The Latex Film With Microphase Structure Was Prepared Based On The Click Chemical Reaction Of The Colloidal Interface

The pigment-dyeing binders are expected to have the mechanical properties of high tensilestrength and low modulus, contributing to the soft handling and high crockfastness of the dyedfabrics. It has been revealed that microphase separation structure formed in the copolymers couldendow the copolymer with target tensile properties mentioned above, especially when the hardblock domains dispersed in the soft block matrix. However, it is restrained by the limitingmobility of the hard block at the chain end that microphase structure could hardly be detected inlatex film.Aiming at solving the problem, during latex formation process, click chemistry wasinitiated purposely at the interface of the latex with microphase morphology. And, latex film withclear microphase separation structures acquired finally. The followings were systematicallyinvestigated.BESt (1-((but-3-enyloxy)methyl)-4-vinylbenzene) with two unsymmetric vinylic groupswere prepared. Then, an amphiphilic RAFT agent with side chain ene groups was produced via atwo-step solution polymerization of AA and St/BESt, where the ene groups located between thehydrophobic and hydrophilic block.The kinetic of styrene emulsion polymerization mediated by the RAFT agent with enegroup was investigated. It was found thatM ns grew linearly with conversion, and PDIremained below1.4before80%conversion, demonstrating the “living” characters ofpolymerization. The particle size changed with the HLB value (Hydrophile-Lipophile BalanceNumber) of the RAFT agent. Ene groups were proved to distribute at the surface of the particles,and could engage in a further thiol-ene click chemistry. When RAFT agents with side-chainvinylic groups were used,M ns of the resulted polymers deviated positively from the theoreticalvalues, and agreed well with twice of the theoretical ones, which were found to be related to thenano-heterogeneous nature of the emulsion polymerization. In the case of the RAFT agents withthree ene groups per molecule, as the polymerization proceeded, reaction of the vinylic groupscould become more and more important at higher conversion. The yield of branched polymerscaused the steep increase of experimentalM ns and PDIs during high-conversion (>90%) period.Finally, PSt-b-PBA particles with microphase morphologies were prepared. Being of acharacteristic of interfacial distribution, ene groups could further react with the post-added thiolsunder UV radiation, and latex film with microphase structures were prepared. Those factors (e.g.,volume fraction of latex, UV radiation times) that might affect the tensile properties of the filmwere studied. In comparison to that of the triblock copolymer solvent casting films, themechanical properties of the latex film were much inferior, which were likely caused by theunexpected cross-linking reaction during the preparation of PBA block.