Supplementary Information. Environmentally-Degradable, High-Performance Thermoplastics. from Multifunctional Phenolic Phytomonomers

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1 Supplementary Information Environmentally-Degradable, High-Performance Thermoplastics from Multifunctional Phenolic Phytomonomers Tatsuo Kaneko*, Hang Thi Tran, Dong Jian Shi, Mitsuru Akashi * *To whom correspondence should be addressed. kaneko@jaist.ac.jp (T.K.) 1. Materials and methods 2. Solubility of the copolymers 3. Semiempirical calculation for one of the most stable conformation of model compounds 4. Wide angle X-ray diffraction (WAXD) study 5. Stress-strain curves 6. Infrared spectroscopy change of the copolymer by UV-irradiation 7. UV absorption change of the copolymer in the liquid crystalline state by UV-irradiation 8. 1H NMR spectra of the supernatant solution of the degraded copolymer pellets 9. Degradation in soil 10. Weight change of the copolymer pellet UV-irradiated for various times

2 1. Materials and Methods 1-1 Materials p-coumaric acid {4-hydroxycinnamic acid, 4HCA; Tokyo Chemical Industry (TCI)} and caffeic acid (3,4-dihydroxycinnamic acid, DHCA; TCI) were used as monomers, and were used as received. The acetic anhydride (Wako Pure Chemical Industries, Ltd.) and sodium acetate (Wako Pure Chemical Industries, Ltd.) used for polymerization were used as received. The acetone (Wako Pure Chemical Industries, Ltd.) used as a washing solvent was used as received. Dimethylformamide (DMF; Wako Pure Chemical Industries, Ltd.) and DMF-d7 (Wako Pure Chemical Industries, Ltd.) were used as received. 1-2 Synthesis Poly(4HCA-co-DHCA)s were synthesized by the two-step reaction in one bottle by the following procedure. Monomers of 4HCA ( g) and DHCA ( g) were mixed and mechanically stirred at 150 o C in the presence of acetic anhydride (40 ml) as a condensation reagent plus sodium acetate (trace) as a transesterfication catalyst, until the solution became homogeneous (for about an hour). The solution was further heated to 200 o C, and the polymerization was carried out for another six hours. The reaction solution increased its viscosity gradually, and became light brown. After the reaction was finished and cooled to room temperature, the materials with a low molecular weight were removed by washing with acetone. The structure of the copolymers was analyzed by NMR and IR studies. The representative 1 H NMR spectrum of the poly(4hca-co-dhca) (DHCA monomer composition: 45 mol %) measured with a NMR spectrometer (JEOL FX 400) at 400 MHz. was shown below. (The 1 H NMR chemical shifts in parts per million (ppm) were recorded downfield from 0.00 ppm using tetramethylsilane (TMS) as an internal reference.) 1 H NMR {400MHz, TFA-d/CD 2 Cl 2 2

3 (1/5 v/v %)}: δ= ppm (acetyl protons), δ= ppm (α-ch), δ= ppm (aromatic protons), δ= ppm β-ch). The detail assignment of aromatic protons is shown in the inset chemical structure. The acetyl groups should be the same amount with DHCA units (45mol%), since the branching was formed at DHCA units. The acetyl proton composition was estimated as 1.6H based on the integral strength ratio to aromatic proton signals (3.5H), which is as high as 1.4H the value calculated from the molar composition of acetyl group (45mol%). Integral strength ratio of vinylene protons 2H to aromatic ones 3.5H agree well with the proton amount ratio in the realistic copolymer structure, showing no side reaction such as heat breakage of vinylene group. Aromatic protons marked as a and a which are adjacent to O-substituted carbons of DHCA showed two or three signals, suggesting the coexistence of coumaryloyl ester and acetyl ester unreacted due to steric hindrance. Then a part of DHCA units form the branching point. H a' H c' H a H b H c O 0.45 O 0.55 CF 3 COOH H a'' H b' H d' O H a H b H d Acetyl group O CH 2 Cl 2 b, b c, c d, d a a a Acetic acid Chemical shift (ppm) 3

4 1-3 Thermotropic properties. The phase transition of Poly(4HCA-co-DHCA)s was observed by a crossed-polarizing microscope (Olympus BX51) equipped with a digital camera. The samples were sandwiched between two glass plates, and were heated at a rate of 10 o C min -1 (resolution: ±0.1K) by a METTLER TOLEDO FP82HT Hot Stage (Greifensee, Switzerland). The glass transition temperature (T g ) and the melting temperature (T m ) were observed by microscopy, and the liquid-crystalline texture was observed under cross-nicols. The microscopic results of the thermotropic behavior were re-confirmed by differential scanning calorimetry (DSC; EXSTAR6100, Seiko Instruments Inc.). 1-4 Mechanical properties. Young s modulus, mechanical strength at break, and strain at break of poly(4hca-co-dhca)s were measured by three-points bending test of the rectangular samples (0.3 x 5.0 x >25 mm 3 ). All tests were carried out at 25 C using a fixed nominal displacement rate of 1mm min -1. The data of at least three samples were averaged. 1-5 Chromatography. The molecular weight of the polymers was determined by gel permeation chromatography (GPC; Shimadzu LC-6A system with a TSK-GEL Super H2000 column), calibrated with polystyrene standards (eluent: dimethylformamide). The products yielded as a result of polymer hydrolysis were analyzed by high performance liquid chromatography (HPLC; Wakopak Navi C18-5, 4.6 x 250 mm) with UV-vis photodiode array detector ( nm). Gradient elution was performed with a 4

5 mobile phase of acetonitrile (solvent B) and 0.1 % H 3 PO 4 in pure water (solvent B): 0-5 min, 10 % solvent B; 5-25 min % solvent B; min 100 % solvent B. Chromatography was performed at 40 o C with a flow rate of 1.0 ml min -1 and injection volume of 5 µl. 1-7 Photoreactivity test. The copolymers were cast from pentafluorophenol solution onto a quartz plate. The glass-filtered high-pressure Hg Lamp (λ>280 nm, 130 mw cm -2 ) was irradiated. The time course of the photoreaction conversion was monitored by UV-visible absorption spectroscopy of the copolymer thin-film. 1-6 In-soil degradation. The rectangular samples (3 mm thick x 5 mm wide x mm long) of poly(4hca-co-dhca)s and poly(bisphenol A carbonate) were buried 10cm deep in the Mt. Aso mountainside (in Minamiaso Village, Kumamoto, Japan). The soil dispersion with 0.1 g ml -1 concentration showed ph=8.0. After 10 months, the changes in shape and weight of each four samples were measured. 5

6 2. Solubility of the copolymers TableS1 Solubility of poly(4hca-co-dhca)s with various composition and corresponding monomers a Solvents monomers C (mol%) b 4HCA DHCA Water c c Ethanol Acetone Acetonitrile Chloroform Pentafluorophenol TFA/DCM (1/ 5 v/v%) d Toluene Hexane N-methylpyrollidinone dimethylsulfoxide N,N -dimethylformamide tetrahydrofuran a) Marks means soluble, insoluble, and partly soluble, respectively. b) C refers to DHCA unit composition in copolymers, estimated by aromatic protons in 1 H NMR spectra. c) Dissolved by heating. d)tfa and DCM refer to trifluoroacetic acid and dichloromethane, respectively. 6

7 3. Semiempirical calculation for one of the most stable conformation of model compounds Diacetyl caffeic acid Di(acetylcoumaryloyl) caffeic acid H: kcal/mol E: 60.2kca/mol H: kcal/mol E: 156.9kca/mol Di(acetylcoumaryloyl coumaryloyl) caffeic acid H: kcal/mol E: 16.7kca/mol Fig. S1 Ball-stick illustrations of one of the most stable conformation for model compounds having the caffeic acid unit, obtained by semiempirical calculation (MOPAC in Chem 3D Ultra Version 8, Cambridge Soft Corporation) using a PM3 hamiltonian to minimize the energy down to a minimum RMS gradient of The initial conformation was determined by pre-calculation using molecular mechanics (MM2) under the condition of a minimum RMS gradient of The heat of formation and steric energy were calculated by MOPAC and MM2, respectively. The heat of formation, H, and steric energy, E, of diacetylcaffeic acid were kca mol -1 and 60.2 kcal mol -1, respectively. On the other hand, the values for di(acetylcoumaryloyl)caffeic acid were kca mol -1 and kca mol -1. The steric hindrance effects on the propagation of 4HCA arms were then investigated. In di(acetylcoumaryloylcoumaryloyl)caffeic acid, the Η was kcal mol -1 higher than di(acetylcoumaryloyl)caffeic acid, whereas the E value was 16.7 kcal mol -1 lower. 7

8 4. Wide angle X-ray diffraction (WAXD) study CA C θ (deg) Fig. S2. Wide angle X-ray diffraction (WAXD) patterns of the poly(4hca-co-dhca)s with various C, recorded on an X-ray diffractometer (RINT UltraX18), equipped with a scintillation counter, using CuKα radiation (40 kv, 200 ma; wavelength = Å), which was monochromated by a parabolic multilayer mirror using transmission geometry. The copolymers were cooled from their T m before the WAXD measurements. Although poly4hca showed several distinct peaks due to the crystals, the copolymers with a C of % and polydhca showed an amorphous halo. The incorporation of the DHCA units rendered amorphous the polymer structure, presumably due to the hyperbranching architecture. 8

9 5. Stress-strain curves C=45 (UV) Stress (MPa) C= Fig. S3. Representative stress-strain curves of the copolymers with C of 45 % measured by three-points bending test. UV refers to the UV-irradiated sample. The polymers were mechanically oriented to form rectangular specimens. The mechanical behavior of these specimens was investigated by a bending test. ε 9

10 6. Infrared spectroscopy change of the copolymer by UV-irradiation (a) C=C stretching (1633cm -1 ) C=C deformation (1312 cm -1 ) (b) Wavenumber (cm -1 ) Fig. S4. Representative FT-IR/ATR spectra of the copolymer with a C=45 % UV-irradiation effects on IR spectra change of the samples after UV-irradiation (b) together with the original state (a). The FT-IR spectra of the copolymers were measured at 25 o C on a Perkin Elmer Spectrum One spectropolarimeter between cm -1. The red arrows indicate the peaks due to the carbon double bonds, which became weak following UV-irradiation. 10

11 7. UV absorption change of the copolymer in the liquid crystalline state by UV-irradiation Abs/Abs Ambient temperature (Crystal state) 250 o C (Liquid crystal state) 310 nm Irradiation time (sec) Fig. S5. The irradiation time dependence of the UV absorption at λ max (around λ=310 nm). UV absorption change of the copolymers as a function of UV-irradiation time at ambient temperature (crystalline state) and 250 o C (liquid crystalline state). The absorption reduction speed in the liquid crystalline state at 250 o C was about twice as high as that in the crystalline state at ambient temperature. 11

12 8. 1 H NMR spectra of the supernatant solution of the degraded copolymer pellets Original sample (in TFA/DCM) Monomer mixture (in D 2 O) Supernatant for 30days hydrolysis (in D 2 O) Supernatant for 30days hydrolysis after 3h UVirradiation (in D 2 O) ppm ppm ppm Fig. S6. A representative 1 H NMR spectra of supernatant solution for the copolymer pellets with a C value of 77 immersed in alkaline solution of ph=10 at 60 o C for 30 days. The 1 H NMR spectra were measured with a NMR spectrometer (JEOL FX 400) at 400 MHz. The 1 H NMR chemical shifts in parts per million (ppm) were recorded downfield from 0.00 ppm using tetramethylsilane (TMS) as an internal reference. The solvent was TFA-d/CD 2 Cl 2 (1/5 v/v %) or D 2 O. The 1 H NMR signals of the supernatant for a sample immersed in an alkaline solution for 30 days were much sharper than those of the original samples, indicating that the dissolution of the samples reduced the molecular weight. The supernatant also showed very small signals for monomers whose intensity was increased by UV-irradiation. 12

13 9. Degradation in soil a b Fig. S7. Photos of the C=45 copolymer samples buried in mountain soil for 10 months. a). Macroscopic digital image. b) FE-SEM image of the sample surface, showing the local cave-in with a micrometer size. Copolymers processed into a rectangle shape were buried in mountain soil (Mt. Aso in Minamiaso Village, Kumamoto, Japan), and the change in shape and weight were measured. Some of the specimens buried for 10 months showed deformation and an 8-13 % weight loss. 13

14 10. Weight change of the copolymer pellet UV-irradiated for various times Weight remaining (wt%) /75 initial 1h UV 3h UV Time (day) Fig. S8. Weight change of the copolymer pellet UV-irradiated for various times when the pellet was immersed in alkaline solution (ph=10) at 60 o C. The pellet (50 mg) for the copolymer with a C of 77 % UV-irradiated for 0, 1 and 3 hours was weighed after immersion in an alkaline buffer solution of ph=10 at 60 o C, and was plotted against the irradiation time. The half-life of the pellet weight decreased from 15 days to 5 days following UV-irradiation for 3 hours. 14