Fabrication of phase change microcapsules with controllable size via regenerated nanochitin stabilized pickering and their applications for lyocell fiber

Lyocell fiber has attracted much attention in the textile fields as a greener alternative to viscose. Thermo-regulating Lyocell fiber, which composited with phase change materials (PCMs) and Lyocell fibers, would be desirable for making smart clothing with improved comfort. Herein, microencapsulated phase change materials (MPCMs) with polyurea shell and n-octadecane as core material were fabricated using regenerated nanochitin (RCh) as stabilizer via Pickering emulsion strategy. The size of MPCMs can be controlled by a tunable oil/water mass ratio (O/W). When the O/W ratio was above 1/25, the MPCMs exhibited melting enthalpy as high as 189.92 J/g with average size of less than 5 µm, which was suitable for spinning thermo-regulating Lyocell fibers. The thermo-regulating Lyocell fibers that were fabricated by a dry-jet wet spinning process showed high heat capacity (21.07 J/g) with a diameter of about 30 µm at 20 % loading microcapsules. They demonstrate good durability, where 95 % of the original heat capacity were retained after 100 heating/cooling cycles.