The study is aimed at preparing poly vinyl alcohol (PVA) hydrogel by physical techniques using freeze/thaw method and by chemical method via the addition of cross linking agents, such as Glutaraldehyde (GLT) in different percentages of (1%) and (3%) and boric acide (BA) with percentage of (o.5%) . we prepared of poly vinyl alcohol and Chitosamine chloride (CsmCl) with different weight ratios . These specimens are prepared in the shape of films .
Studies are made on swelling behavior for all prepared samples in different media of PH (neutral , acidic and alkaline) , using Fourier Transform Infra Red (FTIR) in order to investigate the linking between (PVA) and cross linking agents and the blends .
From the test result , it is found that swelling percentage depends on cross linking degree , whether it is physical or chemical ; all sample possess high swelling percentage during the first 5 hours then settle at discrete percentage , which are attributed to disentanglement of chains that are not involved in cross linking . The freeze/thaw process leads to physical cross linking of polymer chains.
Results have proved that samples containing (1%GLT) and (0.5% BA) undergo increase in their water absorption after freezing and thawing , while samples containing (3%GLT) have undergone decrease in percentage . As to swelling ration in alkaline medium increase , while the (PVA) sample retained their swelling percentage in the acidic media , as in distilled water for samples containing (GLT) . As for swelling behavior of blends , the swelling percentage is found to increase with increase of (PVA) percentage , which may be attributed to increase water absorbing (OH) in the blends .
The FTIR spectra for all samples before and after blending and treatment are found to appear and disappear besides band shift at different location; this is attributed to changes in conformation. The spectral intensity decreases with increasing (CsmCl) percentage explained in view of when two polymers or more are blended , changes occur in the characteristic spectra as a result of reflection in the blend that are prepared by physical mixing and chemical reaction