失水处理对Poly(AAc-co-AM)/Fe^3+配位水凝胶的结构及力学性能影响

Effect of Water Dehydration Treatment on the Structure and Mechanical Properties of Poly(AAc-co-AM)/Fe^3+ Coordination Hydrogels

制备了含有不同丙烯酸(AAc)/丙烯酰胺(AM)摩尔比的Poly(AAc-co-AM)水凝胶,将其浸泡在FeCl3溶液再经过在去离子水中的平衡溶胀后得到初始的Poly(AAc-co-AM)/Fe^3+(AY-Fe)配位水凝胶,再失水获得含水量约40%的Poly(AAc-co-AM)/Fe^3+(Ad-Fe)配位水凝胶。测定并比较了失水前后的不同配位水凝胶的力学性能,AY-Fe水凝胶的断裂应变为500%~800%,Ad-Fe水凝胶的断裂应变为550%~1700%,AY-Fe水凝胶的断裂强度为0.29~6 MPa,Ad-Fe水凝胶的断裂强度为2.59~14 MPa。用元素电子扫描电镜(SEM-EDS)面分析得到AY-Fe, Ad-1-Fe配位水凝胶中的Fe元素分布均比较均匀,失水后,Fe元素分布密度的提高有利于Fe^3+与COO^-间的配位;用红外光谱和紫外光谱揭示了配位水凝胶失水前后的键合作用变化。

Poly(AAc-co-AM)hydrogels containing different mole ratios of acrylic acid(AAc)/acrylamide(AM)were prepared by free radical polymerization.The initial poly(AAc-co-AM)/Fe3+coordination hydrogels were obtained by soaking them in FeCl3 solution and then after equilibrium swelling in deionized water,named as AY-x-Fe.The poly(AAc-co-AM)/Fe3+coordination hydrogels with the water content of about 40%were obtained by air dried dehydration,named as Ad-x-Fe.The mechanical properties of AY-x-Fe,Adx-Fe hydrogels were characterized by INSTRON-5567 electronic stretcher.The results show that the mechanical properties of coordination hydrogels are significantly improved after dehydration.The fracture strain of AY-Fe and Ad-Fe hydrogel is 500%~800%and 550%~1700%,respectively.The fracture stress of AYFe and Ad-Fe hydrogel is 0.29~6 MPa,2.59~14 MPa respectively.The cross-section network structure and Fe element of AY-1-Fe,Ad-1-Fe hydrogels were characterized by the combination of scanning electron microscope(SEM)and elemental energy spectrometer(EDS).The results demonstrate that the density of Fe element in the Ad-1-Fe matrix is larger than that of AY-1-Fe,thus facilitating the coordination between Fe3+and carboxyl groups.The coordination interactions and hydrogen bonding of the AY-1-Fe,Ad-1-Fe hydrogel were tested by FT-IR and UV.