Failure Mechanism Of Antifogging Greenhouse Film And The Synthesis And Properties Of Polyoxyethylene Graft Polymeric Surfacant

This thesis included two parts: 1) The failure mechanism of antifogging greenhouse films, and 2) the synthesis and properties of polymeric surfactants with PEO grafts. These two parts were independent but have some relationship.In the first part, the relationship between the temperature and the antifogging durability of different antifogging greenhouse films including PE and PVC films, and the diffusion of antifogging agent (GF-1) in the blank PE film were investigated. By using SEM, IR and UV techniques, the changes of the films within and beyond antifogging durability were studied. The experimental results indicate that to all of the films the antifogging durability decreases with the increase of the temperature. Along with the loss of the antifogging agents on surface, what determines the antifogging property of greenhouse films is the supply of inside antifogging agents. The PE and PVC films perform fogging resistance when the apparent concentration of the antifogging agent on film surface reaches 2.15mg/mm3 and 2.84mg/mm3, respectively.The second part mainly relates to the graft polymerization of Polyoxyethylene (PEO) macromers with VAc, AA, and St respectively and the surface property of the graft copolymers. Then we can obtain the methods for polymeric surfactants with excellent surface activity.Three types of copolymers with PEO grafts, synthesized in heat or photo polymerization systems, were purified and then characterized by GPC, IR, 1H-NMR, XPS, SEM, TEM, AFM etc. We have studied their surface activity by means of thecontacting angle against water, emulsion volume and surface force of aqueous solution. We also take many elements into account, such as monomer ratios of PEO to VAc ( or St, AA), kinds of monomers(VAc,St,AA), numbers of EO units in the PEO chain(OP-10, Np-25, NP-40, NP-50), and types of PEO ( PEO, PEG ).Especially, the surface morphology of the graft copolymer films was investigated by the electronic microscope technology. The results show that the graft copolymers do have some surface activity. Using the THF as solvent to form the copolymer film, we found that with the increase of the content of PEO, the length of the PEO side chain and the concentration of solution to form the films, the Contact Angle of water of the copolymer films decreased. It is due to the micelle of graft copolymer was formed in the THF solution.The effect of different solvents to the Contact Angle of water of the copolymer films was studied too. We found that the copolymer exist with different aggregation in different solvent. The micelle was formed in the THF solution and when the toluene as solvent, the reverse micelle was formed. As a result, the Contact Angle of water of the films made from toluene is 90 degree, the same value as that of the pure PS film.