{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,4]],"date-time":"2026-10-04T04:35:12Z","timestamp":1791088512304,"version":"4.1.0"},"reference-count":30,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2023,5,8]],"date-time":"2023-05-08T00:00:00Z","timestamp":1683504000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["52174014"],"award-info":[{"award-number":["52174014"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["2020ZLYS07"],"award-info":[{"award-number":["2020ZLYS07"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Key Research and Development plan of Shandong Province (Academician Team Support Project)","award":["52174014"],"award-info":[{"award-number":["52174014"]}]},{"name":"Key Research and Development plan of Shandong Province (Academician Team Support Project)","award":["2020ZLYS07"],"award-info":[{"award-number":["2020ZLYS07"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gels"],"abstract":"<jats:p>A common problem associated with conventional gel breakers is that they can cause a premature reduction in gel viscosity at high temperatures. To address this, a urea-formaldehyde (UF) resin and sulfamic acid (SA) encapsulated polymer gel breaker was prepared via in situ polymerization with UF as the capsule coat and SA as the capsule core; this breaker was able to withstand temperatures of up to 120\u2013140 \u00b0C. The encapsulated breaker was characterized using scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), and thermogravimetric (TG) analysis. Meanwhile, the dispersing effects of various emulsifiers on the capsule core, and the encapsulation rate and electrical conductivity of the encapsulated breaker were tested. The gel-breaking performance of the encapsulated breaker was evaluated at different temperatures and dose conditions via simulated core experiments. The results confirm the successful encapsulation of SA in UF and also highlight the slow-release properties of the encapsulated breaker. From experimentation, the optimal preparation conditions were determined to be a molar ratio between urea and formaldehyde (nurea:nformaldehyde) of 1:1.8 for the capsule coat, a pH of 8, a temperature of 75 \u00b0C, and the utilization of Span 80\/SDBS as the compound emulsifier; the resulting encapsulated breaker exhibited significantly improved gel-breaking performance (gel breaking delayed for 9 days at 130 \u00b0C). The optimum preparation conditions determined in the study can be used in industrial production, and there are no potential safety and environmental concerns.<\/jats:p>","DOI":"10.3390\/gels9050387","type":"journal-article","created":{"date-parts":[[2023,5,8]],"date-time":"2023-05-08T02:29:22Z","timestamp":1683512962000},"page":"387","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Preparation of Encapsulated Breakers for Polymer Gels and Evaluation of Their Properties"],"prefix":"10.3390","volume":"9","author":[{"given":"Kaihe","family":"Lv","sequence":"first","affiliation":[{"name":"Department of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China"},{"name":"Key Laboratory of Unconventional Oil & Gas, Development Ministry of Education, Qingdao 266580, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Guodong","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China"},{"name":"Key Laboratory of Unconventional Oil & Gas, Development Ministry of Education, Qingdao 266580, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6786-6835","authenticated-orcid":false,"given":"Yingrui","family":"Bai","sequence":"additional","affiliation":[{"name":"Department of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China"},{"name":"Key Laboratory of Unconventional Oil & Gas, Development Ministry of Education, Qingdao 266580, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7678-9536","authenticated-orcid":false,"given":"Jingbin","family":"Yang","sequence":"additional","affiliation":[{"name":"Department of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China"},{"name":"Key Laboratory of Unconventional Oil & Gas, Development Ministry of Education, Qingdao 266580, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,5,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"128244","DOI":"10.1016\/j.colsurfa.2021.128244","article-title":"High temperature resistant polymer gel as lost circulation material for fractured formation during drilling","volume":"637","author":"Bai","year":"2022","journal-title":"Colloids Surf. 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