Preparation And Characterization Of Surface Functional Core-shell Latex Particles (PDMS/PMMA)

A novel latex particles of polysiloxane/polymethyl methacrylate (PDMS/PMMA) havingcore-shell structure was successfully synthesized by the pre-emulsion semi-continuous seededemulsion polymerization. Through the introduction of functional monomer ITA, MAH orGMA to realize the function of core-shell latex particles. Which were characterized by thelaser particle size analyzer, means of non-aqueous acid-base titration, Fourier transforminfrared spectroscopy (FTIR) and transmission electron microscope (TEM).The results of the experiments showed that the surface functional PDMS/PMMA core-shelllatex particles was prepared by pre-emulsion semi-continuous seeded emulsionpolymerization. In the synthesis of core PDMS stage, using ultrasonic emulsification method,D4and VD4for pre-emulsification, stirring speed for1000rpm, ultrasonic power wes500w,ultrasonic time was30min, the emulsion particle sizes up to about800nm. The core dosage ofemulsifier was2.46wt%of the core monomers, the dosage of catalyst was2.31wt%of thecore monomers, the mass ratio was3/1of the core monomers, conversion was84.50%of thecore monomers, cross linking agent in the reaction after the half to join, can improve the gelcontent, core gel content reached89.22%, explain PDMS core latex particles for threedimentional polymer.The shell emulsifier dosage of PDMS/P(MMA-ITA) and PDMS/P(MMA-MAH) core/shelllatex particles was0.31wt%of the monomers, the shell emulsifier dosage ofPDMS/P(MMA-GMA) core/shell latex particles was0.62wt%of the monomers. mass ratiowas70/60of core-shell latex particles, The dosage of initiator was0.53wt%of themonomers,and the added manner was2/3in the reactor and another1/3in the shellpre-emulsion. The addition speed of shell pre-emulsion was10mL/h.The results of FTIR, EDS, gel content and non-aqueous acid-base titration indicated thatITA、MAH or GMA indeed copolymerized with MMA in the layer.One part of copolymerlinked with core by chemical bond and another part adsorbed on the surface of core byphysical bond, gel content of surface functional core-shell latex particles (PDMS/PMMA) inthe range70-74%, highest content of functional monomers of surface functional core-shelllatex particles (PDMS/PMMA) in the range1.81-2.12%. By the means of TEM photo and laser particle size analyzer display, that functional latexparticles (PDMS/PMMA) had distinct core/shell structure. Core-shell latex particles wasuniform, shape was round. The results showed that the average particles size of core (PDMS)at around280nm; the average particles size of surface functional core/shell latex particles(PDMS/PMMA) at around320nm.