Praparation Of Graphene Oxide-Assisited Dispersion Of Attapulgite Nanocomposites And Its Application In Polymer Modification

As natural one-dimensional nanomaterial, attapulgite (ATT) is abundant and low cost, which promote it to be a great potential reinforcement for polymers. However, attapulgite possesses poor compatibility with polymers and it tends to aggregate when added into the matrix. In recent years, multidimensional nanocomposites prepared from different dimensional nanomaterials are hot research topics. Benefited from various dimensional nanomaterials possessing different agglomerate ways, preparation of nanocomposites from different dimensional nanomaterials to form a multidimensional structure might be useful for suppressing the agglomeration of nanomaterials in polymer matrix. Meanwhile, such nanomaterials possess advantages of both kinds of materials. Herein, taking two-dimensional graphene oxide as a carrier, one-dimensional attapulgite as the receptor, we prepared a series of multidimensional nanocomposites. The morphologies, structure and performance of the obtained nanocomposites were fully studied. And then they were employed to reinforce different polymers. The main contents of this research are as follows:1. Silane coupling agent of KH550 was used to modify attapulgite (ATT-KH550). We take two-dimensional GO as nanocarrier, graphene oxide-assisited dispersion of attapulgite (GO-ATT) was prepared in aqueous solution through electrostatic assembly. By adjusting the ratio of GO and ATT-KH550, GO-ATT reinforcements with different constituents of ATT were obtained. The morphology, structure and properties of GO-ATT were studied. The results showed that ATT was uniformly attached on GO nanoplatelets, and the agglomeration has been obviously reduced. No new defects were generated on GO nanoplatelets during the assembling process, and the crystal structures of GO and ATT have not changed as well. With the higher ATT content in GO-ATT, the interlamellar spacing was gradually increasing and the thermal stability was better.2. Polypropylene (PP) was selected as polymer matrix, GO-ATT(1:9) was as reinforcing filler. PP/GO-ATT with different filler contents of GO-ATT were prepared by melt blending method. The studies showed that the introduction of GO improved the melt processability of PP. The agglomeration of ATT has been obviously reduced and its reinforcement effect for PP was enhanced. When the amount of GO-ATT was 2wt%, the mechanical properties of PP composites were the best, and the tensile modulus, Young’s modulus and storage modulus of which were improved by 53.5%, 143.8% and 37.3%, respectively. Due to the thermal stability of GO-ATT was inferior to ATT, the increase of thermal decomposition temperature of PP cause by GO-ATT was not good as ATT.3. Polyvinyl alcohol (PVA) was selected as polymer matrix, GO-ATT with different constituents were as reinforcing filler. PVA/GO-ATT composites were prepared by solution blending method. Meanwhile, PVA/GO and PVA/ATT were prepared for comparison. The experiments showed that ATT was homogeneous dispersed in PVA by the addition of GO. GO-ATT fillers exhibited a higher enhancement than GO or ATT, which exhibiting synergistic effects of GO and ATT. When the ratio of GO and ATT in GO-ATT was 1:9, the optimum ratio was reached, the mechanical properties and thermal stability of PVA composites were the best, and the storage modulus, tensile modulus and Young’s modulus of which were increased by 83.6%,41.4% and 117.4%, respectively. The thermal decomposition temperature of PVA were improved by 103℃, even better than the modify effect of ATT.4. Polystyrene (PS) was selected as polymer matrix, different constituents of GO-ATT were as reinforcing filler. PS/GO-ATT with 1wt% were prepared by solution blending method. The studies showed that the agglomeration of ATT has been obviously reduced and its reinforcement effect for PS was enhanced. The mechanical properties of PS composites modified by GO-ATT 1:9 were the best, which storage modulus was increased by 75.4%. The glass transition temperature of PS was significantly different from that of modified by ATT, and there was no significant change in the glass transition temperature modified by GO-ATT. When introducing GO-ATT 2:8, the thermal stability of PS composites were the best, GO played an excellent barrier effect.