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α‑トルキシル酸誘導体を用いた 官能性バイオベース
ポリマーの合成

Author(s)渡辺, 尚登CitationIssue Date

2017‑03

TypeThesis or Dissertation

Text version

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http://hdl.handle.net/10119/14203

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Supervisor:金子, 修士

達雄, マテリアルサイエンス研究科

Japan Advanced Institute of Science and Technology

Syntheses of functional bio-based polymers using α-truxillic acid derivatives

Kaneko lab.
1530060
Naoto Watanabe
1. Introduction
Plastics are indispensable to our lives. However, fossil fuel as its raw material is known as the cause of globalwarming. Using a bio-based raw material will realize a low-carbon society in the future. Generic bio-based
polymers such as polylactic acid have low heat resistance because it has Aliphatic backbone. Therefore, I
focused on 4-hydroxycinnamic acid (4HCA) as a raw material. It is a rigid structure with photoreactive double
bonds and aromatic rings. And it is a metabolic intermediate of lignin biosynthesis and can be artificiallysynthesized by reacting tyrosine with tyrosine ammonia-lyase (TAL). Our laboratory succeeded in synthesizing
highly heat-resistant polyester using 4HCA. The existence of double bond in the polymer induces
photodimerization and cis-trans isomerization, and demonstrated the possibility of application to functional
materials such as optical and mechanical materials and shape memory materials.
By irradiating 4HCA with ultraviolet light, 4,4'-dihydroxy-α-truxillic acid (4HTA) can be easily synthesized.
4HTA has two hydroxy groups and two carboxy groups, and if one functional group is used for syntheses, theother functional group remains in the side chain. Due to the presence of functional groups in the side chains,
solubility of polymers and polymer reactions can be improved, and so 4HTA is very valuable as a bio-basedmaterial. In this study, I synthesize two functional bio-based polymers by using 4HTA as a raw material.
Furthermore, measurement of various physical properties of the synthesized polymers and polymer reaction
give side chain functional group effect.

2. Experimental Section
2-1. Bio-based polycarbonate
Melt polymerization with diphenyl carbonate was adopted as a method for synthesizing polycarbonate.
However, since the melting point of 4HTA is higher than the decomposition temperature, melt polymerization
can’t be carried out. Therefore, a novel functional bio-based polycarbonate 4 was synthesized using 4,4’dihydroxy-α-truxillic acid methyl ester (4HTA methyl ester) in which 4HTA was methyl esterified.
2-2. Bio-based polyamides
In our laboratory, we synthesized a diamine / dicarboxylic acid compound using 4-aminocinnamic acid
(4ACA) as a raw material and bio-based polyamide was synthesized using them as monomers. Novelfunctional bio-based polyamide 15 using 4,4’-diamino-α-truxillic acid methyl ester (4ATA methyl ester) and4HTA was synthesized. Syntheses of polyamides 16, 17 using α-truxillic acid (TA) or 3,3’-dihydroxy-α-truxillicacid (3HTA) was also carried out in the same method.
2-3. O-Acetylation of 15
O-acetylation of 15 was carried out using acetic anhydride, pyridine and NMP.
2-4. Preparation of carbon fiber reinforced plastics (CFRP)-1-CFRPs was prepared using 15 and 19 obtained by O-acetylation of 15.

3. Results and Discussion
3-1. Bio-based polycarbonate
Thermal properties
The glass transition temperature was about 30 ℃ lower than conventional polycarbonate. This is thought tobe due to a decrease in the intermolecular force because side chains are bulky as compared with side chainsof conventional polycarbonate.
Solubility test
Compared to conventional polycarbonate, 4 has high solubility in polar solvents such as ethyl acetate,methanol, dimethyl sulfoxide. In addition, it did not have solubility in nonpolar solvents such as hexane andtoluene. From this, it is considered that the polarity of the side chain methyl ester improves the solubility inthese polar solvents.
Mechanical properties
4 fiber was prepared by heating to the glass transition temperature. Using this fiber, a tensile test was carriedout. Strength, Young's modulus and elongation at break were inferior to conventional polycarbonate. As
mentioned above, the side chain functional group is bulky and the intermolecular force is considered to belower than that of conventional polycarbonate.
3-2. Bio-based polyamides
Thermal properties
15, 16 and 17 showed very high decomposition temperatures. This is considered to be a rigid structure inwhich aromatic rings, amide bonds, cyclobutane rings are continuous and the stacking of aromatic rings is one
factor. In addition, the glass transition point of 15 and 17 exceeded the decomposition temperature. From theseresults, it is conceivable that the hydroxyl group on the side chains has an effect of reducing the distance
between polymer chains by non-covalent bonding, thereby improving intermolecular force and promoting
partial physically cross-linking.
Solubility test
15, 16, 17 were tested for solubility using various organic solvents and concentrated sulfuric acid. Initially, I
thought that the polarity of the side chain hydroxyl group would improve the solubility in organic solvents.
However, 15, 17 showed lower solubility in organic solvent than 16. In addition, the p-hydroxy group showed
lower solubility than the m-hydroxy group. As described above, this results is considered to be due to reductionof the distance between polymer chains by side chain hydroxy groups and partial physically cross-linking.
Furthermore, these effects were found to be higher for p-hydroxy groups than for m-hydroxy groups.
Mechanical properties
Cast film was cut into rectangular slices and mechanical strength was measured. Comparing 15, 16 and 17
both strength and Young’s modulus increased in the order of 16 < 17 < 15. As mentioned above, hydroxyl
groups bring polymer chains close to each other, improves the intermolecular force, and its effects increases
at the p-position.

-2-Optical properties
For measurements of transmittance, cast films prepared by dissolving in DMF was used. All three polymers
were highly transparent, equivalent to polycarbonate and Polymethyl methacrylate (PMMA), which are said tobe transparent plastics. This transparency is due to the fact that the conjugated system derived from aromaticrings and vinylene structures is interrupted by cyclobutane rings.
3-3. Polyamide 4
NMR spectra
From the NMR spectrum, it was found that 15 was O-acetylated. 19 was obtained as a gel-like solid.
Thermal properties
As results of O-acetylation of hydroxy groups, the heat resistance was lowered. It is considered that the side
chain became bulky due to the modification of hydroxy groups, and the distance between the polymer chains
was opened. Therefore, the intermolecular force decreased.
Solubility test
Solubility tests of 19 in various organic solvents and concentrated sulfuric acid were conducted. It was only
slightly soluble in dimethylsulfoxide and concentrated sulfuric acid. Before the modification of hydroxy groups,
it showed solubility in the amide type solvent, but after the modification it showed insolubility. This indicatesthat hydroxy groups have higher affinity with amide type solvents as compared with other solvents.
3-4. CFRP
Mechanical properties
Compared to 15, CFRP using 15 has greatly improved strength and young's modulus. When CFRP was madewith 19 O-acetylated with hydroxy groups, both strength and Young’s modulus were lower than CFRP using
15. It is considered that this is because side chain hydroxy groups interact more strongly with the surface
structure of the carbon fibers.

4. Conclusion
Novel functional bio-based polycarbonate 4 was synthesized using 4HTA methyl ester. Due to the bulkinessof side chain methyl esters, heat resistance and mechanical strength were inferior to conventional
polycarbonate. However, due to the polarity of the methyl ester, the solubility in the polar solvent was increased
as compared with the conventional polycarbonate. Three new functional bio-based polyamides 15, 16, 17 weresynthesized using 4HTA and 3HTA, TA and 4ATA methyl ester. By heat resistance measurement, it was foundthat side chain hydroxyl groups reduce the distance between polymer chains, giving intermolecular force
improvement and partial physical crosslinking. Also, by the solubility test, it was found that p-hydroxy groups
had this effect higher than m-hydroxy groups. As a result of NMR measurement, it was found that O-acetylationof 15 was successful. Mechanical strength measurements of CFRPs using 15 and 19 showed hydroxy groups
is more likely to interact with the surface structure of carbon fibers.

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