基于“滑轮”效应设计构筑聚合物微球及其在孔隙中的受力形变行为研究

A novel micro or nano level microsphere crosslinked by slide-ring polyrotaxane molecule will be designed and synthesized in this subject. We expect the “slide-ring” effect will provide better deformation property. The vinyl cyclodextrin(CD) is synthesized and react with modified polyvinyl alcohol (PVA) to produce poly(pseudo)rotaxanes. Next, the poly(pseudo)rotaxanes are blocked by larger molecule to form polymerizable polyrotaxane crosslinker (PPC).The acrylamide and other modified monomer are copolymerized with PPC to prepare the micro or nano level microsphere based on the slide-ring effect. The properties such as swelling, stability and size distribution are investigated. The deformation in porous media and mechanical parameter (such as Poisson ratio and Young's modulus) are got by the study of capillary micromechanics and atomic force microscope technology. The basic principle of the effect of “slide-ring” cross linking point on deformation property and mechanical property is tried to find out. The plugging-move property of microspheres in porous media and the matching relationship between size and pore throat are try to ascertain in the combination with the deformation property. The successful implementation of the subject will provide new ideas for introducing slide-ring cross-link points into micro/nanoscale spherical particle material. The related studies can further enrich the basic mechanical theory about deformation of microsphere in pore-scale space. The results of the study will lay a foundation for the development and application of functional microsphere used in deep profile modification and flooding. So the study has great theoretic and engineering application values.

本课题拟设计构筑一类结构新颖的滑动轮作为交联点的微纳米级微球，以期“滑轮”效应赋予微球更好的形变能力。首先合成出乙烯基环糊精，与改性聚乙二醇形成准聚轮烷，再由大体积分子封端形成可聚合的聚轮烷交联剂，将聚轮烷交联剂与丙烯酰胺及改性单体悬浮或者微乳液聚合制备出滑动轮交联微球。明确该类微球的溶胀性、稳定性、粒径分布等基本性质。基于锥形毛细管微观力学法结合原子力显微技术，探明该类微球的在孔隙尺度空间中的形变行为及杨氏模量、柏松比等力学性质参数，阐明“滑轮”交联点如何控制其力学性质及形变能力的基本原理。结合其形变能力，探究新型微球在孔隙介质中的封堵-运移性质及与孔隙尺寸的匹配普适性规律。该项目的成功实施将为滑动轮交联技术引入到微纳米尺度球型颗粒材料提供思路，进一步丰富在孔喉尺度空间中研究微球形变的基础力学理论，同时也为研制适合深部调驱的功能性微球及其应用奠定技术基础，具有重要的理论意义和应用价值。

针对目前微球、微凝胶等凝胶类调驱剂由于化学交联点分布不均匀所导致的脆性大、形变能力弱等问题，设计出聚轮烷交联剂，由于交联点可沿聚合物链滑动，产生的“滑动效应”可使得凝胶所受外力均匀分散到整个网络，从而一定程度解决脆性及形变问题。首先基于环糊精制备出几类聚轮烷交联剂，具有代表性的有以下两类，对于α-环糊精，设计构筑了衣康酸酐基α-环糊精(IAH-(α-CD))型交联剂，将α-CD贯穿于PEG链上形成α-环糊精聚乙二醇((α-CD)-PEG)型准聚轮烷，使用衣康酸酐(IAH)对(α-CD)-PEG型准聚轮烷的端基及环糊精同时进行改性，制备出轮烷交联剂。对于β-环糊精，设计构筑了聚醚胺β-环糊精(PEA-(β-CD))型交联剂。分别使用IAH-(α-CD)型交联剂、PEA-(β-CD)型交联剂和传统交联剂在相同条件下与水溶性单体丙烯酰胺(AM)共聚合成凝胶颗粒，研究了凝胶在不同温度、不同矿化度条件下的溶胀行为，研究发现IAH-(α-CD)型交联剂制备的凝胶颗粒适用于40℃以下的油藏条件，PEA-(β-CD)型交联剂制备凝胶颗粒适用于60℃以下的油藏条件，60℃以上的油藏条件，两种聚轮烷交联剂制备的凝胶颗粒均不适用。通过锥形毛细管微观力学法对比测定3种凝胶颗粒的力学性质，并计算压缩弹性模量、剪切模量、杨氏模量等力学参数，IAH-(α-CD)型交联剂制备的凝胶颗粒更容易发生形变，压缩弹性模量为0.01、剪切模量为0.03、杨氏模量为0.05。分别由传统交联剂及聚轮烷交联剂制备出凝胶分散体，研究了凝胶分散体在孔隙介质中的运移行为，发现聚轮烷交联剂制备的凝胶分散体的注入压力更小，但是残余阻力系数更高，表明其在孔隙介质中更容易运移，同时也更容易在孔隙介质中发生滞留。