Study On Preparation Of Nanocellulose/PNIPAm Composite Hydrogels And PNIPAm-based Composite Nanogels With Ag Nanoparticels

In order to overcome the problem of bamboo long-acting mildew,the Ag nanoparticles was implanted in PNIPAm-based nanogels to obtain temperature-sensitive nanogels with antibacterial activity,then used to treat bamboo and bamboo products,and finily marealized act-lasting mildewproof via thermo-sensitive properties of the composite nanogels.In the paper,the main work and conclusion are listed as follows:(1)A series of semi-IPN hydrogels,which were made of N-isopropylacrylamide(NIPAm)and N,N-methylene bisacrylamide(MBA),with TEMPO-oxidized cellulose nanofibers(TO-NFC)were prepared via free radical solution polymerization,and its swelling and mechanical properties were investigated.The results showed that the introduced TO-NFC significantly improves the swelling and compressive properties of PNIPAM hydrogel,especially with high content of TO-NFC,the composite hydrogels' swelling ratio was up to 42 g/g which was twe times than that of pure PNIPAm,and the compression strength can reach 61.53 MPa as five big as the pure one.(2)Using NIPAm and MBA as the main resources,a series of nanogels were synthesized by free radical solution polymerization.Then effects of the component in preparation on the resulted nanogel size were investigated.And it was found that the resultant nanogels exhibited homogeneously dispersion and uniform particle size around 28.6nm when the contents of the monomer NIPAm,cross-linking agent MBA,Initiator KPS and the catalyst TEMED was 0.75mg/mL,.0.255 mg/mL,0.300mg/mL and 0.563 mg/mL,respactivity.(3)With NIPAm and acrylic acid(AAc)as raw material,MBA as cross-linking agent and silver nitrate(AgNO3)as the source of silver,twee kinds of the composite nanogel with Ag nanoparticles,namely Ag/PNIPAm nanogel and Ag/P(NIPAm-co-AAc)nanogel was in situ synthesized through free radical solution polymerization.And then the morphology and the particle size of the obtained nanogels were investigated.The results showed that the twee nanogels exhibited uniform nanoparticles with ~50nm diameter and the Ag content in P(NIPAm-co-AAc)nanogel is much more than that in PNIPAm nanogel.The Ag/P(NIPAm-co-AAc)nanogel exhibited the core-shell structures with ~10nm Ag nanoparticels.(4)The findings of this study is of very important significance to expand the application of PNIPAm-based nanogel and to realized bamboo long-acting mildewproof.