Research On The Preparation Of Functional Microspheres And Adsorption Protein

Poly(vinyl acetate) (PVAc) macromononer with a vinylbenzyl end group was synthesized by using free radical polymerization in the presence of 2-mercaptethanol as chain transfer agent and end capping reaction with p-chloromethyl styrene. The properties of macromonomer, such as molecular weight, molecular weight distribution, molecule structure and the content of vinyl group were characterized by using gel permeation chromatography (GPC), Fourier transform infrared (FTIR), ultraviolet (UV) and nuclear magnetic resonance (~1H-NMR). The PVAc macromonomer was selected as reaction stabilizer to prepare core-shell composite microspheres. The PVAc grafted polystyrene (PVAc-g-PSt) microspheres were obtained by dispersion copolymerization of styrene (St) with PVAc macromonomer in ethanol/water mixed solvent at some temperature for some time. Molecular structures and composition of PVAc-g-PSt were studied by means of 1H-NMR and X-ray photoelectron spectroscopy analysis (XPS). The PVAc-g-PSt has core-shell structure with PSt as core and PVAc as shell. The morphology and diameter of the microspheres were studied by using scanning electron microscopy (SEM), laser light scattering (LLS) and transmission electronic microscope (TEM). The result indicated that the internal reaction parameters such as molecular weight and [PVAc], [St], [AIBN],external reaction parameters polymerization time, media polarity, polymerization temperature and vibrating rotary speed of constant temperature water bath could affect the diameter and morphology of the PVAc-g-PSt microspheres. Under typical condition PVAc chain number on surface of each PVAc-g-PSt composite microspheres was 1.6×10~3.Poly(vinyl alcohol) (PVA) grafted polystyrene composite microspheres were derived from alkaline hydrolysis from PVA-g-PSt core-shell microspheres. XPS of the microsphere surfaces indicated that PVA chains were favorably located on their surfaces. The functional microspheres was prepared via the nucleophilic action between PVA-g-PSt and Cibacron Blue F3GA(CB). The amount of CB on surface of the functional microspheres was obtained by using an elemental analysis instrument. The adsorption mechanism adsorption time, adsorption kinetic equation, ion strength and pH influence of four typical polymeric microspheres (PSt, PVA-g-PSt, CB functional PVA-g-PSt) for BSA were studied. The interaction was further discussed by characterization of the zeta potential. We do some study about adsorbed layer thicknesses of various microspheres. It is founded that for functional microspheres indicating that BSA exists in an monolayer adsorption and other microspheres indicating that BSA exists in an multilayer adsorption. The highest desorption ratio (95.69 %) was achieved by using an eluent of 0.5 mol/L NaSCN (pH 8.0). The functional PVA-g-PSt microspheres could be reused without significant decreases in the adsorption capacities.These composite microspheres with hydrophilic composite microsphere branches may be used in biomaterial engineering, drug transportation and relief fields.