource management offered by the circular economy.

Synthesis of Mono Ethylene Glycol (MEG)-Based Polyurethane and Effect of Chain Extender on Its Associated Properties

“…These outcomes showed that the hard polymer increasingly accumulated to make the domains in the polyurethane copolymer with an increase in hardness [ 34 ]. The Figure evidently depicts the impact of the extender on the polymer [ 46 ]. The amine groups (–NH), attached with hydrogen bonding, stretched at 3309, 3323, 3323, and 3315 cm −1 , in Figure 1 B–E, respectively [ 35 , 47 ].…”

Evolution Law of Structural Form and Heat Transfer Performance of Thermal Insulation System

“…This gas has a much smaller thermal conductivity than air [ 25 , 26 ]. The size and distribution of these pores also play crucial roles in the material’s thermal insulation performance [ 27 ]. In general, RPUF exhibits the following basic characteristics [ 28 , 29 ]: Regularly arranged closed pores.…”

Synthesis of bio‐polyurethanes with isosorbide and propanediol based poly(lactic acid) diol

“…Using PLA-based polyol and metasilicic acid (MSA)based polyol to obtain rigid polyurethane foam had decreased the apparent density from 95.5 to 89 kg/m 3 , and improved the aging resistance. 19 It was reported 20 for PLA/Isosorbide dioctoate (SDO) blends that SDO lowered PLA's glass transition (T g ) and improved the elongation at break from 3.5% (neat PLA) to 11.2% (10 wt.% SDO). The incorporation of a bio-based PU consisting of castor oil (CO) and ISO into PLA 21 lead to a balanced strength and toughness of the resulting polymer.…”

“…Reports 17,18 attest that customized, that is, with a controlled ratio of flexible (polyol)/rigid (isocyanate) segments, poly(lactic acid) polyurethanes (PLAUs) are suitable for industrial uses such as adhesives and coatings. Using PLA‐based polyol and metasilicic acid (MSA)‐based polyol to obtain rigid polyurethane foam had decreased the apparent density from 95.5 to 89 kg/m 3 , and improved the aging resistance 19 . It was reported 20 for PLA/Isosorbide dioctoate (SDO) blends that SDO lowered PLA's glass transition ( T g ) and improved the elongation at break from 3.5% (neat PLA) to 11.2% (10 wt.% SDO).…”