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

发展对环境友好的新技术是纸浆和造纸工业未来发展的必要条件。在这些技术中，目前用于纸浆漂白的氯化学品应该完全避免。目前还不太清楚木质素在制浆和漂白阶段的表现，这两个阶段是纸浆生产的主要阶段。换句话说，即使在蒸煮结束时，部分木质素也非常抵抗脱木素，此后这种木质素就成为漂白阶段化学物质的目标。因此，如果残留木素的抗性性质变得清晰，它将为制浆和漂白开辟一条新的技术途径。为了观察蒸煮结束时木质素的再沉淀对纸浆表面的贡献，在蒸煮溶液中加入了助水剂。值得注意的是，脱木素的程度显著增加，残余木质素的量约为正常硫酸盐蒸煮的一半。这意味着，由于重复滴定，剩余木素的一半可能会留在纸浆中，因此开发一种技术来避免这种现象是非常重要的。原子力显微镜被发现是非常有用的观察纸浆纤维的表面。在纤维表面发现了非常细小的微原纤维和一些小颗粒，并仔细研究了它们在各种脱木素处理中的行为。

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.