| In this dissertation, studies are mainly focused on the copolymerization, vulcanization and the modification of acrylate rubber prepared by emulsion copolymerization and continuous solution polymerization, including the effect of initiator system on the copolymerization rate, influence of the reactive conditions on the gel content; influence of main monomer composition and off volatile condition on raw rubber performance; the optimization of acrylic rubber vulcanization process, including the influence of cure agent and carbon content on vulcanized rubber properties; and also the modification of acrylic rubber with the addition of grafted silica, including the additive dispersion and mechanical properties of the rubber prepared. Furthermore, the systems of nylon6modified with different concentration of acrylic rubber are also studied in the paper, including the thermal dynamics, crystallization behaviors and mechanical properties. The main contents of studies are shown as the following aspects:1. Emulsion copolymerization of acrylate rubber:The epoxy ACM were prepared by emulsion copolymerization of BA and GMA. The reaction conditions and their effect on the gel content of product are discussed by investigating the influence of initiator system on copolymerization rate and comparing of a series of gel contents and epoxy-opening ratios acquired by different reaction parameters. The results show that the gel content can be less than2.9%, reach the level of foreigh similar product, by the feeding of EA as secondary monomer in a "starve" state in the organic redox complex initiating system, temperature of25-30℃, because the intermolecular transferring of BA and ring-opening of epoxy groups of GMA can be restrained successfully.2. Continuous solution polymerization of acrylate rubber:In order to obtain the influences of main composition monomer and off volatile condition on raw rubber performance, ACM were prepared by continuous solution polymerization with the main composition monomer of BA and EA, respectively. The molecular weights and distributions obtained are almost the same with different aggregate of main composition monomers, while the glass transition temperature (Tg) of the product varies obviously. The variety of the off-volatile temperature and the revolutions speed results in changes of glass transition temperature (Tg) and molecular weight. The higher temperature off volatile are together with increased molecular weight and widen distribution as well higher glass transition temperature(Tg), while, higher off-volatile revolutions speed leads to lower molecular weight and also wider distribution, as the glass transition temperature(Tg) does not change. The variety of the off-volatile temperature and the revolutions speed results in the droping off-volatile components. 3. Optimization of acrylic rubber cure process parameter and technique formula: Comparison performed among a series of vulcanization and additive systems designed based on the vulcanization and filling strengthen mechanism. From the experiments results it shows that the vulcanization agent and carbon black volume added are related to the acrylic rubber performance as expected, the more vulcanization agent and carbon black added, the higher Shore hardness and the better oil resistance property obtained, while the tensile strength first increases after declining. The break elongation rate keeps droping. The effect of vulcanization agent and accelerant show a cooperation action and the volume of sulfur shows a critical value of0.5shares. From the experimental results, it is shown that the best usage of vulcanization is2%, carbon black volume is50%.4. The effect of grafted silica reinforcing fillers on the performance of acrylic rubber: Experiments of reinforcing the acrylic rubber by the grafted silica with four kinds of different surface modification performed in order to get the information of the effect of the additive on the acrylic rubber mechanical properties. The result indicates that the dispersion property of the GMA grafted silica modified with dispersant and coupling agent is better and more homogeneous, in which there is some chemical reaction between the GMA grafted silica and the rubber substrate, and the particles are covered by the rubber substrate perfectly; in the meantime, the mechanical properties of the grafted silica filled acrylic rubber is best among the four different modified silica-filled rubbers. When the amount of silica is40%, the tensile strength reaches10.87MPa.5. The thermal behaviors of nylon6/acrylate rubber (ACM)) blends:Nylon6/acrylate rubber (ACM)) blends are prepared by melt processing and the thermal behaviors have been investigated by differential scanning calorimetry (DSC), The DSC result indicates that the melting temperature, Tm, and the crystallization temperature, Tc, of blends decrease slightly with the increasing of ACM concentration in the blends. The crystallization behavior of the blends studied by wide angle X-ray diffraction (WAXD), and it is revealed that a y→a crystal phase transformation occurs upon addition of ACM into the nylon6, and the crystallinity and crystal size decrease with addition of more ACM into the nylon6. Furthermore, morphologies of nylon6and nylon6/ACM blends are also observed by Polarizing microscope (PLM). It was found that crystal size of nylon6/ACM becomes smaller and crystals of nylon6/ACM are not so perfect any more while the content of ACM increases in the blends. Mechanical experiments show that the notched impact strength of Nylon6/acrylate rubber (ACM)) blends are also enhanced by the addition of modified rubber plastic. |
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