Study On Pulping Lime Mud/HDPE Blending Composites

Large amount of lime mud can be brought in the state of alkali recovery of chemical pulping. So far, the principal treatment for lime mud is burying in both domestic and foreign countries, which brings heavy dealing burden to papermaking mills. Thus, it is urgent to explore efficient application of technology for pulping lime mud. The high density polyethylene is easy to shape, and inorganic reinforcement compatibility, so the resin materials based on high density polyethylene has developed rapidly and has been widely used. This is of great significance for the maintenance of ecological balance and protecting forest resources.In this paper, pulping lime mud/HDPE blending composites were prepared with modified pulping lime mud as filler and HDPE as matrix. The effects of the injection parameters on the mechanical properties of composites were discussed. The best injection molding process conditions were:the injection temperature of230℃; the first section injection pressure is40bar,the second section injection pressure is30bar; the first injection rate50%,the second injection rate40%, and the screw speed was35%.The papermaking lime mud was modified with different kinds of surface agents, and the effects of surface modification agents on papermaking lime mud-HDPE composites were investigated. The results showed that the mechanics performance of composites first increased and then decreased with the increasing in the amount of modifier. After modification with silane, the mechanical properties of composite materials achieved to the best. By examining the effects of modifiers on the rheological properties of the composites, it was found that the silane surface modifier can improve the rheological properties of composite materials, and ultimately improve the processing properties of the composites.The effects of the filling of papermaking lime mud on the performance of composites were investigated. The results showed that the density of the composite materials was rising with the increase of the amount of papermaking lime mud, but the other mechanical properties of the composite materials first rose and then dropped with the increase of the amount of papermaking lime mud. When the filling volume of the papermaking lime mud was20phr, the mechanical properties of composite materials achieved to the best, and the rheological properties of the composites were also very good, which were significantly better than that of the pure HDPE resin. So the best filling volume of the papermaking lime mud was20phr.Finally, the composite mechanism of the papermaking lime mud and the HDPE was studied by using the SEM、IR and TG. First of all, the IR spectrogram of the lime mud with and without modified has been analyzed. It was found that the group of C-H bond absorption peak at around2960-2850cm-1appeared after modification with aluminate, and the group of Si-O bond absorption peak at around770cm-1appeared after modification with silane. According to the thermal weight loss curves of the composites, the maximum temperature of thermal decomposition of the composites significantly higher than that of the pure HDPE, which indicated that the thermal stability of the composite materials has been improved to a certain extent after adding the modified lime mud...