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Bio-Based Rigid Polyurethane Foams for Cryogenic Insulation

Journal of Renewable Materials 2024年第3期12卷 585-602页

作者： Laima Vevere Beatrise Sture Vladimir Yakushin Mikelis Kirpluks ugis cabulis Latvian State Institute of Wood Chemistry RigaLV-1006Latvia

Cryogenic insulation material rigid polyurethane(PU)foams were developed using bio-based and recycled *** obtained from tall oil fatty acids produced as a side stream of wood biomass pulping and recycled polyethylene terephthalate were used to develop rigid PU foam *** 4th generation physical blowing agents with low global warming potential and low ozone depletion potential were used to develop rigid PU foam cryogenic insulation with excellent mechanical and thermal *** rigid PU foams had a thermal conductivity coefficient as low as 0.0171 W/m·K and an apparent density of 37-40 kg/m^(3).The developed rigid PU foams had anisotropic compression strength properties,which were higher parallel to the foaming ***,the compression strength was also influenced by the type of applied bio-based *** bio-based polyols with higher OH group functionality delivered higher crosslinking density of polymer matrix;thus,the mechanical properties were also *** mechanical strength of the foams increased when materials were tested at liquid nitrogen temperature due to the stiffening of the polymer *** thermal properties of the developed materials were determined using differential scanning calorimetry,dynamic mechanical analysis,and thermogravimetric analysis ***,the developed rigid PU foams had good adhesion to the aluminium substrate before and after applying cyroshock and an excellent safety coefficient of *** PU foams developed using Solstice LBA delivered adhesion strength of~0.5 MPa and may be considered for application as cryogenic insulation in the aerospace industry.

关键词： Cryogenic insulation polyurethanes tall oil 4th generation physical blowing agents

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Highly Functional Polyol Synthesis from Epoxidized Tall Oil Fatty Acids

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Journal of Renewable Materials 2018年第7期6卷 764-771页

作者： Edgars Vanags Mikelis Kirpluks ugis cabulis Zuzana Walterova Latvian State Institute of Wood Chemistry Dzerbenes 27LV-1006RigaLatvia

In this work, free tall oil fatty acids were epoxidized with in-situ generated peroxyacetic acid. Reaction kineticsof epoxidation was investigated by oxirane content and iodine value titrimetric determination, as well as FTIRspectra analysis. A highly functional biobased polyol was synthesized by functionalizing epoxidized tall oilfatty acids with triethanolamine using Montmorillonite K10 as a catalyst. The obtained polyol was analyzed byFTIR and MALDI-TOF MS. The most common chemical and physical characteristics of obtained polyol weredetermined.

关键词： Epoxidation biobased polyol ion-exchange resin catalyst montmorillonite K10 tall oil fatty acids

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Dielectric Permittivity of Rigid Rapeseed Oil Polyol Polyurethane Biofoams and Petrochemical Foams at Low Frequencies

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Journal of Renewable Materials 2020年第9期8卷 1151-1170页

作者： Ilze Beverte Vairis Shtrauss Aldis Kalpinsh Uldis Lomanovskis ugis cabulis Irina Sevastyanova Sergejs Gaidukovs Institute for Mechanics of Materials University of LatviaRigaLV-1006Latvia Latvian State Institute of Wood Chemistry RigaLV-1006Latvia Faculty of Materials Science and Applied Chemistry Institute of Polymer MaterialsInstitute of Applied ChemistryRiga Technical UniversityRigaLV-048Latvia

Early investigations of dielectric permittivity of rigid polyurethane foams at low frequencies were made on petrochemical-origin foams,mainly by means of parallel plate *** the present investigation biopolyol was synthesized from Latvia-grown rapeseeds’oil by the transesterification method with triethanolamine,in an environmentally friendly process,without emission of harmful substances,at temperatures 175℃±5℃.Rigid,closed-cell rapeseed oil polyol polyurethane biofoams and petrochemical foams were made ensuring content of the renewable rapeseed oil polyol in ready foams 27 wt.%–29 wt.%.Dielectric permittivity of the polyurethane foams and the underlying monolithic petrochemical-origin polyurethane and biopolyurethane was measured with a non-destructive dielectric spectrometer equipped with a capacitive sensor of one-side access type at 16 discrete frequencies distributed geometrically over the band 10 Hz,…,330 *** value of the gaseous phase in the closed-cells was estimated to beεg≈1.001 that corresponds to the values,characteristic for the most of *** permittivity of petrochemical polyurethane foams and the mentioned biofoams was compared with permittivity of polyurethane foams from industrial producers Sika JSC and General Plastics Manufacturing *** foams of the developed formulation exhibit competitive,low dielectric permittivity,not exceeding that of the foams from industrial producers:petrochemical foams up to 550 kg/m^(3) and the mentioned biofoams,comprising the renewable rapeseed oil polyol,up to densities 230–250 kg/m^(3).Considering petrochemical-origin polyurethane foams as a heterogeneous media“Polymer—gaseous phase”,the applicability of the rule of mixture and Maxwell–Garnett equation to model mathematically the dependence of effective dielectric permittivity on the volume fraction of phases was showed.

关键词： Polyurethane foams rapeseed oil polyol biofoams dielectric permittivity capacitive sensor one-side access low frequencies

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