Synthesis and curing of alkyd enamels based on ricinoleic acid
A combination of an alkyd resin with a melamine-formaldehyde resin gives a cured enamel film with the flexibility of the alkyd constituent and the high chemical resistance and hardness of the melamine resin at the same time. The melamine resin is a minor constituent and plays the role of a crossl...
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| Format: | Article |
| Language: | English |
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Association of Chemical Engineers of Serbia
2010-01-01
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| Series: | Hemijska Industrija |
| Subjects: | |
| Online Access: | http://www.doiserbia.nb.rs/img/doi/0367-598X/2010/0367-598X1000056J.pdf |
| _version_ | 1819044351611764736 |
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| author | Jovičić Mirjana C. Radičević Radmila Ž. Simendić Vesna B. |
| author_facet | Jovičić Mirjana C. Radičević Radmila Ž. Simendić Vesna B. |
| author_sort | Jovičić Mirjana C. |
| collection | DOAJ |
| description | A combination of an alkyd resin with a melamine-formaldehyde resin gives a cured enamel film with the flexibility of the alkyd constituent and the high chemical resistance and hardness of the melamine resin at the same time. The melamine resin is a minor constituent and plays the role of a crosslinking agent. In this paper, alkyd resins of high hydroxyl numbers based on trimethylolpropane, ricinoleic acid and phthalic anhydride were synthesized. Two alkyds having 30 and 40 wt% of ricinoleic acid were formulated by calculation on alkyd constant. Alkyds were characterized by FTIR and by the determination of acid and hydroxyl numbers. Then synthesized alkyds were made into baking enamels by mixing with melamine-formaldehyde resins (weight ratio of 70:30 based on dried mass). Two types of commercial melamine resins were used: threeisobutoxymethyl melamine-formaldehyde resin (TIMMF) and hexamethoxymethyl melamine resin (HMMMF). Prepared alkyd/melamine resin mixtures were cured in a differential scanning calorimeter (DSC) under non-isothermal mode. Apparent degree of curing as a function of temperature was calculated from the curing enthalpies. Kinetic parameters of curing were calculated using Freeman-Carroll method. TIMMF resin is more reactive with synthesized alkyds than HMMMF resin what was expected. Alkyd resin with 30 wt% of ricinoleic acid is slightly more reactive than alkyd with 40 wt% of ricinoleic acid, probably because it has the high contents of free hydroxyl and acid groups. The gel content, Tg, thermal stability, hardness, elasticity and impact resistance of coated films cured at 150°C for 60 min were measured. Cured films show good thermal stability since the onset of films thermal degradation determined by thermogravimetric analysis (TGA) is observed at the temperatures from 281 to 329°C. Films based on alkyd 30 are more thermal stable than those from alkyd 40, with the same melamine resin. The type of alkyd resin has no significant effect on the gel content and the hardness of film. Hardness of cured film increases with increasing of Tg. The values of the films elasticity are satisfied for all prepared samples and are independent on the type of alkyd or melamine resin. The impact resistances of coated films are very high. |
| first_indexed | 2024-12-21T10:11:18Z |
| format | Article |
| id | doaj.art-37bcb1a364b04250a6f869f79dc510af |
| institution | Directory Open Access Journal |
| issn | 0367-598X |
| language | English |
| last_indexed | 2024-12-21T10:11:18Z |
| publishDate | 2010-01-01 |
| publisher | Association of Chemical Engineers of Serbia |
| record_format | Article |
| series | Hemijska Industrija |
| spelling | doaj.art-37bcb1a364b04250a6f869f79dc510af2022-12-21T19:07:42ZengAssociation of Chemical Engineers of SerbiaHemijska Industrija0367-598X2010-01-0164651952710.2298/HEMIND100824056JSynthesis and curing of alkyd enamels based on ricinoleic acidJovičić Mirjana C.Radičević Radmila Ž.Simendić Vesna B.A combination of an alkyd resin with a melamine-formaldehyde resin gives a cured enamel film with the flexibility of the alkyd constituent and the high chemical resistance and hardness of the melamine resin at the same time. The melamine resin is a minor constituent and plays the role of a crosslinking agent. In this paper, alkyd resins of high hydroxyl numbers based on trimethylolpropane, ricinoleic acid and phthalic anhydride were synthesized. Two alkyds having 30 and 40 wt% of ricinoleic acid were formulated by calculation on alkyd constant. Alkyds were characterized by FTIR and by the determination of acid and hydroxyl numbers. Then synthesized alkyds were made into baking enamels by mixing with melamine-formaldehyde resins (weight ratio of 70:30 based on dried mass). Two types of commercial melamine resins were used: threeisobutoxymethyl melamine-formaldehyde resin (TIMMF) and hexamethoxymethyl melamine resin (HMMMF). Prepared alkyd/melamine resin mixtures were cured in a differential scanning calorimeter (DSC) under non-isothermal mode. Apparent degree of curing as a function of temperature was calculated from the curing enthalpies. Kinetic parameters of curing were calculated using Freeman-Carroll method. TIMMF resin is more reactive with synthesized alkyds than HMMMF resin what was expected. Alkyd resin with 30 wt% of ricinoleic acid is slightly more reactive than alkyd with 40 wt% of ricinoleic acid, probably because it has the high contents of free hydroxyl and acid groups. The gel content, Tg, thermal stability, hardness, elasticity and impact resistance of coated films cured at 150°C for 60 min were measured. Cured films show good thermal stability since the onset of films thermal degradation determined by thermogravimetric analysis (TGA) is observed at the temperatures from 281 to 329°C. Films based on alkyd 30 are more thermal stable than those from alkyd 40, with the same melamine resin. The type of alkyd resin has no significant effect on the gel content and the hardness of film. Hardness of cured film increases with increasing of Tg. The values of the films elasticity are satisfied for all prepared samples and are independent on the type of alkyd or melamine resin. The impact resistances of coated films are very high.http://www.doiserbia.nb.rs/img/doi/0367-598X/2010/0367-598X1000056J.pdfalkyd/melamine enamelssynthesiscuringDSCTGAcoating film properties |
| spellingShingle | Jovičić Mirjana C. Radičević Radmila Ž. Simendić Vesna B. Synthesis and curing of alkyd enamels based on ricinoleic acid Hemijska Industrija alkyd/melamine enamels synthesis curing DSC TGA coating film properties |
| title | Synthesis and curing of alkyd enamels based on ricinoleic acid |
| title_full | Synthesis and curing of alkyd enamels based on ricinoleic acid |
| title_fullStr | Synthesis and curing of alkyd enamels based on ricinoleic acid |
| title_full_unstemmed | Synthesis and curing of alkyd enamels based on ricinoleic acid |
| title_short | Synthesis and curing of alkyd enamels based on ricinoleic acid |
| title_sort | synthesis and curing of alkyd enamels based on ricinoleic acid |
| topic | alkyd/melamine enamels synthesis curing DSC TGA coating film properties |
| url | http://www.doiserbia.nb.rs/img/doi/0367-598X/2010/0367-598X1000056J.pdf |
| work_keys_str_mv | AT jovicicmirjanac synthesisandcuringofalkydenamelsbasedonricinoleicacid AT radicevicradmilaz synthesisandcuringofalkydenamelsbasedonricinoleicacid AT simendicvesnab synthesisandcuringofalkydenamelsbasedonricinoleicacid |