Haoran Zhu,Chuanxian Li,Zongming Xiu,Zhiqiang Zhao,Kai Mu,Hui Dai,Feng Wang,Fei Yang,Bo Yao
In this paper, a novel ethylene-vinyl acetate copolymer (EVA)/amino-functionalized polymethylsilsesquioxane (PAMSQ) composite wax inhibitor (WI) was prepared through melt blending, and the rheological and wax depositing properties of the doped crude oil were studied. The EVA/PAMSQ composite can strongly crystallize with wax molecules and trigger the formation of compact wax flocs, which greatly improve the rheological properties of crude: compared to the pure EVA at the same dosage, the composite can further decrease the gel point and apparent viscosity (25 °C) by 14.6 °C and 92.0%, respectively. The wax deposition can also be inhibited by adding the composite: adding EVA inhibits the mass of the wax deposit at 24 h by 62.3%, and this number is suppressed by 77.9% after adding the EVA/PAMSQ composite, but the wax molecule diffusion is accelerated and the wax content in the wax deposit rises because of the improved crude oil rheological characteristics. Here, we develop the gel structure theory to consider the wax deposition process affected by the WI. Adding the WI contributes little to the wax precipitation temperature but decreases the gel structural strength of the oil a lot, and thus, the oil near the pipe wall can only form the wax deposit with a higher wax content to resist the pipe wall shearing. Therefore, the crude oil added EVA/PAMSQ composite possesses not only the lowest wax deposit rate and the highest aging rate but also the highest wax content in the wax deposit.
To prevent the degradation of wood surfaces by ultraviolet radiation and liquid water, modified polyethylene wax and modified polyethylene wax/oxidized paraffin composite wax were used for the protection of wood surfaces with hot wax treatment. The effects of natural beeswax coating and modified synthetic wax coating on wood surface aging behavior were also studied. Results showed that changes in color, gloss, water uptake, contact angle, micro-morphology, and chemical changes of wood treated with modified synthetic wax hot waxing were less than those of wood treated with natural beeswax hot waxing after long-term aging under ultraviolet (UV) light and water. Among them, the modified polyethylene wax/oxidized paraffin composite wax coating showed the best protective effects on the wood surface, and the composite wax coating reduced the UV penetration and enhanced the UV oxidative degradation resistance. In addition, the synergistic effect of modified polyethylene wax and oxidized paraffin further reduced the water uptake of wood during aging process. This data clearly shows that the modified synthetic wax and composite wax coating can effectively inhibit the photooxidative degradation of wood surface, provide a lasting hydrophobic protection effect on wood, and show long-term photostability.
危险品化学品经营许可证（带存储）