Synthesis and Characterization of Methacrylate Based Copolymers

Random copolymers of poly(ethylene glycol methacrylate) (PEGM), and diethyl amino ethyl methacrylate (DEAEM) were synthesized at low, and high conversions by photoinitiation. Crosslinked poly(PEGM-co-DEAEM) samples were obtained, and characterized by FTIR, SEM, DSC, TGA, and elemental analyses. Swelling behavior of the copolymers revealed that the copolymers acted as superabsorbent hydrogels. The monomer reactivity ratios were calculated using Fineman Ross, Extended Kelen Tüdøs, and Mayo Lewis methods that gave r1(PEGM)=0.90, r2(DEAEM)=0.14 at low conversions. At high conversions r1 and r2 values were calculated as 1.01 and 0.40, respectively. Adsorption isotherms of methyl orange(MO) onto hydrogels were studied using Langmuir, Freundlich, and Temkin models. The experimental data fitted well with the Langmuir equation. The maximum adsorption capacity for MO was 212.7 mg g-1 at pH=3. The adsorption data gave best fit with the pseudo-second order kinetic model. Thermodynamic evaluation showed spontaneous nature for MO adsorption onto poly(PEGM-coDEAEM ) hydrogels. Poly(2-hydroxyethyl methacrylate ) was grafted onto poly(vinyl cinnamate) by photoinitiation using benzophenone (Ph2CO) as initiator, at 360 nm wavelength, and at a total power of 7670 µW.cm-2 . The grafting process was optimized by changing the concentration of HEMA, Ph2CO, chemical crosslinker ethylene glycol dimethacrylate (EGDMA), and UV irradiation time. The polyVCi-graft-polyHEMA films obtained were characterized by FTIR and SEM. The contact angle measurments revealed enhancement of wettability of the polyVCi backbone via the grafting with polyHEMA. TGA analysis confirmed thermal stablility of the films. Swelling behaviors of films were examined in both water and ethanol. Successful photo-encapsulation of flurbiprofen into the film matrixes was confirmed. The PolyVCi-graft-PolyHEMA films proved to be suitable release matrixes for flurbiprofen demonstrating pulsatile release behavior. Zero-order model fitted the flurbiprofen release mechanism. This mechanism was ensured through its RitgerPeppas “n” value (1.00 to 1.41), which indicates super case II release kinetics.