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Preparation of Drying Oil Encapsulated Urea-Formaldehyde for Self-repairing Coating

K ing M ongkut’s U niversity of T echnology T honburi S chool of E nergy, E nvironment and M aterials. Preparation of Drying Oil Encapsulated Urea-Formaldehyde for Self-repairing Coating. By Nuenghatai Khong -in Napachat Tareelap Nandh Thavarungkul Choochat Nitipanyawong

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Preparation of Drying Oil Encapsulated Urea-Formaldehyde for Self-repairing Coating

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  1. King Mongkut’sUniversity of Technology Thonburi School of Energy, Environment and Materials Preparation of Drying Oil EncapsulatedUrea-Formaldehyde for Self-repairing Coating By NuenghataiKhong-in NapachatTareelap NandhThavarungkul ChoochatNitipanyawong NakornSrisukhumbowornchai

  2. Motivation O2 O2 O2 Microcapsule Paint matrix Urea-formaldehyde Drying oil Metal Previous research prepared microcapsules encapsulated commercial linseed oil [2] and tung oil [3] • Thermoset polymer • From film by reacted with oxygen in the air • Composed of unsaturated fatty acid : • conjugated bond and non-conjugated bond • Conjugated bond dried faster than non-conjugated bond [1] In Thailand the drying oil can be extracted fromParinariumanamenseHance seed which is called Mapok oil Self-repairing Coating used for corrosion prevention Shell Urea-formaldehyde Core Natural None of reports compared properties of linseed oil, tung oil and mapok oil [1] Onusa, 1994 [2] Samadzadehet al. (2011) and [3] Suryanarayanaet al. (2008)

  3. Objective To compare drying property of natural drying oil (linseed oil, tung oil and mapok oil) and select to prepare microcapsules encapsulated urea-formaldehyde for self-repairing coating

  4. Experimental Procedure Properties of dried film (Part 1) The cleaned steel (size 50 mm x 50 mm x1 mm) coated epoxy paint and cross cut deep to steel Oil Coated drying oil as linseed oil, tung oil and mapok oil on cross-cut area for 7 days epoxy paint Observed and selected drying to used repairing agent Non-crack film No Yes Cross-cut Microcapsule preparation (Part 2) The cleaned steel

  5. Microcapsule Preparation Before add formaldehyde 1-Octanol 1-2drop 5wt% sol HCl in DI water pH 3 Urea 5 g NH4Cl 0.5 g Resorcinol 0.5g Oil 30ml 5wt% aq. PVA 10 ml + DI water 260 ml • Varying • Ratio U:F 1:2 and1:4 • Agitation rate 250 and 500 rpm Filtration under vacuum, rinse with DI water and xylene Urea-formaldehyde net work 37 wt% aq. Formaldehyde Heat 55ºC for 4 hr. Oil After add formaldehyde and heat 55oC Core  Selected drying oil Shell  Urea-formaldehyde Suryanarayana, 2008

  6. d Experimental Procedure • Microcapsule preparation (Part 2) • Varying • Ratio of U:F 1:2 and 1:4 • Agitation rate 250 and 500 rpm Microcapsules put onoil absorbing sheet Dryingoil Oil content checking by compression with couple of glass slide Having oil No Oil absorbing sheet Yes Examine oil leaking observed every 2 week for 20 weeks Oil leak Yes Area of microcapsules (d = 1 cm) Leaked oil Leaking area (mm2) = Total area– Area of microcapsules No - Morphological Examinationby SEM - Particle size distribution Prepare self-repairing coating (Mixed microcapsule in epoxy paint and coated on surface steel) Corrosion test by Immersion in NaCl 3.5wt% for7 days

  7. Results and Discussion

  8. Appearance and Property of Dry Film Cross cut surface Solid film Oil

  9. Appearance and Property of Dry Film Clear film Unsmooth film Micro-crack Crack-free film

  10. Composition and Film Formation of Drying Oil Non-Conjugated Conjugated (dry fast) Selected linseed oil to prepare micro-capsules Film formation drying oil Tung oil and Mapokoil Oxygen attack on the conjugated Linseed oil Oxygen attack on non-conjugated Linseed oil Mapok oil Non-Crack Crack Form 2radicals Non-cracked film Cracked film Form 1radical [1] M. Samadzadeha, 2011 [2] Onusa, 1994

  11. Preparation microcapsule urea-formaldehyde encapsulated linseed oil

  12. Oil content and Oil Leak Testing Table showed oil after compression and leaked area of microcapsule / found oil in microcapsules Oil leaked Ratio urea: formaldehyde

  13. Mechanism Urea-formaldehyde Ratio UF 1:2 [1] Di-methylol urea Urea Formaldehyde UF Network Ratio UF 1:4 [1] Cross-link Formaldehyde Urea Treta-methylol urea UF Network Selected condition ratio of UF 1:4 - To observe morphology - Particle size distribution Hans R. Oskar N. and Graham S. [1]

  14. Morphology and Particle Size Distribution b) 500 rpm a) 250 rpm Size Agitation Morphology of microcapsule and size distribution of microcapsules condition UF ratio 1:4 difference agitation rate a) 250 rpm and b) 500 rpm

  15. Corrosion Test 500 µm Rust Rust Size Dispersion

  16. Conclusions • Linseed oil provided non-crack dried film while film from mapok and tung oil cracked because of lesser amount of conjugated fatty acid. • Linseed oil encapsulated urea-formaldehyde microcapsules prepared from U:F ratio of 1:4 could prevent oil leaking because of high cross-linked density UF shell. • Self-repairing coating prepared from linseed oil encapsulated urea-formaldehyde microcapsules could delay corrosion in comparison to epoxy paint without microcapsules.

  17. Acknowledgements • Assoc.Prof. Dr. PraneePhinyocheep. Faculty of Science, Mahidol University, Bangkok for useful discussion • The National Research Council of Thailand (NRCT) is acknowledged for financial support

  18. Thank you for your attention http://mehariqbal.wordpress.com/2011/01/18/you-worked-hard-but-not-hard-enough/

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