| Interpenetrating polymer networks (IPNs) are relatively novel types of polymer alloys consisting of two or more crosslinked polymers held together by permanent entanglements with only accidental covalent bonds between the polymers. There is growing interesting in these fields since it is one of the most important techniques for modification of polymers. IPNs possess several interesting characteristics in comparison to normal polyblend. Formation of IPNs is only way of intimately combining crosslinked polymers; the resulting mixture exhibits (at worst) only limited phase separation. Normal blending or mixing of polymers results in a multi-phase morphology due to the well known thermodynamics incompatibility of polymers. However, if mixing is achieved simultaneously with crosslinking, phase separation may be kinetically controlled by permanent interlocking of entangled chain. Polyacrylate (PA) and fluoro-polymer (FP) latexes have been widely used for coating industry as the result that PA latex has good adhesive force to substrate material, while FP latex has good ageing resistance and anti-fouling. Therefore novel FP/PA hybrid latexes can be designed such that they can compensate each other for unfavourable properties of the other component. Recently, many research groups have reported that fluorine-containing acrylic resin latexes were achieved by copolymerization of acrylic monomers along with fluorine-monomers. However, the method that FP/PA hybrid latexes were prepared by latex IPN (LIPN) technique is still unexplored. In this paper, the methods of preparation and characterization, which employed IPNs techniques, were introduced in details. Also three FP/PA hybrid latex IPNs (FR301/PA LIPN, FR463/PA LIPN, FKM/PA LIPN) were synthesized. The results illustrate that the properties of hybrid latexes made by LIPNs technique can be extensively enhanced on water resistance, solvent resistance, anti-fouling as well as compatibility of the blend. It is believed that the study will be useful to achieve desired broad applications in coating industry and helpful to understand the polymerization mechanism of these hybrid latexes.1. Synthesis of FP/PA LIPN Hybrid LatexesIn this paper, FP/PA hybrid latexes were synthesized by using the amount of fluoro-polymer latex swollen with acrylic monomers as the seed, then the remainder monomer blends were introduced to polymerize. To obtain excellent storage stability andcompatibility of hybrid latexes, carbon-fluorine and carbon-hydrogen surfactants, along with protective colloids were added to emulsion polymerization. The results demonstrate that these hybrid latexes have good compatibility and stability. Furthermore hydrophilic or hydrophobic crosslinkers can be introduced in the reaction system as the third component so that it can further reinforce synergistic action and entanglement between polymers. 2. Morphology of FKM/PA LIPN Hybrid Latexes1. TEM pictures have been obviously noted that the compatibility between fluoro-polymer and PA polymer has been enhanced greatly since the interpenetrating network structure prevailed to the FKM/PA hybrid latexes, which made the structure and morphology of these hybrid latexes finer and more uniform. 2. Where FKM content is less than 12% in FKM/PA hybrid latexes, there is only one peak of Tg in DMA plots of FKM/PA hybrid latexes, which indicates that FKM and PA have good compatibility. However, where FKM content is greater than 20% in FKM/PA hybrid latexes, there appear two peaks of Tg in DMA plots of FKM/PA hybrid latexes, which imply that there is phase separation between FKM and PA polymers.3. X-ray patterns show that non-crystalline structure dominates in FKM/PA hybrid latexes, which reinforce the idea that the formation of FKM/PA LIPNs could decrease the crystallinity of FKM polymer greatly.4. FT-IR imaging shows that main groups of FKM/PA LIPN distribute uniformly on the film surface and no segregation happens.5. The particle size & distribution of FKM/PA hybrid latexes varies the decrease with increas... |
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