Study On Poly(4-vinylpyridine-co-butylacrylate)/Poly(Styrene-co-butyl Acrylate-co-sodium Styrene Sulfonate) Composite Microspheres

Polymer composite microspheres with different morphology and particle-size provide a wide range of potential applications in various fields, from paints and organic opacifiers, to impact modifiers for plastics, to carriers for biomaterials and microelectronics materials. The synthesis of novel functional composite micropsheres has attracted more attentions and shown both technological and theoretical importance. In this thesis, we studied the preparation and morphology controlling of Poly(4-vinylpyridine-co-butylacryl ate)/Poly(Styrene-co-butylacrylate-co-sodim styrene sulfonate) [P(4VP-BA)/ P(St-BA-NaSS) ]composite latex system by employing a soapless seeded emulsion polymerization method. The influence of mass ratio of BA to St, mass ratio of NaSS to St, the adding time of NaSS, solvent types, crosslinking angent types and crosslinking degree on the stablilization of soapless seeded emulsion polymerization and the final morphology was studied in great details. The composite microspheres with various morphologies, such as core-shell, inverted core-shell, sandwich-like, dumbbell-shaped, popcorn-like were obtained depending on the polymerization parameters. Especially, we investigated the influence of the ionic monomer NaSS on the stablilization of soapless seededemulsion polymerization and the final morphology, the hypothetical growth mechanism of P(4VP-BA)/P(St-BA-NaSS) composite particles was proposed.1. A series of Poly(4-vinylpyridine-co-butyl acrylate) (P(4VP-BA)) seed latexes were prepared by soap-free emulsion polymerization. The effects of temperature, agitation mode, BA/4VP weight ratio on the stablilization of soapless emulsion polymerization was investigated; and the effects of agitation mode, crosslinking angent types, crosslinking degree, BA/4VP weight ratio on the particle size and its distribution were discussed in detail, the monodisperse latex particles were obtained and suitable for further seeded pre-swelling emulsion polymerization.2. A series of P(4VP-BA)/P(St-BA-NaSS) composite microspheres were synthesized by soapless seeded emulsion polymerization. The effects of BA/St weight ratio, NaSS weight ratio, the adding time of NaSS and solvent types on the stablilization of soapless seeded emulsion polymerization was investigated. It was found that the stablilization of soapless seeded emulsion polymerization was best when BA/St=4/1, NaSS/St=0.125; and the later was the adding time of NaSS, the smaller effect was the stablilization of soapless seeded emulsion polymerization; the stablilization of soapless seeded emulsion polymerization and monodisperse of microspheres was best, water, toluene and n-dodecanol as the solvent, among only water, water and toluene, and water, toluene and n-dodecanol.3. The effect of BA/St weight ratio, NaSS weight ratio, the adding time ofNaSS, solvent types, crosslinking angent types and crosslinking degree on the morphology of the final composite particles were discussed in details, core-shell, inverted core-shell, cellular structured, occluded, snowman or dumbbell-shaped composite particles were produced. It was founded that snowman-shape composite particles was obtained, when the adding time of NaSS was after the separation of composite particles had finished. While core-shell or occluded was obtained, when the adding time of NaSS was during the separation of composite particles.