{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,29]],"date-time":"2026-08-29T15:56:19Z","timestamp":1788018979632,"version":"build-2784847793"},"reference-count":34,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,7,9]],"date-time":"2026-07-09T00:00:00Z","timestamp":1783555200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Shaanxi Key Research and Development Plan","award":["2023-YBGY-052"],"award-info":[{"award-number":["2023-YBGY-052"]}]},{"name":"Key Scientific Research Project of Shaanxi Provincial Department of Education","award":["23JP113"],"award-info":[{"award-number":["23JP113"]}]},{"name":"Xi\u2019an Shiyou University Graduate Student Innovation Fund Project","award":["YCX2612030"],"award-info":[{"award-number":["YCX2612030"]}]},{"award":["YCX2612030"],"award-info":[{"award-number":["YCX2612030"]}],"id":[{"id":"https:\/\/ror.org\/040c7js64","id-type":"ROR","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["52304037"],"award-info":[{"award-number":["52304037"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"award":["52304037"],"award-info":[{"award-number":["52304037"]}],"id":[{"id":"https:\/\/ror.org\/01h0zpd94","id-type":"ROR","asserted-by":"publisher"}]},{"name":"Scientific Research Program funded by Shanxi Provincial Education Department","award":["22JP066"],"award-info":[{"award-number":["22JP066"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Gels"],"abstract":"<jats:p>Reducing water-insoluble residues while maintaining sufficient rheological performance remains a key challenge for guar gum-based fracturing fluid thickeners. Natural guar gum (GG) is widely used in fracturing fluids, but its relatively high content of water-insoluble residues can impair permeability and reduce fracture conductivity. In this study, GG was modified by low-substitution etherification using a glycerol ether-based modifier (GMH-1) under mild alkaline reaction conditions to develop a reduced-residue thickener for fracturing fluid applications. The modification conditions were optimized through an L9 orthogonal design combined with single-factor analysis. Under the optimal conditions of 35 \u00b0C, 2.0 h, 2.0 wt % NaOH, and 0.2 wt % GMH-1, the modified product (GMGG) exhibited an apparent viscosity of 125.3 mPa\u00b7s and a water-insoluble residue content of 5.1% in a 0.6 wt % aqueous solution; in comparison, GG showed a viscosity of 89.3 mPa\u00b7s and a residue content of 12.4%. FTIR, UV-Vis spectroscopy, and elemental analysis provided indirect but consistent evidence for low-substitution chemical modification and the introduction of oxygen-containing hydrophilic groups while largely preserving the polysaccharide backbone. GMGG also showed improved rheological and thermal response behavior, suggesting that low-substitution glycerol etherification may provide a feasible route to balance residue reduction and viscosity enhancement. These results indicate the potential of this strategy for designing reduced-residue guar-based thickeners for fracturing fluids, while further molecular-level characterization is still required to determine the exact substitution pattern and mechanism.<\/jats:p>","DOI":"10.3390\/gels12070619","type":"journal-article","created":{"date-parts":[[2026,7,9]],"date-time":"2026-07-09T11:55:32Z","timestamp":1783598132000},"page":"619","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Low-Substitution Glycerol Etherification of Guar Gum for Reduced-Residue Fracturing Fluids"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2195-3575","authenticated-orcid":false,"given":"Yongfei","family":"Li","sequence":"first","affiliation":[{"name":"Engineering Research Center of Oil and Gas Field Chemistry, Universities of Shaanxi Province, Xi\u2019an Shiyou University, Xi\u2019an 710065, China"},{"name":"Shaanxi Province Key Laboratory of Environmental Pollution Control and Reservoir Protection Technology of Oilfields, Xi\u2019an Shiyou University, Xi\u2019an 710065, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Boyang","family":"Shen","sequence":"additional","affiliation":[{"name":"Engineering Research Center of Oil and Gas Field Chemistry, Universities of Shaanxi Province, Xi\u2019an Shiyou University, Xi\u2019an 710065, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rong","family":"Li","sequence":"additional","affiliation":[{"name":"Karamay Sanda High-Tech Co., Ltd., Karamay 834000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Huili","family":"He","sequence":"additional","affiliation":[{"name":"Karamay Sanda High-Tech Co., Ltd., Karamay 834000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shiyu","family":"Wang","sequence":"additional","affiliation":[{"name":"Engineering Research Center of Oil and Gas Field Chemistry, Universities of Shaanxi Province, Xi\u2019an Shiyou University, Xi\u2019an 710065, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-2208-1873","authenticated-orcid":false,"given":"Qian","family":"Wang","sequence":"additional","affiliation":[{"name":"Engineering Research Center of Oil and Gas Field Chemistry, Universities of Shaanxi Province, Xi\u2019an Shiyou University, Xi\u2019an 710065, China"},{"name":"Shaanxi Province Key Laboratory of Environmental Pollution Control and Reservoir Protection Technology of Oilfields, Xi\u2019an Shiyou University, Xi\u2019an 710065, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0375-1438","authenticated-orcid":false,"given":"Maogang","family":"Li","sequence":"additional","affiliation":[{"name":"Engineering Research Center of Oil and Gas Field Chemistry, Universities of Shaanxi Province, Xi\u2019an Shiyou University, Xi\u2019an 710065, China"},{"name":"Shaanxi Province Key Laboratory of Environmental Pollution Control and Reservoir Protection Technology of Oilfields, Xi\u2019an Shiyou University, Xi\u2019an 710065, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3711-4250","authenticated-orcid":false,"given":"Gang","family":"Chen","sequence":"additional","affiliation":[{"name":"Engineering Research Center of Oil and Gas Field Chemistry, Universities of Shaanxi Province, Xi\u2019an Shiyou University, Xi\u2019an 710065, China"},{"name":"Shaanxi Province Key Laboratory of Environmental Pollution Control and Reservoir Protection Technology of Oilfields, Xi\u2019an Shiyou University, Xi\u2019an 710065, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"361","DOI":"10.1016\/j.ijbiomac.2016.04.001","article-title":"Guar gum as a promising starting material for diverse applications: A review","volume":"88","author":"Thombare","year":"2016","journal-title":"Int. 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