STUDI KINETIKA DAN KARAKTERISASI HASIL SINTESIS POLIESTER DARI SHELLAC DAN ANHIDRIDA FTALAT
| Main Authors: | , LESTARI HETALESI SAPUTRI, , Prof. Ir. Rochmadi, S.U., Ph.D. |
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| Format: | Thesis NonPeerReviewed |
| Terbitan: |
[Yogyakarta] : Universitas Gadjah Mada
, 2014
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| Subjects: | |
| Online Access: |
https://repository.ugm.ac.id/128564/ http://etd.ugm.ac.id/index.php?mod=penelitian_detail&sub=PenelitianDetail&act=view&typ=html&buku_id=68917 |
Daftar Isi:
- This research aimed to modify shellac with phthalic anhydride, in order to improve properties of coating material. Although shellac is often used as a matrix, but pure shellac is brittle. The addition of phthalic anhydride is expected to increase the hardness, so that it is not easily broken. This research studies polyesterification kinetics for shellac-phthalic anhydride and the characteristics of the product. The Polyesterification kinetics study proposes two models by assuming that the reaction is in ideal system. In Model I, the reactivity of OH groups are considered equal, whereas in model II, the reactivity of the OH groups are considered different. The characterization of polyester products is carried out by the analysis of FTIR, XRD and hardness test of material. Shellac modification was started from purification by hydrolysis process. Hydrolysis was done by dissolving seedlac into NaOH solution and acidification with HCl. Polyesterification was conducted by reacting hydrolyzed shellac with phthalic anhydride. Both of these materials were reacted in a three necked flask under vacuum condition. The reaction was conducted in temperature range of 130-170°C and samples were taken every 30 minutes for a total of 5 hours, to determine the COOH concentration by titration. The effect of mole ratio was investigated at a constant temperature 150°C from range 0.6 to 2.4 (mol / mol). The result shows the influence of the addition of phthalic anhydride in polyesterification. From the FTIR analysis, the presence of esters and carboxylic acid groups was found, whereas the hardness test showed that polyester with a ratio of COOH/OH 0.7 had a higher hardness than other polyesters. The hardness level for polyester with the ratio of 0.7 was also reinforced by the degree of crystallinity shown by XRD analysis. The investigation of reaction kinetics showed that both reaction models could describe the kinetics of polyesterification shellacphthalic anhydride, especially for temperatures below 150°C. The reaction rate constants were obtained as follows: Model I: k11 = 0.7 e (-2643.03/T) g/mgek.menit k12 = 3.0 e (-3110.57/T) g/mgek.menit k13 = 1.5 e (-2879.67/T) g/mgek.menit k21 = 0.4 e (-2061.75/T) g/mgek.menit k22 = 0.8 e (-2820.94/T) g/mgek.menit k23 = 2.7 e (-3141.52/T) g/mgek.menit Model II: k1 = 19.7 e (-3802.82/T) g/mgek.menit k2 = 29.4 e (-4062.30/T) g/mgek.menit