Various substituted lactones, 4-methylene-1,3-dioxolan-2-one, 4,4-dimethyl-5-methylene-1, 3-dioxolan-2-one, 4-methyl-5-methylene-4-phenyl-1, 3-dioxolan-2-one, 4-phenyl-5-vinyl-1,3-dioxolan-2-one, 3-phenyl-4-vinyl-2-oxetanone and 3-methyl-3-phenyl-4-vinyl-2-oxetanone, were prepared and their polymerization behavior were investigated. Polymerization of the above monomers were carried out with common radical initiators such as 2,2'-azobisisobutyro-nitrile, dibenzoyl peroxide, di-t-butylperoxide, dicumyl peroxide or t-butylhydroperoxide. 4-Methylene-1,3-dioxolan-2-one polymerized in neat or in solution to give solid polymer. The conversions were higher in bulk polymerization (78-91% yield) than in solution polymerization (36-62% yield) in that chlorobenzene was used as solvent. The resulting polymers were soluble in dimenthylsulfoxide but insoluble in common organic solvents such as chloroform and acetone. $^1H$-NMR and IR spectral data confirmed that the polymerization proceeded via vinyl type cleanly, thus obtained polymer contained carbonate ring as a pendent group. Hydrolysis of the carbonate ester group of the polymer obtained from 4-methylene-1,3-dioxolan-2-one was carried out with sodium methoxide. The hydrolyzed polymer was soluble in cold water and spectral data indicated that pendent carbonate ring was hydrolyzed leaving hydroxy and hydroxy methyl groups behind. In case of 4, 4-dimethyl-5-methylene-1,3-dioxolan-2-one and 4-methyl-5-methylene-4-phenyl1, 3-dioxolan-2-one, which have alkyl or aryl substituents at 5-position of 4-methylene-1,3-dioxolan-2-one, polymerization did not proceed and the monomers were recovered. However, 4, 4-dimethyl-5-methylene-1, 3-dioxolan-2one, which has less bulky substituents, could be copolymerized in high yield (95%) when vinyl acetate was used as a comonomer. In this copolymerization, 4, 4-dimethyl-5-methylene-1, 3-dioxolan-2-one was also incorporated into the copolymer via addition type reaction. 4-Phenyl-5-vinyl-1, 3-dioxolan-2-one was prepared by insertion of carbon dioxide into 2-phenyl-3-vinyloxirane with tetrakis(triphenyl-phosphine)palladium as catalyst. However, the attempt to polymerize 4-phenyl-5-vinyl-1, 3-dioxolan-2-one with above radical initiators failed.
3-Phenyl-4-vinyl-2-oxetanone was prepared by cyclization of 3-hydroxy-2phenyl-4-pentenoic acid with toluenesulfonyl chloride and pyridine as condensing agent. 3-Methyl-3-phenyl-4-vinyl-2-oxetanone was prepared from 3-hydroxy-2-methyl-2-phenyl-4-pentenoic acid by similar method. Radical polymerization of the two monomers gave solid polymers and spectral data indicated that polymerization proceeded via ring-opening accompanied by elimination of carbon dioxide. The obtained polymers were composed of two kinds of structural repeating units. One was generated by normal ring-opening process and the other by the process, where the rearrangement of the propagating radical was occurred before attacking the next monomer. 3-methyl-3-phenyl-4-vinyl-2-oxetanone, which has more bulky substituent near radical site of ring-opened intermediate, rearranged more seriously.
4-메틸렌-1,3-디옥솔란-2-온, 4,4-디메틸-5-메틸렌-1,3-디옥솔란-2-온, 4-메틸-5-메틸렌-4-페닐-1,3-디옥솔란-2-온, 4-페닐-5-비닐-1,3-디옥솔란-2-온, 3-페닐-4-비닐-2-옥세탄온, 3-메틸-3-페닐-4-비닐-2-옥세탄온 등을 합성하고 이들 단량체들의 라디칼 개시제에 의한 중합거동을 연구하였다. 라디칼 개시제로는 2,2 -아조비스이소부티로니트릴, 디벤조일퍼옥시드, 디-t-부틸퍼옥시드, 디큐밀퍼옥시드, t-부틸히드로퍼옥시드 등을 사용하였다.
4-메틸렌-1,3-디옥솔란을 괴상중합 또는 크로로벤젠에서 용액중합을 시켰을때 고체상의 중합체를 얻었다. 얻어진 중합체는 디메틸설폭시드에는 녹았으나 크로로포름, 아세톤과 같은 보통의 유기용매에는 녹지 않았다. NMR과 IR 데이타로부터 중합은 비닐형태로 진행된 것을 알 수 있었으며, 따라서, 얻어진 중합체는 카르보네이트 고리를 치환기로 가지고 있음을 확인하였다. 이 카르보네이트 치환기를 나트륨 메톡시드로 가수분해 하여 히드록시기와 히드록시메틸기를 생성시켰으며, 얻어진 중합체는 이들 치환기의 친수성으로 인하여 물에 잘 녹았다. 5-위치에 알킬 또는 아틸 치환기를 가지고 있는 4,4-디메틸-5-메틸렌-1,3-디옥솔란-2-온과 4-메틸-5-메틸렌-4-페닐-1,3-디옥솔란-2-온은 그 자체로는 중합이 가지 않았으나 비닐아세테이트와 공중합을 시켰을 때 4,4-디메틸-5-메틸렌-1,3-디옥솔란-2-온은 95% 이상의 높은 수율로 중합이 진행되었다. 이 공중합체에서도 역시 비닐형태의 중합이 이루어졌다. 4-페닐-5-비닐-1,3-디옥솔란-2-온은 테트라키스(트리페닐포스핀)팔라듐을 촉매로 2-페닐-3-비닐옥시란에 이산화탄소를 첨가시켜 합성했다. 이 경우 라디칼 개시제를 사용하여 중합을 시도했으나 중합체는 얻어지지 않았다.
3-페닐-4-비닐-2-옥세탄온과 3-메틸-3-페닐-4-비닐-2-옥세탄온은 각각 3-히드록시-2-페닐-4-펜텐산과 3-히드록시-2-메틸-2-페닐-4-펜텐산을 염화토실과 피리딘을 사용하여 고리화하여 합성했다. 두 단량체를 라디칼 개시제를 사용하여 괴상중합 또는 벤젠이나 크로로벤젠에서 용액중합 시킨 결과 고체상의 중합체가 얻어졌다. 분석결과 중합체에는 옥세탄온 고리가 없으며 여타 카르보닐기도 존재하지 않는 것으로 확인되었다. 이로부터 중합은 비닐 치환체의 이중결합이 고리내로 이동되어 개환이 되면서 이산화탄소가 제거되는 메카니즘에 의해 진행된 것으로 여겨진다.
