**3. Depolymerization of poly(olefin sulfone)s**

A sulfonyl group is a strong electron‐withdrawing moiety. The electrons on the carbon atoms adjacent to the SO<sup>2</sup> groups are attracted by SO<sup>2</sup> , and thus, the protons on those carbons are easily removed by base [16]. When a proton on one of these carbons is removed, a chain reaction in which the main chain is depolymerized to the olefin monomer and sulfur dioxide occurs (**Figure 4**). Based on this process, the main chain of the poly(olefin sulfone) decomposes when mixed with bases such as piperidine, methylamine, or triethylamine. One example of base‐induced depolymerization of poly(olefin sulfone)s is reaction of poly(N, N‐diethyl 3‐butenoic amide sulfone) (DEBA) with 4,4'‐trimethylenedipiperidine (base). The 1 H NMR spectrum of DEBA before addition of the base is shown in **Figure 5(a)**. The change in the 1 H NMR spectrum after addition of the base is shown in **Figure 5(b)**. Signals of the olefin protons are easily recognized. In contrast, no change was observed in the DEBA solution without the addition of base, indicating that

olefin monomer (N, N‐diethyl 3‐butenoic amide) is shown in **Figure 5(c)**. A comparison of **Figure 5(b)** and **(c)** showed that the major product in the resulting solution can be attributed

solutions of (a) DEBA, (b) DEBA mixed with 6.15 mmol/L 4, 4'‐trimethylenedipiperidine

**Figure 6.** Photographs of the conc. solution of poly(olefin sulfone)s. The viscosity of the solution decreased rapidly when

H NMR spectrum of the

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Poly(olefin sulfone)s

125

the decomposition of DEBA was caused by the added base. The 1

**Figure 5.** <sup>1</sup>

H NMR spectra of DMSO‐d<sup>6</sup>

a trace of triethylamine was added to the solution.

followed by heating at 100**°**C for 30 min, and (c) a monomer of DEBA.

**Figure 4.** Photoinduced depolymerization of 1:1 alternating poly(olefin sulfone)s containing photo‐base generating groups in the side chain.

is shown in **Figure 5(b)**. Signals of the olefin protons are easily recognized. In contrast, no change was observed in the DEBA solution without the addition of base, indicating that the decomposition of DEBA was caused by the added base. The 1 H NMR spectrum of the olefin monomer (N, N‐diethyl 3‐butenoic amide) is shown in **Figure 5(c)**. A comparison of **Figure 5(b)** and **(c)** showed that the major product in the resulting solution can be attributed

**3. Depolymerization of poly(olefin sulfone)s**

bon atoms adjacent to the SO<sup>2</sup>

124 Alkenes

methylenedipiperidine (base). The 1

groups in the side chain.

base is shown in **Figure 5(a)**. The change in the 1

A sulfonyl group is a strong electron‐withdrawing moiety. The electrons on the car-

those carbons are easily removed by base [16]. When a proton on one of these carbons is removed, a chain reaction in which the main chain is depolymerized to the olefin monomer and sulfur dioxide occurs (**Figure 4**). Based on this process, the main chain of the poly(olefin sulfone) decomposes when mixed with bases such as piperidine, methylamine, or triethylamine. One example of base‐induced depolymerization of poly(olefin sulfone)s is reaction of poly(N, N‐diethyl 3‐butenoic amide sulfone) (DEBA) with 4,4'‐tri-

**Figure 4.** Photoinduced depolymerization of 1:1 alternating poly(olefin sulfone)s containing photo‐base generating

groups are attracted by SO<sup>2</sup>

, and thus, the protons on

H NMR spectrum of DEBA before addition of the

H NMR spectrum after addition of the base

**Figure 5.** <sup>1</sup> H NMR spectra of DMSO‐d<sup>6</sup> solutions of (a) DEBA, (b) DEBA mixed with 6.15 mmol/L 4, 4'‐trimethylenedipiperidine followed by heating at 100**°**C for 30 min, and (c) a monomer of DEBA.

**Figure 6.** Photographs of the conc. solution of poly(olefin sulfone)s. The viscosity of the solution decreased rapidly when a trace of triethylamine was added to the solution.

to the DEBA monomer. **Figure 6** shows a picture of a concentrated solution of a poly(olefin sulfone). Although the viscosity of the solution was very high, when a trace of triethylamine vapor was added to the solution, the viscosity decreased immediately.

Irradiation with 254‐nm light triggered the generation of a base along with creation of a latent image. The visible image could be developed after heating the exposed polymer

Poly(olefin sulfone)s

127

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**Figure 8.** Structures of poly(olefin sulfone)s that generates primary amine by photo irradiation and the photochemical

film.

reactions of the pendant group.
