A Fully Aromatic High Performance Thermoset via Sydnone- Alkyne Cycloaddition

Transcription

1 A Fully Aromatic High Performance Thermoset via Sydnone- Alkyne Cycloaddition Nisha V. Handa,, Shaoguang Li,, Jeffrey A. Gerbec,, Naoko Sumitani, # Craig J. Hawker *,,, *,, ǁ and Daniel Klinger Mitsubishi Chemical Center for Advanced Materials, Department of Chemistry and Biochemistry, Materials Department, and Materials Research Laboratory, University of California, Santa Barbara, CA. ǁ Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Str. 2-4, Berlin, Germany Mitsubishi Chemical USA, Inc., Chesapeake, Virginia 23320, United States, # Mitsubishi Chemical Group Science and Technology Research Center, Inc., Yokohama , Japan. Supporting Information Table of Contents Experimental details...s2 Monomer synthesis...s3 Model compound synthesis...s7 Investigations on regioselectivity of model compound S7 Oligomer preparation and characterization..s8 Thermoset preparation: investigation on curing condition.s18 DMA and TMA analysis of TS...S20 Adhesion strength of TS on aluminum substrate....s21 SI References..S21 S1

2 EXPERIMENTAL DETAILS Materials. p-phenylenediamine (>99%), ethyl bromoacetate (98%), anhydrous sodium acetate (>99%), sodium nitrite (99.5%), trifluoroacetic anhydride (>99%), 1,3,5-triethynylbenzene (97%), phenylacetylene (98%), and anhydrous N-methyl-2-pyrrolidone (99.5%) were used as received from Sigma-Aldrich. N-phenyl sydnone was prepared following the literature procedure. 1 1,3-diphenyl-1Hpyrazole (MO) was synthesized following a modified literature procedure. 2 Sodium sulfate anhydrous (99%), sodium chloride (>99%), sodium hydroxide, ethanol, dichloromethane and acetic acid were obtained from Fisher Scientific. Characterization NMR measurements were performed using Varian unity inova 500 and 600 MHz instruments. All samples were dissolved in either CDCl 3 or DMSO-d 6. Mass spectrometry was performed on a quadrupole/time-of-flight tandem mass spectrometer (ESI) or a time-of-flight mass spectrometer (EI and FD). IR spectra were recorded using an attenuated total reflectance (ATR) sampling accessory. Determinations of molecular weights were performed by GPC in DMF with 1% LiBr on a Waters 2695 Separation Module equipped with a Waters 2414 refractive index detector and Waters 2996 Photodiode Array detector. Molecular weights were determined against polystyrene standards. Differential scanning calorimetry (DSC) was performed on a TA Instruments Q2000 DSC system at a heating rate of 10 C /min under a nitrogen atmosphere. Thermal stability was evaluated using a Mettler Toledo TGA/SDTA 851 with a heating rate of 10 C /min under nitrogen and air. Dynamic mechanical thermal analysis (DMTA) was performed on a Q800 DMA (TA Instruments) with a sample size of mm. The storage modulus E, loss modulus E and tan δ were determined at a programmed heating rate of 3 C/min at a frequency of 1 Hz from C. Glass transition temperature (T g ) was determined as the peak temperature of tan δ and loss modulus curves accompanied by a decrease of storage modulus. The thermomechanical analysis (TMA) was performed on Q400 TMA (TA Instruments) in tension mode with static loading of 0.4 N. The coefficient of thermal expansion (CTE) for TS was measured in the range from C. S2

3 Monomer Synthesis Synthesis of Phenyl bissydnone (BS) Scheme S-1. Optimized high yielding synthetic procedure for BS. Synthesis of N,N'-1,4-phenylene bis-1,1'-diethyl ester (1a). 1,4-diamino benzene (50 g, 0.46 mol) was introduced to a two necked 2 L flask equipped with a water condenser, argon gas balloon and teflon coated stir bar. Anhydrous ethanol (500 ml, 0.9 M) was added to the flask followed by the addition of ethylbromoacetate (101 ml, 0.96 mol) and sodium acetate (152 g, 1.85 mol). The resulting mixture was refluxed at 80 C for 4-5 h under argon atmosphere. The reaction mixture was allowed to cool down to ~ 50 C followed by the addition of deionized (DI) water (~ 200 ml) slowly until the solution became clear. The resulting brown colored clear solution was cooled down to 0 C in fridge for 12 h, which resulted in the crystallization of pure compound as brown colored needle shaped crystals. The crystals were filtered using Buchner filter and dried (60 g, 46% yield). 1 H NMR (600 MHz, CDCl 3 ) : δ 6.56 (s, 4H), 4.22 (q, J = 7.1 Hz, 4H), 3.84 (s, 4H), 1.28 (t, J = 7.1 Hz, 6H); 13 C NMR (151 MHz, CdCl 3 ) : δ , , , 61.30, 47.21, 14.34; MS (ESI) for C 14 H 20 N 2 O 4 [M+Na + ]: calcd , found ; IR ν max (cm -1 ) : 3389, 2983, 2902, 1742, 1529, 1449, 1375, 1301, 1250, 1207, 1157, Synthesis of N,N'-1,4-Phenylenediglycine (1b). Compound 1a (60 g, 0.21 mol) was introduced to a 1 L flask equipped with a water condenser and magnetic stir bar followed by the addition of ethanol (85 ml, 2.5 M). The reaction mixture was stirred at room temperature and DI water (666 ml, 0.3 M) and NaOH (25 g, 0.63 mol) were added. The resulting mixture was refluxed at 100 C for 30 min or until the solution become clear. After the reaction was complete, the reaction mixture was allowed to cool down to room temperature and acidified to ph 1 by dropwise addition of dil. HCl. During acidification, compound 1b precipitated out of the solution as grey colored solid. It was collected by filtration and dried under vacuum (56 g, 88%). The product was used as such for the next step. 1 H NMR (500 MHz, DMSO- d 6 ): δ 6.94 (s, 4H), 3.96 (s, 4H); 13 C NMR (125 MHz, DMSO- d 6 ): δ 173.5, 140.2, 114.1, 46.3; MS (ESI) for S3

4 C 14 H 20 N 2 O 4 [M+H + ]: calcd , found ; IR ν max (cm -1 ): 3451, 2910, 2704, 2560, 2402, 1750, 1506, 1409, 1221, 878. Synthesis of N,N -Dinitroso-p-phenylenediamine-N,N -diacetic acid (1c). A stirred solution of N,N'-1,4- Phenylenediglycine 1b (55g, 0.18 mol) in glacial acetic acid (462 ml, 0.43 M) was cooled to 0-5 C followed by the drop wise addition of an aqueous solution of sodium nitrite (39 g in 435 ml water) over a period of 1h while maintaining the temperature between 0-5 C. After the complete addition, the solution turned from black to bright yellow. Stirring was continued at the same temperature for an additional hour followed by acidifying the solution to ph 1 using conc. HCl. The solution color changed from bright yellow to red. After stirring at 0 C for 10 min, compound 1c precipitated out of the reaction mixture as light yellow solid. The solid product was filtered, dried (40.5 g, 77% yield) and used as such for the next step. 1 H NMR (600 MHz, DMSO- d 6 ): δ (s, 2H), 7.78 (s, 4H), 4.81 (s, 4H); 13 C NMR (125 MHz, DMSO-d 6 ): δ 167.6, 140.7, 121.2, 47.2; IR ν max (cm -1 ): 3100, 3005, 2962, 2651, 1720, 1501, 1455, 1419, 1402, 1296, 1254, 1227, 1140, 930; TOF MS ESI, Calcd for C 10 H 10 N 4 O 6, [2M+Na] , [3M+Na] , [4M+Na] ; found, , , Synthesis of phenyl bissydnone (BS). Compound 1c (40 g, 0.14 mol) was introduced into a two necked 500 ml flask equipped with a water condenser and an argon balloon followed by the addition of dichloromethane (252 ml, 0.5 M). Triflouroacetic anhydride (131 ml, 0.94 mol) was slowly added to the reaction mixture at 0 C. After complete addition, the reaction mixture was refluxed at 45 C for 1 h. The resulting clear solution was poured into ice-cold water (~ 700 ml), leading to the precipitation of the product as yellow solid. The solid was filtered, washed with water and cold ethanol and dried under vacuum (30.7 g, 88% ). 1 H NMR (500 MHz, DMSO- d 6 ): δ 8.28 (s, 4H), 7.93 (s, 2H); 13 C NMR (126 MHz, DMSO-d 6 ): δ 168.4, 136.7, 123.6, 95.6; IR ν max (cm -1 ): 3118, 1750, 1525, 1473, 1289, 1248, 1185, 1096, 1008, 953, 850, 736; TOF MS FI, Calcd for C 10 H 6 N 10 O 4, [M] ; found, ; TOF MS ESI, Calcd for C 10 H 6 N 10 O 4, [2M+Na] ; found, S4

5 Synthesis of diphenylether-4,4'-bissydnone (BS-2) Scheme S-2. Synthetic strategy employed to prepare another bis sydnone derivative BS-2 possessing a diphenyl ether linkage Synthesis of 4,4'-bis-(ethoxycarbonylmethyl-amino)-diphenyl-ether (2a). 1,4-diamino benzene (80 g, 0.40 mol) was introduced to a two necked 2 L flask equipped with a water condenser, argon gas balloon and teflon coated stir bar. Ethanol (500 ml, 0.8 M) was added to the flask followed by the addition of ethylbromoacetate (93 ml, 0.84 mol) and sodium acetate (150 g, 1.83 mol). The resulting mixture was refluxed at 75 C for 4 h under argon atmosphere. The reaction mixture was allowed to cool down followed by the addition of deionized (DI) water (~ 200 ml) slowly until the solution became clear. The resulting brown colored clear solution was cooled down to 0 C for 12 h, which resulted in the crystallization of pure compound as light yellow crystals. The crystals were filtered using Buchner filter and dried (97 g, 65%). 1 H NMR (500 MHz, CDCl 3 ) : δ 6.84 (d, J = 10.0 Hz, 4H), δ 6.56 (d, J = 10.0 Hz, 4H), 4.23 (m, 4H), 4.14 (s, 2H), 3.87 (s, 4H), 1.29 (m, J = 5.1 Hz, 6H); 13 C NMR (125 MHz, CDCl 3 ) : δ 171.2, 150.4, 142.8, 119.6, 114.1, 61.3, 46.5, 14.2; MS (ESI) for C 20 H 24 N 2 O 5 [M+Na + ]: calcd , found ; IR ν max (cm -1 ) : 3387, 2985, 1742, 1529, 1375, 1302, 1250, 1211, Synthesis of diphenylether-4,4'-diglycine (2b). Compound 2a (95 g, mol) was introduced to a 1 L flask equipped with a water condenser and magnetic stir bar followed by the addition of ethanol (80 ml, 3.2 M) and 700 ml 1 M NaOH solution. The resulting mixture was refluxed for two hours and the reaction mixture was allowed to cool down to room temperature and acidified to ph 1 by dropwise addition of dil. HCl. During acidification, compound 2b precipitated out of the solution as grey colored solid. It was collected by filtration and dried under vacuum (73 g, 90%). 1 H NMR (500 MHz, DMSO- d 6 ): S5

6 δ 9.01 (s, broad, 2H), 6.70 (d, J = 8.5, 4H), 6.51 (d, J = 8.5, 4H); 13 C NMR (125 MHz, DMSO- d 6 ): δ 173.2, 149.1, 144.4, 119.4, 113.5, 45.6; MS (ESI) for C 16 H 16 N 2 O 5 [M+Na + ]: calcd , found ; IR ν max (cm -1 ): 3455, 2908, 2710, 2560,1752, 1511,1225, 878. Synthesis of 2,2'-((oxybis(4,1-phenylene))bis(nitrosoazanediyl))diacetic acid (2c). A stirred solution of N,N'-1,4-Phenylenediglycine 2b (72g, 0.23 mol) in 500 ml glacial acetic acid was cooled by ice-water bath followed by the drop wise addition of an 1M solution of sodium nitrite (600 ml) over a period of 1h while maintaining the temperature between 0-5 C. After the complete addition, the solution turned to brown. Stirring was continued at the same temperature for an additional hour followed by acidifying the solution to ph 1 using conc. HCl. The solution color changed to red and compound 2c precipitated out of the reaction mixture as light yellow solid. The solid product was filtered, dried (47 g, 55%) and used as such for the next step. 1 H NMR (500 MHz, DMSO- d 6 ): δ (s, 2H), 7.66 (d, J = 8.5, 4H), 7.24 (d, J = 8.5, 4H), 4.75 (s, 4H); 13 C NMR (125 MHz, DMSO-d 6 ): δ 167.6, 156.2, 137.6, 122.7, 120.0, 47.8; IR ν max (cm -1 ): 3110, 2965, 2645, 1725, 1501, 1415, 1293, 1255, 1221, 930; TOF MS ESI, Calcd for C 16 H 14 N 4 O 7, [M] , [2M] ; found, , Synthesis of diphenylether-4,4'-bissydnone (BS-2). Compound 2c (46 g, 0.12 mol) was suspended in 250 ml dichloromethane and cooled down to 0 C. Triflouroacetic anhydride (131 ml, 0.94 mol) was added by dropwise into the reaction mixture, After complete addition, the reaction mixture was refluxed at 45 C for 1 h. The resulting clear solution was poured into copious amount of crushed ice and bissydnone BS-2 was obtained as orange solid. The solid was filtered, washed with water and cold ethanol and dried under vacuum (37.5 g, 90% ). 1 H NMR (500 MHz, DMSO- d 6 ): δ 8.01 (d, J = 9.0, 4H), 7.77 (s, 2H), 7.42 (d, J = 9.0, 4H); 13 C NMR (125 MHz, DMSO-d 6 ): δ 168.9, 158.9, 130.9,124.4, 120.7, 95.4; IR ν max (cm -1 ): 3110, 1713, 1697, 1671, 1469, 949; TOF MS ESI, Calcd for C 16 H 10 N 4 O 5, [2M+Na] ; found, S6

7 Model Compound Synthesis Synthesis of MO H N N N O N O + H NMP 185 o C, 2 days N N N N H MO Scheme S-3. Synthetic strategy for model compound MO A mixture of N-phenyl sydnone (203 mg, 1.25 mmol) and 1,3,5-triethynylbenzene (38 mg, 0.25 mmol) in anhydrous NMP (1 ml) was stirred at 185 C for 2 days. Subsequently, the reaction mixture was cooled down to room temperature and purified by column chromatography using hexane: ethyl acetate (10:1, v/v) as eluent to obtain the compound as a pale powder (40 mg, 32% yield). 1 H NMR (400 MHz, DMSOd6): δ 8.63 (d, J =2.4 Hz, 3H), 8.41 (m, 3H), 7.97 (d, J = 7.6 Hz, 6H), 7.53 (t, J = 8.0 Hz, 6H), 7.33 (t, J = 6.4 Hz, 3H), 7.25 (d, J =2.4 Hz, 3H); 13 C NMR (126 MHz, DMSO-d 6 ): δ 152.1, 140.1, 134.2, 130.0, 126.8, 122.6, 118.9, 106.4; TOF MS FD for C 33 H 24 N 6 [M]+: calcd , found Investigations on regioselectivity of model compound Figure S-1. 1 H-NMR investigation on the crude reaction mixture of the model compound show a clear preference of the 3-substituted pyrazoles: the molar ratio of 3- to 4-substituted isomers is 10:1. S7

8 Oligomer Preparation Synthesis of pyrazole-oligomers (OL): Phenyl bis-sydnone BS (0.25 g, 0.99 mmol) and 1,3,5-triethynyl benzene TA (0.1 g, 0.66 mmol) were dissolved in degassed NMP ( 5 ml, 0.13 M). The resulting mixture was stirred at 150 C for 24 h. Afterwards, the reaction mixture was allowed to cool down to room temperature followed by the addition of methanol until the product precipitated out of the solution. The resulting solid was filtered and dried (Yield: 0.2 g). 1 H NMR (500 MHz, DMSO-d 6 ): δ (m, 1H), (m, 6H), (m, 2H), (m, 16H), (m, 1H), 7.54 (dd, J = 8.4, 6.0 Hz, 1H), (m, 2H), (m, 2H); IR ν max (cm -1 ): 3297, 1748, 1671, 1607, 1527, 1050, 946. Figure S-2. Investigations on the presence of reactive groups and cross-linking points in the precursor oligomers through comparisons of the 1 H NMR spectra of OL with their corresponding model compound (MO) and starting monomers (BS and TA). S8

9 GPC analysis of OL: GPC analysis shows the disappearance of phenyl bis-sydnone BS and the appearance of new peaks corresponding to OL thus indicating complete incorporation of monomers into oligomers at 150 C for 15 h (Figure S-3). The number average molecular weight (M n ) was found to be in the range of 4 kda (Table S-1). Figure S-3. GPC traces for phenyl bis-sydnone BS and oligomer OL Table S-1. GPC data for low molecular weight oligomers OL Reaction condition M n (Da) M w (Da) PDI 150 C _ 15 h 4 k 12 k 3 S9

10 Thermogravimetric Analysis of OL: TGA analysis of oligomers OL showed an initial loss starting at ~ 170 C followed by final degradation at 480 C (Figure S-4). Since this can most likely be attributed to the CO 2 evolution from the cycloaddition reaction of free sydnone and alkyne moieties, it demonstrates the potential of oligomer OL for further cross linking. Figure S-4. The TGA data for OL showing losses prior to final degradation. S10

11 Synthesis of pyrazole-oligomers (OL-a): Phenyl bis-sydnone BS (0.20 g, 0.53 mmol) and tris-alkyne benzene TA-2 (0.2 g, 0.79 mmol) were dissolved in degassed NMP ( 4 ml, 0.13 M). The resulting mixture was stirred at 170 C for 15 h. Afterwards, the reaction mixture was allowed to cool down to room temperature followed by the addition of methanol until the product precipitated out of the solution. The resulting solid was filtered and dried. Scheme S-4. Synthetic strategy used for the preparation of oligomers OL-a. Table S-2. Reaction conditions used to prepare oligomer OL-a Temperature Molarity Time Results ( C) (M) (h) No reaction No reaction No reaction No reaction No reaction A very slight amount of oligomer and unreacted monomers Oligomer S11

12 Figure S-5. Stacked 1 H NMRs for the starting monomers and resulting oligomers OL-a. As shown in Figure S-5, both oligomers possessed new peaks along with the reduction of monomers, indicating the completion of reaction. The oligomers prepared was in the range of M n = 1.5 kda (Table S- 3). Table S-3. GPC data for oligomers OL-a Compound M n (Da) M w (Da) PDI Oligomer OL-a 1.5k 2.2k 1.4 S12

13 Synthesis of oligomer OL-b: 3,3 -(4,4 -Diphenyl)bissydnonyl ether BS-2 and 1,3,5-triethynyl benzene TA (Scheme S-5) were reacted together in NMP under inert conditions at 150 C using different molarity of reaction mixture as listed in Table S-4. Complete polymerization was observed at 150 C for 12 h at 0.33 M of reaction mixture, which resulted in the generation of an insoluble fully cross-linked polymer. Full crosslinking under these reaction conditions was believed to be due to high concentration of the reaction mixture used. In contrast, reducing the molarity of reaction to 0.11 M resulted in the preparation of soluble low molecular weight oligomer, which was soluble in polar solvents such as DMSO, DMF etc. Scheme S-5. The strategy for oligomer OL-b preparation Table S-4. Conditions used for oligomer preparation Temperature ( C) Time (h) Molarity (M) of reaction mixture Results Fully cross-linked polymer (insoluble) Incomplete Reaction Oligomer (soluble) S13

14 1 H NMR data The oligomer OL-b was characterized using 1 H NMR. As shown in Figure S-6, the reduction of monomer peaks along with the appearance of new peaks confirms the formation of oligomer. The protons at δ 8.5 ppm indicate towards the pyrazole protons formed after cycloaddition reaction between sydnone and alkyne. Figure S-6. Stacked 1 H NMR spectra for starting monomers and oligomer OL-b Synthesis of oligomer OL-c 3,3 -(4,4 -Diphenyl)bissydnonyl ether BS-2 and 1,3,5-tris(phenylethynyl) benzene TA-2 (Scheme S-6) were allowed to react together in degassed NMP at temperatures ranging from 100 C C for h, as listed in Table S-5. While no reaction was observed at T 150 C, low molecular weight soluble oligomer was obtained at both 170 and 180 C for 15 h at 0.26 M. In contrast, high temperature (200 C ) at 0.13 M resulted in a high molecular weight oligomer, which was sparingly soluble in polar solvents such as DMSO, DMF etc. S14

15 Scheme S-6. The strategy for oligomer OL-c preparation. Table S-5. Conditions used for oligomer preparation Temperature ( C) Time (h) Molarity (M) of reaction mixture Results No Reaction No Reaction No Reaction Oligomer (soluble) Oligomer (soluble) High molecular weight oligomer (sparingly soluble) S15

16 1 HNMR data As shown in Figure S-7, the oligomer OL-c possesses new peaks along with the reduction of starting 3,3 -(4,4 -Diphenyl)bissydnonyl ether BS-2 and 1,3,5-tris(phenylethynyl)benzene TA-2, confirming the successful preparation of oligomer OL-c. All peaks at δ > 8.5 ppm corresponds to the protons from pyrazole ring formed after the 1,3-dipolar cycloaddition reaction of sydnone and alkyne moieties. Figure S-7. Stacked 1 H NMR spectra for starting monomers and oligomer OL-c S16

17 GPC data As per GPC data, the disappearance of 1,3,5-tris(phenylethynyl)benzene TA-2 and appearance of new peak corresponding to oligomer OL-c suggest the completion of reaction at both 170 and 180 C for 15 h. The number average molecular weight (M n ) was found to be in the range of kda (Figure S-8, Table S-6). Table S-6. GPC data for oligomer OL-c Reaction conditions M n (Da) M w (Da) PDI 170 C _ 15 h 3.5 k 10 k C _ 15 h 2.7 k 6.2 k 2.3 oligomer@170 C_15h oligomer@180 C_15h Trisalkyne benzene RT (min) Figure S-8. different conditions GPC for 1,3,5-tris(phenylethynyl)benzene TA-2 and oligomer OL-c prepared under S17

18 Thermoset Preparation Thermal Curing of Precursor Oligomers Polypyrazoles based thermoset (TS). In a 1 dram vial 300 mg of OL was mixed with 550 mg of NMP, the vial was capped and placed in a centrifugal mixer. After 5 minutes at 3,500 rpm, a 35 wt-% oligomer slurry was obtained and drop cast on the respective substrate. The coated substrate was then placed for 2 h on a preheated hot plate at 150 C to remove the solvent. The dried film was then cured by the following step wise heating protocol: 200 C for 5h, 200 C for 5 h C for 5 h and 200 C for 5 h C for 5 h C for 5 h. After cooling to room temperature black-brown colored films of TS was obtained. Investigations on the Curing Behavior of TS using TGA In order to investigate the influence of curing conditions on the cross-linking conversion, three films of OL were prepared as described above. The effect of curing temperature was investigated by removing the films from the curing procedure after three different stages: after 200 C for 5h, 200 C for 5 h C for 5 h and 200 C for 5 h C for 5 h C for 5 h. Samples of the films were then investigated by TGA and it was found that the films after the 200 and 250 C steps still exhibited a series of successive losses prior to thermal degradation. Most likely, this can be attributed to CO 2 evolution from the cycloaddition between the respective free reactive groups, thereby demonstrating an incomplete crosslinking. Upon enhancing the cure temperature to 300 C for 5 h, no successive losses were observed in the TGA data of TS, indicating the complete crosslinking and requirement of a final curing step at 300 C (Figure S-9) Weight % C_5h (OL) 200 C_5h C_5h (OL) 200 C_5h C_5h C_5h (OL) Temperature ( C) Figure S-9. TGA investigations on the influence of curing temperatures on the thermal properties of oligomer films: Samples after the 200 C for 5 h, 200 C for 5 h C for 5 h and 200 C for 5 h C for 5 h C for 5 h curing steps. S18

19 FT-IR analysis graph for TS preparation: Figure S-10. FT-IR analysis of oligomer OL and thermoset TS. Thermal stability of thermoset polymers: Figure S-11. Thermal stability data for all reported thermoset polymers under air. S19

20 Thermomechanical Analysis (TMA) and Dynamic Mechanical Analysis (DMA) of TS Sample preparation - free standing thermoset films. Free standing film of the thermoset polymer was prepared by slight variations of the above described curing method: the oligomer slurry was drop cast on a standard borosilicate microscopy slide. After the initial drying step for 2 h at 150 C on a hot plate, the film was peeled of the substrate with a razor blade. The free standing sample was then pressed between two glass slides using a standard binder clip and was subjected to the previously described standard curing protocol giving thermoset samples with a thickness of around mm. The resulting thermoset TS was cut into the samples of well defined dimension using a double razor blade. Thermomechanical analysis (TMA). Sample dimension for TS was 16 mm (l) x 4.2 mm (w) x 0.14 mm (h). The results are shown in Figure S-12. Figure S-12. Thermomechanical analysis of free standing thermoset film of TS: dimensional change of samples as function of temperature. Dynamic mechanical analysis (DMA). Sample dimension for TS was 13 mm (l) x 4 mm (w) x 0.14 mm (h). S20

21 Adhesion Analysis. Lap Shear test. Lap shear test was performed on aluminum substrate as follows: unpolished aluminum substrate (5052 H32) of 7.5 cm 2.5 cm was cleaned by rinsing with hexanes, ethanol, acetone, and deionized water followed by air drying for 12 h. The B-staged oligomers (OL) in NMP (55% wt., 20 µl) was applied to an overlapped surface of cm in a lap shear configuration. Binder clip was used to ensure the alignment of surface and maintain contact while curing. The oligomer was cured in an oven under air following a ramped cure to C/min followed by maintaining the temperature at 300 C for 5 h to ensure complete curing. The substrate was pulled in a tension at a crosshead speed of 0.2 mm/min until failure. The lap shear strength value was acquired by dividing the maximum load at failure by the adhesive overlap area. Each sample was tested a minimum of 5 times, averaged, and reported with error bars. Table S-7. Thermal, thermomechanical and adhesion properties of TS Therm osets TGA DSC DMA TMA Lap Shear test T d5% T d5% wt. loss at T g T g T β CTE Adhesion ( C) a ( C) b 300 C a ( C) c ( C) d ( C) d (µm/(m. C) strength (MPa) TS wt%/h > e, 480 f 70 g, 70 h 47.5 i 2.5 ± 0.9 J a: measured in N 2 ; b: measured in air; c: measured by DSC at a heating rate of 10 C/min; d: measured by DMA at a heating rate of 3 C/min; ; e: Tan δ maximum; f: maximum of E ; g: subglass transition measured from tan δ; h: subglass transition measured from E ; i:cte recorded from C; j: measured on aluminum substrate. References 1. Earl, J. C.; Mackney, A. W., J. Chem. Soc., 1935, Browne, D. L.; Taylor, J. B.; Plant, A.; Harrity, J. P. A., J. Org. Chem., 2010, 75, S21