Study On The Preparation And Properties Of PAA/Cellulose Composite Hydrogels

Bacterial cellulose (BC) or microcrystalline cellulose (MCC) liquor was added to polyacrylic acid hydrogels to produce PAA/cellulose composite hydrogels. The composite hydrogel composition was determined by testing properties such as water absorption performance, water retention properties, metal ion adsorption performance, thermal performance, and dynamic mechanical properties. In addition, the microstructure, chemical composition and structure of the hydrogels were characterized. The experimental results showed that the composite hydrogels performance, including water absorption, water retention, and thermal performance, increased obviously after adding the BC or MCC, and the best concentration of the BC (or MCC) was 0.6 wt%. See from IR test after adding cellulose, hydroxy peak strength, peak groups were broadly similar. We can conclude that adding cellulose can not introduce new characteristic peak. Results can be found by scanning electron microscopy, the cross-section porosity increased obviously after adding cellulose, but also more uniform,which made the composite hydrogels have larger storage space.The different ratio of acrylamide, acrylic acid monomer and cellulose (BC, MCC) orthogonal experiment was carried out to produce P(AA-co-AM)/cellulose composite hydrogels. Through a series of experimental test results show that under the condition of the AM/AA were 60 wt% and 70 wt%, the highest water imbibition of composite hydrogels, and the strong ability of water retention. When BC content was 0.4 wt%, MCC content was 0.4 wt%and 0.6 wt%, the absorbent, water retention, swelling performance of the compound hydrogels was the best. After adding cellulose, the energy storage modulus of composite hydrogels was greatly increased, and a higher degree of crystallinity, mechanical properties had universal enhancement. At the same time, the composite hydrogels had higher melting point, heat resistant performance was improved. IR test showed that acrylamide and acrylic acid did happen copolymerization reaction, the addition of cellulose also won’t appear new characteristic peak. SEM test results showed that after adding the BC and MCC, composite hydrogels have more micro pore structure, pore arranged densely and homogeneous.Test the adsorption of metal ions of the hydrogels in best perfomance. This paper selected the heavy metal ions for copper ions. The results show that the composite hydrogels have strong ability of adsorption of heavy metal ions, especially P(AA-co-AM) composite hydrogel, its adsorption ability was better. Cellulose (BC or MCC) added in the PAA has little influence on the performance of adsorption, also can absorb most of the copper ions. After adding cellulose (BC, MCC) in P(AA-co-AM), adsorption ability increased obviously, probably due to the microporous structure of the cellulose was easier to absorb water and the ions in the water, and because of acrylamide contains a large number of amide groups, etc., these will be conducive to the adsorption of copper ion and other heavy metal ions.