Study And Characterization Of Adsorption Processes Between Collagen Peptide And Monodisperse PDMS-E Emulsion Particles

In this paper,monodisperse latex particles with different sizes were prepared from?-[3-(2,3-epoxy-propoxy)propyl]-?-butyl-polydimethy siloxanes(PDMS-E)by ceramic membrane emulsification method.The effects of particle size and time scale on the adsorption reaction of PDMS-E latex particles with collagen peptides were studied.The results show that the size of latex particles and reaction time can regulate the adsorption behavior of collagen peptides on the surface of PDMS-E latex particles,and then regulate the interfacial reaction and product morphology.This research will supply experimental data and theoretical foundation for the control of interfacial reactions and polymer morphology between incompatible polymers.PDMS-E modified collagen polypeptide was applied to the functional coating of paper.The results of water resistance,flame retardancy and physical strength tests showed that the morphology of the product had a significant effect on the above properties,and the structure-activity relationship was established.The main results are divided into the following three parts:(1)We use continuous phase dynamic membrane emulsification to prepare monodisperse PDMS-E latex particles in the range of 200-1000 nm,the particle size was adjusted by controlling 0.5 wt% SDS/SDBS mass ratio and the pore size of ceramic membrane.The particle size and dispersion of monodisperse PDMS-E latex particles were characterized by optical microscope and DLS.The adsorption reaction of PDMS-E with collagen polypeptide was studied by fluorescence spectroscopy,Raman spectroscopy and Van Slyke method.The results showed that the adsorption behavior of collagen peptides on the surface of latex particles was affected by reaction time and latex particle size.The size of latex particles can be divided into three scales: ? 410 nm,410-680 nm and ? 680 nm;the time scales include 0-75 min,75-200 min and 200-300 min.Within 0-75 min,collagen polypeptide was mainly physically adsorbed on the surface of latex particles;75-200 min is the competitive stage of physical adsorption and chemical reaction.For the emulsion system of 410 nm,the adsorption and desorption behavior still play a leading role in this time range.For 410-680 nm,this stage is the process of collagen polypeptide adsorbing and accumulating to saturation,and then chemical reaction occurs.For the emulsion system with particle size 680 nm,the chemical reaction plays a leading role in this time range.After 200 min,the primary amino group and epoxy group in the particle size of 410-680 nm and 680 nm emulsion were rapidly consumed,and the graft reaction was stable.(2)The secondary structure and adsorption capacity of collagen polypeptide were determined by Raman spectroscopy and viscosity method.The results showed that the size of latex particles had a significant effect on the secondary structure of collagen peptides.The larger the size of latex particles,the higher the degree of collagen polypeptide spreading on the latex particles,and the higher the content of ?-sheet;on the contrary,the smaller the size of latex particles,the easier the latex particles are to demulsify and desorb,and the collagen polypeptide is not easy to adsorb on the surface of particles,which causes the content of ?-helix to rise and the content of ?-sheet to fall.The viscosity resulting test found that as time went by,the viscosity of each size emulsion system descended.The larger the size,the faster the viscosity decreased and the greater the reduction.This indicated that the larger the size of latex particles,the more grafted collagen polypeptides were on latex particles,and the stability of latex particles increased.The results of TEM showed that the emulsion system of smaller size was more likely to aggregate.The emulsion system of medium size had irregular morphology due to simultaneous adsorption,desorption and chemical reaction.The formation of core-shell structure and multilayer structure was observed in large size emulsion system.(3)The collagen polypeptide modified by PDMS-E was used for paper coating,it can significantly improve the water resistance,flame retardancy,mechanical strength and flexibility of the paper.The effect of the coating on paper properties is related to the size of latex particles.The results show that the larger the size of latex particles,the higher the grafting ratio of PDMS-E and collagen polypeptide,the more orderly the product morphology,the better the dispersion and spreading effect in paper,the better the paper coating performance;but the smaller the size of latex particles,the lower the grafting ratio of PDMS-E and collagen polypeptide,the irregular and uneven product morphology,which cannot be evenly dispersed and spread in paper,the worse the paper coating performance.According to the results and analysis,the structure-activity relationship was established.