Evaluating the impact of extensional rheology on agricultural spray retention
department or school: Applied Science, Faculty of
department or school: Chemical and Biological Engineering, Department of
data provider: DSpace
degree campus: UBCV
creator: Moussavi, Yeganehsadat
issued: 2025-11-26T21:06:04Z
issued: 2025
related degree: Master of Applied Science - MASc
degree grantor: University of British Columbia
description: Agrochemicals play a vital role in enhancing crop productivity, yet poor retention and unintended spreading during spraying pose environmental and economic risks. This research addresses these challenges by investigating strategies to improve the effectiveness and stability of agricultural spray formulations through a comprehensive assessment of spray application parameters, polymer solution extensional rheology, the influence of surfactant addition, and the effects of stabilizing agents on storage duration. The findings reveal that nozzle pressure and translation speed jointly influence droplet deposition and retention behavior, with deviations observed at higher nozzle speeds. Beyond application mechanics, molecular characterization highlights the critical role of extensional relaxation time (Î»â), the time required for a polymer solution to recover its original structure after stretching, as a key determinant of spray deposition. This parameter serves as a practical and rapid predictor for assessing formulation performance through extensional rheology tests. The study further demonstrates that ionic surfactants alter the rheological response of polymer solutions, whereas nonionic surfactants primarily act as interfacial agents without significantly affecting relaxation dynamics. Polymer-based solutions exhibit superior leaf retention compared with surfactant-only systems, primarily due to their inherent viscoelastic properties. To improve storage stability, isopropyl alcohol (IPA) and α-tocopherol were identified as effective stabilizers, particularly under refrigerated conditions. Overall, this work establishes a mechanistic link between spray operational factors, extensional rheology, and deposition outcomes. It provides a standardized framework for evaluating spray retention and introduces stabilizing strategies that extend formulation shelf life, contributing to the development of more efficient and sustainable agricultural spray technologies.
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/93033
note: Evaluating the Impact of Extensional Rheology onAgricultural Spray RetentionbyYeganehsadat MoussaviB.Sc., Amirkabir University of Technology, 2021A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THEREQUIREMENTS FOR THE DEGREE OFMASTER OF APPLIED SCIENCEinTHE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES(Chemical and Biological Engineering)THE UNIVERSITY OF BRITISH COLUMBIA(Vancouver)November 2025© Yeganehsadat Moussavi, 2025The following individuals certify that they have read, and recommend to the Facultyof Graduate and Postdoctoral Studies for acceptance, the thesis entitled:Evaluating the impact of Extensional Rheology on Agricultural Spray Retentionsubmitted by Yeganehsadat Moussavi in partial fulfilment of the requirements for thedegree of Master of Applied Science in Chemical and Biological Engineering.John M. Frostad, Associate Professor, Chemical and Biological Engineering, UBCSupervisorDr. Mark Martinez, Professor, Chemical and Biological Engineering, UBCSupervisory Committee MemberDr. Sean Smukler, Associate Professor, Land and Food Systems, UBCSupervisory Committee MemberiiAbstractAgrochemicals play a vital role in enhancing crop productivity, yet poor retentionand unintended spreading during spraying pose environmental and economic risks.This research addresses these challenges by investigating strategies to improve theeffectiveness and stability of agricultural spray formulations through a comprehensiveassessment of spray application parameters, polymer solution extensional rheology,the influence of surfactant addition, and the effects of stabilizing agents on storageduration. The findings reveal that nozzle pressure and translation speed jointlyinfluence droplet deposition and retention behavior, with deviations observed athigher nozzle speeds.Beyond application mechanics, molecular characterization highlights the critical roleof extensional relaxation time (λE), the time required for a polymer solution torecover its original structure after stretching, a…
has type: Thesis/Dissertation
date issued: 2026-05
is shown at: 10.14288/1.0450867
language: eng
degree discipline: Chemical and Biological Engineering
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Frostad, John M.
type: Text
identifier URI: http://hdl.handle.net/2429/93033