Waterborne polyurethane coatings based on bioresources and modified with cellulose nanocrystals

M.E.V. HORMAIZTEGUI; M.I. ARANGUREN; V.L. MUCCI

Los Cocos

Simposio; SAP 2017- XII Simposio Argentino de Polímeros; 2017

Laboratorio de Materiales Poliméricos (LaMaP) del Instituto de Investigación y Desarrollo en Ingeniería y Procesos y Química Aplicada (IPQA)

Waterborne polyurethanes (WBPUs) derived from vegetable oil have been developed in order to reduce the emissions of volatile organic compounds (VOCs) and increased the use of bio resources. [1] In order to introduce an ionic center in the molecular structure of the polymer, dimethylolpropionic acid (DMPA) is commonly used. In this work, two WBPUs were synthetized with a bio-based carboxylic acid (tartaric acid, that can be obtained from grapes) in order to replace the DMPA. On the other hand, cellulose nanocrystals (CNC) have been used as bio-reinforcement in many polyurethanes (also increasing the use of bio resources) and to improve for instance the mechanical properties of the matrix. [2]Bio-based WBPUs were synthesized from castor oil (CO) and tartaric acid (TA). Polycaprolactone diol (PCL) was used to contribute 15% to the OH groups in the formulation. The isocyanate used was isophorone diisocyanate (IPDI) and the amine was triethyl amine (TEA). The reaction was carried out in two steps; the first one was the reaction between the CO and the IPDI, or the CO and PCL and the isocyanate (2.5h) and the second reaction stage consists of the addition of the TA (2h). The amine was introduced into the reactor and finally water was added under vigorous stirring to obtain the nanoparticle dispersion.CNC were obtained through the acid hydrolysis of microcrystalline cellulose using sulfuric acid.[3] Suspension of CNC in water and dispersions of WBPU were mixed by mechanical stirring and then the suspensions were used in order to coat aluminum specimens by dip coating technique. The properties of these coatings will be tested through the techniques of contact angle, nano-indentation and scratching.REFERENCES[1]T. F. Garrison and M. R. Kessler, ?Plant Oil-Based Polyurethanes,? in Bio-based Plant Oil Polymers and Composites, Elsevier Inc., 2016, (2016) pp. 37?54.[2]V. Hormaiztegui, V. L. Mucci, A. Santamaria-Echart, M. A. Corcuera, A. Eceiza, and M. I. Aranguren, 44207, (2016) pp. 1?12.[3]J. M. Buffa, M. A. Grela, M. I. Aranguren, and V. Mucci, Carbohydr. Polym., 136, (2016) pp. 744?749.