The influences of intramolecular cyclization on the crosslinking reaction processes and the gel′s swelling ratio in polyvinyl alcohol (PVA)-glutaraldehyde(GA) system were studied. The results show that the intramolecular cyclization is a very important factor that has influence on the formation of PVA networks. The lower PVA concentration, the higher intramolecular cyclization degree and higher critical gelation mixing molecular molar ratio of CHO to OH(r_ c ) were obtained . The intramolecular cyclization fractions were increased with the decrease of PVA concentration. Equilibrium swelling ratio decreased with the increase of PVA concentration at the same extent of reaction and the increase of crosslinker concentration at the same PVA concentration. The formation of network can be adjusted with the change of the PVA concentration or the crosslinker concentration.
The core-shell particles consisting of poly(butyl acrylate)(PBA) core and silica shell were synthesized. The 3-methacryloxy propyl trimethoxysilane (MPS) was used as functional comonomer to modify the PBA latex particle surface with silanol(SiOH) groups via semicontinuous emulsion polymerization. The resulted emulsion was transferred into water/ethanol mixture without loss of stability and functionalized PBA latex was used as seeds for further silica shell growth. The coating process was achieved by Stber method, base-catalyzed hydrolysis and condensation of tetraethoxysilane(TEOS). The functionalized latex and core/shell particles were characterized by using differential thermal analysis(DTA), transmission electron microscope and light scattering. It has been confirmed that the PBA latex particles have been entirely enveloped with silica shell and the core/shell particles are monodisperse. The thickness of silica shell can be estimated by the size difference of functionalized PBA-SiO 2 core-shell particles.
