Chitin was separated inn lean form from skeletal pens of squids and shells by acid and alkali treatment, and acetylchitins of different degree of acetylation were prepared to investigate the film properties as semipermeable membrane. A fully acetylated chitin (degree of acetylation, 2) was prepared by the acetylation of chitin in the presence of perchloric acid with calculated amount of acetic anhydride at 0℃ for 5 hours. Acetylated chitins exhibited increased solubility in formic acid compared with chitin and diacetylchitin was easily soluble even in 85% aqueous formic acid. Acetylchitin films for ultrafiltration study were prepared from formic acid solution by casting on a glass plate and by solidifying in ethanol. Thus prepared films had wet thickness 10-l2μ, and dry thickness 7-8μ, indicating 25% water absorption. Rejection efficiency towards various solutes of different molecular weight including polyethylene glycols, saccharides, amino acid were examined and molecular exclusion limit was found to be about 7,500. This value is smaller than that of chitin films (∼10,000). Measurements of the distribution coefficient for the solutes correlates well with the difference in rejection efficiency toward solutes of similar molecular weights.

완전히 아세틸화된(degree of acetylation: 2) 아세틸키틴을 반투막으로서의 성질을 조사하기 위해 과염소산과 무수초산으로 0℃에서 5시간 반응하여 얻었다. 키틴의 아세틸화는 포롬산에 대한 용해성을 증가시키고 diacetylchitin의 경우 85%의 포름산수용액에서도 쉽게 녹아TEk. 한외여과 실험을 위해 유리판 위에서 포름산에 녹인 1% 아세틸키틴 용액으로 막을 만들었으며 마른막의 두께는 7∼8㎛, 젖은 막의 두께는 10∼12㎛이고 막의 함수율은 25%로 키틴보다 매우 작은 값이다. 여러 가지 분자량에 대한 rejection efficiency는 폴리에틸렌 글리콜, saccharides, 아미노산, 무기염에 대하여 측정하였고 rejection efficiency의 한계는 분자량 7,500으로 순수한 키틴의 10,000보다 작았다. 분자량이 비슷한 경우 rejection efficiency는 막에 대한 친화성의 차이로 분배계수를 측정하여 알 수 있었다. 아세틸키틴막에서 saccharide, 아미노산이 폴리에틸렌 글리콜류보다 친화성이 좋아 rejection efficiency가 작고 무기염인 경우 실제의 수화된 이온반경이 크게 작용하여 유기용질보다 컸다.