Development of Biodegradable Nylons

合成聚酰胺、尼龙，特别是那些具有相对简单重复单元的聚酰胺、尼龙，通常在自然环境条件下很难通过生物或水解法进行分解。本文研究了由2-吡咯烷酮(1)、己内酰胺和双环内酰胺-8-氧-6-氮杂双环[3，2，1]辛烷-7-酮(2)合成的三种聚酰胺的降解性。在30ﾟ℃下，叔丁醇钾催化1的阴离子聚合得到了高相对分子质量的尼龙4。双环内酰胺2既有五元内酰胺环，也有七元内酰胺环，其在二甲基亚砜中的准活性阴离子聚合得到了单分散、分散良好的聚酰胺，其重复单元中含有四氢吡喃环(3)。将尼龙4、尼龙6和聚酰胺3膜用于几种土壤的埋藏试验，其中大学农场的土壤堆肥超过10年(pH为7.5；土壤1)，同一农场的未堆肥土壤(pH为5)。…More 9；土壤2)、大学校园内的土壤(pH值4.5；土壤3)及其消毒土壤(pH值4.5；土壤4)。其中，尼龙4膜在土壤中分解，4个月后消失。在测试过程中回收的尼龙4的溶液粘度并不与它们的重量损失无关。在pH为7.5的磷酸盐缓冲液中，回收尼龙4膜的重量和溶液粘度均未发生变化。另一方面，在所有的埋藏试验中，聚酰胺3的相对分子质量都有所下降，在酸性土壤中进行了6个月的试验，聚酰胺3的质量也有所下降。土壤1的相对分子质量下降速度与磷酸盐缓冲液(pH为7.5)中的相同。这表明3在土壤中的降解是通过水解进行的。土埋试验后尼龙6溶液粘度恢复L酸性土(土2、土3、土4)略有下降。但在中性条件下，不仅溶液粘度没有变化，而且重量也没有变化。在尼龙6与尼龙4共混膜的土埋试验中，只有尼龙4相被降解，其残留部分与尼龙6形成。根据这些结果，推测尼龙4在农田土壤中是可生物降解的，聚酰胺3是可水解的。事实上，一种放线菌被发现能降解尼龙4薄膜。较少

Synthetic polyamides, nylons, especially those having relatively simple repeating units, are generally hard to be decomposed under natural environmental conditions either through biological or through hydrolytic processes. This research is concerned with the degradability of three kinds of polyamides prepared from 2-pyrrolidone (1), epsilon-caprolactam, and a bicyclic lactam, 8-oxa-6-azabicyclo[3,2,1]octan-7-one (2). The anionic polymerization of 1 catalyzed by potassium t-butoxide at 30ﾟC gave high molecular weight nylon 4. The bicyclic lactam 2 has both of five- and seven-membered lactam-rings and its quasi-living anionic polymerization in dimethylsulfoxide gives a monodisperse and well-dified polyamide having a tetrahydropyran ring in the repeating unit (3). Films of nylon4, nylon6, and polyamide 3 were supplied to soil burial tests in several kinds of soils, the soil composted for more than 10 years in university farm (pH,7.5 ; Soil 1), the noncomposted soil in the same farm (pH,5. … More 9 ; Soil 2), the soil in the campus of the university (pH,4.5 ; Soil 3), and its sterilized soil (pH,4.5 ; Soil 4). Among them, the film of nylon4 was found to be decomposedin Soil and disappeared with 4 months. The solution viscosity of nylon4 recovered during the tests did not irrespective of their weight loss. In a phosphate buffer (pH,7.5) both of weight and solution viscosty of the recovered nylon4 film did not change. Therefore it was degraded probably through biological processes by microorganisms in Soil 1. On the other hand, the molecular weight of polyamide 3 decreased in all the burial tests, and its weight also duced during the tests in the acid soils for 6 months. The decrease rate of the molecular weight in Soil 1 was similar to that in the phosphate buffer (pH,7.5). This suggests that the degradation of 3 in the soils proceeded through the hydrolysis. The solution viscosity of nylon 6 recovered after the soil burial tests l the acid soils (Soil 2, Soil 3, Soil 4) was found to decreases slightly. But in the neutral conditions not only its solution viscosity but also its weight did not change. In the soil burial tests of the nylon6 film blended with nylon4, only the nylon4 phase was degraded and its residual part was formed with nylon6. From these results, nylon4 is inferred to be biodegradable in the farm soil and polyamide 3 to be hydrolyzable. In fact, one of actinimetes was found to degrade nylon4 film. Less