Controlling Phase Separation to Spin Cellulose Skin-core Microfiber with Nanosized Multicompartment

Abstract

Phase separation is potential for controlling microcapsule structure. The common problems of capsule shell include worse mechanical properties after releasing the core agent and irregular lasting time of core agent because of the surface cracks during use. The long chain molecular and crossing link of polymer can enhance mechanical properties of capsule shell. Cellulose is a promising polymer altering petrol products with great number of hydrogen bonds and good mechanical properties. In this paper, cellulose as hydrophobic polymer and methyl hexadecanoate as oleophobic agent are blended in DMAc/LiCl solution. Through optical micrography, rheological testing and SEM, the properties of cellulose/ methyl hexadecanoate solution are evaluated and the new structures of cellulose skin-core fiber are characterized. It indicates that methyl hexadecanoate has no interact to cellulose chain, however, methyl hexadecanoate partially induces cellulose entanglement from stable status to irregular status. The obvious phase separation can be controlled to promote emulation capsule forming and well dispersion in solution. By water coagulation, cellulose is easy to form skin-core structure fiber. Meanwhile, methyl hexadecanoate capsules are coated in cellulose core and then cause the multicompartment structure. CN cellulose has great molecular chain as capsule shell to promote stable mechanical properties, even after methyl hexadecanoate releasing. The mechanical stability of the shell accompanied by phase separation is well overcome. This method provides general guideline to synthesize microcapsules with complex structures through phase separation and to make use of the phase separation to control the mechanical behavior of cellulose skin-core structure fiber.