With Methyl acetoacetate (MAA) and Neopentyl glycol diacrylate (NPGDA) as raw materials, a linear polymer, Poly (Methyl acetoacetate?Neopentyl glycol diacrylate) (P(MAA?NPGDA)),was prepared via a base?catalyzed Michael addition reaction to extend the molecular chain. The synthesized samples were characterized and analyzed by Fourier transform infrared spectroscopy (FTIR),proton nuclear magnetic resonance spectroscopy （¹H NMR）,differential scanning calorimetry（DSC）,high?performance liquid chromatography （HPLC） and gel permeation chromatography（GPC）. The effects of different catalysts on the relative molecular weight growth, heat release rate, and double bond conversion rate of monomers during the reaction were investigated at various temperatures. Furthermore, by using 1,8?Diazabicyclo[5.4.0]undec?7?ene (DBU) as the catalyst, the impacts of varying reaction temperatures, catalyst concentrations, and the ratio of n(MAA) to n(NPGDA) on the molecular weight growth of linear polymers were examined. Under the tested conditions, in a reaction temperature range of 30-40 ℃ with a DBU mass fraction of 2%, and a MAA?to?NPGDA monomer ratio of 1.00∶1.00, the growth rate of P(MAA?NPGDA) molecular weight was relatively stable, and the polymer ultimately reaches a relatively high relative molecular weight.

In some areas of Xinjiang, the dip angle of coal seams can reach 50 °. Unlike horizontal coal seams, fluids in high dip coal seams are severely affected by gravity, and the pressure propagation law of coalbed methane wells has special characteristics. The optimal drainage and extraction well position needs to be optimized. This article considers the gravity effect of formation water and establishes a pressure propagation model for single-phase drainage in steep coal seam, and verifies the correctness of the model.Then, the water production of fractured wells in the inclined reservoir is calculated under stable seepage conditions, and the optimal drainage well position is optimized. Finally, numerical simulation methods are used to study the pressure propagation laws of single wells and well groups in heterogeneous bounded inclined reservoirs. The results show that in a high dip coal seam with an inclination angle of 45 °, the position where the distance ratio between the drainage well and the upper and lower boundaries is 3 : 1 is the optimal drainage well position; under the constant pressure drainage mode, there is not much difference in the pressure drop amplitude between the downward and upward tilt directions. In the constant speed depressurization and extraction mode, the pressure drop amplitude in the upward tilt direction is much greater than that in the downward tilt direction.