Synthesis And Thermal Degradation Behaviors Of Polyacrylate With Easy Degradation And Low Residual Rate

Polyacrylate is synthesized by homopolymerization or copolymerization of acrylates. Polyacrylate, which has low cost, no pollution and wide selectivity of monomers, is mainly used in the pressure-sensitive adhesive, sealant for building, textile finishing and packaging and so on. In recent years, with the development of welding technology in aeronautics and astronautics, it is important to develop environmentally friendly adhesive with easy degradation and low residual rate. Therefore, in this work, a series of copolymers were prepared by emulsion polymerization of butyl acrylate(BA), 2-ethylhexyl acrylate(2-EHA), alpha-methyl styrene(α-MeSt) and methyl methacrylate(MMA), and then studied the structures of the production and their thermal behaviors. The primary contents are as follows:1. A series of copolymers were prepared. Moreover, the polyacrylate copolymers were characterized by FTIR and 1H-NMR. The glass-transition temperature of the polyacrylate copolymers was tested by DSC.2. The decomposing enthalpy and the decomposing temperature of the copolymers were characterized by DSC. It can be found that the thermal degradation of the poly(acrylate/a-MeSt) copolymers gave off heat around 177 ℃. And the exotherm was proportional to the content of a-MeSt in the copolymers. However, for the poly(acrylate/MMA) copolymers, there was no heat around 177 ℃. Additional, GPC result indicated that the molecular weight of the poly (acry late/a-MeSt) copolymers became smaller and some small chain segments were generated because of bond breaking. The GPC and DSC measurements showed that bond breaking of the poly(acrylate/a-MeSt) copolymers occurred at the a-MeSt units at a relatively low temperature compared with neat polyacrylates.3. By using TGA, the influences of the kinds of monomers and the heating rates on the degradation residual rate were studied which indicated that the degradation residual rate of a-MeSt-20 was lowest at the heating rate of 5℃-min-1.4. Non isothermal degradation kinetics of the acrylate copolymers was investigated by TGA. Kissinger method and Flynn-Wall-Ozawa method were applied to calculate the kinetic parameters of the copolymers. Meanwhile, the relationship between the thermal degradation activation energy and the thermal behaviors was studied for the different systems of copolymers.5. The adhesive properties of the copolymers were characterized which showed a good property for adhesive.