Thermogravimetric investigation of sol–gel microspheres doped with aqueous glycerol

Sustainable Chemical Processes

Rosaria Ciriminna¹  Giuseppe Pantaleo¹  Rosa La Mattina¹  Mario Pagliaro¹ 

[1] Istituto per lo Studio dei Materiali Nanostrutturati, CNR, via U. La Malfa 153, Palermo, 90146, PA, Italy

关键词: Solid curing agents;    One-component foam;    Sol–gel microencapsulation;    Curing;    PU foams;   

Others  :  1216788
DOI  :  10.1186/s40508-014-0026-x

 received in 2014-09-18, accepted in 2014-12-11,  发布年份 2014

【 摘 要 】

Background

Silica-based microspheres encapsulating aqueous glycerol are promising curing agents affording the formation of better one-component polyurethane foams, namely thermoset polymers cured by atmospheric moisture that are widely and increasingly utilized in the construction industry. The use of renewable, non toxic glycerol from biodiesel and oleochemicals industry to cure PU foams in place of traditionally employed oil-derived mono and diethylene glycols is both technically and environmentally beneficial. The higher amount of hydroxyl groups in glycerol compared to both mono- and diethylene glycol results in considerably lower percentage of free monomeric methylene diphenyl diisocyanate (MDI) and higher crosslinking density of the cured foam.

Results

We investigate by thermogravimetric analysis the nature and amount of the microencapsulated species in sol–gel silica and organosilica microspheres encapsulating aqueous glycerol. Along with a percentage of glycerol in weight up to 35%, the microspheres contain about 5 wt% water and 4 wt% entrapped surfactant.

Conclusions

The investigation shows the efficacy of the surfactant-assisted sol–gel microencapsulation aqueous glycerol in silica as well as in methyl-silica particles at least until 10% degree of methylation. The results are relevant to the practical development of functional materials that can be used to cure better and greener polyurethane foams largely employed as coatings, adhesives and sealants in many industrial sectors.

【 授权许可】

   
2014 Ciriminna et al.; licensee Springer.

【 图 表 】

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【 参考文献 】

• [1]Ciriminna R, Marques AC, Bordado JC, de Schrijver A, Pagliaro M, GreenCaps: Towards solid curing agents for sustainable polyurethane foams.Sustain Chem Processes 2014, 2:24.
• [2]Ciriminna R, Alterman A, Loddo V, De Schrijver A, Pagliaro M: Enhanced one-component spray polyurethane foams via sol–gel microspheres doped with aqueous glycerol. ACS Sustainable Chem Eng 2014, 2:506-511.
• [3]Tadros TF: Applied surfactants: principles and applications. Wiley-VCH, Weinheim; 2005.
• [4]Ashida K: Polyurethane and related foams: chemistry and technology. CRC Press, Boca Raton; 2007.
• [5]IAL Consultants: Global Overview of the Spray Polyurethane Foam (SPF) & One Component Foam (OCF). London: October 2014.
• [6]US Environmental Protection Agency, Methylene Diphenyl Diisocyanate (MDI) and Related Compounds Action Plan Summary, November 2013. Available at the URL: http://www.epa.gov/oppt/existingchemicals/pubs/actionplans/mdi.html.
• [7]Meckel-Jonas C: (Henkel), Polyurethane Laminating Adhesives and Food Safety: A Smart Alliance. TAPPI Flexible Packaging Symposium India, New Delhi; 2009.
• [8]Hu C, Wan Y, Li : Production and characterization of biopolyols and polyurethane foams from crude glycerol based liquefaction of soybean straw. Bioresour Technol 2012, 103:227-233.
• [9]Luo X, Hu S, Zhang X, Li Y: Thermochemical conversion of crude glycerol to biopolyols for the production of polyurethane foams. Bioresour Technol 2013, 139:323-329.
• [10]Ciriminna R, Della Pina C, Rossi M, Pagliaro M: Understanding the Glycerol Market. Eur J Lipid Sci Technol 2014, 116:1432-1439.
• [11]Gómez EF, Luo X, Li C, Michel FC Jr, Li Y: Biodegradability of crude glycerol-based polyurethane foams during composting, anaerobic digestion and soil incubation. Polym Degrad Stabil 2014, 102:195-203.
• [12]Handbook of industrial surfactants. Ash M, Ash I (Eds), 4th edition, Synapse Information Resources: 2005.
• [13]Barbé CJA, Finnie KS, Kong L: Particles having hydrophobic material therein WO2006133518A1.
• [14]See at the URL: http://www.merck-performance-materials.com/en/cosmetics/eusolex/eusolex_uv_pearls/eusolex_uv_pearls.html.
• [15]Rottman C, Grader GS, De Hazan Y, Avnir D: Sol-gel entrapment of ET (30) in ormosils. Interfacial polarity-fractality correlation. Langmuir 1996, 12:5505-5508.
• [16]Lobnik A, Wolfbeis OS: Polarity studies on ormosils using a solvatochromic fluorescent probe. Analyst 1998, 123:2247-2250.
• [17]Galgali G, Schlangen E, van der Zwaag S: Synthesis and characterization of silica microcapsules using a sustainable solvent system template. Mater Res Bull 2011, 46:2445-2449.