Study On The Synthesis And Application Of Polymer-Supported Initiator Assisted By UV Radiation

In the current paper,polyacrylic acid was grafted onto backbone of several polymer substrate,such as P(S-DVB)microspheres,P(S-DVB)sodium sulfonate mierospheres and polypropylene non-woven fabrics,by the surface grafting polymerization induced by UV radiation.Several effect factors of the radiation grafting were investigated,including formulation of soaking solution,time and distance of the radiation.The optimum condition could be given as follow:â‘ ratio of dispersant and solvent 1/1,concentration of acrylic acid 50%,concentration of initiator A 25 g/L,concentration of initiator B 0.75 g/L, radiated by using 700W metal halide lamp(radiation distance 20cm,and radiation time 1.5h), the maximum grafting rate for the P(S-DVB)microspheres could approach 68.3%;â‘¡ratio of dispersant and solvent 3/2,concentration of acrylic acid 50%,concentration of initiator A 25 g/L,concentration of initiator B 0.75 g/L,radiated by using 700W metal halide lamp (radiation distance 15cm,and radiation time 1h),the maximum grafting rate for the sodium sulfonate microspheres could approach 52.6%;â‘¢ratio of dispersant and solvent 1/1, concentration of acrylic acid 50%,concentration of initiator A 25 g/L,concentration of initiator B 0.5 g/L,radiated by using 500W mercury lamp(radiation distance 15cm,and radiation time 1.5h),the maximum grafting rate for the polypropylene non-woven fabrics could approach 1321%,the grafted polymers obtained by UV radiation could be changed to polymer supported peroxy acid in mixture of hydrogen peroxide and peroxy acid accelerator,as initiators for the subsequent grafting polymerization.The results showed that the concentration of polymer-supported peroxyacid could approach maximum value when the ratio of hydrogen peroxide and accelerator was 25:18.We also research the grafting polymerization of several monomers,such as acrylic acid(AA),acrylamide(AM)and mixture of AA and AM,initiated by polymer-supported initiators synthesized in preceding step.The polymerization of acrylic acid and acrylamide grafted onto polypropylene non-woven fabrics by using the polymer-supported peroxyacid redox system as an initiator were studied emphatically.The influences of reaction time,reaction temperature, concentration of monomer and polymer-supported peroxyacid on graft polymerization were discussed in depth as well.Finally,the polymerization kinetics of acrylamide grafted onto polymer was also discussed,the graft polymerization rate could be expressed as R_g= K[M][RCOOOH]^1/2in the early stage of the reaction,the apparent activation energy of graft polymerization is 8.103KJ/mol,the rate costant of graft polymerization is 5.100×10^-3L/mol·s and 5.125×10^-3L/mol·s when the concentration of monomer and polymer supported preoxyacid mantainning a constant,respectively.The content of carboxyl group were determined for all the resultant grafted polymer, and some of them were characterized by using FTIR and SEM techniques.The results revealed that the predetermined monomers were grafted onto the corresponding polymer substrate,and causing more changes of surface morphlogy in the substrates.Swelling behaviors of resultant grafted polymers were investigated in different aqueous solution by varying its temperature,pH value and type of dissolved salts,the swelling ratios of the grafted polymers changed with solution temperature,followed the laws of pyrocondensation.And all the grafted polymers,especially that of acrylic acid,had obvious response to the changes of pH value and type of salts in solution.The adsorption of heavy metalions and methylene blue(MB)by grafted polymer was also studied in this work.Some of resultant graft polymers adsorb heavy metal and methylene quickly,the resultant polymer for the polypropylene non-woven fabrics grafted with acrylic acid on its backbone have the best effect in adsorption of Cu²⁺and Pb²⁺,the maximum adsorbing capacity is 99.6mg(Cu²⁺)/g and 343.8mg(Pb²⁺)/g,respectively.The polypropylene non-woven fabric grafted with AA/AM mixture have the best adsorbing effect of MB,the maximum adsorbing capacity is 1185mg(MB)/g,the adsorption speed rate followed the laws of the second order kinetics model of Ho,apparent activation energy of adsorption is 40.24KJ/mol,the isothermal adsorption followed the isothermal adsorption equations of langmuir,the adsorption process was an endothermic chemisorption.