Yumuşak grup içeren poli(arileneterketon)ların (paek) sentezi
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Poli(arileneterketon), ısısal oksitlenme kararlılığı ve iyi mekanik özelliklerinden dolayı mükemmel bir mühendislik plastiğidir. Bu çalışmada aromatik dikarboksilli asitlerin yanma alifatik uzun zincirler içeren Pripol 1017 katılarak modifiye poli(eterketon)lar elde edilmiştir. Amacımız poli(eterketon)larm çözünürlüğünü arttırmak ve modifiye edilmiş poli(eterketon)un termal davranışlarım incelemektir. Elde edilen veriler, Pripol 1017'nin değişik moi oranlannın poli(eterketon)un yapısına girmesi halinde ı\ni viskozite değerinde değişme olmadığını, fakat Pripol 1017'nin yapıya girmesi ile çözünürlüğün artma eğiliminde olduğunu göstermiştir.
Since poly(aryleneetherketone) (PAEK) has shown promise as an excellent engineering plastic because of its good mechanical property and thermooxidative stability, the synthesis of aromatic poly(etherketones) has become of interest in recent years. A number of synthetic routes for producing poly(etherketones) have already been described in the literature. They can be prepared in two ways: 1. By a nucleophilic substitution reactions 2. By an electrophilic substitution reaction In nucleophilic substitution reaction, alkali metal phenoxides are reacted with activated aromatic halides in order to give high yields of the corresponding ethers. Among activating groups, sulfone, carbonyl and cyano groups are particularly useful for polymer preparation. As leaving groups, increasing reactivity order is F>Cl»Br O Na Na O II 0-- Several high molecular weight polymers were prepared in this method. Two factors essential for the formation of high molecular weight polymers, besides chemical reactivity, are: VI 1. Choise of a suitable solvent and 2. Exclusion of air and water. DMSO and sulfolane are the preferred solvent because of their ability to dissolve the alkali bisphenoxides as well as the growing polymer chains under anhydrous conditions. The presence of water causes hydrolysis of the activated aromatic halides and, to a small extent, chain scissions via the attack of sodium hydroxide on the polymer chains. The ease with which phenoxides are oxidized at elevated temperatures requires the exclusion of atmospheric oxygen. In the second method, polymerization has been carried out by Friedel- Crafts acylation. In this manner a number of Friedel-Crafts catalysts have been developed. HF/BF3 combination, strong acids such as trifluoromethanesulphonic acid are useful solvents as well as catalysts for electrophilic substitution. ci-c Lq- o <5-c, <0^D AICI, O >4-4 J n Ueda et al. first used phosphorus pentoxide/methanesulphonic acid (PPMA) in a weight ratio of 1:10 for the preparation of poly(etherketones) n In our work, we obtained the modified poly(aryleneeterketone) by inserting various amount of dimer acid Pripol 1017 to the main chain as a soft segment. VII Pripol dimer acids produced by the polymerization of unsaturated C18 fatty acids are viscous liquids. They exhibit marked physical differences from that of other commercially available dibasic acids such as adipic, azeiaic and sebasic acid. Pure dimer acid D is a Cjg aliphatic dibasic acid. Its structure is essentially that of a long-chain dicarboxylic acid with two alkyl side chains. It appears to contain at least one ethylenic bond. hJu^MU-oh The reaction conditions and properties of resulting modified poly(aryleneetherketone) were given in TABLE 1 The IR spectrum of poly(aryleneetherketone) (PEK6) shows the peaks of aliphatic C-H at 2800-3000 cm"1, the peak of aliphatic ketone about 1700 cm-1, the peak of aromatic ketone about 1650 cm-1, the peak of aromatic ring at 1600 cm"1, the peak of aromatic ether at 1230 cm"1 revealing structure (Figure 1) On the other, enhanced solubility character of poly(aryleneetherketone) (PEK6) afforded to have been a 1H-NMR spectrum (Figure 2) 1H-NMR spectra shows multi aromatic peaks about 7-8 ppm, multi aliphatic C-H peaks about 0,9-3 ppm. Introducing various amount of soft segment as Pripol 1017 to the poly(etherketone) polymer, big differences in r\ted values could not be observed. However PEK 5 and PEK 6 dissolves in THF and CHC13 as common organic solvents.
Since poly(aryleneetherketone) (PAEK) has shown promise as an excellent engineering plastic because of its good mechanical property and thermooxidative stability, the synthesis of aromatic poly(etherketones) has become of interest in recent years. A number of synthetic routes for producing poly(etherketones) have already been described in the literature. They can be prepared in two ways: 1. By a nucleophilic substitution reactions 2. By an electrophilic substitution reaction In nucleophilic substitution reaction, alkali metal phenoxides are reacted with activated aromatic halides in order to give high yields of the corresponding ethers. Among activating groups, sulfone, carbonyl and cyano groups are particularly useful for polymer preparation. As leaving groups, increasing reactivity order is F>Cl»Br O Na Na O II 0-- Several high molecular weight polymers were prepared in this method. Two factors essential for the formation of high molecular weight polymers, besides chemical reactivity, are: VI 1. Choise of a suitable solvent and 2. Exclusion of air and water. DMSO and sulfolane are the preferred solvent because of their ability to dissolve the alkali bisphenoxides as well as the growing polymer chains under anhydrous conditions. The presence of water causes hydrolysis of the activated aromatic halides and, to a small extent, chain scissions via the attack of sodium hydroxide on the polymer chains. The ease with which phenoxides are oxidized at elevated temperatures requires the exclusion of atmospheric oxygen. In the second method, polymerization has been carried out by Friedel- Crafts acylation. In this manner a number of Friedel-Crafts catalysts have been developed. HF/BF3 combination, strong acids such as trifluoromethanesulphonic acid are useful solvents as well as catalysts for electrophilic substitution. ci-c Lq- o <5-c, <0^D AICI, O >4-4 J n Ueda et al. first used phosphorus pentoxide/methanesulphonic acid (PPMA) in a weight ratio of 1:10 for the preparation of poly(etherketones) n In our work, we obtained the modified poly(aryleneeterketone) by inserting various amount of dimer acid Pripol 1017 to the main chain as a soft segment. VII Pripol dimer acids produced by the polymerization of unsaturated C18 fatty acids are viscous liquids. They exhibit marked physical differences from that of other commercially available dibasic acids such as adipic, azeiaic and sebasic acid. Pure dimer acid D is a Cjg aliphatic dibasic acid. Its structure is essentially that of a long-chain dicarboxylic acid with two alkyl side chains. It appears to contain at least one ethylenic bond. hJu^MU-oh The reaction conditions and properties of resulting modified poly(aryleneetherketone) were given in TABLE 1 The IR spectrum of poly(aryleneetherketone) (PEK6) shows the peaks of aliphatic C-H at 2800-3000 cm"1, the peak of aliphatic ketone about 1700 cm-1, the peak of aromatic ketone about 1650 cm-1, the peak of aromatic ring at 1600 cm"1, the peak of aromatic ether at 1230 cm"1 revealing structure (Figure 1) On the other, enhanced solubility character of poly(aryleneetherketone) (PEK6) afforded to have been a 1H-NMR spectrum (Figure 2) 1H-NMR spectra shows multi aromatic peaks about 7-8 ppm, multi aliphatic C-H peaks about 0,9-3 ppm. Introducing various amount of soft segment as Pripol 1017 to the poly(etherketone) polymer, big differences in r\ted values could not be observed. However PEK 5 and PEK 6 dissolves in THF and CHC13 as common organic solvents.
Açıklama
Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 1995
Konusu
Asitler, Oksitlenme, Sentez, Acids, Oxidation, Synthesis