Novel sintering behavior of polystyrene nano-latex particles in filming process

Filming process of polystyrene nano-latex (NPS) particles was studied by a combination of various methods. For a constant annealing time of 1 h, the A FM images showed that the deformation and sintering temperatures for NPS pa rticles were ca. 90 degreesC and 100 degreesC respectively. In spin-lattice relaxation measurements of solid state NMR, it is found that T-1L, T-1S an d I-1L/I-0 increased significantly after annealing at 90 degreesC and above . DSC results showed that there was an exothermic peak near T-g after annea ling for 1 h at the selected temperatures below 95 degreesC; otherwise, the exothermic peak disappeared after annealing at 100 degreesC or above. The apparent density of NPS increased suddenly in the temperature range. The re sults implied that the macromolecules in NPS particles are in a confined st ate with higher conformational energy and less cohensional interactions whi ch are the drive force for the sintering at a lower temperature compared wi th the multichain PS particles and the bulk polymer.