Development of new environmentally friendly technologies for pulp production by the use of hydrotropic phenomenon

纸浆和造纸工业的未来发展需要开发环境友好的新技术。在这些技术中，应完全避免目前用于纸浆漂白的氯化学品。木质素在纸浆生产的主要阶段制浆和漂白阶段的行为仍然不十分清楚。换句话说，一部分木质素即使在蒸煮结束时也非常耐脱木质素，并且该木质素此后是漂白阶段化学品的目标。因此，若能明确残余木素的抗性，将为制浆漂白开辟一条新的途径。为了观察蒸煮结束时木质素在纸浆表面的再沉淀的贡献，向蒸煮溶液中加入水溶助剂。有趣的是，脱木素程度显著提高，残余木质素量约为常规硫酸盐法蒸煮的一半。这意味着由于再沉淀，一半的残余木质素可能残留在纸浆中，因此开发避免这种现象的技术是极其重要的。原子力显微镜是观察纸浆纤维表面的一种有效手段。在纤维表面上证实了非常细的微纤丝和一些小颗粒，并仔细研究了它们的行为与各种脱木素处理的关系。

It is requisite for the future growth of pulp and paper industries to develop new technologies which are environmentally friendly. In these technologies, chlorine chemicals currently used for the pulp bleaching should be totally avioded.It is still not quite clear how lignin behaves during pulping and bleaching stages which are the main stages for pulp production. In other words, a part of lignin is very resistant against delignification even at the end of cooking, and this lignin thereafter is the target for chemicals at the bleaching stage. Therefore, it will open a new technology for pulping and bleaching, if the resistant nature of residual lignin become clear. In order to see the contribution of re-precipitation of lignin to the surface of pulp at the end of cooking, hydrotropic agent was added to the cooking solution. It was very interesting to note that the degree of delignification was increased remarkably, and the amount of residual lignin became about one half of the normal kraft cooking. This means that half of the residual lignin may be remained in pulp because of re-precititation, and so it is extremely important to develop a technology to avoid this phenomenon. Atomic Force Microscopy was found to be very useful to oberve the surface of pulp fibers. Very fine microfibrils and some small particles were confirmed on the fiber surface, and their behaviors were carefully studied in relation to various delignification treatments.